Computed CT scans obtained at the time of clinical presentation have occasionally been reported to be normal in children with a history and findings of significant abusive head injury. Medical personnel have retrospectively observed abnormalities in "normal" scans of some similar children. They have also seen abnormalities develop on serial scanning. In the current study, subjects' CT scans were retrospectively reviewed by a pediatric radiologist. Eleven of the 34 CT scans had initially been interpreted as normal. Four of these had been reinterpreted during the hospitalization as abnormal, affecting medical and legal outcome. Repeat scanning in three of the remaining seven resulted in surgical drainage of a subdural effusion and affected legal outcome. Four of the seven initial scans that diagnosticians believed were normal throughout the hospitalizations were judged abnormal upon eetrospective review. This assessment was confirmed in the two cases rescanned. Initial CT interpretation most often failed to appreciate changes in parenchymal density and small amounts of falcine or cortical subdural blood. Subsequent scans also showed evolving effusions and infarcts. Changes were noted in 1 1/2 to 5 days. The CT scan often shows subtle changes in the immediate posttrauma period. If the child does not recover promptly, subsequent scans often result in significant changes in clinical and legal management. 2 figures and 15 references