To explore the effect of dietary intake before fasting on the physiological distribution of ¹⁸F-FDG PET/CT, and to improve the ¹⁸F-FDG PET/CT image quality.

From August 2019 to May 2020, questionnaire of dietary intake before fasting of 118 patients (73 males, 45 females; age (58.4±13.4) years) who performed PET/CT imaging in Zhongshan Hospital, Fudan University were retrospectively analyzed. The total dietary energy intake, the nutrient intake and energy supply ratio of the three energy source nutrients, the type of raw materials and the texture of diet were included. The SUV_max and SUV_mean of the liver, mediastinal blood pool and hip muscles were measured. Single-factor and multi-factors linear regression analyses were used to analyze data.

The fasting blood glucose of 118 subjects was (5.36±1.01) mmol/L. The texture of diet before fasting were general diet, semiliquid diet and liquid diet, which were 42 (35.59%), 72 (61.02%) and 4 (3.39%) subjects, respectively. The energy supply ratios of carbohydrate, protein and fat were (55.46±18.27)%, (16.70±7.38)% and (27.72±14.53)%, respectively. The results of multi-factors regression analysis indicted that protein energy ratio was an independent factor influencing SUV_max (β=0.005, P=0.031) and SUV_mean (β=0.003, P=0.042) of the hip muscles, and the texture of diet was an independent factor influencing SUV_max (β=0.126, P=0.030) and SUV_mean (β=0.197, P=0.002) of mediastinal blood pool.

The dietary intake before fasting has significant effect on the imaging quality of ¹⁸F-FDG. The protein energy ratio is an independent factor influencing SUV_max and SUV_mean of the hip muscles. The texture of diet is an independent factor influencing SUV_max and SUV_mean of mediastinal blood pool.

Fasting; Diet; Positron-emission tomography; Tomography, X-ray computed; Fluorodeoxyglucose F18