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Callewaert B, Jones EAV, Himmelreich U, Gsell W. Non-Invasive Evaluation of Cerebral Microvasculature Using Pre-Clinical MRI: Principles, Advantages and Limitations. Diagnostics (Basel) 2021; 11:diagnostics11060926. [PMID: 34064194 PMCID: PMC8224283 DOI: 10.3390/diagnostics11060926] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/16/2021] [Accepted: 05/17/2021] [Indexed: 12/11/2022] Open
Abstract
Alterations to the cerebral microcirculation have been recognized to play a crucial role in the development of neurodegenerative disorders. However, the exact role of the microvascular alterations in the pathophysiological mechanisms often remains poorly understood. The early detection of changes in microcirculation and cerebral blood flow (CBF) can be used to get a better understanding of underlying disease mechanisms. This could be an important step towards the development of new treatment approaches. Animal models allow for the study of the disease mechanism at several stages of development, before the onset of clinical symptoms, and the verification with invasive imaging techniques. Specifically, pre-clinical magnetic resonance imaging (MRI) is an important tool for the development and validation of MRI sequences under clinically relevant conditions. This article reviews MRI strategies providing indirect non-invasive measurements of microvascular changes in the rodent brain that can be used for early detection and characterization of neurodegenerative disorders. The perfusion MRI techniques: Dynamic Contrast Enhanced (DCE), Dynamic Susceptibility Contrast Enhanced (DSC) and Arterial Spin Labeling (ASL), will be discussed, followed by less established imaging strategies used to analyze the cerebral microcirculation: Intravoxel Incoherent Motion (IVIM), Vascular Space Occupancy (VASO), Steady-State Susceptibility Contrast (SSC), Vessel size imaging, SAGE-based DSC, Phase Contrast Flow (PC) Quantitative Susceptibility Mapping (QSM) and quantitative Blood-Oxygenation-Level-Dependent (qBOLD). We will emphasize the advantages and limitations of each strategy, in particular on applications for high-field MRI in the rodent's brain.
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Affiliation(s)
- Bram Callewaert
- Biomedical MRI Group, University of Leuven, Herestraat 49, bus 505, 3000 Leuven, Belgium; (B.C.); (W.G.)
- CMVB, Center for Molecular and Vascular Biology, University of Leuven, Herestraat 49, bus 911, 3000 Leuven, Belgium;
| | - Elizabeth A. V. Jones
- CMVB, Center for Molecular and Vascular Biology, University of Leuven, Herestraat 49, bus 911, 3000 Leuven, Belgium;
- CARIM, Maastricht University, Universiteitssingel 50, 6200 MD Maastricht, The Netherlands
| | - Uwe Himmelreich
- Biomedical MRI Group, University of Leuven, Herestraat 49, bus 505, 3000 Leuven, Belgium; (B.C.); (W.G.)
- Correspondence:
| | - Willy Gsell
- Biomedical MRI Group, University of Leuven, Herestraat 49, bus 505, 3000 Leuven, Belgium; (B.C.); (W.G.)
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Overview and Critical Appraisal of Arterial Spin Labelling Technique in Brain Perfusion Imaging. CONTRAST MEDIA & MOLECULAR IMAGING 2018; 2018:5360375. [PMID: 29853806 PMCID: PMC5964483 DOI: 10.1155/2018/5360375] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 04/11/2018] [Indexed: 12/02/2022]
Abstract
Arterial spin labelling (ASL) allows absolute quantification of CBF via a diffusible intrinsic tracer (magnetically labelled blood water) that disperses from the vascular system into neighbouring tissue. Thus, it can provide absolute CBF quantification, which eliminates the need for the contrast agent, and can be performed repeatedly. This review will focus on the common ASL acquisition techniques (continuous, pulsed, and pseudocontinuous ASL) and how ASL image quality might be affected by intrinsic factors that may bias the CBF measurements. We also provide suggestions to mitigate these risks, model appropriately the acquired signal, increase the image quality, and hence estimate the reliability of the CBF, which consists an important noninvasive biomarker. Emerging methodologies for extraction of new ASL-based biomarkers, such as arterial arrival time (AAT) and arterial blood volume (aBV), will be also briefly discussed.
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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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Bause J, Ehses P, Mirkes C, Shajan G, Scheffler K, Pohmann R. Quantitative and functional pulsed arterial spin labeling in the human brain at 9.4 t. Magn Reson Med 2016; 75:1054-63. [DOI: 10.1002/mrm.25671] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 02/04/2015] [Accepted: 02/05/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Jonas Bause
- Max Planck Institute for Biological Cybernetics, High‐Field Magnetic Resonance CenterTübingen Germany
- Graduate Training Center of Neuronal SciencesInternational Max Planck Research SchoolUniversity of TübingenTübingen Germany
| | - Philipp Ehses
- Max Planck Institute for Biological Cybernetics, High‐Field Magnetic Resonance CenterTübingen Germany
- Department of Biomedical Magnetic ResonanceUniversity of TübingenTübingen Germany
| | - Christian Mirkes
- Max Planck Institute for Biological Cybernetics, High‐Field Magnetic Resonance CenterTübingen Germany
- Department of Biomedical Magnetic ResonanceUniversity of TübingenTübingen Germany
| | - G. Shajan
- Max Planck Institute for Biological Cybernetics, High‐Field Magnetic Resonance CenterTübingen Germany
| | - Klaus Scheffler
- Max Planck Institute for Biological Cybernetics, High‐Field Magnetic Resonance CenterTübingen Germany
- Department of Biomedical Magnetic ResonanceUniversity of TübingenTübingen Germany
| | - Rolf Pohmann
- Max Planck Institute for Biological Cybernetics, High‐Field Magnetic Resonance CenterTübingen Germany
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A neuroradiologist's guide to arterial spin labeling MRI in clinical practice. Neuroradiology 2015; 57:1181-202. [PMID: 26351201 PMCID: PMC4648972 DOI: 10.1007/s00234-015-1571-z] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/05/2015] [Indexed: 01/01/2023]
Abstract
Arterial spin labeling (ASL) is a non-invasive MRI technique to measure cerebral blood flow (CBF). This review provides a practical guide and overview of the clinical applications of ASL of the brain, as well its potential pitfalls. The technical and physiological background is also addressed. At present, main areas of interest are cerebrovascular disease, dementia and neuro-oncology. In cerebrovascular disease, ASL is of particular interest owing to its quantitative nature and its capability to determine cerebral arterial territories. In acute stroke, the source of the collateral blood supply in the penumbra may be visualised. In chronic cerebrovascular disease, the extent and severity of compromised cerebral perfusion can be visualised, which may be used to guide therapeutic or preventative intervention. ASL has potential for the detection and follow-up of arteriovenous malformations. In the workup of dementia patients, ASL is proposed as a diagnostic alternative to PET. It can easily be added to the routinely performed structural MRI examination. In patients with established Alzheimer’s disease and frontotemporal dementia, hypoperfusion patterns are seen that are similar to hypometabolism patterns seen with PET. Studies on ASL in brain tumour imaging indicate a high correlation between areas of increased CBF as measured with ASL and increased cerebral blood volume as measured with dynamic susceptibility contrast-enhanced perfusion imaging. Major advantages of ASL for brain tumour imaging are the fact that CBF measurements are not influenced by breakdown of the blood–brain barrier, as well as its quantitative nature, facilitating multicentre and longitudinal studies.
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Hare HV, Blockley NP, Gardener AG, Clare S, Bulte DP. Investigating the field-dependence of the Davis model: Calibrated fMRI at 1.5, 3 and 7T. Neuroimage 2015; 112:189-196. [PMID: 25783207 PMCID: PMC4410945 DOI: 10.1016/j.neuroimage.2015.02.068] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 01/16/2015] [Accepted: 02/25/2015] [Indexed: 10/28/2022] Open
Abstract
Gas calibrated fMRI in its most common form uses hypercapnia in conjunction with the Davis model to quantify relative changes in the cerebral rate of oxygen consumption (CMRO2) in response to a functional stimulus. It is most commonly carried out at 3T but, as 7T research scanners are becoming more widespread and the majority of clinical scanners are still 1.5T systems, it is important to investigate whether the model used remains accurate across this range of field strengths. Ten subjects were scanned at 1.5, 3 and 7T whilst performing a bilateral finger-tapping task as part of a calibrated fMRI protocol, and the results were compared to a detailed signal model. Simulations predicted an increase in value and variation in the calibration parameter M with field strength. Two methods of defining experimental regions of interest (ROIs) were investigated, based on (a) BOLD signal and (b) BOLD responses within grey matter only. M values from the latter ROI were in closer agreement with theoretical predictions; however, reassuringly, ROI choice had less impact on CMRO2 than on M estimates. Relative changes in CMRO2 during motor tasks at 3 and 7T were in good agreement but were over-estimated at 1.5T as a result of the lower signal to noise ratio. This result is encouraging for future studies at 7T, but also highlights the impact of imaging and analysis choices (such as ASL sequence and ROI definition) on the calibration parameter M and on the calculation of CMRO2.
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Affiliation(s)
- Hannah V Hare
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
| | - Nicholas P Blockley
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Alexander G Gardener
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Stuart Clare
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Daniel P Bulte
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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Dahmoush HM, Vossough A, Roberts TPL. Pediatric high-field magnetic resonance imaging. Neuroimaging Clin N Am 2012; 22:297-313, xi. [PMID: 22548934 DOI: 10.1016/j.nic.2012.02.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
High-field 3 T magnetic resonance (MR) imaging provides greater signal-to-noise ratio (SNR) compared with 1.5 T systems. Various MR imaging clinical applications in children can benefit from improvements resulting from this increased SNR. High-resolution imaging of the brain, arterial spin labeling perfusion imaging, diffusion imaging, MR spectroscopy, and imaging of small anatomic parts are some areas in which these improvements can increase our clinical diagnostic capabilities. However, challenges inherent to 3 T imaging become more relevant in children. The use of 3 T imaging in children has allowed better diagnostic efficacy in neuroimaging, but certain technique modifications may be required for optimal imaging.
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Affiliation(s)
- Hisham M Dahmoush
- Neuroradiology Section, Department of Radiology, Children's Hospital of Philadelphia, Wood 2115, 324 South 34th Street, Philadelphia, PA 19104, USA
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Assessment of cerebral perfusion from bypass arteries using magnetic resonance regional perfusion imaging in patients with moyamoya disease. Jpn J Radiol 2010; 28:746-53. [DOI: 10.1007/s11604-010-0507-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Accepted: 08/24/2010] [Indexed: 11/27/2022]
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Propofol allows precise quantitative arterial spin labelling functional magnetic resonance imaging in the rat. Neuroimage 2010; 51:1395-404. [PMID: 20304075 DOI: 10.1016/j.neuroimage.2010.03.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 02/19/2010] [Accepted: 03/09/2010] [Indexed: 11/24/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) techniques highlight cerebral vascular responses which are coupled to changes in neural activation. However, two major difficulties arise when employing these techniques in animal studies. First is the disturbance of cerebral blood flow due to anaesthesia and second is the difficulty of precise reproducible quantitative measurements. These difficulties were surmounted in the current study by using propofol and quantitative arterial spin labelling (QASL) to measure relative cerebral blood volume of labelled water (rCBV(lw),) mean transit time (MTT) and capillary transit time (CTT). The ASL method was applied to measure the haemodynamic response in the primary somatosensory cortex following forepaw stimulation in the rat. Following stimulation an increase in signal intensity and rCBV(lw) was recorded, this was accompanied by a significant decrease in MTT (1.97+/-0.06s to 1.44+/-0.04s) and CTT (1.76+/-0.06s to 1.39+/-0.07s). Two animals were scanned repeatedly on two different experimental days. Stimulation in the first animal was applied to the same forepaw during the initial and repeat scan. In the second animal stimulation was applied to different forepaws on the first and second days. The control and activated ASL signal intensities, rCBVlw on both days were almost identical in both animals. The basal MTT and CTT during the second scan were also very similar to the values obtained during the first scan. The MTT recorded from the animal that underwent stimulation to the same paw during both scanning sessions was very similar on the first and second days. In conclusion, propofol induces little physiological disturbance and holds potential for longitudinal QASL fMRI studies.
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Gardener A, Gowland P, Francis S. Implementation of quantitative perfusion imaging using pulsed arterial spin labeling at ultra-high field. Magn Reson Med 2009; 61:874-82. [DOI: 10.1002/mrm.21796] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Petersen ET, Zimine I, Ho YCL, Golay X. Non-invasive measurement of perfusion: a critical review of arterial spin labelling techniques. Br J Radiol 2006; 79:688-701. [PMID: 16861326 DOI: 10.1259/bjr/67705974] [Citation(s) in RCA: 244] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The non-invasive nature of arterial spin labelling (ASL) has opened a unique window into human brain function and perfusion physiology. High spatial and temporal resolution makes the technique very appealing not only for the diagnosis of vascular diseases, but also in basic neuroscience where the aim is to develop a more comprehensive picture of the physiological events accompanying neuronal activation. However, low signal-to-noise ratio and the complexity of flow quantification make ASL one of the more demanding disciplines within MRI. In this review, the theoretical background and main implementations of ASL are revisited. In particular, the perfusion quantification methods, including the problems and pitfalls involved, are thoroughly discussed in this article. Finally, a brief summary of applications is provided.
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Affiliation(s)
- E T Petersen
- Department of Neuroradiology, National Neuroscience Institute, Singapore
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Golay X, Petersen ET. Arterial Spin Labeling: Benefits and Pitfalls of High Magnetic Field. Neuroimaging Clin N Am 2006; 16:259-68, x. [PMID: 16731365 DOI: 10.1016/j.nic.2006.02.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Arterial spin labeling (ASL) techniques are MR imaging methods designed to measure the endogenous perfusion signal coming from arterial blood by manipulation of its magnetization. These methods are based on the subtraction of two consecutively acquired images: one acquired after preparation of the arterial blood magnetization upstream to the area of interest, and the second without any manipulation of its arterial magnetization. The subtraction of both images provides information on the perfusion of the tissue present in the slice of interest. Because ASL is a very low SNR technique, the shift from 1.5 T to 3.0 T should be regarded as a great way to increase signal-to-noise ratio (SNR). Furthermore, the concomitant increase in blood T(1) should improve the SNR of ASL further. Other effects related to poorer magnetic filed homogeneities and reduced T(2) relaxation times, however, will counterbalance both effects partially. In this article, the pros and cons of the use of ASL at high field are summarized, after a brief description of the major techniques used and their theoretical limitations. Finally, a summary of the few existing dedicated ASL perfusion techniques available are presented.
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Affiliation(s)
- Xavier Golay
- Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, 11 Biopolis Way, Singapore 138667.
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Abstract
Modern functional neuroimaging techniques, including functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and optical imaging of intrinsic signals (OIS), rely on a tight coupling between neural activity and cerebral blood flow (CBF) to visualize brain activity using CBF as a surrogate marker. Because CBF is a uniquely defined physiological parameter, fMRI techniques based on CBF contrast have the advantage of being specific to tissue signal change, and the potential to provide more direct and quantitative measures of brain activation than blood oxygenation level-dependent (BOLD)- or cerebral blood volume (CBV)-based techniques. The changes in CBF elicited by increased neural activity are an excellent index of the magnitude of electrical activity. Increases in CBF are more closely localized to the foci of increased electrical activity, and occur more promptly to the stimulus than BOLD- or CBV-based contrast. In addition, CBF-based fMRI is less affected by confounds from venous drainage common to BOLD. Animal studies of brain activation have yielded considerable insights into the advantages of CBF-based fMRI. Based on results provided by animal studies, CBF fMRI may offer a means of better assessing the magnitude, spatial extent, and temporal response of neural activity, and may be more specific to tissue state. These properties are expected to be particularly useful for longitudinal and quantitative fMRI studies.
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Affiliation(s)
- Afonso C Silva
- Cerebral Microcirculation Unit, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland 20892, USA.
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Abstract
Originally developed for increased scanning velocity in cardiac imaging, parallel imaging (PI) techniques have recently also been applied for the reduction of artifacts in single-shot techniques. In functional brain imaging (fMRI) techniques, PI has been used for several purposes. It has been applied to reduce the distortions caused by the length of the echo-planar imaging readout, diminution of the gradient-related acoustic noise, as a means to increase acquisition speed or to increase the achievable brain coverage per unit time. In this article, the different applications of PI techniques in fMRI are reviewed, together with the basic theoretical background and the recently developed hardware necessary to achieve rapid, high signal-to-noise ratio PI-fMRI.
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Affiliation(s)
- Xavier Golay
- Department of Neuroradiology, National Neuroscience Institute, Singapore.
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Abstract
Arterial spin labeling is a magnetic resonance method for the measurement of cerebral blood flow. In its simplest form, the perfusion contrast in the images gathered by this technique comes from the subtraction of two successively acquired images: one with, and one without, proximal labeling of arterial water spins after a small delay time. Over the last decade, the method has moved from the experimental laboratory to the clinical environment. Furthermore, numerous improvements, ranging from new pulse sequence implementations to extensive theoretical studies, have broadened its reach and extended its potential applications. In this review, the multiple facets of this powerful yet difficult technique are discussed. Different implementations are compared, the theoretical background is summarized, and potential applications of various implementations in research as well as in the daily clinical routine are proposed. Finally, a summary of the new developments and emerging techniques in this field is provided.
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Affiliation(s)
- Xavier Golay
- Department of Neuroradiology, National Neuroscience Institute, Singapore.
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Petty MA, Neumann-Haefelin C, Kalisch J, Sarhan S, Wettstein JG, Juretschke HP. In vivo neuroprotective effects of ACEA 1021 confirmed by magnetic resonance imaging in ischemic stroke. Eur J Pharmacol 2003; 474:53-62. [PMID: 12909195 DOI: 10.1016/s0014-2999(03)02002-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The neuroprotective activity of ACEA 1021 (5-nitro-6,7-dichloro-1,4-dihydro-2,3-quinoxalinedione; licostinel), a selective antagonist at the strychnine-insensitive glycine site associated with the NMDA receptor complex, has been investigated in various models of focal cerebral ischemia. In isoflurane-anaesthesised Wistar rats with permanent ipsilateral carotid artery ligation and transient middle cerebral artery occlusion (duration of occlusion, 2 h) followed by reperfusion (24 h), intravenous administration of ACEA 1021 (bolus: 10 mg/kg, 15 min after the onset of middle cerebral artery occlusion; infusion: 7 mg/kg/h for 6 h beginning 30 min after occlusion of the artery) produced a 32% reduction in infarct volume. Similarly, in Sprague-Dawley rats with transient middle cerebral artery occlusion (2 h) followed by 24 h of reperfusion, identical treatment with ACEA 1021 decreased infarct size by 39%. Magnetic resonance imaging (MRI) confirmed these effects in the transient model, in that infarct volume observed using apparent diffusion coefficient (ADC) maps was significantly smaller after 24 h in the ACEA 1021-treated rats compared with Tris-treated controls. Furthermore, the increase in perfusion signal intensity after reperfusion was more pronounced in the ACEA 1021-treated rats than in controls. In Fisher 344 rats with permanent occlusion of the middle cerebral artery, ACEA 1021 induced a dose-related decrease in infarct volume, which was associated with an improvement in neurological outcome as measured by the rope suspension procedure. Administration of the same dose regimen, as above, in Fisher rats with permanent middle cerebral artery occlusion reduced infarct volume by 68%. This dose was as effective when administration was delayed for 2 h. In mice with permanent middle cerebral artery occlusion, ACEA 1021 (5 mg/kg, i.v., 5 min after occlusion; 30 mg/kg, s.c., 1 and 4 h post-middle cerebral artery occlusion) decreased infarct size by 42%. The consistent anti-ischemic effects of ACEA 1021 make it a valuable compound for exploratory stroke research.
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Affiliation(s)
- Margaret A Petty
- Systems Pharmacology, Mail Stop 303A, Aventis Pharmaceuticals Inc., Route 202-206, PO Box 6800, Bridgewater, NJ 08807, USA.
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Stuber M, Börnert P, Spuentrup E, Botnar RM, Manning WJ. Selective three-dimensional visualization of the coronary arterial lumen using arterial spin tagging. Magn Reson Med 2002; 47:322-9. [PMID: 11810676 DOI: 10.1002/mrm.10042] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Conventional coronary magnetic resonance angiography (MRA) techniques display the coronary blood-pool along with the surrounding structures, including the myocardium, the ventricular and atrial blood-pool, and the great vessels. This representation of the coronary lumen is not directly analogous to the information provided by x-ray coronary angiography, in which the coronary lumen displayed by iodinated contrast agent is seen. Analogous "luminographic" data may be obtained using MR arterial spin tagging (projection coronary MRA) techniques. Such an approach was implemented using a 2D selective "pencil" excitation for aortic spin tagging in concert with a 3D interleaved segmented spiral imaging sequence with free-breathing, and real-time navigator technology. This technique allows for selective 3D visualization of the coronary lumen blood-pool, while signal from the surrounding structures is suppressed.
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Affiliation(s)
- Matthias Stuber
- Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA.
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Hendrich KS, Kochanek PM, Melick JA, Schiding JK, Statler KD, Williams DS, Marion DW, Ho C. Cerebral perfusion during anesthesia with fentanyl, isoflurane, or pentobarbital in normal rats studied by arterial spin-labeled MRI. Magn Reson Med 2001; 46:202-6. [PMID: 11443729 DOI: 10.1002/mrm.1178] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The influence of anesthetic agents on cerebral blood flow (CBF) was tested in normal rats. CBF is quantified with arterial spin-labeled MRI in rats anesthetized with either an opiate (fentanyl), a potent inhalation anesthetic agent (isoflurane), or a barbiturate (pentobarbital) using doses commonly employed in experimental paradigms. CBF values were found to be about 2.5-3 times lower in most regions analyzed during anesthesia with either fentanyl (with N(2)O/O(2)) or pentobarbital vs. isoflurane (with N(2)O/O(2)), in agreement with findings utilizing invasive measurement techniques. CBF was heterogeneous in rats anesthetized with isoflurane (with N(2)O/O(2)), but relatively homogeneous in rats anesthetized with either fentanyl (with N(2)O/O(2)) or pentobarbital, also in agreement with studies using other techniques. Magn Reson Med 46:202-206, 2001.
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Affiliation(s)
- K S Hendrich
- Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, PA 15260, USA
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