Unenhanced and gadolinium-DTPA-enhanced MR imaging in postoperative evaluation in pediatric brain tumors.

Gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) is a chelated paramagnetic contrast agent under clinical trial for use in magnetic resonance (MR) imaging. The increased signal intensity following the intravenous infusion of contrast medium may improve the ability of MR imaging to delineate tumors. The use of this method in 15 pediatric patients with suspected brain-tumor recurrence was analyzed. All 15 patients underwent postoperative Gd-DTPA-enhanced MR imaging, and residual tumor was demonstrated in nine of them. Based on the findings of the enhanced MR studies, four patients had additional surgery, two underwent radiation therapy, and one was given immunotherapy. Continued surveillance was recommended for the remaining eight patients. In all cases the enhanced MR imaging studies were superior to the unenhanced studies in regard to the qualitative and quantitative assessment of the residual tumor. Gadolinium-DTPA-enhanced MR imaging appears to be a safe and effective means of providing an accurate postoperative assessment of residual disease in pediatric brain-tumor patients. It is as effective as contrast-enhanced computerized tomography and has the sensitivity and anatomic resolution provided by MR imaging. The most useful role of this agent was in the postoperative period, in assessing the adequacy of surgical resection. This technique is recommended as the procedure of choice in the postoperative assessment and long-term surveillance of patients with brain tumors.