Abstract 260: Quantitative Evaluation of Right Ventricular Volume and Its Ejection Fraction by 320 Slice Computed Tomography Compared With Three Dimensional Echocardiogram
Purpose: To evaluate efficacy and reproducibility of 320 slice CT for measuring right ventricular (RV) end diastolic (RVEDV) and systolic volume (RVESV), we compared CT with three dimensional (3D) transthoracic echocardiogram (TTE).
Methods: RVEDV and RVESV (ml), and RV ejection fraction (EF) (%) were assessed in 21 consecutive patients (15 male, 60±15 yrs) using retrospective ECG gated CT (Aquilion One) and 3D TTE (IE-33). CT Images were reconstructed every 5% from 0 –95% of the R-R interval, and a semi automated 3D segmentation technique (ADW 4.5) was applied. Maximum and minimum volumes were regarded as RVEDV and RVESV and RVEF was calculated as RVEDV-RVESV/RVEDV ×100.
Results: Mean±SD of RVEDV was 135.2±49.4 ml by CT and 90.6±22.1ml by TTE. RVESV was 86.0±37.7ml by CT and 53.8±19.3 ml by TTE and RVEF was 39.8±9.4% by CT and 41.3±9.8% by TTE. The correlation coefficient (CC) between CT and TTE in RVEDV, RVESV, and RVEF were 0.586, 0.805 and 0.437. Mean difference±1.96SD of RVEDV, RVESV and RVEF by the Bland and Altman analysis calculated from CT minus TTE was 44.6±79.5ml, 32.2±49.0ml and −1.5±20.0ml, respectively. CCs of interobserver variation were 0.84 in CT and 0.86 in TTE (RVEDV), 0.89 in CT and 0.85 in TTE (RVESV), and 0.59 in CT and 0.61 in TTE (RVEF).
Conclusions: Interobserver reproducibility of 3D CT for measuring RV volume was nearly equal to 3D TTE. The absolute value of RV volume by CT was approximately 45ml larger than by TTE (RVEDV), and 32ml larger than by TTE (RVESV) and as a result RVEF was 2% smaller by CT than by TTE. The larger the RV size, the larger the difference between CT and TTE. This may be complex RV morphological enlargement, and 3D TTE may not allow visualization of the whole RV.