Global Maxwell Tomography Using the Volume-Surface Integral Equation for Improved Estimation of Electrical Properties.

IF 4.4 2区医学 Q2 ENGINEERING, BIOMEDICAL

IEEE Transactions on Biomedical Engineering Pub Date : 2025-05-26 DOI:10.1109/TBME.2025.3572800

Ilias I Giannakopoulos, Jose E Cruz Serralles, Jan Paska, Martijn A Cloos, Ryan Brown, Riccardo Lattanzi

{"title":"Global Maxwell Tomography Using the Volume-Surface Integral Equation for Improved Estimation of Electrical Properties.","authors":"Ilias I Giannakopoulos, Jose E Cruz Serralles, Jan Paska, Martijn A Cloos, Ryan Brown, Riccardo Lattanzi","doi":"10.1109/TBME.2025.3572800","DOIUrl":null,"url":null,"abstract":"Objective: Global Maxwell Tomography (GMT) is a noninvasive inverse optimization method for the estimation of electrical properties (EP) from magnetic resonance (MR) measurements. GMT uses the volume integral equation (VIE) in the forward problem and assumes that the sample has negligible effect on the coil currents. Consequently, GMT calculates the coil's incident fields with an initial EP distribution and keeps them constant for all optimization iterations. This can lead to erroneous reconstructions. This work introduces a novel version of GMT that replaces VIE with the volume-surface integral equation (VSIE), which recalculates the coil currents at every iteration based on updated EP estimates before computing the associated fields.Methods: We simulated an 8-channel transceiver coil array for 7 T brain imaging and reconstructed the EP of a realistic head model using VSIE-based GMT. We built the coil, collected experimental MR measurements, and reconstructed EP of a two-compartment phantom.Results: In simulations, VSIE-based GMT outperformed VIE-based GMT by at least 12% for both EP. In experiments, the relative difference with respect to probe-measured EP values in the inner (outer) compartment was 13% (26%) and 17% (33%) for the permittivity and conductivity, respectively.Conclusion: The use of VSIE over VIE enhances GMT's performance by accounting for the effect of the EP on the coil currents.Significance: VSIE-based GMT does not rely on an initial EP estimate, rendering it more suitable for experimental reconstructions compared to the VIE-based GMT.","PeriodicalId":13245,"journal":{"name":"IEEE Transactions on Biomedical Engineering","volume":"PP ","pages":""},"PeriodicalIF":4.4000,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Transactions on Biomedical Engineering","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1109/TBME.2025.3572800","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, BIOMEDICAL","Score":null,"Total":0}

引用次数: 0

Abstract

Objective: Global Maxwell Tomography (GMT) is a noninvasive inverse optimization method for the estimation of electrical properties (EP) from magnetic resonance (MR) measurements. GMT uses the volume integral equation (VIE) in the forward problem and assumes that the sample has negligible effect on the coil currents. Consequently, GMT calculates the coil's incident fields with an initial EP distribution and keeps them constant for all optimization iterations. This can lead to erroneous reconstructions. This work introduces a novel version of GMT that replaces VIE with the volume-surface integral equation (VSIE), which recalculates the coil currents at every iteration based on updated EP estimates before computing the associated fields.

Methods: We simulated an 8-channel transceiver coil array for 7 T brain imaging and reconstructed the EP of a realistic head model using VSIE-based GMT. We built the coil, collected experimental MR measurements, and reconstructed EP of a two-compartment phantom.

Results: In simulations, VSIE-based GMT outperformed VIE-based GMT by at least 12% for both EP. In experiments, the relative difference with respect to probe-measured EP values in the inner (outer) compartment was 13% (26%) and 17% (33%) for the permittivity and conductivity, respectively.

Conclusion: The use of VSIE over VIE enhances GMT's performance by accounting for the effect of the EP on the coil currents.

Significance: VSIE-based GMT does not rely on an initial EP estimate, rendering it more suitable for experimental reconstructions compared to the VIE-based GMT.

查看原文本刊更多论文

利用体积-表面积分方程改进电学性质估计的全局Maxwell层析成像。

目的：全局麦克斯韦层析成像（GMT）是一种非侵入性的逆优化方法，用于从磁共振（MR）测量中估计电性质（EP）。GMT在正向问题中使用体积积分方程（VIE），并假设样品对线圈电流的影响可以忽略不计。因此，GMT以初始EP分布计算线圈的入射场，并在所有优化迭代中保持恒定。这可能导致错误的重建。这项工作引入了一种新的GMT版本，它用体积-表面积分方程（VSIE）取代了VIE，它在计算相关场之前，根据更新的EP估计，在每次迭代中重新计算线圈电流。方法：模拟用于7 T脑成像的8通道收发线圈阵列，并使用基于vsie的GMT重建真实头部模型的EP。我们构建了线圈，收集了实验MR测量数据，并重建了双腔体的EP。结果：在模拟中，对于两种EP，基于vsi的GMT比基于vie的GMT至少高出12%。在实验中，介电常数和电导率与探针测量的内（外）室EP值的相对差异分别为13%（26%）和17%（33%）。结论：通过考虑EP对线圈电流的影响，VSIE在VIE上的使用提高了GMT的性能。意义：基于vsi的GMT不依赖于初始EP估计，与基于vsi的GMT相比，它更适合实验重建。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

IEEE Transactions on Biomedical Engineering 工程技术-工程：生物医学

CiteScore

9.40

自引率

4.30%

发文量

880

审稿时长

2.5 months

期刊介绍： IEEE Transactions on Biomedical Engineering contains basic and applied papers dealing with biomedical engineering. Papers range from engineering development in methods and techniques with biomedical applications to experimental and clinical investigations with engineering contributions.