Background: Cardiac magnetic resonance (CMR) accurately quantifies right ventricular (RV) and left ventricular (LV) volumes and function. Limited availability of CMR and increasing use of MR-incompatible cardiovascular devices underscore the potential utility of cardiac computed tomography (CT) for ventricular quantification. This study quantified biventricular size and systolic function with multi-detector row CT compared with CMR imaging.
Methods: Twenty-six subjects prospectively underwent CT and CMR examinations on a 16-detector CT and 1.5 T MR scanner, respectively; claustrophobia in one and nongated CT imaging in another precluded complete imaging in 2 subjects. Contiguous multiphase short-axis images were generated from axial CT data, and steady-state free precession cine MR produced contiguous short-axis cines. Semiautomated software generated ventricular borders to calculate volume, mass, and ejection fraction (EF) from both sets of images. Blinded observers completed quantification and wall motion analyses of 23 CMR and CT data sets independently.
Results: All measures of LV size and function by cardiac CT correlated well with CMR over a wide range of LV function (LVEF 30%-72% by CMR), including end-diastolic volume (r = 0.97), end-systolic volume (r = 0.97), EF (r = 0.97), and mass (r = 0.95). Of 24 cases, 6 had inadequate contrast opacification of the RV precluding RV segmentation. In the remaining 18 CMR-CT data pairs, RVEF showed moderate agreement (r = 0.86), and RV volumes correlated well (r = 0.97 and 0.94 for RV end-diastolic volume and RV end-systolic volume, respectively). Ten percent of LV segments visualized by CT were inadequate for wall motion assessment due to motion artifact or inadequate contrast between myocardium and endocardium. For segments adequately visualized by both techniques, the mean kappa statistic was 0.88 (range 0.78-1.0), consistent with good agreement.
Conclusion: Cardiac CT accurately quantifies LV size and function; RV quantification with cardiac CT requires optimized contrast opacification of the RV.