Fig. 8. In vivo APTw vs. pH_enh results from rat brain with MCAO.

(A–B) APTw and pH_enh from two rat brains measured at 2 h post MCAO were shown with two different scale bars of 10% and 6% of contrast. (C) Respective ADC maps showed the ischemic core region in the ipsilateral hemisphere. Due to the large background heterogeneity of APTw, clear delineation of ischemic lesion is problematic, and its identified lesion area (red) is smaller than that of the ADC map (yellow). Compared to the negative contrast of APTw, the lesion can be better identified with the positive contrast of pH_enh, which matches well with the ADC map. With appropriate thresholding, the lesion area can be determined in the pH_enh map, except pixels at the ventricle region and at the boundary of the brain. (D) The magnitude of contrast between ipsilateral and contralateral ROIs, defined in the ADC maps as dashed and solid contours, respectively, is higher for pH_enh than that for APT_W.