Increased detection of intracranial metastases with intravenous Gd-DTPA

Three patients with intracranial metastases were studied with magnetic resonance imaging at 1.5 T before and after intravenous administration of 0.1 mmol/kg gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA). Axial pre- and postcontrast images demonstrated a total of six and 38 metastases, respectively. Of the 35 lesions detected only after administration of contrast material, all were less than 10 mm, and none had evidence of surrounding edema. Lesion conspicuity was comparable on postcontrast mixed (T1, proton density, and T2) images and T1-weighted images, indicating the feasibility of effectively screening for metastases with a single postcontrast spin-echo sequence providing mixed and T2-weighted images. Sagittal and coronal images depicted temporal lobe lesions not seen on axial images. No discomfort, side effects, or complications resulted from the contrast medium. The detection of additional lesions with Gd-DTPA increased the radiologic suspicion of metastatic disease, revealed locations more favorable for biopsy, prompted the search for a primary tumor, and modified therapeutic objectives and methods.