Testicular ultrasound score: A new proposal for a scoring system to predict testicular function

BACKGROUND: Testicular ultrasound (US) is routinely employed in the evaluation of reproductive and sexual function. However, its use for characteristics other than testicular volume is hampered by a lack of information on the prognostic value of its findings, which to date have only been incorporated in a score proposed by Lenz et al in 1993. OBJECTIVES: We sought to explore whether testicular US examination can predict the quality of spermatogenesis and provide information on testicular endocrine function. MATERIALS AND METHODS: We retrospectively reviewed 6210 testicular US examinations, finally selecting examinations from 2230 unique men. The following variables were considered: bitesticular volume and testicular asymmetry, parenchymal echotexture, echogenicity and presence of microlithiasis, solid lesions and varicocoele. Concurrent fasting hormonal data were available for 1160 men, while 979 had a semen sample available from the same day as the US examination. RESULTS: We derived a new US score, termed TU score, that can predict both impaired spermatogenesis (AUC 0.73, sensitivity 72%, specificity 61%, P < .001) and hypogonadism (AUC 0.71, sensitivity 71%, specificity 53%, P < .001) more accurately than the Lenz's score. In a multivariate analysis, a reduced sperm composite index (defined as total spermatozoa × total motility × normal forms) was independently predicted by bitesticular volume and by inhomogeneous echotexture, while hypogonadism was independently predicted also by reduced echogenicity and presence of microlithiasis. DISCUSSION AND CONCLUSIONS: We describe the testicular US characteristics that are independently associated with impaired spermatogenesis and hypogonadism and propose the TU score as a simple screening method for use in subjects referred for testicular US.