Image Analysis Method.
Infarct (pink) was identified on a PET image (top left) acquired 160-185min after ET-1 injection as pixels in the affected side ROI with signal below the infarction threshold derived from the contralateral ROI. Pixels with signal above this threshold were classified as non-infarct (yellow). The average image (top right) was used to segment out white matter. Blood vessels were identified on the BV map (bottom left) using a threshold derived from the affected side ROI (see text). Grey matter, vessel-less infarct and non-infarct ROIs were then superimposed onto the median CBF map (bottom right).