Findings: An ultrasound exam of the testes demonstrates the right testis to be enlarged with multiple hyper and hypoechoic areas. Also, no doppler flow can be seen within the right testis.
Diagnosis: Torsion and infarction of the right testicle.
Discussion: Testicular torsion refers to the actual twisting of the spermatic cord in an attached testis one or more times. Torsion is most common in the neonatal period as well as within adolescence. After the neonatal period, testicular torsion produces acute scrotal pain and swelling. Approximately 40% of boys with acute scrotal pain do have testicular torsion. Boys with a "bell-clapper" deformity in which the tunica vaginalis invests not only the testicle but the epididymis and distal spermatic cord resulting in excessively mobile testicle are at a higher risk for testicular torsion. Preservation of hormonal and spermatogenetic function is usually only possible in patients whose ischemia is relieved within 6 to 10 hours, thus making prompt diagnosis and therapy imperative. In neonates with testicular torsion, often a firm, painless mass and a discolored scrotum is seen, and salvage of the testis is very rare.
In the past, testicular scintigraphy was the best imaging modality for diagnosis of acute testicular torsion. With torsion of less than 24 hours in duration, a cold defect is seen within the affected testis. With the advent of color doppler sonography ultrasound has replaced scintigraphy as the imaging modality of choice. In the early stages of torsion, the ultrasound image appears normal up to approximately four hours after the spermatic cord is twisted. However, spectral and color doppler are abnormal during this period, demonstrating absence of blood flow within the affected testis. The ultrasound image becomes abnormal after approximately four hours, demonstrating an enlarged, hypoechoic testicle. After approximately ten hours, the testicular parenchyma becomes heterogeneous due to hemorrhaging necrosis. Other findings include enlarged epididymis, reactive hydrocele and scrotal wall thickening. Doppler imaging continues to demonstrate absence of flow within the affected testicle. However, increased flow may be identified in these later phases in the scrotal wall as a result of reactive hyperemia.
If the condition is left untreated, the swelling resolves, and the testicle ultimately atrophies. An ultrasound exam at this phase would demonstrate a small hypoechoic testicle.
References:
Barnewolt CE. Genitourinary Tract. Practical Pediatric Imaging Diagnostic
Radiology of Infants and Children, 3rd Edition. Kirks DR. Lippincott-Rave,
Philadelphia; 1998:1154-1157.
Benson CB, Doubilet PM. Scrotum. General Ultrasound. Mittelstaedt CA.
Churchill-Livingstone, New York, New York; 1992:1139-1142.
Weissleder R, et al. Primer of Diagnostic Imaging, 2nd Edition. Mosby, St. Louis; 1997:840.
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