Method and system for mapping tissue status of acute stroke

A system of identifying ischemic lesions in a subject, the system comprising:

• scanning means for acquiring a perfusion image data of the subject, wherein a contrast agent is administered to the subject during a dynamic imaging scan;
• storage means for retrieving or receiving image data from the scanning means;
• processor means comprising:
• a. loading said perfusion imaging data into an electronic memory means, wherein said perfusion imaging data contains information of a contrast agent passing through a region of interest (ROI), wherein said ROI comprises tissue;
• b. measuring a global arterial input function AIF from a normal major artery, wherein said AIF is an intensity profile measured against time;
• c. measuring a tissue contrast agent curve C(t) in said tissue, wherein said C(t) is an intensity profile measured against time;
• d. deriving perfusion maps by deconvolution of said AIF from said C(t) on a pixel-by-pixel basis using a delay and dispersion compensated deconvolution method, wherein said perfusion maps comprise an arterial delay time (DT) map and cerebral blood volume (CBV), cerebral blood flow (CBF) and mean transit time (MTT) maps;
• e. determining ischemic lesion pixels from said perfusion imaging data, wherein said DT is greater than a predetermined first threshold value and said CBV is below a second threshold value.
• f. applying a cluster analysis to said ischemic lesion by removing small islands or filling small holes, wherein the said small island[s] or small holes have a maximum cluster size below a predetermined fifth threshold value.