title: Investigation of techniques to quantify in vivo lesion volume based on comparison of water apparent diffusion coefficient (ADC) maps with histology in focal cerebral ischemia of rats.
abstract: Stroke lesion-volume estimates derived from calculated water apparent diffusion coefficient (ADC) maps provide a quantitative surrogate end-point for investigating the efficacy of drug treatment or studying the temporal evolution of cerebral ischemia. Methodology is described for estimating ischemic lesion volumes in a rat model of permanent middle cerebral artery occlusion (MCAO) based on absolute and percent-reduction threshold values of the water ADC at 3 h post-MCAO. Volume estimates derived from average ADC (ADC(av)) maps were compared with those derived from post-mortem histological sections. Optimum ADC thresholds were established as those that provided the best correlation and one-to-one correspondence between ADC- and histologically derived lesion-volume estimates. At 3 h post-MCAO, an absolute-ADC(av) threshold of 47 x 10(-5) mm(2)/s (corresponding to a 33% reduction in ADC(av) based on a contralateral hemisphere comparison) provided the most accurate estimate of percent hemispheric lesion volume (%HLV). Experimental and data analysis issues for improving and validating the usefulness of DWI as a surrogate endpoint for the quantification of ischemic lesion volume are discussed.
authors.affiliation: Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Kazemi
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Silva
authors.forename: Fuhai
authors.initials: F
authors.lastname: Li
authors.forename: Marc
authors.initials: M
authors.lastname: Fisher
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Sotak
mesh_terms: D000208:Acute Disease; D000818:Animals; D002545:Brain Ischemia / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D020768:Middle Cerebral Artery / Q000473:pathology; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors