The potential of magnetic resonance (MR) imaging in the evaluation of the female urethra was studied in 64 patients. Spin-echo T1- and T2-weighted images were obtained in all 64 patients, and contrast-enhanced T1-weighted images were also obtained in 27 patients. Urethral pathologic conditions, established with urethroscopy or histologic examination, or both, included urethral diverticula, inflammatory granuloma, and primary and metastatic neoplasms. On T2-weighted images, all normal urethras demonstrated a characteristic targetlike appearance with differentiation among the outer ring of low signal intensity, the middle zone of higher signal intensity, and the center of low signal intensity. After injection of gadopentetate dimeglumine, the targetlike appearance of the normal urethra was seen on the T1-weighted images. Urethral diverticula were detected with MR imaging in all nine patients with that diagnosis, and in each, MR imaging demonstrated urethral expansion, distortion of the zonal anatomy, and presence of fluid in the middle zone. Primary or metastatic urethral neoplasms were also detected with MR imaging in every patient with the diagnosis, but differentiation between benign and malignant disease was not possible. Local staging of primary or metastatic malignant disease was correct in eight of the 11 patients. In three patients, the inflammatory changes could not be differentiated from tumor invasion, resulting in overestimation of tumor extent.
