基于几何分析法的单侧磁共振前向建模和 T2 拟合误差评估

IF 4.2 2区 地球科学 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS
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引用次数: 0

摘要

单面磁共振(SSMR)在水探测方面具有便携性和无创测量的优势,在地下水勘探、石油测井和土壤湿度监测方面具有巨大的潜在应用价值。然而,由于 SSMR 固有的高度不均匀静态磁场和射频(RF)场,因此必须使用卡尔-普塞尔-梅博姆-吉尔(CPMG)序列测量方案。为了加速脉冲激励期间的正向建模,我们引入了几何分析方法(GAM),并利用其主要参数评估 T2 误差。GAM 包括对磁化矢量进行空间几何旋转,从而得出布洛赫方程的解析解,并忽略弛豫效应。与旋转矩阵(RM)方法相比,GAM 显示出很高的准确性,并将计算时间减少了约 20.9%。通过分析解析公式中支配磁化矢量的主要参数,我们评估了它们对通过拟合 SE 信号获得的横向弛豫时间 (T2) 的影响。最终,验证了单面哈尔巴赫磁体阵列感兴趣区(ROI)内 CPMG 序列的正向建模结果。T2 拟合误差随着主要参数偏离理想值而增加,突出了它们在 T2 拟合结果中的重要作用。这项研究为优化 SSMR 磁体和射频线圈的设计提供了理论基础。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Forward modeling of single-sided magnetic resonance and evaluation of T2 fitting error based on geometric analytical method

Single-sided magnetic resonance (SSMR) offers advantages of portability and noninvasive measurement for water detection, with significant potential applications in groundwater exploration, petroleum well logging, and soil moisture monitoring. However, the inherent highly inhomogeneous static magnetic field and radiofrequency (RF) field in SSMR necessitate the utilization of the Carr–Purcell–Meiboom–Gill (CPMG) sequence measurement scheme. To accelerate forward modeling during pulse excitation, we introduce a Geometric Analysis Method (GAM) and assess T2 error using its primary parameters. The GAM involves applying spatial geometric rotations on the magnetization vector, leading to an analytical solution to the Bloch equation that disregards relaxation effects. Compared with the rotation matrix (RM) method, the GAM demonstrates high accuracy and reduces computational time by approximately 20.9%. By analyzing the primary parameters governing the magnetization vector in the analytical formula, we evaluated their impact on the transverse relaxation time (T2) obtained through fitting the SE signal. Ultimately, the forward modeling results of the CPMG sequence within the region of interest (ROI) of a single-sided Halbach magnet array are validated. The T2 fitting error increases as the primary parameters deviate from the ideal values, highlighting their significant role in the T2 fitting results. This study provides a theoretical foundation for optimizing the design of SSMR magnets and RF coils.

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来源期刊
Computers & Geosciences
Computers & Geosciences 地学-地球科学综合
CiteScore
9.30
自引率
6.80%
发文量
164
审稿时长
3.4 months
期刊介绍: Computers & Geosciences publishes high impact, original research at the interface between Computer Sciences and Geosciences. Publications should apply modern computer science paradigms, whether computational or informatics-based, to address problems in the geosciences.
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