What does duplex ultrasound add to sexual history, nocturnal penile tumescence and intracavernosal injection of smooth muscle relaxant, in the diagnosis of erectile dysfunction?

A consecutive series of 52 men presenting with erectile dysfunction were assessed with (i) standardized sexual history, (ii) nocturnal penile tumescence and rigidity monitoring (NPTR), (iii) Rigiscan assessment of response to intracavernosal papaverine or prostaglandin injection (ICI), and (iv) duplex ultrasonography. Subjects were categorized into 'organic', 'psychogenic' or 'uncertain' on the basis of the first three assessments, and duplex variables compared across the diagnostic groups. Maximum increase in arterial diameter and maximum systolic flow following ICI did not discriminate between groups. End diastolic flow and resistance index at 15 min following ICI was significantly higher in the organic than the psychogenic groups. None of the duplex variables helped to diagnose further those in the 'uncertain' categories. The diagnostic value of the duplex is probably substantially reduced by psychological inhibition of the response to ICI. Duplex ultrasound scanning does not appear to be a helpful initial diagnostic method for erectile dysfunction, but may have value in further identifying the aetiology in 'organic' cases, especially venous leakage. NPTR appears to be the best single diagnostic procedure. Methods of identifying the occurrence of psychological inhibition and 'false negative' results with ICI will enhance the diagnostic value of duplex ultrasonography.