Background18F-FDG-PET/MR can identify inflammation and fibrosis, high-risk features in cardiac sarcoidosis. ObjectiveTo evaluate whether the involvement of certain myocardial segments is associated with higher risk compared to others. Methods124 patients with suspected clinical sarcoidosis underwent 18F-FDG-PET/MR. Late gadolinium enhancement (LGE) and focal 18F-FDG uptake were evaluated globally and in the 16 myocardial segments. Presence of LGE was defined when the percentage of LGE exceeded 5.7% globally (relative to myocardial volume) and in each myocardial segment. Patients were followed up for 5.5 years. Events were defined as ventricular arrhythmia (VA, including sustained ventricular tachycardia, ventricular fibrillation, and appropriate ICD discharge), heart failure hospitalization, or all-cause death. ResultsMean age was 57.1±8.9 years, and 39.5% were female; 22 patients (17.6%) had an event at follow-up, and 9 (7.2%) presented VA. LGE and 18F-FDG uptake were more frequent in patients with than without events (36.4% vs 7.8%, p=0.001). Presence of LGE or 18F-FDG in the basal anterior segment were independent predictors for events after adjustment by left ventricular ejection fraction and relative enhanced volume (LGE: OR 10.5[1.2-92.4]; p=0.034;18F-FDG: OR 5.5[1.1-27.5], p=0.038). LGE presence in basal to mid anterior, mid anteroseptal, and basal to mid inferoseptal segments was an independent predictor for VA. Presence of 18F-FDG in basal to mid anterior, mid inferoseptal and mid inferior segments was an independent predictor for VA. ConclusionInvolvement of specific myocardial segments, particularly basal to mid anterior and mid septal segments, is associated with higher rates of events in patients with suspected cardiac sarcoidosis.