Spectral Doppler Sonography

Abstract

Sonography is a noninvasive, office-based diagnostic tool often used for evaluation of subfertile men. Previous studies have suggested that a resistive index (RI) greater than 0.6 is associated with impaired spermatogenesis. We sought to validate this threshold in a urologic patient population presenting for infertility evaluation. We retrospectively reviewed 99 consecutive patients seen for nonobstructive male infertility at our institution. Patient demographics, semen analysis parameters, hormone profiles, lipid profiles, and penile and scrotal sonographic measurements were recorded. The RI was calculated from measurements of the peak systolic velocity and end-diastolic velocity. Ninety-one patients fit the inclusion criteria and were subsequently divided into 2 groups based on RI: group 1 with RI values of 0.6 or less (n = 49) and group 2 with RI values greater than 0.6 (n = 42). Variables that were significantly different between the groups included age, total sperm count, percent motile sperm, total motile sperm, follicle-stimulating hormone, high-density lipoprotein, and testis volume. On the other hand, body mass index, forward progression, World Health Organization score, total testosterone, free testosterone, estradiol, total cholesterol, low-density lipoprotein, and triglycerides were not significantly different between the groups. A receiver operating characteristic curve revealed an area under the curve of 0.64 (confidence interval, 0.52-0.75; P = .025). At the threshold of greater than 0.6, the RI had specificity of 63.27% and a 1.56 likelihood ratio to predict total motile sperm less than 20 × 10(6) at spermatogenesis. An intratesticular RI greater than 0.6 is associated with impaired spermatogenesis. This finding supports the use of testicular spectral Doppler sonography as a noninvasive tool for evaluation of testicular function.