Nuclear magnetic resonance imaging of the hydrogen nucleus provides a unique noninvasive display of proton dynamics in biologic tissues and fluids as well as internal anatomy in a sectional imaging format. No ionizing radiation is utilized. Our experience with NMR imaging of the brain in 14 pediatric patients is presented and compared with computed tomography. The major advantages of NMR over CT include its greater sensitivity to blood flow, edema, hemorrhage, and myelinization and its lack of beam-hardening artifacts. In addition, the potential for tissue characterization exists by determination of T1 and T2 relaxation times and of mobile proton density. Disadvantages of NMR over CT include its failure to demonstrate calcification and bone detail and longer data acquisition times.