Determination of left ventricular volumes and ejection fraction by nuclear magnetic resonance imaging

Abstract

To determine the ability of nuclear magnetic resonance (NMR) imaging to assess left ventricular (LV) volumes and ejection fraction (EF), we studied 24 patients within 48 hours of single-plane LV angiography. In all patients, a transverse, single-plane NMR acquisition technique was employed with LV end-diastolic (ED) and end-systolic (ES) volumes (V) calculated by a modified area-length algorithm. In nine patients, a multislice acquisition technique was employed with LVEDV and LVESV calculated by a Simpson's rule algorithm. NMR-determined LVV and EF correlated reasonably well with angiographic values (LVEDV: r = 0.75; LVESV: r = 0.90; and LVEF: r = 0.76). The single-plane NMR technique significantly underestimated LVEDV (p less than 0.01), whereas no significant difference was demonstrated for LVESV. As a result, angiographic LVEF was significantly underestimated (p less than 0.05). This underestimation is likely related to off-axis imaging and to the geometric constraints of a single-plane algorithm. In comparing multislice NMR to angiographic data, no significant difference was demonstrated for LVEDV, LVESV, or LVEF. Thus, quantitation of LVV and EF with NMR is feasible, and comparison to angiographic volumes is similar to results reported from other noninvasive imaging modalities. Improvement in current acquisition techniques and software should result in further quantitative potential.