RESUMEN
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.
RESUMEN
Objective:To investigate the clinical and cardiac magnetic resonance (CMR) characteristics of heart involvement in patients with Fabry disease (AFD).Methods:From January 2018 to March 2021, eight AFD patients [3 males and 5 females, mean age (50±11) years old, range 26-60 years old] confirmed by genetic testing or pathology in Fuwai Hospital were retrospectively included in this study. At the same time, sixteen patients with hypertrophic cardiomyopathy (HCM) [6 males and 10 females, mean age (46±15) years old] and 16 healthy individuals [6 males and 10 females, mean age (51±11) years old] were included as controls. The clinical baseline data and CMR data of the patients were collected and analyzed. The CMR data were analyzed using the software CVI42, with the corresponding parameters automatically generated. One-way ANOVA or Kruskal-Wallis test was used to compare the differences in the parameters among the three groups. Independent-samples t test, Fisher precise test or Mann-Whitney U test were used for the comparison between each two groups. Results:Statistically significant difference was found in renal insufficiency between the HCM group and the AFD group; No other significant difference was found in other clinical factors and ECG results (all P>0.05). CMR results showed that in the AFD group, there were 5 cases with symmetric or roughly symmetric hypertrophy, and 3 with asymmetric hypertrophy. The late gadolinium enhancement (LGE) showed myocardial enhancement in 5 patients, mainly presenting as multiple intermural enhancement, and partially as local subendocardial enhancement. In the HCM group, fourteen cases suffered mainly asymmetric ventricular septal thickening, with or without thickening of other parts of left ventricular wall; and 2 cases had thickening of middle and distal part of the left ventricle. The LGE showed myocardial enhancement in 14 patients, which manifested as focal or patchy enhancement in hypertrophic myocardium, including focal enhancement in the right ventricular insertion of ventricular septum (more common) and subendocardial enhancement in the middle and far segments of left ventricle. Statistically significant difference was found in the differences between the left atrial anterior posterior diameter, the maximum wall thickness of left ventricular, the left ventricular myocardial mass index (LVMI) and the native T 1 value among the three groups (all P<0.001). However, there was no statistically significant difference in the left atrial anterior posterior diameter and the maximum wall thickness of left ventricular between AFD group and HCM group ( P>0.05). The LVMI in AFD group was higher than that in healthy group and HCM group (all P<0.05). Significant difference was found in the native T 1 value among the three groups, with the native T 1 value of the AFD group [(1 177.4±46.0) ms] was significantly lower than that of the healthy group [(1 244.5±34.3) ms] and the HCM group [(1 278.8±41.6) ms], with ( F=13.10, P<0.001). Conclusions:The clinical characteristics of AFD and HCM are quite similar. When AFD is suspected, CMR imaging should be the first choice for imaging examination. Especially, T 1 mapping imaging can provide important information for the diagnosis of AFD.