Ultrasound for the Diagnosis of Testicular Torsion: A Systematic Review and Meta-analysis of Diagnostic Accuracy

BACKGROUND AND OBJECTIVE: Uncertainty regarding the diagnostic accuracy of ultrasound for testicular torsion (TT) and a lack of high-level evidence to inform international guidelines have led to significant global variation in its use. The objective of this study was to assess the diagnostic accuracy of ultrasound for TT. METHODS: This systematic review was undertaken in accordance with the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy. A comprehensive electronic search strategy was applied up to January 4, 2024. Colour Doppler sonography (CDS) was the primary index test, with surgical scrotal exploration or clinical follow-up as the reference standard. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was used to assess the risk of bias and applicability. Meta-analyses were performed using bivariate models. KEY FINDINGS AND LIMITATIONS: Sixty-three studies met the inclusion criteria; 54 (85.7%) assessed CDS, and the others assessed spectral doppler sonography (n = 6), contrast enhanced ultrasound (n = 1), or an alternative combination of ultrasound technologies (n = 2). The summary sensitivity (95% confidence interval [CI]) and specificity (95% CI) of CDS for the diagnosis of TT were 95.3% (91.4-97.5) and 98.3% (96.2-99.3), respectively (42 studies, 4422 participants). Patient selection (related to the risk of bias and applicability concern) was identified as the domain of the greatest methodological concern on QUADAS-2 assessment. CONCLUSIONS AND CLINICAL IMPLICATIONS: CDS has high diagnostic accuracy for TT. The ideal patient pathway for suspected TT should integrate timely access to ultrasound alongside clinical assessment, with careful patient counselling.