White matter buckling: CT sign of extraaxial intracranial mass

The resolution of present day computed tomography (CT) scanners routinely permits discrimination of gray from white matter with delineation of a gray-white matter interface. Superficially situated extraaxial masses usually preserve the gray-white interface and tend to compress and/or buckle adjacent edematous white matter. This does not occur with superficially situated intraaxial lesions and is, therefore, essentially diagnostic of an external mass. It is postulated that this sign reflects the relative resistance of gray matter to edema in conjunction with the destruction of the gray-white interface by the infiltration of intraaxial lesions. White matter buckling is almost invariably associated with extracerebral fluid collections. It is less often discernible in association with meningioma. In a series of 100 consecutive proven meningioma cases, compression and/or buckling of central white matter was demonstrated in 28, and in 28 (40%) of 70 superficially situated lesions. White matter buckling is diagnostically significant when it occurs. It has been especially helpful in the diagnosis of otherwise atypical superficial masses.