Magnetic resonance imaging for localizing the nonpalpable undescended testis.

A prospective evaluation of the value of magnetic resonance imaging (MRI) for localizing the nonpalpable undescended testis was performed in 17 boys aged 1 year to 5 years 4 months who had a clinical diagnosis of nonpalpable testes. The results were compared between the MRI, ultrasonographic, clinical, and definitive surgical diagnosis in all patients. Nine nonpalpable undescended testes were identified in the inguinal canal or just proximal to the inguinal ring by MRI, and these were confirmed by surgical findings. Six nonpalpable testes were not observed by MRI, and the absence of these testes was surgically confirmed. Like scrotal testes, all the undescended testes showed a low intensity on sequences with a short repetition time (TR) and echo time (TE), and a high intensity on long TR/TE sequences. Undescended testes were observed better on coronal images than on axial images. MRI promises to become an important diagnostic tool in the detection of nonpalpable undescended testes.