A comparison between portable ultrasound (MIDUS) and nocturnal RigiScan when confirming the diagnosis of vascular organic erectile disorder

Abstract

In recent years, the use of RigiScan and ultrasound to assess erectile dysfunction has fallen from favour. However, in a small minority of specialist cases, where a vascular, neurogenic or psychogenic aetiology requires confirmation, there remains a need for further investigation. To establish if in a preliminary assessment the use of nocturnal RigiScan or male impotence diagnostic ultrasound system (MIDUS) represents best practice as a diagnostic investigation in patients with a history suggestive of vascular organic erectile disorder. Men attending both urological and psychosexual therapy clinics with erectile dysfunction were assessed using a generic assessment schedule. Patients with a history suggestive of vascular erectile disorder were offered the opportunity of dual investigation of their condition. After screening using a provocative RigiScan using visual stimuli that gleaned inconclusive results, patients were offered the chance to enter a study with both nocturnal RigiScan and MIDUS investigation. These were confined for the purposes of this study to RigiScan events, peak systolic flow velocity (PSV) and end-diastolic flow velocity (EDV) from ultrasound examination where an abnormal EDV is defined as in excess of 4.5 cm/s and a normal PSV is variously defined as being greater than 35 cm/s. In all, 38/43 (88%, 95% CI: 76-95%) of men had a nocturnal event exceeding 3 min on the RigiScan investigation. This compares with 17/43 (40%, 95% CI: 26-54%) of men with a normal EDV blood flow of less than 4.5 cm/s (P<0.017) and 32/43 (74%, CI: 60-85%) of men with a normal PSV flow greater than 35 cm/s (NS). Rigiscan and ultrasonography of the cavernosal vessels are of equal usefulness in suspected arterial penile disease although where veno-occlusive disease is suspected, ultrasonography is more specific.