Millischer A E, Deloison B, Silvera S, Ville Y, Boddaert N, Balvay D, Siauve N, Cuenod C A, Tsatsaris V, Sentilhes L, Salomon L J
Service de Radiologie, Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France.
Service de Gynécologie-Obstétrique, Hôpital Necker Enfants Malades, Assistance Publique hôpitaux de Paris, Paris, France.
Placenta. 2017 May;53:40-47. doi: 10.1016/j.placenta.2017.03.006. Epub 2017 Mar 10.
Ultrasound (US) is the primary imaging modality for the diagnosis of placenta accreta, but it is not sufficiently accurate. MRI morphologic criteria have recently emerged as a useful tool in this setting, but their analysis is too subjective. Recent studies suggest that gadolinium enhancement may help to distinguish between the stretched myometrium and placenta within a scar area. However, objective MRI criteria are still required for prenatal diagnosis of placenta accreta. The purpose of this study was to assess the diagnostic value of dynamic contrast gadolinium enhancement (DCE) MRI patterns for placenta accreta.
MR images were acquired with a 1.5-T unit at 30-35 weeks of gestation in women with a history of Caesarian section, a low-lying anterior placenta, and US features compatible with placenta accreta. Sagittal, axial and coronal SSFP (Steady State Free Precession) sequences were acquired before injection. Then, contrast-enhanced dynamic T1-weighted images were acquired through the entire cross-sectional area of the placenta. Images were obtained sequentially at 10- to 14-s intervals for 2 min, beginning simultaneously with the bolus injection. Functional analysis was performed retrospectively, and tissular relative enhancement parameters were extracted from the recorded images. The suspected area of accreta (SAA) was placed in the region of the previous scar, and a control area (CA) of similar size was placed on the same image plane, as far as possible from the SAA. Semi-quantitative analysis of DCE-MR images was based on the kinetic enhancement curves in these two regions of interest (ROI). Three tissular relative enhancement parameters were compared according to the pregnancy outcomes, namely time to peak, maximal signal intensity, and area under the enhancement curve.
We studied 9 women (43%) with accreta and 12 women (57%) with a normal placenta. All three tissular relative enhancement parameters differed significantly between the two groups (p < 10).
The use of dynamic contrast-enhanced MRI at 30-35 weeks of gestation in women with a high risk of placenta accreta allows the extraction of tissular enhancement parameters that differ significantly between placenta accreta and normal placenta. It therefore provides objective parameters on which to base the diagnosis and patient management.
超声（US）是诊断胎盘植入的主要影像学检查方法，但准确性欠佳。MRI形态学标准最近已成为这方面的有用工具，但其分析过于主观。近期研究表明，钆增强可能有助于区分瘢痕区域内伸展的子宫肌层和胎盘。然而，胎盘植入的产前诊断仍需要客观的MRI标准。本研究的目的是评估动态对比钆增强（DCE）MRI模式对胎盘植入的诊断价值。
对有剖宫产史、前置胎盘且超声特征符合胎盘植入的孕妇，在妊娠30 - 35周时用1.5-T设备采集MR图像。注射前采集矢状位、轴位和冠状位稳态自由进动（SSFP）序列。然后，通过胎盘的整个横截面积采集对比增强动态T1加权图像。从团注开始同时，以10 - 14秒的间隔连续采集2分钟图像。进行回顾性功能分析，并从记录图像中提取组织相对增强参数。将疑似植入区域（SAA）置于先前瘢痕区域，在同一图像平面上放置一个大小相似的对照区域（CA），尽可能远离SAA。DCE-MR图像的半定量分析基于这两个感兴趣区域（ROI）的动态增强曲线。根据妊娠结局比较三个组织相对增强参数，即达峰时间、最大信号强度和增强曲线下面积。
我们研究了9例（43%）胎盘植入患者和12例（57%）胎盘正常的患者。两组间所有三个组织相对增强参数均有显著差异（p < 0.01）。
对胎盘植入高危孕妇在妊娠30 - 35周时使用动态对比增强MRI，可提取胎盘植入与正常胎盘之间有显著差异的组织增强参数。因此，它提供了用于诊断和患者管理的客观参数。
