Computed tomography in the evaluation of subdural hematomas.

Computed tomographic (CT) scans used in the diagnosis and management of subdural hematomas were analyzed with respect to their contribution to angiography and surgery. There has been a progressive increase in the use of CT in evaluating post-traumatic and postoperative subdural hematomas at the Mayo Clinic. At present, 40% of all patients undergo operation on the basis of the CT findings alone. False-positive diagnoses revealed at surgery have decreased to less than 4%. Erroneous negative interpretations have involved 10% of all patients whose diagnosis was subdural hematoma. Criteria for the interpretation of scans have been established.