What is acute epididymo orchitis, and what are its cross sectional imaging features?
Acute epididymo-orchitis is inflammation of the epididymis and testicle, and it is most often secondary to bacterial infection. It typically presents clinically with fever and scrotal pain and is treated with antimicrobial drugs. US is the initial diagnostic imaging test of choice.
On cross-sectional imaging, key findings may include increased epididymal or testicular size with increased epididymal and testicular blood flow on Doppler US. The testicles may be heterogeneous in echotexture, signal intensity, or enhancement and may have a striated appearance. There may be scrotal skin thickening, a reactive hydrocele or pyocele, and enlargement and increased enhancement of the ipsilateral spermatic cord vessels. Sometimes, the process may be focal, potentially mimicking a testicular neoplasm.
Subsequently, testicular atrophy may occur, along with scarring that manifests as geographic hypoechoic or low T2-weighted signal intensity areas with normal blood flow on Doppler US, sometimes in association with areas of capsular retraction.