Sonographic appearance of the epididymis in pediatric testicular torsion.

OBJECTIVE: The purpose of this study was to determine the frequency of an enlarged epididymis in pediatric patients with testicular torsion and to determine whether an altered epididymis might be a helpful ancillary sonographic sign of testicular torsion.
MATERIALS AND METHODS: The sonograms of 50 pediatric patients (age range, neonate-17 years) with testicular torsion were retrospectively reviewed for the size, appearance, and blood flow of the epididymis. Medical records were reviewed for surgical and pathologic findings and to determine whether testicular salvage had been possible.
RESULTS: The epididymis was enlarged (maximum dimension, 5.5 cm) in 47 of the 50 patients with acute or late phase torsion and after manual or spontaneous detorsion. The average difference in volume between the ipsilateral epididymis and the contralateral epididymis was 30 cm3, highly significant (p < 0.0001). The shape of the epididymis was altered in 92% of the cases (globular, bilobular, or multilobular). Seventy-three percent showed increased echogenicity and 27% appeared isoechoic. Of those with active torsion, 93% of the epididymides were avascular; 2%, hypovascular; and 5%, hypervascular. After detorsion, 100% of the epididymides (10/10) had blood flow. In patients with testicular loss due to infarction, pathology showed engorgement and enlargement of the epididymis with hemorrhagic infarction. In one patient with a hypervascular epididymis, surgery showed inflammation and erythema of the epididymis. Testicular loss occurred in each type of epididymal flow pattern.
CONCLUSION: A markedly enlarged, echogenic, and avascular or hypovascular epididymis is an ancillary sonographic sign in pediatric patients with testicular torsion. A hypervascular enlarged epididymis infrequently occurs (5% of cases) and should not be mistaken for epididymitis. In addition, the return of epididymal blood flow is an ancillary sign of successful testicular detorsion.