POSITRON-EMISSION-TOMOGRAPHY IN ISCHEMIC STROKE - CEREBRAL PERFUSION AND METABOLISM AFTER STROKE ONSET

PET studies were performed in 37 patients up to 1 month after ischaemi c stroke to observe the relationships between cerebral blood flow (CBF ), rate of cerebral oxygen metabolism (CMRO2) and oxygen extraction fr action (OEF) with time. PET findings were classified as misery perfusi on (two patients), luxury perfusion (15 patients), matched hypoperfusi on-hypometabolism (17 patients) or normal (nine patients). Misery perf usion was seen up to 3 days post-stroke, suggesting an extended time w indow during which at least some tissue may be salvageable. Luxury per fusion, an indication of non-nutritional flow, was seen as early as 30 h and as late as 23 days, but more commonly between 3 and 7 days. A m atched reduction of CBF and CMRO2 was seen during all time periods, bu t as early as 27 hours. Since this was associated with severely impair ed CBF, presumably from the onset of stroke, it can be assumed that th e duration of cerebral tissue survival is less than 27 h under these c onditions. We inferred that, for maximal tissue recovery, therapy will need to be introduced within 27 h after stroke, but that at least som e potential for recovery exists up to 3 days.