Clinical studies for venogenic impotence with color Doppler ultrasonography--evaluation of resistance index of the cavernous artery

Abstract

Pharmaco-dynamic infusion cavernosometry and cavernosography (pharmaco-DICC) is essential for diagnosis of venogenic impotence, however it is so invasive. On the other hand, color Doppler ultrasonography is non-invasive and has become one of the useful diagnostic methods for arteriogenic impotence. And there are some reports evaluating whether venogenic impotence can be diagnosed using color Doppler ultrasonography. In this study, we investigated whether the resistance index (RI) could be useful for screening for venogenic impotence. We performed color Doppler ultrasonography in 49 patients who had shown negative responses to an intracavernous injection of 20 mcg of prostaglandin E1 (PGE1). They previously underwent pharmaco-DICC and were diagnosed venogenic impotent when the maintenance flow rate was equal to or more than 20 ml/min. In 49 patients, 17 patients had DICC normality, while 32 patients had corporal leakages. After an intracavernous injection of 20 mcg of PGE1, we performed color Doppler ultrasonography, and measured peak systolic velocity (PSV) and end diastolic velocity (EDV) in the cavernous artery. RI was calculated as follows. RI = (PSV-EDV)/PSV We adopted the RI value near to 1 as the case's RI from two RI values of bilateral cavernous arteries, and compared RI values with the results of pharmaco-DICC. RI range in patients with normal DICC results was 0.895 +/- 0.092 (0.70-1.00), while RI range in patients with corporal leakages was 0.742 +/- 0.095 (0.55-0.97). RI values in patients with corporal leakages were significantly lower than those in patients with normal DICC results although there was some overlap in each group. From receiver-operating-characteristic curve (ROC curve) of the correlation between sensitivity and specificity at various RI values compared with DICC results, the RI cut off values were set up at 0.75 and 0.90, and classified the patients into 3 group according to their RI cut off values. In 10 patients with 0.9 < RI, 9 patients (90%) had DICC normality. In 17 patients with 0.75 < RI < or = 0.9, 7 patients had DICC normality while 10 patients had corporal leakages. In 22 patients with RI < or = 0.75, 21 patients (95.5%) had corporal leakages. We consider without carrying out pharmaco-DICC that patients with 0.9 < RI were not venogenic impotent, while patients with RI < or = 0.75 had corporal leakages. Pharmaco-DICC will remain essential only in patients with 0.75 < RI < or = 0.9.