宫内炎症小鼠模型中胎盘解剖结构和灌注的体内评估。
In vivo assessment of the placental anatomy and perfusion in a mouse model of intrauterine inflammation.
机构信息
Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Department of Gynecology and Obstetrics, Division of Maternal Fetal Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
出版信息
J Magn Reson Imaging. 2018 May;47(5):1260-1267. doi: 10.1002/jmri.25867. Epub 2017 Oct 5.
BACKGROUND
Magnetic resonance imaging (MRI) provides useful markers to examine placental function. MRI features of placental injury due to intrauterine inflammation-a common risk during pregnancy, are not well known.
PURPOSE
To investigate the capability of structural MRI and intravoxel incoherent motion (IVIM) imaging in examining acute placental injury in a mouse model of intrauterine inflammation, as well as gestation-dependent placental changes.
STUDY TYPE
Prospective study.
ANIMAL MODEL
Pregnant CD1 mice were scanned on embryonic day 15 (E15, n = 40 placentas from six dams) and E17. On E17, mice were subjected to intrauterine injury by exposure to lipopolysaccharide (LPS, n = 25 placentas from three dams) or sham injury (n = 25 placentas from three dams).
FIELD STRENGTH/SEQUENCE: In vivo MRI was performed on an 11.7T Bruker scanner, using a fast spin-echo sequence and a diffusion-weighted echo-planar imaging (EPI) sequence.
ASSESSMENT
T -weighted MRI was acquired to evaluate placental volume. IVIM imaging was performed in a restricted field-of-view using 15 b-values from 10-800 s/mm , based on which, the pseudodiffusion fraction (f), pseudodiffusion coefficient (D*), and tissue water coefficient (D) were estimated with a two-step fitting procedure.
STATISTICAL TESTS
Two-way analysis of variance (ANOVA) was used to evaluate the group differences.
RESULTS
The placental volume increased by ∼21% from E15 to E17 (P < 0.01), and a 15% volume loss was observed at 6 hours after LPS exposure (P < 0.01). IVIM parameters (f, D*, and f·D*) were similar between the E15 and E17 sham groups (P > 0.05), which was significantly reduced in the LPS-exposed placentas compared to the shams (P < 0.001). D values decreased from E15 to E17 (P < 0.05), which were further reduced after LPS exposure (P < 0.05). Changes in placental area and vascular density were histologically identified in the LPS-exposed group, along with gestation-dependent changes.
DATA CONCLUSION
Our results suggested structural MRI and IVIM measurements are potential markers for detecting acute placental injury after intrauterine inflammation.
LEVEL OF EVIDENCE
1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1260-1267.
背景
磁共振成像（MRI）提供了有用的标记物来检查胎盘功能。由于宫内炎症（怀孕期间常见的风险）导致的胎盘损伤的 MRI 特征尚不清楚。
目的
研究结构 MRI 和体素内不相干运动（IVIM）成像在检查宫内炎症小鼠模型中急性胎盘损伤以及与妊娠相关的胎盘变化的能力。
研究类型
前瞻性研究。
动物模型
在胚胎第 15 天（E15，来自六只母鼠的 40 个胎盘）和 E17 对怀孕的 CD1 小鼠进行扫描。在 E17 时，通过暴露于脂多糖（LPS，来自三只母鼠的 25 个胎盘）或假损伤（来自三只母鼠的 25 个胎盘）使小鼠宫内受伤。
磁场强度/序列：在 11.7T Bruker 扫描仪上进行体内 MRI，使用快速自旋回波序列和扩散加权回波平面成像（EPI）序列。
评估
采集 T2 加权 MRI 以评估胎盘体积。在受限的视野内使用 10-800 s/mm 的 15 个 b 值进行 IVIM 成像，根据该成像结果，使用两步拟合程序估计假扩散分数（f）、假扩散系数（D*）和组织水系数（D）。
统计学检验
使用双向方差分析（ANOVA）评估组间差异。
结果
从 E15 到 E17，胎盘体积增加了约 21%（P < 0.01），在 LPS 暴露后 6 小时观察到 15%的体积损失（P < 0.01）。E15 和 E17 假损伤组之间的 IVIM 参数（f、D*和 f·D*）相似（P > 0.05），与假损伤组相比，LPS 暴露的胎盘显著降低（P < 0.001）。D 值从 E15 到 E17 降低（P < 0.05），在 LPS 暴露后进一步降低（P < 0.05）。LPS 暴露组的胎盘面积和血管密度发生了组织学变化，同时还发生了与妊娠相关的变化。
数据结论
我们的结果表明，结构 MRI 和 IVIM 测量可能是检测宫内炎症后急性胎盘损伤的潜在标志物。
证据水平
1 技术功效：第 2 阶段 J. Magn. Reson. Imaging 2018;47:1260-1267.
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