From the Guidelines
Patients should consume a high-fat/low-carbohydrate meal before a PET scan to suppress physiologic myocardial FDG uptake, as recommended by the expert panel in the JACC: Cardiovascular Imaging journal 1. The goal of this dietary preparation is to create optimal conditions for the PET scan by reducing the uptake of the radiotracer in normal tissues and increasing its uptake in targeted tissues.
- A high-fat/low-carbohydrate meal can help suppress myocardial glucose uptake, leading to better image quality and more accurate diagnostic information.
- Fasting overnight or for at least 4 hours after a high-fat/low-carbohydrate meal can also help reduce background noise in the scan images.
- The expert panel recommends that patients log their exact dietary preparation to ensure compliance and comparison with follow-up imaging 1. Some key points to consider when preparing for a PET scan include:
- Consuming a high-fat/low-carbohydrate meal, such as dinner, the night before the scan, and then fasting overnight 1.
- If the scan is scheduled in the late morning or early afternoon, a high-fat/low-carbohydrate breakfast can be consumed, followed by at least 4 hours of fasting 1.
- For patients who are vegan or vegetarian, a single fast for more than 18 hours before the study is suggested if they cannot consume a high-fat diet 1.
From the Research
Use of Fat and Meat in Positron Emission Tomography (PET) Scan
- Fat and meat are used in the preparation for a Positron Emission Tomography (PET) scan to reduce the uptake of 18F-FDG by the myocardium, brown adipose tissue, and skeletal muscle 2, 3, 4.
- A low-carbohydrate, high-fat diet before PET/CT scanning can reduce the degree of 18F-FDG uptake by the myocardium, brown adipose tissue, and skeletal muscle, resulting in more accurate diagnostic interpretation 5, 2.
- The use of a high-fat, low-carbohydrate, and protein-permitted diet for 24 hours or more before the scan can suppress physiological myocardial uptake of FDG, helping to identify active cardiac sarcoidosis 3, 4.
- A prolonged 72-hour high-fat, high-protein, and very-low-carbohydrate diet preparation can successfully suppress physiological myocardial FDG uptake, permitting a more sensitive and accurate method of diagnosing active cardiac sarcoidosis using FDG PET/CT 4.
- The diet preparation methods can decrease uptake of 18F-FDG by myocardium, brown adipose tissue, and skeletal muscle, improving the diagnostic accuracy of 18F-FDG PET/CT scans 2.