Sequential assessment of cerebral blood flow in diffuse brain injury by 123I-iodoamphetamine single-photon emission CT.

PURPOSE Our goal was to elucidate the temporal profile of cerebral circulation and its relationship to prognosis in patients with diffuse brain injury by using single-photon emission CT (SPECT) and 123I-iodoamphetamine (IMP). METHODS A total of 67 assessments were made in 26 patients with diffuse brain injury (Glasgow Coma Scale score < or = 8). The microsphere method was used for quantifying cerebral blood flow (CBF). The hemispheric CBF was defined as a mean regional CBF (rCBF), and the total cerebral hemispheric CBF (tCBF) as a mean of the bilateral hemispheric CBF. The relationship between patient outcome and tCBF was investigated. RESULTS The rCBF in patients with diffuse brain injury showed dynamic and global changes with little regional differences. The tCBF values increased in 1 to 3 days, and they were higher in the poor-outcome group than in the good-outcome group. During the period of 14 to 42 days, the tCBF values stayed within normal range in the good-outcome group, whereas they were below normal range in the poor-outcome group. CONCLUSION Our results revealed a good correlation between patient outcome and CBF values. Quantitative and sequential CBF studies with IMP SPECT are promising for helping to determine the prognosis for patients with diffuse brain injury.