Abstract
Patients with asymptomatic occlusion in the internal carotid arteries (ICA) have been shown to have a better preserved hemodynamic status of the brain as compared to patients with symptoms. This study was aimed to explore the cerebral perfusion alterations in asymptomatic patients using multi-parametric arterial spin-labeling (ASL) magnetic resonance (MR) imaging. Forty-two patients diagnosed with asymptomatic ICA stenosis/occlusion were prospectively included and divided into high-grade (ultrasonographic stenosis ≥70%, N = 20) and low-grade groups (N = 22). On a 3-Tesla clinical MR scanner, pseudo-continuous ASL was performed to measure cerebral blood flow CBF, arterial transit time ATT, and flow territory. Fisher's exact test indicates that the high-grade group has higher frequency in asymmetric ATT (p < 10(-3)) and asymmetric flow territory (p < 10(-3)) as compared to the low-grade group. The between-group difference in CBF asymmetry is marginal (p = 0.062). Logistic regression further reveals that hemispherical asymmetry in ATT and flow territory is associated with the existence of high-grade ICA stenosis (odds ratio = 12 and 21, respectively), whereas hemispherical asymmetry in CBF is not. Our data suggest that ATT and flow territory may be better predictors of asymptomatic high-grade ICA stenosis diagnosed by carotid ultrasonography than CBF.