Value of power Doppler sonography in the investigation of erectile dysfunction

Objectives: The poor sensitivity of conventional color-coded Doppler sonogr aphy (CCD) for low-flow signals limits its use for investigating patients w ith erectile dysfunction. Power Doppler sonography (PD) has recently been d escribed for enhanced visualization of the microcirculation. Aim of this st udy was to determine the value of PD to demonstrate penile vascular pathoph ysiology as compared with conventional techniques. Methods: 33 consecutive men with erectile dysfunction were investigated using the standard workup w ith conventional CCD and cavernosography before and after prostaglandin E-1 intracavernosal injection. Patients were subdivided into an arteriogenic, a venogenic, or a psychogenic group according to findings in the standard d iagnostic workup. PD was used in addition to the standard protocol to demon strate microcirculation, arterial blood flow, and venous leakage. The accur acy of the diagnosis obtained by PD and response to intracavernosal injecti on was compared with the clinical outcome in these groups at 6 months. Resu lts: PD was found to be superior to CCD in visualizing cavernosal microcirc ulation. In addition, arterial flow at basal peak systolic velocity was dem onstrated in all patients with PD, whereas a signal sufficient for evaluati on was obtained with CCD in only 69.7% (23/33). No significant difference i n the maximal peak systolic velocity was noted using either PD or CCD. The positive predictive value of PD for venous leakage was poor (60%) when comp ared with cavernosography. PD used in conjunction with the response to intr acavernosal injection was found to reliably predict the clinical outcome in the arteriogenic (p = 0.0007), the venogenic (p = 0.005), and the psychoge nic group (p = 0.0002). Conclusions: Our data indicate that PD improves the evaluation of penile microcirculation and arterial function, but fails to reliably demonstrate venous leakage alone. Nevertheless, in most patients c avernosography could have been avoided by the aid of PD, since the underlyi ng pathology can be calculated at a high predictive value without the need of further invasive tests. Therefore, with the aid of PD, the morbidity for patients being investigated for erectile dysfunction can be significantly reduced.