Establishing the role of shear wave elastography in differentiating corporal rigidity between vasculogenic versus non-vasculogenic erectile dysfunction patients: a novel diagnostic modality

Abstract

Abstract Background Shear-wave elastography (SWE) is a new modality for evaluation of erectile dysfunction (ED) by assessing the stiffness of tissue. SWE could be an objective tool for assessing penile rigidity during erection and to establish the vascular subtype of ED. In this study we evaluated the SWE values in ED patients in the Indian subpopulation and compare SWE findings between vasculogenic and non-vasculogenic ED patients.Material and Methods 40 patients with clinically diagnosed ED filled out an abridged five-item version of the international index of erectile dysfunction (IIEF-5) questionnaire and underwent SWE as well as pharmacologically induced penile erection (PIPE) test after intracavernosal papaverine injection. SWE values were obtained serially at 5 minutes interval at two locations: Central (cavernosal artery centered circular region) and Peripheral (near the tunica albuginea). SWE values were compared with the ED types based on PIPE test.Results Mean age of patients was 32.48 ± 6.6 years and the median IIEF-5 score was 11(IQR:9–14).IIEF-5 scores had significant inverse correlation with central SWE value in erectile state (p = 0.000, r= -0.536).Median central SWE values were significantly lower in the erectile state as compared to flaccid state in both vascular (8.27 kPa(IQR:6.3–12.5) vs. 23.27 kPa(IQR:15.9–28.6) p = 0.000) and nonvascular(5.50 kPa(IQR:4.4–6.7) vs. 23.85 kPa(IQR:17.8–33.6) p = 0.000) ED patients. Vascular ED patients had significantly higher central SWE value in erectile state than non-vascular ED patients (8.27 KPa (IQR:6.3–12.5) vs. 5.50 KPa (IQR:4.4–6.7) p = 0.001).ROC analysis revealed that the cut off value for central SWE was 5.65 kPa in erectile state with the sensitivity, and specificity for predicting vascular ED being 90.9% and 61.1% respectively. The Area under the curve was 0.816 with a standard error of 0.071 (p = 0.001).Conclusion Central cavernosal shear wave elastography is a good modality to objectively quantify the penile rigidity and can be used to distinguish subtype of erectile dysfunction.