Quantitative Blood Flow Measurements in Gliomas Using Arterial Spin-Labeling at 3T: Intermodality Agreement and Inter- and Intraobserver Reproducibility Study

The accuracy of cerebral blood flow measurements using pseudo-continuous arterial spin labeling can be affected by vascular factors other than cerebral blood flow, such as flow velocity and arterial transit time. We aimed to elucidate the effects of common variations in vascular anatomy of the circle of Willis on pseudo-continuous arterial spin labeling signal. In addition, we investigated whether possible differences in pseudo-continuous arterial spin labeling signal could be mediated by differences in flow velocities. Two hundred and three elderly participants underwent magnetic resonance angiography of the circle of Willis and pseudo-continuous arterial spin labeling scans. Mean pseudo-continuous arterial spin labeling-cerebral blood flow signal was calculated for the gray matter of the main cerebral flow territories. Mean cerebellar gray matter pseudo-continuous arterial spin labeling-cerebral blood flow was significantly lower in subjects having a posterior fetal circle of Willis variant with an absent P1 segment. The posterior fetal circle of Willis variants also showed a significantly higher pseudo-continuous arterial spin labeling-cerebral blood flow signal in the ipsilateral flow territory of the posterior cerebral artery. Flow velocity in the basilar artery was significantly lower in these posterior fetal circle of Willis variants. This study indicates that pseudo-continuous arterial spin labeling measurements underestimate cerebral blood flow in the posterior flow territories and cerebellum of subjects with a highly prevalent variation in circle of Willis morphology. Additionally, our data suggest that this effect is mediated by concomitant differences in flow velocity between the supplying arteries.

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Pseudo-asymmetry of cerebral blood flow in arterial spin labeling caused by unilateral fetal-type circle of Willis: Technical limitation or a way to better understanding physiological variations of cerebral perfusion and improving arterial spin labeling acquisition?

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x16653614 ◽

2016 ◽

Vol 36 (9) ◽

pp. 1641-1643 ◽

Cited By ~ 2

Author(s):

B Law-ye ◽

B Geerts ◽

D Galanaud ◽

D Dormont ◽

N Pyatigorskaya

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Arterial Spin Labeling ◽

Spin Labeling ◽

Circle Of Willis ◽

Flow Measurements ◽

Technical Limitation ◽

Continuous Arterial Spin Labeling ◽

Blood Flow Measurements ◽

Physiological Variations

In the recently published article, “Unilateral fetal-type circle of Willis anatomy causes right-left asymmetry in cerebral blood flow with pseudo-continuous arterial spin labeling: A limitation of arterial spin labeling-based cerebral blood flow measurements?”, it was shown by the method of arterial spin labeling (ASL) that unilateral fetal-type circle of Willis could induce variation of blood flow in cerebellar and posterior cerebral artery territory. We believe that the reported observation, rather than being a limitation, gives several interesting cues for understanding the ASL sequence. In this commentary, we formulate some suggestions regarding the use of ASL in clinical practice, discuss the potential causes of the above-mentioned pseudo-asymmetry and consider future improvements of the ASL technique.

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