Englund Erin K, Fujiwara Takashi, Smith Sarah A, Meyers Mariana L, Friesen Richard M, Browne Lorna P, Barker Alex J
From the Departments of Radiology (E.K.E., T.F., M.L.M., L.P.B., A.J.B.), Pediatrics-Cardiology (R.M.F.), and Bioengineering (A.J.B.), University of Colorado Anschutz Medical Campus, 13123 E 16th Ave B125, Aurora, CO 80045; and Department of Radiology, Children's Hospital Colorado, Aurora, Colo (S.A.S., A.J.B.).
Radiol Cardiothorac Imaging. 2024 Dec;6(6):e240119. doi: 10.1148/ryct.240119.
Purpose To provide reference values for four-dimensional (4D) flow MRI in healthy fetuses and evaluate reliability of fetal 4D flow MRI hemodynamics in third trimester fetuses with normal cardiovascular development or suspected coarctation of the aorta (CoA). Materials and Methods Pregnant patients with healthy fetuses or fetuses with echocardiographic concern for CoA were prospectively recruited between May 2021 and October 2023. Doppler US-gated fetal 4D flow MRI was performed at 3 T. Repeated 4D flow (time permitting) and two-dimensional (2D) phase contrast (PC) MRI data were acquired. Net flow was quantified, and the reliability of 4D flow measurement was evaluated by using precision across adjacent measurement planes, internal consistency based on conservation of mass, comparison of net flow from 4D flow MRI versus 2D PC MRI, and repeatability of 4D flow from separate acquisitions. Results Data were obtained in 34 pregnant participants (mean maternal age, 33 years ± 5 [SD]; mean gestational age, 35 weeks ± 2; = 22 healthy fetuses and 12 fetuses with suspected CoA). Precision was high across all vascular segments (mean within-subject coefficient of variation = 7%). For mass conservation, there was an average difference of 19% ± 12 between ductus arteriosus plus isthmus flow versus descending aorta flow ( = 0.76). Net flow measured with 4D flow MRI correlated with that measured with 2D PC MRI ( = 0.51) but was underestimated relative to 2D PC MRI by approximately 34%. Hemodynamic parameters quantified from repeated 4D flow acquisitions had good agreement, with an intraclass correlation coefficient of 0.94 between test and retest data. Conclusion Hemodynamic measurements derived from fetal 4D flow MRI were reliable, showing good internal consistency, precision, and repeatability; however, as expected, 4D flow MRI underestimated absolute blood flow relative to 2D PC MRI. Fetal MRI, Cardiac, Aorta, Hemodynamics/Flow Dynamics, Pulmonary Arteries © RSNA, 2024.
目的 提供健康胎儿四维（4D）血流磁共振成像（MRI）的参考值，并评估孕晚期心血管发育正常或疑似主动脉缩窄（CoA）胎儿的胎儿4D血流MRI血流动力学的可靠性。材料与方法 在2021年5月至2023年10月期间前瞻性招募了怀有健康胎儿或超声心动图检查怀疑患有CoA的胎儿的孕妇。在3T条件下进行多普勒超声门控胎儿4D血流MRI检查。获取重复的4D血流（时间允许时）和二维（2D）相位对比（PC）MRI数据。对净流量进行量化，并通过相邻测量平面间的精度、基于质量守恒的内部一致性、4D血流MRI与2D PC MRI的净流量比较以及单独采集的4D血流的可重复性来评估4D血流测量的可靠性。结果 34名孕妇参与研究（平均母亲年龄33岁±5[标准差]；平均孕周35周±2；22例为健康胎儿，12例为疑似CoA胎儿）。所有血管段的精度都很高（平均受试者内变异系数=7%）。对于质量守恒，动脉导管加峡部血流与降主动脉血流之间的平均差异为19%±12（P=0.76）。4D血流MRI测量的净流量与2D PC MRI测量的净流量相关（P=0.51），但相对于2D PC MRI低估了约34%。从重复的4D血流采集中量化的血流动力学参数具有良好的一致性，测试和复测数据之间的组内相关系数为0.94。结论 胎儿4D血流MRI得出的血流动力学测量结果可靠，显示出良好的内部一致性、精度和可重复性；然而，正如预期的那样，相对于2D PC MRI，4D血流MRI低估了绝对血流量。胎儿MRI、心脏、主动脉、血流动力学/流动动力学、肺动脉 ©RSNA，2024
