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Liu D, Zhu D, Qin Q. Direct angiographic comparison of different velocity-selective saturation, inversion, and DANTE labeling modules on cerebral arteries. Magn Reson Med 2024; 92:761-771. [PMID: 38523590 PMCID: PMC11142876 DOI: 10.1002/mrm.30085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/07/2024] [Accepted: 02/28/2024] [Indexed: 03/26/2024]
Abstract
PURPOSE This study evaluated the velocity-selective (VS) MRA with different VS labeling modules, including double refocused hyperbolic tangent, eight-segment B1-insensitive rotation, delay alternating with nutation for tailored excitation, Fourier transform-based VS saturation, and Fourier transform-based inversion. METHODS These five VS labeling modules were evaluated first through Bloch simulations, and then using VSMRA directly on various cerebral arteries of healthy subjects. The relative signal ratios from arterial ROIs and surrounding tissues as well as relative arteria-tissue contrast ratios of different methods were compared. RESULTS Double refocused hyperbolic tangent and eight-segment B1-insensitive rotation showed very similar labeling effects. Delay alternating with nutation for tailored excitation yielded high arterial signal but with residual tissue signal due to the spatial banding effect. Fourier transform-based VS saturation with half the time of other techniques serves as an efficient nonsubtractive VSMRA method, but the remaining tissue signal still obscured some small distal arteries that were delineated by other subtraction-based VSMRA, allowing more complete cancelation of static tissue. Fourier transform-based inversion produced the highest arterial signal in VSMRA with minimal tissue background. CONCLUSION This is the first study that angiographically compared five different VS labeling modules. Their labeling characteristics on arteries and tissue and implications for VSMRA and VS arterial spin labeling are discussed.
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Affiliation(s)
- Dapeng Liu
- Department of Radiology and Radiological Science; Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Dan Zhu
- Department of Radiology and Radiological Science; Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Qin Qin
- Department of Radiology and Radiological Science; Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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2
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Xu F, Xu C, Zhu D, Liu D, Lu H, Qin Q. Evaluating cerebrovascular reactivity measured by velocity selective inversion arterial spin labeling with different post-labeling delays: The effect of fast flow. Magn Reson Med 2024. [PMID: 38852173 DOI: 10.1002/mrm.30166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 04/24/2024] [Accepted: 05/08/2024] [Indexed: 06/11/2024]
Abstract
PURPOSE Velocity selective arterial spin labeling (VSASL) quantification assumes that the labeled bolus continuously moves into the imaging voxel during the post-labeling delay (PLD). Faster blood flow could lead to a bolus duration shorter than the applied PLD of VSASL and cause underestimation of cerebral blood flow (CBF). This study aims to evaluate the performance of velocity-selective inversion (VSI) prepared arterial spin labeling (ASL) with different PLDs and pseudo-continuous ASL (PCASL) for quantification of hypercapnia-induced cerebrovascular reactivity (CVR), using phase-contrast (PC) MRI as a global reference. METHODS We compared CVR obtained by VSI-ASL with PLD of 1520 ms (VSASL-1520), 1000 ms (VSASL-1000), and 500 ms (VSASL-500), PCASL with PLD of 1800 ms (PCASL-1800), and PC MRI on eight healthy volunteers at two sessions. RESULTS Compared with PC MRI, VSASL-1520 produced significantly lower global CVR values, while PCASL-1800, VSASL-1000, and VSASL-500 yielded more consistent results. The reduced CVR in VSASL-1520 was more pronounced in carotid territories including frontal and temporal lobes than in vertebral territories such as the occipital lobe. This is largely caused by the underestimated perfusion during hypercapnia due to the reduced bolus duration being less than the PLD. CONCLUSION Although VSASL offers certain advantages over spatially selective ASL due to its reduced susceptibility to delayed ATT, this technique is prone to biases when the ATT is excessively short. Therefore, a short PLD should be employed for reliable perfusion and CVR quantification in populations or conditions with fast flow.
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Affiliation(s)
- Feng Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Cuimei Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
| | - Dan Zhu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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3
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Guo J. Optimizing background suppression for dual-module velocity-selective arterial spin labeling: Without using additional background-suppression pulses. Magn Reson Med 2024; 91:2320-2331. [PMID: 38173296 PMCID: PMC10997483 DOI: 10.1002/mrm.29995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/12/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024]
Abstract
PURPOSE Background suppression (BS) is recommended in arterial spin labeling (ASL) for improved SNR but is difficult to optimize in existing velocity-selective ASL (VSASL) methods. Dual-module VSASL (dm-VSASL) enables delay-insensitive, robust, and SNR-efficient perfusion imaging, while allowing efficient BS, but its optimization has yet to be thoroughly investigated. METHODS The inversion effects of the velocity-selective labeling pulses, such as velocity-selective inversion (VSI), can be used for BS, and were modeled for optimizing BS in dm-VSASL. In vivo experiments using dual-module VSI (dm-VSI) were performed to compare two BS strategies: a conventional one with additional BS pulses and a new one without any BS pulse. Their BS performance, temporal noise, and temporal SNR were examined and compared, with pulsed and pseudo-continuous ASL (PASL and PCASL) as the reference. RESULTS The in vivo experiments validated the BS modeling. Strong positive linear correlations (r > 0.82, p < 0.0001) between the temporal noise and the tissue signal were found in PASL/PCASL and dm-VSI. Optimal BS can be achieved with and without additional BS pulses in dm-VSI; the latter improved the ASL signals by 8.5% in gray matter (p = 0.006) and 12.2% in white matter (p = 0.014) and tended to provide better temporal SNR. The dm-VSI measured significantly higher ASL signal (p < 0.016) and temporal SNR (p < 0.018) than PASL and PCASL. Complex reconstruction was found necessary with aggressive BS. CONCLUSION Guided by modeling, optimal BS can be achieved without any BS pulse in dm-VSASL, further improving the ASL signal and the SNR performance.
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Affiliation(s)
- Jia Guo
- Department of Bioengineering, University of California Riverside, Riverside, CA, USA
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4
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Suzuki Y, Clement P, Dai W, Dolui S, Fernández-Seara M, Lindner T, Mutsaerts HJMM, Petr J, Shao X, Taso M, Thomas DL. ASL lexicon and reporting recommendations: A consensus report from the ISMRM Open Science Initiative for Perfusion Imaging (OSIPI). Magn Reson Med 2024; 91:1743-1760. [PMID: 37876299 PMCID: PMC10950547 DOI: 10.1002/mrm.29815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/22/2023] [Accepted: 07/13/2023] [Indexed: 10/26/2023]
Abstract
The 2015 consensus statement published by the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group and the European Cooperation in Science and Technology ( COST) Action ASL in Dementia aimed to encourage the implementation of robust arterial spin labeling (ASL) perfusion MRI for clinical applications and promote consistency across scanner types, sites, and studies. Subsequently, the recommended 3D pseudo-continuous ASL sequence has been implemented by most major MRI manufacturers. However, ASL remains a rapidly and widely developing field, leading inevitably to further divergence of the technique and its associated terminology, which could cause confusion and hamper research reproducibility. On behalf of the ISMRM Perfusion Study Group, and as part of the ISMRM Open Science Initiative for Perfusion Imaging (OSIPI), the ASL Lexicon Task Force has been working on the development of an ASL Lexicon and Reporting Recommendations for perfusion imaging and analysis, aiming to (1) develop standardized, consensus nomenclature and terminology for the broad range of ASL imaging techniques and parameters, as well as for the physiological constants required for quantitative analysis; and (2) provide a community-endorsed recommendation of the imaging parameters that we encourage authors to include when describing ASL methods in scientific reports/papers. In this paper, the sequences and parameters in (pseudo-)continuous ASL, pulsed ASL, velocity-selective ASL, and multi-timepoint ASL for brain perfusion imaging are included. However, the content of the lexicon is not intended to be limited to these techniques, and this paper provides the foundation for a growing online inventory that will be extended by the community as further methods and improvements are developed and established.
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Affiliation(s)
- Yuriko Suzuki
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Patricia Clement
- Department of Medical Imaging, Ghent University Hospital, Ghent, Belgium
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
| | - Weiying Dai
- State University of New York at Binghamton, Binghamton, NY, USA
| | - Sudipto Dolui
- Department of Radiology, University of Pennsylvania, Philadelphia, USA
| | - Maria Fernández-Seara
- Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain
- IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain
| | | | - Henk JMM Mutsaerts
- Department of Radiology and Nuclear medicine, Amsterdam Neuroscience, Amsterdam University Medical Center, the Netherlands, Amsterdam
| | - Jan Petr
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden, Germany
| | - Xingfeng Shao
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Manuel Taso
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - David L Thomas
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, UK
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Liu TT, Wong EC, Bolar DS, Chen C, Barnes RS. A mathematical model for velocity-selective arterial spin labeling. Magn Reson Med 2024; 91:1384-1403. [PMID: 38181170 DOI: 10.1002/mrm.29935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/04/2023] [Accepted: 11/03/2023] [Indexed: 01/07/2024]
Abstract
PURPOSE To present a theoretical framework that rigorously defines and analyzes key concepts and quantities for velocity selective arterial spin labeling (VSASL). THEORY AND METHODS An expression for the VSASL arterial delivery function is derived based on (1) labeling and saturation profiles as a function of velocity and (2) physiologically plausible approximations of changes in acceleration and velocity across the vascular system. The dependence of labeling efficiency on the amplitude and effective bolus width of the arterial delivery function is defined. Factors that affect the effective bolus width are examined, and timing requirements to minimize quantitation errors are derived. RESULTS The model predicts that a flow-dependent negative bias in the effective bolus width can occur when velocity selective inversion (VSI) is used for the labeling module and velocity selective saturation (VSS) is used for the vascular crushing module. The bias can be minimized by choosing a nominal labeling cutoff velocity that is lower than the nominal cutoff velocity of the vascular crushing module. CONCLUSION The elements of the model are specified in a general fashion such that future advances can be readily integrated. The model can facilitate further efforts to understand and characterize the performance of VSASL and provide critical theoretical insights that can be used to design future experiments and develop novel VSASL approaches.
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Affiliation(s)
- Thomas T Liu
- Center for Functional MRI, University of California San Diego, La Jolla, California, USA
- Department of Radiology, University of California San Diego, La Jolla, California, USA
- Department of Psychiatry, University of California San Diego, La Jolla, California, USA
| | - Eric C Wong
- Center for Functional MRI, University of California San Diego, La Jolla, California, USA
- Department of Radiology, University of California San Diego, La Jolla, California, USA
- Department of Psychiatry, University of California San Diego, La Jolla, California, USA
| | - Divya S Bolar
- Center for Functional MRI, University of California San Diego, La Jolla, California, USA
- Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Conan Chen
- Center for Functional MRI, University of California San Diego, La Jolla, California, USA
- Department of Radiology, University of California San Diego, La Jolla, California, USA
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, California, USA
| | - Ryan S Barnes
- Center for Functional MRI, University of California San Diego, La Jolla, California, USA
- Department of Radiology, University of California San Diego, La Jolla, California, USA
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, California, USA
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Taso M, Alsop DC. Arterial Spin Labeling Perfusion Imaging. Magn Reson Imaging Clin N Am 2024; 32:63-72. [PMID: 38007283 DOI: 10.1016/j.mric.2023.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2023]
Abstract
Noninvasive imaging of tissue perfusion is a valuable tool for both research and clinical applications. Arterial spin labeling (ASL) is a contrast-free perfusion imaging method that enables measuring and quantifying tissue blood flow using MR imaging. ASL uses radiofrequency and magnetic field gradient pulses to label arterial blood water, which then serves as an endogenous tracer. This review highlights the basic mechanism of ASL perfusion imaging, labeling strategies, and quantification. ASL has been widely used during the past 30 years for the study of normal brain function as well as in multiple neurovascular, neuro-oncological and degenerative pathologic conditions.
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Affiliation(s)
- Manuel Taso
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - David C Alsop
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
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Lambrecht S, Liu D, Dzaye O, Kamson DO, Reis J, Liebig T, Holdhoff M, Van Zijl P, Qin Q, Lin DDM. Velocity-Selective Arterial Spin Labeling Perfusion in Monitoring High Grade Gliomas Following Therapy: Clinical Feasibility at 1.5T and Comparison with Dynamic Susceptibility Contrast Perfusion. Brain Sci 2024; 14:126. [PMID: 38391701 PMCID: PMC10886779 DOI: 10.3390/brainsci14020126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 01/19/2024] [Accepted: 01/20/2024] [Indexed: 02/24/2024] Open
Abstract
MR perfusion imaging is important in the clinical evaluation of primary brain tumors, particularly in differentiating between true progression and treatment-induced change. The utility of velocity-selective ASL (VSASL) compared to the more commonly utilized DSC perfusion technique was assessed in routine clinical surveillance MR exams of 28 patients with high-grade gliomas at 1.5T. Using RANO criteria, patients were assigned to two groups, one with detectable residual/recurrent tumor ("RT", n = 9), and the other with no detectable residual/recurrent tumor ("NRT", n = 19). An ROI was drawn to encompass the largest dimension of the lesion with measures normalized against normal gray matter to yield rCBF and tSNR from VSASL, as well as rCBF and leakage-corrected relative CBV (lc-rCBV) from DSC. VSASL (rCBF and tSNR) and DSC (rCBF and lc-rCBV) metrics were significantly higher in the RT group than the NRT group allowing adequate discrimination (p < 0.05, Mann-Whitney test). Lin's concordance analyses showed moderate to excellent concordance between the two methods, with a stronger, moderate correlation between VSASL rCBF and DSC lc-rCBV (r = 0.57, p = 0.002; Pearson's correlation). These results suggest that VSASL is clinically feasible at 1.5T and has the potential to offer a noninvasive alternative to DSC perfusion in monitoring high-grade gliomas following therapy.
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Affiliation(s)
- Sebastian Lambrecht
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Institute of Neuroradiology, University Hospital LMU Munich, 81377 Munich, Germany
| | - Dapeng Liu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Omar Dzaye
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - David O Kamson
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Jonas Reis
- Institute of Neuroradiology, University Hospital LMU Munich, 81377 Munich, Germany
| | - Thomas Liebig
- Institute of Neuroradiology, University Hospital LMU Munich, 81377 Munich, Germany
| | - Matthias Holdhoff
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Peter Van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Qin Qin
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Doris D M Lin
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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8
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Zhu D, Xu F, Liu D, Hillis AE, Lin D, van Zijl PC, Qin Q. Evaluation of 3D stack-of-spiral turbo FLASH acquisitions for pseudo-continuous and velocity-selective ASL-derived brain perfusion mapping. Magn Reson Med 2023; 90:939-949. [PMID: 37125611 PMCID: PMC11054979 DOI: 10.1002/mrm.29681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 03/28/2023] [Accepted: 04/07/2023] [Indexed: 05/02/2023]
Abstract
PURPOSE The most-used 3D acquisitions for ASL are gradient and spin echo (GRASE)- and stack-of-spiral (SOS)-based fast spin echo, which require multiple shots. Alternatively, turbo FLASH (TFL) allows longer echo trains, and SOS-TFL has the potential to reduce the number of shots to even single-shot, thus improving the temporal resolution. Here we compare the performance of 3D SOS-TFL and 3D GRASE for ASL at 3T. METHODS The 3D SOS-TFL readout was optimized with respect to fat suppression and excitation flip angles for pseudo-continuous ASL- and velocity-selective (VS)ASL-derived cerebral blood flow (CBF) mapping as well as for VSASL-derived cerebral blood volume (CBV) mapping. Results were compared with 3D GRASE readout on healthy volunteers in terms of perfusion quantification and temporal SNR (tSNR) efficiency. CBF and CBV mapping derived from 3D SOS-TFL-based ASL was demonstrated on one stroke patient, and the potential for single-shot acquisitions was exemplified. RESULTS SOS-TFL with a 15° flip angle resulted in adequate tSNR efficiency with negligible image blurring. Selective water excitation was necessary to eliminate fat-induced artifacts. For pseudo-continuous ASL- and VSASL-based CBF and CBV mapping, compared to the employed four-shot 3D GRASE with an acceleration factor of 2, the fully sampled 3D SOS-TFL delivered comparable performance (with a similar scan time) using three shots, which could be further undersampled to achieve single-shot acquisition with higher tSNR efficiency. SOS-TFL had reduced CSF contamination for VSASL-CBF. CONCLUSION 3D SOS-TFL acquisition was found to be a viable substitute for 3D GRASE for ASL with sufficient tSNR efficiency, minimal relaxation-induced blurring, reduced CSF contamination, and the potential of single-shot, especially for VSASL.
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Affiliation(s)
- Dan Zhu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Feng Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dapeng Liu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Argye Elizabeth Hillis
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Doris Lin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter C.M. van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Qin Qin
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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9
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Lee S, Meyer BP, Hernandez-Garcia L, Kurpad SN, Schmit BD, Budde MD. Comparison and optimization of pCASL and VSASL for rat thoracolumbar spinal cord MRI at 9.4 T. Magn Reson Med 2023; 89:2305-2317. [PMID: 36744728 PMCID: PMC10050093 DOI: 10.1002/mrm.29603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 01/06/2023] [Accepted: 01/12/2023] [Indexed: 02/07/2023]
Abstract
PURPOSE To evaluate pseudo-continuous arterial spin labeling (pCASL) and velocity-selective arterial spin labeling (VSASL) for quantification of spinal cord blood flow (SCBF) in the rat thoracolumbar spinal cord. METHODS Labeling efficiency (LE) was compared between pCASL and three VSASL variants in simulations and both phantom and in vivo experiments at 9.4 T. For pCASL, the effects of label plane position and shimming were systematically evaluated. For VSASL, the effects of composite pulses and phase cycling were evaluated to reduce artifacts. Additionally, vessel suppression, respiratory, and cardiac gating were evaluated to reduce motion artifacts. pCASL and VSASL maps of spinal cord blood flow were acquired with the optimized protocols. RESULTS LE of the descending aorta was larger in pCASL compared to VSASL variants. In pCASL, LE off-isocenter was improved by local shimming positioned at the label plane and the anatomical level of labeling for the thoracic cord was only viable at the level of the T10 vertebra. Cardiac gating was essential to reduce motion artifacts. Both pCASL and VSASL successfully demonstrated comparable SCBF values in the thoracolumbar cord. CONCLUSION pCASL demonstrated high and consistent LE in the thoracic aorta, and VSASL was also feasible, but with reduced efficiency. A combination of cardiac gating and recording of actual post-label delays was important for accurate SCBF quantification. These results highlight the challenges and solutions to achieve sufficient ASL labeling and contrast at high field in organs prone to motion.
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Affiliation(s)
- Seongtaek Lee
- Joint Department of Biomedical Engineering, Marquette University & Medical College of Wisconsin, Milwaukee, WI
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI
| | - Briana P Meyer
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI
| | - Luis Hernandez-Garcia
- FMRI Laboratory, Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI
| | - Shekar N Kurpad
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI
- Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI
| | - Brian D Schmit
- Joint Department of Biomedical Engineering, Marquette University & Medical College of Wisconsin, Milwaukee, WI
| | - Matthew D Budde
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI
- Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, WI
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10
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Taso M, Aramendía-Vidaurreta V, Englund EK, Francis S, Franklin S, Madhuranthakam AJ, Martirosian P, Nayak KS, Qin Q, Shao X, Thomas DL, Zun Z, Fernández-Seara MA. Update on state-of-the-art for arterial spin labeling (ASL) human perfusion imaging outside of the brain. Magn Reson Med 2023; 89:1754-1776. [PMID: 36747380 DOI: 10.1002/mrm.29609] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/09/2023] [Accepted: 01/16/2023] [Indexed: 02/08/2023]
Abstract
This review article provides an overview of developments for arterial spin labeling (ASL) perfusion imaging in the body (i.e., outside of the brain). It is part of a series of review/recommendation papers from the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group. In this review, we focus on specific challenges and developments tailored for ASL in a variety of body locations. After presenting common challenges, organ-specific reviews of challenges and developments are presented, including kidneys, lungs, heart (myocardium), placenta, eye (retina), liver, pancreas, and muscle, which are regions that have seen the most developments outside of the brain. Summaries and recommendations of acquisition parameters (when appropriate) are provided for each organ. We then explore the possibilities for wider adoption of body ASL based on large standardization efforts, as well as the potential opportunities based on recent advances in high/low-field systems and machine-learning. This review seeks to provide an overview of the current state-of-the-art of ASL for applications in the body, highlighting ongoing challenges and solutions that aim to enable more widespread use of the technique in clinical practice.
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Affiliation(s)
- Manuel Taso
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | | | - Erin K Englund
- Department of Radiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Susan Francis
- Sir Peter Mansfield Imaging Center, University of Nottingham, Nottingham, UK
| | - Suzanne Franklin
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
- Center for Image Sciences, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Ananth J Madhuranthakam
- Department of Radiology, Advanced Imaging Research Center, and Biomedical Engineering, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Petros Martirosian
- Section on Experimental Radiology, Department of Radiology, University Hospital of Tuebingen, Tuebingen, Germany
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
| | - Xingfeng Shao
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - David L Thomas
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Zungho Zun
- Department of Radiology, Weill Cornell Medicine, New York, New York, USA
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11
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Xu F, Liu D, Zhu D, Hillis AE, Bakker A, Soldan A, Albert MS, Lin DDM, Qin Q. Test-retest reliability of 3D velocity-selective arterial spin labeling for detecting normal variations of cerebral blood flow. Neuroimage 2023; 271:120039. [PMID: 36931331 PMCID: PMC10150252 DOI: 10.1016/j.neuroimage.2023.120039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/23/2023] [Accepted: 03/14/2023] [Indexed: 03/18/2023] Open
Abstract
Velocity-selective inversion (VSI) based velocity-selective arterial spin labeling (VSASL) has been developed to measure cerebral blood flow (CBF) with low susceptibility to the prolonged arterial transit time and high sensitivity to brain perfusion signal. The purpose of this magnetic resonance imaging study is to evaluate the test-retest reliability of a VSI-prepared 3D VSASL protocol with whole-brain coverage to detect baseline CBF variations among cognitively normal participants in different brain regions. Coefficients of variation (CoV) of both absolute and relative CBF across scans or sessions, subjects, and gray matter regions were calculated, and corresponding intraclass correlation coefficients (ICC) were computed. The higher between-subject CoV of absolute CBF (13.4 ± 2.0%) over within-subject CoV (within-session: 3.8 ± 1.1%; between-session: 4.9 ± 0.9%) yielded moderate to excellent ICC (within-session: 0.88±0.08; between-session: 0.77±0.14) to detect normal variations of individual CBF. The higher between-region CoV of relative CBF (11.4 ± 3.0%) over within-region CoV (within-session: 2.3 ± 0.9%; between-session: 3.3 ± 1.0%) yielded excellent ICC (within-session: 0.92±0.06; between-session: 0.85±0.12) to detect normal variations of regional CBF. Age, blood pressure, end-tidal CO2, and hematocrit partially explained the variability of CBF across subjects. Together these results show excellent test-retest reliability of VSASL to detect both between-subject and between-region variations supporting its clinical utility.
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Affiliation(s)
- Feng Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University, Baltimore, MD 21205, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA.
| | - Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University, Baltimore, MD 21205, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Dan Zhu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University, Baltimore, MD 21205, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Argye E Hillis
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Arnold Bakker
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Anja Soldan
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Marilyn S Albert
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Doris D M Lin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University, Baltimore, MD 21205, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
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12
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Guo J. Robust dual-module velocity-selective arterial spin labeling (dm-VSASL) with velocity-selective saturation and inversion. Magn Reson Med 2023; 89:1026-1040. [PMID: 36336852 PMCID: PMC9792445 DOI: 10.1002/mrm.29513] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 10/02/2022] [Accepted: 10/13/2022] [Indexed: 11/09/2022]
Abstract
PURPOSE Compared to conventional arterial spin labeling (ASL) methods, velocity-selective ASL (VSASL) is more sensitive to artifacts from eddy currents, diffusion attenuation, and motion. Background suppression is typically suboptimal in VSASL, especially of CSF. As a result, the temporal SNR and quantification accuracy of VSASL are compromised, hindering its application despite its advantage of being delay-insensitive. METHODS A novel dual-module VSASL (dm-VSASL) strategy is developed to improve the SNR efficiency and the temporal SNR with a more balanced gradient configuration in the label/control image acquisition. This strategy applies for both VS saturation (VSS) and VS inversion (VSI) labeling. The dm-VSASL schemes were compared with single-module labeling and a previously developed multi-module schemes for the SNR performance, background suppression efficacy, and sensitivity to artifacts in simulation and in vivo experiments, using pulsed ASL as the reference. RESULTS Dm-VSASL enabled more robust labeling and efficient backgroud suppre across brain tissues, especially of CSF, resulting in significantly reduced artifacts and improved temporal SNR. Compared to single-module labeling, dm-VSASL significantly improved the temporal SNR in gray (by 90.8% and 94.9% for dm-VSS and dm-VSI, respectively; P < 0.001) and white (by 41.5% and 55.1% for dm-VSS and dm-VSI, respectively; P < 0.002) matter. Dm-VSI also improved the SNR of VSI by 5.4% (P = 0.018). CONCLUSION Dm-VSASL can significantly improve the robustness of VS labeling, reduce artifacts, and allow efficient background suppression. When implemented with VSI, it provides the highest SNR efficiency among VSASL methods. Dm-VSASL is a powerful ASL method for robust, accurate, and delay-insensitive perfusion mapping.
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Affiliation(s)
- Jia Guo
- Correspondence Jia Guo, PhD, Department of Bioengineering, 900 University Ave, University of California Riverside, Riverside, CA 92521, USA,
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13
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Zun Z, Shin T. Velocity-selective excitation: Principles and applications. NMR IN BIOMEDICINE 2023; 36:e4820. [PMID: 35994473 PMCID: PMC9845137 DOI: 10.1002/nbm.4820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 07/12/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Velocity-selective (VS) excitation is a relatively new type of excitation that can be useful for generating image contrast based on spin's motion. This review aims to explain the principles of VS excitation and their utilization for clinical applications. We first review the generalized excitation k-space formalism, which reveals a Fourier relationship between sequence parameters and excitation profiles for spins with arbitrary spatial location, off-resonance, and velocity. Based on the k-space framework, we analyze practical VS excitation pulse sequences that yield sinusoidal or sinc-shaped velocity profiles. Then we demonstrate how these two types of VS excitation can be used as magnetization preparation for clinical applications, including saturation- or inversion-based arterial spin labeling and black- or bright-blood angiography. We also discuss practical considerations and issues for each application, including the determination of design parameters and the effects of MR system errors, such as magnetic field offsets and eddy currents.
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Affiliation(s)
- Zungho Zun
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Taehoon Shin
- Division of Mechanical and Biomedical Engineering, Ewha Womans University, Seoul, South Korea
- Graduate Program in Smart Factory, Ewha Womans University, Seoul, South Korea
- Department of Medicine, Case Western Reserve University, Cleveland, OH, United States
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14
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Qin Q, Alsop DC, Bolar DS, Hernandez‐Garcia L, Meakin J, Liu D, Nayak KS, Schmid S, van Osch MJP, Wong EC, Woods JG, Zaharchuk G, Zhao MY, Zun Z, Guo J. Velocity-selective arterial spin labeling perfusion MRI: A review of the state of the art and recommendations for clinical implementation. Magn Reson Med 2022; 88:1528-1547. [PMID: 35819184 PMCID: PMC9543181 DOI: 10.1002/mrm.29371] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/16/2022] [Accepted: 06/08/2022] [Indexed: 12/11/2022]
Abstract
This review article provides an overview of the current status of velocity-selective arterial spin labeling (VSASL) perfusion MRI and is part of a wider effort arising from the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group. Since publication of the 2015 consensus paper on arterial spin labeling (ASL) for cerebral perfusion imaging, important advancements have been made in the field. The ASL community has, therefore, decided to provide an extended perspective on various aspects of technical development and application. Because VSASL has the potential to become a principal ASL method because of its unique advantages over traditional approaches, an in-depth discussion was warranted. VSASL labels blood based on its velocity and creates a magnetic bolus immediately proximal to the microvasculature within the imaging volume. VSASL is, therefore, insensitive to transit delay effects, in contrast to spatially selective pulsed and (pseudo-) continuous ASL approaches. Recent technical developments have improved the robustness and the labeling efficiency of VSASL, making it a potentially more favorable ASL approach in a wide range of applications where transit delay effects are of concern. In this review article, we (1) describe the concepts and theoretical basis of VSASL; (2) describe different variants of VSASL and their implementation; (3) provide recommended parameters and practices for clinical adoption; (4) describe challenges in developing and implementing VSASL; and (5) describe its current applications. As VSASL continues to undergo rapid development, the focus of this review is to summarize the fundamental concepts of VSASL, describe existing VSASL techniques and applications, and provide recommendations to help the clinical community adopt VSASL.
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Affiliation(s)
- Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - David C. Alsop
- Department of RadiologyBeth Israel Deaconess Medical Center and Harvard Medical SchoolBostonMassachusettsUSA
| | - Divya S. Bolar
- Center for Functional Magnetic Resonance Imaging, Department of RadiologyUniversity of CaliforniaSan Diego La JollaCaliforniaUSA
| | | | - James Meakin
- Department of Radiology, Nuclear Medicine and AnatomyRadboud University Medical CenterNijmegenThe Netherlands
| | - Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological ScienceJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Krishna S. Nayak
- Magnetic Resonance Engineering Laboratory, Ming Hsieh Department of Electrical EngineeringUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Sophie Schmid
- C.J. Gorter Center for high field MRI, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Matthias J. P. van Osch
- C.J. Gorter Center for high field MRI, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Eric C. Wong
- Center for Functional Magnetic Resonance Imaging, Department of RadiologyUniversity of CaliforniaSan Diego La JollaCaliforniaUSA
| | - Joseph G. Woods
- Center for Functional Magnetic Resonance Imaging, Department of RadiologyUniversity of CaliforniaSan Diego La JollaCaliforniaUSA
| | - Greg Zaharchuk
- Department of RadiologyStanford UniversityStanfordCaliforniaUSA
| | - Moss Y. Zhao
- Department of RadiologyStanford UniversityStanfordCaliforniaUSA
| | - Zungho Zun
- Department of RadiologyWeill Cornell MedicineNew YorkNew YorkUSA
| | - Jia Guo
- Department of BioengineeringUniversity of California RiversideRiversideCaliforniaUSA
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15
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Li W, Xu F, Zhu D, van Zijl PCM, Qin Q. T 2 -oximetry-based cerebral venous oxygenation mapping using Fourier-transform-based velocity-selective pulse trains. Magn Reson Med 2022; 88:1292-1302. [PMID: 35608208 PMCID: PMC9247032 DOI: 10.1002/mrm.29300] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/14/2022]
Abstract
Purpose To develop a T2‐oximetry method for quantitative mapping of cerebral venous oxygenation fraction (Yv) using Fourier‐transform–based velocity‐selective (FT‐VS) pulse trains. Methods The venous isolation preparation was achieved by using an FT‐VS inversion plus a nonselective inversion (NSI) pulse to null the arterial blood signal while minimally affected capillary blood flows out into the venular vasculature during the outflow time (TO), and then applying an Fourier transform based velocity selective saturation (FT‐VSS) pulse to suppress the tissue signal. A multi‐echo readout was employed to obtain venous T2 (T2,v) efficiently with the last echo used to detect the residual CSF signal and correct its contamination in the fitting. Here we compared the performance of this FT‐VS–based venous isolation preparations with a traditional velocity‐selective saturation (VSS)–based approach (quantitative imaging of extraction of oxygen and tissue consumption [QUIXOTIC]) with different cutoff velocities for Yv mapping on 6 healthy volunteers at 3 Tesla. Results The FT‐VS–based methods yielded higher venous blood signal and temporal SNR with less CSF contamination than the velocity‐selective saturation–based results. The averaged Yv values across the whole slice measured in different experiments were close to the global Yv measured from the individual internal jugular vein. Conclusion The feasibility of the FT‐VS–based Yv estimation was demonstrated on healthy volunteers. The obtained high venous signal as well as the mitigation of CSF contamination led to a good agreement between the T2,v and Yv measured in the proposed method with the values in the literature. Click here for author‐reader discussions
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Affiliation(s)
- Wenbo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Feng Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Dan Zhu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Peter C M van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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16
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Zhu D, Schär M, Qin Q. Ultrafast B1 mapping with RF-prepared 3D FLASH acquisition: Correcting the bias due to T 1 -induced k-space filtering effect. Magn Reson Med 2022; 88:757-769. [PMID: 35381114 PMCID: PMC9232926 DOI: 10.1002/mrm.29247] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 03/06/2022] [Accepted: 03/07/2022] [Indexed: 01/25/2023]
Abstract
Purpose The traditional radiofrequency (RF)‐prepared B1 mapping technique consists of one scan with an RF preparation module for flip angle‐encoding and a second scan without this module for normalizing. To reduce the T1‐induced k‐space filtering effect, this method is limited to 2D FLASH acquisition with a two‐parameter method. A novel 3D RF‐prepared three‐parameter method for ultrafast B1‐mapping is proposed to correct the T1‐induced quantification bias. Theory The point spread function analysis of FLASH shows that the prepared longitudinal magnetization before the FLASH acquisition and the image signal obeys a linear (not proportional) relationship. The intercept of the linear function causes the quantification bias and can be captured by a third saturated scan. Methods Using the 2D double‐angle method (DAM) as the reference, a 3D RF‐prepared three‐parameter protocol with 9 s duration was compared with the two‐parameter method, as well as the saturated DAM (SDAM) method, the dual refocusing echo acquisition mode (DREAM) method, and the actual flip‐angle imaging (AFI) method, for B1 mapping of brain, breast, and abdomen with different orientations and shim settings at 3T. Results The 3D RF‐prepared three‐parameter method with complex‐subtraction delivered consistently lower RMS error, error mean, error standard deviation, and higher concordance correlation coefficients values than the two‐parameter method, the three‐parameter method with magnitude‐subtraction, the multi‐slice DREAM and the 3D AFI, and were close to the results of 2D or multi‐slice SDAM. Conclusion The proposed ultrafast 3D RF‐prepared three‐parameter method with complex‐subtraction was demonstrated with high accuracy for B1 mapping of brain, breast, and abdomen.
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Affiliation(s)
- Dan Zhu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.,The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael Schär
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Qin Qin
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.,The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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17
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Khalaf A, Nadel H, Dahmoush H. Simultaneously Acquired MRI Arterial Spin-Labeling and Interictal FDG-PET Improves Diagnosis of Pediatric Temporal Lobe Epilepsy. AJNR Am J Neuroradiol 2022; 43:468-473. [PMID: 35210273 PMCID: PMC8910808 DOI: 10.3174/ajnr.a7421] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 12/06/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Interictal FDG-PET scans are a routine diagnostic technique for the identification of epileptogenic foci in the presurgical work-up of medically refractory pediatric epilepsy. With the advent of PET/MR imaging, it has become possible to simultaneously acquire FDG-PET and arterial spin-labeling perfusion data. The objective of this study was to evaluate whether the incorporation of arterial spin-labeling data with interictal FDG-PET could improve the diagnostic performance metrics of FDG-PET for identification of epileptogenic foci. MATERIALS AND METHODS Forty-five pediatric patients with a mean age of 10.8 years were retrospectively included in this study. These patients all underwent PET/MR imaging to diagnose suspected focal epilepsy. RESULTS When compared to interpretations of interictal FDG findings alone, FDG combined with arterial spin-labeling findings resulted in significantly decreased sensitivity (0.64 versus 0.52, P = .02), significantly increased specificity (0.50 versus 0.75, P = .04), and an increased positive predictive value (0.59 versus 0.75). The decreased sensitivity was found to be primarily driven by patients with extratemporal lobe epilepsy, as a subgroup analysis showed decreased sensitivity for patients with extratemporal epilepsy (0.52 versus 0.38, P = .04), but not for temporal epilepsy (0.83 versus 0.75, P = .16). Additionally, substantial agreement between focal FDG hypometabolism and arterial spin-labeling hypoperfusion was demonstrated with the Cohen κ (0.70, P < .01). CONCLUSIONS These findings suggest that simultaneously acquired interictal FDG-PET and arterial spin-labeling data can improve the diagnosis of epileptogenic foci, especially in the setting of temporal lobe epilepsy where they improve specificity and positive predictive value, with preservation of sensitivity.
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Affiliation(s)
- A.M. Khalaf
- From the Stanford University School of Medicine, Department of Radiology, Division of Nuclear Medicine & Molecular Imaging, Division of Pediatric Radiology, Division of Neuroimaging & Neurointervention, Stanford University, Stanford, California
| | - H.R. Nadel
- From the Stanford University School of Medicine, Department of Radiology, Division of Nuclear Medicine & Molecular Imaging, Division of Pediatric Radiology, Division of Neuroimaging & Neurointervention, Stanford University, Stanford, California
| | - H.M. Dahmoush
- From the Stanford University School of Medicine, Department of Radiology, Division of Nuclear Medicine & Molecular Imaging, Division of Pediatric Radiology, Division of Neuroimaging & Neurointervention, Stanford University, Stanford, California
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18
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Perfusion measurement in brain gliomas using velocity-selective arterial spin labeling: comparison with pseudo-continuous arterial spin labeling and dynamic susceptibility contrast MRI. Eur Radiol 2022; 32:2976-2987. [DOI: 10.1007/s00330-021-08406-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/27/2021] [Accepted: 10/12/2021] [Indexed: 12/26/2022]
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19
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Woods JG, Wong EC, Boyd EC, Bolar DS. VESPA ASL: VElocity and SPAtially Selective Arterial Spin Labeling. Magn Reson Med 2022; 87:2667-2684. [PMID: 35061920 DOI: 10.1002/mrm.29159] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/25/2021] [Accepted: 12/22/2021] [Indexed: 01/22/2023]
Abstract
PURPOSE Spatially selective arterial spin labeling (ASL) perfusion MRI is sensitive to arterial transit times (ATT) that can result in inaccurate perfusion quantification when ATTs are long. Velocity-selective ASL is robust to this effect because blood is labeled within the imaging region, allowing immediate label delivery. However, velocity-selective ASL cannot characterize ATTs, which can provide important clinical information. Here, we introduce a novel pulse sequence, called VESPA ASL, that combines velocity-selective and pseudo-continuous ASL to simultaneously label different pools of arterial blood for robust cerebral blood flow (CBF) and ATT measurement. METHODS The VESPA ASL sequence is similar to velocity-selective ASL, but the velocity-selective labeling is made spatially selective, and pseudo-continuous ASL is added to fill the inflow time. The choice of inflow time and other sequence settings were explored. VESPA ASL was compared to multi-delay pseudo-continuous ASL and velocity-selective ASL through simulations and test-retest experiments in healthy volunteers. RESULTS VESPA ASL is shown to accurately measure CBF in the presence of long ATTs, and ATTs < TI can also be measured. Measurements were similar to established ASL techniques when ATT was short. When ATT was long, VESPA ASL measured CBF more accurately than multi-delay pseudo-continuous ASL, which tended to underestimate CBF. CONCLUSION VESPA ASL is a novel and robust approach to simultaneously measure CBF and ATT and offers important advantages over existing methods. It fills an important clinical need for noninvasive perfusion and transit time imaging in vascular diseases with delayed arterial transit.
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Affiliation(s)
- Joseph G Woods
- Center for Functional Magnetic Resonance Imaging, Department of Radiology, University of California San Diego, La Jolla, California, USA
| | - Eric C Wong
- Center for Functional Magnetic Resonance Imaging, Department of Radiology, University of California San Diego, La Jolla, California, USA.,Department of Psychiatry, University of California San Diego, La Jolla, California, USA
| | - Emma C Boyd
- Center for Functional Magnetic Resonance Imaging, Department of Radiology, University of California San Diego, La Jolla, California, USA.,Department of Neurosciences, University of California San Diego, La Jolla, California, USA
| | - Divya S Bolar
- Center for Functional Magnetic Resonance Imaging, Department of Radiology, University of California San Diego, La Jolla, California, USA
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20
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Xu F, Zhu D, Fan H, Lu H, Liu D, Li W, Qin Q. Magnetic resonance angiography and perfusion mapping by arterial spin labeling using Fourier transform-based velocity-selective pulse trains: Examination on a commercial perfusion phantom. Magn Reson Med 2021; 86:1360-1368. [PMID: 33934396 PMCID: PMC8861891 DOI: 10.1002/mrm.28805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 12/29/2022]
Abstract
PURPOSE Benchmarking of flow and perfusion MR techniques on standardized phantoms can facilitate the use of advanced angiography and perfusion-mapping techniques across multiple sites, field strength, and vendors. Here, MRA and perfusion mapping by arterial spin labeling (ASL) using Fourier transform (FT)-based velocity-selective saturation and inversion pulse trains were evaluated on a commercial perfusion phantom. METHODS The FT velocity-selective saturation-based MRA and FT velocity-selective inversion-based ASL perfusion imaging were compared with time-of-flight and pseudo-continuous ASL at 3 T on the perfusion phantom at two controlled flow rates, 175 mL/min and 350 mL/min. Velocity-selective MRA (VSMRA) and velocity-selective ASL (VSASL) were each performed with three velocity-encoding directions: foot-head, left-right, and oblique 45°. The contrast-to-noise ratio for MRA scans and perfusion-weighted signal, as well as labeling efficiency for ASL methods, were quantified. RESULTS On this phantom with feeding tubes having only vertical and transverse flow directions, VSMRA and VSASL exhibited the dependence of velocity-encoding directions. The foot-head-encoded VSMRA and VSASL generated similar signal contrasts as time of flight and pseudo-continuous ASL for the two flow rates, respectively. The oblique 45°-encoded VSMRA yielded more uniform contrast-to-noise ratio across slices than foot-head and left-right-encoded VSMRA scans. The oblique 45°-encoded VSASL elevated labeling efficiency from 0.22-0.68 to 0.82-0.90 through more uniform labeling of the entire feeding tubes. CONCLUSION Both FT velocity-selective saturation-based VSMRA and FT velocity-selective inversion-based VSASL were characterized on a commercial perfusion phantom. Careful selection of velocity-encoding directions along the major vessels is recommended for their applications in various organs.
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Affiliation(s)
- Feng Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Dan Zhu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Hongli Fan
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Wenbo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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21
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Harteveld AA, Littooij AS, van Noesel MM, van Stralen M, Bos C. Perfusion imaging of neuroblastoma and nephroblastoma in a paediatric population using pseudo-continuous arterial spin-labelling magnetic resonance imaging. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2021; 35:235-246. [PMID: 34342775 PMCID: PMC8995293 DOI: 10.1007/s10334-021-00943-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/18/2021] [Accepted: 07/07/2021] [Indexed: 11/29/2022]
Abstract
Objectives To examine the feasibility of performing ASL-MRI in paediatric patients with solid abdominal tumours. Methods Multi-delay ASL data sets were acquired in ten paediatric patients diagnosed with either a neuroblastoma (n = 4) or nephroblastoma (n = 6) during a diagnostic MRI examination at a single visit (n = 4 at initial staging, n = 2 neuroblastoma and n = 2 nephroblastoma patients; n = 6 during follow-up, n = 2 neuroblastoma and n = 4 nephroblastoma patients). Visual evaluation and region-of-interest (ROI) analyses were performed on the processed perfusion-weighted images to assess ASL perfusion signal dynamics in the whole tumour, contralateral kidney, and tumour sub-regions with/without contrast enhancement. Results The majority of the included abdominal tumours presented with relatively low perfusion-weighted signal (PWS), especially compared with the highly perfused kidneys. Within the tumours, regions with high PWS were observed which, at short PLD, are possibly related to labelled blood inside vessels and at long PLD, reflect labelled blood accumulating inside tumour tissue over time. Conversely, comparison of ASL perfusion-weighted image findings with T1w enhancement after contrast administration showed that regions lacking contrast enhancement also were void of PWS. Discussion This pilot study demonstrates the feasibility of utilizing ASL-MRI in paediatric patients with solid abdominal tumours and provides a basis for further research on non-invasive perfusion measurements in this study population.
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Affiliation(s)
- Anita Adriaantje Harteveld
- Department of Radiology, University Medical Centre Utrecht, Utrecht University, P.O. box 85500, 3508 GA, Utrecht, The Netherlands.,Department of Radiology and Nuclear Medicine, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands
| | - Annemieke Simone Littooij
- Department of Radiology, University Medical Centre Utrecht, Utrecht University, P.O. box 85500, 3508 GA, Utrecht, The Netherlands.,Princess Máxima Centre for Paediatric Oncology, Utrecht, The Netherlands
| | | | - Marijn van Stralen
- Department of Radiology, University Medical Centre Utrecht, Utrecht University, P.O. box 85500, 3508 GA, Utrecht, The Netherlands
| | - Clemens Bos
- Department of Radiology, University Medical Centre Utrecht, Utrecht University, P.O. box 85500, 3508 GA, Utrecht, The Netherlands.
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22
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Li W, Liu D, van Zijl PCM, Qin Q. Three-dimensional whole-brain mapping of cerebral blood volume and venous cerebral blood volume using Fourier transform-based velocity-selective pulse trains. Magn Reson Med 2021; 86:1420-1433. [PMID: 33955583 DOI: 10.1002/mrm.28815] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 03/28/2021] [Accepted: 04/01/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE To develop 3D MRI methods for cerebral blood volume (CBV) and venous cerebral blood volume (vCBV) estimation with whole-brain coverage using Fourier transform-based velocity-selective (FT-VS) pulse trains. METHODS For CBV measurement, FT-VS saturation pulse trains were used to suppress static tissue, whereas CSF contamination was corrected voxel-by-voxel using a multi-readout acquisition and a fast CSF T2 scan. The vCBV mapping was achieved by inserting an arterial-nulling module that included a FT-VS inversion pulse train. Using these methods, CBV and vCBV maps were obtained on 6 healthy volunteers at 3 T. RESULTS The mean CBV and vCBV values in gray matter and white matter in different areas of the brain showed high correlation (r = 0.95 and P < .0001). The averaged CBV and vCBV values of the whole brain were 5.4 ± 0.6 mL/100 g and 2.5 ± 0.3 mL/100 g in gray matter, and 2.6 ± 0.5 mL/100 g and 1.5 ± 0.2 mL/100 g in white matter, respectively, comparable to the literature. CONCLUSION The feasibility of FT-VS-based CBV and vCBV estimation was demonstrated for 3D acquisition with large spatial coverage.
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Affiliation(s)
- Wenbo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Peter C M van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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23
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Liu D, Jiang D, Tekes A, Kulikowicz E, Martin LJ, Lee JK, Liu P, Qin Q. Multi-Parametric Evaluation of Cerebral Hemodynamics in Neonatal Piglets Using Non-Contrast-Enhanced Magnetic Resonance Imaging Methods. J Magn Reson Imaging 2021; 54:1053-1065. [PMID: 33955613 DOI: 10.1002/jmri.27638] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Disruption of brain oxygen delivery and consumption after hypoxic-ischemic injury contributes to neonatal mortality and neurological impairment. Measuring cerebral hemodynamic parameters, including cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2 ), is clinically important. PURPOSE Phase-contrast (PC), velocity-selective arterial spin labeling (VSASL), and T2 -relaxation-under-phase-contrast (TRUPC) are magnetic resonance imaging (MRI) techniques that have shown promising results in assessing cerebral hemodynamics in humans. We aimed to test their feasibility in quantifying CBF, OEF, and CMRO2 in piglets. STUDY TYPE Prospective. ANIMAL MODEL Ten neonatal piglets subacutely recovered from global hypoxia-ischemia (N = 2), excitotoxic brain injury (N = 6), or sham procedure (N = 2). FIELD STRENGTH/SEQUENCE VSASL, TRUPC, and PC MRI acquired at 3.0 T. ASSESSMENT Regional CBF was measured by VSASL. Global CBF was quantified by both PC and VSASL. TRUPC assessed OEF at the superior sagittal sinus (SSS) and internal cerebral veins (ICVs). CMRO2 was calculated from global CBF and SSS-derived OEF. End-tidal carbon dioxide (EtCO2 ) levels of the piglets were also measured. Brain damage was assessed in tissue sections postmortem by counting damaged neurons. STATISTICAL TESTS Spearman correlations were performed to evaluate associations among CBF (by PC or VSASL), OEF, CMRO2 , EtCO2 , and the pathological neuron counts. Paired t-test was used to compare OEF at SSS with OEF at ICV. RESULTS Global CBF was 32.1 ± 14.9 mL/100 g/minute and 30.9 ± 8.3 mL/100 g/minute for PC and VSASL, respectively, showing a significant correlation (r = 0.82, P < 0.05). OEF was 54.9 ± 8.8% at SSS and 46.1 ± 5.6% at ICV, showing a significant difference (P < 0.05). Global CMRO2 was 79.1 ± 26.2 μmol/100 g/minute and 77.2 ± 12.2 μmol/100 g/minute using PC and VSASL-derived CBF, respectively. EtCO2 correlated positively with PC-based CBF (r = 0.81, P < 0.05) but negatively with OEF at SSS (r = -0.84, P < 0.05). Relative CBF of subcortical brain regions and OEF at ICV did not significantly correlate, respectively, with the ratios of degenerating-to-total neurons (P = 0.30, P = 0.10). DATA CONCLUSION Non-contrast MRI can quantify cerebral hemodynamic parameters in normal and brain-injured neonatal piglets. LEVEL OF EVIDENCE 1 TECHNICAL EFFICACY STAGE: 2.
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Affiliation(s)
- Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Dengrong Jiang
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Aylin Tekes
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ewa Kulikowicz
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Lee J Martin
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jennifer K Lee
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peiying Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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24
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Liu D, Li W, Xu F, Zhu D, Shin T, Qin Q. Ensuring both velocity and spatial responses robust to B0/B1+ field inhomogeneities for velocity-selective arterial spin labeling through dynamic phase-cycling. Magn Reson Med 2021; 85:2723-2734. [PMID: 33349968 PMCID: PMC7962600 DOI: 10.1002/mrm.28622] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/15/2020] [Accepted: 11/09/2020] [Indexed: 01/22/2023]
Abstract
PURPOSE To evaluate both velocity and spatial responses of velocity-selective arterial spin labeling (VS-ASL), using velocity-insensitive and velocity-compensated waveforms for control modules, as well as a novel dynamic phase-cycling approach, at different B0 / B 1 + field inhomogeneities. METHODS In the presence of imperfect refocusing, the mechanism of phase-cycling the refocusing pulses through four dynamics was first theoretically analyzed with the conventional velocity-selective saturation (VSS) pulse train. Numerical simulations were then deployed to compare the performance of the Fourier-transform based velocity-selective inversion (FT-VSI) with these three different schemes in terms of both velocity and spatial responses under various B0 / B 1 + conditions. Phantom and human brain scans were performed to evaluate the three methods at B 1 + scales of 0.8, 1.0, and 1.2. RESULTS The simulations of FT-VSI showed that, under nonuniform B0 / B 1 + conditions, the scheme with velocity-insensitive control was susceptible to DC bias of the static spins as systematic error, while the scheme with velocity-compensated control had deteriorated velocity-selective labeling profiles and, thus, reduced labeling efficiency. Through numerical simulation, phantom scans, and brain perfusion measurements, the dynamic phase-cycling method demonstrated considerable improvements over these issues. CONCLUSION The proposed dynamic phase-cycling approach was demonstrated for the velocity-selective label and control modules with both velocity and spatial responses robust to a wide range of B0 and B 1 + field inhomogeneities.
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Affiliation(s)
- Dapeng Liu
- Department of Radiology; Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Wenbo Li
- Department of Radiology; Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Feng Xu
- Department of Radiology; Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Dan Zhu
- Department of Biomedical Engineering; Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Taehoon Shin
- Division of Mechanical and Biomedical Engineering, Ewha Womans University, Seoul, South Korea
- Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Qin Qin
- Department of Radiology; Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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25
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Zhao MY, Fan AP, Chen DYT, Sokolska MJ, Guo J, Ishii Y, Shin DD, Khalighi MM, Holley D, Halbert K, Otte A, Williams B, Rostami T, Park JH, Shen B, Zaharchuk G. Cerebrovascular reactivity measurements using simultaneous 15O-water PET and ASL MRI: Impacts of arterial transit time, labeling efficiency, and hematocrit. Neuroimage 2021; 233:117955. [PMID: 33716155 PMCID: PMC8272558 DOI: 10.1016/j.neuroimage.2021.117955] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/28/2021] [Accepted: 03/04/2021] [Indexed: 12/19/2022] Open
Abstract
Cerebrovascular reactivity (CVR) reflects the capacity of the brain to meet changing physiological demands and can predict the risk of cerebrovascular diseases. CVR can be obtained by measuring the change in cerebral blood flow (CBF) during a brain stress test where CBF is altered by a vasodilator such as acetazolamide. Although the gold standard to quantify CBF is PET imaging, the procedure is invasive and inaccessible to most patients. Arterial spin labeling (ASL) is a non-invasive and quantitative MRI method to measure CBF, and a consensus guideline has been published for the clinical application of ASL. Despite single post labeling delay (PLD) pseudo-continuous ASL (PCASL) being the recommended ASL technique for CBF quantification, it is sensitive to variations to the arterial transit time (ATT) and labeling efficiency induced by the vasodilator in CVR studies. Multi-PLD ASL controls for the changes in ATT, and velocity selective ASL is in theory insensitive to both ATT and labeling efficiency. Here we investigate CVR using simultaneous 15O-water PET and ASL MRI data from 19 healthy subjects. CVR and CBF measured by the ASL techniques were compared using PET as the reference technique. The impacts of blood T1 and labeling efficiency on ASL were assessed using individual measurements of hematocrit and flow velocity data of the carotid and vertebral arteries measured using phase-contrast MRI. We found that multi-PLD PCASL is the ASL technique most consistent with PET for CVR quantification (group mean CVR of the whole brain = 42 ± 19% and 40 ± 18% respectively). Single-PLD ASL underestimated the CVR of the whole brain significantly by 15 ± 10% compared with PET (p<0.01, paired t-test). Changes in ATT pre- and post-acetazolamide was the principal factor affecting ASL-based CVR quantification. Variations in labeling efficiency and blood T1 had negligible effects.
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Affiliation(s)
- Moss Y Zhao
- Department of Radiology, Stanford University, Stanford, CA, United States.
| | - Audrey P Fan
- Department of Biomedical Engineering, University of California Davis, Davis, CA, USA; Department of Neurology, University of California Davis, Davis, CA, USA
| | - David Yen-Ting Chen
- Department of Medical Imaging, Taipei Medical University - Shuan-Ho Hospital, New Taipei City, Taiwan; Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Magdalena J Sokolska
- Medical Physics and Biomedical Engineering, University College London Hospitals, London, United Kingdom
| | - Jia Guo
- Department of Bioengineering, University of California Riverside, Riverside, CA, United States
| | - Yosuke Ishii
- Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan
| | | | | | - Dawn Holley
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Kim Halbert
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Andrea Otte
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Brittney Williams
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Taghi Rostami
- Department of Bioengineering, Stanford University, Stanford, CA, United States
| | - Jun-Hyung Park
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Bin Shen
- Department of Radiology, Stanford University, Stanford, CA, United States
| | - Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, CA, United States.
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26
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Holmes JH, Jen ML, Eisenmenger LB, Schubert T, Turski PA, Johnson KM. Spatial dependency and the role of local susceptibility for velocity selective arterial spin labeling (VS-ASL) relative tagging efficiency using accelerated 3D radial sampling with a BIR-8 preparation. Magn Reson Med 2021; 86:293-307. [PMID: 33615527 DOI: 10.1002/mrm.28726] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 01/17/2021] [Accepted: 01/20/2021] [Indexed: 01/31/2023]
Abstract
PURPOSE Velocity selective arterial spin labeling (VS-ASL) is a promising approach for non-contrast perfusion imaging that provides robustness to vascular geometry and transit times; however, VS-ASL assumes spatially uniform tagging efficiency. This work presents a mapping approach to investigate VS-ASL relative tagging efficiency including the impact of local susceptibility effects on a BIR-8 preparation. METHODS Numerical simulations of tagging efficiency were performed to evaluate sensitivity to regionally varying local susceptibility gradients and blood velocity. Tagging efficiency mapping was performed in susceptibility phantoms and healthy human subjects (N = 7) using a VS-ASL preparation module followed by a short, high spatial resolution 3D radial-based image acquisition. Tagging efficiency maps were compared to 4D-flow, B1 , and B0 maps acquired in the same imaging session for six of the seven subjects. RESULTS Numerical simulations were found to predict reduced tagging efficiency with the combination of high blood velocity and local gradient fields. Phantom experiments corroborated numerical results. Relative efficiency mapping in normal volunteers showed unique efficiency patterns depending on individual subject anatomy and physiology. Uniform tagging efficiency was generally observed in vivo, but reduced efficiency was noted in regions of high blood velocity and local susceptibility gradients. CONCLUSION We demonstrate an approach to map the relative tagging efficiency and show application of this methodology to a novel BIR-8 preparation recently proposed in the literature. We present results showing rapid flow in the presence of local susceptibility gradients can lead to complicated signal modulations in both tag and control images and reduced tagging efficiency.
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Affiliation(s)
- James H Holmes
- Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Mu-Lan Jen
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Laura B Eisenmenger
- Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Tilman Schubert
- Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Neuroradiology, University Hospital Zurich, Zurich, Switzerland
| | - Patrick A Turski
- Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kevin M Johnson
- Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
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27
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Bones IK, Franklin SL, Harteveld AA, van Osch MJP, Schmid S, Hendrikse J, Moonen C, van Stralen M, Bos C. Exploring label dynamics of velocity-selective arterial spin labeling in the kidney. Magn Reson Med 2021; 86:131-142. [PMID: 33538350 PMCID: PMC8048977 DOI: 10.1002/mrm.28683] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/07/2020] [Accepted: 12/24/2020] [Indexed: 12/13/2022]
Abstract
Purpose Velocity‐selective arterial spin labeling (VSASL) has been proposed for renal perfusion imaging to mitigate planning challenges and effects of arterial transit time (ATT) uncertainties. In VSASL, label generation may shift in the vascular tree as a function of cutoff velocity. Here, we investigate label dynamics and especially the ATT of renal VSASL and compared it with a spatially selective pulsed arterial spin labeling technique, flow alternating inversion recovery (FAIR). Methods Arterial spin labeling data were acquired in 7 subjects, using free‐breathing dual VSASL and FAIR with five postlabeling delays: 400, 800, 1200, 2000, and 2600 ms. The VSASL measurements were acquired with cutoff velocities of 5, 10, and 15 cm/s, with anterior–posterior velocity‐encoding direction. Cortical perfusion‐weighted signal, temporal SNR, quantified renal blood flow, and arterial transit time were reported. Results In contrast to FAIR, renal VSASL already showed fairly high signal at the earliest postlabeling delays, for all cutoff velocities. The highest VSASL signal and temporal SNR was obtained with a cutoff velocity of 10 cm/s at postlabeling delay = 800 ms, which was earlier than for FAIR at 1200 ms. Fitted ATT on VSASL was ≤ 0 ms, indicating ATT insensitivity, which was shorter than for FAIR (189 ± 79 ms, P < .05). Finally, the average cortical renal blood flow measured with cutoff velocities of 5 cm/s (398 ± 84 mL/min/100 g) and 10 cm/s (472 ± 160 mL/min/100 g) were similar to renal blood flow measured with FAIR (441 ± 84 mL/min/100 g) (P > .05) with good correlations on subject level. Conclusion Velocity‐selective arterial spin labeling in the kidney reduces ATT sensitivity compared with the recommended pulsed arterial spin labeling method, as well as if cutoff velocity is increased to reduce spurious labeling due to motion. Thus, VSASL has potential as a method for time‐efficient, single‐time‐point, free‐breathing renal perfusion measurements, despite lower tSNR than FAIR.
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Affiliation(s)
- Isabell K Bones
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Suzanne L Franklin
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands.,C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Anita A Harteveld
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands.,Department of Radiology and Nuclear Medicine, Erasmus MC University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Matthias J P van Osch
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Sophie Schmid
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Chrit Moonen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Marijn van Stralen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Clemens Bos
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
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28
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Franklin SL, Bones IK, Harteveld AA, Hirschler L, van Stralen M, Qin Q, de Boer A, Hoogduin JM, Bos C, van Osch MJP, Schmid S. Multi-organ comparison of flow-based arterial spin labeling techniques: Spatially non-selective labeling for cerebral and renal perfusion imaging. Magn Reson Med 2020; 85:2580-2594. [PMID: 33251644 PMCID: PMC7898485 DOI: 10.1002/mrm.28603] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 09/21/2020] [Accepted: 10/26/2020] [Indexed: 12/12/2022]
Abstract
Purpose Flow‐based arterial spin labeling (ASL) techniques provide a transit‐time insensitive alternative to the more conventional spatially selective ASL techniques. However, it is not clear which flow‐based ASL technique performs best and also, how these techniques perform outside the brain (taking into account eg, flow‐dynamics, field‐inhomogeneity, and organ motion). In the current study we aimed to compare 4 flow‐based ASL techniques (ie, velocity selective ASL, acceleration selective ASL, multiple velocity selective saturation ASL, and velocity selective inversion prepared ASL [VSI‐ASL]) to the current spatially selective reference techniques in brain (ie, pseudo‐continuous ASL [pCASL]) and kidney (ie, pCASL and flow alternating inversion recovery [FAIR]). Methods Brain (n = 5) and kidney (n = 6) scans were performed in healthy subjects at 3T. Perfusion‐weighted signal (PWS) maps were generated and ASL techniques were compared based on temporal SNR (tSNR), sensitivity to perfusion changes using a visual stimulus (brain) and robustness to respiratory motion by comparing scans acquired in paced‐breathing and free‐breathing (kidney). Results In brain, all flow‐based ASL techniques showed similar tSNR as pCASL, but only VSI‐ASL showed similar sensitivity to perfusion changes. In kidney, all flow‐based ASL techniques had comparable tSNR, although all lower than FAIR. In addition, VSI‐ASL showed a sensitivity to B1‐inhomogeneity. All ASL techniques were relatively robust to respiratory motion. Conclusion In both brain and kidney, flow‐based ASL techniques provide a planning‐free and transit‐time insensitive alternative to spatially selective ASL techniques. VSI‐ASL shows the most potential overall, showing similar performance as the golden standard pCASL in brain. However, in kidney, a reduction of B1‐sensitivity of VSI‐ASL is necessary to match the performance of FAIR.
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Affiliation(s)
- Suzanne L Franklin
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.,Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands.,Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands
| | - Isabell K Bones
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Anita A Harteveld
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Lydiane Hirschler
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.,Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands
| | - Marijn van Stralen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Anneloes de Boer
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Johannes M Hoogduin
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Clemens Bos
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Matthias J P van Osch
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.,Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands
| | - Sophie Schmid
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.,Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands
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29
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Guo J, Gong E, Fan AP, Goubran M, Khalighi MM, Zaharchuk G. Predicting 15O-Water PET cerebral blood flow maps from multi-contrast MRI using a deep convolutional neural network with evaluation of training cohort bias. J Cereb Blood Flow Metab 2020; 40:2240-2253. [PMID: 31722599 PMCID: PMC7585922 DOI: 10.1177/0271678x19888123] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
To improve the quality of MRI-based cerebral blood flow (CBF) measurements, a deep convolutional neural network (dCNN) was trained to combine single- and multi-delay arterial spin labeling (ASL) and structural images to predict gold-standard 15O-water PET CBF images obtained on a simultaneous PET/MRI scanner. The dCNN was trained and tested on 64 scans in 16 healthy controls (HC) and 16 cerebrovascular disease patients (PT) with 4-fold cross-validation. Fidelity to the PET CBF images and the effects of bias due to training on different cohorts were examined. The dCNN significantly improved CBF image quality compared with ASL alone (mean ± standard deviation): structural similarity index (0.854 ± 0.036 vs. 0.743 ± 0.045 [single-delay] and 0.732 ± 0.041 [multi-delay], P < 0.0001); normalized root mean squared error (0.209 ± 0.039 vs. 0.326 ± 0.050 [single-delay] and 0.344 ± 0.055 [multi-delay], P < 0.0001). The dCNN also yielded mean CBF with reduced estimation error in both HC and PT (P < 0.001), and demonstrated better correlation with PET. The dCNN trained with the mixed HC and PT cohort performed the best. The results also suggested that models should be trained on cases representative of the target population.
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Affiliation(s)
- Jia Guo
- Department of Radiology, Stanford University, Stanford, CA, USA.,Department of Bioengineering, University of California Riverside, Riverside, CA, USA
| | - Enhao Gong
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA.,Subtle Medical Inc., Menlo Park, CA, USA
| | - Audrey P Fan
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Maged Goubran
- Department of Radiology, Stanford University, Stanford, CA, USA
| | | | - Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, CA, USA
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Guo J, Das S, Hernandez-Garcia L. Comparison of velocity-selective arterial spin labeling schemes. Magn Reson Med 2020; 85:2027-2039. [PMID: 33128484 DOI: 10.1002/mrm.28572] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/09/2020] [Accepted: 10/06/2020] [Indexed: 12/22/2022]
Abstract
PURPOSE In velocity-selective (VS) arterial spin labeling, strategies using multiple saturation modules or using VS inversion (VSI) pulse can provide improved SNR efficiency compared to the original labeling scheme using one VS saturation (VSS) module. Their performance improvement, however, has not been directly compared. METHODS Different VS labeling schemes were evaluated by Bloch simulation for their SNR efficiency, eddy current sensitivity, and robustness against B1 and B0 variation. These schemes included dual-module double-refocused hyperbolic secant and symmetric 8-segment B1 -insensitive rotation (sBIR8-) VSS pulses, the original and modified Fourier transform-based VSI pulses. A subset of the labeling schemes was examined further in phantom and in vivo experiments for their eddy current sensitivity and SNR performance. An additional sBIR8-VSS with a built-in inversion (sBIR8-VSS-inversion) was evaluated for the effects of partial background suppression to allow a fairer comparison to VSI. RESULTS According to the simulations, the sBIR8-VSS was the most robust against field imperfections and had similarly high SNR efficiency (dual-module, dual-sBIR8-VSS) compared with the best VSI pulse (sinc-modulated, sinc-VSI). These were confirmed by the phantom and in vivo data. Without additional background suppression, the sinc-VSI pulses had the highest temporal SNR, closely followed by the sBIR8-VSS-inversion pulse, both benefited from partial background suppression effects. CONCLUSION Dual-sBIR8-VSS and sinc-VSI measured the highest SNR efficiency among the VS labeling schemes. Dual-sBIR8-VSS was the most robust against field imperfections, whereas sinc-VSI may provide a higher SNR efficiency if its immunity to field imperfections can be improved.
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Affiliation(s)
- Jia Guo
- Department of Bioengineering, University of California Riverside, Riverside, California, USA
| | - Shaurov Das
- Department of Bioengineering, University of California Riverside, Riverside, California, USA
| | - Luis Hernandez-Garcia
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA.,FMRI Laboratory, University of Michigan, Ann Arbor, Michigan, USA
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Lee H, Wehrli FW. Venous cerebral blood volume mapping in the whole brain using venous-spin-labeled 3D turbo spin echo. Magn Reson Med 2020; 84:1991-2003. [PMID: 32243708 DOI: 10.1002/mrm.28262] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/27/2020] [Accepted: 02/29/2020] [Indexed: 11/12/2022]
Abstract
PURPOSE Venous cerebral blood volume (CBVv ) is a major contributor to BOLD contrast, and therefore is an important parameter for understanding the underlying mechanism. Here, we propose a velocity-selective venous spin labeling (VS-VSL)-prepared 3D turbo spin echo pulse sequence for whole-brain baseline CBVv mapping. METHODS Unlike previous CBVv measurement techniques that exploit the interrelationship between BOLD signals and CBVv , in the proposed VS-VSL technique both arterial blood and cerebrospinal fluid (CSF) signals were suppressed before the VS pulse train for exclusive labeling of venous blood, while a single-slab 3D turbo spin echo readout was used because of its relative immunity to magnetic field variations. Furthermore, two approximations were made to the VS-VSL signal model for simplified derivation of CBVv . In vivo studies were performed at 3T field strength in 8 healthy subjects. The performance of the proposed VS-VSL method in baseline CBVv estimation was first evaluated in comparison to the existing, hyperoxia-based method. Then, data were also acquired using VS-VSL under hypercapnic and hyperoxic gas breathing challenges for further validation of the technique. RESULTS The proposed technique yielded physiologically plausible baseline CBVv values, and when compared with the hyperoxia-based method, showed no statistical difference. Furthermore, data acquired using VS-VSL yielded average CBVv of 2.89%/1.78%, 3.71%/2.29%, and 2.88%/1.76% for baseline, hypercapnia, and hyperoxia, respectively, in gray/white matter regions. As expected, hyperoxia had negligible effect (P > .8), whereas hypercapnia demonstrated vasodilation (P << .01). CONCLUSION Upon further validation of the quantification model, the method is expected to have merit for 3D CBVv measurements across the entire brain.
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Affiliation(s)
- Hyunyeol Lee
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Felix W Wehrli
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Zhu D, Li W, Liu D, Liu G, Pei Y, Shin T, Sedaghat F, Qin Q. Non-contrast-enhanced abdominal MRA at 3 T using velocity-selective pulse trains. Magn Reson Med 2020; 84:1173-1183. [PMID: 32017173 PMCID: PMC7263981 DOI: 10.1002/mrm.28187] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 12/16/2019] [Accepted: 01/07/2020] [Indexed: 11/09/2022]
Abstract
PURPOSE Most existing non-contrast-enhanced methods for abdominal MR arteriography rely on a spatially selective inversion (SSI) pulse with a delay to null both static tissue and venous blood, and are limited to small spatial coverage due to the sensitivity to slow arterial inflow. Velocity-selective inversion (VSI) based approach has been shown to preserve the arterial blood inside the imaging volume at 1.5 T. Recently, velocity-selective saturation (VSS) pulse trains were applied to suppress the static tissue and have been combined with SSI pulses for cerebral MR arteriography at 3 T. The aim of this study is to construct an abdominal MRA protocol with large spatial coverage at 3 T using advanced velocity-selective pulse trains. METHODS Multiple velocity-selective MRA protocols with different sequence modules and 3D acquisition methods were evaluated. Sequences using VSS only as well as SSI+VSS and VSI+VSS preparations were then compared among a group of healthy young and middle-aged volunteers. Using MRA without any preparations as reference, relative signal ratios and relative contrast ratios of different vascular segments were quantitatively analyzed. RESULTS Both SSI+VSS and VSI+VSS arteriograms achieved high artery-to-tissue and artery-to-vein relative contrast ratios above aortic bifurcation. The SSI+VSS sequence yielded lower signal at the bilateral iliac arteries than VSI+VSS, reflecting the benefit of the VSI preparation for imaging the distal branches. CONCLUSION The feasibility of noncontrast 3D MR abdominal arteriography was demonstrated on healthy volunteers using a combination of VSS pulse trains and SSI or VSI pulse.
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Affiliation(s)
- Dan Zhu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Wenbo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Guanshu Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
| | - Yigang Pei
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
- Department of Radiology, Xiangya Hospital, Central South University, Changsha, China
| | - Taehoon Shin
- Division of Mechanical and Biomedical Engineering, Ewha Woman’s University, Seoul, South Korea
- Department of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Farzad Sedaghat
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
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Liu D, Xu F, Li W, van Zijl PC, Lin DD, Qin Q. Improved velocity-selective-inversion arterial spin labeling for cerebral blood flow mapping with 3D acquisition. Magn Reson Med 2020; 84:2512-2522. [PMID: 32406137 DOI: 10.1002/mrm.28310] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 03/17/2020] [Accepted: 04/15/2020] [Indexed: 11/12/2022]
Abstract
PURPOSE To further optimize the velocity-selective arterial spin labeling (VSASL) sequence utilizing a Fourier-transform based velocity-selective inversion (FT-VSI) pulse train, and to evaluate its utility for 3D mapping of cerebral blood flow (CBF) with a gradient- and spin-echo (GRASE) readout. METHODS First, numerical simulations and phantom experiments were done to test the susceptibility to eddy currents and B1 field inhomogeneities for FT-VSI pulse trains with block and composite refocusing pulses. Second, the choices of the post-labeling delay (PLD) for FT-VSI prepared 3D VSASL were evaluated for the sensitivity to perfusion signal. The study was conducted among a young-age and a middle-age group at 3T. Both signal-to-noise ratio (SNR) and CBF were quantitatively compared with pseudo-continuous ASL (PCASL). The optimized 3D VSI-ASL was also qualitatively compared with PCASL in a whole-brain coverage among two healthy volunteers and a brain tumor patient. RESULTS The simulations and phantom test showed that composite refocusing pulses are more robust to both eddy-currents and B1 field inhomogeneities than block pulses. 3D VSASL images with FT-VSI preparation were acquired over a range of PLDs and PLD = 1.2 s was selected for its higher perfusion signal. FT-VSI labeling produced quantitative CBF maps with 27% higher SNR in gray matter compared to PCASL. 3D whole-brain CBF mapping using VSI-ASL were comparable to the corresponding PCASL results. CONCLUSION FT-VSI with 3D-GRASE readout was successfully implemented and showed higher sensitivity to perfusion signal than PCASL for both young and middle-aged healthy volunteers.
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Affiliation(s)
- Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Feng Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Wenbo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Peter C van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Doris D Lin
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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Narayanan S, Schmithorst V, Panigrahy A. Arterial Spin Labeling in Pediatric Neuroimaging. Semin Pediatr Neurol 2020; 33:100799. [PMID: 32331614 DOI: 10.1016/j.spen.2020.100799] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Perfusion imaging using arterial spin labeling noninvasively evaluates cerebral blood flow utilizing arterial blood water as endogenous tracer. It does not require the need of radiotracer or intravenous contrast and offers unique complimentary information in the imaging of pediatric brain. Common clinical applications include neonatal hypoxic ischemic encephalopathy, pediatric stroke and vascular malformations, epilepsy and brain tumors. Future applications may include evaluation of silent ischemia in sickle cell patients, monitor changes in intracranial pressure in hydrocephalus, provide additional insights in nonaccidental trauma and chronic traumatic brain injury (TBI) and in functional Magnetic resonance imaging (MRI). The purpose of this review article is to evaluate the technical considerations including pitfalls, physiological variations, clinical applications and future directions of arterial spin labeling imaging.
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Affiliation(s)
- Srikala Narayanan
- Children's Hospital of Pittsburgh of UPMC, Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA.
| | - Vincent Schmithorst
- Children's Hospital of Pittsburgh of UPMC, Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Ashok Panigrahy
- John F. Caffey Endowed Chair in Pediatric Radiology, Children's Hospital of Pittsburgh of UPMC, Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA
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Bones IK, Franklin SL, Harteveld AA, van Osch MJP, Hendrikse J, Moonen C, van Stralen M, Bos C. Influence of labeling parameters and respiratory motion on velocity-selective arterial spin labeling for renal perfusion imaging. Magn Reson Med 2020; 84:1919-1932. [PMID: 32180263 PMCID: PMC7384062 DOI: 10.1002/mrm.28252] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 01/15/2020] [Accepted: 02/19/2020] [Indexed: 12/12/2022]
Abstract
Purpose Arterial transit time uncertainties and challenges during planning are potential issues for renal perfusion measurement using spatially selective arterial spin labeling techniques. To mitigate these potential issues, a spatially non‐selective technique, such as velocity‐selective arterial spin labeling (VSASL), could be an alternative. This article explores the influence of VSASL sequence parameters and respiratory induced motion on VS‐label generation. Methods VSASL data were acquired in human subjects (n = 15), with both single and dual labeling, during paced‐breathing, while essential sequence parameters were systematically varied; (1) cutoff velocity, (2) labeling gradient orientation and (3) post‐labeling delay (PLD). Pseudo‐continuous ASL was acquired as a spatially selective reference. In an additional free‐breathing single VSASL experiment (n = 9) we investigated respiratory motion influence on VS‐labeling. Absolute renal blood flow (RBF), perfusion weighted signal (PWS), and temporal signal‐to‐noise ratio (tSNR) were determined. Results (1) With decreasing cutoff velocity, tSNR and PWS increased. However, undesired tissue labeling occurred at low cutoff velocities (≤ 5.4 cm/s). (2) Labeling gradient orientation had little effect on tSNR and PWS. (3) For single VSASL high signal appeared in the kidney pedicle at PLD < 800 ms, and tSNR and PWS decreased with increasing PLD. For dual VSASL, maximum tSNR occurred at PLD = 1200 ms. Average cortical RBF measured with dual VSASL (264 ± 34 mL/min/100 g) at a cutoff velocity of 5.4 cm/s, and feet‐head labeling was slightly lower than with pseudo‐continuous ASL (283 ± 55 mL/min/100 g). Conclusion With well‐chosen sequence parameters, tissue labeling induced by respiratory motion can be minimized, allowing to obtain good quality RBF maps using planning‐free labeling with dual VSASL.
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Affiliation(s)
- Isabell K Bones
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Suzanne L Franklin
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands.,C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Anita A Harteveld
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Matthias J P van Osch
- C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Chrit Moonen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Marijn van Stralen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Clemens Bos
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, the Netherlands
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Landes V, Javed A, Jao T, Qin Q, Nayak K. Improved velocity-selective labeling pulses for myocardial ASL. Magn Reson Med 2020; 84:1909-1918. [PMID: 32173909 DOI: 10.1002/mrm.28253] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/19/2020] [Accepted: 02/19/2020] [Indexed: 12/23/2022]
Abstract
PURPOSE To develop and evaluate an improved velocity-selective (VS) labeling pulse for myocardial arterial spin labeling (ASL) perfusion imaging that addresses two limitations of current pulses: (1) spurious labeling of moving myocardium and (2) low labeling efficiency. METHODS The proposed myocardial VSASL labeling pulse is designed using a Fourier Transform based Velocity-Selective labeling pulse train. The pulse utilizes bipolar velocity-encoding gradients, a 9-tap velocity-encoding envelope, and double-refocusing pulses with Malcolm Levitt phase cycling. Amplitudes of the velocity-encoding envelope were optimized to minimize the labeling of myocardial velocities during stable diastole (±2-3 cm/s) and maximize the labeling of coronary velocities (10-130 cm/s during rest/stress or 10-70 cm/s during rest). Myocardial ASL experiments were performed in seven healthy subjects using the previously developed VS-ASL protocol by Jao et al with the two proposed VS pulses and original VS pulse. Myocardial ASL experiments were also performed using FAIR ASL. Myocardial perfusion and physiological noise (PN) were evaluated and compared. RESULTS Bloch simulations of the first and second proposed pulses show <2% labeling over ±3 cm/s and ±2 cm/s, respectively. Bloch simulations also show the mean labeling efficiency of arterial blood is 1.23 over the relevant coronary arterial ranges. In-vivo VSASL experiments show the proposed pulses provided comparable measurements to FAIR ASL and reduced TSNR in 5 of 7 subjects compared to the original VS pulse. CONCLUSION We demonstrate an improved VS labeling pulse specifically for myocardial ASL perfusion imaging to reduce spurious labeling of moving myocardium and PN.
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Affiliation(s)
- Vanessa Landes
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angles, CA, USA
| | - Ahsan Javed
- Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, Los Angles, CA, USA
| | - Terrence Jao
- Keck School of Medicine, University of Southern California, Los Angles, CA, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, John Hopkins University School of Medicine, Baltimore, MD, USA.,F.M. Kirby Research Center for Functional Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Krishna Nayak
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angles, CA, USA.,Ming Hsieh Department of Electrical and Computer Engineering, Viterbi School of Engineering, University of Southern California, Los Angles, CA, USA
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Franklin SL, Schmid S, Bos C, van Osch MJP. Influence of the cardiac cycle on velocity selective and acceleration selective arterial spin labeling. Magn Reson Med 2019; 83:872-882. [PMID: 31483531 PMCID: PMC6900074 DOI: 10.1002/mrm.27973] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/03/2019] [Accepted: 08/06/2019] [Indexed: 12/23/2022]
Abstract
Purpose In this study, the influence of the cardiac cycle on the amount of label produced by a velocity‐selective (VSASL) and acceleration‐selective arterial spin labeling (AccASL) module was investigated. Methods A short‐PLD sequence was developed where a single VSASL‐ or AccASL‐module was preceded by pCASL labeling to isolate the arterial blood pool. ASL subtraction was performed with label/control images with similar cardiac phase and time‐of‐measurement, followed by retrospective binning in 10 cardiac phase bins. ASL signal variation over the heart cycle was evaluated and tested for significance using a permutation test. Results VSASL and AccASL showed significant arterial signal fluctuations over the cardiac cycle of up to ~36% and ~64%, respectively, mainly in areas containing large arteries. pCASL also showed significant signal fluctuations, of up to ~25% in arteries. Raw label/control images confirmed that the observed signal fluctuations were caused by the amount of label produced during the cardiac cycle, rather than inflow‐effects, because the raw images did not all show equal cardiac phase dependence. No significant effects of the cardiac cycle were found on the gray matter ASL‐signal. Conclusion Significant influence of the cardiac cycle on the generated label was found for spatially nonselective ASL‐sequences. Hence, to become independent of the cardiac cycle, sufficient averages need to be taken. Alternatively, these findings could be highly interesting for the purpose of quantifying pulsatility more distally in the vascular tree.
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Affiliation(s)
- Suzanne L Franklin
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands.,Center for Image Sciences, University Medical Centre Utrecht, Utrecht, The Netherlands.,Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands
| | - Sophie Schmid
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands.,Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands
| | - Clemens Bos
- Center for Image Sciences, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Matthias J P van Osch
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, The Netherlands.,Leiden Institute for Brain and Cognition, Leiden University, Leiden, The Netherlands
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van Zijl P, Knutsson L. In vivo magnetic resonance imaging and spectroscopy. Technological advances and opportunities for applications continue to abound. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 306:55-65. [PMID: 31377150 PMCID: PMC6703925 DOI: 10.1016/j.jmr.2019.07.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 06/19/2019] [Accepted: 07/08/2019] [Indexed: 05/07/2023]
Abstract
Over the past decades, the field of in vivo magnetic resonance (MR) has built up an impressive repertoire of data acquisition and analysis technologies for anatomical, functional, physiological, and molecular imaging, the description of which requires many book volumes. As such it is impossible for a few authors to have an authoritative overview of the field and for a brief article to be inclusive. We will therefore focus mainly on data acquisition and attempt to give some insight into the principles underlying current advanced methods in the field and the potential for further innovation. In our view, the foreseeable future is expected to show continued rapid progress, for instance in imaging of microscopic tissue properties in vivo, assessment of functional and anatomical connectivity, higher resolution physiologic and metabolic imaging, and even imaging of receptor binding. In addition, acquisition speed and information content will continue to increase due to the continuous development of approaches for parallel imaging (including simultaneous multi-slice imaging), compressed sensing, and MRI fingerprinting. Finally, artificial intelligence approaches are becoming more realistic and will have a tremendous effect on both acquisition and analysis strategies. Together, these developments will continue to provide opportunity for scientific discovery and, in combination with large data sets from other fields such as genomics, allow the ultimate realization of precision medicine in the clinic.
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Affiliation(s)
- Peter van Zijl
- Department of Radiology, Johns Hopkins University, F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| | - Linda Knutsson
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
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Abstract
Arterial Spin Labeling (ASL) is a perfusion-based functional magnetic resonance imaging technique that uses water in arterial blood as a freely diffusible tracer to measure regional cerebral blood flow (rCBF) noninvasively. To date its application to the study of pain has been relatively limited. Yet, ASL possesses key features that make it uniquely positioned to study pain in certain paradigms. For instance, ASL is sensitive to very slowly fluctuating brain signals (in the order of minutes or longer). This characteristic makes ASL particularly suitable to the evaluation of brain mechanisms of tonic experimental, post-surgical and ongoing/or continuously varying pain in chronic or acute pain conditions (whereas BOLD fMRI is better suited to detect brain responses to short-lasting or phasic/evoked pain). Unlike positron emission tomography or other perfusion techniques, ASL allows the estimation of rCBF without requiring the administration of radioligands or contrast agents. Thus, ASL is well suited for within-subject longitudinal designs (e.g., to study evolution of pain states over time, or of treatment effects in clinical trials). ASL is also highly versatile, allowing for novel paradigms exploring a flexible array of pain states, plus it can be used to simultaneously estimate not only pain-related alterations in perfusion but also functional connectivity. In conclusion, ASL can be successfully applied in pain paradigms that would be either challenging or impossible to implement using other techniques. Particularly when used in concert with other neuroimaging techniques, ASL can be a powerful tool in the pain imager's toolbox.
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Qin Q, Qu Y, Li W, Liu D, Shin T, Zhao Y, Lin DD, van Zijl PC, Wen Z. Cerebral blood volume mapping using Fourier-transform-based velocity-selective saturation pulse trains. Magn Reson Med 2019; 81:3544-3554. [PMID: 30737847 PMCID: PMC6820852 DOI: 10.1002/mrm.27668] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/28/2018] [Accepted: 12/30/2018] [Indexed: 12/21/2022]
Abstract
PURPOSE Velocity-selective saturation (VSS) pulse trains provide a viable alternative to the spatially selective methods for measuring cerebral blood volume (CBV) by reducing the sensitivity to arterial transit time. This study is to compare the Fourier-transform-based velocity-selective saturation (FT-VSS) pulse trains with the conventional flow-dephasing VSS techniques for CBV quantification. METHODS The proposed FT-VSS label and control modules were compared with VSS pulse trains utilizing double refocused hyperbolic tangent (DRHT) and 8-segment B1-insensitive rotation (BIR-8). This was done using both numerical simulations and phantom studies to evaluate their sensitivities to gradient imperfections such as eddy currents. DRHT, BIR-8, and FT-VSS prepared CBV mapping was further compared for velocity-encoding gradients along 3 orthogonal directions in healthy subjects at 3T. RESULTS The phantom studies exhibited more consistent immunity to gradient imperfections for the utilized FT-VSS pulse trains. Compared to DRHT and BIR-8, FT-VSS delivered more robust CBV results across the 3 VS encoding directions with significantly reduced artifacts along the superior-inferior direction and improved temporal signal-to-noise ratio (SNR) values. Average CBV values obtained from FT-VSS based sequences were 5.3 mL/100 g for gray matter and 2.3 mL/100 g for white matter, comparable to literature expectations. CONCLUSION Absolute CBV quantification utilizing advanced FT-VSS pulse trains had several advantages over the existing approaches using flow-dephasing VSS modules. A greater immunity to gradient imperfections and the concurrent tissue background suppression of FT-VSS pulse trains enabled more robust CBV measurements and higher SNR than the conventional VSS pulse trains.
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Affiliation(s)
- Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Yaoming Qu
- Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
| | - Wenbo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Dapeng Liu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Taehoon Shin
- Division of Mechanical and Biomedical Engineering, Ewha Womans University, Seoul, South Korea
- Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | | | - Doris D. Lin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Peter C.M. van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Zhibo Wen
- Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China
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Hernandez-Garcia L, Lahiri A, Schollenberger J. Recent progress in ASL. Neuroimage 2019; 187:3-16. [PMID: 29305164 PMCID: PMC6030511 DOI: 10.1016/j.neuroimage.2017.12.095] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 12/21/2017] [Accepted: 12/30/2017] [Indexed: 11/26/2022] Open
Abstract
This article aims to provide the reader with an overview of recent developments in Arterial Spin Labeling (ASL) MRI techniques. A great deal of progress has been made in recent years in terms of the SNR and acquisition speed. New strategies have been introduced to improve labeling efficiency, reduce artefacts, and estimate other relevant physiological parameters besides perfusion. As a result, ASL techniques has become a reliable workhorse for researchers as well as clinicians. After a brief overview of the technique's fundamentals, this article will review new trends and variants in ASL including vascular territory mapping and velocity selective ASL, as well as arterial blood volume imaging techniques. This article will also review recent processing techniques to reduce partial volume effects and physiological noise. Next the article will examine how ASL techniques can be leveraged to calculate additional physiological parameters beyond perfusion and finally, it will review a few recent applications of ASL in the literature.
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Affiliation(s)
| | - Anish Lahiri
- FMRI Laboratory, University of Michigan, United States
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42
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Li Y, Liu P, Li Y, Fan H, Su P, Peng SL, Park DC, Rodrigue KM, Jiang H, Faria AV, Ceritoglu C, Miller M, Mori S, Lu H. ASL-MRICloud: An online tool for the processing of ASL MRI data. NMR IN BIOMEDICINE 2019; 32:e4051. [PMID: 30588671 PMCID: PMC6324946 DOI: 10.1002/nbm.4051] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/27/2018] [Accepted: 11/13/2018] [Indexed: 05/30/2023]
Abstract
Arterial spin labeling (ASL) MRI is increasingly used in research and clinical settings. The purpose of this work is to develop a cloud-based tool for ASL data processing, referred to as ASL-MRICloud, which may be useful to the MRI community. In contrast to existing ASL toolboxes, which are based on software installation on the user's local computer, ASL-MRICloud uses a web browser for data upload and results download, and the computation is performed on the remote server. As such, this tool is independent of the user's operating system, software version, and CPU speed. The ASL-MRICloud tool was implemented to be compatible with data acquired by scanners from all major MRI manufacturers, is capable of processing several common forms of ASL, including pseudo-continuous ASL and pulsed ASL, and can process single-delay and multi-delay ASL data. The outputs of ASL-MRICloud include absolute and relative values of cerebral blood flow, arterial transit time, voxel-wise masks indicating regions with potential hyper-perfusion and hypo-perfusion, and an image quality index. The ASL tool is also integrated with a T1 -based brain segmentation and normalization tool in MRICloud to allow generation of parametric maps in standard brain space as well as region-of-interest values. The tool was tested on a large data set containing 309 ASL scans as well as on publicly available ASL data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study.
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Affiliation(s)
- Yang Li
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Peiying Liu
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yue Li
- AnatomyWorks, LLC, Baltimore, MD, USA
| | - Hongli Fan
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Pan Su
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shin-Lei Peng
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung City, Taiwan
| | - Denise C. Park
- Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Karen M. Rodrigue
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hangyi Jiang
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Andreia V. Faria
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Can Ceritoglu
- Center for Imaging Science, Johns Hopkins University, Baltimore, MD, USA
| | - Michael Miller
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
- Center for Imaging Science, Johns Hopkins University, Baltimore, MD, USA
| | - Susumu Mori
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
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Knutsson L, Xu J, Ahlgren A, van Zijl P. CEST, ASL, and magnetization transfer contrast: How similar pulse sequences detect different phenomena. Magn Reson Med 2018; 80:1320-1340. [PMID: 29845640 PMCID: PMC6097930 DOI: 10.1002/mrm.27341] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 04/10/2018] [Accepted: 04/11/2018] [Indexed: 12/28/2022]
Abstract
Chemical exchange saturation transfer (CEST), arterial spin labeling (ASL), and magnetization transfer contrast (MTC) methods generate different contrasts for MRI. However, they share many similarities in terms of pulse sequences and mechanistic principles. They all use RF pulse preparation schemes to label the longitudinal magnetization of certain proton pools and follow the delivery and transfer of this magnetic label to a water proton pool in a tissue region of interest, where it accumulates and can be detected using any imaging sequence. Due to the versatility of MRI, differences in spectral, spatial or motional selectivity of these schemes can be exploited to achieve pool specificity, such as for arterial water protons in ASL, protons on solute molecules in CEST, and protons on semi-solid cell structures in MTC. Timing of these sequences can be used to optimize for the rate of a particular delivery and/or exchange transfer process, for instance, between different tissue compartments (ASL) or between tissue molecules (CEST/MTC). In this review, magnetic labeling strategies for ASL and the corresponding CEST and MTC pulse sequences are compared, including continuous labeling, single-pulse labeling, and multi-pulse labeling. Insight into the similarities and differences among these techniques is important not only to comprehend the mechanisms and confounds of the contrasts they generate, but also to stimulate the development of new MRI techniques to improve these contrasts or to reduce their interference. This, in turn, should benefit many possible applications in the fields of physiological and molecular imaging and spectroscopy.
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Affiliation(s)
- L Knutsson
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - J Xu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - A Ahlgren
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - P.C.M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
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Hernandez-Garcia L, Nielsen JF, Noll DC. Improved sensitivity and temporal resolution in perfusion FMRI using velocity selective inversion ASL. Magn Reson Med 2018; 81:1004-1015. [PMID: 30187951 DOI: 10.1002/mrm.27461] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/29/2018] [Accepted: 06/30/2018] [Indexed: 12/19/2022]
Abstract
PURPOSE This work aims to investigate the utility of velocity selective inversion pulses for perfusion weighted functional MRI. METHODS Tracer kinetic properties of velocity selective inversion (VSI) pulses as an input function for an arterial spin labeling (ASL) experiment were characterized in a group of healthy participants. Numerical simulations were conducted to search for a robust set of timing parameters for FMRI time series acquisition with maximal signal to noise ratio efficiency. The performance of three VSI pulse sequences with different timing parameters was compared with a pseudocontinuous ASL sequence in a simple FMRI experiment conducted on healthy participants. RESULTS The fit to the tracer kinetic model yielded arterial CBV of 1.24% ± 0.52% and 0.45 ± 0.11% and perfusion rates of 60.8 ± 32.3 and 34.4 ± 5.4 mL/min/100 g for gray and white matter, respectively. Bolus arrival times were estimated as 75.7 ± 21 ms and 349 ± 78 ms for gray and white matter, respectively. The FMRI experiments showed that VSI pulses yield comparable sensitivity to PCASL with similar timing parameters (TR = 4 s). However, VSI pulses could be used at a faster acquisition speed (TR = 3 s) and were more sensitive to neuronal activity than PCASL pulses, as evidenced by the 31% higher Z scores obtained on average in the active regions. CONCLUSION VSI pulses can be very beneficial for perfusion weighted functional MRI because of their tracer kinetic characteristics, which allow a faster acquisition rate while maintaining an efficient labeling input function.
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Affiliation(s)
| | | | - Douglas C Noll
- University of Michigan FMRI Laboratory, Ann Arbor, Michigan
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45
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Donahue MJ, Achten E, Cogswell PM, De Leeuw FE, Derdeyn CP, Dijkhuizen RM, Fan AP, Ghaznawi R, Heit JJ, Ikram MA, Jezzard P, Jordan LC, Jouvent E, Knutsson L, Leigh R, Liebeskind DS, Lin W, Okell TW, Qureshi AI, Stagg CJ, van Osch MJP, van Zijl PCM, Watchmaker JM, Wintermark M, Wu O, Zaharchuk G, Zhou J, Hendrikse J. Consensus statement on current and emerging methods for the diagnosis and evaluation of cerebrovascular disease. J Cereb Blood Flow Metab 2018; 38:1391-1417. [PMID: 28816594 PMCID: PMC6125970 DOI: 10.1177/0271678x17721830] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/26/2017] [Accepted: 06/10/2017] [Indexed: 01/04/2023]
Abstract
Cerebrovascular disease (CVD) remains a leading cause of death and the leading cause of adult disability in most developed countries. This work summarizes state-of-the-art, and possible future, diagnostic and evaluation approaches in multiple stages of CVD, including (i) visualization of sub-clinical disease processes, (ii) acute stroke theranostics, and (iii) characterization of post-stroke recovery mechanisms. Underlying pathophysiology as it relates to large vessel steno-occlusive disease and the impact of this macrovascular disease on tissue-level viability, hemodynamics (cerebral blood flow, cerebral blood volume, and mean transit time), and metabolism (cerebral metabolic rate of oxygen consumption and pH) are also discussed in the context of emerging neuroimaging protocols with sensitivity to these factors. The overall purpose is to highlight advancements in stroke care and diagnostics and to provide a general overview of emerging research topics that have potential for reducing morbidity in multiple areas of CVD.
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Affiliation(s)
- Manus J Donahue
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Psychiatry, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA
| | - Eric Achten
- Department of Radiology and Nuclear Medicine, Universiteit Gent, Gent, Belgium
| | - Petrice M Cogswell
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Frank-Erik De Leeuw
- Radboud University, Nijmegen Medical Center, Donders Institute Brain Cognition & Behaviour, Center for Neuroscience, Department of Neurology, Nijmegen, The Netherlands
| | - Colin P Derdeyn
- Department of Radiology and Neurology, University of Iowa, Iowa City, IA, USA
| | - Rick M Dijkhuizen
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Audrey P Fan
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Rashid Ghaznawi
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeremy J Heit
- Department of Radiology, Neuroimaging and Neurointervention Division, Stanford University, CA, USA
| | - M Arfan Ikram
- Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands
- Department of Radiology, Erasmus MC, Rotterdam, The Netherlands
| | - Peter Jezzard
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Lori C Jordan
- Department of Pediatrics, Division of Pediatric Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric Jouvent
- Department of Neurology, AP-HP, Lariboisière Hospital, Paris, France
| | - Linda Knutsson
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Richard Leigh
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | | | - Weili Lin
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Thomas W Okell
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Adnan I Qureshi
- Department of Neurology, Zeenat Qureshi Stroke Institute, St. Cloud, MN, USA
| | - Charlotte J Stagg
- Oxford Centre for Human Brain Activity, University of Oxford, Oxford, UK
| | | | - Peter CM van Zijl
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Jennifer M Watchmaker
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Max Wintermark
- Department of Radiology, Neuroimaging and Neurointervention Division, Stanford University, CA, USA
| | - Ona Wu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Greg Zaharchuk
- Department of Radiology, Neuroimaging and Neurointervention Division, Stanford University, CA, USA
| | - Jinyuan Zhou
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
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Jezzard P, Chappell MA, Okell TW. Arterial spin labeling for the measurement of cerebral perfusion and angiography. J Cereb Blood Flow Metab 2018; 38:603-626. [PMID: 29168667 PMCID: PMC5888859 DOI: 10.1177/0271678x17743240] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Arterial spin labeling (ASL) is an MRI technique that was first proposed a quarter of a century ago. It offers the prospect of non-invasive quantitative measurement of cerebral perfusion, making it potentially very useful for research and clinical studies, particularly where multiple longitudinal measurements are required. However, it has suffered from a number of challenges, including a relatively low signal-to-noise ratio, and a confusing number of sequence variants, thus hindering its clinical uptake. Recently, however, there has been a consensus adoption of an accepted acquisition and analysis framework for ASL, and thus a better penetration onto clinical MRI scanners. Here, we review the basic concepts in ASL and describe the current state-of-the-art acquisition and analysis approaches, and the versatility of the method to perform both quantitative cerebral perfusion measurement, along with quantitative cerebral angiographic measurement.
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Affiliation(s)
- Peter Jezzard
- 1 Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - Thomas W Okell
- 1 Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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47
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Shin T, Qin Q. Characterization and suppression of stripe artifact in velocity-selective magnetization-prepared unenhanced MR angiography. Magn Reson Med 2018. [PMID: 29536569 DOI: 10.1002/mrm.27160] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE To characterize and suppress stripe artifact associated with velocity-selective (VS) magnetization for unenhanced MRA. METHODS Extended phase graph formalism was used to show that the stripe artifact contains multiples of the fundamental frequency that is determined by the area of unipolar VS gradient. Four VS preparation pulses whose excitation profiles are spatially shifted by quarter the fundamental period of the stripes, were applied alternately. For further suppression of the artifact, k-space data at kz = 0 were averaged over the 4 VS preparations. The proposed schemes were tested in a chicken breast phantom and healthy human subjects. RESULTS When the standard VS preparation scheme was used, stripe artifact was shown in all the reconstructed images and appeared as artifactual peaks in k-space that corresponded to the first and second order harmonics of the fundamental frequency. Alternate application of the 4 phase-shifted VS preparation pulses suppressed the stripes, but not completely, as evidenced by residual erroneous peaks in k-space. After the k-space averaging, the stripe artifact was nearly eliminated. CONCLUSION Stripe artifact in VS-MRA consists of multiples of the fundamental frequency and can be effectively suppressed through alternate application of phase-shifted VS preparations along with k-space averaging.
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Affiliation(s)
- Taehoon Shin
- Division of Mechanical and Biomedical Engineering, Ewha Womans University, Seoul, South Korea.,Department of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Qin Qin
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland
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48
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Liu D, Xu F, Lin DD, van Zijl PCM, Qin Q. Quantitative measurement of cerebral blood volume using velocity-selective pulse trains. Magn Reson Med 2016; 77:92-101. [PMID: 27797101 DOI: 10.1002/mrm.26515] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 09/26/2016] [Accepted: 09/26/2016] [Indexed: 12/20/2022]
Abstract
PURPOSE To develop a non-contrast-enhanced MRI method for cerebral blood volume (CBV) mapping using velocity-selective (VS) pulse trains. METHODS The new pulse sequence applied velocity-sensitive gradient waveforms in the VS label modules and velocity-compensated ones in the control scans. Sensitivities to the gradient imperfections (e.g., eddy currents) were evaluated through phantom studies. CBV quantification procedures based on simulated labeling efficiencies for arteriolar, capillary, and venular blood as a function of cutoff velocity (Vc) are presented. Experiments were conducted on healthy volunteers at 3T to examine the effects of unbalanced diffusion weighting, cerebrospinal (CSF) contamination and variation of Vc. RESULTS Phantom results of the used VS pulse trains demonstrated robustness to eddy currents. The mean CBV values of gray matter and white matter for the experiments using Vc = 3.5 mm/s and velocity-compensated control with CSF-nulling were 5.1 ± 0.6 mL/100 g and 2.4 ± 0.2 mL/100 g, respectively, which were 23% and 32% lower than results from the experiment with velocity-insensitive control, corresponding to 29% and 25% lower in averaged temporal signal-to-noise ratio values. CONCLUSION A novel technique using VS pulse trains was demonstrated for CBV mapping. The results were both qualitatively and quantitatively close to those from existing methods. Magn Reson Med 77:92-101, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Dexiang Liu
- Department of Radiology, Panyu District Central Hospital, Guangzhou, Guangdong Province, China.,The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Feng Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Doris D Lin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter C M van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Qin Qin
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
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