18 F-FDG PET/CT use in functional assessment of the testes: a systematic review.

INTRODUCTION Our study analysed previous studies employing Positron Emission Tomography with co-registered Computer Tomography (PET/CT) in andrological patient evaluation and assessed the differences in 2-[18 F]F-fluoro-2'-deoxyglucose (FDG) uptake between 3 groups: healthy testes, benign and malignant testicular pathology. METHODS MEDLINE and EMBASE were systematically searched for studies involving FDG-PET/CT imaging of testes with results expressed as Mean Standardised Uptake Value (SUVmean ). A one-way ANOVA was used to compare SUVmean between 3 groups. All papers assessing andrological parameters were pooled to enable a comparison of fertility data. RESULTS Seventeen studies, including three relating to fertility diagnosis, with a total of 830 patients were included in the review. One-way ANOVA showed a statistical difference between mean values of tracer SUVmean in healthy and malignant testes (Dif. = -2.77, 95%CI = -4.32 to 1.21, p<0.01) as well as benign and malignant (Dif. = -2.95, 95%CI = -4.33 to -1.21, p<0.01) but no difference between healthy and benign (Dif. = 0.19, 95%CI = -0.96 to 1.33, p = 0.90). There is some evidence to suggest FDG uptake and testicular volume are positively correlated to total sperm count, sperm concentration and sperm motility and that germ cells are likely to account for the majority of testicular FDG accumulation. CONCLUSION Our findings indicate that malignant testicular lesions demonstrate a significantly higher FDG uptake than benign testicular lesions or healthy testes. Some evidence also suggests that FDG-PET could inform on metabolic activity and thus spermatogenesis, however more studies are needed to determine whether FDG-PET could also be used to determine differences between normal and oligospermic testes. Further studies should focus on correlating both sex hormone serum levels and semen analysis results with imaging data. This article is protected by copyright. All rights reserved.