Soullié Paul, Missoffe Alexia, Ambarki Khalid, Felblinger Jacques, Odille Freddy
IADI, INSERM U1254, Université de Lorraine, Nancy, France.
Siemens Healthcare, Erlangen, Germany.
Magn Reson Med. 2021 Feb;85(2):762-776. doi: 10.1002/mrm.28458. Epub 2020 Aug 11.
To develop a fast and easy-to-use electrical properties tomography (EPT) method based on a single MR scan, avoiding both the need of a B -map and transceive phase assumption, and that is robust against noise.
Derived from Maxwell's equations, conductivity, and permittivity are reconstructed from a new partial differential equation involving the product of the RF fields and its derivatives. This also allows us to clarify and revisit the relevance of common assumptions of MREPT.
Our new governing equation is solved using a 3D finite-difference scheme and compared to previous frameworks. The benefits of our method over selected existing MREPT methods are demonstrated for different simulation models, as well as for both an inhomogeneous agar phantom gel and in vivo brain data at 3T.
Simulation and experimental results are illustrated to highlight the merits of the proposed method over existing methods. We show the validity of our algorithm in versatile configurations, with many transition regions notably. Complex admittivity maps are also provided as a complementary MR contrast.
Because it avoids time-consuming RF field mapping and generalizes the use of standard MR image for electrical properties reconstruction, this contribution is promising as a new step forward for clinical applications.
基于单次磁共振扫描开发一种快速且易于使用的电阻抗断层成像（EPT）方法，避免对B图的需求和收发相位假设，并且对噪声具有鲁棒性。
从麦克斯韦方程组推导而来，电导率和介电常数由一个涉及射频场及其导数乘积的新偏微分方程重建。这也使我们能够阐明并重新审视磁共振弹性成像（MREPT）常见假设的相关性。
使用三维有限差分格式求解我们的新控制方程，并与先前的框架进行比较。针对不同的模拟模型，以及非均匀琼脂体模凝胶和3T场强下的活体脑数据，展示了我们的方法相对于选定的现有MREPT方法的优势。
通过模拟和实验结果突出了所提方法相对于现有方法的优点。我们展示了算法在多种配置下的有效性，尤其是在许多过渡区域。还提供了复介电常数图作为一种补充性的磁共振对比度。
由于该方法避免了耗时的射频场映射，并将标准磁共振图像用于电阻抗重建进行了推广，因此有望成为临床应用向前迈出的新一步。
