Routine breath-hold gradient echo MRI-derived right ventricular mass, volumes and function: accuracy, reproducibility and coherence study

Abstract

Right ventricular (RV) dysfunction is a predictor of poor outcome in patients with heart disease. Conventional imaging modalities fail to assess RV volumes accurately. We sought to assess the accuracy and reproducibility of routine breath-hold gradient echo magnetic resonance imaging (MRI)-derived RV mass, volumes and function. We assessed: (1) The accuracy of in vivo MRI-derived RV mass in comparison to the RV weight in 9 minipigs. (2) Intra- and inter-observer reproducibility of RV mass, end-diastolic (EDV) and end-systolic (ESV) volumes and ejection fraction (EF) in 15 normal volunteers and 10 patients with heart disease. (3) Inter-study reproducibility of the former parameters in 25 coronary artery disease patients. (4) The correlation between right and left ventricular stroke volumes in the total population. Strong statistically significant correlations were found between: (1) MRI-derived RV mass and RV weight (r = 0.98, bias = 2.5 g), (2) Intra-observer measurements of RV mass (r = 0.96, bias = 0.5 g), EDV (r = 0.99, bias = -1.5 ml), ESV (r = 0.98, bias = 0.1 ml) and EF (r = 0.92, bias = -1.4%), (3) Inter-observer measurements of RV mass (r = 0.95, bias = 1.1 g), EDV (r = 0.98, bias = -1.1 ml), ESV (r = 0.98, bias = 1.2 ml) and EF (r = 0.87, bias = -1.9%), (4) Inter-study measurements of RV mass (r = 0.91, bias = -0.1 g), EDV (r = 0.96, bias = 3.8 ml), ESV (r = 0.98, bias = 0.3 ml) and EF (r = 0.90, bias = 0.9%), (5) MRI-derived right and left ventricular stroke volumes (r = 0.87). The assessment of the RV mass, volumes and function by routine breath-hold gradient echo MRI is accurate and highly reproducible. The correlation between left and RV MRI-derived stroke volumes indicates excellent coherence of simultaneous bi-ventricular volume measurements.