A preliminary study on the effect of renal function on the metabolism of (18)F-FDG in the human cerebellum

BACKGROUND: The cerebellum is less affected by normal aging or neurodegenerative diseases, the aim of this paper is to investigate the effect of renal function status on uptake of 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) in human cerebellum based on independent creatinine (CRE) or blood urea nitrogen (BUN) levels. METHODS: A total of 253 patients who underwent (18)F-FDG PET/CT scans were included. The patients were divided into groups according to renal function status: 201 patients with normal renal function, 16 patients with increase CRE, 36 patients with decrease CRE, and 31 patients with abnormal BUN. The maximum standardized uptake values were obtained in regions of interest (ROIs) for multiple tissue types (right cerebellum, right lobe of liver, right lung, bone marrow and psoas muscle at the level of the fourth lumbar vertebra). Moreover, the selected normal CRE groups were pair-matched with CRE decrease group with respect to age, sex, body mass index and glucose, respectively. RESULTS: Among 253 patients who met the inclusion/exclusion criteria, the final analysis included 967 ROIs (244 cerebellum, 191 lungs, 230 muscles, 145 bone marrow, and 157 liver) from (18)F-FDG PET/CT scans. Among patients grouped by CRE or BUN levels, the uptake of (18)F-FDG by cerebellum was significantly decreased in patients with CRE decrease level (P=0.001). There were no statistically significant differences between the other groups. Matched-pair analysis indicated there were no significant changes in outcomes between the CRE decrease group and the age-, sex-, BMI-, and glucose-matched controls compared to pre-matching. CONCLUSIONS: In patients with normal renal function and reduced CRE concentration, decrease cerebellar glucose metabolism was observed; however, no abnormal uptake of (18)F-FDG was found in the cerebellum and other normal tissues of patients with impaired renal function. Consequently, in the study of cerebellar (18)F-FDG metabolism, it may be necessary to consider the influence of blood CRE level.