THE EFFECT OF INTRACORPOREAL INJECTION PLUS GENITAL AND AUDIOVISUAL SEXUAL STIMULATION VERSUS SECOND INJECTION ON PENILE COLOR DOPPLER SONOGRAPHY PARAMETERS FRANCESCO MONTORSI, GIORGIO GUAZZONI, LUIGI BARBIERI, LAURA GALLI, PATRIZIO RIGATTI, GIULIANO PIZZINI AND ALBERT0 MIANI Front the Instttute of H u m a n Anatomy and Drpartnlvrits of Cindogy and Medical Statistics. C1niversit.v of Milan School Scientific Institute. H . Son Raffaelr, Milan. Italt.

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ABSTRACT

Purpose: We assessed whether genital a n d audiovisual sexual stimulation following 1 or 2 intracorporeal injections caused the greatest changes i n penile hemodynamics as recorded by color Doppler sonography. Materials a n d Methods: A total of 50 impotent patients underwent multiphasic color Doppler sonography of t h e cavernous arteries before and after intracorporeal injection ( p h a s e 1), subseq u e n t genital a n d audiovisual sexual stimulation (phase 21, a second injection (phase 3) a n d repeat genital and audiovisual sexual stimulation (phase 4). Peak systolic velocity, end diastolic velocity, resistance index a n d erectile response were studied. Results: Penile erection after injection 1 was upgraded in 41 patients (82%)by genital a n d audiovisual sexual stimulation. F u r t h e r upgrading d u e t o injection 2 with stimulation w a s noted in 11 patients (22%). Among t h e 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 a n d audiovisual sexual stimulation compared to post-injection values. T h e maximal resistive index occurred after initial and r e p e a t genital a n d audiovisual sexual stimulation in 15 (48%) and 16 (52%)patients, respectively. After injection 1with genital and audiovisual sexual stimulation, impotence w a s diagnosed as nonvasculogenic in 14 patients (28%'),arteriogenic in 9 (18921, venogenic in 1 7 (34%)or mixed arteriovenogenic 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 a n d 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. KEY WORDS:penile erection, impotence, audio-visual aids, injections, ultrasonography Penile erection is a complex psycho-neurovascular phenomenon involving not only the coordination of 3 main hemodynamic events (increased arterial flow, sinusoidal smooth muscle relaxation and decreased venous drainage) but also the interaction of nerves, neurotransmitters, striated and smooth muscle, and tunica albuginea.' Any alteration in 1 of these components may lead to erectile dysfunction and, in particular, abnormalities of penile hemodynamics are currently considered the most frequent organic Thus, evaluation of penile circulation is usually considered of paramount importance in the initial assessment of most patients with erectile dysfunction.3 Color Doppler sonography has been increasingly gaining a role in the diagnosis of cavernous artery function, while the role in the assessment of the corporeal veno-occlusive mechanism has not yet been unanimously accepted.4-11 Recently, it has been recognized that to study the venoocclusive mechanism of the corpora cavernosa precisely, total relaxation of the corporeal smooth muscle must first be achieved. I2. Unfortunately, the simple intracavernous injection of 1 or more vasoactive drugs usually used during penile color Doppler sonography is only able to induce maximal smooth muscle relaxation in a minority of patients. Accepted for publication August 18, 1995.

However, i t has been clearly demonstrated that adjunctive genital and audiovisual sexual stimulation can significantly increase the erectile response after intracavernous injection.14.1s In addition, we recently demonstrated that the overall accuracy of color Doppler sonography is significantly enhanced by measuring the cavernous artery flowmetric parameters not only after intracavernous injection but also after a phase of genital and audiovisual sexual stimulation."' During pharmaco-cavernosometry, the gold standard procedure for assessment of the corporeal veno-occlusive mechanism, maximal smooth muscle relaxation is achieved only in the presence of a linear relationship between intracavernous pressure and flow, which is often not obtained until multiple injections of vasoactive drugs have been performed.'-'-" Therefore, we assessed the impact of a second intracorporeal injection of vasoactive substances on cavernous artery parameters as measured by color Doppler sonography and compared the results to those obtained after a single injection with genital and audiovisual sexual stimulation. MATERIALS AND METHODS

From September to December 1994 w e studied 50 consecutive impotent patients. In each patient a detailed sexual history was obtained with a search for the main risk factors

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for impotence. Each patient also underwent physical exami- was stopped if there was a rigid erection, while the other nation and laboratory tests (serum glucose, glycosylated he- patients were asked to compare the erection with that w u moglobin, cholesterol, triglycerides and hormonal profile). ally obtained during sexual activity and then they received Color Doppler sonography of the cavernous arteries was per- another injection with the same vasoactive mixture. Cavernformed with a specifically dedicated system equipped with a ous artery flowmetric parameters were measured after 5,lO real-time electronic sector transducer with an imaging fre- and 15 minutes, and erectile response was graded again. quency of 7.5 MHz. and pulsed Doppler unit with a frequency Genital and audiovisual sexual stimulation with color of 5 MHz. During color Doppler sonography the length of the Doppler sonography and clinical measurement of the erectile sample volume was maintained at 2 mm. in all cases. The test was performed by 1 of us (F. M.)in a room specifically response were repeated. The 4 phases of the test are summarized in the figure. prepared to relax the patient. During the various phases of Doppler recording, the greatest With the patient supine the sonographic probe was placed on the lateral sides of the penis at the level of the penoscrotal value of peak systolic velocity was considered to indicate junction. A preliminary ultrasonographic scan of the corpora cavernous artery idlow, while the greatest value of resistive cavernosa with the penis flaccid was done to visualize possi- index and the lowest value of end diastolic velocity were uaed ble areas of fibrosis or scarring. The diameter of the cavern- to determine the status of the corporeal veno-occlusive mechous arteries was measured at the penoscrotal junction by anism. Cavernous artery inflow was considered normal when locating the specific electronic calipers on the inner aspect of peak systolic velocity was greater than 35 cm. per second, the arterial wall. Then 0.1 ml. of a vasoactive mixture com- while the corporeal veno-occlusive mechanism was considposed of 12.1 mg./ml. papaverine, 10.1 pg./ml. prostaglandin ered normal with a resistive index of greater than 0.9 and a n E l , 1.01mg./ml. phentolamine and 0.15 mg./ml. atropine was end diastolic velocity of less than 5 cm. per second. The patients were observed for at least 60 minutes after injected into the left corpus cavernosum and the injection site was compressed for 3 minutes. Our vasoactive mixture was the end of the examination. In cases of a persistent rigid composed of drugs eliciting pharmacological effects through erection 20 to 40 pg. epinephrine were injected into either different mechanisms of action, possibly causing a synergism corpus cavernosum to achieve flaccidity. The patient was able to potentiate the overall vasoactive effect. Atropine was contacted by telephone within 24 hours to verify any possible added to the well known association of papaverine, phentol- persistent erection. amine and prostaglandin E l according to the preliminary Statistical analysis of results was based on the matched observations of Virag et a1.18-"0 I t is known that atropine signed rank test, Pearson's chi-square test and McNemar's sulfate at low doses (lo-' M.) blocks muscarinic receptors, test of symmetry. thereby diminishing cholinergic inhibition of the adrenergic and cholinergic excitation of the nonadrenergic, noncholinergic neuroeffector systems controlling neurogenic corporeal smooth muscle relaxation. However, at large pharmacologiPHASE 1 cal doses (lo-" M.)atropine causes release of the endotheFirst intracorporeal vasoactive injection lium derived relaxing factor, which has recently been identi- Doppler recordings at 5, 10. 15 min fied as a neurotransmitter involved in penile erection.Z* To - Grading of erection our knowledge the mixture volume chosen for stimulation during color Doppler sonography was the largest volume Rigid and sustained erection used by a patient diagnosed with purely psychogenic erectile End of test dysfunction and undergoing our pharmacological erection program.2!!.23 After injection, the diameter of the cavernous arteries was PHASE 2 measured again. Color Doppler recording of the cavernous First genital + audio visual sexual stimulation for 10 min arteries was performed a t the penoscrotal junction along an - Doppler recordings arterial segment corresponding to a Doppler angle of 50 - Grading of erection degrees to obtain data comparable among different patients. The right and left cavernous arteries were evaluated 3 minutes after injection and then at 5, 10 and 15 minutes. Peak Rigid and sustained erection systolic velocity, end diastolic velocity and resistance index End of test were recorded on pre-programmed software specific to our color Doppler system. Resistive index was calculated accordPHASE 3 ing to the formula: resistance index = peak systolic velocity Second intracorporeal vasoactive injection - end diastolic velocity/peak systolic velocity. At the end of this phase, the patient was asked to stand, and the erection - Doppler recordings at 5, 10, I5 min was graded as 1-rigid, 2-more than 50% tumescence, - Grading of erection 3-less than 50% tumescence and 4-flaccid. Patients with rigid erections and normal color Doppler sonography parameters were considered to have nonvasculogenic impotence Rigid and sustained erection and did not continue the study. The remaining patients were End of test then left alone in the room, audiovisual sexual stimulation PHASE 4 was started (showing the same segment of an erotic video to Second genital + audio visual sexual stimulation for 10 min. each subject) and the patient was encouraged to masturbate (without ejaculation) for 10 minutes. Erection was assessed - Doppler recordings and graded as previously described, and changes due to au- Grading of erection diovisual sexual and manual stimulation were recorded. The erectile responses were graded by 1of us (L.B.) who did not participate in the Doppler examination and was not aware END OF TEST of the flowmetric results. Color Doppler sonography of the Structure and timing of color Doppler sonography of cavernous cavernous arteries was repeated and the aforementioned flowmetric parameters were measured. At this p i n t the test arteries.

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When a rigid erection was obtained and Doppler data indicated normal penile hemodynamics t h e test was concluded before the end of the scheduled 4 phases: after injection 1 (phase 1) in 3 patients ( 6 V )and after the initial genital and audiovisual sexual stimulation (phase 2 ) in 10 (20%). All patients who received 2 injections completed all 4 phases of the study 1 that is after 2 episodes of genital and audiovisual sexual stimulation J, Peak systolic velocity did not demonstrate any statistically significant modification throughout t h e different phases of the study (mean 40.4 2 2.1 cni. per second [standard deviation] for phase 1, 37.6 ? 1.8 cm. per second for phase 2, 37.8 ? 2.5 cm. per second for phase 3 and 36.7 ? 2.2 cm. per second for phase 4. p >0.05). End diastolic velocity showed a statistically significant decrease from phases 1 to 2 ( 10.1 ? 0.6 versus 5.0 cm. per second. p <0.0001)a n d from phases 3 to 4 (9.3 2 0.5 versus 5.4 z 0.6 cm. per second, p <0.0001), t h a t is after 2 sessions of genital and audiovisual sexual stimulation. Thus, a significant effect of genital and audiovisual sexual stimulation was demonstrated for this parameter. When phases 2 and 4 were compared no significant difference was noted ( p = 0.441. In other words, injection 2 with genital and audiovisual sexual stimulation, compared with t h e first set of stimulations, did not induce a significant increase in relaxation of the corporeal smooth muscle and subsequent better activation of the veno-occlusive mechanism in the majority of patients. As expected, resistive index showed a completely opposite pattern to that observed with end diastolic velocity. Resistive index increased significantly from phases 1 to 2 (0.73 2 0.19 versus 0.85 2 0.19, p <0.0001) and from phases 3 to 4 (0.71 2 0.23 versus 0.81 ? 0.26, p <0.0001). As with end diastolic velocity, when phases 2 and 4 were compared, no significant difference was found ( p = 0.32).When erectile response was evaluated, a significant amelioration ( p <0.0001) was noted after adjunctive genital and audiovisual sexual stimulation (phases 2 and 4 ) compared to t h e effect of injection only (phases 1 and 3). Interestingly, significantly better erections ( p <0.01) were noted at the end of injection 2 compared to injection 1, which might mean t h a t the cavernous arteries may not show a maximal response to 1 intracavernous administration of vasoactive substances due to, for instance, a massive presence of intracorporeal adrenergic substances induced by anxiety related to the test. When the diagnoses established at the end of each phase were compared, it became clear that t h e serial administration of intracavernous drugs and genital and audiovisual sexual stimulation was able to enhance the diagnostic potential of the test significantly. The table shows the different diagnoses according to results obtained after the 4 phases of t h e test. #en the diagnosis of nonvasculogenic impotence was specifically considered, the chi-square test demonstrated a statistically significant difference throughout all 4 test phases (chi-square 11.772, p = 0.010). When the diagnoses obtained after phases 2 and 4 were compared to assess the impact of injection 2 with genital and audiovisual sexual stimulation a statistical difference was demonstrated ( p < 0.05). Namely, the number of patients with the diagnosis of venogenic impotence decreased from 17 (34%)to 13 126%). In Dingnosrs in .50 p n t i r n f s estahlishrd after each phase according to clinirnl responsr and color Doppler data ~-

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these 4 patients the erection obtained after phase 2 (injection 1 plus genital and audiovisual sexual stimulation) h a d been reported a s less t h a n that usually obtained during sexual activity, t h u s implying incomplete relaxation of the corporeal smooth muscle. Of t h e 13 patients with a final diagnosis of venogenic impotence 3 (23%t reported t h a t natural erections were better t h a n those obtained after phase 4 of t h e study 1 injection 2 plus genital and audiovisual sexual stimulation). These patients were studied further by polysomnographic recording of nocturnal erections using tumescence and rigidity monitoring with measurements of buckling force a n d Rigiscan* data. In 2 cases impotence was organic, while 1 patient had 1 rigid erection (axial rigidity 1000 gm., radial rigidity 90%) for 18 minutes and the impotence was then considered nonorganic. Two patients (4%) had a r i s d erection after phase 2 with Doppler evidence of abnormal cavernous artery inflow. On t h e contrary, 9 of 19 patients ( 4 7 4 ) with mixed arteriovenogenic impotence after phase 1 (injection 11showed some improvement in peak systolic velocity values after genital and audiovisual sexual stimulation (phase 2) but they still had cavernous artery occlusive disease. In patients with normal cavernous artery function after either injection 1 or 2 subsequent genital and audiovisual sexual stimulation rarely caused a further increase i n peak systolic velocity values. DISCUSSION

Abnormalities of penile hemodynamics a r e the main cause of erectile dysfunction and their precise recognition during diagnosis may be of dramatic value when choosing the optimal therapy. Color Doppler sonography has increasingly gained a role in t h e vascular assessment of penile erectile dysfunction and is almost unanimously considered t h e gold standard technique to evaluate cavernous artery function i n a minimally invasive manner.4 Several investigators recently explored t h e potential use of color Doppler sonography to evaluate the veno-occlusive mechanism of the corpora cavernosa by comparing the results obtained with standard pharmaco-cavernosometry.5-9~l6 Measurement of end diastolic velocity and resistive index of the cavernous arteries, together with flow velocity along the deep dorsal vein, had been initially indicated as potential indexes of veno-occlusive mechanism function, although some investigators have questioned this finding."11 It later became apparent t h a t to study precisely t h e corporeal veno-occlusive mechanism, complete relaxation of t h e smooth muscle cells of the corpora cavernosa h a d to be obtained first as demonstrated in t h e animal model by Saenz de Tejada e t al, who initially showed the need to infuse multiple doses of vasoactive substances to obtain a linear relationship between intracorporeal pressures and flow-to-maintain during pharmaco-cavernosometry.l? The linearity of the pressureflow relationship indicated complete smooth muscle relaxation. The clinical implication of this pioneer study was a necessary modification of the technique of pharmaco-cavernosometry to avoid false-positive diagnoses of venogenic impotence due to incomplete corporeal smooth muscle relaxation during the test.3 Because in all of the previously reported studies assessing the role of color Doppler sonography in the evaluation of the corporeal veno-occlusive mechanism the test was performed after a single intracorporeal vasoactive injection, they all shared the same bias, t h a t is the degree of corporeal smooth muscle relaxation was always considered maximal in the absence of any actual objective quantification:*-''.l'> In addition, it h a s been clearly shown t h a t adjunctive genital or audiovisual sexual stimulation is able to potentiate t h e erectile response after an intracorporeal vasoactive injection in

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most patients.'* -I6 This improvement in erectile response mechanism. To date, in our experience some patients were has been suggested to be due to the release of several neu- given 4 subsequent injections with genital and audiovisual rotransmitters causing a better activation of the process of sexual stimulation to achieve maximal erection. However, corporeal smooth muscle relaxation. the majority of our patients would need 1 or 2 sets of injection Thus, a t our institute we became interested in assessing with genital and audiovisual sexual stimulation to obtain the the impact of these 2 procedures aimed at enhancing the best response. smooth muscle relaxation process of the cavernous body on Evaluation of cavernous artery function was not signifipenile color Doppler sonography. Previously, we assessed the cantly improved by the addition of a second set of stimuli and modifications of color Doppler parameters induced by intra- new cases of arteriogenic impotence were not detected during corporeal injection of a vasoactive mixture with subsequent the last 2 phases of the test. Of our patients 4% had evidence genital and audiovisual sexual stimulation.16 In this study of decreased arterial inflow despite normal erections after the erectile response was upgraded after adjunctive genital injection 1 and genital and audiovisual sexual stimulation, and audiovisual sexual stimulation in 36% of the patients. which confirms our data and that of others,l6.z5 underlining Color Doppler sonography after the stimulation phase iden- the limitations of a simple injection test without concomitant tified 16% of the cases as arteriogenic despite normal erec- Doppler evaluation of the cavernous arteries as a diagnostic tions and 7% were falsely diagnosed as venogenic after the tool for cavernous artery function. Since the greatest increase injection phase. In our hands this preliminary association of of cavernous artery inflow occurs 1 to 3 minutes after the color Doppler sonography with the injection stimulation test intracorporeal injection,26 that is when intracorporeal resissignificantly improved the diagnostic potential of ultrasound, tance is minimal, significant changes in cavernous artery which had been previously used alone. However, we realized peak flow velocity were not noted after phase 1 or 3 of the that this experience did not totally eliminate the problem of test. However, peak systolic velocity values after genital and obtaining complete relaxation of the corporeal smooth muscle audiovisual sexual stimulation might increase in patients for reliable evaluation of the veno-occlusive mechanism. with a significant adrenergic discharge during the test,27 Thus, we decided to examine the impact of a second injection which can be counterbalanced by the relaxing effect of genital with subsequent genital and audiovisual sexual stimulation and audiovisual sexual stimulation. aimed a t enhancing corporeal smooth muscle relaxation in patients who had responded only partially to 1 injection with CONCLUSIONS genital and audiovisual sexual stimulation. Our study demonstrated that genital and audiovisual sexThe design of our study included administration of a second injection and subsequent genital and audiovisual sexual ual stimulation significantly enhances the erectile response stimulation in each patient except those who had achieved a after intracorporeal injection of vasoactive substances. To definite rigid erection after the first 2 phases of the test. study cavernous artery inflow and corporeal veno-occlusive According to our data it appeared that a second injection plus mechanism function, color Doppler sonography should be genital and audiovisual sexual stimulation decreased the performed aRer intracorporeal injection of vasoactive drugs number of patients with the diagnosis of venogenic impo- and subsequent genital and audiovisual sexual stimulation. tence established after phases 1 and 2 of the test (13versus When the maximal erection obtained at the end of the test is 17 patients), that is there were fewer false-positive results (4 lower than that obtained during sexual activity, the patient patients, 8%).This finding indicated further improvement in should undergo repeated intracorporeal injections of vasoacthe diagnostic potential of color Doppler sonography for eval- tive drugs followed by genital and audiovisual sexual stimuuating the cavernous veno-occlusive mechanism. Interest- lation until an erection considered optimal according to the ingly, patients who had a n improved erectile and Doppler usual standard is obtained. Although we recognize that pharresponse after the second set of stimuli were among those maco-cavernosometry, when performed during a phase of who reported a suboptimal erection after injection 1 and continuous linearity in the ratio between intracavernous genital and audiovisual sexual stimulation, that is less than pressure and maintenance flow, is the only procedure able to the maximal erection usually obtained during sexual activ- avoid false-positive diagnoses of corporeal veno-occlusive dysfunction, we believe that the association of multiple inity. Thus, we believe that, as previously reported by Goldstein,24 the occurrence during the test of an erection that jections and stimulations increases the diagnostic potential is not comparable to the erection naturally obtained by the of color Doppler sonography, which because of its low invasiveness might be considered the first line test to assess patient during sexual activity should be suspicious for incom- penile hemodynamics. plete activation of the corporeal veno-occlusive mechanism, Profs. Karine Winter Beatty and Barbra Berniz reviewed which is a potential source of false-positive diagnoses of venogenic impotence. In fact, after phase 4 of our study, 3 the language in the manuscript. patients still reported erectile responses less than the physiological erection. According to our study design these cases REFERENCES were diagnosed as venogenic but patients then underwent 1. Carrier, S.,Brock, G., Kour, N. W. and Lue, T. F.: Pathophysipolysomnographic recording of nocturnal erections for 3 ology of erectile dysfunction. Urology, 42: 468, 1993. nights a t our sleep laboratory, with measurements of axial 2. Krane, R. J., Goldstein, I. and Saenz de Tejada, I.: Impotence. and radial rigidity. One patient had a long episode of comNew Engl. J. Med., 321: 1648, 1989. plete penile rigidity demonstrating the integrity of vascular 3. Goldstein, I. and Krane, R. J.: Diagnosis and therapy of erectile dysfunction. In: Campbell's Urology, 6th ed. Edited by P. C. penile function (that is a false-positive diagnosis of venogenic Walsh, A. B. Retik, T. A. Stamey and E. D. Vaughan, Jr. impotence after our test), while in the other 2 only minimal Philadelphia: W. B. Saunders Co., VOI. 3, chapt. 84, pp. 3033erectile activity was noted despite a normal rapid eye move3072, 1992. ment sleep profile. 4. Broderick, G.A. and Arger, P.: Duplex Doppler ultrasonography: In clinical practice we believe that an intracorporeal injecnoninvasive assessment of penile anatomy and function. Sem. tion and subsequent genital and audiovisual sexual stimulaRoentgenol., 28.43, 1993. tion should be performed until a n erection comparable to the 5. Nisen, H.O., Saarinen, 0..Ruutu, M. L. and Edgren, J.: Duplex maximal physiological erection (that is the erection obtained Doppler scanning with prostaglandin E l in the diagnosis of at home during sexual activity) is reached. This clinical concavemovenous leakage. Acta Rad., 34:335,1993. 6. Kropman, R. F., Schipper, J., van Oostayen, J. A.. Lycklama a dition should correspond to the maximal corporeal smooth Nijeholt, A. A. B. and Meinhardt, W.: The value of increased muscle relaxation obtainable by the patient and, thus, it end diastolic velocity during duplex sonography in reshould allow for precise evaluation of the veno-occlusive _penile . - .

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lation to pathological venous leakage in erectile dysfunction. J. 17. Saenz de Tejada, I., Moroukian, P., Tessier, J., Kim. J. J., Goldstein, 1. and Frohrib, D.: The trabecular smooth muscle Urol., 148: 314, 1992. modulates the capacitor function of the penis. Studies on a 7. Hampson. S. J., Cowie, A. G., Richards, D. and Lees, W. R.: rabbit model. Amer. J. Physiol., 260: H1590, 1991. Independent evaluation of impotence by colour Doppler imag18. Virag, R.: Human penile erection: an extensive study of the ing and cavernosometry. Eur. Urol., 21: 27, 1992. effects of vasoactive compounds on the cavernous tissue and 8. Merckx, L. A,, De Bruyne, R. M. G., Goes, E., Derde, M. P. and the penile arteries. J. Urol., 1 3 3 191A. abstract 311, 1985. Keuppens, F.: The value of dynamic color duplex scanning in et Impuisthe diagnosis of venogenic impotence. J. Urol., 1 4 8 318, 1992. 19. Virag, R.: Drogues Vaso-actives-Papaverine sance-La Voie Pharmacologique. Paris: Editions du Ceri, 9. Kropman, R. F., van Oostayen, J. A., Zwinderman, K. H., 1987. Lycklama, G. A., Nijehold, A,, Schipper, J. and Meinhardt, W.: Relation of intracorporal pressure and end-diastolic velocity 20. Virag, R., Shoukry, K., Floresco, J., Nollet, F. and Greco, E.: Intracavernous self-injection of vasoactive drugs in the treatduring duplex Doppler sonography in the evaluation of venoment of impotence: 8-year experience with 615 cases. J. Urol., occlusive dysfunction. Int. J. Impotence Res., 6: 125, 1994. 145: 287, 1991. 10. Vickers, M. A., Benson, C. B. and Richie, J. P.: High resolution ultrasonography and pulsed wave Doppler for detection of 21. Hall, S., Honig, S. C., Payton, T. R., Krane. R. J. and Goldstein, I.: Use of atropine sulfate in pharmacological erections: initial corporovenous incompetence in erectile dysfunction. J. Urol., 143: 1125, 1990. experience with one-year followup in the United States. J. Urol., 147: 265A, abstract 206, 1992. 11. Montorsi F., Bergamaschi, F., Guazzoni, G., Ferini-Strambi, L., Barbieri, L. and Rigatti, P.: Morphodynamic assessment of 22. Montorsi, F., Guazzoni, G., Bergamaschi, F., Ferini-Strambi, L., Barbieri, L. and Rigatti, P.: Four-drug intracavernous therapy penile circulation in impotent patients: the role of duplex and for impotence due to corporeal veno-occlusive dysfunction. J. color Doppler sonography. Scand. J. Urol. Nephrol., 27: 399, 1993. Urol., 149: 1291, 1993. 12. Wespes, E. and Shulman, C.: Venous impotence: pathophysiol- 23. Montorsi, F., Guazzoni, G., Bergamaschi, F., Dodesini, A,, Rigatti, P., Pizzini, G. and Miani, A.: Effectiveness and safety ogy, diagnosis and treatment. J. Urol., 1 4 9 1238, 1993. of multidrug intracavernous therapy for vasculogenic impo13. Goldstein, I. and Nehra, A,: How I work up impotence and non-surgical management of impotence and priapism. J. Urol., tence. Urology, 42: 554, 1993. part 2, 151: 30A, 1994. 24. Goldstein, I., personal communication. 14. Katlowitz, N. M., Albano, G. J., Morales, P. and Golimbu, M.: 25. Pescatori, E. S., Hatzichristou, D. G., Namburi, S. and Goldstein, Potentiation of drug-induced erection with audiovisual sexual I.: A positive intracavernous injection implies normal venostimulation. Urology, 41: 431, 1993. occlusive but not necessarily normal arterial function: a hemo15. Donatucci, C. F. and Lue, T. F.: The combined intracavernous dynamic study. J. Urol., 151: 1209, 1994. injection and stimulation test: diagnostic accuracy. J. Urol., 26. Schwartz, A. N., Wang, K. Y., Mack, L. A., Lowe. M., Berger, 148: 61, 1992. R. E., Cyr, D. R. and Feldman, M.: Evaluation of normal erectile function with color flow Doppler sonography . AJR, 16. Montorsi, F., Guazzoni, G., Bocciardi, A., Barbieri, L, Rigatti, P., Pizzini, G. and Miani, A.: Improved minimally invasive assess1 5 3 1155, 1989. ment of penile hemodynamics: the combination of color 27. Iacono, F., Barra, S. and Lotti, T.: Evaluation of penile deep Doppler sonography and injection-stimulation test. Int. J. Imarteries in psychogenic impotence by means of duplex ultrapotence Res., 7: 33, 1995. sonography. J. Urol., 1 4 9 1262, 1993.