Ultrasound in the assessment of the “on-call” acute scrotum

In the emergency setting, grey-scale ultrasound, with the ability to assess testicular vasculature on colour Doppler, remains the imaging modality of choice for acute scrotal pain. Acute epididymo-orchitis is the most common cause of acute scrotal pain. Acute spermatic cord torsion is seen in 22% of patients presenting with acute scrotal pain. False-negative diagnosis can be made in intermittent spermatic cord torsion and acute torsion–detorsion syndrome. Acute torsion of the testicular appendage is more common than acute testicular torsion. Blunt trauma accounts for 85% and penetrating trauma for 15% of testicular injuries. Testicular rupture is a surgical emergency. The acute scrotum can present a diagnostic dilemma for the clinical team. There are many causes for acute scrotal pain, with ultrasound being key to establishing the diagnosis. Acute epididymo-orchitis is the most common cause of acute scrotal pain. Ultrasound, although not diagnostic of acute spermatic torsion, can help in patient management by establishing other causes of acute scrotal pain. This review details the ultrasound features of the main causes of acute scrotal pain, knowledge of which enables the on-call radiologist to assist the clinical team in making a more accurate diagnosis.