128: Accuracy of a New Method for Semi-Quantitative Assessment of Right Ventricular Ejection Fraction by Cardiac MRI: Right Ventricle Fractional Diameter Change

Cardiovascular magnetic resonance (CMR) with endocardial delineation of the right ventricle is the gold standard to measure right ventricular ejection fraction (RVEF). Longitudinal shortening is historically known to be the predominant part of its global systolic function and less attention has been paid to the transversal contraction. The aim of this study was to evaluate RV transverse motion in a large cohort of patients referred for CMR and assess its relationship with RVEF. We retrospectively analyzed the CMR scans of 300 consecutive patients referred for CMR between January and December 2010. Reference RV ejection fraction was determined from short axis sequence after delineating endocardial contours. Transverse parameters called RV fractional diameter changes were calculated after measuring RV diastolic and systolic diameters at basal and medial level in short axis view (respectively FBDC and FMDC). We also measured the tricuspid annular plane systolic excursion (TAPSE) in the four chambers view as a longitudinal reference. Population was divided into 2 groups according the RVEF. 250 patients had a preserved RVEF (>40%) and 50 had a RV dysfunction (RVEF≤40%). Both transverse and longitudinal motions were significantly reduced in the group with RV dysfunction (p<.0001). After ROC analysis, areas under the curve for FBDC, FMDC and TAPSE, were respectively 0,79, 0,82 and 0,72 with the highest sensitivity and specificity of 68% and 88% for FMDC (threshold at 19.9%) to predict RVEF. Above all, FMDC had a 93% negative predictive value of altered RVEF. Right ventricular transversal systolic function markers, especially at the medial level, appear to be accurate for assessment of RV function by CMR. They are reliable to rule out an RV dysfunction in clinical practice.