Objectives. A prospective study was performed comparing duplex ultrasonography (DU) and ultrasonic velocitometry (UV), using a new fixed-angle device, in assessing penile arterial hemodynamics. Cavernous arterial peak systolic and end-diastolic flow velocities were measured. Methods. Twenty-four consecutive patients (mean age 47 years) underwent DU (Ultramark 9 HDI System) and UV (Knoll/MIDUS system) at the same setting by the same technician. After preinjection scanning, all patients received 60 mg of papaverine intracavernosally. Repeat scanning was performed at 5, 10, 15, and 20 minutes. Results. The statistical significance between the two techniques was assessed by examining the correlation. For all patients (n = 24) and all velocity determinations in all patients (n = 554), the equation for the linear regression line is y = 0.952x + 1.453, r = 0.91 (r(2) = 0.82) and P<0.05. Conclusions. UV is as accurate as DU in measuring peak flow velocities of the cavernous artery. This new fixed-angle device is capable of identifying a vessel without real time imaging. UV is a safe, office-based procedure and scanning is less operator-dependent and easier to learn. (C) 1998, Elsevier Science Inc. All rights reserved.