Doppler evaluation of erectile dysfunction

Erectile dysfunction (ED) is the consistent inability to achieve and maintain an erection sufficient for satisfactory sexual activity. Erectile dysfunction affects as many as 30 million men in America, with an increasing prevalence with age. Erectile dysfunction is secondary to organic, psychogenic and combined causes.

The first part of this review article describes the guidelines for evaluation and treatment plans for men with ED. It also describes the normal sonographic anatomy of the penis, sonographic technique for evaluation of ED and the normal phases of erection.

Introduction

National Institutes of Health defines erectile dysfunction (ED) as the consistent inability to achieve and maintain an erection sufficient for satisfactory sexual activity. Erectile dysfunction affects as many as 30 million American men. The disorder is associated with age, with a 39% prevalence at the age of 40 years and a 67% prevalence at the age of 70 years. Massachusetts Male Aging Study reported on 52% of men aged 40–70 years having some degree of erectile difficulty.

Erectile dysfunction includes organic, psychogenic and combined causes. Organic causes are found in 80–90% of patients and include vasculogenic (arterial, cavernosal and mixed), neurogenic, anatomic and endocrine causes. Psychogenic disorders with ED are performance anxiety, depression and inhibited sexual desire.

Guidelines for evaluation and treatment plans for men with ED have usually suggested a stepwise model.

Basic evaluation

Patients with ED undergo a preliminary assessment designed to address significant diseases such as diabetes, coronary artery disease (CAD) and hypertension before starting therapy, so non- or/and least invasive treatments are to be used first. A basic diagnostic evaluation is the first step in ED assessment and is applied for the majority of men, whereas specific diagnostic procedures are implemented in a smaller subset of patients. The basic evaluation is often commenced by the primary care physicians. Occasionally, a number of patients are diagnosed and treated by cardiologists, neurologists, endocrinologists and psychiatrists, who treat ED as a comorbidity of an underlying disease.

Basic evaluation includes thorough medical, sexual and psycho-sexual history, physical examination and limited laboratory assessment. Radiological imaging in the field of ED has diminished in importance over the past 10 years with the introduction of new effective oral therapies and the recognition that surgical treatment of both penile venous leak and arterial insufficiency have poor long-term clinical outcomes. The introduction of phosphodiesterase-5 (PDE5) inhibitors has revolutionized the therapeutics of ED and radically changed the way in which men with ED are assessed and investigated. Documentation of a good quality erection in response to a PDE5-inhibiting drug confirms grossly adequate arterial flow and patent veno-occlusive mechanisms. However, color Doppler ultrasound continues to have a role in the evaluation of specific patients with ED and has an increasing role in the detection of silent CAD in men presenting with ED.