Magnetic resonance imaging of optic nerve meningiomas. Enhancement with gadolinium-DTPA.

Abstract

Six patients with optic nerve sheath meningiomas were studied with gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) to evaluate intracranial extension. The intraorbital and intracranial tumors were isointense to cortical gray matter on T1-weighted studies without contrast in all patients. After Gd-DTPA, three patients showed mild enhancement of the intraorbital tumor, whereas five of six patients showed vivid enhancement of the intracranial tumor. In four cases, the intracranial extension could not be definitely seen on MRI without Gd-DTPA. Two patients had proton density and T2-weighted studies; in each case, the intraorbital tumor remained nearly isointense. The intracranial tumor was suggested in one patient on T2-weighted studies, but was poorly defined. Gadolinium-DTPA has proved valuable in detecting intracranial extension of optic nerve meningiomas that are not well visualized on standard MRI without contrast.