Comparison of Doppler and strain-gauge plethysmography to detect vasculogenic impotence

Doppler penile-pressure determinations to diagnose vasculogenic impotence require an experienced technician, can be time-consuming, yield inconsistent results and require much penile manipulation. Therefore the authors assessed and compared strain-gauge plethysmography as an alternative noninvasive procedure. Sixty-one patients with erectile failure had penile blood pressure determined by Doppler and indium-gallium alloy in Silastic strain-gauge plethysmography. Penile brachial indices were calculated. Strain-gauge results agreed with the Doppler measurements in all but three patients whose indices were found to be normal by Doppler and borderline by strain-gauge plethysmography. The sensitivity, accuracy and specificity of strain-gauge plethysmography were 93%, 95% and 100% respectively. Doppler determinations required an average of 20 minutes to perform, strain-gauge measurements only 4. The authors conclude from this study that strain-gauge plethysmography is a rapid, reliable, accurate method of determining penile blood pressures.