We aim to investigate the correlations between hemodynamic parameters, penile rigidity grading, and the therapeutic effects of phosphodiesterase type 5 inhibitors using color Doppler flow imaging after intracavernosal injection in patients with erectile dysfunction. This study involved 164 patients. After intracavernosal injection with a mixture of papaverine （60 mg）, prostaglandin E1 （10 μg）, and lidocaine （2%, 0.5-1 ml）, the penile vessels were assessed using color Doppler flow imaging. Penile rigidity was classified based on the Erection Hardness Score system as Grades 4, 3, 2 or 1 （corresponding to Schramek Grades Ⅴ to Ⅱ）. Then, the patients were given oral sildenafil （50-100 mg） and scored according to the International Index of Erectile Function （IIEF-5） questionnaire. The number of patients with penile rigidities of Schramek Grades Ⅱ to Ⅴ was 14, 18, 21, and 111, respectively. The IIEF-5 score was positively correlated with the refilling index of the penile cavernosal artery （r = 0.79, P 〈 0.05）, the peak systolic velocity （r= 0.45, P〈 0.05）, and penile rigidity （r= 0.75, P〈 0.05）, and was negatively correlated with the end diastolic velocity （r = -0.74, P 〈 0.05）. For patients with erectile dysfunction, both the IIEF-5 score after sildenafil administration, which is correlated with penile rigidity, and the hemodynamic parameters detected using color Doppler flow imaging may predict the effects of phosphodiesterase type 5 inhibitor treatment and could provide a reasonable model for the targeted-treatment of erectile dysfunction.
