Ultrasound characteristics of extravaginal testicular torsion at different stages of disease progression.

Background: Extravaginal testicular torsion has profound clinical implications in neonates, but its ultrasound characteristics may vary at different disease stages. The purpose of this study was to identify the ultrasound characteristics of neonatal extravaginal testicular torsion and their diagnostic value at different disease stages.

Methods: A retrospective analysis of the clinical and ultrasound examination data of 20 infants aged 1-75 days with surgically and pathologically confirmed unilateral extravaginal testicular torsion (10 right, 10 left) was conducted. The infants were divided into three stages based on the ultrasound characteristics: double-ring effusion, calcification of the tunica vaginalis, and testicular atrophy.

Results: In the double-ring effusion stage, the affected testicles were enlarged with axial abnormalities, with the parenchymal testicular blood flow signal significantly reduced or absent. Twisted paratesticular masses and a "double-ring effusion sign" were visible. In the tunica vaginalis calcification stage, the affected testicles were slightly smaller, with axial abnormalities, absent blood flow signals in the testicular parenchyma, and strong echogenicity of the tunica vaginalis. In the testicular atrophy stage, the affected testicles were markedly smaller, with enhanced echogenicity in the tunica vaginalis and parenchyma, and absent blood flow signal in the testicular parenchyma. The volumes of the affected testicles gradually decreased from the stage of double-ring effusion to that of tunica vaginalis calcification, and then to testicular atrophy (P<0.05).

Conclusions: Neonatal extravaginal testicular torsion at different disease stages has distinct ultrasound features, and color doppler ultrasound plays an important role in the diagnosis and treatment of extravaginal testicular torsion.