MRI Assessment of the Effect of Preload on Ventricular Volumes and Function in Healthy Adult Volunteers

One of the many uses of cardiac magnetic resonance (CMR) is the assessment of right ventricular (RV) volumes. There are a number of congenital heart defects and acquired conditions in which management decisions are fundamentally based on ventricular volumes. The "gold standard" for assessment of RV volume is CMR. It has better near-field resolution than echo and excellent contrast between the blood pool and the myocardium. CMR is more suitable to the irregular geometry of the RV. The objectives of this study are (1) to assess ventricular volumes in the fasting state and after oral hydration in order to assess the effect of fluid status on ventricular volumes as measured by CMR; (2) to evaluate the effect of hydration on ventricular volumes compared the effect of with inter-observer and intra-observer variability, and; (3) to evaluate the effects of chamber volume on chamber deformation, including strain and peak strain rate. This study hypothesizes that (1) hydration status has an effect on right and left heart volumes, measured by CMR in healthy volunteers; (2) the effect of volume status will be a more significant contributor to variability in RV volumetry than that of inter-observer variability and intra-observer variability, and; (3) atrial and Ventricular deformation corrected for chamber size or volume is more accurate than when uncorrected for volume.