Observation of Mean Transit Time (Mtt) Perfusion Maps on a 320-Detector Row Ct Scanner and its Potential Application in Acute Ischemic Stroke

Abstract

Background and Purpose: We present three patients with acute ischemic stroke who underwent computed tomography perfusion (CTP) imaging utilizing an Aquilion ONE (Toshiba Medical Systems, Nasu, Japan) 320-dectector row CT scanner using a Singular Value Decomposition Plus (SVD+) algorithm to generate perfusion maps. These MTT maps may prove to be a sensitive and specific predictor of ischemic penumbra (IP) and infarct core (IC). Methods: Patients, who presented with an acute ischemic stroke, received high quality whole-brain CTP scans and a follow up MRI or non-contrast CT (NCCT) scan, and underwent successful pharmacological and/ or interventional reperfusion procedures were selected for evaluation. A neuroradiologist utilizing Vitrea FX 3.1 software reviewed images, and the IC volumes were calculated. Results: A comparison was made between the volumes of infarct core utilizing SVD+ MTT maps and DWI MR sequences or a sub-acute NCCT. There was a correlation between the infarct core volume measured on MTT and final infarct volume on follow up imaging. However due to limitations associated with a small sample size, a statistical correlation cannot be definitively calculated from this data set. Conclusions: Utilization of the SVD+ MTT map may allow for a more accurate assessment of the infarct core and surrounding salvageable tissue as compared to cerebral blood flow/cerebral blood volume (CBF/CBV) mismatch though further studies are required to validate this observation.