Stiffness of the Central Corpus Cavernosum on Shear-Wave Elastography Is Inversely Correlated with the Penile Rigidity Score in Patients with Erectile Dysfunction

PURPOSE: To perform real-time quantitative measurements of penile rigidity for patients with erectile dysfunction (ED) using shear-wave elastography (SWE). MATERIALS AND METHODS: A total of 92 patients with clinically diagnosed ED filled out an abridged five-item version of the International Index of Erectile Function (IIEF-5) questionnaire and underwent SWE as well as penile color Doppler ultrasound (CDUS) after intracavernosal injection for penile erection. Elasticity measurements were repeated on two sites of the corpus cavernosum (central and peripheral elasticity of corpus cavernosum [ECC]) and the glans penis during the erection phase. Correlations between penile elasticity and rigidity scores or IIEF-5 were evaluated statistically. Penile elasticity was also compared with the ED types based on CDUS. RESULTS: The mean age of all patients was 53.5±13.4 years, and the mean IIEF-5 score was 9.78±5.01. The rigidity score and central ECC value demonstrated a significant correlation (r=−0.272; 95% confidence interval: −0.464 to −0.056; p=0.015). The IIEF-5 score was not significantly correlated with penile elasticity. Vascular ED patients showed significantly higher central ECC values than nonvascular ED patients (p<0.001). At a cut-off value of 8.05 kPa, the central ECC had a specificity of 41.5%, a sensitivity of 84.6%, and an area under the ROC curve of 0.720 with a standard error of 0.059 (p=0.019) for predicting vascular ED. CONCLUSIONS: Quantitatively measuring Young's modulus of the corpus cavernosum using SWE could be an objective technique for assessing penile erectile rigidity and the vascular subtype in patients with ED.