T 1 rho mapping for assessment of myocardial fibrosis in hypertrophic cardiomyopathy / 中华放射学杂志

ABSTRACT

Objective:To investigate the value of T 1ρ mapping in the assessment of myocardial fibrosis in patients with hypertrophic cardiomyopathy (HCM). Methods:Forty HCM patients and 16 healthy volunteers who underwent CMR examination between December 2021 and May 2022 were prospectively enrolled. T 1ρ mapping, pre-and post-contrast T 1 mapping, and gadolinium contrast-enhanced delayed enhancement (LGE) imaging were performed in HCM patients, while T 1ρ mapping and T 1 mapping were performed in volunteers. HCM patients were further divided into LGE-positive (LGE+) and LGE-negative (LGE-) groups based on the presence or absence of LGE. The T 1ρ and pre-contrast T 1 values of the left ventricular myocardium of HCM patients and volunteers were measured, and the extracellular volume fraction (ECV) of the left ventricular myocardium of HCM patients was measured using pre-and post-contrast T 1 mapping. One-way ANOVA was used to compare the T 1ρ and pre-contrast T 1 values among the LGE+, LGE-, and volunteer groups, and pairwise comparisons were further corrected using the Bonferroni method. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic performance of pre-contrast T 1 and T 1ρ values in distinguishing LGE+ and LGE- patients from volunteers. The chi-square test or Fisher′s exact probability test was used for categorical variable comparisons. Pearson correlation coefficient was used to evaluate the correlation between T 1ρ and pre-contrast T 1, and ECV. Results:There were no significant differences in age, gender, and body surface area among the LGE+, LGE-, and healthy control groups ( P>0.05). Compared to the HC group, both the T 1ρ value ( t=5.74, P<0.001) and the pre-contrast T 1 value ( t=3.99, P<0.001) increased in LGE positive group, as well as in the LGE negative group (T 1ρ: t=4.19, P<0.001; T 1: t=2.06, P<0.044). ROC analysis showed that the area under the curve (AUC) of T 1ρ and pre-contrast T 1 in distinguishing LGE+patients from healthy controls were 0.93 (sensitivity 84.0%, specificity 93.8%) and 0.87 (sensitivity 84.0%, specificity 87.5%), respectively. The AUC of T 1ρ and pre-contrast T 1 in distinguishing LGE-patients from healthy controls were 0.84 (sensitivity 86.7%, specificity 68.8%) and 0.68 (sensitivity 60%, specificity 68.8%), respectively. The correlation analysis showed that the T 1ρ value of the left ventricular myocardium was positively correlated with the pre-contrast T 1 value ( r=0.31, P=0.02) and ECV value ( r=0.38, P=0.02). Conclusion:Without the use of contrast agents, T 1ρ mapping shows good performance for myocardial replacement fibrosis and diffuse fibrosis in HCM patients.