Tompkins Reagan M, Fujiwara Takashi, Schrauben Eric M, Browne Lorna P, van Schuppen Joost, Clur Sally-Ann, Friesen Richard M, Englund Erin K, Barker Alex J, van Ooij Pim
Department of Radiology & Nuclear Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Department of Radiology, Section of Pediatric Radiology, Children's Hospital Colorado, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.
Magn Reson Med. 2025 May;93(5):1969-1983. doi: 10.1002/mrm.30411. Epub 2025 Jan 9.
To correct maternal breathing and fetal bulk motion during fetal 4D flow MRI.
A Doppler-ultrasound fetal cardiac-gated free-running 4D flow acquisition was corrected post hoc for maternal respiratory and fetal bulk motion in separate automated steps, with optional manual intervention to assess and limit fetal motion artifacts. Compressed-sensing reconstruction with a data outlier rejection algorithm was adapted from previous work. Pre- and post-motion correction comparison included qualitative visibility of vasculature on phase-contrast MR angiograms (five-point Likert scale), conservation of mass of the aortic isthmus, ductus arteriosus, and descending aorta, and coefficient of variation of flow along the descending aorta.
Twenty-nine third trimester acquisitions were performed for 15 healthy fetuses and two patients with postnatally confirmed aortic coarctation during a single examination for each participant. Only 15/27 (56%) of all volunteers and 1/2 (50%) of all patient precorrection acquisitions were suitable for flow analysis. Motion correction recovered eight "failed" acquisitions, including one patient, with 24/29 (83%) suitable for flow analysis. In the 15 viable uncorrected volunteer acquisitions, motion correction improved phase-contrast MR angiograms visibility significantly in the ductus arteriosus (from 4.0 to 4.3, p = 0.04) and aortic arch (3.7 to 4.0, p = 0.03). Motion correction improved conservation of mass to a median (interquartile range) percent difference of 5% (9%) from 14% (24%) with improvement shown in 14/15 acquisitions (p = 0.002), whereas coefficient of variation changes were not significantly different (uncorrected: 0.15 (0.09), corrected: 0.11 (0.09), p = 0.3).
Motion correction compensated for maternal and fetal motion in fetal 4D flow MRI data, improving image quality and conservation of mass.
校正胎儿四维血流磁共振成像（MRI）过程中母体呼吸和胎儿整体运动。
采用多普勒超声胎儿心脏门控自由运行四维血流采集，在事后通过单独的自动化步骤校正母体呼吸和胎儿整体运动，并可选择手动干预以评估和限制胎儿运动伪影。采用数据异常值剔除算法的压缩感知重建是基于先前的工作改编而来。运动校正前后的比较包括相位对比磁共振血管造影上血管系统的定性可见性（五点李克特量表）、主动脉峡部、动脉导管和降主动脉的质量守恒以及降主动脉血流的变异系数。
对15名健康胎儿和2名出生后确诊为主动脉缩窄的患者在每次检查期间进行了29次孕晚期采集。所有志愿者中只有15/27（56%）以及所有患者校正前采集中的1/2（50%）适合进行血流分析。运动校正挽救了8次“失败”采集，包括1名患者，其中24/29（83%）适合进行血流分析。在15次可行的未校正志愿者采集中，运动校正显著改善了动脉导管（从4.0提高到4.3，p = 0.04）和主动脉弓（从3.7提高到4.0，p = 0.03）相位对比磁共振血管造影的可见性。运动校正将质量守恒改善至中位数（四分位间距）百分比差异，从未校正时的14%（24%）降至5%（9%），14/15次采集显示有改善（p = 0.002），而降主动脉血流变异系数的变化无显著差异（未校正：0.15（0.09），校正后：0.11（0.09），p = 0.3）。
运动校正补偿了胎儿四维血流MRI数据中的母体和胎儿运动，提高了图像质量和质量守恒。
