1. A method for assisting diagnosis of stroke by image analysis, the method comprising: obtaining a scanned brain image of a patient; transforming the scanned brain image into a digitized brain image; removing bone and other artifacts from the digitized brain image; generating at least one circular adaptive region of interest with a center (X c , Y c ) and radius r on one side of the brain image; generating a binary mask of the circular adaptive region of interest; calculating the percentage of zeros (P 0 ) from the binary mask within the circular adaptive region of interest; increasing the radius of the circular adaptive region of interest if P 0 is greater than a cutoff value; locating at least one corresponding circular adaptive region of interest on the other side of the brain image; and comparing the circular adaptive region of interest with the corresponding circular adaptive region on interest of the other side of the brain based on a plurality of texture attributes.