Diagnostic Value ofDouble Injection ofVasoactive Drug in Penile Doppler Ultrasonographyl

Purpose : To evaluate the usefulness of double injection of a vasoactive drug in penile Doppler ultrasonography for the diagnosis ofvasculogenic impotence. Materials and Methods: Eighty-four consecutive cases(bilateral sides) of 42 patients with suspected vasculogenic impotence were included in our study. We used computed sonography(Acuson, USA), with a 7 MHz linear array transducer. After the first intracavernosal injection of the vasoactive drug( lOμg of prostagladin E 1), peak systolic velocity(PSV) and end diastolic velocity(EDV) were measured three times. According to mean PSV and EDV, the patients were classified into four groups: arteriogenic impotence(AI; N = 29), venogenic impotence(VI; N = 28), AI associated with VI(N= 14), and normal(N= 13). After the second injection, PSV and EDV were remeasured , using the same method. Mean velocities of the first injection were compared with those of the second, and the paired t-test was used to analyze the results. The extent to which patients were reclassified after the second injection was noted. Results : In all four groups, PSV measured after the second injection was significantly different from PSV after the first(P=O.OOOl , 0.0001 , 0.0010, 0.0072) ; except in the normal group, EDV measured after the second injection was not different from EDV afterthe first (P = 0.9815, 0.0654, 0.0950, 0.0057). After the second injection, the numbers of patients reclassified into other groups were as follows : AL 11(38%); VI, 6(21 %); AI associated with VI, 11(79%); normal, 1 (8%). Conclusion : Double injection of a vasoactive drug affected PSV, and therefore, appears to be a useful adjunctive procedure for the evaluation of patients in whom classification based on the results ofthe first injection is difficult.