Diagnostic imaging of patients with acute scrotal pain.

Common causes of acute scrotal pain include testicular torsion, epididymo-orchitis and trauma. Epididymitis in adult men is typically associated with a history of urinary tract infection or prostatitis. Testicular torsion typically presents in young adults with a sudden onset of severe scrotal pain and, frequently, a history of recurrent episodes that have spontaneously resolved. With scrotal trauma, ultrasound may demonstrate testicular fracture, hematoceles and areas of hemorrhage or testicular infarction. Since both epididymitis and testicular torsion present with scrotal pain and swelling, and may be accompanied by fever and pyuria, Doppler ultrasound or radionuclide imaging may be necessary to make the diagnosis. In acute testicular torsion, color Doppler ultrasound shows absent flow to the epididymis and testis, while nuclear imaging shows central photon-deficient areas in the ischemic hemiscrotum. In epididymo-orchitis, color Doppler ultrasound shows increased flow to the epididymis and testis, while nuclear imaging shows increased perfusion of the affected testis and hemiscrotum.