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 (R1) 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 (R1) 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 R1. 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.
(c) 2008 Wiley-Liss, Inc.