Direct Comparison of Local Cerebral Blood Flow Rates Measured by MRI Arterial Spin-Tagging and Quantitative Autoradiography in a Rat Model of Experimental Cerebral Ischemia

摘要: The present study determined cerebral blood flow (CBF) in the rat using two different magnetic resonance imaging (MRI) arterial spin-tagging (AST) methods and 14C-iodoantipyrine (IAP)-quantitative autoradiography (QAR), a standard but terminal technique used for quantitating CBF, compared resulting data sets to assess precision accuracy of techniques. Two hours after ischemia was produced eight rats via permanent occlusion one middle artery (MCA) with an intraluminal suture, MRI-CBF measured over 2.0-mm coronal slice single-coil AST, tissue magnetization assessed by either spin-echo (SE) or variable tip-angle gradient-echo (VTA-GE) readout. Subsequently ( approximately 2.5 MCA occlusion), CBF assayed QAR indicator 14C-IAP, which images local rates every 0.4 mm along rostral-caudal axis. IAP-QAR that spanned 2-mm MRI were selected, regional (i.e., [lCBF]) averaged across this set both traditional approach, involved reader interaction avoidance sectioning artifacts, whole film-scanning technique, approximated total radioactivity entire minimal user bias. After alignment coregistration, concordance generated approaches AST examined nine regions interest each hemisphere. QAR-lCBF higher method assaying than MRI-analog approach; although highly correlated, scatter broad. obtained chosen subsequent comparisons results because similarity "sampling" among these three methods. As predicted previous modeling, "true" rates, assumed be given QAR-lCBF, tended slightly lower those SE appreciably VTA-GE. When ischemic contralateral hemispheres considered together, SE-CBF VTA-GE-CBF correlated P 80 mL. 100 g(-1). min(-1) ), whereas values more accurate low-flow (ipsilateral) areas (CBF < or= 60 ). Accordingly, concurrent usage AST-MRI VTA-GE alone would preferred human studies stroke.