Analysis of perfusion in patients with vertebrobasilar dolichoectasia through use of multidelay arterial spin labeling magnetic resonance imaging.

Background: The mechanisms underlying stroke or cognitive impairment in patients with vertebrobasilar dolichoectasia (VBD) remain unclear. This study aimed to examine the hemodynamic abnormalities in patients with VBD through use of multidelay arterial spin labeling (ASL) magnetic resonance imaging.

Methods: A retrospective case-control study was conducted and enrolled 30 patients with VBD and 30 healthy participants. Multidelay ASL was used to evaluate the cerebral blood flow (CBF) and arterial transit time (ATT), while carotid Doppler ultrasound was performed to measure extracranial artery flow velocity. The extracranial artery flow velocity and perfusion parameters in the study group and control group were compared. According to the magnetic resonance angiography, VBD in patients was classified as mild, moderate, or severe type. The correlation of the CBF and extracranial artery flow velocity with the severity of VBD was determined.

Results: The mean cerebral blood flow (mCBF) in both the anterior and posterior circulations was lower in the study group than in the control group (P<0.05). The ATT in the study group was significantly longer than that of the control group (P<0.05). In the study group, end-diastolic velocity (EDV) of the right extracranial internal carotid artery was correlated with the mCBF of the right frontal and parietal lobe (P<0.05), whereas the CBF and blood velocity of the vertebral arteries were not correlated. In the control group, the mean peak systolic velocity and mean end-diastolic velocity (mEDV) of the bilateral vertebral arteries were correlated with CBF values of the region of interests in the posterior circulation (P<0.05). There were strong negative correlations between the ATT and mCBF in the control group (P<0.05). No meaningful associations between ATT and mCBF were found in the study group for any region, with the exception of the insula (r=-0.402; P=0.001). There were 7 (23%), 14 (47%), and 9 (30%) cases of mild, moderate, and severe VBD, respectively. Additionally, 10 patients with VBD showed ischemic or infarcted lesions, while 20 had no lesions. The severity of VBD was significantly associated with the mEDV of the bilateral vertebral arteries and the EDV of the right and left extracranial internal carotid artery (P<0.05). There was no association between VBD severity and the occurrence of ischemia (P>0.05).

Conclusions: VBD may lead to brain hypoperfusion, and CBF is not associated with ATT. The hemodynamic disorders in VBD may indicate impaired cerebrovascular autoregulation, which is an underlying mechanism for cerebral small vessel disease.