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Kim J, Lee H, Oh SS, Jang J, Lee H. Automated Quantification of Total Cerebral Blood Flow from Phase-Contrast MRI and Deep Learning. JOURNAL OF IMAGING INFORMATICS IN MEDICINE 2024; 37:563-574. [PMID: 38343224 PMCID: PMC11031545 DOI: 10.1007/s10278-023-00948-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/06/2023] [Accepted: 10/25/2023] [Indexed: 04/20/2024]
Abstract
Knowledge of input blood to the brain, which is represented as total cerebral blood flow (tCBF), is important in evaluating brain health. Phase-contrast (PC) magnetic resonance imaging (MRI) enables blood velocity mapping, allowing for noninvasive measurements of tCBF. In the procedure, manual selection of brain-feeding arteries is an essential step, but is time-consuming and often subjective. Thus, the purpose of this work was to develop and validate a deep learning (DL)-based technique for automated tCBF quantifications. To enhance the DL segmentation performance on arterial blood vessels, in the preprocessing step magnitude and phase images of PC MRI were multiplied several times. Thereafter, a U-Net was trained on 218 images for three-class segmentation. Network performance was evaluated in terms of the Dice coefficient and the intersection-over-union (IoU) on 40 test images, and additionally, on externally acquired 20 datasets. Finally, tCBF was calculated from the DL-predicted vessel segmentation maps, and its accuracy was statistically assessed with the correlation of determination (R2), the intraclass correlation coefficient (ICC), paired t-tests, and Bland-Altman analysis, in comparison to manually derived values. Overall, the DL segmentation network provided accurate labeling of arterial blood vessels for both internal (Dice=0.92, IoU=0.86) and external (Dice=0.90, IoU=0.82) tests. Furthermore, statistical analyses for tCBF estimates revealed good agreement between automated versus manual quantifications in both internal (R2=0.85, ICC=0.91, p=0.52) and external (R2=0.88, ICC=0.93, p=0.88) test groups. The results suggest feasibility of a simple and automated protocol for quantifying tCBF from neck PC MRI and deep learning.
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Affiliation(s)
- Jinwon Kim
- School of Electronic and Electrical Engineering, Kyungpook National University, IT1-603, Daehak-ro 80, Buk-gu, Daegu, 41075, Republic of Korea
| | - Hyebin Lee
- Department of Radiology, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sung Suk Oh
- Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI hub), Daegu, Republic of Korea
| | - Jinhee Jang
- Department of Radiology, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
| | - Hyunyeol Lee
- School of Electronic and Electrical Engineering, Kyungpook National University, IT1-603, Daehak-ro 80, Buk-gu, Daegu, 41075, Republic of Korea.
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2
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Biondetti E, Chiarelli AM, Germuska M, Lipp I, Villani A, Caporale AS, Patitucci E, Murphy K, Tomassini V, Wise RG. Breath-hold BOLD fMRI without CO 2 sampling enables estimation of venous cerebral blood volume: potential use in normalization of stimulus-evoked BOLD fMRI data. Neuroimage 2024; 285:120492. [PMID: 38070840 DOI: 10.1016/j.neuroimage.2023.120492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 10/30/2023] [Accepted: 12/06/2023] [Indexed: 01/13/2024] Open
Abstract
BOLD fMRI signal has been used in conjunction with vasodilatory stimulation as a marker of cerebrovascular reactivity (CVR): the relative change in cerebral blood flow (CBF) arising from a unit change in the vasodilatory stimulus. Using numerical simulations, we demonstrate that the variability in the relative BOLD signal change induced by vasodilation is strongly influenced by the variability in deoxyhemoglobin-containing cerebral blood volume (CBV), as this source of variability is likely to be more prominent than that of CVR. It may, therefore, be more appropriate to describe the relative BOLD signal change induced by an isometabolic vasodilation as a proxy of deoxygenated CBV (CBVdHb) rather than CVR. With this in mind, a new method was implemented to map a marker of CBVdHb, termed BOLD-CBV, based on the normalization of voxel-wise BOLD signal variation by an estimate of the intravascular venous BOLD signal from voxels filled with venous blood. The intravascular venous BOLD signal variation, recorded during repeated breath-holding, was extracted from the superior sagittal sinus in a cohort of 27 healthy volunteers and used as a regressor across the whole brain, yielding maps of BOLD-CBV. In the same cohort, we demonstrated the potential use of BOLD-CBV for the normalization of stimulus-evoked BOLD fMRI by comparing group-level BOLD fMRI responses to a visuomotor learning task with and without the inclusion of voxel-wise vascular covariates of BOLD-CBV and the BOLD signal change per mmHg variation in end-tidal carbon dioxide (BOLD-CVR). The empirical measure of BOLD-CBV accounted for more between-subject variability in the motor task-induced BOLD responses than BOLD-CVR estimated from end-tidal carbon dioxide recordings. The new method can potentially increase the power of group fMRI studies by including a measure of vascular characteristics and has the strong practical advantage of not requiring experimental measurement of end-tidal carbon dioxide, unlike traditional methods to estimate BOLD-CVR. It also more closely represents a specific physiological characteristic of brain vasculature than BOLD-CVR, namely blood volume.
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Affiliation(s)
- Emma Biondetti
- Department of Neurosciences, Imaging, and Clinical Sciences, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy; Institute for Advanced Biomedical Technologies, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy.
| | - Antonio Maria Chiarelli
- Department of Neurosciences, Imaging, and Clinical Sciences, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy; Institute for Advanced Biomedical Technologies, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy
| | - Michael Germuska
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom
| | - Ilona Lipp
- Department of Neurophysics, Max Planck Institute for Human Cognitive & Brain Sciences, Leipzig, Germany; Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK
| | - Alessandro Villani
- Department of Neurosciences, Imaging, and Clinical Sciences, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy; Institute for Advanced Biomedical Technologies, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy
| | - Alessandra S Caporale
- Department of Neurosciences, Imaging, and Clinical Sciences, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy; Institute for Advanced Biomedical Technologies, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy
| | - Eleonora Patitucci
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK
| | - Kevin Murphy
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom
| | - Valentina Tomassini
- Department of Neurosciences, Imaging, and Clinical Sciences, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy; Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK; MS Centre, Neurology Unit, 'SS. Annunziata' University Hospital, Chieti, Italy; Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, UK; Helen Durham Centre for Neuroinflammation, University Hospital of Wales, Cardiff, UK
| | - Richard G Wise
- Department of Neurosciences, Imaging, and Clinical Sciences, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy; Institute for Advanced Biomedical Technologies, 'G. D'Annunzio' University of Chieti-Pescara, Chieti, Italy; Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, UK
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3
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Deckers PT, Siero JCW, Mensink MO, Kronenburg A, Braun KPJ, van der Zwan A, Bhogal AA. Anesthesia Depresses Cerebrovascular Reactivity to Acetazolamide in Pediatric Moyamoya Vasculopathy. J Clin Med 2023; 12:4393. [PMID: 37445429 DOI: 10.3390/jcm12134393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/14/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
Measurements of cerebrovascular reactivity (CVR) are essential for treatment decisions in moyamoya vasculopathy (MMV). Since MMV patients are often young or cognitively impaired, anesthesia is commonly used to limit motion artifacts. Our aim was to investigate the effect of anesthesia on the CVR in pediatric MMV. We compared the CVR with multidelay-ASL and BOLD MRI, using acetazolamide as a vascular stimulus, in all awake and anesthesia pediatric MMV scans at our institution. Since a heterogeneity in disease and treatment influences the CVR, we focused on the (unaffected) cerebellum. Ten awake and nine anesthetized patients were included. The post-acetazolamide CBF and ASL-CVR were significantly lower in anesthesia patients (47.1 ± 15.4 vs. 61.4 ± 12.1, p = 0.04; 12.3 ± 8.4 vs. 23.7 ± 12.2 mL/100 g/min, p = 0.03, respectively). The final BOLD-CVR increase (0.39 ± 0.58 vs. 3.6 ± 1.2% BOLD-change (mean/SD), p < 0.0001), maximum slope of increase (0.0050 ± 0.0040%/s vs. 0.017 ± 0.0059%, p < 0.0001), and time to maximum BOLD-increase (~463 ± 136 and ~697 ± 144 s, p = 0.0028) were all significantly lower in the anesthesia group. We conclude that the response to acetazolamide is distinctively different between awake and anesthetized MMV patients, and we hypothesize that these findings can also apply to other diseases and methods of measuring CVR under anesthesia. Considering that treatment decisions heavily depend on CVR status, caution is warranted when assessing CVR under anesthesia.
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Affiliation(s)
- Pieter T Deckers
- Department of Neurosurgery, Universitair Medisch Centrum Utrecht, 3584 CX Utrecht, The Netherlands
- Department of Radiology and Nuclear Medicine, Meander Medisch Centrum, 3813 TZ Amersfoort, The Netherlands
| | - Jeroen C W Siero
- Department of Radiology, Universitair Medisch Centrum Utrecht, 3584 CX Utrecht, The Netherlands
- Spinoza Center for Neuroimaging, 1105 BK Amsterdam, The Netherlands
| | - Maarten O Mensink
- Pediatric Anesthesiology, Prinses Máxima Centrum, 3584 CS Utrecht, The Netherlands
| | - Annick Kronenburg
- Department of Neurosurgery, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
- Department of Neurosurgery, Haaglanden Medical Center, 2512 VA The Hague, The Netherlands
| | - Kees P J Braun
- Department of Pediatric Neurology, Wilhelmina Children's Hospital, Universitair Medisch Centrum Utrecht, 3584 CX Utrecht, The Netherlands
| | - Albert van der Zwan
- Department of Neurosurgery, Universitair Medisch Centrum Utrecht, 3584 CX Utrecht, The Netherlands
| | - Alex A Bhogal
- Department of Radiology, Universitair Medisch Centrum Utrecht, 3584 CX Utrecht, The Netherlands
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Amemiya S, Takao H, Watanabe Y, Miyawaki S, Koizumi S, Saito N, Abe O. Reliability and Sensitivity to Alterered Hemodynamics Measured with Resting-state fMRI Metrics: Comparison with 123I-IMP SPECT. Neuroimage 2022; 263:119654. [PMID: 36180009 DOI: 10.1016/j.neuroimage.2022.119654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/16/2022] [Accepted: 09/26/2022] [Indexed: 11/24/2022] Open
Abstract
Blood oxygenation level-dependent (BOLD) contrast is sensitive to local hemodynamic changes and thus is applicable to imaging perfusion or vascular reactivity. However, knowledge about its measurement characteristics compared to reference standard perfusion imaging is limited. This study longitudinally evaluated perfusion in patients with steno-occlusive disease using resting-state functional MRI (rsfMRI) acquired before and within nine days of anterior circulation revascularization in patients with large cerebral artery steno-occlusive diseases. The reliability and sensitivity to longitudinal changes of rsfMRI temporal correlation (Rc) and time delay (TDc) relative to the cerebellar signal were examined voxel-wise in comparison with single-photon emission CT (SPECT) cerebral blood flow (CBF) using the within-subject standard deviation (Sw) and intraclass correlation coefficients (ICCs). For statistical comparisons, the standard deviation (SD) of longitudinal changes within the cerebellum, the number of voxels with significant changes in the left middle cerebral artery territory ipsilateral to surgery, and their average changes relative to the cerebellar SD were evaluated. The test-retest reliability of the fMRI metrics was also similarly evaluated using the human connectome project (HCP) healthy young adult dataset. The test-retest time interval was 31 ± 18 days. Test-retest reliability was significantly higher for SPECT (cerebellar SD: -2.59 ± 0.20) than for fMRI metrics (cerebellar SD: Rc, -2.34 ± 0.24, p = 0.04; TDc, -2.19 ± 0.21, p = 0.003). Sensitivity to postoperative changes, which was evaluated as the number of voxels, was significantly higher for fMRI TDc (8.78 ± 0.72) than for Rc (7.42 ± 1.48, p = 0.03) or SPECT CBF (6.88 ± 0.67, p < 0.001). The ratio between the average Rc, TDc, and SPECT CBF changes within the left MCA target region and cerebellar SD was also significantly higher for fMRI TDc (1.21 ± 0.79) than Rc (0.48 ± 0.94, p = 0.006) or SPECT CBF (0.23 ± 0.57, p = 0.001). The measurement variability of time delay was also larger than that of temporal correlation in HCP data within the cerebellum (t = -8.7, p < 0.001) or in the whole-brain (t = -27.4, p < 0.001) gray matter. These data suggest that fMRI time delay is more sensitive to the hemodynamic changes than SPECT CBF, although the reliability is lower. The implication for fMRI connectivity studies is that temporal correlation can be significantly decreased due to altered hemodynamics, even in cases with normal CBF.
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Affiliation(s)
- Shiori Amemiya
- Department of Radiology, Graduate School of Medicine, University of Tokyo, Tokyo, JAPAN.
| | - Hidemasa Takao
- Department of Radiology, Graduate School of Medicine, University of Tokyo, Tokyo, JAPAN
| | - Yusuke Watanabe
- Department of Radiology, Graduate School of Medicine, University of Tokyo, Tokyo, JAPAN
| | - Satoru Miyawaki
- Department of Neurosurgery, Graduate School of Medicine, University of Tokyo, Tokyo, JAPAN
| | - Satoshi Koizumi
- Department of Neurosurgery, Graduate School of Medicine, University of Tokyo, Tokyo, JAPAN
| | - Nobuhito Saito
- Department of Neurosurgery, Graduate School of Medicine, University of Tokyo, Tokyo, JAPAN
| | - Osamu Abe
- Department of Radiology, Graduate School of Medicine, University of Tokyo, Tokyo, JAPAN
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5
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Schneider SC, Archila-Meléndez ME, Göttler J, Kaczmarz S, Zott B, Priller J, Kallmayer M, Zimmer C, Sorg C, Preibisch C. Resting-state BOLD functional connectivity depends on the heterogeneity of capillary transit times in the human brain A combined lesion and simulation study about the influence of blood flow response timing. Neuroimage 2022; 255:119208. [PMID: 35427773 DOI: 10.1016/j.neuroimage.2022.119208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 02/23/2022] [Accepted: 04/11/2022] [Indexed: 11/25/2022] Open
Abstract
Functional connectivity (FC) derived from blood oxygenation level dependent (BOLD) functional magnetic resonance imaging at rest (rs-fMRI), is commonly interpreted as indicator of neuronal connectivity. In a number of brain disorders, however, metabolic, vascular, and hemodynamic impairments can be expected to alter BOLD-FC independently from neuronal activity. By means of a neurovascular coupling (NVC) model of BOLD-FC, we recently demonstrated that aberrant timing of cerebral blood flow (CBF) responses may influence BOLD-FC. In the current work, we support and extend this finding by empirically linking BOLD-FC with capillary transit time heterogeneity (CTH), which we consider as an indicator of delayed and broadened CBF responses. We assessed 28 asymptomatic patients with unilateral high-grade internal carotid artery stenosis (ICAS) as a hemodynamic lesion model with largely preserved neurocognitive functioning and 27 age-matched healthy controls. For each participant, we obtained rs-fMRI, arterial spin labeling, and dynamic susceptibility contrast MRI to study the dependence of left-right homotopic BOLD-FC on local perfusion parameters. Additionally, we investigated the dependency of BOLD-FC on CBF response timing by detailed simulations. Homotopic BOLD-FC was negatively associated with increasing CTH differences between homotopic brain areas. This relation was more pronounced in asymptomatic ICAS patients even after controlling for baseline CBF and relative cerebral blood volume influences. These findings match simulation results that predict an influence of delayed and broadened CBF responses on BOLD-FC. Results demonstrate that increasing CTH differences between homotopic brain areas lead to BOLD-FC reductions. Simulations suggest that CTH increases correspond to broadened and delayed CBF responses to fluctuations in ongoing neuronal activity.
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Affiliation(s)
- Sebastian C Schneider
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Neuroradiology, Ismaningerstr. 22, 81675, Munich, Germany; Technical University of Munich, School of Medicine, Klinikum rechts der Isar, TUM Neuroimaging Center, Ismaningerstr. 22, 81675, Munich, Germany
| | - Mario E Archila-Meléndez
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Neuroradiology, Ismaningerstr. 22, 81675, Munich, Germany; Technical University of Munich, School of Medicine, Klinikum rechts der Isar, TUM Neuroimaging Center, Ismaningerstr. 22, 81675, Munich, Germany
| | - Jens Göttler
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Neuroradiology, Ismaningerstr. 22, 81675, Munich, Germany; Technical University of Munich, School of Medicine, Klinikum rechts der Isar, TUM Neuroimaging Center, Ismaningerstr. 22, 81675, Munich, Germany
| | - Stephan Kaczmarz
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Neuroradiology, Ismaningerstr. 22, 81675, Munich, Germany; Technical University of Munich, School of Medicine, Klinikum rechts der Isar, TUM Neuroimaging Center, Ismaningerstr. 22, 81675, Munich, Germany; Philips GmbH Market DACH, Hamburg, Germany
| | - Benedikt Zott
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Neuroradiology, Ismaningerstr. 22, 81675, Munich, Germany; Technical University of Munich, School of Medicine, Klinikum rechts der Isar, TUM Neuroimaging Center, Ismaningerstr. 22, 81675, Munich, Germany
| | - Josef Priller
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Psychiatry, Ismaningerstr. 22, 81675, Munich, Munich, Germany
| | - Michael Kallmayer
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Vascular and Endovascular Surgery, Ismaningerstr. 22, 81675, Munich, Munich, Germany
| | - Claus Zimmer
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Neuroradiology, Ismaningerstr. 22, 81675, Munich, Germany
| | - Christian Sorg
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Neuroradiology, Ismaningerstr. 22, 81675, Munich, Germany; Technical University of Munich, School of Medicine, Klinikum rechts der Isar, TUM Neuroimaging Center, Ismaningerstr. 22, 81675, Munich, Germany
| | - Christine Preibisch
- Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Neuroradiology, Ismaningerstr. 22, 81675, Munich, Germany; Technical University of Munich, School of Medicine, Klinikum rechts der Isar, TUM Neuroimaging Center, Ismaningerstr. 22, 81675, Munich, Germany; Technical University of Munich, School of Medicine, Klinikum rechts der Isar, Department of Neurology, Ismaningerstr. 22, 81675, Munich, Munich, Germany.
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6
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Rossetti GM, d'Avossa G, Rogan M, Macdonald JH, Oliver SJ, Mullins PG. Reversal of neurovascular coupling in the default mode network: Evidence from hypoxia. J Cereb Blood Flow Metab 2021; 41:805-818. [PMID: 32538282 PMCID: PMC7983511 DOI: 10.1177/0271678x20930827] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Local changes in cerebral blood flow are thought to match changes in neuronal activity, a phenomenon termed neurovascular coupling. Hypoxia increases global resting cerebral blood flow, but regional cerebral blood flow (rCBF) changes are non-uniform. Hypoxia decreases baseline rCBF to the default mode network (DMN), which could reflect either decreased neuronal activity or altered neurovascular coupling. To distinguish between these hypotheses, we characterized the effects of hypoxia on baseline rCBF, task performance, and the hemodynamic (BOLD) response to task activity. During hypoxia, baseline CBF increased across most of the brain, but decreased in DMN regions. Performance on memory recall and motion detection tasks was not diminished, suggesting task-relevant neuronal activity was unaffected. Hypoxia reversed both positive and negative task-evoked BOLD responses in the DMN, suggesting hypoxia reverses neurovascular coupling in the DMN of healthy adults. The reversal of the BOLD response was specific to the DMN. Hypoxia produced modest increases in activations in the visual attention network (VAN) during the motion detection task, and had no effect on activations in the visual cortex during visual stimulation. This regional specificity may be particularly pertinent to clinical populations characterized by hypoxemia and may enhance understanding of regional specificity in neurodegenerative disease pathology.
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Affiliation(s)
- Gabriella Mk Rossetti
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Giovanni d'Avossa
- Bangor Imaging Centre, School of Psychology, College of Human Sciences, Bangor University, Bangor, UK
| | - Matthew Rogan
- Bangor Imaging Centre, School of Psychology, College of Human Sciences, Bangor University, Bangor, UK
| | - Jamie H Macdonald
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Samuel J Oliver
- Extremes Research Group, School of Sport, Health and Exercise Sciences, College of Human Sciences, Bangor University, Bangor, UK
| | - Paul G Mullins
- Bangor Imaging Centre, School of Psychology, College of Human Sciences, Bangor University, Bangor, UK
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Sleight E, Stringer MS, Marshall I, Wardlaw JM, Thrippleton MJ. Cerebrovascular Reactivity Measurement Using Magnetic Resonance Imaging: A Systematic Review. Front Physiol 2021; 12:643468. [PMID: 33716793 PMCID: PMC7947694 DOI: 10.3389/fphys.2021.643468] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/01/2021] [Indexed: 12/27/2022] Open
Abstract
Cerebrovascular reactivity (CVR) magnetic resonance imaging (MRI) probes cerebral haemodynamic changes in response to a vasodilatory stimulus. CVR closely relates to the health of the vasculature and is therefore a key parameter for studying cerebrovascular diseases such as stroke, small vessel disease and dementias. MRI allows in vivo measurement of CVR but several different methods have been presented in the literature, differing in pulse sequence, hardware requirements, stimulus and image processing technique. We systematically reviewed publications measuring CVR using MRI up to June 2020, identifying 235 relevant papers. We summarised the acquisition methods, experimental parameters, hardware and CVR quantification approaches used, clinical populations investigated, and corresponding summary CVR measures. CVR was investigated in many pathologies such as steno-occlusive diseases, dementia and small vessel disease and is generally lower in patients than in healthy controls. Blood oxygen level dependent (BOLD) acquisitions with fixed inspired CO2 gas or end-tidal CO2 forcing stimulus are the most commonly used methods. General linear modelling of the MRI signal with end-tidal CO2 as the regressor is the most frequently used method to compute CVR. Our survey of CVR measurement approaches and applications will help researchers to identify good practice and provide objective information to inform the development of future consensus recommendations.
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Affiliation(s)
- Emilie Sleight
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Michael S. Stringer
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom,*Correspondence: Michael S. Stringer
| | - Ian Marshall
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Joanna M. Wardlaw
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Michael J. Thrippleton
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
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8
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Kim JH, Taylor AJ, Wang DJJ, Zou X, Ress D. Dynamics of the cerebral blood flow response to brief neural activity in human visual cortex. J Cereb Blood Flow Metab 2020; 40:1823-1837. [PMID: 31429358 PMCID: PMC7446561 DOI: 10.1177/0271678x19869034] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The blood oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI) signal depends on an interplay of cerebral blood flow (CBF), oxygen metabolism, and cerebral blood volume. Despite wide usage of BOLD fMRI, it is not clear how these physiological components create the BOLD signal. Here, baseline CBF and its dynamics evoked by a brief stimulus (2 s) in human visual cortex were measured at 3T. We found a stereotypical CBF response: immediate increase, rising to a peak a few second after the stimulus, followed by a significant undershoot. The BOLD hemodynamic response function (HRF) was also measured in the same session. Strong correlations between HRF and CBF peak responses indicate that the flow responses evoked by neural activation in nearby gray matter drive the early HRF. Remarkably, peak CBF and HRF were also strongly modulated by baseline perfusion. The CBF undershoot was reliable and significantly correlated with the HRF undershoot. However, late-time dynamics of the HRF and CBF suggest that oxygen metabolism can also contribute to the HRF undershoot. Combined measurement of the CBF and HRF for brief neural activation is a useful tool to understand the temporal dynamics of neurovascular and neurometabolic coupling.
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Affiliation(s)
- Jung Hwan Kim
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Amanda J Taylor
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Danny JJ Wang
- Laboratory of FMRI Technology (LOFT), Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, USA
| | - Xiaowei Zou
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - David Ress
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- David Ress, Baylor College of Medicine, 1 Baylor Plaza T115E, Houston, TX 77030, USA.
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9
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Netto JP, Iliff J, Stanimirovic D, Krohn KA, Hamilton B, Varallyay C, Gahramanov S, Daldrup-Link H, d'Esterre C, Zlokovic B, Sair H, Lee Y, Taheri S, Jain R, Panigrahy A, Reich DS, Drewes LR, Castillo M, Neuwelt EA. Neurovascular Unit: Basic and Clinical Imaging with Emphasis on Advantages of Ferumoxytol. Neurosurgery 2019; 82:770-780. [PMID: 28973554 DOI: 10.1093/neuros/nyx357] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 06/27/2017] [Indexed: 12/11/2022] Open
Abstract
Physiological and pathological processes that increase or decrease the central nervous system's need for nutrients and oxygen via changes in local blood supply act primarily at the level of the neurovascular unit (NVU). The NVU consists of endothelial cells, associated blood-brain barrier tight junctions, basal lamina, pericytes, and parenchymal cells, including astrocytes, neurons, and interneurons. Knowledge of the NVU is essential for interpretation of central nervous system physiology and pathology as revealed by conventional and advanced imaging techniques. This article reviews current strategies for interrogating the NVU, focusing on vascular permeability, blood volume, and functional imaging, as assessed by ferumoxytol an iron oxide nanoparticle.
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Affiliation(s)
- Joao Prola Netto
- Department of Neurology, Oregon Health & Science University, Portland, Oregon.,Department of Neuroradiology, Oregon Health & Science University, Portland, Oregon
| | - Jeffrey Iliff
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon
| | - Danica Stanimirovic
- Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada
| | - Kenneth A Krohn
- Department of Radiology, University of Washington, Seattle, Washington.,Department of Radiology, Oregon Health & Science University, Portland, Oregon
| | - Bronwyn Hamilton
- Department of Neuroradiology, Oregon Health & Science University, Portland, Oregon
| | - Csanad Varallyay
- Department of Neurology, Oregon Health & Science University, Portland, Oregon.,Department of Radiology, Oregon Health & Science University, Portland, Oregon
| | - Seymur Gahramanov
- Department of Neurosurgery, University of New Mexico, Albuquerque, New Mexico
| | | | - Christopher d'Esterre
- Department of Radiology, University of Calgary, Foothills Medical Center, Calgary, Alberta, Canada
| | - Berislav Zlokovic
- Zikha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Haris Sair
- Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland
| | - Yueh Lee
- Department of Radiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Saeid Taheri
- Department of Radiology and Radiological Sciences, Medical University of South Carolina, Charleston, South Carolina
| | - Rajan Jain
- Department of Radiology and Neurosurgery, New York University School of Medicine, New York, New York
| | - Ashok Panigrahy
- Department of Radiology, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania
| | - Daniel S Reich
- Translational Neuroradiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Lester R Drewes
- Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota
| | - Mauricio Castillo
- Department of Radiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Edward A Neuwelt
- Department of Neurology, Oregon Health & Science University, Portland, Oregon.,Department of Neurosurgery, Oregon Health & Science University, Portland, Oregon.,Portland Veterans Affairs Medical Center, Portland, Oregon
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10
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Hoiland RL, Fisher JA, Ainslie PN. Regulation of the Cerebral Circulation by Arterial Carbon Dioxide. Compr Physiol 2019; 9:1101-1154. [DOI: 10.1002/cphy.c180021] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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11
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Polyanskaya MV, Demushkina AA, Vasiliev IG, Gazdieva HS, Kholin AA, Zavadenko NN, Alikhanov AA. Role of contrast-free MR-perfusion in the diagnosis of potential epileptogenic foci in children with focal epilepsia. ACTA ACUST UNITED AC 2018. [DOI: 10.17749/2077-8333.2018.10.2.006-018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
ASL (Arterial Spin Labeling) – a novel modality of MR angiography – is based on radio-frequency labeling of aqueous protons in the arterial blood; the method is used to monitor blood supply to organs, including the brain. So far there has been little information on the use of ASL in children with focal epilepsy, especially in the pre-surgery period.Aim:to evaluate the perfusion patterns in seizure-free children with drug resistant focal epilepsy (FE) using the ASL mode of MRI.Materials and methods.We studied the ASL data of 54 (23-boys/31 girls) patients with FE treated in the Dpt. of Neurology at the Russian State Children Hospital from 2015 to 2018. The patients’ age varied from 4 months to 17 years. All images were produced with a 3T GE Discovery 750W system.Results. We found several brain perfusion patterns in children with FE; among other factors, those patterns depended on the clinical status of the patient, i. e. the interictal period or the early post- seizure period. The main pattern of the interictal period was characterized by a focal decrease in perfusion located around a structural focus identified on MRI scans. In the early post-seizure period, there was an increase in the arterial perfusion in the area of a structural epileptogenic lesion.Conclusion.ASL-MRI is an effective diagnostic method providing more information on children with FE during their pre-surgery phase. The ASL modality needs further research to rationalize its wider use as a preferred diagnostic tool or as a combination with the more complex PET and SPECT.
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12
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van Niftrik CHB, Piccirelli M, Bozinov O, Maldaner N, Strittmatter C, Pangalu A, Valavanis A, Regli L, Fierstra J. Impact of baseline CO 2 on Blood-Oxygenation-Level-Dependent MRI measurements of cerebrovascular reactivity and task-evoked signal activation. Magn Reson Imaging 2018; 49:123-130. [DOI: 10.1016/j.mri.2018.02.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/30/2018] [Accepted: 02/12/2018] [Indexed: 12/25/2022]
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13
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Angleys H, Jespersen SN, Østergaard L. The effects of capillary transit time heterogeneity on the BOLD signal. Hum Brain Mapp 2018; 39:2329-2352. [PMID: 29498762 DOI: 10.1002/hbm.23991] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 12/06/2017] [Accepted: 01/23/2018] [Indexed: 12/18/2022] Open
Abstract
Neurovascular coupling mechanisms give rise to vasodilation and functional hyperemia upon neural activation, thereby altering blood oxygenation. This blood oxygenation level dependent (BOLD) contrast allows studies of activation patterns in the working human brain by functional MRI (fMRI). The BOLD-weighted fMRI signal shows characteristic transients in relation to functional activation, such as the so-called initial dip, overshoot, and post-stimulus undershoot. These transients are modulated by other physiological stimuli and in disease, but the underlying physiological mechanisms remain incompletely understood. Capillary transit time heterogeneity (CTH) has been shown to affect oxygen extraction, and hence blood oxygenation. Here, we examine how recently reported redistributions of capillary blood flow during functional activation would be expected to affect BOLD signal transients. We developed a three-compartment (hemoglobin, plasma, and tissue) model to predict the BOLD signal, incorporating the effects of dynamic changes in CTH. Our model predicts that the BOLD signal represents the superposition of a positive component resulting from increases in cerebral blood flow (CBF), and a negative component, resulting from elevated tissue metabolism and homogenization of capillary flows (reduced CTH). The model reproduces salient features of BOLD signal dynamics under conditions such as hypercapnia, hyperoxia, and caffeine intake, where both brain physiology and BOLD characteristics are altered. Neuroglial signaling and metabolism could affect CBF and capillary flow patterns differently. Further studies of neurovascular and neuro-capillary coupling mechanisms may help us relate BOLD signals to the firing of certain neuronal populations based on their respective BOLD "fingerprints."
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Affiliation(s)
- Hugo Angleys
- Center of Functionally Integrative Neuroscience and MindLab, Aarhus University, Aarhus, Denmark
| | - Sune N Jespersen
- Center of Functionally Integrative Neuroscience and MindLab, Aarhus University, Aarhus, Denmark.,Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience and MindLab, Aarhus University, Aarhus, Denmark.,Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
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14
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Para AE, Sam K, Poublanc J, Fisher JA, Crawley AP, Mikulis DJ. Invalidation of fMRI experiments secondary to neurovascular uncoupling in patients with cerebrovascular disease. J Magn Reson Imaging 2017; 46:1448-1455. [PMID: 28152241 DOI: 10.1002/jmri.25639] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/03/2017] [Indexed: 12/29/2022] Open
Abstract
PURPOSE Blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is a technique used to infer neuronal activity from the observed changes in blood flow. Cerebrovascular reactivity (CVR) is the ability of arterioles to increase blood flow in response to vasodilatory stimulus. We hypothesize that in areas of disease where there is exhausted vascular reserve and impaired CVR there will be diminished blood flow response following neuronal activation, and that these areas would appear as false-negative tests on BOLD fMRI. MATERIALS AND METHODS Patients with steno-occlusive disease and unilateral hemodynamic impairment received a standardized hypercapnic stimuli while being imaged with BOLD fMRI to generate CVR maps. These were compared to traditional BOLD fMRI maps of neuronal activation in the motor cortex in response to a motor task. RESULTS Neuronal activation from the motor task was found to be linearly correlated with CVR (n = 11 patients, R = 0.82). Regions with positive (normal) CVR showed positive activation on BOLD fMRI, while regions with negative CVR had attenuated neuronal activation on BOLD fMRI. CONCLUSION In areas with cerebrovascular disease where CVR is impaired, there is uncoupling of neuronal activation and blood flow that confounds traditional BOLD fMRI. CVR mapping is a noninvasive MRI-based imaging technique that can provide information about the vascular reactivity of the brain that is important to consider when interpreting traditional BOLD fMRI studies. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1448-1455.
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Affiliation(s)
- Andrea E Para
- Department of Medical Imaging, University of Western Ontario, London, Canada.,Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, Canada
| | - Kevin Sam
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, Canada
| | - Julien Poublanc
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, Canada
| | - Joseph A Fisher
- Department of Anesthesiology, University Health Network and University of Toronto, Toronto, Canada
| | - Adrian P Crawley
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, Canada.,Department of Medical Imaging, University of Toronto, Toronto, Canada
| | - David J Mikulis
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, Canada.,Department of Medical Imaging, University of Toronto, Toronto, Canada
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15
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Warnert EA, Rodrigues JC, Burchell AE, Neumann S, Ratcliffe LE, Manghat NE, Harris AD, Adams Z, Nightingale AK, Wise RG, Paton JF, Hart EC. Is High Blood Pressure Self-Protection for the Brain? Circ Res 2016; 119:e140-e151. [DOI: 10.1161/circresaha.116.309493] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/22/2016] [Accepted: 09/26/2016] [Indexed: 12/19/2022]
Abstract
Rationale:
Data from animal models of hypertension indicate that high blood pressure may develop as a vital mechanism to maintain adequate blood flow to the brain. We propose that congenital vascular variants of the posterior cerebral circulation and cerebral hypoperfusion could partially explain the pathogenesis of essential hypertension, which remains enigmatic in 95% of patients.
Objective:
To evaluate the role of the cerebral circulation in the pathophysiology of hypertension.
Methods and Results:
We completed a series of retrospective and mechanistic case-control magnetic resonance imaging and physiological studies in normotensive and hypertensive humans (n=259). Interestingly, in humans with hypertension, we report a higher prevalence of congenital cerebrovascular variants; vertebral artery hypoplasia, and an incomplete posterior circle of Willis, which were coupled with increased cerebral vascular resistance, reduced cerebral blood flow, and a higher incidence of lacunar type infarcts. Causally, cerebral vascular resistance was elevated before the onset of hypertension and elevated sympathetic nerve activity (n=126). Interestingly, untreated hypertensive patients (n=20) had a cerebral blood flow similar to age-matched controls (n=28). However, participants receiving antihypertensive therapy (with blood pressure controlled below target levels) had reduced cerebral perfusion (n=19). Finally, elevated cerebral vascular resistance was a predictor of hypertension, suggesting that it may be a novel prognostic or diagnostic marker (n=126).
Conclusions:
Our data indicate that congenital cerebrovascular variants in the posterior circulation and the associated cerebral hypoperfusion may be a factor in triggering hypertension. Therefore, lowering blood pressure may worsen cerebral perfusion in susceptible individuals.
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Affiliation(s)
- Esther A.H. Warnert
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Jonathan C.L. Rodrigues
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Amy E. Burchell
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Sandra Neumann
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Laura E.K. Ratcliffe
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Nathan E. Manghat
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Ashley D. Harris
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Zoe Adams
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Angus K. Nightingale
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Richard G. Wise
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Julian F.R. Paton
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
| | - Emma C. Hart
- From the Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom (E.A.H.W., R.G.W.); CardioNomics Research Group, Clinical Research and Imaging Centre (J.C.L.R., A.E.B., S.N., L.E.K.R., N.E.M., A.K.N., J.F.R.P., E.C.H.) and School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences (J.C.L.R., S.N., L.E.K.R., Z.A., J.F.R.P., E.C.H.), University of Bristol, United Kingdom; University Hospitals Bristol NHS Foundation Trust, United
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16
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Wu J, Dehkharghani S, Nahab F, Qiu D. Acetazolamide-augmented dynamic BOLD (aczBOLD) imaging for assessing cerebrovascular reactivity in chronic steno-occlusive disease of the anterior circulation: An initial experience. NEUROIMAGE-CLINICAL 2016; 13:116-122. [PMID: 27942454 PMCID: PMC5137181 DOI: 10.1016/j.nicl.2016.11.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/15/2016] [Accepted: 11/16/2016] [Indexed: 01/22/2023]
Abstract
The purpose of this study was to measure cerebrovascular reactivity (CVR) in chronic steno-occlusive disease using a novel approach that couples BOLD imaging with acetazolamide (ACZ) vasoreactivity (aczBOLD), to evaluate dynamic effects of ACZ on BOLD and to establish the relationship between aczBOLD and dynamic susceptibility contrast (DSC) perfusion MRI. Eighteen patients with unilateral chronic steno-occlusive disease of the anterior circulation underwent a 20-min aczBOLD imaging protocol, with ACZ infusion starting at 5 min of scan initiation. AczBOLD reactivity was calculated on a voxel-by-voxel basis to generate CVR maps for subsequent quantitative analyses. Reduced CVR was observed in the diseased vs. the normal hemisphere both by qualitative and quantitative assessment (gray matter (GM): 4.13% ± 1.16% vs. 4.90% ± 0.98%, P = 0.002; white matter (WM): 2.83% ± 1.23% vs. 3.50% ± 0.94%, P = 0.005). In all cases BOLD signal began increasing immediately following ACZ infusion, approaching a plateau at ~ 8.5 min after infusion, with the tissue volume of reduced augmentation increasing progressively with time, peaking at 2.60 min (time range above 95% of the maximum value: 0–4.43 min) for the GM and 1.80 min (time range above 95% of the maximum value: 1.40–3.53 min) for the WM. In the diseased hemisphere, aczBOLD CVR significantly correlated with baseline DSC time-to-maximum of the residue function (Tmax) (P = 0.008 for the WM) and normalized cerebral blood flow (P = 0.003 for the GM, and P = 0.001 for the WM). AczBOLD provides a novel, safe, easily implementable approach to CVR measurement in the routine clinical environments. Further studies can establish quantitative thresholds from aczBOLD towards identification of patients at heightened risk of recurrent ischemia and cognitive decline. A method coupling BOLD with ACZ challenge (aczBOLD) for CVR assessment was proposed. Compromised CVR was detected in patients with cerebrovascular disease. Dynamic effects of ACZ on BOLD were characterized. CVR correlated with baseline dynamic susceptibility contrast perfusion MRI.
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Affiliation(s)
- Junjie Wu
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Seena Dehkharghani
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA 30322, United States; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Fadi Nahab
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Deqiang Qiu
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA 30322, United States
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17
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Wu J, Dehkharghani S, Nahab F, Allen J, Qiu D. The Effects of Acetazolamide on the Evaluation of Cerebral Hemodynamics and Functional Connectivity Using Blood Oxygen Level-Dependent MR Imaging in Patients with Chronic Steno-Occlusive Disease of the Anterior Circulation. AJNR Am J Neuroradiol 2016; 38:139-145. [PMID: 27758776 DOI: 10.3174/ajnr.a4973] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 08/20/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Measuring cerebrovascular reactivity with the use of vasodilatory stimuli, such as acetazolamide, is useful for chronic cerebrovascular steno-occlusive disease. The purpose of this study was to evaluate the effects of acetazolamide on the assessment of hemodynamic impairment and functional connectivity by using noninvasive resting-state blood oxygen level-dependent MR imaging. MATERIALS AND METHODS A 20-minute resting-state blood oxygen level-dependent MR imaging scan was acquired with infusion of acetazolamide starting at 5 minutes after scan initiation. A recently developed temporal-shift analysis technique was applied on blood oxygen level-dependent MR imaging data before and after acetazolamide infusion to identify regions with hemodynamic impairment, and the results were compared by using contrast agent-based DSC perfusion imaging as the reference standard. Functional connectivity was compared with and without correction on the signal by using information from temporal-shift analysis, before and after acetazolamide infusion. RESULTS Visually, temporal-shift analysis of blood oxygen level-dependent MR imaging data identified regions with compromised hemodynamics as defined by DSC, though performance deteriorated in patients with bilateral disease. The Dice similarity coefficient between temporal-shift and DSC maps was higher before (0.487 ± 0.150 by using the superior sagittal sinus signal as a reference for temporal-shift analysis) compared with after acetazolamide administration (0.384 ± 0.107) (P = .006, repeated-measures ANOVA). Functional connectivity analysis with temporal-shift correction identified brain network nodes that were otherwise missed. The accuracy of functional connectivity assessment decreased after acetazolamide administration (P = .015 for default mode network, repeated-measures ANOVA). CONCLUSIONS Temporal-shift analysis of blood oxygen level-dependent MR imaging can identify brain regions with hemodynamic compromise in relation to DSC among patients with chronic cerebrovascular disease. The use of acetazolamide reduces the accuracy of temporal-shift analysis and network connectivity evaluation.
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Affiliation(s)
- J Wu
- From the Departments of Radiology and Imaging Sciences (J.W., S.D., J.A., D.Q.)
| | - S Dehkharghani
- From the Departments of Radiology and Imaging Sciences (J.W., S.D., J.A., D.Q.)
| | - F Nahab
- Neurology (F.N.), Emory University School of Medicine, Atlanta, Georgia
| | - J Allen
- From the Departments of Radiology and Imaging Sciences (J.W., S.D., J.A., D.Q.)
| | - D Qiu
- From the Departments of Radiology and Imaging Sciences (J.W., S.D., J.A., D.Q.)
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18
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Dieleman N, van der Kolk AG, Zwanenburg JJM, Brundel M, Harteveld AA, Biessels GJ, Visser F, Luijten PR, Hendrikse J. Relations between location and type of intracranial atherosclerosis and parenchymal damage. J Cereb Blood Flow Metab 2016; 36:1271-80. [PMID: 26661234 PMCID: PMC4929701 DOI: 10.1177/0271678x15616401] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 09/21/2015] [Accepted: 09/28/2015] [Indexed: 02/02/2023]
Abstract
The aim of this study was to assess the relation between location and type of intracranial atherosclerosis (ICAS) and cortical microinfarcts (CMIs) and macroinfarcts in 18 patients presenting with ischemic stroke (n = 12) or transient ischemic attack (TIA) (n = 6) using 7 tesla MR imaging. The protocol included: 3D T2-weighted FLAIR and 3D T1-weighted Magnetization-Preparation Inversion Recovery Turbo Spin Echo sequence. ICAS lesions and infarcts were scored by two raters. The relation between ICAS lesions, calculated ratios of ICAS lesion characteristics, location, and infarcts were examined using linear regression analyses. A total number of 75 ICAS lesions (all patients), 101 CMIs (78% of patients), and 31 macroinfarcts (67% of patients) were found. Seventy-six and sixty-five percent of the CMIs and macroinfarcts, respectively, were found in the same vascular territory as the ICAS lesions (p = 0.977, p = 0.167, respectively). A positive correlation existed between the number of macroinfarcts and CMIs (p < 0.05). In patients with macroinfarcts, we found more concentric (p < 0.01) and diffuse (p < 0.05) type of ICAS lesions. A high prevalence of brain tissue lesions, both macroinfarcts and CMIs, were found in patients with ICAS. Macroinfarcts were found to be related to specific ICAS lesion types. The type of ICAS lesion seems to be promising as a marker for ICAS patients at higher risk of future infarcts.
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Affiliation(s)
- Nikki Dieleman
- Department of Radiology, University Medical Center Utrecht, the Netherlands
| | | | - Jaco J M Zwanenburg
- Department of Radiology, University Medical Center Utrecht, the Netherlands Image Sciences Institute, University Medical Center Utrecht, the Netherlands
| | - Manon Brundel
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, the Netherlands
| | - Anita A Harteveld
- Department of Radiology, University Medical Center Utrecht, the Netherlands
| | - Geert J Biessels
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, the Netherlands
| | - Fredy Visser
- Department of Radiology, University Medical Center Utrecht, the Netherlands Philips Healthcare, Best, the Netherlands
| | - Peter R Luijten
- Department of Radiology, University Medical Center Utrecht, the Netherlands
| | - Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, the Netherlands
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19
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Xu J, Chen A, Xiao J, Jiang Z, Tian Y, Tang Q, Cao P, Dai Y, Krainik A, Shen J. Evaluation of tumour vascular distribution and function using immunohistochemistry and BOLD fMRI with carbogen inhalation. Clin Radiol 2016; 71:1255-1262. [PMID: 27170218 DOI: 10.1016/j.crad.2016.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 02/18/2016] [Accepted: 04/06/2016] [Indexed: 10/21/2022]
Abstract
AIM To evaluate oxygenation changes in rat subcutaneous C6 gliomas using blood-oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI) combined with non-haemodynamic response function (non-HRF) analysis. MATERIALS AND METHODS BOLD fMRI were performed during carbogen inhalation in 20 Wistar rats bearing gliomas. Statistical maps of spatial oxygenation changes were computed by a dedicated non-HRF analysis algorithm. Three types of regions of interest (ROIs) were defined: (1) maximum re-oxygenation zone (ROImax), (2) re-oxygenation zones that were less than the maximum re-oxygenation (ROInon-max), and (3) zones without significant re-oxygenation (ROInone). The values of percent BOLD signal change (PSC), percent enhancement (ΔSI), and significant re-oxygenation (T) were extracted from each ROI. Tumours were sectioned for histology using the fMRI scan orientation and were stained with haematoxylin and eosin and CD105. The number of microvessels (MVN) in each ROI was counted. Differences and correlations among the values for T, PSC, ΔSI, and MVN were determined. RESULTS After carbogen inhalation, the PSC significantly increased in the ROImax areas (p<0.01) located in the tumour parenchyma. No changes occurred in any of the ROInone areas (20/20). Some changes occurred in a minority of the ROInon-max areas (3/60) corresponding to tumour necrosis. MVN and PSC (R=0.59, p=0.01) were significantly correlated in the ROImax areas. In the ROInon-max areas, MVN was significantly correlated with PSC (R=0.55, p=0.00) and ΔSI (R=0.37, p=0.00). CONCLUSIONS Statistical maps obtained via BOLD fMRI with non-HRF analysis can assess the re-oxygenation of gliomas.
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Affiliation(s)
- J Xu
- Department of Radiology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - A Chen
- Department of Radiology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - J Xiao
- Department of Radiology, The Central Hospital of Wuhan, Wuhan, China
| | - Z Jiang
- Department of Radiology, The Second Affiliated Hospital of Soochow University, Suzhou, China; Institute of Radiotherapy & Oncology, Soochow University, Suzhou, China.
| | - Y Tian
- Institute of Radiotherapy & Oncology, Soochow University, Suzhou, China; Suzhou Key Laboratory for Radiation Oncology, Suzhou, China
| | - Q Tang
- Department of Radiology, Wuxi People's Hospital, Wuxi, China
| | - P Cao
- Department of Radiology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Y Dai
- Magnetic Resonance Imaging Institute for Biomedical Research, Wayne State University, Detroit, MI, USA
| | - A Krainik
- Department of Neuroradiology and MRI, CHU Grenoble-IFR1, Grenoble, France
| | - J Shen
- Department of Radiology, The Second Affiliated Hospital of Soochow University, Suzhou, China
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20
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Ladner TR, Donahue MJ, Arteaga DF, Faraco CC, Roach BA, Davis LT, Jordan LC, Froehler MT, Strother MK. Prior Infarcts, Reactivity, and Angiography in Moyamoya Disease (PIRAMD): a scoring system for moyamoya severity based on multimodal hemodynamic imaging. J Neurosurg 2016; 126:495-503. [PMID: 26967789 DOI: 10.3171/2015.11.jns15562] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Quantification of the severity of vasculopathy and its impact on parenchymal hemodynamics is a necessary prerequisite for informing management decisions and evaluating intervention response in patients with moyamoya. The authors performed digital subtraction angiography and noninvasive structural and hemodynamic MRI, and they outline a new classification system for patients with moyamoya that they have named Prior Infarcts, Reactivity, and Angiography in Moyamoya Disease (PIRAMD). METHODS Healthy control volunteers (n = 11; age 46 ± 12 years [mean ± SD]) and patients (n = 25; 42 ± 13.5 years) with angiographically confirmed moyamoya provided informed consent and underwent structural (T1-weighted, T2-weighted, FLAIR, MR angiography) and hemodynamic (T2*- and cerebral blood flow-weighted) 3-T MRI. Cerebrovascular reactivity (CVR) in the internal carotid artery territory was assessed using susceptibility-weighted MRI during a hypercapnic stimulus. Only hemispheres without prior revascularization were assessed. Each hemisphere was considered symptomatic if localizing signs were present on neurological examination and/or there was a history of transient ischemic attack with symptoms referable to that hemisphere. The PIRAMD factor weighting versus symptomatology was optimized using binary logistic regression and receiver operating characteristic curve analysis with bootstrapping. The PIRAMD finding was scored from 0 to 10. For each hemisphere, 1 point was assigned for prior infarct, 3 points for reduced CVR, 3 points for a modified Suzuki Score ≥ Grade II, and 3 points for flow impairment in ≥ 2 of 7 predefined vascular territories. Hemispheres were divided into 3 severity grades based on total PIRAMD score, as follows: Grade 1, 0-5 points; Grade 2, 6-9 points; and Grade 3, 10 points. RESULTS In 28 of 46 (60.9%) hemispheres the findings met clinical symptomatic criteria. With decreased CVR, the odds ratio of having a symptomatic hemisphere was 13 (95% CI 1.1-22.6, p = 0.002). The area under the curve for individual PIRAMD factors was 0.67-0.72, and for the PIRAMD grade it was 0.845. There were 0/8 (0%), 10/18 (55.6%), and 18/20 (90%) symptomatic PIRAMD Grade 1, 2, and 3 hemispheres, respectively. CONCLUSIONS A scoring system for total impairment is proposed that uses noninvasive MRI parameters. This scoring system correlates with symptomatology and may provide a measure of hemodynamic severity in moyamoya, which could be used for guiding management decisions and evaluating intervention response.
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Affiliation(s)
| | | | | | | | | | | | - Lori C Jordan
- Division of Pediatric Neurology, Department of Pediatrics; and
| | - Michael T Froehler
- Departments of Neurology and Neurosurgery, Vanderbilt University Medical Center, Nashville, Tennessee
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21
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The cumulative influence of hyperoxia and hypercapnia on blood oxygenation and R*₂. J Cereb Blood Flow Metab 2015; 35:2032-42. [PMID: 26174329 PMCID: PMC4671125 DOI: 10.1038/jcbfm.2015.168] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 06/09/2015] [Accepted: 06/11/2015] [Indexed: 01/01/2023]
Abstract
Cerebrovascular reactivity (CVR)-weighted blood-oxygenation-level-dependent magnetic resonance imaging (BOLD-MRI) experiments are frequently used in conjunction with hyperoxia. Owing to complex interactions between hyperoxia and hypercapnia, quantitative effects of these gas mixtures on BOLD responses, blood and tissue R2*, and blood oxygenation are incompletely understood. Here we performed BOLD imaging (3 T; TE/TR=35/2,000 ms; spatial resolution=3 × 3 × 3.5 mm(3)) in healthy volunteers (n=12; age=29±4.1 years) breathing (i) room air (RA), (ii) normocapnic-hyperoxia (95% O2/5% N2, HO), (iii) hypercapnic-normoxia (5% CO2/21% O2/74% N2, HC-NO), and (iv) hypercapnic-hyperoxia (5% CO2/95% O2, HC-HO). For HC-HO, experiments were performed with separate RA and HO baselines to control for changes in O2. T2-relaxation-under-spin-tagging MRI was used to calculate basal venous oxygenation. Signal changes were quantified and established hemodynamic models were applied to quantify vasoactive blood oxygenation, blood-water R2*, and tissue-water R2*. In the cortex, fractional BOLD changes (stimulus/baseline) were HO/RA=0.011±0.007; HC-NO/RA=0.014±0.004; HC-HO/HO=0.020±0.008; and HC-HO/RA=0.035±0.010; for the measured basal venous oxygenation level of 0.632, this led to venous blood oxygenation levels of 0.660 (HO), 0.665 (HC-NO), and 0.712 (HC-HO). Interleaving a HC-HO stimulus with HO baseline provided a smaller but significantly elevated BOLD response compared with a HC-NO stimulus. Results provide an outline for how blood oxygenation differs for several gas stimuli and provides quantitative information on how hypercapnic BOLD CVR and R2* are altered during hyperoxia.
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22
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Biessels GJ. Diagnosis and treatment of vascular damage in dementia. Biochim Biophys Acta Mol Basis Dis 2015; 1862:869-77. [PMID: 26612719 DOI: 10.1016/j.bbadis.2015.11.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 01/04/2023]
Abstract
This paper provides an overview of cognitive impairment due to vascular brain damage, which is referred to as vascular cognitive impairment (VCI). Over the past decades, we have seen marked progress in detecting VCI, both through maturation of diagnostic concepts and through advances in brain imaging, especially MRI. Yet in daily practice, it is often challenging to establish the diagnosis, particularly in patients where there is no evident temporal relation between a cerebrovascular event and cognitive dysfunction. Because vascular damage is such a common cause of cognitive dysfunction, it provides an obvious target for treatment. In patients whose cognitive dysfunction follows directly after a stroke, the etiological classification of this stroke will direct treatment. In many patients however, VCI develops due to so-called "silent vascular damage," without evident cerebrovascular events. In these patients, small vessel diseases (SVDs) are the most common cause. Yet no SVD-specific treatments currently exist, which is due to incomplete understanding of the pathophysiology. This review addresses developments in this field. It offers a framework to translate diagnostic criteria to daily practice, addresses treatment, and highlights some future perspectives. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia, edited by M. Paul Murphy, Roderick A. Corriveau, and Donna M. Wilcock.
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Affiliation(s)
- Geert Jan Biessels
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center, Utrecht, The Netherlands.
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23
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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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24
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Examining the regional and cerebral depth-dependent BOLD cerebrovascular reactivity response at 7 T. Neuroimage 2015; 114:239-48. [DOI: 10.1016/j.neuroimage.2015.04.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 03/06/2015] [Accepted: 04/07/2015] [Indexed: 01/04/2023] Open
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25
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Peng SL, Su P, Wang FN, Cao Y, Zhang R, Lu H, Liu P. Optimization of phase-contrast MRI for the quantification of whole-brain cerebral blood flow. J Magn Reson Imaging 2015; 42:1126-33. [PMID: 25676350 DOI: 10.1002/jmri.24866] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/22/2015] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Whole-brain cerebral blood flow (CBF) measured by phase-contrast MRI (PC-MRI) provides an important index for brain function. This work aimed to optimize the PC-MRI imaging protocol for accurate CBF measurements. METHODS Two studies were performed on a 3 Tesla system. In Study 1 (N = 12), we optimized in-plane resolution of PC-MRI acquisition for CBF quantification by considering accuracy, precision, and scan duration. In Study 2 (N = 7), we assessed the detrimental effect of nonperpendicular imaging slice orientation on CBF quantification. Both One-way analysis of variance with repeated measurement and Friedman test were used to examine the effects of resolution and angulation on CBF quantification. Additionally, we evaluated the inter-rater reliability in PC-MRI data processing. RESULTS Our results showed that CBF measurement with 0.7 mm resolution could be overestimated by up to 13.3% when compared with 0.4 mm resolution. Moreover, CBF could also be overestimated by up to 18.8% when the slice orientation is deviated by 30° from the ideal angulation. However, within 10° of the ideal slice orientation, estimated CBF was not significantly different from each other (P = 0.23 and 0.45 for internal carotid artery and vertebral artery, respectively). Inter-rater difference was <3%. CONCLUSION For fast and accurate quantification of whole-brain CBF with PC-MRI, we recommend the use of an imaging resolution of 0.5 mm and a slice orientation that is less than 10° from vessel's axial plane.
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Affiliation(s)
- Shin-Lei Peng
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA.,Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Pan Su
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA.,Biomedical Engineering Graduate Program, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Fu-Nien Wang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Yan Cao
- Department of Mathematical Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Rong Zhang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
| | - Hanzhang Lu
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA.,Biomedical Engineering Graduate Program, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Peiying Liu
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
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