Is there a role of radial rigidity in the evaluation of erectile dysfunction?

RigiScan has been the most widely utilized device for measuring erectile rigidity. However, the use of the RigiScan in the evaluation of erectile dysfunction has questionable because the RigiScan device does not directly determine axial rigidity. The aim of this study is to clarify that radial rigidity measured by RigiScan reflects the intracorporeal pressure and erectile capability efficiently. From January 1998 to May 1999, a total of 23 patients with erectile dysfunction were involved in the study. They were evaluated by RigiScan and duplex ultrasonography after intracorporeal injection of prostaglandin E1. We investigated the relationship between radial rigidity and the resistance index. The results of radial rigidity were also compared with that of the degree of erection. For the entire group, significant correlations were found between radial rigidity and the resistance index (r=0.680, P<0.001 for tip rigidity; r=0.703, P<0.001 for base rigidity). In addition, for 12 patients whose tip rigidity exceeded 60% and for 10 whose base rigidity exceeded 60%, the correlations between radial rigidity and the resistance index remained (r=0.659, P=0.020 for tip rigidity; r=0.759, P=0.011 for base rigidity). Based on the response determined by patients, radial rigidity represented the degree of erection efficiently. Our findings suggest that RigiScan is a useful diagnostic tool. Radial rigidity represents the intracorporeal pressure efficiently and has an acceptable role in the evaluation of erectile dysfunction.