Department of Early Life Imaging, King's College London, London, UK.
Department of Women's and Children's Health, King's College London, London, UK.
Sci Rep. 2024 Nov 19;14(1):28594. doi: 10.1038/s41598-024-77406-6.
Placental MRI is increasingly implemented in clinical obstetrics and research. Functional imaging, especially T2*, has been shown to vary across gestation and in pathology. Translation into the clinical arena has been slow because of time taken to mask the region of interest and owing to differences in T2* results depending on field strength. This paper contributes methodology to remove these barriers by utilising data from 0.55, 1.5 and 3T MRI to provide a fully automated segmentation tool; determining field strength dependency of placental assessment techniques; and deriving normal ranges for T2* by gestational age but independent of field strength. T2* datasets were acquired across field strengths. Automatic quantification including fully automatic masking was achieved and tested in 270 datasets across fields. Normal curves for quantitative placental mean T2*, volume and other derived measurements were obtained in 273 fetal MRI scans and z-scores calculated. The fully automatic segmentation achieved excellent quantification results (Dice scores of 0.807 at 3T, 0.796 at 1.5T and 0.815 at 0.55T.). Similar changes were seen between placental T2* and gestational age across all three field strengths (p < 0.05). Z-scores were generated. This study provides confidence in the translatability of T2* trends across field strengths in fetal imaging.
胎盘 MRI 在临床产科和研究中应用日益广泛。功能成像，尤其是 T2*，已被证明在妊娠期间和病理学中存在差异。由于需要时间来屏蔽感兴趣区域，并且由于 T2结果因场强而异，因此其在临床领域的转化进展缓慢。本文通过利用 0.55、1.5 和 3T MRI 数据提供完全自动化的分割工具，来消除这些障碍，确定胎盘评估技术的场强依赖性，并根据胎龄导出 T2的正常范围，而与场强无关。在不同场强下采集 T2数据集。在跨越场强的 270 个数据集上实现了自动定量，包括全自动掩蔽，并进行了测试。在 273 例胎儿 MRI 扫描中获得了定量胎盘平均 T2、体积和其他衍生测量的正常曲线，并计算了 z 分数。全自动分割实现了出色的定量结果（在 3T 时的骰子分数为 0.807，在 1.5T 时为 0.796，在 0.55T 时为 0.815）。在所有三种场强下，胎盘 T2和胎龄之间都观察到类似的变化（p<0.05）。生成了 z 分数。本研究为 T2趋势在胎儿成像中场强间的可转化性提供了信心。
