Temporal and Spatial Variances in Arterial Spin-Labeling Are Inversely Related to Large-Artery Blood Velocity

Robertson, Andrew D.; Matta, Gildo; Basile, Vincenzo S.; Black, Sandra E.; Macgowan, Christopher K.; Detre, John A.; MacIntosh, Bradley J.

doi:10.3174/ajnr.a5257

Cited by 20 publications

(24 citation statements)

References 36 publications

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“…That study did not measure arterial diameter, so a change in blood flow despite no change in velocity cannot be ruled out. The lack of a change in velocity, however, is consistent with our finding of no change in sCoV, given the relationship between sCoV, blood flow velocity and arterial transit time (Mutsaerts et al, 2017 ; Robertson et al, 2017 ). Spatial CoV of ASL with a single post-label delay is a heuristic index of arterial transit time (Mutsaerts et al, 2017 ), whereby a prolonged transit time leads to greater spatial variation of intensities within the CBF image.…”

Section: Discussionsupporting

confidence: 90%

Exercise Training Increases Parietal Lobe Cerebral Blood Flow in Chronic Stroke: An Observational Study

Robertson

Marzolini

Middleton

et al. 2017

Front. Aging Neurosci.

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Exercise is increasingly recommended as an essential component of stroke rehabilitation, yet uncertainty remains with respect to its direct effect on the cerebral vasculature. The current study first demonstrated the repeatability of pseudo-continuous arterial spin labeling (ASL) magnetic resonance imaging (MRI) in older adults with stroke, and then investigated the change in cerebrovascular function following a 6-month cardiovascular rehabilitation program. In the repeatability study, 12 participants at least 3 months post-stroke underwent two ASL imaging scans 1 month apart. In the prospective observational study, eight individuals underwent ASL imaging and aerobic fitness testing before and after a 6-month cardiovascular rehabilitation program. Cerebral blood flow (CBF) and the spatial coefficient of variation of CBF (sCoV) were quantified to characterize tissue-level perfusion and large cerebral artery transit time properties, respectively. In repeat scanning, intraclass correlation (ICC) indicated moderate test-retest reliability for global gray matter CBF (ICC = 0.73) and excellent reliability for sCoV (ICC = 0.94). In the observational study, gray matter CBF increased after training (baseline: 40 ± 13 vs. 6-month: 46 ± 12 ml·100 g−1·min−1, P = 0.036). The greatest change occurred in the parietal lobe (+18 ± 12%). Gray matter sCoV, however, did not change following training (P = 0.31). This study provides preliminary evidence that exercise-based rehabilitation in chronic stroke enhances tissue-level perfusion, without changing the relative hemodynamic properties of the large cerebral arteries.

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Section: Discussionsupporting

confidence: 90%

Exercise Training Increases Parietal Lobe Cerebral Blood Flow in Chronic Stroke: An Observational Study

Robertson

Marzolini

Middleton

et al. 2017

Front. Aging Neurosci.

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“…Our results suggest that cerebral hemodynamic alterations represent a useful element in assessing AD profiles, independent of structural, amyloid burden, or glucose uptake abnormalities. A recent study found that extracranial blood velocity is inversely related to ASL sCoV; which unfortunately was not possible to evaluate in the current study because phase contrast angiography from external arteries was not collected. Future studies are required to disambiguate large‐artery from small‐vessel hemodynamic influences on the ASL sCoV metric.…”

Section: Discussionmentioning

confidence: 82%

Classifying cognitive impairment based on the spatial heterogeneity of cerebral blood flow images

Shirzadi

Stefanović

Mutsaerts

et al. 2019

Magnetic Resonance Imaging

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Background The spatial coefficient of variation (sCoV) of arterial spin‐labeled (ASL) MRI can index cerebral blood flow spatial heterogeneity. This metric reflects delayed blood delivery—seen as a hyperintense ASL signal juxtaposed by hypointense regions. Purpose To investigate the use of ASL‐sCoV in the classification of cognitively unimpaired (CU), mild cognitive impairment (MCI), and Alzheimer's disease (AD) cohorts. Study Type Prospective/cohort. Population Baseline ASL images from AD neuroimaging initiative dataset in three groups of CU, MCI, and AD (N = 258). Field Strength/Sequence Pulsed ASL (PICORE QT2) images were acquired on 3 T Siemens systems (TE/TR = 12/3400 msec, TI1/2 = 700/1900 msec). Assessment ASL‐sCoV was calculated in temporal, parietal, occipital, and frontal lobes as well as whole gray matter. Statistical Tests The primary analysis used an analysis of covariance to investigate sCoV and cognitive group (CU, MCI, AD) associations. We also evaluated the repeatability of sCoV by calculating within‐subject agreement in a subgroup of CU participants with a repeat ASL. The secondary analyses assessed ventricular volume, amyloid burden, glucose uptake, ASL‐sCoV, and regional CBF as cognitive group classifiers using logistic regression models and receiver operating characteristic analyses. Results We found that global and temporal lobe sCoV differed between cognitive groups (P = 0.006). Post‐hoc tests showed that temporal lobe sCoV was lower in CU than in MCI (Cohen's d = –0.36) or AD (Cohen's d = –1.36). We found that sCoV was moderately repeatable in CU (intersession intraclass correlation = 0.50; intrasession intraclass correlation = 0.88). Subsequent logistic regression analyses revealed that temporal lobe sCoV and amyloid uptake classified CU vs. MCI (P < 0.01; accuracy = 78%). Temporal lobe sCoV, amyloid, and glucose uptake classified CU vs. AD (P < 0.01; accuracy = 97%); glucose uptake significantly classified MCI vs. AD (P < 0.01; accuracy = 85%). Data Conclusion We showed that ASL spatial heterogeneity can be used alongside AD neuroimaging markers to distinguish cognitive groups, in particular, cognitively unimpaired from cognitively impaired individuals. Level of Evidence: 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;50:858–867.

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“…the spatial coefficient of variation (CoV) of CBF images) as a region-of-interest (ROI)-based surrogate measure for prolonged ATT. 27,28 A study of subjects with hypertension showed that spatial CoV, which is calculated from the standard deviation in an ROI divided by the ROI mean in single-PLD pCASL images, is strongly correlated with ATT measured by flow encoding arterial spin tagging (FEAST). 27 Another study of healthy adults and patients with cerebrovascular disease reported that spatial CoV from single-PLD pCASL images is inversely correlated with extracranial arterial blood velocity measured by phase-contrast MR imaging.…”

Section: Introductionmentioning

confidence: 99%

Spatial coefficient of variation in pseudo-continuous arterial spin labeling cerebral blood flow images as a hemodynamic measure for cerebrovascular steno-occlusive disease: A comparative ¹⁵O positron emission tomography study

Ibaraki

Nakamura

Toyoshima

et al. 2018

J Cereb Blood Flow Metab

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Pseudo-continuous arterial spin labeling (pCASL) is a completely non-invasive method of cerebral perfusion measurement. However, cerebral blood flow (CBF) quantification is hampered by arterial transit artifacts characterized by bright vascular signals surrounded by decreased signals in tissue regions, which commonly appear in patients with reduced cerebral perfusion pressure. The spatial coefficient of variation (CoV) of pCASL CBF images has been proposed as an alternative region-of-interest (ROI)-based hemodynamic measure to predict prolonged arterial transit time (ATT). This retrospective study investigates the utility of spatial CoV by comparison with O positron emission tomography (PET). For patients with cerebrovascular steno-occlusive disease ( n = 17), spatial CoV was positively correlated with ATT independently measured by pulsed arterial spin labeling ( r = 0.597, p< 0.001), confirming its role as an ATT-like hemodynamic measure. Comparisons with O PET demonstrated that spatial CoV was positively correlated with vascular mean transit time ( r = 0.587, p< 0.001) and negatively correlated with both resting CBF ( r = -0.541, p = 0.001) and CBF response to hypercapnia ( r = -0.373, p = 0.030). ROI-based spatial CoV calculated from single time-point pCASL can potentially detect subtle perfusion abnormalities in clinical settings.

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Temporal and Spatial Variances in Arterial Spin-Labeling Are Inversely Related to Large-Artery Blood Velocity

Cited by 20 publications

References 36 publications

Exercise Training Increases Parietal Lobe Cerebral Blood Flow in Chronic Stroke: An Observational Study

Exercise Training Increases Parietal Lobe Cerebral Blood Flow in Chronic Stroke: An Observational Study

Classifying cognitive impairment based on the spatial heterogeneity of cerebral blood flow images

Spatial coefficient of variation in pseudo-continuous arterial spin labeling cerebral blood flow images as a hemodynamic measure for cerebrovascular steno-occlusive disease: A comparative ¹⁵O positron emission tomography study

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Temporal and Spatial Variances in Arterial Spin-Labeling Are Inversely Related to Large-Artery Blood Velocity

Cited by 20 publications

References 36 publications

Exercise Training Increases Parietal Lobe Cerebral Blood Flow in Chronic Stroke: An Observational Study

Exercise Training Increases Parietal Lobe Cerebral Blood Flow in Chronic Stroke: An Observational Study

Classifying cognitive impairment based on the spatial heterogeneity of cerebral blood flow images

Spatial coefficient of variation in pseudo-continuous arterial spin labeling cerebral blood flow images as a hemodynamic measure for cerebrovascular steno-occlusive disease: A comparative 15O positron emission tomography study

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Spatial coefficient of variation in pseudo-continuous arterial spin labeling cerebral blood flow images as a hemodynamic measure for cerebrovascular steno-occlusive disease: A comparative ¹⁵O positron emission tomography study