Objective To evaluate collateral flows using vessel encoded arterial spin labeling (VE-ASL) perfusion imaging. MethodsVE-ASL was achieved to assess the presence and function of collateral flow on patients with internal carotid artery (ICA) stenosis. The presence of the anterior and posterior collateral flow was demonstrated by flow patterns of the A1 segment and posterior communicating artery (PCoA).Distal function of collateral flow of stenotic hemisphere was categorized as adequate ( cerebral blood flow ≥10 ml · min-1·100 g-1 ) or deficient (cerebral blood flow < 10 ml · min-1· 100 g-1 ). The results were compared with magnetic resonance angiography (MRA) and intraarterial digital subtraction angiography (DSA) in crosstable by using Kappa values. The VE-ASL before and after ICA stent therapy were compared. ResultsThe Kappa values of the flow patterns of AI segment and PCoA between VE-ASL and MRA were 0. 746 and 0. 700. The Kappa value of the function of collaterals using VE-ASL and DSA was914. VE-ASL showed collateral flow via leptomeningeal anastomoses. VE-ASL changed significantly after ICA steat therapy. ConclusionVE-ASL reveals the presence and distal function of collateral flow, which helps to evaluate the efficacy of ICA steat therapy.

Objective To evaluate a noninvasive vessel encoded imaging for selective mapping of the flow territories of the left and right internal carotid arteries and vertebral-basilar arteries. Methods Seven volunteers [(33.5±4.1) years ; 3 men, 4 women] and 6 patients [(55.2 ± 3.2) years; 2 men,4women] were given written informed consent approved by the institutional review board before participating in the study. A pseudo-continuous tagging pulse train is modified to encode all vessels of interest. The selectivity of this method was demonstrated. Regional perfusion imaging was developed on the same arterial spin labeling sequence. Perfusion-weighted images of the selectively labeled cerebral arteries were obtained by subtraction of the labeled from control images. The CBF values of hemisphere, white matter, and gray matter of volunteers were calculated. The vessel territories on patients were compared with DSA. The low perfusion areas were compared with high signal areas on T2-FLAIR. Results High SNR maps of left carotid, right carotid, and basilar territories were generated in 8 minutes of scan time. Cerebral blood flow 100 g-1 were in agreement with data in the literature. Vessel encoded imaging in patients had a good agreement with DSA. The low perfusion areas were larger than high signal areas on T2-FLAIR. Conclusion We present a new method capable of evaluating both quantitatively and qualitatively the individual brain-feeding arteries in vivo.