Acute painful scrotum.

The ability of US to diagnose the pathogenesis of the acute scrotum is unsurpassed by any other imaging modality. It is the first imaging performed in patients with acute scrotum. Knowledge of the normal and pathologic sonographic appearance of the scrotum and proper sonographic technique is essential for accurate diagnosis of acute scrotum. High-frequency transducer sonography combined with color flow Doppler sonography provides the information essential to reach a specific diagnosis in patients with testicular torsion, epididymo-orchitis, and testicular trauma.