REGIONAL CEREBRAL BLOOD-FLOW TRENDS IN HEAD-INJURED PATIENTS WITH FOCAL CONTUSIONS AND CEREBRAL EDEMA

Focal contusions following head injury may be associated with focal or diffuse cerebral edema. Early global hyperemia and perifocal hyperemi a may play a role in cerebral edema, although causal relationships hav e yet to be clearly been defined. We studied 27 patients with head inj ury (admission GCS 3-12) resulting in focal contusions (without eviden ce of subarachnoid, intraventricular or intraparenchymal hemorrhage by CT). Patients were studied with ICP monitors, head CTs, and intraveno us Xenon-133 regional cerebral perfusion studies serially over several days post injury. Low cortical blood flow and a low mean CBF15 flow w ere evident on the day of the injury. Additionally, F1 analysis indica ted significantly (p < 0.05) greater cortical blood flow in the surrou nding brain (mean 60 cc/100 g/min) compared to the contusion area (mea n 43 cc/100 g/min) on the day of trauma. Mean regional CBF remained be low normal in the contused areas (CBF,5 < 35 cc/100 g/min), however th e cortical flow increased in the first few days post-injury (peak Fl = 95 cc/100 g/min on day 3) then decreased to sub-normal levels. The me an CBF in the surrounding brain was low on the day of injury (CBF15 = 29 cc/100 g/min), although higher than the contused area, and increase d to a peak of 45 cc/1009/min on day 3 posttrauma. Cortical flow in th e surrounding brain, however, exhibited a different trend. The mean Fl was low on the day of trauma and significantly higher one day after t rauma (mean 105 cc/100 g/min). Only 15 of the 27 patients with focal c ontusions had evidence of cerebral edema. Eleven of these exhibited fo cal edema and 4 exhibited diffuse edema. Focal edema developed over th e first few days posttrauma as seen in followup CT, whereas patients w ith diffuse edema exhibited edema on the admission CT. Initial oligemi a in the contused areas was associated with a subsequent hyperemic rim about the contusion. Focal hyperemia was associated with focal edema in 41 % of the patients, whereas diffuse edema appeared to be independ ent of the hyperemic response in contusions.