Clinical value of a high-fat and low-carbohydrate diet before FDG-PET/CT for evaluation of patients with suspected cardiac sarcoidosis.

BACKGROUND: We hypothesized that a high-fat and low-carbohydrate (HFLC) diet before FDG-PET/CT could identify patients with active cardiac sarcoidosis (CS). METHODS: Fifty-eight sarcoidosis patients with a suspicion of CS consumed a HFLC diet before FDG-PET/CT. Clinical, electrical, and other imaging investigations were compared to PET results. RESULTS: Using Japanese Ministry of Health and Welfare (JMHW) criteria as a gold standard, 21% (12/58) of patients had a CS. Sensitivity and specificity of PET (visual analysis) were 83% (10/12) and 78% (36/46), respectively, with a very good interobserver agreement (k = 0.86). 70% (7/10) of the patients with a positive PET and negative JMHW criteria exhibited abnormalities suggestive of CS either on MR (n = 3) or SPECT (n = 4). Comparison with the presence of delayed enhancement on magnetic resonance imaging helped to classify patients with active (PET positive) or non-active CS (PET negative). In addition, when MR and PET were both negative, none of the patients met the JMHW criteria. PET response under treatment was concordant with clinical evolution in 11/13 patients. CONCLUSIONS: FDG-PET/CT after HFLC diet is a sensitive tool for the diagnosis of active CS. Combined use of PET and MR is promising for the detection and characterization of CS lesions.