Correlation of PET/CT with 18F-FDG and male fertility

Objectives Functional imaging of the testis could be a useful non-invasive tool in the andrological assessment of male hypofertility. Potential clinical applications may include post-chemotherapy azospermia and other causes of secretory azospermia. FDG uptake in testis is correlated with the presence of GLUT3 receptors in early spermatogenic cells. The aim of this original study was to determine a correlation between PET/CT using FDG and the sperm analysis.

Methods Retrospective study on young men before chemotherapy having accepted a cryopreservation and without known testicular pathology. The spermiological parameters were the total sperm count, the sperm count/ml, vitality and progressive motility after 1h (%). For most patients, a PET/CT (Discovery ST®) with FDG has been performed in the same week as the cryopreservation. As PET parameters the SUV max and mean as well as the functional testicular volume were studied.

Results Inclusion of 20 patients (average age: 22) of whom 19 had 2 spermograms. Semen parameters were within normal range for 65%, whereas 35% had oligospermia as a sign of hypofertility (<20 million spermatozoids/ml). The SUV max varied between 2 and 5.7. The analysis of Spearman showed a significant linear correlation between the SUV max and the averaged number of spermatozoids/ml (p < 0,05) as well as between the functional volume and the averaged number of spermatozoids/ml (p < 0,05). The Mann-Whitney test showed a significant difference of the SUV mean between the fertile and hypofertile men (p<0,05). In the hypofertile group we note a significant increase in the difference in uptake between both testis (p<0,05).

Conclusions This preliminary study shows a significant correlation between the testicular uptake of FDG and the main parameters of the spermogram. If these results are confirmed, PET/CT with FDG could have important clinical applications in diagnosis and prognosis of male hypofertility or sterility