[Diffuse hemispheric low density on CT scan following acute interhemispheric subdural hematoma in an infant. Case report].

A 17-month-old boy was admitted to our hospital in a semicomatose state after a minor head injury. Computed tomography (CT) scans revealed a posterior interhemispheric and a thin convexity subdural hematoma. Two and a half hours later, repeated CT scans disclosed a development of the right hemispheric diffuse low density and an enlargement of the interhemispheric subdural hematoma. Decompressive craniectomy and removal of the hematoma was performed immediately. On the second postoperative day, the diffuse low density areas developed in the contralateral frontal and temporal lobes. On the 14th postoperative day, the gyri which had been low in density were markedly enhanced with contrast enhancement. On the 16th postoperative day, CT scans showed a diffuse hemispheric gyral high density with bleeding in the right parieto-occipital lobe. A right occipital lobectomy and removal of the hematoma was performed. Histological examination suggested cerebral infarction probably due to venous congestion. It is also suggested that the diffuse hemispheric gyral high density observed on the 16th postoperative day was the hemorrhagic cerebral infarction.