Evaluation of myocardial volume heterogeneity during end-diastole and end-systole using cine MRI.

The aim of this study was to examine the difference in the myocardial volume between end-diastole and end-systole in 24 human volunteers, using steady-state free precession gradient-echo cine imaging of both long- and short-axis views of the left ventricle and a newly developed three-dimensional (3D) analysis method. In addition, we examined retrospectively the cine magnetic resonance imaging (MRI) studies from 20 of the subjects that included a stack of short-axis views, from base to apex, suitable for a standard two-dimensional (2D) analysis. With the 3D analysis method, no significant variance in the myocardial volume was found (mean difference=0.1%+/-9.1%, p=0.88) between end-diastole (ED) and end-systole (ES), while the 2D technique yielded significantly larger values for the LV myocardial volume at ES than ED (mean difference=14.7%+/-16.8%, p<0.0001). ED myocardial volumes correlated closely in subjects belonging to both groups (3D: 122.81+/-27.58 mL vs. 2D: 129.0+/-37.21 mL, p=0.29), while the 2D myocardial volumes were significantly larger at ES (3D: 123.01+/-28.65 mL vs. 2D: 150.47+/-47.29 mL, p=0.002). The findings of this study support the notion that myocardial volume does not change during the cardiac cycle and any discrepancies between muscle volume at ED and ES can be eliminated by exact tracking of the mitral valve plane over the cardiac cycle, using a generalized, 3D analysis method that includes long-axis views of the heart.