New concept parameters of RigiScan in differentiation of vascular erectile dysfunction: is it a useful test?

The aim of this study is to investigate the value of new nocturnal penile tumescence recording parameters, such as tumescence activity unit and rigidity activity unit values, total erection number and erection times, in differentiating between psychogenic erectile dysfunction and organic erectile dysfunction. We also aimed to determine the role of these parameters in differentiating arterial erectile dysfunction from veno-occlusive dysfunction.

Eighty-seven consecutive patients were allocated into three groups as psychogenic, arterial and venous erectile dysfunction after investigations. Nocturnal penile tumescence recording parameters between psychogenic and vascular erectile dysfunction and arterial and veno-occlusive dysfunction were compared. Mann-Whitney U-test, Pearson's chi2 test and correlation coefficient tests were used for statistical analysis.

Depending on intracavernous injection, penile Doppler ultrasonography and cavernosometry tests, 37 patients (43%) had psychogenic impotence while 50 (57%) had organic pathologies. Of the 50 patients diagnosed with vascular impotence, 29 (48%) had arterial failure and 21 (42%) had veno-occlusive dysfunction. Nocturnal penile tumescence recording revealed psychogenic erectile dysfunction in 34 patients (39%) and vascular erectile dysfunction in 53 patients (61%). Nocturnal penile tumescence recording has been regarded as the gold standard and, in our series, it showed 90.6% sensitivity and 88.2% specificity in differentiating the cause of erectile dysfunction. Values of rigidity activity unit and tumescence activity unit were significantly higher in patients with psychogenic impotence (P < 0.001), when compared with vascular impotence. In patients with a vascular cause, no difference was found between arterial failure and veno-occlusive dysfunction with regard to tip tumescence activity unit, base tumescence activity unit, tip rigidity activity unit, base rigidity activity unit and erection time (P > 0.001). However, patients with arterial failure had less erection than patients with veno-occlusive dysfunction (P < 0.001).

New recording parameters of nocturnal penile tumescence can differentiate organic and psychogenic erectile dysfunction more precisely. However, these recording parameters cannot distinguish subgroups with a vascular cause of erectile dysfunction.