Perfusion Territory Shifts in Cerebrovascular Diseases Measured by Super‐Selective Arterial Spin Labeling

Background and Purpose Individualized diagnostic approaches are crucial in cerebrovascular diseases, such as internal carotid artery stenosis (ICAS). To evaluate individual collateral blood supply, vessel‐selective imaging has gained high relevance. However, clinically established digital subtraction angiography (DSA) exposes patients to intervention risks and radiation. Two noninvasive MRI‐based alternatives are super‐selective pseudo‐continuous arterial spin labeling (ss‐pCASL, a technique for selective labeling of arterial blood‐water) for perfusion territory mapping and four‐dimensional vessel‐selective angiography (4D‐sPACK). We hypothesized that asymptomatic atherosclerosis‐induced ICAS and Moyamoya disease result in chronic malperfusion. Therefore, we aimed towards quantitative assessment of collateral blood flow by ss‐pCASL. Methods In this prospective monocentric study, we acquired data in three subgroups ( n = 23): patients with asymptomatic unilateral atherosclerosis‐induced ICAS, Moyamoya disease, and age‐matched healthy controls (HCs). On the basis of vascular territories from ss‐pCASL, we introduced four parameters: volume, territorial shift, overlap with an atlas, and cerebral blood flow (CBF). For patients with atherosclerosis‐induced ICAS, ipsi‐ and contralateral hemispheres were compared (paired t ‐test), and hemispheric lateralization Δ was calculated subjectwise and compared between patients and HCs (unpaired t ‐test) ( p < 0.05). Results We included data from 20 subjects (8 ICAS, 3 Moyamoya, 9 HC). Group‐level results showed ICAS‐induced shifts with significant lateralization compared to HCs ( Δ Volume,ICAS = 18% ± 10%, p < 0.001; Δ Shift,ICAS = 4.9% ± 5.8%, p = 0.027; Δ Overlap,ICAS = 0.2 ± 0.3, p = 0.033, Δ CBF,ICAS = 3 ± 3 mL/100 g/min, p = 0.045). Furthermore, collateral blood supply in Moyamoya disease was assessed by 4D‐sPACK and showed comparable diagnostic value as DSA. Conclusion Perfusion territory mapping by ss‐pCASL revealed chronic malperfusion in asymptomatic ICAS that can be objectively quantified, and 4D‐sPACK added diagnostic value similar to DSA.