Fig. (1) The couples of N20 and 1/vMCA interhemispheric ratio values, detected in each patient without CT/MRI scan alterations in the MCA supplied area, gathered in Table 4, are displayed in the graph in descending order. All N20 and 1/vMCA interhemispheric ratio values were >0.65 and showed significant statistical correlation ( p < 0.01, r = 0.78, 95% C.I. = 0.46 to 0.92).