Can Quantitative 18F-FDG PET/CT and Serum Cytokine Analysis Differentiate ARVC from Cardiac Sarcoidosis?

Abstract Background Arrhythmogenic right ventricular cardiomyopathy (ARVC) and Cardiac Sarcoidosis (CS) may both cause malignant arrhythmia and sudden death, but differentiating the two can be difficult. Purpose To investigate the role of quantitative FDG PET/CT at distinguishing ARVC from CS, and explore whether addition of an inflammatory panel correlates with PET uptake, aiding diagnosis. Methods 10 patients with CS, 10 with ARVC were enrolled. Participants were prospectively studied with PET/CT. LV uptake was quantified using software and a 17-segment model, measuring maximum standardised uptake (SUVmax) and mean myocardial uptake, comparing these to a local normal reference range (21 volunteers) using a z-score. Blood levels of IL-1b, IL-6, IL-8, IL10, IL-12p40, MCP-1, TGFb, GRO, TNFa, IFNy, FGF2, PDGF were measured using ELISA, compared with 10 healthy controls. Results There were no significant differences in cytokine levels between CS and ARVC; most cytokine levels were higher in CS, except IL-6, IL-8 and MCP-1 in ARVC (Table 1). Increased PET uptake was noted in 1 segment of 1 ARVC patient, and in 1–2 segments of 5 CS patients (z-scores 2.25 SD; 2.15–2.38 SD). No pattern of uptake distinguished ARVC from CS, qualitatively assessing LV polar maps (Figure 1A, B). SUVmax and mean uptake were higher in CS vs. ARVC (p<0.05; p=0.13). No significant correlation between cytokine levels and PET uptake was detected (Figure 1C, D). Conclusion Quantitative PET/CT uptake and a blood inflammatory panel did not have utility in differentiating the two conditions in our population. There was generally more PET and serum inflammatory activity in CS. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): NHS Endowments