Kageyama Sakiko, Sato Tomomi, Iwama Noriyuki, Hamada Hirotaka, Saito Masatoshi, Takase Kei
Department of Diagnostic Radiology, Tohoku University Hospital, Sendai Miyagi, Japan.
Department of Radiology, Tohoku Medical and Pharmaceutical University, Sendai Miyagi, Japan.
Magn Reson Med Sci. 2025 Aug 6;24(3):366-386. doi: 10.2463/mrms.rev.2025-0036. Epub 2025 Jul 31.
The umbilical cord and placenta, classified as fetal appendages, play a crucial role in fetal growth and survival. While ultrasonography remains the primary modality for evaluation, MRI provides a more objective and comprehensive assessment, particularly for the placenta and fetus. Although MRI assessment of the umbilical cord is still emerging and not yet widely adopted by radiologists, MRI has the potential to support and complement ultrasound findings, thereby contributing to safer perinatal management. This review summarizes key MRI findings related to the umbilical cord and associated placental abnormalities. In cases where MRI reports are currently unavailable, ultrasound findings are included to supplement the discussion and to support inferences of potential MRI findings, encouraging future diagnostic applications. Initially, we describe the normal morphology and physiological changes of the umbilical cord and placenta, recommended MRI sequences, and normal imaging findings. Placental abnormalities associated with umbilical cord anomalies, including morphological and positional abnormalities, are reviewed. Variations in umbilical cord insertion, particularly marginal and velamentous insertion, as well as vasa previa, are also discussed. Abnormalities related to umbilical cord position and morphology, such as hypercoiling and hypocoiling, cord knots, nuchal cords, and cord presentation, are examined. Additionally, vascular abnormalities, including single umbilical artery, fused umbilical artery, supernumerary vessels, varices, and aneurysms, are explored along with their underlying mechanisms. Finally, umbilical cord cysts and umbilical cord ulcers are addressed. Advancements in imaging technology, particularly Doppler ultrasonography, have significantly improved the detection and management of umbilical cord and placental abnormalities. Understanding these abnormalities in prenatal MRI evaluation is crucial for improving diagnostic accuracy and optimizing perinatal care. MRI may prove to be a useful adjunct when ultrasound findings are inconclusive or when additional anatomical and functional information is needed. However, further studies are needed to clarify MRI's clinical utility.
脐带和胎盘被归类为胎儿附属物，在胎儿生长和存活中起着至关重要的作用。虽然超声检查仍然是评估的主要方式，但MRI提供了更客观、全面的评估，特别是对于胎盘和胎儿。尽管MRI对脐带的评估仍在发展中，尚未被放射科医生广泛采用，但MRI有潜力支持和补充超声检查结果，从而有助于更安全的围产期管理。本综述总结了与脐带相关的关键MRI表现及相关胎盘异常。在目前尚无MRI报告的情况下，纳入超声检查结果以补充讨论并支持对潜在MRI表现的推断，鼓励未来的诊断应用。首先，我们描述脐带和胎盘的正常形态及生理变化、推荐的MRI序列以及正常的影像学表现。回顾与脐带异常相关的胎盘异常，包括形态和位置异常。还讨论了脐带插入的变异，特别是边缘性和帆状插入以及前置血管。检查与脐带位置和形态相关的异常，如过度卷曲和卷曲不足、脐带打结、绕颈和脐带先露。此外，探讨血管异常，包括单脐动脉、融合脐动脉、额外血管、静脉曲张和动脉瘤及其潜在机制。最后，讨论脐带囊肿和脐带溃疡。成像技术的进步，特别是多普勒超声检查，显著改善了脐带和胎盘异常的检测和管理。了解产前MRI评估中的这些异常对于提高诊断准确性和优化围产期护理至关重要。当超声检查结果不明确或需要额外的解剖和功能信息时，MRI可能被证明是一种有用的辅助手段。然而，需要进一步研究以阐明MRI的临床实用性。
