Kägebein Urte, Speck Oliver, Wacker Frank, Hensen Bennet
Biomedical Magnetic Resonance, Otto-von-Guericke University.
STIMULATE - Solution Centre for Image Guided Local Therapies, Otto-von-Guericke University Magdeburg, Magdeburg.
Top Magn Reson Imaging. 2018 Feb;27(1):53-61. doi: 10.1097/RMR.0000000000000157.
The unique ability of magnetic resonance imaging to measure temperature noninvasively, in vivo, makes it an attractive tool for monitoring interventional procedures, such as radiofrequency or microwave ablation in real-time. The most frequently used approach for magnetic resonance-based temperature measurement is proton resonance frequency (PRF) thermometry. Although it has many advantages, including tissue-independence and real-time capability, the main drawback is its motion sensitivity. This is likely the reason PRF thermometry in moving organs, such as the liver, is not commonly used in the clinical arena. In recent years, however, several developments suggest that motion-corrected thermometry in the liver is achievable. The present article summarizes the diverse attempts to correct thermometry in the liver. Therefore, the physical principle of PRF is introduced, with additional references for necrosis zone estimation and how to deal with fat phase modulation, and main magnetic field drifts. The primary categories of motion correction are presented, including general methods for motion compensation and library-based approaches, and referenceless thermometry and hybrid methods. Practical validation of the described methods in larger patient groups will be necessary to establish accurate motion-corrected thermometry in the clinical arena, with the goal of complete liver tumor ablation.
磁共振成像能够在体内进行非侵入式温度测量，这一独特能力使其成为实时监测介入手术（如射频或微波消融）的理想工具。基于磁共振的温度测量最常用的方法是质子共振频率（PRF）测温法。尽管它有许多优点，包括与组织无关和实时性，但主要缺点是对运动敏感。这可能就是PRF测温法在肝脏等运动器官中在临床领域不常用的原因。然而，近年来的一些进展表明，肝脏中的运动校正测温是可以实现的。本文总结了在肝脏中校正测温的各种尝试。因此，介绍了PRF的物理原理，并提供了坏死区估计以及如何处理脂肪相位调制和主磁场漂移的相关参考文献。介绍了运动校正的主要类别，包括运动补偿的一般方法和基于库的方法、无参考测温法和混合方法。为了在临床领域建立准确的运动校正测温法以实现完全肝肿瘤消融，有必要在更大的患者群体中对所述方法进行实际验证。
