Value of 18F-FDG Accumulation in Mediastinal and Hilar Lymph Nodes on 18F-FDG PET/CT: Relation to Recurrence of Cardiac Sarcoidosis

Abstract

Purpose: 18F-fluorodeoxyglucose (18F-FDG) accumulation in the left ventricular (LV) wall detects active myocardial inflammatory lesions in cardiac sarcoidosis (CS), but the significance of 18F-FDG accumulation in mediastinal and hilar lymph nodes (LNs) remains unclear. We investigated the association between CS recurrence and 18F-FDG accumulation in the mediastinal and hilar LNs, using positron emission tomography/computed tomography (PET/CT). Materials and Methods: We retrospectively analyzed the records of 68 patients diagnosed with CS, who underwent 18F-FDG PET/CT before beginning treatment. The minimum follow-up period was 24 months. Patients were assigned to the recurrence (n=18) or no recurrence group (n=50) based on follow-up examinations. The 18FFDG PET/CT maximum standardized uptake value (SUVmax) was measured in the LV wall, right ventricular (RV) wall, and mediastinal and hilar LNs. The association of CS recurrence was analyzed using Cox proportional hazards models. Recurrence-free survival (RFS) curves were made using the Kaplan-Meier method. Results: In univariate analysis, sex, BNP, LVEF, and the SUVmax in the LV wall, RV wall, and mediastinal and hilar LNs were significant risk factors for CS recurrence. In multivariate analysis, only the SUVmax in the mediastinal and hilar LNs was a significant risk factor for CS recurrence. RFS rates were significantly higher in patients with an SUVmax<4.1 vs. ≥ 4.1 (log-rank value=36.0, p<0.01). Conclusion: The mediastinal and hilar LN SUVmax was an independent risk factor for CS recurrence after treatment. 18F-FDG accumulation in mediastinal and hilar LNs on 18F-FDG PET before treatment may be a useful biomarker to predict CS recurrence.