Gd-DTPA in clinical MR of the brain: 2. Extraaxial lesions and normal structures.

Fifteen patients with suspected extraaxial tumors were evaluated with MR before and after intravenous injection of Gadolinium-DTPA (Gd-DTPA). Meningiomas (7), neurinomas (4), chordomas (2), a previously irradiated dural metastasis, and a giant aneurysm were studied. All the lesions except the dural metastasis enhanced. In two patients with asymptomatic meningiomas, the use of Gd-DTPA with MR allowed definitive diagnosis of the lesions when the routine MR did not. Gd-DTPA also provided improved definition of intracranial tumor margins, produced differential enhancement of dura and nasopharyngeal mucosa from tumor, and caused enhancement of the choroid plexus, some venous structures, the pituitary gland, and its stalk. The enhancement of the pituitary suggests a role for Gd-DTPA in the diagnosis of microadenomas. Routine T2-weighted images without Gd-DTPA were useful in differentiating neurinomas from meningiomas. Judicious use of Gd-DTPA should improve the ability of MR to detect extraaxial lesions, delineate their extent, and characterize their perfusion.