OBJECTIVE: To assess the relationship between the prognosis of the patients with diffuse traumatic brain swelling (DTBS) and the changes of the ventricles and the cisterns in CT scans. METHODS: The outcome of the patients with DTBS and the changes of the ventricles and the cisterns in CT scans were studied and analyzed in a group of 268 cases. We focused on the changes of the third ventricle and the basal cistern, age and Glasgow Coma Scale (GCS). RESULTS: Of 268 cases, there were changes of the third ventricle and/or the basal cistern in 124, 65 died. In l8 cases, the third ventricle and the basal cistern were both absent and l6 died (88.9%). The third ventricle changed significantly in 59 cases, 33 died (55.9%), while the basal cistern changed in 47 cases and 16 died (34%). Of the 124 patients with changes of the third ventricle and/or the basal cistern, 26 were children, 8 died; 98 adults, 57 died. CONCLUSIONS: For patients with DTBS, the outcome was in direct correlation with the change of the third ventricle and/or the basal cistern, the change of the third ventricle was much more important in assessment of the outcome than that of basal cisterns. There is no significant difference in, the incidence of DTBS between children and adults while the outcome of children is much better than that of adults. The patients with the changes of the third ventricle and the basal cistern accompanied with lower GCS scores have poor outcome.