Left Ventricular Myocardial T1 Values and Extracellular Volume Fraction in Asymptomatic Subjects: Variations According to Left Ventricular Segments and Correlation with Cardiovascular Risk Factors

Abstract

Purpose: To evaluate the normal range and variation in pre-contrast (preT1) and post-contrast (postT1) myocardial T1 values and extracellular volume fraction (ECV) according to left ventricular (LV) segments and to check for correlations between them and known cardiovascular risk factors.Methods: This study included 233 asymptomatic subjects (210 men and 23 women; aged 54.1±6.0 years) who underwent cardiac magnetic resonance imaging with preT1 and postT1 mapping on a 1.5-T scanner. T1 values and ECVs were compared among LV segments, age groups, and sex, and correlated with renal function. Based on the presence of hypertension (HTN) and diabetes mellitus (DM), the subjects were subdivided into the control (n=121), HTN (n=58), DM (n=25), and HTN and DM (HTN-DM) groups (n=29).Results: T1 values and ECV showed significant differences between the basal septal and lateral segments (p≤0.001) and between the mid-septal and mid-lateral segments (PreT1 p≤0.003, postT1 and ECV p<0.001). Among subgroups according to the HTN and DM status, the HTN-DM group showed a significantly higher ECV (0.260±0.023) than the control (0.240±0.021, p=0.011) and HTN (0.241±0.024, p=0.041) groups. Overall postT1 and ECV of the LV had significant correlation with the estimated glomerular filtration rate (r = 0.19, p=0.038 for postT1; r = -0.23, p=0.011 for ECV).Conclusion: Septal segments show higher preT1 and ECV but lower postT1 than lateral segments at the mid-ventricular and basal levels. ECV is significantly affected by cardiovascular risk factors such as HTN, DM, and decreased renal function, even in asymptomatic subjects.