Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, USA.
Wisconsin National Primate Center, University of Wisconsin - Madison, Madison, Wisconsin, USA.
J Magn Reson Imaging. 2019 Feb;49(2):534-545. doi: 10.1002/jmri.26206. Epub 2018 Aug 13.
Pregnancy complications are often associated with poor uteroplacental vascular adaptation and standard diagnostics are unable to reliably quantify flow in all uteroplacental vessels and have poor sensitivity early in gestation.
To investigate the feasibility of using 4D flow MRI to assess total uteroplacental blood flow in pregnant rhesus macaques as a precursor to human studies.
Retrospective feasibility study.
Fifteen healthy, pregnant rhesus macaques ranging from the 1 trimester to 3 trimester of gestation.
FIELD STRENGTH/SEQUENCE: Abdominal 4D flow MRI was performed on a 3.0T scanner with a radially undersampled phase contrast (PC) sequence. Reference ferumoxytol-enhanced angiograms were acquired with a 3D ultrashort echo time sequence with a center-out radial trajectory.
Repeatability of flow measurements was assessed with scans performed same-day and on consecutive days in the uterine arteries and ovarian veins. In-flow was compared against out-flow in the uterus, umbilical cord, and fetal heart with a conservation of mass analysis. Conspicuity of uteroplacental vessels was qualitatively compared between PC angiograms derived from 4D flow data and ferumoxytol-enhanced angiograms.
Bland-Altman analysis was used to quantify same-day and consecutive-day repeatability.
Same-day flow measurements showed an average difference between scans of 13% in both the uterine arteries and ovarian veins, while consecutive-day measurements showed average differences of 22% and 24%, respectively. Comparisons of in-flow and out-flow showed average differences of 15% in the uterus, 8% in fetal heart, and 15% in the umbilical cord. PC angiograms showed similar depiction of main uteroplacental vessels as high-resolution, ferumoxytol-enhanced angiograms.
4D flow MRI could be used in the rhesus macaque for repeatable flow measurements in the uteroplacental and fetal vasculature, setting the stage for future human studies.
2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:534-545.
妊娠并发症通常与不良的胎盘血管适应有关，而标准诊断无法可靠地量化所有胎盘血管的血流，并且在妊娠早期的敏感性较差。
研究使用 4D 流动 MRI 评估怀孕恒河猴总胎盘血流的可行性，作为人类研究的前奏。
回顾性可行性研究。
15 只健康的怀孕恒河猴，处于妊娠 1 至 3 个孕期。
磁场强度/序列：在 3.0T 扫描仪上进行腹部 4D 流动 MRI 检查，采用径向欠采样相位对比（PC）序列。使用 3D 超短回波时间序列和中心向外的径向轨迹采集参考 Ferumoxytol 增强血管造影。
在子宫动脉和卵巢静脉中，同一天和连续几天进行扫描，评估流量测量的重复性。采用质量守恒分析比较子宫、脐带和胎儿心脏的流入量和流出量。定性比较从 4D 流动数据得出的 PC 血管造影和 Ferumoxytol 增强血管造影之间胎盘血管的显影效果。
Bland-Altman 分析用于量化同一天和连续天的重复性。
同一天的血流测量显示，在子宫动脉和卵巢静脉中，两次扫描的平均差异分别为 13%，而连续两天的测量结果分别为 22%和 24%。流入量和流出量的比较显示，子宫、胎儿心脏和脐带的平均差异分别为 15%、8%和 15%。PC 血管造影显示主要胎盘血管的显影与高分辨率 Ferumoxytol 增强血管造影相似。
4D 流动 MRI 可用于恒河猴，以重复测量胎盘和胎儿血管的血流，为未来的人类研究奠定基础。
2 技术功效：阶段 1 J. Magn. Reson. Imaging 2019;49:534-545.
