Novel Hemodynamic Parameters for Cerebral Ischemia in Patients with Occlusive Cerebrovascular Disease Using Dual ASL Perfusion Imaging.

Perfusion MRI via arterial spin labeling (ASL) could not precisely estimate cerebral ischemia severity in patients with occlusive cerebrovascular disease (CVD), because the delayed arrival of arterial blood spins (AB spins) in the affected vascular territories could not be corrected v single post-labeling delay (PLD) setting. In this study, new hemodynamic parameters for cerebral ischemia using dual ASL perfusion imaging under double PLD setting will be proposed.In 67 patients with moyamoya disease (MMD) and 22 patients with large artery atherosclerosis (LAA), hemodynamic parameters were investigated by using dual ASL perfusion imaging via 3.0 T MRI. PLD was fixed to 1525 ms (early image) and 2525 ms (late image). In early images, early slow-in of AB spins into cerebral tissue, and the early stagnation of AB spins within cortical arteries were investigated. In late images, late filling up (complete or incomplete) and both late stagnation and overstagnation were estimated.Early slow-in (65/67 = 97% in MMD, 22/22 = 100% in LAA) and early stagnation (48/67 = 72% in MMD, 7/22 = 32% in LAA) were observed in early images. Late incomplete filling up (22/67 = 33% in MDD, 3/22 = 14% in LAA), late complete filling up (45/67 = 67% in MMD, 19/22 = 86% in LAA), late stagnation (48/67 = 72% in MMD, 10/22 = 45% in LAA), and overstagnation (8/67 = 12% in MMD, 2/22 = 9% in LAA) were identified in late images. Late incomplete filling up (suspected moderate ischemia) in MDD was observed more frequently than was LAA.By using dual ASL perfusion imaging, early slow-in and late filling up as well as early and late stagnation could be identified separately as novel hemodynamic parameters in patients for cerebral ischemia with occlusive CVD.