Figure 4.

Co-registered PET and DW Images from an ischemic stroke patient. Figure 4(A) illustrates the main finding that the DWI lesion contains both core and penumbral tissue. Row 5 illustrates the core (CMRO2, CBF) and penumbra (OEF) voxels (red and green contours, respectively) with the DWI ROI superimposed (black contours). As expected, the relative proportion of penumbra was highest at the dorsal- and ventral-most regions of the middle cerebral artery territory, and lowest in its centre. In Figure 4(B) Co-registered day 30 high-resolution spoiled gradient echo sequence scan show final infarct (equivalent slices to Figure 4(A). Superimposed are the PET core defined by CMRO2 and CBF (red) and penumbra defined by OEF (green). The PET-derived ROIs were interpolated to the higher-resolution magnetic resonance image. Visual assessment confirms that, bearing in mind a 95% probabilistic threshold, the core ROI translates into infarcted tissue, whereas the penumbra ROIs (as expected) have a mixed outcome, which would fit with the documented associated clinical improvement of the patient from an NIHSS of 16 to 9. Comparing the DWI lesion ROI from Figure 4(A), it can be seen that most of it progresses to infarction, but note the variable DWI lesion intensity. In these images, the right hemisphere is on the right. Modified and reproduced with permission [60].