The effect of intracorporeal injection plus genital and audiovisual sexual stimulation versus second injection on penile color Doppler sonography parameters

Purpose: We assessed whether genital and audiovisual sexual stimulation following 1 or 2 intracorporeal injections caused the greatest changes in penile hemodynamics as recorded by color Doppler sonography. Materials and Methods: A total of 50 impotent patients underwent multiphasic color Doppler sonography of the cavernous arteries before and after intracorporeal injection (phase 1), subsequent genital and audiovisual sexual stimulation (phase 2), a second injection (phase 3) and repeat genital and audiovisual sexual stimulation (phase 4). Peak systolic velocity, end diastolic velocity, resistance index and erectile response were studied. Results: Penile erection after injection 1 was upgraded in 41 patients (82%) by genital and audiovisual sexual stimulation. Further upgrading due to injection 2 with stimulation was noted in 11 patients (22%). Among the patients who completed the 4 phases of the test the maximal peak systolic velocity was noted after 1 and 2 injections in 20 (59%) and 14 (41%), respectively. The resistive index was always increased by genital and audiovisual sexual stimulation compared to post-injection values. The maximal resistive index occurred after initial and repeat genital and audiovisual sexual stimulation in 15 (48%) and 16 (52%) patients, respectively. After injection 1 with genital and audiovisual sexual stimulation, impotence was diagnosed as nonvasculogenic in 14 patients (28%), arteriogenic in 9 (18%), venogenic in 17 (34%) or mixed arterio-venogenic in 10 (20%). After injection 2 with stimulation these results were noted in 18 (36%), 9 (18%), 13 (26%) and 10 (20%) patients, respectively. Thus, there were 4 false-positive cases (8%) of venogenic impotence. Conclusions: To study cavernous artery inflow and veno-occlusive function, color Doppler sonography should be performed after injection plus genital and audiovisual sexual stimulation. When the erectile response does not equal the maximal physiological erection reported by the patient, a second injection with stimulation should be given.