Characterization of cardiac sarcoidosis in Iranian patients using cardiac magnetic resonance and positron emission tomography imaging techniques.

Background: Cardiac involvement in sarcoidosis is associated with high mortality but is often underrecognized due to diagnostic challenges. Advanced imaging modalities like Cardiac Magnetic Resonance (CMR) and Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) are highly sensitive for detecting myocardial inflammation and scarring, aiding in the diagnosis and management of cardiac sarcoidosis. The objective of this study was to characterize the imaging features of cardiac sarcoidosis in Iranian patients using these advanced cardiac imaging modalities.

Materials and methods: This multicenter prospective study included 42 Iranian patients with biopsy-proven extracardiac sarcoidosis who met the Japanese Circulation Society criteria for cardiac involvement. All patients underwent CMR to evaluate myocardial function, edema, scarring, and strain. 28 patients also underwent FDG-PET/CT to assess active myocardial inflammation.

Results: In our study of 42 cardiac sarcoidosis patients (50% male, mean age 47.14±14.33 years), CMR revealed reduced left ventricular ejection fraction (34.2±13.7%) in 83.3% of patients, with late gadolinium enhancement (LGE) present in 88.1%. LGE was most frequent in the basal anteroseptal and mid inferoseptal/anteroseptal segments, with midwall (35.5%) and subepicardial (23.7%) patterns predominating. Global strain analysis showed impaired values: longitudinal -10.08±4.14%, radial 15.38±8.55%, and circumferential -10.79±4.63%. Mean T1 and T2 values were 1054.60±50.98 ms and 52.59±4.53 ms, respectively. FDG-PET demonstrated active disease in 67.9% of cases, predominantly involving the apical septum, basal inferolateral, and mid inferolateral segments. The left anterior descending artery territory showed the highest involvement in both active inflammation (44.3% of affected segments) and scarring (39.2% of affected segments).

Conclusion: CMR and FDG-PET provided comprehensive assessment of cardiac involvement in this Iranian cardiac sarcoidosis cohort, with predominant basal and lateral wall involvement. Regional differences highlight the importance of population-specific studies.