Segmentation of cardiac cine MR images of left and right ventricles : interactive semiautomated methods and manual contouring by two readers with different education and experience

Purpose: To test interactive semiautomated methods (ISAM) vs. manual contouring (MC) in segmenting cardiac cine MR images. Materials and Methods: Short-axis images of 10 consecutive patients (1.5-81.5 years of age) were evaluated by a trained radiologist (Rl) and a low-trained engineer (R2). Each of them performed four independent reading sessions: two using ISAM and two using MC. Left ventricle (LV) myocardial mass (LVMM), LV ejection fraction (LVEF), and right ventricle (RV) ejection fraction (RVEF) were obtained. Bland-Altman analysis and Wilcoxon test were used. Results: The bias ± 2 standard deviations (SD) of ISAM vs. MC for LVMM (g) was -5.7 ± 13.4 (Rl) and-5.5 ± 26.3 (R2); for LVEF (%) it was -1.4 ± 13.0 and -2.9 ± and 6.8; for RVEF (%) it was 2.6 ± 17.0 and 1.0 ± 16.7. Considering both readers/methods, intraobserver bias ± 2 SD ranged from 0.3 ± 25.3 to -6.8 ± 23.0, from 0.2 ± 8.0 to -4.4 ± 15.8, and from -0.0 ± 26.4 to -4.6 ± 27.8, respectively. Interobserver bias ± 2 SD was -25.9 ± 46.0 (ISAM) and 26.1 ± 36.4 (MC), -1.4 ± 8.6 (ISAM) and 0.1 ± 17.9 (MC), and 0.7 ± 23.3 and 2.3 ± 29.8, respectively. Larger SDs were systematically found for RVEF vs. LVEF. Segmentation times: five minutes for LV with ISAM (both readers); for LV with MC, six (R1) vs. nine minutes (R2) (P < 0.001); five to six minutes for RV (both methods /readers). R2 significantly reduced LV segmentation times from nine (MC) to five minutes (ISAM) (P < 0.001). Conclusion: A highly reproducible LV segmentation was performed in a short time by Rl. The advantage of ISAM vs. MC for LV segmentation was a time saving only for R2. For RVEF, a lower reproducibility was observed for both methods and readers.