Sonography of the acute scrotum: the four T's of testicular imaging.

The scrotum is frequently imaged on an emergent basis. The differential diagnosis of the acute scrotum can be divided into four categories-torsion, trauma, tumor, and "testiculitis" (epididymo-orchitis). Although testicular neoplasms are not imaged emergently, 15% are detected incidentally when performing an emergent scrotal ultrasound. Therefore, the emergent sonographic examination of the testicles should include a thorough search for malignancy. Images demonstrating the sonographic and color Doppler appearances of each of the "four T's" will be reviewed. The radiographic review will focus on the imaging features, which are the keys to arriving at the correct diagnosis.