Functional testicular evaluation using PET/CT with 18F-fluorodeoxyglucose.

PURPOSE: PET/CT using (18)F-FDG is a well-established diagnostic examination in oncology, cardiology and neurology. The clinical significance of nontumoral testicular uptake of FDG is unknown. Functional testicular imaging may have important clinical applications in the diagnosis and prognosis of male infertility. The aim of this study was to determine the andrological value of a FDG PET/CT in analysing testicular function, by correlating the PET/CT data with the sperm parameters.
METHODS: Retrospective analysis of FDG PET/CT in 20 consecutive cancer patients without testicular pathology in whom two semen samples had been obtained for analysis before any chemotherapy. FDG PET/CT parameters were the mean standardized uptake value (SUVmean), used for measuring the intensity of uptake, and the functional testicular volume (FV). For statistical analysis, a Spearman's rank correlation test and a Mann-Whitney test were used.
RESULTS: Of 20 patients (mean age 22 years), 18 had provided two sperm samples for cryopreservation. Sperm concentration was above 20 × 10(6)/ml in 55% of the patients. The intensity of uptake and the FV were correlated with the total sperm count, the sperm concentration and motility (p < 0.05). The difference in SUVmean between the two testes showed an inverse correlation with sperm concentration (p = 0.036). Normospermic and oligospermic men had significant differences in: (1) mean SUVmean, (2) mean FV, and (3) the difference in intensity of uptake between the testes (p < 0.05).
CONCLUSION: This is the first report on the andrological value of FDG PET/CT in analysing nontumoral testicular function. This pilot study showed a significant correlation between intensity of uptake of FDG and testicular FV with the main sperm parameters. PET/CT with FDG could become a useful new tool in assisted reproductive technologies and other andrological or urological applications.