Age- and gender-related normal references of right ventricular strain values by tissue tracking cardiac magnetic resonance: results from a Chinese population

BACKGROUND: Myocardial deformation is a sensitive marker for sub-clinical myocardial dysfunction and carries independent prognostic significance across a broad range of cardiovascular diseases. Reproducible and repeatable assessment of right ventricular (RV) function is vital for monitoring congenital and acquired heart diseases. The purpose of this study was to determine the normal references of RV strain and strain rate values using tissue tracking cardiac magnetic resonance imaging (MRI). METHODS: A cohort of 120 normal human subjects from each decade of life between 20 and 70 without cardiac diseases were enrolled in this study. Retrospectively, electrocardiogram (ECG) gating cardiac MRI imaging was performed at 3.0T with balanced steady-state free precession (bSSFP) imaging. RV global and segmental myocardial strains were analyzed by tissue tracking by two experienced observers. RESULTS: The global peak longitudinal strain (GLS) and global peak radial strain (GRS) was -24.3±4.7 and 23.0±8.5 respectively. For the peak circumferential strains (GCS), the values for global, basal, mid-cavity, and apical segments were -13.3±4.1, -13.1±4.0, -12.5±4.7, and -15.9±5.8, respectively. There were significant gender differences in peak GRS (P=0.009) and at the base (P=0.017) and the mid-cavity (P=0.011) with greater deformation in females than in males. There were also significant age differences in GRS (P<0.001), GCS for basal (P<0.001), and mid-cavity segments (P=0.037). On Bland-Altman analysis, peak GLS and GRS had the best intra-observer agreement (mean bias, -0.13±0.51; 95% CI, -1.13-0.87) and inter-observer (mean bias, 0.054±0.31; 95% CI, -0.55-0.66) agreement, respectively. CONCLUSIONS: Normal values of RV deformation for healthy individuals using tissue tracking cardiac magnetic resonance (CMR-TT) provided good RV peak strain reproducibility. There was a significant correlation between RV strain or strain rate parameters with either age or sex.