Centrifugal distribution of regional cerebral blood flow and its time course in traumatic intracerebral hematomas

Cerebral blood flow (CBF) alterations following post-traumatic contusions have been demonstrated in recent papers. We evaluated regional CBF (rCBF) by means of Xenon-enhanced computerized tomography (Xe-CT) in 29 traumatic intracerebral hematomas, from 22 patients with severe head injury (GCS less than or equal to 8). Fifty traumatic hematoma/Xe-CT CBF measurements were obtained from 39 Xe-CT studies performed during the acute phase (corresponding to the first 20 days post-injury). The rCBF was measured in three different regions of interest: the hemorrhagic core, the perihematoma edematous low-density area, and a I-cm rim of perihematoma normal-appearing brain tissue, surrounding the edematous low-density area. We found a centrifugal improvement of rCBF as well as a decrease in the rates of CBF levels below 18 mL/100 g/min from the core to the periphery (p < 0.0001), which persisted over time. Ischemic rCBF values were detected in the perihematoma low-density area only in 24% of the traumatic hematomas. The time course of rCBF levels showed a reduced flow in the first 24 h, with a recovery of flow from day 2 to day 4, followed by another reduced flow (p < 0.0001) both in the perihematoma edematous low-density area and in the non-lesioned tissue. Our findings suggest that the only area with persistent ischemic values was the hemorrhagic core. Low rCBF levels seen in the perihematoma low-density area may only be ascribed partially to ischemia and can possibly recover over time. These results could encourage a surgical approach based on an early evacuation of the hemorrhagic core associated to a preservation of the surrounding edematous tissue.