Assessment of myocardial fibrosis in ischemic and non-ischemic cardiomyopathies using cardiac magnetic resoance non-contrast T1ρ mapping

Aim To evaluate the performance of T1ρ mapping for myocardial fibrosis detection across distinct cardiomyopathy entities of ischemic and non-ischemic origin against native T1 mapping. Methods and results A total of 14 healthy controls and 39 patients [15 with ischemic cardiomyopathy [ICM], 12 with hypertrophic cardiomyopathy [HCM], and 12 with dilated cardiomyopathy [DCM]] underwent cardiac magnetic resonance (CMR), including T1ρ mapping, native T1 mapping, late gadolinium enhancement (LGE), and extracellular volume (ECV) mapping. Segments were visually classified as segments with or without LGE. T1ρ values were significantly higher in patients with ICM, HCM, and DCM than controls (all P < 0.05). T1ρ showed favorable diagnostic performance compared with native T1 in distinguishing ICM and HCM patients from controls [area under the curve (AUC): 0.959 vs. 0.739 for ICM; AUC: 0.878 vs. 0.763 for HCM], while both parameters exhibited comparable performance in DCM (AUC: 0.814 vs. 0.814). Notably, elevated T1ρ values were observed in segments with or without LGE. T1ρ mapping demonstrated good performance in distinguishing segments with LGE from those without LGE in ICM and HCM (AUC: 0.820 and 0.726) and exhibited a significant correlation with ECV across all disease types (ICM: r = 0.598; HCM: r = 0.577; DCM: r = 0.648; all P < 0.05). Conclusion This exploratory study demonstrates the potential of T1ρ mapping as a non-contrast CMR technique for detecting myocardial fibrosis in ischemic and non-ischemic cardiomyopathies. T1ρ showed favorable diagnostic performance compared with native T1 in ICM and HCM with comparable performance in DCM. These findings warrant validation in larger cohorts with diverse cardiac conditions to establish the clinical utility of T1ρ imaging.