Figure 7.

Peri-infarct depolarization (PID) incidence, infarct volume, regional cerebral blood flow (CBF), and the effect of hyperglycemia. Correlations are shown for individual animals that contributed to the data of Figure 6, with inclusion of additional data from hyperglycemic animals. Group designations are omitted for clarity. Upper panel: There was a general correlation between PID incidence and infarct volume below a threshold of approximately 10 PIDs, above which infarct size was constant over a wide range of higher PID incidence. (Shaded bar, naive 24 hour infarct volume±1 s.d.) Middle panel: Reduced PID incidence was associated with improved perfusion of distal middle cerebral artery (MCA) territory in normoglycemic animals, whereas hyperglycemia decreased PID number independent of penumbral perfusion. Lower panel: Penumbral perfusion was inversely correlated with infarct volume, with little effect of blood glucose on the relationship. (Line indicates best fit for normoglycemic animals.)