TIMING OF PENILE COLOR-FLOW DUPLEX ULTRASONOGRAPHY USING A TRIPLE-DRUG MIXTURE

Duplex ultrasonography is an accepted method to assess noninvasively a rterial inflow to the penis. Optimal pharmacological agents as well as timing of the scan and stimulation during the scan continue to be deb ated. In an effort to achieve a more complete smooth muscle relaxation and capture what we perceived was a wide variation in interval to max imum arterial velocity, we revised our duplex protocol in January 1998 . We report on 280 consecutive patients evaluated in this manner. Pati ents received 0.25 or 0.5 cc of a triple drug mixture containing 22.5 mg./cc papaverine, 0.83 mg./cc phentolamine and 8.33 mu g./cc prostagl andin E1. Scans were performed at 0, 5, 15 and 30 minutes after inject ion in all patients. Any patient not having a full erection at 15 minu tes performed private self-stimulation while in the standing position for at least 5 minutes before the 30-minute scan. If we conservatively define normal arterial inflow as a peak Doppler velocity of 25 cm. pe r second or greater in the best artery, only 35% of our patients achie ved this velocity at 5 minutes. Of the remainder 26% and 22% did not r each normal velocity values until 15 and 30 minutes, respectively, aft er the injection. By delaying initial measurements of velocity until 5 minutes, could the highest inflow velocity be missed and patients dia gnosed incorrectly? The group at risk would be those who had good tume scence at 5 minutes and who had presumably already decreased the inflo w velocities. Of the 280 patients 74 (26%) had greater than 10% tumesc ence at 5 minutes. Only 6 of these 74 patients did not reach velocitie s of 25 cm. per second or more in the best artery at some time during their study. In conclusion, our study clearly supports delaying the in itial scan until 5 minutes, since only 6 of our 280 patients (2.1%) ma y have been incorrectly diagnosed. The study also strongly argues for additional scans until 30 minutes and self-stimulation when necessary.