Study of perfusion in and around cerebral contusions by means of computed tomography

Several authors have found low absolute values of cerebral blood flow (CBF) in both contusion core and pericontusional parenchyma ofhead-injured patients by means of Xenon Computed Tomography (CT). Perfusion CT has become available as a new and validated tool for studying CBF in patients. The aim of the present study was to assess the relation between volume expansion of contusions and pericontusional CBF measured by perfusion CT.

Eight head-injured patients with a contusion on the admission CT head scan underwent a perfusion CT scan within 48 hours post trauma. The patients received standard head injury management. The eventual maximum contusion volume was assessed on the follow up plain CT scans.

Expansion of the contusion was observed in 6 patients. Reduced CBF was found in all contusions with absolute CBF values below 10 ml/100 g/min in the CT hyperdense/mixed density areas and below 20 ml/100 g/min in the surrounding hypodense areas. Penumbra areas, when defined by a mean transit time > 150% and cerebral blood volume > 2 ml/100 g, were limited to thin concentric rims surrounding the ischemic cores. We could not find a pattern of CBF that predicted contusion expansion.

Based on the present preliminary data there is no indication that contusion expansion can be predicted on the basis of pericontusional CBF data.