Rapid spontaneous resolution of acute subdural hematoma occurs by redistribution--Two case reports.

Coronal magnetic resonance imaging provided evidence of redistribution during the rapid spontaneous resolution of acute subdural hematoma (ASDH) in two patients. A 79-year-old female was transferred to our hospital after a traffic accident. Computed tomography (CT) on admission demonstrated an ASDH in the right frontal cerebral cortex. CT 12 hours after the accident revealed spontaneous resolution of the ASDH. Coronal magnetic resonance (MR) imaging 3 days after the accident clearly detected a very thin, sharply demarcated layer diffusely covering the cerebral convexity and the middle cranial fossa. A 41-year-old female fell and sustained head trauma with the loss of consciousness. CT on admission demonstrated an ASDH in the left frontal cerebral cortex. CT 12 hours after the accident revealed spontaneous resolution of the ASDH. Coronal MR imaging 3 days after the insult clearly demonstrated the redistribution and dispersal of the hematoma. Although CT showed the disappearance of the hematoma, MR imaging demonstrated redistribution rather than disappearance of the blood in both cases. These cases indicate that spontaneous resolution of ASDH occurs by redistribution and dispersal of the hematoma.