CLINICAL IMPLICATIONS OF PENILE DOPPLER ULTRASOUND IN ERECTILE DYSFUNCTION: A NARRATIVE REVIEW OF TECHNIQUE, INTERPRETATION, PITFALLS AND EMERGING APPLICATIONS

Abstract

Erectile dysfunction (ED) affects a large and growing proportion of men worldwide, and vasculogenic mechanisms account for most organic cases. Penile Doppler ultrasound (PDUS), which combines pharmacologically induced erection with high-frequency duplex imaging, is the most widely used test of penile haemodynamics, yet its technique, diagnostic thresholds and indications vary considerably between centres. This narrative review, prepared in line with the Scale for the Assessment of Narrative Review Articles (SANRA), synthesises literature from PubMed/MEDLINE, Scopus, Web of Science and Google Scholar (1985–2026) together with current international guidelines. We describe the physiological basis of the Doppler parameters, guideline positions and indications, and a rigidity-based protocol incorporating vasoactive redosing and audiovisual sexual stimulation. A peak systolic velocity (PSV) below 25–30 cm/s indicates arterial insufficiency, whereas an end-diastolic velocity (EDV) of 5 cm/s or more, in the presence of adequate PSV and complete smooth muscle relaxation, indicates corporo-veno-occlusive dysfunction. Incomplete relaxation is the principal source of error: in one prospective series, 47% of outside diagnoses of venous leak proved false on repeat testing, and only about a quarter of published protocols describe redosing. Beyond diagnosis, PDUS predicts response to non-surgical therapy, contributes to cardiovascular risk assessment and surgical planning, and is central to the diagnosis and embolisation of high-flow priapism. Controversies include heterogeneous cut-offs, absent age-adjusted reference ranges and operator dependence. Shear-wave elastography, contrast-enhanced ultrasound and artificial intelligence are promising adjuncts. Standardised, rigidity-based protocols with structured reporting are essential for reliable and comparable PDUS results.