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

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.

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).

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.

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.