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The purpose was to compare global left-ventricular (LV) function parameters measured with cine MRI with results from multiphase dual-source CT (DSCT) using 10 and 20 reconstruction phases. Twenty-eight patients with suspected or known CAD underwent DSCT coronary angiography. LV end-diastolic (EDV), end-systolic (ESV) and stroke volumes (SV), and ejection fraction (EF) were determined using LV segmentation and selection of specific phases from DSCT image sets reconstructed either at 5% or 10% steps through the R-R interval. Cine MRI served as the reference investigation. Threshold-based 3D-segmentation was feasible in all DSCT data sets. EDV and ESV were underestimated by DSCT, but showed excellent correlation (Pearson's correlation coefficient 0.95/0.97) to values obtained with MRI. Using data from 5% DSCT image reconstructions instead of 10% phase reconstructions, the position of the ED and ES phase was changed in 16 of 28 patients; ESVs were to found to be slightly smaller, whereas EDV were slightly larger, resulting in a systematic overestimation of LV EF by 1.9% (p=0.56). Threshold-based 3D segmentation enables accurate and reliable DSCT determination of global LV function with excellent correlation to cine MRI. Minor differences in LV EF indicate that both modalities are virtually interchangeable, even if the number of reconstructed phases is limited to 10% phase reconstructions.

Objective: The purpose of this study was to evaluate software for threshold-based 3D segmentation of the left ventricle in comparison with traditional 2D short axis-based planimetry (Simpson method) for measurement of left ventricular (LV) volume and global function with state-of-the-art dual-source CT., Subjects and Methods: Fifty patients with known or suspected coronary artery disease underwent coronary CT angiography. LV end-diastolic, end-systolic, and stroke volumes and ejection fraction were determined from axial images to which 3D segmentation had been applied and from short-axis reformations from 2D planimetry. Interobserver variability was assessed for both approaches., Results: Threshold-based 3D LV segmentation had excellent correlation with 2D short-axis results (end-diastolic volume, R = 0.99; end-systolic volume, R = 0.99; stroke volume, R = 0.90; ejection fraction, R = 0.97; p < 0.0001). Bland-Altman analyses revealed systematic underestimation of LV end-diastolic volume (-7.4 +/- 8.9 mL) and LV end-systolic volume (-7.0 +/- 4.4 mL) with the 3D segmentation approach and 2.8 +/- 3.3% overestimation of LV ejection fraction. Interobserver variation with 3D segmentation analysis was significantly (p < 0.001) less (e.g., LV ejection fraction, 0.1 +/- 1.7%) than with the 2D technique, and mean analysis time was significantly shorter (172 +/- 20 vs 248 +/- 29 seconds; p < 0.05)., Conclusion: Automated threshold-based 3D segmentation enables accurate and reproducible dual-source CT assessment of LV volume and function with excellent correlation with results of 2D short-axis analysis. Exclusion of papillary muscles from LV volume results in small systematic differences in quantitative values.