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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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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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Okell TW, Chiew M. Optimization of 4D combined angiography and perfusion using radial imaging and arterial spin labeling. Magn Reson Med 2023; 89:1853-1870. [PMID: 36533868 PMCID: PMC10952652 DOI: 10.1002/mrm.29558] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 11/27/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022]
Abstract
PURPOSE To extend and optimize a non-contrast MRI technique to obtain whole head 4D (time-resolved 3D) qualitative angiographic and perfusion images from a single scan. METHODS 4D combined angiography and perfusion using radial imaging and arterial spin labeling (CAPRIA) uses pseudocontinuous labeling with a 3D golden ratio ("koosh ball") readout to continuously image the blood water as it travels through the arterial system and exchanges into the tissue. High spatial/temporal resolution angiograms and low spatial/temporal resolution perfusion images can be flexibly reconstructed from the same raw k-space data. Constant and variable flip angle (CFA and VFA, respectively) excitation schedules were optimized through simulations and tested in healthy volunteers. A conventional sensitivity encoding (SENSE) reconstruction was compared against a locally low rank (LLR) reconstruction, which leverages spatiotemporal correlations. Comparison was also made with time-matched time-of-flight angiography and multi-delay EPI perfusion images. Differences in image quality were assessed through split-scan repeatability. RESULTS The optimized VFA schedule (2-9°) resulted in a significant (p < 0.001) improvement in image quality (up to 84% vs. CFA), particularly for the lower SNR perfusion images. The LLR reconstruction provided effective denoising without biasing the signal timecourses, significantly improving angiographic and perfusion image quality and repeatability (up to 143%, p < 0.001). 4D CAPRIA performed well compared with time-of-flight angiography and had better perfusion signal repeatability than the EPI-based approach (p < 0.001). CONCLUSION 4D CAPRIA optimized using a VFA schedule and LLR reconstruction can yield high quality whole head 4D angiograms and perfusion images from a single scan.
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Affiliation(s)
- Thomas W. Okell
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical NeurosciencesUniversity of Oxford
OxfordUK
| | - Mark Chiew
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical NeurosciencesUniversity of Oxford
OxfordUK
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Ackerman JJH. In memoriam: William T. Dixon (1945-2022). Magn Reson Med 2023; 89:1293-1296. [PMID: 36579771 DOI: 10.1002/mrm.29568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 12/30/2022]
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k-space weighted image average (KWIA) for ASL-based dynamic MR angiography and perfusion imaging. Magn Reson Imaging 2021; 86:94-106. [PMID: 34871715 PMCID: PMC8713133 DOI: 10.1016/j.mri.2021.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/17/2021] [Accepted: 11/29/2021] [Indexed: 11/23/2022]
Abstract
A novel denoising algorithm termed k-space weighted image average (KWIA) was proposed to improve the signal-to-noise ratio (SNR) of dynamic MRI, such as arterial spin labeling (ASL)-based dynamic magnetic resonance angiography (dMRA) and perfusion imaging. KWIA divides the k-space of each time frame into multiple rings, the central ring of the k-space remains intact to preserve the image contrast and temporal resolution, while outer rings are progressively averaged with neighboring time frames to increase SNR. Simulations and in-vivo dMRA and multi-delay ASL studies were performed to evaluate the performance of KWIA under various MRI acquisition conditions. SNR ratios and temporal signal errors between KWIA-processed and the original data were measured. Visualization of dynamic blood flow signals as well as quantitative parametric maps were evaluated for KWIA-processed images as compared to the original images. KWIA achieved a SNR ratio of 1.73 for dMRA and 2.0 for multi-delay ASL respectively, which were in accordance with the theoretical predictions. Improved visualization of dynamic blood flow signals was demonstrated using KWIA in distal small vessels in dMRA and small brain structures in multi-delay ASL. Approximately 5% temporal errors were observed in both KWIA-processed dMRA and ASL signals. Fine anatomical features were revealed in the quantitative parametric maps of dMRA, and the residuals of model fitting were reduced for multi-delay ASL. Compared to other conventional denoising methods, KWIA is a flexible denoising algorithm that improves the SNR of ASL-based dMRA and perfusion MRI by up to 2-fold without compromising spatial and temporal resolution or quantification accuracy.
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Optimization of 4D-MR angiography based on superselective pseudo-continuous arterial spin labeling combined with CENTRA-keyhole and view-sharing (4D-S-PACK) for vessel-selective visualization of the internal carotid artery and vertebrobasilar artery systems. Magn Reson Imaging 2021; 85:287-296. [PMID: 34740801 DOI: 10.1016/j.mri.2021.10.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 10/29/2021] [Accepted: 10/30/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE This study investigated the optimal labeling position and gradient moment for 4D-MR angiography based on superselective pseudo-continuous arterial spin labeling combined with CENTRA-keyhole and view-sharing (4D-S-PACK) for vessel-selective flow visualization of the internal carotid artery (ICA) and vertebrobasilar artery (VBA) systems. METHODS Seven healthy volunteers were scanned with a 3.0 T MR scanner. To visualize the ICA system, the labeling focus was placed in the right ICA at 55, 75 and 95 mm below the imaging slab. To visualize the VBA system, the labeling focus was placed in the basilar artery (BA), upper vertebral artery (VA upper), and lower vertebral artery (VA lower). Two sizes of labeling focus were created using gradient moments of 0.5 and 0.75 mT/m ms. The contrast-to-noise ratio (CNR) was measured in the middle cerebral artery (MCA) and posterior cerebral artery (PCA) branches. RESULTS CNRs increased as the distance between the center of the imaging slab and the labeling position decreased in all MCA segments. CNRs obtained with VA lower tended to be higher than those obtained with BA and VA upper in all PCA segments. Selective vessel visualization was achieved with the gradient moment of 0.75 mT/m ms for the ICA and VBA system. CONCLUSION The optimal 4D-S-PACK gradient moment was found to be 0.75 mT/m ms for the ICA and VBA systems. When visualizing the ICA system, the labeling position should be placed as close as possible to the imaging slab. When visualizing the VBA system, the labeling position should be placed at VA lower .
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Noncontrast Magnetic Resonance Angiography in the Era of Nephrogenic Systemic Fibrosis and Gadolinium Deposition. J Comput Assist Tomogr 2021; 45:37-51. [PMID: 32976265 DOI: 10.1097/rct.0000000000001074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
ABSTRACT Gadolinium-based contrast agents for clinical magnetic resonance imaging are overall safe. However, the discovery of nephrogenic systemic fibrosis in patients with severe renal impairment and gadolinium deposition in patients receiving contrast have generated developments in contrast-free imaging of the vasculature, that is, noncontrast magnetic resonance angiography. This article presents an update on noncontrast magnetic resonance angiography techniques, with comparison to other imaging alternatives. Potential benefits and challenges to implementation, and evidence to date for various clinical applications are discussed.
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Edelman RR, Koktzoglou I. Noncontrast MR angiography: An update. J Magn Reson Imaging 2019; 49:355-373. [PMID: 30566270 PMCID: PMC6330154 DOI: 10.1002/jmri.26288] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/24/2018] [Accepted: 07/26/2018] [Indexed: 12/12/2022] Open
Abstract
Both computed tomography (CT) angiography (CTA) and contrast-enhanced MR angiography (CEMRA) have proven to be useful and accurate cross-sectional imaging modalities over a wide range of vascular territories and vascular disorders. A key advantage of MRA is that, unlike CTA, it can be performed without the administration of a contrast agent. In this review article we consider the motivations for using noncontrast MRA, potential contrast mechanisms, imaging techniques, advantages, and drawbacks with respect to CTA and CEMRA, and the level of evidence for using the various MRA techniques. In addition, we explore new developments that promise to expand the reliability and range of clinical applications for noncontrast MRA, along with functional MRA capabilities not available with CTA or CEMRA. Level of Evidence: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:355-373.
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Affiliation(s)
- Robert R. Edelman
- Radiology, Northshore University HealthSystem, Evanston, IL
- Radiology, Northwestern Memorial Hospital, Chicago, IL
| | - Ioannis Koktzoglou
- Radiology, Northshore University HealthSystem, Evanston, IL
- Radiology, University of Chicago Pritzker School of Medicine, Chicago, IL
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Okell TW. Combined angiography and perfusion using radial imaging and arterial spin labeling. Magn Reson Med 2019; 81:182-194. [PMID: 30024066 PMCID: PMC6282709 DOI: 10.1002/mrm.27366] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 03/28/2018] [Accepted: 04/25/2018] [Indexed: 11/24/2022]
Abstract
PURPOSE To demonstrate the feasibility of a novel noninvasive MRI technique for the comprehensive evaluation of blood flow to the brain: combined angiography and perfusion using radial imaging and arterial spin labeling (CAPRIA). METHODS In the CAPRIA pulse sequence, blood labeled with a pseudocontinuous arterial spin labeling pulse train is continuously imaged as it flows through the arterial tree and into the brain tissue using a golden ratio radial readout. From a single raw data set, this flexible imaging approach allows the reconstruction of both high spatial/temporal resolution angiographic images with a high undersampling factor and low spatial/temporal resolution perfusion images with a low undersampling factor. The sparse and high SNR nature of angiographic images ensures that radial undersampling artifacts are relatively benign, even when using a simple regridding image reconstruction. Pulse sequence parameters were optimized through sampling efficiency calculations and the numerical evaluation of modified pseudocontinuous arterial spin labeling signal models. A comparison was made against conventional pseudocontinuous arterial spin labeling angiographic and perfusion acquisitions. RESULTS 2D CAPRIA data in healthy volunteers demonstrated the feasibility of this approach, with good vessel visualization in the angiographic images and clear tissue perfusion signal when reconstructed at 108-ms and 252-ms temporal resolution, respectively. Images were qualitatively similar to those from conventional acquisitions, but CAPRIA had significantly higher SNR efficiency (48% improvement on average, P = 0.02). CONCLUSION The CAPRIA technique shows potential for the efficient evaluation of both macrovascular blood flow and tissue perfusion within a single scan, with potential applications in a range of cerebrovascular diseases.
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Affiliation(s)
- Thomas W. Okell
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUnited Kingdom
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Non contrast, Pseudo-Continuous Arterial Spin Labeling and Accelerated 3-Dimensional Radial Acquisition Intracranial 3-Dimensional Magnetic Resonance Angiography for the Detection and Classification of Intracranial Arteriovenous Shunts. Invest Radiol 2018; 53:80-86. [PMID: 28937545 DOI: 10.1097/rli.0000000000000411] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES The aim of this study was to assess the sensitivity and specificity of pseudo-continuous arterial spin labeling (PCASL) magnetic resonance angiography (MRA) with 3-dimensional (3D) radial acquisition for the detection of intracranial arteriovenous (AV) shunts. MATERIALS AND METHODS A total of 32 patients who underwent PCASL-MRA, clinical magnetic resonance imaging (MRI)/MRA exam, and digital subtraction angiography (DSA) were included in this retrospective analysis. Twelve patients presented with AV shunts. Among these were 8 patients with AV malformations (AVM) and 4 patients with AV fistulas (AVF). The clinical MRI/MRA included 3D time-of-flight MRA in all cases and time-resolved, contrast-enhanced MRA in 9 cases (6 cases with AV shunting). Research MRI and clinical MRI were independently evaluated by 2 neuroradiologists blinded to patient history. A third radiologist evaluated DSA imaging. A diagnostic confidence score was used for the presence of abnormalities associated with AV shunting (1-5). The AVMs were characterized using the Spetzler-Martin scale, whereas AVFs were characterized using the Borden classification. κ Statistics were applied to assess intermodality agreement. RESULTS Compared with clinical MRA, noncontrast PCASL-MRA with 3D radial acquisition yielded excellent sensitivity and specificity for the detection of intracranial AV shunts (reader 1: 100%/100%, clinical MRA: 91.7%, 94.4%; reader 2: 91.7%/100%, clinical MRA: 91.7%/100%). Diagnostic confidence was 4.8/4.66 with PCASL-MRA and 4.25/4.66 with clinical MRA. For AVM characterization with PCASL-MRA, intermodality agreement with DSA showed κ values of 0.43 and 0.6 for readers 1 and 2, respectively. For AVF characterization, intermodality agreement showed κ values of 0.56 for both readers. CONCLUSION Noncontrast PCASL-MRA with 3D radial acquisition is a potential tool for the detection and characterization of intracranial AV shunts with a sensitivity and specificity equivalent or higher than routine clinical MRA.
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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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Yoo RE, Yun TJ, Yoo DH, Cho YD, Kang HS, Yoon BW, Jung KH, Kang KM, Choi SH, Kim JH, Sohn CH. Monitoring cerebral blood flow change through use of arterial spin labelling in acute ischaemic stroke patients after intra-arterial thrombectomy. Eur Radiol 2018; 28:3276-3284. [PMID: 29476217 DOI: 10.1007/s00330-018-5319-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/03/2018] [Accepted: 01/09/2018] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To evaluate the ability of arterial spin labelling perfusion-weighted imaging (ASL-PWI) to identify reperfusion status and to predict the early neurological outcome of acute ischaemic stroke patients after intra-arterial (IA) thrombectomy. METHODS A total of 51 acute ischaemic stroke patients who underwent IA thrombectomy were retrospectively reviewed. Asymmetrical index before and after IA thrombectomy (AICBFpre and AICBFpost) and volume ratio of the reperfused territory to the baseline perfusion abnormality (reperfusion volume ratio) were calculated on ASL-PWI. A paired t-test was used to compare AICBFpre and AICBFpost. Pearson correlation and multiple linear regression were performed to evaluate correlations between the imaging parameters and NIHSS scores. RESULTS Mean AICBFpost was significantly higher than mean AICBFpre (0.923±0.352 vs. 0.312±0.191, p<0.001). AICBFpre had a significant correlation with NIHSSpre (pr=-0.430, p=.004). ∆AICBF had significant correlations with NIHSS24 h, NIHSS5-7 days and ∆NIHSS5-7 days (r=-0.356, p=0.028; r=-0.597, p<0.001; r=-0.346, p=0.033, respectively). ∆AICBF, reperfusion volume ratio and baseline infarct volume were significant independent predictors for NIHSS5-7 days. CONCLUSIONS ASL-PWI has the potential to serve as a non-invasive imaging tool to monitor the reperfusion status and predict the early neurological outcome of acute ischaemic stroke patients after IA thrombectomy. KEY POINTS • CBF change on ASL-PWI after IA thrombectomy correlated with NIHSS scores. • ASL-PWI can non-invasively monitor reperfusion in AIS patients after IA thrombectomy. • ASL-PWI may predict early outcome of AIS patients after IA thrombectomy.
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Affiliation(s)
- Roh-Eul Yoo
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Korea
| | - Tae Jin Yun
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea. .,Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Korea.
| | - Dong Hyun Yoo
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Korea
| | - Young Dae Cho
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Korea
| | - Hyun-Seung Kang
- Department of Neurosurgery, Seoul National University Hospital, Seoul, Republic of Korea
| | - Byung-Woo Yoon
- Department of Neurology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Keun-Hwa Jung
- Department of Neurology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Koung Mi Kang
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Korea
| | - Seung Hong Choi
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Korea
| | - Ji-Hoon Kim
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Korea
| | - Chul-Ho Sohn
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiology, Seoul National University Hospital, 101, Daehangno, Jongno-gu, Seoul, 110-744, Korea
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Edelman RR, Serhal A, Pursnani A, Pang J, Koktzoglou I. Cardiovascular cine imaging and flow evaluation using Fast Interrupted Steady-State (FISS) magnetic resonance. J Cardiovasc Magn Reson 2018; 20:12. [PMID: 29458384 PMCID: PMC5819298 DOI: 10.1186/s12968-018-0433-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 02/01/2018] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Existing cine imaging techniques rely on balanced steady-state free precession (bSSFP) or spoiled gradient-echo readouts, each of which has limitations. For instance, with bSSFP, artifacts occur from rapid through-plane flow and off-resonance effects. We hypothesized that a prototype cine technique, radial fast interrupted steady-state (FISS), could overcome these limitations. The technique was compared with standard cine bSSFP for cardiac function, coronary artery conspicuity, and aortic valve morphology. Given its advantageous properties, we further hypothesized that the cine FISS technique, in combination with arterial spin labeling (ASL), could provide an alternative to phase contrast for visualizing in-plane flow patterns within the aorta and branch vessels. MAIN BODY The study was IRB-approved and subjects provided consent. Breath-hold cine FISS and bSSFP were acquired using similar imaging parameters. There was no significant difference in biplane left ventricular ejection fraction or cardiac image quality between the two techniques. Compared with cine bSSFP, cine FISS demonstrated a marked decrease in fat signal which improved conspicuity of the coronary arteries, while suppression of through-plane flow artifact on thin-slice cine FISS images improved visualization of the aortic valve. Banding artifacts in the subcutaneous tissues were reduced. In healthy subjects, dynamic flow patterns were well visualized in the aorta, coronary and renal arteries using cine FISS ASL, even when the slice was substantially thicker than the vessel diameter. CONCLUSION Cine FISS demonstrates several benefits for cardiovascular imaging compared with cine bSSFP, including better suppression of fat signal and reduced artifacts from through-plane flow and off-resonance effects. The main drawback is a slight (~ 20%) decrease in temporal resolution. In addition, preliminary results suggest that cine FISS ASL provides a potential alternative to phase contrast techniques for in-plane flow quantification, while enabling an efficient, visually-appealing, semi-projective display of blood flow patterns throughout the course of an artery and its branches.
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Affiliation(s)
- Robert R. Edelman
- Radiology, Northshore University HealthSystem, Evanston, IL USA
- Radiology, Northwestern Memorial Hospital, Chicago, IL USA
- Evanston, IL USA
| | - Ali Serhal
- Radiology, Northshore University HealthSystem, Evanston, IL USA
- Radiology, Northwestern Memorial Hospital, Chicago, IL USA
| | - Amit Pursnani
- Medicine, Northshore University HealthSystem, Evanston, IL USA
- Medicine, University of Chicago Pritzker School of Medicine, Chicago, IL USA
| | - Jianing Pang
- Siemens Medical Solutions USA Inc., Chicago, IL USA
| | - Ioannis Koktzoglou
- Radiology, Northshore University HealthSystem, Evanston, IL USA
- Radiology, University of Chicago Pritzker School of Medicine, Chicago, IL USA
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Li X, Auerbach EJ, Van de Moortele PF, Ugurbil K, Metzger GJ. Quantitative single breath-hold renal arterial spin labeling imaging at 7T. Magn Reson Med 2018; 79:815-825. [PMID: 28488274 PMCID: PMC5680158 DOI: 10.1002/mrm.26742] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 12/18/2022]
Abstract
PURPOSE To evaluate the feasibility of quantitative single breath-hold renal arterial spin labeling (ASL) imaging at 7T. METHODS A single-shot fast spin echo FAIR (flow-sensitive alternating inversion recovery) method was used to perform two studies. First, a multi-delay perfusion study was performed to estimate the spin labeling temporal bolus width achievable with a local transceiver array coil at 7T. Second, with a conservatively defined bolus width, a quantitative perfusion study was performed using the single subtraction approach. To address issues of B1+ inhomogeneity/efficiency and excessive short-term specific absorption rates, various strategies were used, such as dynamic radiofrequency shimming and optimization. RESULTS A conservative temporal bolus width of 600 ms determined from the multi-delay study was applied for single-subtraction imaging to measure the renal blood flow in the cortex and medulla: 303 ± 31.8 and 91.3 ± 15.2 (mL/100 g/min), respectively. The estimated spatial and temporal signal-to-noise ratios of renal perfusion measurements were 3.8 ± 0.7 and 2.4 ± 0.6 for the cortex, and 2.2 ± 0.6 and 1.4 ± 0.2 for the medulla. CONCLUSION With proper management of field strength specific challenges, quantitative renal ASL imaging can be achieved at 7T within a single breath-hold. Magn Reson Med 79:815-825, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Xiufeng Li
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, United States
| | - Edward J. Auerbach
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, United States
| | | | - Kamil Ugurbil
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, United States
| | - Gregory J. Metzger
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, United States
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16
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Non-Invasive Renal Perfusion Imaging Using Arterial Spin Labeling MRI: Challenges and Opportunities. Diagnostics (Basel) 2018; 8:diagnostics8010002. [PMID: 29303965 PMCID: PMC5871985 DOI: 10.3390/diagnostics8010002] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 12/25/2017] [Accepted: 01/02/2018] [Indexed: 12/28/2022] Open
Abstract
Tissue perfusion allows for delivery of oxygen and nutrients to tissues, and in the kidneys is also a key determinant of glomerular filtration. Quantification of regional renal perfusion provides a potential window into renal (patho) physiology. However, non-invasive, practical, and robust methods to measure renal perfusion remain elusive, particularly in the clinic. Arterial spin labeling (ASL), a magnetic resonance imaging (MRI) technique, is arguably the only available method with potential to meet all these needs. Recent developments suggest its viability for clinical application. This review addresses several of these developments and discusses remaining challenges with the emphasis on renal imaging in human subjects.
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17
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Rydhög AS, Szczepankiewicz F, Wirestam R, Ahlgren A, Westin CF, Knutsson L, Pasternak O. Separating blood and water: Perfusion and free water elimination from diffusion MRI in the human brain. Neuroimage 2017; 156:423-434. [PMID: 28412443 PMCID: PMC5548601 DOI: 10.1016/j.neuroimage.2017.04.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Revised: 04/07/2017] [Accepted: 04/08/2017] [Indexed: 12/21/2022] Open
Abstract
The assessment of the free water fraction in the brain provides important information about extracellular processes such as atrophy and neuroinflammation in various clinical conditions as well as in normal development and aging. Free water estimates from diffusion MRI are assumed to account for freely diffusing water molecules in the extracellular space, but may be biased by other pools of molecules in rapid random motion, such as the intravoxel incoherent motion (IVIM) of blood, where water molecules perfuse in the randomly oriented capillary network. The goal of this work was to separate the signal contribution of the perfusing blood from that of free-water and of other brain diffusivities. The influence of the vascular compartment on the estimation of the free water fraction and other diffusivities was investigated by simulating perfusion in diffusion MRI data. The perfusion effect in the simulations was significant, especially for the estimation of the free water fraction, and was maintained as long as low b-value data were included in the analysis. Two approaches to reduce the perfusion effect were explored in this study: (i) increasing the minimal b-value used in the fitting, and (ii) using a three-compartment model that explicitly accounts for water molecules in the capillary blood. Estimation of the model parameters while excluding low b-values reduced the perfusion effect but was highly sensitive to noise. The three-compartment model fit was more stable and additionally, provided an estimation of the volume fraction of the capillary blood compartment. The three-compartment model thus disentangles the effects of free water diffusion and perfusion, which is of major clinical importance since changes in these components in the brain may indicate different pathologies, i.e., those originating from the extracellular space, such as neuroinflammation and atrophy, and those related to the vascular space, such as vasodilation, vasoconstriction and capillary density. Diffusion MRI data acquired from a healthy volunteer, using multiple b-shells, demonstrated an expected non-zero contribution from the blood fraction, and indicated that not accounting for the perfusion effect may explain the overestimation of the free water fraction evinced in previous studies. Finally, the applicability of the method was demonstrated with a dataset acquired using a clinically feasible protocol with shorter acquisition time and fewer b-shells.
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Affiliation(s)
- Anna S Rydhög
- Department of Medical Radiation Physics, Lund University, Barngatan 2B, SE-221 85 Lund, Sweden.
| | - Filip Szczepankiewicz
- Department of Medical Radiation Physics, Lund University, Barngatan 2B, SE-221 85 Lund, Sweden.
| | - Ronnie Wirestam
- Department of Medical Radiation Physics, Lund University, Barngatan 2B, SE-221 85 Lund, Sweden.
| | - André Ahlgren
- Department of Medical Radiation Physics, Lund University, Barngatan 2B, SE-221 85 Lund, Sweden.
| | - Carl-Fredrik Westin
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 1249 Boylston St, Boston, MA 02215, USA.
| | - Linda Knutsson
- Department of Medical Radiation Physics, Lund University, Barngatan 2B, SE-221 85 Lund, Sweden; The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, 600 N. Wolf Street, Park 311, Baltimore, MD 21287, USA.
| | - Ofer Pasternak
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 1249 Boylston St, Boston, MA 02215, USA; Department of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, 1249 Boylston St, Boston, MA 02215, USA.
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18
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Improvement in visualization of carotid artery uniformity using silent magnetic resonance angiography. Radiol Phys Technol 2016; 10:113-120. [DOI: 10.1007/s12194-016-0375-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/29/2016] [Accepted: 08/30/2016] [Indexed: 11/25/2022]
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19
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Okell TW, Schmitt P, Bi X, Chappell MA, Tijssen RHN, Sheerin F, Miller KL, Jezzard P. Optimization of 4D vessel-selective arterial spin labeling angiography using balanced steady-state free precession and vessel-encoding. NMR IN BIOMEDICINE 2016; 29:776-786. [PMID: 27074149 PMCID: PMC4879350 DOI: 10.1002/nbm.3515] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 01/14/2016] [Accepted: 02/19/2016] [Indexed: 06/05/2023]
Abstract
Vessel-selective dynamic angiograms provide a wealth of useful information about the anatomical and functional status of arteries, including information about collateral flow and blood supply to lesions. Conventional x-ray techniques are invasive and carry some risks to the patient, so non-invasive alternatives are desirable. Previously, non-contrast dynamic MRI angiograms based on arterial spin labeling (ASL) have been demonstrated using both spoiled gradient echo (SPGR) and balanced steady-state free precession (bSSFP) readout modules, but no direct comparison has been made, and bSSFP optimization over a long readout period has not been fully explored. In this study bSSFP and SPGR are theoretically and experimentally compared for dynamic ASL angiography. Unlike SPGR, bSSFP was found to have a very low ASL signal attenuation rate, even when a relatively large flip angle and short repetition time were used, leading to a threefold improvement in the measured signal-to-noise ratio (SNR) efficiency compared with SPGR. For vessel-selective applications, SNR efficiency can be further improved over single-artery labeling methods by using a vessel-encoded pseudo-continuous ASL (VEPCASL) approach. The combination of a VEPCASL preparation with a time-resolved bSSFP readout allowed the generation of four-dimensional (4D; time-resolved three-dimensional, 3D) vessel-selective cerebral angiograms in healthy volunteers with 59 ms temporal resolution. Good quality 4D angiograms were obtained in all subjects, providing comparable structural information to 3D time-of-flight images, as well as dynamic information and vessel selectivity, which was shown to be high. A rapid 1.5 min dynamic two-dimensional version of the sequence yielded similar image features and would be suitable for a busy clinical protocol. Preliminary experiments with bSSFP that included the extracranial vessels showed signal loss in regions of poor magnetic field homogeneity. However, for intracranial vessel-selective angiography, the proposed bSSFP VEPCASL sequence is highly SNR efficient and could provide useful information in a range of cerebrovascular diseases. © 2016 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.
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Affiliation(s)
- Thomas W. Okell
- FMRIB CentreNuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Peter Schmitt
- MR Application and Workflow DevelopmentSiemens AG, Healthcare SectorErlangenGermany
| | | | - Michael A. Chappell
- FMRIB CentreNuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
- Institute of Biomedical EngineeringUniversity of OxfordOxfordUK
| | - Rob H. N. Tijssen
- FMRIB CentreNuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
- Department of RadiotherapyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Fintan Sheerin
- NeuroradiologyOxford University Hospitals NHS TrustOxfordUK
| | - Karla L. Miller
- FMRIB CentreNuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Peter Jezzard
- FMRIB CentreNuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
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Stafford RB, Woo MK, Oh SH, Dolui S, Zhao T, Kim YB, Detre JA, Cho ZH, Lee J. An Actively Decoupled Dual Transceiver Coil System for Continuous ASL at 7 T. INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY 2016; 26:106-115. [PMID: 27695192 PMCID: PMC5042328 DOI: 10.1002/ima.22165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
7 T arterial spin labeling (ASL) faces major challenges including the increased specific absorption rate (SAR) and increased B0 and B1 inhomogeneity. This work describes the design and implementation of a dual-coil system that allows for continuous ASL (CASL) at 7 T. This system consisted of an actively detunable eight-channel transceiver head coil, and a three-channel transceiver labeling coil. Four experiments were performed in 5 healthy subjects: (i) to demonstrate that active detuning during ASL labeling reduces magnetization transfer; (ii) to measure the B1 profile at the labeling plane; (iii) to quantify B0 off-resonance at the labeling plane; and (iv) to collect in vivo CASL data. The magnetization transfer ratio in the head coil was reduced to 0.0 ± 0.2% by active detuning during labeling. The measured B1 profiles in all 5 subjects were sufficient to satisfy the flow-driven adiabatic inversion necessary for CASL, however the actual labeling efficiency was significantly impacted by B0 off-resonance at the labeling plane. The measured CASL percent signal change in gray matter (0.94% ± 0.10%) corresponds with the low labeling efficiency predicted by the B0 off-resonance. This work demonstrates progress in the technical implementation of 7 T CASL, and reinforces the need for improved B0 homogeneity at the labeling plane.
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Affiliation(s)
- Randall B Stafford
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada
| | - Myung-Kyun Woo
- Neuroscience Research Institute, Gachon University, Incheon, Korea; Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea; Department of Electrical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Se-Hong Oh
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; Imaging Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Sudipto Dolui
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Tiejun Zhao
- Siemens Medical Solutions USA, Inc., Siemens Healthcare, New York, NY, USA
| | - Young-Bo Kim
- Neuroscience Research Institute, Gachon University, Incheon, Korea
| | - John A Detre
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Zang-Hee Cho
- Neuroscience Research Institute, Gachon University, Incheon, Korea; Advanced Institutes of Convergence Technology, Seoul National University, Seoul, Korea
| | - Jongho Lee
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea
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21
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Shrestha M, Mildner T, Schlumm T, Robertson SH, Möller H. Three-dimensional echo-planar cine imaging of cerebral blood supply using arterial spin labeling. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2016; 29:799-810. [PMID: 27225871 PMCID: PMC5124058 DOI: 10.1007/s10334-016-0565-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 04/23/2016] [Accepted: 05/04/2016] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Echo-planar imaging (EPI) with CYlindrical Center-out spatiaL Encoding (EPICYCLE) is introduced as a novel hybrid three-dimensional (3D) EPI technique. Its suitability for the tracking of a short bolus created by pseudo-continuous arterial spin labeling (pCASL) through the cerebral vasculature is demonstrated. MATERIALS AND METHODS EPICYCLE acquires two-dimensional planes of k-space along center-out trajectories. These "spokes" are rotated from shot to shot about a common axis to encode a k-space cylinder. To track a bolus of labeled blood, the same subset of evenly distributed spokes is acquired in a cine fashion after a short period of pCASL. This process is repeated for all subsets to fill the whole 3D k-space of each time frame. RESULTS The passage of short pCASL boluses through the vasculature of a 3D imaging slab was successfully imaged using EPICYCLE. By choosing suitable sequence parameters, the impact of slab excitation on the bolus shape could be minimized. Parametric maps of signal amplitude, transit time, and bolus width reflected typical features of blood transport in large vessels. CONCLUSION The EPICYCLE technique was successfully applied to track a short bolus of labeled arterial blood during its passage through the cerebral vasculature.
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Affiliation(s)
- Manoj Shrestha
- Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstraße 1a, 04103, Leipzig, Germany
| | - Toralf Mildner
- Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstraße 1a, 04103, Leipzig, Germany.
| | - Torsten Schlumm
- Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstraße 1a, 04103, Leipzig, Germany
| | | | - Harald Möller
- Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstraße 1a, 04103, Leipzig, Germany
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22
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Hu LB, Hong N, Zhu WZ. Quantitative Measurement of Cerebral Perfusion with Intravoxel Incoherent Motion in Acute Ischemia Stroke: Initial Clinical Experience. Chin Med J (Engl) 2016; 128:2565-9. [PMID: 26415791 PMCID: PMC4736872 DOI: 10.4103/0366-6999.166033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Background: Intravoxel incoherent motion (IVIM) has the potential to provide both diffusion and perfusion information without an exogenous contrast agent, its application for the brain is promising, however, feasibility studies on this are relatively scarce. The aim of this study is to assess the feasibility of IVIM perfusion in patients with acute ischemic stroke (AIS). Methods: Patients with suspected AIS were examined by magnetic resonance imaging within 24 h of symptom onset. Fifteen patients (mean age was 68.7 ± 8.0 years) who underwent arterial spin labeling (ASL) and diffusion-weighted imaging (DWI) were identified as having AIS with ischemic penumbra were enrolled, where ischemic penumbra referred to the mismatch areas of ASL and DWI. Eleven different b-values were applied in the biexponential model. Regions of interest were selected in ischemic penumbras and contralateral normal brain regions. Fast apparent diffusion coefficients (ADCs) and ASL cerebral blood flow (CBF) were measured. The paired t-test was applied to compare ASL CBF, fast ADC, and slow ADC measurements between ischemic penumbras and contralateral normal brain regions. Linear regression and Pearson's correlation were used to evaluate the correlations among quantitative results. Results: The fast ADCs and ASL CBFs of ischemic penumbras were significantly lower than those of the contralateral normal brain regions (1.93 ± 0.78 μm2/ms vs. 3.97 ± 2.49 μm2/ms, P = 0.007; 13.5 ± 4.5 ml·100 g-1·min-1 vs. 29.1 ± 12.7 ml·100 g-1·min-1, P < 0.001, respectively). No significant difference was observed in slow ADCs between ischemic penumbras and contralateral normal brain regions (0.203 ± 0.090 μm2/ms vs. 0.198 ± 0.100 αμm2/ms, P = 0.451). Compared with contralateral normal brain regions, both CBFs and fast ADCs decreased in ischemic penumbras while slow ADCs remained the same. A significant correlation was detected between fast ADCs and ASL CBFs (r = 0.416, P < 0.05). No statistically significant correlation was observed between ASL CBFs and slow ADCs, or between fast ADCs and slow ADCs (r = 0.111, P = 0.558; r = 0.200, P = 0.289, respectively). Conclusions: The decrease in cerebral blood perfusion primarily results in the decrease in fast ADC in ischemic penumbras; therefore, fast ADC can reflect the perfusion situation in cerebral tissues.
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Affiliation(s)
| | - Nan Hong
- Department of Radiology, Peking University People's Hospital, Beijing 100044, China
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23
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Yoo RE, Yun TJ, Cho YD, Rhim JH, Kang KM, Choi SH, Kim JH, Kim JE, Kang HS, Sohn CH, Park SW, Han MH. Utility of arterial spin labeling perfusion magnetic resonance imaging in prediction of angiographic vascularity of meningiomas. J Neurosurg 2016; 125:536-43. [PMID: 26824378 DOI: 10.3171/2015.8.jns151211] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE Arterial spin labeling perfusion-weighted imaging (ASL-PWI) enables quantification of tissue perfusion without contrast media administration. The aim of this study was to explore whether cerebral blood flow (CBF) from ASL-PWI can reliably predict angiographic vascularity of meningiomas. METHODS Twenty-seven patients with intracranial meningiomas, who had undergone preoperative ASL-PWI and digital subtraction angiography prior to resection, were included. Angiographic vascularity was assessed using a 4-point grading scale and meningiomas were classified into 2 groups: low vascularity (Grades 0 and 1; n = 11) and high vascularity (Grades 2 and 3; n = 16). Absolute CBF, measured at the largest section of the tumor, was normalized to the contralateral gray matter. Correlation between the mean normalized CBF (nCBF) and angiographic vascularity was determined and the mean nCBF values of the 2 groups were compared. Diagnostic performance of the nCBF for differentiating between the 2 groups was assessed. RESULTS The nCBF had a significant positive correlation with angiographic vascularity (ρ = 0.718; p < 0.001). The high-vascularity group had a significantly higher nCBF than the low-vascularity group (3.334 ± 2.768 and 0.909 ± 0.468, respectively; p = 0.003). At the optimal nCBF cutoff value of 1.733, sensitivity and specificity for the differential diagnosis of the 2 groups were 69% (95% CI 41%-89%) and 100% (95% CI 72%-100%), respectively. The area under the receiver operating characteristic curve was 0.875 (p < 0.001). CONCLUSIONS ASL-PWI may provide a reliable and noninvasive means of predicting angiographic vascularity of meningiomas. It may thus assist in selecting potential candidates for preoperative digital subtraction angiography and embolization in clinical practice.
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Affiliation(s)
- Roh-Eul Yoo
- Departments of 1 Radiology and.,Department of Radiology, Seoul National University College of Medicine
| | - Tae Jin Yun
- Departments of 1 Radiology and.,Department of Radiology, Seoul National University College of Medicine
| | - Young Dae Cho
- Departments of 1 Radiology and.,Department of Radiology, Seoul National University College of Medicine
| | | | - Koung Mi Kang
- Departments of 1 Radiology and.,Department of Radiology, Seoul National University College of Medicine
| | - Seung Hong Choi
- Departments of 1 Radiology and.,Department of Radiology, Seoul National University College of Medicine;,Institute of Radiation Medicine, Seoul National University Medical Research Center; and
| | - Ji-Hoon Kim
- Departments of 1 Radiology and.,Department of Radiology, Seoul National University College of Medicine
| | | | | | - Chul-Ho Sohn
- Departments of 1 Radiology and.,Department of Radiology, Seoul National University College of Medicine;,Institute of Radiation Medicine, Seoul National University Medical Research Center; and
| | - Sun-Won Park
- Department of Radiology, Seoul National University College of Medicine;,Department of Radiology, Boramae Medical Center, Seoul, Korea
| | - Moon Hee Han
- Departments of 1 Radiology and.,Department of Radiology, Seoul National University College of Medicine;,Institute of Radiation Medicine, Seoul National University Medical Research Center; and
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Yan L, Salamon N, Wang DJJ. Time-resolved noncontrast enhanced 4-D dynamic magnetic resonance angiography using multibolus TrueFISP-based spin tagging with alternating radiofrequency (TrueSTAR). Magn Reson Med 2016; 71:551-60. [PMID: 23440649 DOI: 10.1002/mrm.24689] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE The goal of this study was to introduce a new noncontrast enhanced 4D dynamic MR angiography (dMRA) technique termed multibolus TrueFISP-based spin tagging with alternating radiofrequency (TrueSTAR). METHODS Multibolus TrueFISP-based spin tagging with alternating radiofrequency was developed by taking advantage of the phenomenon that the steady-state signal of TrueFISP is minimally disturbed by periodically inserted magnetization preparations (e.g., spin tagging) that are sandwiched by two α/2 RF pulses. Both theoretical analysis and experimental studies were carried out to optimize the proposed method which was compared with both pulsed and pseudo-continuous arterial spin labeling-based dMRA in healthy volunteers. Optimized multibolus dMRA was also applied in a patient with arteriovenous malformation to demonstrate its potential clinical utility. RESULTS Multibolus dMRA offered a prolonged tagging bolus compared to the standard single-bolus dMRA, and allowed improved visualization of the draining veins in the arteriovenous malformation patient. Compared to pseudo-continuous arterial spin labeling-based dMRA, multibolus dMRA provided visualization of the full passage of the labeled blood with the flexibility for both static and dynamic magnetic resonance angiography. CONCLUSION By combining the benefits of pulsed and pseudo-continuous arterial spin labeling-based dMRA, multibolus TrueFISP-based spin tagging with alternating radiofrequency can prolong and enhance the tagging bolus without sacrificing imaging speed or temporal resolution.
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Affiliation(s)
- Lirong Yan
- Department of Neurology, Laboratory of Functional MRI Technology, University of California Los Angeles, Los Angeles, California, USA
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25
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Kiruluta AJ, González RG. Magnetic resonance angiography. HANDBOOK OF CLINICAL NEUROLOGY 2016; 135:137-149. [PMID: 27432663 DOI: 10.1016/b978-0-444-53485-9.00007-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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26
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Jensen-Kondering U, Lindner T, van Osch MJ, Rohr A, Jansen O, Helle M. Superselective pseudo-continuous arterial spin labeling angiography. Eur J Radiol 2015; 84:1758-67. [DOI: 10.1016/j.ejrad.2015.05.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 05/22/2015] [Accepted: 05/30/2015] [Indexed: 10/23/2022]
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Lindner T, Jensen-Kondering U, van Osch MJ, Jansen O, Helle M. 3D time-resolved vessel-selective angiography based on pseudo-continuous arterial spin labeling. Magn Reson Imaging 2015; 33:840-6. [PMID: 25777269 DOI: 10.1016/j.mri.2015.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 03/07/2015] [Indexed: 10/23/2022]
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28
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Koktzoglou I, Giri S, Piccini D, Grodzki DM, Flanagan O, Murphy IG, Gupta N, Collins JD, Edelman RR. Arterial spin labeled carotid MR angiography: A phantom study examining the impact of technical and hemodynamic factors. Magn Reson Med 2015; 75:295-301. [PMID: 25684192 DOI: 10.1002/mrm.25611] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 12/17/2014] [Accepted: 12/18/2014] [Indexed: 11/07/2022]
Abstract
PURPOSE To quantify the accuracy of three-dimensional (3D) radial arterial spin labeled (ASL) magnetic resonance angiography (MRA) using vascular models of carotid stenosis. METHODS Eight vascular models were imaged at 1.5 Tesla using pulsatile flow waveforms at rates found in the internal carotid arteries (100-400 mL/min). The impacts of the 3D ASL imaging readout (fast low angle shot (FLASH) versus balanced steady-state free precession (bSSFP)), ultrashort echo time imaging using a pointwise encoding time reduction with radial acquisition (PETRA), and model stenosis severity on the accuracy of vascular model display at the location of stenosis were quantified. Accuracy was computed vis-à-vis a reference bSSFP volume acquired under no flow. Comparisons were made with standard-of-care contrast-enhanced MRA (CEMRA) and Cartesian time-of-flight (TOF) MRA protocols. RESULTS For 50% and 70% stenoses, CEMRA was most accurate (respective accuracies of 81.7% and 78.6%), followed by ASL FLASH (75.7% and 71.8%), ASL PETRA (69.6% and 70.6%), 3D TOF (66.6% and 57.1%), ASL bSSFP (68.7% and 51.2%), and 2D TOF (65.1% and 50.6%). CONCLUSION Flow phantom imaging studies show that ASL MRA can improve the display of hemodynamically significant carotid arterial stenosis compared with TOF MRA, with FLASH and ultrashort echo time readouts being most accurate.
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Affiliation(s)
- Ioannis Koktzoglou
- Department of Radiology, NorthShore University HealthSystem, Evanston, Illinois, USA.,The University of Chicago Pritzker School of Medicine, Chicago, Illinois, USA
| | | | - Davide Piccini
- Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland.,Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | | | - Oisin Flanagan
- Department of Radiology, NorthShore University HealthSystem, Evanston, Illinois, USA.,Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Ian G Murphy
- Department of Radiology, NorthShore University HealthSystem, Evanston, Illinois, USA.,Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - NavYash Gupta
- The University of Chicago Pritzker School of Medicine, Chicago, Illinois, USA.,Department of Surgery, Division of Vascular Surgery, NorthShore University HealthSystem, Evanston, Illinois, USA
| | - Jeremy D Collins
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Robert R Edelman
- Department of Radiology, NorthShore University HealthSystem, Evanston, Illinois, USA.,Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Rahman MM, Kerskens CM, Chattarji S, O'Mara SM. Chronic immobilization stress occludes in vivo cortical activation in an animal model of panic induced by carbon dioxide inhalation. Front Behav Neurosci 2014; 8:311. [PMID: 25278852 PMCID: PMC4165356 DOI: 10.3389/fnbeh.2014.00311] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 08/25/2014] [Indexed: 11/13/2022] Open
Abstract
Breathing high concentrations of carbon dioxide (CO2) can trigger panic and anxiety in humans. CO2 inhalation has been hypothesized to activate neural systems similar to those underlying fear learning, especially those involving the amygdala. Amygdala activity is also upregulated by stress. Recently, however, a separate pathway has been proposed for interoceptive panic and anxiety signals, as patients exhibited CO2-inhalation induced panic responses despite bilateral lesions of the amygdala. This paradoxical observation has raised the possibility that cortical circuits may underlie these responses. We sought to examine these divergent models by comparing in vivo brain activation in unstressed and chronically-stressed rats breathing CO2. Regional cerebral blood flow measurements using functional Magnetic Resonance Imaging (fMRI) in lightly-anaesthetized rats showed especially strong activation of the somatosensory cortex by CO2 inhalation in the unstressed group. Strikingly, prior exposure to chronic stress occluded this effect on cortical activity. This lends support to recent clinical observations and highlights the importance of looking beyond the traditional focus on limbic structures, such as the hippocampus and amygdala, to investigate a role for cortical areas in panic and anxiety in humans.
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Affiliation(s)
| | - Christian M Kerskens
- Trinity College Institute of Neuroscience, Trinity College Dublin Dublin, Ireland
| | - Sumantra Chattarji
- National Center for Biological Sciences, Tata Institute of Fundamental Research Bangalore, India
| | - Shane M O'Mara
- Trinity College Institute of Neuroscience, Trinity College Dublin Dublin, Ireland
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Jahng GH, Li KL, Ostergaard L, Calamante F. Perfusion magnetic resonance imaging: a comprehensive update on principles and techniques. Korean J Radiol 2014; 15:554-77. [PMID: 25246817 PMCID: PMC4170157 DOI: 10.3348/kjr.2014.15.5.554] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/05/2014] [Indexed: 12/16/2022] Open
Abstract
Perfusion is a fundamental biological function that refers to the delivery of oxygen and nutrients to tissue by means of blood flow. Perfusion MRI is sensitive to microvasculature and has been applied in a wide variety of clinical applications, including the classification of tumors, identification of stroke regions, and characterization of other diseases. Perfusion MRI techniques are classified with or without using an exogenous contrast agent. Bolus methods, with injections of a contrast agent, provide better sensitivity with higher spatial resolution, and are therefore more widely used in clinical applications. However, arterial spin-labeling methods provide a unique opportunity to measure cerebral blood flow without requiring an exogenous contrast agent and have better accuracy for quantification. Importantly, MRI-based perfusion measurements are minimally invasive overall, and do not use any radiation and radioisotopes. In this review, we describe the principles and techniques of perfusion MRI. This review summarizes comprehensive updated knowledge on the physical principles and techniques of perfusion MRI.
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Affiliation(s)
- Geon-Ho Jahng
- Department of Radiology, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul 134-727, Korea
| | - Ka-Loh Li
- Wolfson Molecular Imaging Center, The University of Manchester, Manchester M20 3LJ, UK
| | - Leif Ostergaard
- Center for Functionally Integrative Neuroscience, Department of Neuroradiology, Aarhus University Hospital, Aarhus C 8000, Denmark
| | - Fernando Calamante
- Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria 3084, Australia
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31
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Mildner T, Müller K, Hetzer S, Trampel R, Driesel W, Möller HE. Mapping of arterial transit time by intravascular signal selection. NMR IN BIOMEDICINE 2014; 27:594-609. [PMID: 24610794 DOI: 10.1002/nbm.3098] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 02/03/2014] [Accepted: 02/03/2014] [Indexed: 06/03/2023]
Abstract
The arterial transit time (δa ) is a potentially important physiological parameter which may provide valuable information for the characterization of cerebrovascular diseases. The present study shows that δa can be measured by arterial spin labeling (ASL) applied quasi-continuously in an amplitude-modulated fashion at the human neck. Imaging was performed using short repetition times and excitation flip angles of 90°, which resulted in the selection of an ASL signal of mostly intravascular origin. Model-independent estimates of δa were obtained directly from the temporal shift of the ASL time series. An extended two-compartment perfusion model was developed in order to simulate the basic features of the proposed method and to validate the evaluation procedure. Vascular structures found in human δa maps, such as the circle of Willis or cerebral border zones, hint at the sensitivity of the method to most sizes of arterial vessels. Group-averaged values of δa measured from the carotid bifurcation to the tissue of interest in selected regions of the human brain ranged from 925 ms in the insular cortex to 2000 ms in the thalamic region.
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Affiliation(s)
- Toralf Mildner
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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32
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Koktzoglou I, Meyer JR, Ankenbrandt WJ, Giri S, Piccini D, Zenge MO, Flanagan O, Desai T, Gupta N, Edelman RR. Nonenhanced arterial spin labeled carotid MR angiography using three-dimensional radial balanced steady-state free precession imaging. J Magn Reson Imaging 2014; 41:1150-6. [PMID: 24737420 DOI: 10.1002/jmri.24640] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 03/26/2014] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To optimize and preliminarily evaluate a three-dimensional (3D) radial balanced steady-state free precession (bSSFP) arterial spin labeled (ASL) sequence for nonenhanced MR angiography (MRA) of the extracranial carotid arteries. MATERIALS AND METHODS The carotid arteries of 13 healthy subjects and 2 patients were imaged on a 1.5 Tesla MRI system using an undersampled 3D radial bSSFP sequence providing a scan time of ∼4 min and 1 mm(3) isotropic resolution. A hybridized scheme that combined pseudocontinuous and pulsed ASL was used to maximize arterial coverage. The impact of a post label delay period, the sequence repetition time, and radiofrequency (RF) energy configuration of pseudocontinuous labeling on the display of the carotid arteries was assessed with contrast-to-noise ratio (CNR) measurements. Faster, higher undersampled 2 and 1 min scans were tested. RESULTS Using hybridized ASL MRA and a 3D radial bSSFP trajectory, arterial CNR was maximized with a post label delay of 0.2 s, repetition times ≥ 2.5 s (P < 0.05), and by eliminating RF energy during the pseudocontinuous control phase (P < 0.001). With higher levels of undersampling, the carotid arteries were displayed in ≤ 2 min. CONCLUSION Nonenhanced MRA using hybridized ASL with a 3D radial bSSFP trajectory can display long lengths of the carotid arteries with 1 mm(3) isotropic resolution.
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Affiliation(s)
- Ioannis Koktzoglou
- Department of Radiology, NorthShore University HealthSystem, Evanston, Illinois, USA; The University of Chicago Pritzker School of Medicine, Chicago, Illinois, USA
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33
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Perfusion Imaging. J Magn Reson Imaging 2013; 40:269-79. [DOI: 10.1002/jmri.24382] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 08/09/2013] [Indexed: 11/07/2022] Open
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Kopeinigg D, Bammer R. Time-resolved angiography using inflow subtraction (TRAILS). Magn Reson Med 2013; 72:669-78. [PMID: 24166577 DOI: 10.1002/mrm.24985] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 08/21/2013] [Accepted: 09/06/2013] [Indexed: 12/30/2022]
Abstract
PURPOSE A novel pseudo-continuous arterial spin labeling based angiographic method called Time-Resolved Angiography using InfLow Subtraction is introduced and used to acquire time-resolved whole-head angiographic data sets in healthy volunteers in a clinical feasible scan time of less than 5 min. METHODS Using this new method, in conjunction with a sliding window reconstruction, a temporal resolution of 7.2 ms with a low temporal footprint of 432 ms can be achieved. RESULTS Excellent vessel delineation compared to a time-of-flight MRA was demonstrated. Normal variations of the vascular system including the Circle of Willis (CoW) were identified using Time-Resolved Angiography Using Inflow Subtraction. Signal intensities were measured in various vascular segments to quantify the blood transit time. CONCLUSION In this feasibility study, we showed that Time-Resolved Angiography using InfLow Subtraction can be used to acquire hemodynamic information of the whole head in healthy volunteers with a high temporal and spatial resolution. Further studies in patients that suffer from vascular diseases to explore various flow patterns including longer transit time are needed.
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Affiliation(s)
- Daniel Kopeinigg
- Department of Radiology, Stanford University, Stanford, California, USA
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36
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Johnston ME, Zheng Z, Maldjian JA, Whitlow CT, Morykwas MJ, Jung Y. Cerebral blood flow quantification in swine using pseudo-continuous arterial spin labeling. J Magn Reson Imaging 2013; 38:1111-8. [PMID: 24105693 DOI: 10.1002/jmri.24066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 01/10/2013] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To develop quantitative cerebral blood flow (CBF) imaging using pseudo-continuous arterial spin labeling (PCASL) in swine, accounting for their cerebrovascular anatomy and physiology. MATERIALS AND METHODS Five domestic pigs (2.5-3 months, 25 kg) were used in these studies. The orientation of the labeled arteries, T1bl , M0bl , and T1gm were measured in swine. Labeling parameters were tuned with respect to blood velocity to optimize labeling efficiency based on the data collected from three subjects. Finally, CBF and arterial transit time (ATT) maps for two subjects were created from PCASL data to determine global averages. RESULTS The average labeling efficiency over measured velocities of 5-18 cm/s was 0.930. The average T1bl was 1546 ms, the average T1gm was 1224 ms, and the average blood-to-white matter ratio of M0 was 1.25, which was used to find M0bl . The global averages over the subjects were 54.05 mL/100 g tissue/min CBF and 1261 ms ATT. CONCLUSION This study demonstrates the feasibility of PCASL for CBF quantification in swine. Quantification of CBF using PCASL in swine can be further developed as an accessible and cost-effective model of human cerebral perfusion for investigating injuries that affect blood flow.
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Affiliation(s)
- Megan E Johnston
- Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
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37
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Superselective arterial spin labeling applied for flow territory mapping in various cerebrovascular diseases. J Magn Reson Imaging 2013; 38:496-503. [DOI: 10.1002/jmri.24041] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 12/13/2012] [Indexed: 11/07/2022] Open
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Nakamura M, Yoneyama M, Tabuchi T, Takemura A, Obara M, Tatsuno S, Sawano S. Vessel-selective, non-contrast enhanced, time-resolved MR angiography with vessel-selective arterial spin labeling technique (CINEMA–SELECT) in intracranial arteries. Radiol Phys Technol 2013; 6:327-34. [PMID: 23475783 DOI: 10.1007/s12194-013-0204-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 02/12/2013] [Accepted: 02/15/2013] [Indexed: 10/27/2022]
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Yoo RE, Choi SH, Cho HR, Kim TM, Lee SH, Park CK, Park SH, Kim IH, Yun TJ, Kim JH, Sohn CH, Han MH, Chang KH. Tumor blood flow from arterial spin labeling perfusion MRI: A key parameter in distinguishing high-grade gliomas from primary cerebral lymphomas, and in predicting genetic biomarkers in high-grade gliomas. J Magn Reson Imaging 2013; 38:852-60. [DOI: 10.1002/jmri.24026] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 12/07/2012] [Indexed: 12/31/2022] Open
Affiliation(s)
- Roh-Eul Yoo
- Department of Radiology; Seoul National University College of Medicine; Seoul Korea
| | - Seung Hong Choi
- Department of Radiology; Seoul National University College of Medicine; Seoul Korea
| | - Hye Rim Cho
- Department of Radiology; Seoul National University College of Medicine; Seoul Korea
- Department of Radiation Applied Life Science; Seoul National University College of Medicine; Seoul Korea
| | - Tae Min Kim
- Department of Internal Medicine; Cancer Research Institute; Seoul National University College of Medicine; Seoul Korea
| | - Se-Hoon Lee
- Department of Internal Medicine; Cancer Research Institute; Seoul National University College of Medicine; Seoul Korea
| | - Chul-Kee Park
- Department of Neurosurgery; Biomedical Research Institute; Seoul National University College of Medicine; Seoul Korea
| | - Sung-Hye Park
- Department of Pathology; Seoul National University College of Medicine; Seoul Korea
| | - Il Han Kim
- Department of Radiation Oncology; Cancer Research Institute; Seoul National University College of Medicine; Seoul Korea
| | - Tae Jin Yun
- Department of Radiology; Seoul National University College of Medicine; Seoul Korea
| | - Ji-Hoon Kim
- Department of Radiology; Seoul National University College of Medicine; Seoul Korea
| | - Chul-Ho Sohn
- Department of Radiology; Seoul National University College of Medicine; Seoul Korea
| | - Moon Hee Han
- Department of Radiology; Seoul National University College of Medicine; Seoul Korea
| | - Kee Hyun Chang
- Department of Radiology; Seoul National University College of Medicine; Seoul Korea
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Federau C, Maeder P, O’Brien K, Browaeys P, Meuli R, Hagmann P. Quantitative Measurement of Brain Perfusion with Intravoxel Incoherent Motion MR Imaging. Radiology 2012; 265:874-81. [DOI: 10.1148/radiol.12120584] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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41
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Arterial spin labeling: its time is now. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2012; 25:75-7. [PMID: 22427138 DOI: 10.1007/s10334-012-0309-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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42
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Kelly-Cobbs AI, Prakash R, Coucha M, Knight RA, Li W, Ogbi SN, Johnson M, Ergul A. Cerebral myogenic reactivity and blood flow in type 2 diabetic rats: role of peroxynitrite in hypoxia-mediated loss of myogenic tone. J Pharmacol Exp Ther 2012; 342:407-15. [PMID: 22570365 DOI: 10.1124/jpet.111.191296] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Dysregulation of cerebral vascular function and, ultimately, cerebral blood flow (CBF) may contribute to complications such as stroke and cognitive decline in diabetes. We hypothesized that 1) diabetes-mediated neurovascular and myogenic dysfunction impairs CBF and 2) under hypoxic conditions, cerebral vessels from diabetic rats lose myogenic properties because of peroxynitrite (ONOO(-))-mediated nitration of vascular smooth muscle (VSM) actin. Functional hyperemia, the ability of blood vessels to dilate upon neuronal stimulation, and myogenic tone of isolated middle cerebral arteries (MCAs) were assessed as indices of neurovascular and myogenic function, respectively, in 10- to 12-week control and type 2 diabetic Goto-Kakizaki rats. In addition, myogenic behavior of MCAs, nitrotyrosine (NY) levels, and VSM actin content were measured under normoxic and hypoxic [oxygen glucose deprivation (OGD)] conditions with and without the ONOO(-) decomposition catalyst 5,10,15,20-tetrakis(4-sulfonatophenyl) prophyrinato iron (III), chloride (FeTPPs). The percentage of myogenic tone was higher in diabetes, and forced dilation occurred at higher pressures. Functional hyperemia was impaired. Consistent with these findings, baseline CBF was lower in diabetes. OGD reduced the percentage of myogenic tone in both groups, and FeTPPs restored it only in diabetes. OGD increased VSM NY in both groups, and although FeTPPs restored basal levels, it did not correct the reduced filamentous/globular (F/G) actin ratio. Acute alterations in VSM ONOO(-) levels may contribute to hypoxic myogenic dysfunction, but this cannot be solely explained by the decreased F/G actin ratio due to actin nitration, and mechanisms may differ between control and diabetic animals. Our findings also demonstrate that diabetes alters the ability of cerebral vessels to regulate CBF under basal and hypoxic conditions.
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The age-related deficit in LTP is associated with changes in perfusion and blood-brain barrier permeability. Neurobiol Aging 2012; 33:1005.e23-35. [DOI: 10.1016/j.neurobiolaging.2011.09.035] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 09/22/2011] [Accepted: 09/30/2011] [Indexed: 12/11/2022]
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Luh WM, Talagala SL, Li TQ, Bandettini PA. Pseudo-continuous arterial spin labeling at 7 T for human brain: estimation and correction for off-resonance effects using a Prescan. Magn Reson Med 2012; 69:402-10. [PMID: 22488568 DOI: 10.1002/mrm.24266] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Revised: 02/15/2012] [Accepted: 03/01/2012] [Indexed: 11/05/2022]
Abstract
Pseudo-continuous arterial spin labeling (ASL) can provide best signal-to-noise ratio efficiency with a sufficiently long tag at high fields such as 7 T, but it is very sensitive to off-resonance fields at the tagging location. Here, a robust Prescan procedure is demonstrated to estimate the pseudo-continuous ASL radiofrequency phase and gradients parameters required to compensate the off-resonance effects at each vessel location. The Prescan is completed in 1-2 min and is based on acquisition of label/control pair-wise ASL data as a function of the radiofrequency phase increment applied to the pseudo-continuous ASL train. It is shown that this approach can be used to acquire high quality whole-brain pseudo-continuous ASL perfusion data of the human brain at 7 T.
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Affiliation(s)
- Wen-Ming Luh
- Functional MRI Facility, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA.
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45
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Zaharchuk G. Arterial spin label imaging of acute ischemic stroke and transient ischemic attack. Neuroimaging Clin N Am 2012; 21:285-301, x. [PMID: 21640300 DOI: 10.1016/j.nic.2011.01.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Since acute stroke and transient ischemic attack (TIA) are disruptions of brain hemodynamics, perfusion neuroimaging might be of clinical utility. Recently, arterial spin labeling (ASL), a noncontrast perfusion method, has become clinically feasible. It has advantages compared to contrast bolus perfusion-weighted imaging (PWI) including lack of exposure to gadolinium, improved quantitation, and decreased sensitivity to susceptibility and motion. Drawbacks include reduced signal-to-noise and high sensitivity to arterial transit delays. However, this sensitivity can enable visualization of collateral flow. This article discusses ASL findings in patients with acute stroke and TIA, focusing on typical appearances, common artifacts, and comparisons with PWI.
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Affiliation(s)
- Greg Zaharchuk
- Stanford University Medical Center, Stanford University, 1201 Welch Road, Mailcode 5488, Stanford, CA 94305-5488, USA.
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46
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The Role of 3 Tesla MRA in the Detection of Intracranial Aneurysms. Int J Vasc Med 2012; 2012:792834. [PMID: 22292121 PMCID: PMC3265088 DOI: 10.1155/2012/792834] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Accepted: 10/09/2011] [Indexed: 12/01/2022] Open
Abstract
Intracranial aneurysms constitute a common pathological entity, affecting approximately 1–8% of the general population. Their early detection is essential for their prompt treatment. Digital subtraction angiography is considered the imaging method of choice. However, other noninvasive methodologies such as CTA and MRA have been employed in the investigation of patients with suspected aneurysms. MRA is a noninvasive angiographic modality requiring no radiation exposure. However, its sensitivity and diagnostic accuracy were initially inadequate. Several MRA techniques have been developed for overcoming all these drawbacks and for improving its sensitivity. 3D TOF MRA and contrast-enhanced MRA are the most commonly employed techniques. The introduction of 3 T magnetic field further increased MRA's sensitivity, allowing detection of aneurysms smaller than 3 mm. The development of newer MRA techniques may provide valuable information regarding the flow characteristics of an aneurysm. Meticulous knowledge of MRA's limitations and pitfalls is of paramount importance for avoiding any erroneous interpretation of its findings.
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Abstract
Perfusion MRI is a tool to assess the spatial distribution of microvascular blood flow. Arterial spin labeling (ASL) is shown here to be advantageous for quantification of cerebral microvascular blood flow (CBF) in rodents. This technique is today ready for assessment of a variety of murine models of human pathology including those associated with diffuse microvascular dysfunction. This chapter provides an introduction to the principles of CBF measurements by MRI along with a short overview over applications in which these measurements were found useful. The basics of commonly employed specific arterial spin-labeling techniques are described and theory is outlined in order to give the reader the ability to set up adequate post-processing tools. Three typical MR protocols for pulsed ASL on two different MRI systems are described in detail along with all necessary sequence parameters and technical requirements. The importance of the different parameters entering theory is discussed. Particular steps for animal preparation and maintenance during the experiment are given, since CBF regulation is sensitive to a number of experimental physiological parameters and influenced mainly by anesthesia and body temperature.
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48
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Koretsky AP. Early development of arterial spin labeling to measure regional brain blood flow by MRI. Neuroimage 2012; 62:602-7. [PMID: 22245338 DOI: 10.1016/j.neuroimage.2012.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 11/16/2011] [Accepted: 01/01/2012] [Indexed: 12/31/2022] Open
Abstract
Two major avenues of work converged in the late 1980's and early 1990's to give rise to brain perfusion MRI. The development of anatomical brain MRI quickly had as a major goal the generation of angiograms using tricks to label flowing blood in macroscopic vessels. These ideas were aimed at getting information about microcirculatory flow as well. Over the same time course the development of in vivo magnetic resonance spectroscopy had as its primary goal the assessment of tissue function and in particular, tissue energetics. For this the measurement of the delivery of water to tissue was critical for assessing tissue oxygenation and viability. The measurement of the washin/washout of "freely" diffusible tracers by spectroscopic based techniques pointed the way for quantitative approaches to measure regional blood flow by MRI. These two avenues came together in the development of arterial spin labeling (ASL) MRI techniques to measure regional cerebral blood flow. The early use of ASL to measure brain activation to help verify BOLD fMRI led to a rapid development of ASL based perfusion MRI. Today development and applications of regional brain blood flow measurements with ASL continues to be a major area of activity.
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Affiliation(s)
- Alan P Koretsky
- Laboratory of Functional and Molecular Imaging, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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49
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Fujiwara Y. [Clinical application of perfusion MR imaging using arterial spin labeling]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2012; 68:1063-1070. [PMID: 22975705 DOI: 10.6009/jjrt.2012_jsrt_68.8.1063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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50
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Jahanian H, Noll DC, Hernandez-Garcia L. B0 field inhomogeneity considerations in pseudo-continuous arterial spin labeling (pCASL): effects on tagging efficiency and correction strategy. NMR IN BIOMEDICINE 2011; 24:1202-1209. [PMID: 21387447 DOI: 10.1002/nbm.1675] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 12/15/2010] [Accepted: 12/16/2010] [Indexed: 05/30/2023]
Abstract
Pseudo-continuous arterial spin labeling (pCASL) is a very powerful technique to measure cerebral perfusion, which circumvents the problems affecting other continuous arterial spin labeling schemes, such as magnetization transfer and duty cycle. However, some variability in the tagging efficiency of the pCASL technique has been reported. This article investigates the effect of B(0) field inhomogeneity on the tagging efficiency of the pCASL pulse sequence as a possible cause of this variability. Both theory and simulated data predict that the efficiency of pseudo-continuous labeling pulses can be degraded in the presence of off-resonance effects. These findings are corroborated by human in vivo measurements of tagging efficiency. On the basis of this theoretical framework, a method utilizing B(0) field map information is proposed to correct for the possible loss in tagging efficiency of the pCASL pulse sequence. The efficiency of the proposed correction method is evaluated using numerical simulations and in vivo implementation. The data show that the proposed method can effectively recover the lost tagging efficiency and signal-to-noise ratio of pCASL caused by off-resonance effects.
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Affiliation(s)
- Hesamoddin Jahanian
- Functional MRI Laboratory, University of Michigan, 2360 Bonisteel Ave., Ann Arbor, MI, USA.
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