Harris Birthright Research Centre, Kings College Hospital, London, UK.
Placenta. 2013 Oct;34(10):885-91. doi: 10.1016/j.placenta.2013.07.006. Epub 2013 Aug 9.
To investigate (a) if placental perfusion in the second trimester of pregnancy, measured by two non-invasive magnetic resonance imaging (MRI) techniques, is related to impedance to flow in the uterine arteries, as assessed by Doppler ultrasound; and (b) if these measures are associated with future gestational outcome.
In 37 singleton pregnancies at 24-29 weeks' gestation, uterine artery pulsatility index (PI) was measured by Doppler ultrasound and placental perfusion was measured by Arterial Spin Labelling (flow-sensitive alternating inversion recovery (FAIR)) and intravoxel incoherent motion (IVIM) echo-planar imaging at 1.5 T in basal, central and placental regions of interest. The values were compared between those delivering small for gestational age (SGA) and appropriate for gestational age (AGA) neonates.
In 23 pregnancies that resulted in delivery of SGA neonates, compared to the 14 with AGA neonates, the median basal FAIR measure was significantly lower (923.0 vs. 2359.0 arbitrary units; p = 0.003) as were IVIM measures of perfusing fraction (f) in basal, central and whole-placental regions (37.8 vs. 40.7%; p = 0.046; 24.3 vs. 35.1%; p = 0.014 and 27.9% vs. 36.2%; p = 0.001, respectively). In the SGA group, the median uterine artery PI was increased (1.96 vs. 1.03; p = 0.001). There were significant associations between uterine artery PI and placental perfusion assessed by both FAIR and IVIM.
Pregnancies that result in SGA neonates exhibited reduced placental perfusion as assessed by MRI during the second trimester. This measurement was found to be strongly associated with impedance to flow in the uterine arteries. We suggest that FAIR or IVIM MRI examinations may be used to directly and non-invasively determine placental perfusion, and that the measured values are strong indicators of future gestational outcome.
研究（a）在妊娠中期，通过两种非侵入性磁共振成像（MRI）技术测量胎盘灌注是否与通过多普勒超声评估的子宫动脉血流阻力相关；以及（b）这些测量值是否与未来的妊娠结局相关。
在 37 例 24-29 周妊娠的单胎妊娠中，通过多普勒超声测量子宫动脉搏动指数（PI），并通过动脉自旋标记（血流敏感交替反转恢复（FAIR））和体素内不相干运动（IVIM）在基础、中央和胎盘感兴趣区进行 MRI 测量。将这些值与分娩小于胎龄儿（SGA）和适于胎龄儿（AGA）新生儿的孕妇进行比较。
在 23 例分娩 SGA 新生儿的孕妇中，与 14 例分娩 AGA 新生儿的孕妇相比，基础 FAIR 中位数明显较低（923.0 与 2359.0 个任意单位；p=0.003），基础、中央和整个胎盘区域的 IVIM 灌注分数（f）测量值也较低（37.8 与 40.7%；p=0.046；24.3 与 35.1%；p=0.014 和 27.9%与 36.2%；p=0.001）。在 SGA 组中，子宫动脉 PI 的中位数升高（1.96 与 1.03；p=0.001）。子宫动脉 PI 与通过 FAIR 和 IVIM 评估的胎盘灌注之间存在显著相关性。
导致 SGA 新生儿的妊娠在妊娠中期显示出 MRI 评估的胎盘灌注减少。该测量值与子宫动脉血流阻力密切相关。我们建议，FAIR 或 IVIM MRI 检查可用于直接和无创地测量胎盘灌注，并且测量值是未来妊娠结局的强有力指标。
