Clinical significance of incidental pericardial late gadolinium enhancement on cardiac magnetic resonance

BACKGROUND: Pericardial late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) is typically interpreted as a marker of active pericardial inflammation. However, it may also be detected incidentally during CMR performed for unrelated indications, and its clinical significance remains unclear. Whether incidental pericardial LGE reflects persistent subclinical inflammation associated with adverse long-term outcomes is unknown. METHODS: We conducted a retrospective single-center study including consecutive patients undergoing clinically indicated CMR. Patients with incidentally detected pericardial LGE were identified and compared with a control population without LGE. Clinical characteristics, CMR findings, and long-term outcomes were collected. The primary endpoint was the development of constrictive pericarditis (CP) during follow-up. RESULTS: Among 590 patients, incidental pericardial LGE was identified in 31 (5.3%), while 559 patients had no LGE. During a median follow-up of 72 months, CP occurred in 2 patients (6.5%) with LGE and in none of the patients without LGE (p = 0.003). Patients with LGE more frequently had a history of pericarditis and showed higher prevalence of pericardial effusion and increased pericardial thickness on CMR. CONCLUSIONS: Incidental pericardial LGE on CMR was associated with a history of prior pericardial and myocardial inflammation, and CP occurred only among patients with LGE during follow-up. However, these findings should be interpreted cautiously, as LGE may represent a surrogate marker of an underlying inflammatory pericardial substrate rather than an independent prognostic marker. Larger prospective studies are needed to determine whether incidental pericardial LGE provides prognostic information beyond clinical history.