Correlation of acute-phase cerebral blood flow and MRI findings with outcome in patients with diffuse axonal injury

The purpose of this study was to assess the utility of acute-phase cerebral blood flow (CBF) measurements and magnetic resonance imaging (MRI) for predicting the outcome of patients with diffuse axonal injury (DAI). Twenty-one DAI patients treated at our hospital between July 1997 and December 1999 were evaluated. CBF was measured using Xenon computed tomography. Axial T1-, axial T2-, and sagittal T2-weighted MRI scans were performed using a 0.5 Tesla MR scanner. Each examination was performed within seven days of the onset of symptoms. Patients were divided into two groups according to their Glasgow outcome scale after six months: a good outcome group (n=14, good recovery or moderate disability), and a poor outcome group (n=7, severe disability, vegetative state or death). We compared the inter-group average ages, Glasgow coma scale (GCS) ratings upon admission, and CBF values using the Student t-test. Inter-group differences regarding the presence of lesions on MRI images were assessed using the Mann-Whitney test. The age of the good outcome group was significantly lower than that of the poor outcome group (31.4±15.1 years vs 49.6±24.1 years; p<0.05). The GCS ratings were not significantly different (7.1±2.2 vs 5.9±1.5). The CBF of the good outcome group tended to be higher than that of the poor outcome group, but the difference was not statistically significant (43.2±12.8 ml/100 g/min vs 33.6±7.4 ml/100 g/min). The presence of lesions in the thalamus and brain stem on MRI images was correlated with the outcome of the patients, especially in patients with a lesion in their brain stem (p<0.01). Lesions in the corpus callosum were observed in both groups, and their presence was not correlated with patient outcome. We conclude that DAI patients who are older or whose MRI examinations reveal the presence of a lesion in their brain stem may have difficulty leading an independent daily life and that the prognosis of acute-phase DAI patients cannot be predicted on the basis of CBF values alone. (author)