OC14.05: Fetal cardiac MR imaging with cardiac triggering in the sheep fetus: preliminary results

Abstract

thickness = 5 mm, FOV 240 mm × 240 mm and a matrix of 128 × 128. The voxel size was 1.9 mm × 1.9 mm × 5.0 mm. Two b-values (0 and 1000) were chosen along three orthogonal directions. Apparent diffusion coefficient (ADC) maps were created using assigned b-values. Offline software was used to manually trace ADC maps of fetal lung (Osirix). Simple linear regression was performed with Pearson correlation coefficient. Interand intraexaminer bias and 95% limits of agreement (LOA) were determined using Bland–Altman plots. Results: Forty-seven scans were performed at 26.8 ± 4.6 weeks (1 SD). The median coefficient of variation for ADC was 5.6% [IQR 4.0-8.1%]. No differences in ADC values were found between either lung. Hence, subsequent analysis was based on manual tracing of the largest arbitrary image slice of the right lung. ADC values were not significantly correlated with either total lung volume (r2 = 0.0001, p = 0.94, n.s) or menstrual age (r2 = 0.003, p = 0.70, n.s). The mean ADC value was 1.75 [95% CI, 1.63-1.86]. Intra-examiner bias was −0.15 ± 2.3 [95% limits of agreement, −4.7 to +4.4]. Inter-examiner bias was 2.2 ± 3.5 [95% limit of agreement, −4.7 to +9.1]. Conclusion: ADC measurements from the fetal lung are reproducible between blinded examiners and are independent of menstrual age, as well as lung volume.