ObjectiveTo utilise combined diffusion‐relaxation MRI techniques to interrogate antenatal changes in the placenta prior to extreme preterm birth among both women with PPROM and membranes intact, and compare this to a control group who subsequently delivered at term.DesignObservational study.SettingTertiary Obstetric Unit, London, UK.PopulationCases: pregnant women who subsequently spontaneously delivered a singleton pregnancy prior to 32 weeks' gestation without any other obstetric complications. Controls: pregnant women who delivered an uncomplicated pregnancy at term.MethodsAll women consented to an MRI examination. A combined diffusion‐relaxation MRI of the placenta was undertaken and analysed using fractional anisotropy, a combined T2*‐apparent diffusion coefficient model and a combined T2*‐intravoxel incoherent motion model, in order to provide a detailed placental phenotype associated with preterm birth. Subgroup analyses based on whether women in the case group had PPROM or intact membranes at time of scan, and on latency to delivery were performed.Main Outcome MeasuresFractional anisotropy, apparent diffusion coefficients and T2* placental values, from two models including a combined T2*‐IVIM model separating fast‐ and slow‐flowing (perfusing and diffusing) compartments.ResultsThis study included 23 women who delivered preterm and 52 women who delivered at term. Placental T2* was lower in the T2*‐apparent diffusion coefficient model (p < 0.001) and in the fast‐ and slow‐flowing compartments (p = 0.001 and p < 0.001) of the T2*‐IVIM model. This reached a higher level of significance in the preterm prelabour rupture of the membranes group than in the membranes intact group. There was a reduced perfusion fraction among the cases with impending delivery.ConclusionsPlacental diffusion‐relaxation reveals significant changes in the placenta prior to preterm birth with greater effect noted in cases of preterm prelabour rupture of the membranes. Application of this technique may allow clinically valuable interrogation of histopathological changes before preterm birth. In turn, this could facilitate more accurate antenatal prediction of preterm chorioamnionitis and so aid decisions around the safest time of delivery. Furthermore, this technique provides a research tool to improve understanding of the pathological mechanisms associated with preterm birth in vivo.

中文翻译：

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妊娠 <32 周自发性早产前的胎盘多模态 MRI：一项观察性研究


目的利用联合弥散弛豫 MRI 技术来询问未足月胎膜早破且胎膜完整的妇女在极端早产前胎盘的产前变化，并将其与随后足月分娩的对照组进行比较。设计观察性研究。设置伦敦第三产科单位，英国。人口案例：随后在妊娠 32 周之前自然分娩单胎妊娠且没有任何其他产科并发症的孕妇。对照：足月妊娠且无并发症的孕妇。方法所有妇女均同意接受 MRI 检查。为了提供与早产相关的详细胎盘表型，使用分数各向异性、组合 T2* 表观扩散系数模型和组合 T2*- 象素内不相干运动模型对胎盘进行组合扩散松弛 MRI 和分析。根据病例组中的女性在扫描时和分娩潜伏期是否有未胎膜早破或完整胎膜进行亚组分析。主要结果指标来自两个模型（包括组合 T2*）的分数各向异性、表观扩散系数和 T2* 胎盘值‐IVIM 模型分离快流和慢流（灌注和扩散）室。结果本研究包括 23 名早产妇女和 52 名足月分娩妇女。在 T2* 表观扩散系数模型中，胎盘 T2* 较低（ p < 0.001) 以及快流和慢流区室 ( p = 0.001 和p < 0.001) 的 T2*-IVIM 模型。与胎膜完整组相比，早产胎膜破裂组的显着性更高。 即将分娩的病例中灌注分数降低。结论胎盘弥散舒张揭示了早产前胎盘的显着变化，在早产胎膜破裂的病例中观察到更大的影响。该技术的应用可以在早产前对组织病理学变化进行具有临床价值的询问。反过来，这可以促进对早产绒毛膜羊膜炎进行更准确的产前预测，从而有助于决定最安全的分娩时间。此外，该技术提供了一种研究工具，以提高对体内早产相关病理机制的理解。