Suppression of myocardial 18F-FDG uptake with a preparatory "Atkins-style" low-carbohydrate diet

Abstract

Objectives: Physiological myocardial uptake of 18F-FDG during positron emission tomography can mask adjacent abnormal uptake in mediastinal malignancy and inflammatory cardiac diseases. Myocardial uptake is unpredictable and variable. This study evaluates the impact of a low-carbohydrate diet in reducing myocardial FDG uptake.

Method: Patients attending for clinically indicated oncological FDG PET were asked to have an "Atkins-style" low-carbohydrate diet (less than 3 g) the day before examination and an overnight fast. A total of 120 patients following low-carbohydrate diet plus overnight fast were compared with 120 patients prepared by overnight fast alone. Patients having an Atkins-style diet also completed a diet compliance questionnaire. SUV(max) and SUV(mean) for myocardium, blood pool and liver were measured in both groups.

Results: Myocardial SUV(max) fell from 3.53 ± 2.91 in controls to 1.77 ± 0.91 in the diet-compliant group. 98 % of diet-compliant patients had a myocardial SUV(max) less than 3.6 compared with 67 % of controls. Liver and blood pool SUV(max) rose from 2.68 ± 0.49 and 1.82 ± 0.30 in the control group to 3.14 ± 0.57 and 2.06 ± 0.30.

Conclusion: An Atkins-style diet the day before PET, together with an overnight fast, effectively suppresses myocardial FDG uptake.

Key points: • Low-carbohydrate diet (LCD) the day before PET suppresses myocardial FDG uptake. • LCD before PET increases liver and blood pool SUV ( max ) and SUV ( mean ). • Suppression of myocardial uptake may improve PET imaging of thoracic disease. • Suppression of myocardial uptake may help imaging cardiac inflammatory disease with PET.