The penile duplex ultrasound: How and when to perform it?

Abstract

Background: Because it is a superficial structure, the penis is ideally suited to ultrasound imaging. A number of disease processes, including Peyronie's disease, penile fractures and tumors, are clearly visualized with ultrasound. Baseline and dynamic assessment of cavernosal arterial changes after pharmaco-stimulation with alprostadil allows standardized diagnosis of arterial and venogenic causes of erectile dysfunction (ED).Objective: To illustrate how to correctly perform flaccid and dynamic penile duplex ultrasound (D-PDU) and in which patients to recommend it.Materials/Methods: An extensive search of the literature was carried out on Pubmed with the insertion of the following Medical Subjects Headings (MeSH) terms and keywords "penile color Doppler ultrasound" "peak systolic velocity" "end-diastolic velocity", "acceleration time", "resistance index".Evidence: In our experience, arterial erectile dysfunction is identified after standardized intracavernous injection (ICI) of alprostadil (10 mcg) when values of peak systolic velocity (PSV) are <35 cm/s and, in the most severe forms, for values <25 cm/s.Arterial insufficiency can also be identified by increased acceleration time (AT) values (>110 ms) and/or by a lack of visualization of helicine arteries at power Doppler mode along with incomplete achievement of penile rigidity. The veno-occlusive incompetence is determined when end-diastolic velocity (EDV) values are >4.5-5 cm/s or in the case of resistance index (RI) values <0.75. The assessment of additional surrogate markers of endothelial dysfunction, that is, intima-media thickness, mean platelet volume (MPV), endothelial progenitor cells (EPC), endothelial cell specific molecule-1(endocan) are also useful in assessing the patient's cardiovascular risk but are still considered investigational in the interpretation of D-PDU results.Conclusion: D-PDU scan after ICI with vasoactive drugs is a safe procedure and represents the gold standard for the diagnostics of penile pathologies and should be performed in men with ED not responding to oral conventional therapies and/or in those requiring accurate stratification of cardiovascular risk.

Long-term high-dose l-arginine supplementation in patients with vasculogenic erectile dysfunction: a multicentre, double-blind, randomized, placebo-controlled clinical trial

“…The current study also addressed ED by PDU, a second-level diagnostic tool with respect to ED diagnosis, by providing further objective information concerning the penile erectile function, and particularly the vascular status, compared to clinical information deriving from first-level diagnostic tools, such as anamnesis and standardized questionnaires [ 32 – 34 ]. Moreover, in the current study, dynamic PDU was preferred over basal PDU for several orders of reasons: dynamic PDU is more currently used, compared to basal PDU, both in the clinical practice and in clinical trials, for the completion of ED diagnosis and the assessment of erectile response to pharmacological treatments [ 35 ]; dynamic PDU is considered by dedicated guidelines as the gold standard for the diagnosis of ED of vasculogenic etiology, by allowing to objectively quantify penile vascular status and identify potential vascular abnormalities, before and during an erection, therefore representing the best candidate tool for the purposes of the current study, focused on vasculogenic ED [ 35 , 36 ]. Furthermore, dynamic PDU has a crucial role in the differential diagnosis between psychogenic and the most common form of organic ED, namely vasculogenic ED, in patients of different ages [ 35 ]; in particular, dynamic PDU has been reported to have a more specific diagnostic value for recognizing or excluding vasculogenic ED in the setting of constitutive severe anxiety-affected young patients, which despite a pathological PSV in flaccid state due to an exaggerated sympathetic tone, might reach a normal PSV value after pharmacologically induced erection, therefore overcoming a potential bias of basal PDU procedure [ 35 – 37 ].…”

“…Moreover, in the current study, dynamic PDU was preferred over basal PDU for several orders of reasons: dynamic PDU is more currently used, compared to basal PDU, both in the clinical practice and in clinical trials, for the completion of ED diagnosis and the assessment of erectile response to pharmacological treatments [ 35 ]; dynamic PDU is considered by dedicated guidelines as the gold standard for the diagnosis of ED of vasculogenic etiology, by allowing to objectively quantify penile vascular status and identify potential vascular abnormalities, before and during an erection, therefore representing the best candidate tool for the purposes of the current study, focused on vasculogenic ED [ 35 , 36 ]. Furthermore, dynamic PDU has a crucial role in the differential diagnosis between psychogenic and the most common form of organic ED, namely vasculogenic ED, in patients of different ages [ 35 ]; in particular, dynamic PDU has been reported to have a more specific diagnostic value for recognizing or excluding vasculogenic ED in the setting of constitutive severe anxiety-affected young patients, which despite a pathological PSV in flaccid state due to an exaggerated sympathetic tone, might reach a normal PSV value after pharmacologically induced erection, therefore overcoming a potential bias of basal PDU procedure [ 35 – 37 ]. Moreover, in patients with ED, particularly in middle-aged and elderly patients, dynamic PDU may also provide a predictive response for the potential effectiveness of the vasodilative drugs used for ED, as demonstrated by the negative correlation between the severity of penile vascular damage and the clinical response to treatment with PDE5i [ 38 ].…”

“…Moreover, in patients with ED, particularly in middle-aged and elderly patients, dynamic PDU may also provide a predictive response for the potential effectiveness of the vasodilative drugs used for ED, as demonstrated by the negative correlation between the severity of penile vascular damage and the clinical response to treatment with PDE5i [ 38 ]. Lastly, it is important to remark that ED could represent an early predictor of CV events and the diagnosis of vasculogenic ED at PDU, and particularly at dynamic PDU as the gold standard diagnostic tool, both in patients with or without additional CV risk factors and/or comorbidities, can help to recognize eventual arterial diseases in biggest distal vessels [ 35 , 39 – 41 ]. Nevertheless, dynamic PDU is a minimally invasive diagnostic test and might be associated to adverse effects such as mild penile pain and, rarely, in about 5% of cases, priapism, which is mostly spontaneously reversible, and very rarely reversible after prompt therapeutic intervention.…”

From organ injury to disability: a proposed model for 5-alpha reductase inhibitor syndrome

“…Any imaging that can capture tissue abnormalities in the penis would be relevant. 122,123 Diagnostic techniques for cognate diseases such as stroke and microvasculopathies might be explored (Table 4, column 3).…”

A Novel Method to Quantify Penile Arterial Blood Supply Using Shear Wave Elastography During Penile Duplex Ultrasound in Men with Erectile Dysfunction

“…Of course, the PSV was also the most important parameter of PDU to diagnose arterial ED [ 16 ]. If ED patients have PSV <30 cm/s, arterial ED is diagnosed, meaning that the ED was mainly caused by insufficient penile artery blood supply when patients engage in sexual intercourse [ 17 ]. However, several shortcomings limited the PDU application for ED patients, including checking time, optimal cut-off values, and the variability among different radiologists [ 18 ].…”