Method of ROI delineation and pixel-wise texture analysis from the gray level co-occurrence matrix (GLCM).

<p>a) Axial-transverse post-contrast T1-W image showing multiple enhanced lesions. b) T2-W image in similar slice location revealing additional hyper-intense unenhanced lesions. c) Segmentation on the same image as in b) of the largest active lesion as well as the contralateral mirrored area within NAWM. d) Corresponding DWI with gradient factor b_o = 0 s.mm^-2. e) Corresponding DWI with gradient factor b = 1000 s.mm^-2. f) ADC parametric map registered on anatomical T2-W image with superimposition of the ROIs drawn on c. g) Zoom of ADC mapped image on largest enhanced lesion (after erasing ROIs’ contours). h-m) Parametrical maps of the following texture parameter: h) contrast, i) correlation, j) homogeneity, k) sum average, l) sum variance and m) difference variance with mean value estimated on a 3x3 sliding window and normalized on the 0–255 range. Individual texture parameters revealed different local and regional statistical properties of the gray levels between MS lesions and NAWM and between enhanced and unenhanced MS lesions.