Magnetic resonance imaging of pediatric pelvic masses.

Both benign and malignant pelvic masses are encountered in the pediatric population. Although ultrasonography remains the modality of choice for initial evaluation of a pediatric pelvic mass, in selected cases magnetic resonance (MR) imaging can add important diagnostic information. MR imaging has several advantages over ultrasonography and computed tomography, including superior contrast resolution and an ability to characterize abnormalities based on unique tissue characteristics. MR evaluation assists in lesion characterization, presurgical planning, and staging when a malignancy is suspected. MR imaging also offers a nonionizing imaging modality for long-term follow-up of patients undergoing therapy for malignant pelvic masses.