Keto diet may improve cardiac sarcoidosis diagnosis via PET/CT: Study
USA: Following a 72-h daytime ketogenic diet with 3-day overnight fasting can help to achieve superior myocardial suppression for diagnosis of cardiac sarcoidosis (CS) with 18F-FDG PET/CT, finds a recent study. Accoridng to the study, published in the Journal of Nuclear Medicine, this results in significantly fewer potentially "false positive" and "indeterminant" CS results.
Cardiac sarcoidosis is a rare disease characterized by granulomas formation in the heart tissue. It can cause heart failure and arrhythmias. For its diagnosis, FDG-PET/CT is emerging to be a promising alternative to invasive biopsies. Physicians need to differentiate between normal physiologic myocardial activity and abnormal myocardial inflammation for which the patient's consumption of glucose needs to be suppressed.
Can Ozutemiz, University of Minnesota, United States, and colleagues aimed to compare three different dietary preparations in achievement of the best myocardial suppression and CS diagnosis.
For the purpose, the researchers retrospectively reviewed and compared three dietary preparations used at their institution. Three different diets are applied from 03/2014 to 12/2019 -- 24-h ketogenic diet with overnight fasting (n = 94); 18h-fasting (n = 44); 72-h daytime ketogenic diet with 3-day overnight fasting (n = 98).
The interpretation of initial reports was recorded, and an independent radiologist (observer) retrospectively re-evaluated each case regarding CS diagnosis (Negative, Positive, Indeterminant) and myocardial suppression (Complete, Failed, Partial). Interobserver agreement was analyzed. MaxSUV was measured from bloodpool, liver, and the most suppressed normal myocardium.
Key findings of the study include:
- Superior myocardial suppression was identified with the 72-h preparation indicated by a higher bloodpool/myocardium and liver/myocardium ratios.
- Myocardial suppression rates for 72-h ketogenic diet, 24-h ketogenic diet and 18-h fasting preparations are as follows; Complete myocardial suppression: 96.9%/68.1%/52.3%, Failed myocardial suppression: 0%/23.4%/25%, Partial myocardial suppression: 3.1%/8.5%/22.7%).
- The 72-hour preparation had significantly fewer "indeterminant" and "positive" exams.
- CS diagnosis rates for 72-h ketogenic diet, 24-h ketogenic diet and 18-h fasting preparations are as follows; Negative: 82.7%/52.1%/27.3%, Indeterminant: 2.0%/24.5%/40.9%, Positive: 15.3%/23.4%/31.8%.
- High agreement was present with the observer and the report (κ=0.88).
"A 72-h daytime ketogenic diet with 3-day overnight fasting, achieved substantially superior myocardial suppression versus 24-h ketogenic diet with overnight fasting and 18h-fasting using 18F-FDG PET/CT," wrote the authors. "This 72-h preparation results in significantly fewer "indeterminant" and potentially "false positive" CS results."
The study titled, "Comparison of the effect of three different dietary modifications on myocardial suppression in 18F-FDG PET/CT evaluation of patients for suspected cardiac sarcoidosis," is published in the Journal of Nuclear Medicine.