Pericardial tissue characterization with quantitative methods in cardiac magnetic resonance in acute or recurrent pericarditis

Abstract Background Cardiac Magnetic Resonance(CMR) is gaining importance for diagnosis and prognosis stratification of pericarditis, and may help guide therapy especially in case of refractory symptoms. Data on quantitative evaluation of pericardial inflammation with CMR, including LGE and mapping techniques, are currently limited. Purpose to assess the utility of tissue characterization of pericardium with quantitative evaluation methods in outcome prediction of acute or recurrent pericarditis. Materials and Methods consecutive patients hospitalized or referred to our centre to perform CMR with a diagnosis of acute or recurrent pericarditis were enrolled. CMR performed within one month from diagnosis of acute/recurrent pericarditis and clinical follow up of at least 6 months were the inclusion criteria. In the postprocessing analysis of CMR images, quantitative evaluation of oedema and LGE amount on pericardium with different techniques i.e. 5 and 6 standard deviation (SD) and full width half maximum (FWHM) methods on inversion recovery (IR) and T2weighted (T2w) sequences and T1 and T2 maximum values measurement on inflamed pericardium with mapping were performed. Univariate/multivariate Cox regressions were performed to investigate the potential association between the different CMR quantitative parameters and the occurrence of recurrence; the propensity score based on clinical significant variables (age, gender, C-reactive protein values and therapy) was used as adjustment. Results sixty-one patients (mean age±SD: 48.43±18,2; male: 41%) who underwent CMR for acute or recurrent pericarditis were enrolled. Pericardial LGE and pericardial oedema detected on T2w were observed in 28(46%) and 31(50.8%) patients, respectively. Pericardial LGE median amount was 31.2(9.02;54.54)gr, 42.73(17.16;72.5)gr and 38.79(15.21;68.5)gr when measured with FWHM, 5SD and 6SD technique, respectively. Median pericardial T1 and T2 values were 1356(1305;1523)ms and 77(73;81)ms, respectively. During a median clinical follow up (FU) of 23(12;66) months, 17(28%) patients had a recurrence of pericarditis, 2(3%) developed constrictive pericarditis requiring pericardiectomy, 2(3%) were hospitalized for heart failure. Quantitative LGE, but neither T1 nor T2 mapping values nor T2w image, was associated to pericarditis recurrence and to composite outcome including constrictive evolution and heart failure hospitalization. The most accurate LGE method in prediction of clinical outcome was FWHM (HR 1.421; IC 1.124-1.795). Conclusion Quantitative LGE evaluation with different techniques, but not parametric mapping, showed an association with prediction of clinical recurrence of acute pericarditis, confirming LGE currently represents the most accurate imaging marker with prognostic value in this setting.CMR pericardial tissue characterization standardized HR pericarditis outcome