Cardiac MRI Strain for Prediction of PET-defined Myocardial Inflammation in Patients with Cardiac Sarcoidosis

Purpose To determine whether cardiac MRI strain parameters independently predict PET/CT-defined myocardial inflammation in patients with cardiac sarcoidosis (CS). Materials and Methods This retrospective study included patients with definite or probable CS who underwent cardiac MRI and fluorine 18 fluorodeoxyglucose (FDG) PET/CT between January 2010 and October 2022 within 90 days per the Japanese Circulation Society criteria. Strain parameters, including the peak circumferential strain (PCS), peak longitudinal strain (PLS), and diastolic strain rates, were calculated using feature tracking on cine steady-state free precession images. Inflammation was defined by focal FDG uptake using the 17-segment American Heart Association model. T2-weighted and late gadolinium enhancement (LGE) images were qualitatively assessed. Segment-level comparisons were performed between inflamed and noninflamed segments. Multivariable logistic regression clustered at the patient level was adjusted for LGE, T2 signal abnormality, age, sex, and left ventricular end-diastolic volume index. Receiver operating characteristic (ROC) curve analysis was used to evaluate the added value of strain metrics over the left ventricular ejection fraction (LVEF) for inflammation. Results Among 125 included patients (mean age, 59.5 years ± 12.7 [SD]), 60% (n = 75) had at least one segment with inflammation on FDG PET/CT images. Of these 75 patients, 61% (n = 46) were male. Segment-level analysis revealed inflammation in 18.1% (385 of 2125) of the segments. The PCS and PLS were lower in inflamed segments than in noninflamed segments (-14.1% vs -18.4% and -10.3% vs -13.0%, respectively; P < .001 for both) and independently predicted inflammation in multivariable analysis (odds ratio, 1.79 and 1.62, respectively; P < .01 for both). Adding PCS to LVEF improved inflammation detection (area under the ROC curve, 0.72 vs 0.63; P = .04). Conclusion Circumferential and longitudinal strain from cardiac MRI independently predicted PET-defined myocardial inflammation. Keywords: MRI, PET/CT, Heart, Cardiomyopathy, Cardiac Strain, Cardiac Sarcoidosis, Myocardial Inflammation © RSNA, 2026.