Testicular Two-Dimensional Shear Wave Elastography, Peak Systolic Velocity, Volume and Epididymal Thickness: Establishment of Normal Reference Values and Discrimination From Orchitis in Adult Patients Presenting With Acute Scrotal Pain.

Aim: To establish normal testicular stiffness reference values using two-dimensional shear wave elastography (2D-SWE) and together with volume, PSV and epididymal thickness to discriminate from inflammatory pathology, specifically orchitis, in adult patients presenting with acute scrotal symptoms. Materials and Methods: Retrospective analysis of patients referred for scrotal ultrasonography for investigation of scrotal pain or discomfort. Evaluation of 494 testes included B-Mode, colour and pulsed wave (PW) Doppler, testicular volume, peak systolic velocity (PSV) and the median elasticity (SWE). Statistical evaluation was performed to identify stiffness threshold values to rule in normal. Results: In normal testes, the median volume, PSV and SWE were 13.8 mL (10.3-17.2 mL), 6.3 cm/s (4.9-7.7 cm/s) and 2.5 kPa (2.15-2.85 kPa). The right testes were larger (right 14.4 mL, left 13.2 mL, Conclusion: Normal adult testes have a median stiffness of 2.5 kPa. A threshold cut-off median value of 3.6 kPa suggests the diagnosis of an inflammatory testicular pathology such as orchitis, with AUC, accuracy, sensitivity and specificity of 0.922, 0.840, 0.928 and 0.831. Caution is required in the presence of extra-testicular pathology, where there is a wider range of SWE and other parameters.