Gadolinium enhancement of benign extraaxial neoplasms

Benign extraaxial neoplasms have little contrast with respect to brain tissue in conventional MR imaging. Since these tumors lack a blood-brain barrier, intravenous Gd contrast enhancement should, in theory, improve their MR detection. Gd contrast enhancement was studied in 18 patients with extraaxial tumors at 1.5 T. T1-weighted images were obtained before and at 3 minutes, 25 minutes, and 55 minutes after intravenous Gd injection. Signal-intensity enhancement was maximal at 3 minutes post-Gd administration. Acoustic neuromas demonstrated the greatest enhancement (average 360%); meningiomas the next greatest (average 180%); and neurofibromas, glomus tumors, and pituitary adenomas less enhancement. No patient reactions to the contrast medium were observed