Multiphase Arterial Spin Labeling Assessment of Cerebral Perfusion Changes Associated with Middle Cerebral Artery Stenosis

Rationale and Objectives: To assess the sensitivity and utility of multiphase pulsed arterial spin labeling (PASL) in detecting dynamic changes of cerebral perfusion in the presence of a middle cerebral artery (MCA) severe stenosis. Materials and Methods: Seventeen patients with severe stenoses in unilateral M1 segment of MCA were involved in this study. All patients underwent multiphase PASL imaging. Bilateral basal ganglia were drawn by hand as regions of interest (ROIs) on eight-phase images of each patient. The signal intensities of ROIs were measured and the time-intensity curves (TICs) were acquired through postprocessing on a magnetic resonance workstation. Whether there was a significant difference in the peak signal intensities of ROIs between the narrowed and normal sides was determined by the paired samples t test. Results: Three types of TICs were observed: eight cases with platform type, five cases with two-peak type, and four cases with single-peak type. There was a significant difference in the peak signal intensities of ROls between the narrowed and normal sides. Conclusions: Different types of TICs represent different cerebral hemodynamic changes. Multiphase PASL can sensitively detect the dynamic characteristics of cerebral perfusion and provide important dynamic perfusion information for clinical treatment of arterial stenosis.