Validation of Right Ventricular Volume Measurements by Magnetic Resonance Imaging in Small Hearts Using a Fetal Lamb Model

RATIONALE AND OBJECTIVES.Cine-magnetic resonance (MR) imaging is established as an accurate method of determining cardiac ventricular volumes in adults but has not been validated for the smaller ventricular volumes found in infants. The purpose of the authors study was to evaluate the accuracy and reproducibility of MR imaging to measure small ventricle volumes. METHODS.The volume of silicone-rubber casts of the right ventricle of 11 fetal lamb hearts was measured by MR imaging using different imaging planes and slice section thicknesses and by water displacement. RESULTS.The ventricle volumes of the 11 hearts ranged from 0.45 to 3.00 mL. Accurate and reproducible values for the right ventricle volumes were obtained by MR imaging. Thin sections (3 mm) in the axial plane produced the best results. CONCLUSIONS.Based on studies in the nonmoving heart, MR imaging can accurately measure the small ventricular volumes expected in infants.