CARDIAC VOLUMETRY - COMPARISON OF ECHOPLANAR AND CONVENTIONAL CINE-MAGNETIC RESONANCE DATA-ACQUISITION STRATEGIES

RATIONALE AND OBJECTIVES. Ejection fraction (EF) measurements obtained using conventional cine-magnetic resonance imaging (MRI) are accurate but time-consuming, With echoplanar imaging (EPI), these data can be acquired much faster, In this study, EF and cardiac output (GO) measur ements based on EPI data are compared with those measurements based on cine-MRI images, METHODS. Twelve subjects were examined on a 1.5-T im ager equipped with a special EPI gradient system, The entire heart was imaged with contiguous axial 10-mm sections using cine-MRI and EPI te chniques, With cine-MRI, 20 frames were acquired over 256 cardiac cycl es; with EPI, 24 frames were obtained over four RR intervals using an electrocardiogram-triggered four-shot acquisition strategy, Ejection f raction and CO were calculated based on the summation of the individua l end-systolic and end-diastolic volumes, Ejection fraction and CO mea surements based on the two different data sets were compared, RESULTS. Multishot EPI was 50 times faster than cine-MRI, The short acquisitio n time permitted breath-hold imaging, The high temporal (16 to 24 fram es/RR interval) and spatial resolution (1.56 X 1.56 mm in plane) of th e multishot EPI images enabled delineation of the ventricular lumen at end-systole and end-diastole in a fashion similar to cine-MRI. Echopl anar imaging EF and CO measurements correlated well with cine-MRI EF m easurements, with correlation coefficients of 0.96 and 0.94, respectiv ely, The 95% confidence interval of the EF measurement differences bet ween the two techniques was narrow, ranging from -5.2 to 5.7 EP percen tage points, CONCLUSIONS. Accurate volumetric EF and CO measurements a re possible based on ultrafast multishot EPI data sets as part of an i ntegrated MRI-based cardiac evaluation.