Efficacy of magnetic resonance imaging in 139 children with tumors.

One hundred thirty-nine children with neoplasms were studied using magnetic resonance imaging (MRI). This procedure was as accurate as computed tomography in predicting tumor histology, except that MRI was unable to detect small areas of tumor calcification. Magnetic resonance imaging could accurately identify the organ of origin of tumor masses and differentiate soft tissue from fat, fluid, or hemorrhage. In addition, MRI was helpful in planning surgery in many cases: It was better than computed tomography in defining the size and extent of soft-tissue tumor masses. It was accurate in defining the extent of the spread of bone sarcomas in the bone marrow. Without requiring the injection of intravenous contrast agents, it accurately defined displacement, encasement, or invasion of major abdominal blood vessels by Wilms' tumors and neuroblastomas. As a means of evaluating pediatric neoplasms, MRI is noninvasive, painless, and well tolerated by children, and it uses no radiation.