RESUMEN
Intracavernosal injection of a vasodilating agent, followed by color Doppler ultrasonography of the penis, is used to diagnose vascular impotence. The vasodilating agent is usually injected into one of the corpora cavernosa and the peak systolic velocity (PSV) of the cavernosal arteries is measured on both sides, presuming that the connection between the two cavernosal bodies will distribute the drug uniformly on both sides and will consequently affect the cavernosal arteries and sinusoids equally. According to our experience, the PSV of the injection side is higher than that of the contralateral side. This difference could affect the results of the evaluation. In this study, our objective was to compare the results of both-side injections with those of one-side injection. A total number of 60 patients with a normal Doppler study of the penis were enrolled in the study and were randomly divided into three groups. In the first and second group, 60 mg papaverine was injected into the right and left corpus cavernosa each. In the third group, half of the dose was injected into each side. The mean maximum PSV was measured and compared in each group. The mean maximum PSV in the group with the right-side injection was 47.7+/-10.8 and 40.3+/-9.2 on the right and left side, respectively. The mean maximum PSV in the group with the left side injection was 44.4+/-7.1 and 51.4+/-7.1 on the right and the left side, respectively. The mean maximum PSV in the group with bilateral injection was 47+/-9.9 on the right side and 46.7+/-10.7 on the left side. In the first two groups, there was significant difference between the mean maximum PSV of the right and left cavernosal arteries, but in the third group, there was no significant difference between the mean maximum PSV of both side cavernosal arteries. Injecting papaverine in only one corpus cavernosum, despite a perfect postinjection manipulation of the penis, will affect the sinusoids and cavernosal artery at the same side of the injection more than the contralateral side. This results in a higher increase in the blood flow and PSV on that side and results in an artifactual difference between the velocity of the right and left side, which could ultimately exaggerate or mask the actual difference between the two sides. Dividing the total dose of the vasodilating agent and injecting half of the dose into each corpus cavernosum separately prevents artifactual difference between blood flow and velocity on the right and left side.
