BACKGROUND MRI and CT have been extensively used to study fetal anatomy for research and diagnostic purposes, enabling minimally invasive autopsy and giving insight in human fetal development. Novel (contrast-enhanced) microfocus CT (micro-CT) and ultra-high-field (≥ 7.0 T) MRI (UHF-MRI) techniques now enable micron-level resolution that combats the disadvantages of low-field MRI and conventional CT. Thereby, they might be suitable to study fetal anatomy in high detail and, in time, contribute to the postmortem diagnosis of fetal conditions. OBJECTIVES (1) To systematically examine the usability of micro-CT and UHF-MRI to study postmortem human fetal anatomy, and (2) to analyze factors that govern success at each step of the specimen preparation and imaging. METHOD MEDLINE and EMBASE were systematically searched to identify publications on fetal imaging by micro-CT or UHF-MRI. Scanning protocols were summarized and best practices concerning specimen preparation and imaging were enumerated. RESULTS Thirty-two publications reporting on micro-CT and UHF-MRI were included. The majority of the publications focused on imaging organs separately and seven publications focused on whole body imaging, demonstrating the possibility of visualization of small anatomical structures with a resolution well below 100 μm. When imaging soft tissues by micro-CT, the fetus should be stained by immersion in Lugol's staining solution. CONCLUSION Micro-CT and UHF-MRI are both excellent imaging techniques to provide detailed images of gross anatomy of human fetuses. The present study offers an overview of the current best practices when using micro-CT and/or UHF-MRI to study fetal anatomy for clinical and research purposes. KEY POINTS • Micro-CT and UHF-MRI can both be used to study postmortem human fetal anatomy for clinical and research purposes. • Micro-CT enables high-resolution imaging of fetal specimens in relatively short scanning time. However, tissue staining using a contrast solution is necessary to enable soft-tissue visualization. • UHF-MRI enables high-resolution imaging of fetal specimens, without the necessity of prior staining, but with the drawback of long scanning time.

中文翻译：

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研究死后人类胎儿解剖学的新型成像技术：对微焦点 CT 和超高场 MRI 的系统评价。

背景技术 MRI 和 CT 已广泛用于研究胎儿解剖结构以用于研究和诊断目的，从而能够进行微创尸检并深入了解人类胎儿发育。新型（对比增强）微焦点 CT (micro-CT) 和超高场 (≥ 7.0 T) MRI (UHF-MRI) 技术现在可实现微米级分辨率，从而克服低场 MRI 和传统 CT 的缺点。因此，它们可能适合详细研究胎儿解剖结构，并及时有助于胎儿状况的死后诊断。目标 (1) 系统地检查显微 CT 和 UHF-MRI 研究死后人类胎儿解剖学的可用性，以及 (2) 分析标本制备和成像每个步骤成功的控制因素。方法 系统地搜索 MEDLINE 和 EMBASE，以确定有关通过显微 CT 或 UHF-MRI 进行胎儿成像的出版物。总结了扫描协议，并列举了有关标本制备和成像的最佳实践。结果 包括 32 篇关于显微 CT 和 UHF-MRI 报告的出版物。大多数出版物分别侧重于成像器官，七篇出版物侧重于全身成像，展示了分辨率远低于 100 μm 的小型解剖结构可视化的可能性。显微 CT 对软组织成像时，应将胎儿浸入卢戈氏染色液中进行染色。结论 Micro-CT 和 UHF-MRI 都是出色的成像技术，可提供人类胎儿大体解剖结构的详细图像。本研究概述了当前使用显微 CT 和/或 UHF-MRI 研究胎儿解剖结构以用于临床和研究目的的最佳实践。要点 • Micro-CT 和 UHF-MRI 均可用于研究死后人类胎儿解剖结构，用于临床和研究目的。• Micro-CT 能够在相对较短的扫描时间内对胎儿标本进行高分辨率成像。然而，必须使用对比溶液进行组织染色才能实现软组织可视化。• UHF-MRI 能够对胎儿标本进行高分辨率成像，无需事先染色，但缺点是扫描时间长。要点 • Micro-CT 和 UHF-MRI 均可用于研究死后人类胎儿解剖结构，用于临床和研究目的。• Micro-CT 能够在相对较短的扫描时间内对胎儿标本进行高分辨率成像。然而，必须使用对比溶液进行组织染色才能实现软组织可视化。• UHF-MRI 能够对胎儿标本进行高分辨率成像，无需事先染色，但缺点是扫描时间长。要点 • Micro-CT 和 UHF-MRI 均可用于研究死后人类胎儿解剖结构，用于临床和研究目的。• Micro-CT 能够在相对较短的扫描时间内对胎儿标本进行高分辨率成像。然而，必须使用对比溶液进行组织染色才能实现软组织可视化。• UHF-MRI 能够对胎儿标本进行高分辨率成像，无需事先染色，但缺点是扫描时间长。