MR image analysis: Longitudinal cardiac motion influences left ventricular measurements.

BACKGROUND: Software for the analysis of left ventricular (LV) volumes and mass using border detection in short-axis images only, is hampered by through-plane cardiac motion. Therefore we aimed to evaluate software that involves longitudinal cardiac motion.

METHODS: Twenty-three consecutive patients underwent 1.5-Tesla cine magnetic resonance (MR) imaging of the entire heart in the long-axis and short-axis orientation with breath-hold steady-state free precession imaging. Offline analysis was performed using software that uses short-axis images (Medis MASS) and software that includes two-chamber and four-chamber images to involve longitudinal LV expansion and shortening (CAAS-MRV). Intraobserver and interobserver reproducibility was assessed by using Bland-Altman analysis.

RESULTS: Compared with MASS software, CAAS-MRV resulted in significantly smaller end-diastolic (156+/-48ml versus 167+/-52ml, p=0.001) and end-systolic LV volumes (79+/-48ml versus 94+/-52ml, p<0.001). In addition, CAAS-MRV resulted in higher LV ejection fraction (52+/-14% versus 46+/-13%, p<0.001) and calculated LV mass (154+/-52g versus 142+/-52g, p=0.004). Intraobserver and interobserver limits of agreement were similar for both methods.

CONCLUSION: MR analysis of LV volumes and mass involving long-axis LV motion is a highly reproducible method, resulting in smaller LV volumes, higher ejection fraction and calculated LV mass.