Right ventricular (RV) dysfunction is known to be highly correlated with mortality and morbidity; nevertheless, imaging-based assessment of RV anatomy and physiology lags far behind that of the left ventricle. In this study, we advance RV imaging using cardiac magnetic resonance (CMR) to accomplish the following aims: (i) track the motion of six tricuspid annular (TA) sites using a semi-automatic tracking system; (ii) extract clinically important TA measurements-systolic velocity (Sm), early diastolic velocity (Em), late diastolic velocity (Am), and TA plane systolic excursion (TAPSE)-for each TA site and compare these CMR-derived measurements in healthy subjects vs. patients with heart failure, repaired tetralogy of Fallot, pulmonary hypertension, and hypertrophic cardiomyopathy; (iii) investigate how the TA motion related measurements compare with information provided by invasive right heart catheterization (RHC); (iv) evaluate the rate of change in surface area swept out by the reconstructed tricuspid annulus over time and (v) assess the reproducibility of this CMR-based technique. Results indicate that TA motion parameter data obtained in three dimensions using the proposed CMR-based systematic methodology achieve superior diagnostic performance (Sm: AUC = 0.957; TAPSE: AUC = 0.981) compared to two-dimensional CMR imaging. Both Sm and TAPSE from CMR correlated positively with dP/dt max/IP from RHC (Sm: r = 0.621, p < 0.01; TAPSE: r = 0.648, p < 0.01). Our highly reproducible and robust methodology holds potential for extending CMR imaging to characterization of TA morphology and dynamic behaviour, eventually leading to deeper understanding of RV function and improved diagnostic capability.
Keywords: Cardiac magnetic resonance; Right ventricular function; Tricuspid annulus.