The false sulcus: an early sign of intracranial mass.

The importance of asymmetry of the cerebral sulci in detecting intracranial mass lesions in the hemisphere where the mass compresses the sulci has been emphasized. Occasionally, the hemisphere that appears to have the large sulci is, in fact, the abnormal side. The apparent large sulci representing early white matter edema are often the earliest computed tomography manifestation of an intracranial mass.