Is There a Point to Performing a Penile Duplex Ultrasound?

Abstract

Introduction: Specialized diagnostic evaluation of erectile dysfunction (ED) may require an intracavernous injection test (IIT) or penile duplex ultrasound (PDU).

Aim: Our primary objective was to compare the prognostic value of IIT and PDU for treatment efficacy and patient satisfaction with first-line sildenafil citrate.

Methods: After 200 patients were screened, a total of 77 patients with ED had a standardized PDU by a blinded third party, and peak systolic velocity (PSV), end diastolic flow (EDF), and resistive index (RI) in timely intervals were recorded. The erection hardness score (EHS) was used to score erection rigidity during the test and was also noted. Patients also completed a briefed International Index of Erectile Function (IIEF-5) questionnaire and were started on open-label 100 mg sildenafil citrate at baseline. The IIEF-5 and erectile dysfunction inventory of treatment satisfaction (EDITS) questionnaires were repeated and completed at 6 months' follow-up. Improvement, cure, and satisfaction were defined as an increase of 4 points in IIEF-5 with an IIEF-5 score higher than 21 points and EDITS score higher than 50, respectively. Receiver operating characteristic curves were drawn and the area under the curve (AUC) was calculated and compared.

Main outcome measure: EHS did not have a different or larger AUC than PSV, EDF, and RI for improvement, cure, and satisfaction with sildenafil citrate.

Results: The patient's mean age was 58.76 ± 10.27 years and almost half of the patients had moderate ED according to the IIEF-5 (42.8%). Improvement, cure, and satisfaction were high among participants (77.9%, 64.9%, and 67.5%, respectively). The erection rigidity EHS also showed an excellent-to-good ability to predict improvement, cure, and patient satisfaction (AUC = 0.921, 0.873, and 0.898, respectively) with sildenafil citrate.

Clinical implications: There is no point in performing more than an IIT when a specialized diagnostic evaluation is required for diagnostic or medico-legal reasons because PDU is time-consuming and requires both hardware and ultrasound skills with no added prognostic value.

Strengths and limitations: This is the first prospective study to directly compare IIT with PDU, and validated disease-specific questionnaires were used to assess both clinical efficacy and satisfaction. Moreover, the PDU was performed by a blinded third party. However, this was a single-center study and the population included was small.

Conclusion: PDU parameters add no prognostic value to determining erection rigidity during a standard IIT. Erection rigidity during IIT, as assessed with the EHS, suffices as a prognostic tool. Morgado A, Diniz P, Silva CM. Is There a Point to Performing a Penile Duplex Ultrasound? J Sex Med 2019;16:1574-1580.

Keywords: Erectile Dysfunction; Erection Hardness Score; Intracavernous Injection Test; Penile Doppler Ultrasound; Prognostic; Satisfaction.