在临床 3T 扫描仪上使用大视野体部线圈进行 fMRI 的可行性和优化。

Feasibility and optimization ofF MRI on a clinical 3T with a large field-of-view torso coil.

机构信息

Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America.

Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America.

出版信息

Phys Med Biol. 2024 Jun 4;69(12):125002. doi: 10.1088/1361-6560/ad4d50.

Abstract

The objective of this work is to: (1) demonstrate fluorine-19 (F) MRI on a 3T clinical system with a large field of view (FOV) multi-channel torso coil (2) demonstrate an example parameter selection optimization for aF agent to maximize the signal-to-noise ratio (SNR)-efficiency for spoiled gradient echo (SPGR), balanced steady-state free precession (bSSFP), and phase-cycled bSSFP (bSSFP-C), and (3) validate detection feasibility intissues.Measurements were conducted on a 3.0T Discovery MR750w MRI (GE Healthcare, USA) with an 8-channelH/F torso coil (MRI Tools, Germany). Numerical simulations were conducted for perfluoropolyether to determine the theoretical parameters to maximize SNR-efficiency for the sequences. Theoretical parameters were experimentally verified, and the sensitivity of the sequences was compared with a 10 min acquisition time with a 3.125 × 3.125 × 3 mmin-plane resolution. Feasibility of a bSSFP-C was also demonstrated in phantom andtissues.. Flip angles (FAs) of 12 and 64° maximized the signal for SPGR and bSSFP, and validation of optimal FA and receiver bandwidth showed close agreement with numerical simulations. Sensitivities of 2.47, 5.81, and 4.44ms-0.5mM-1 and empirical detection limits of 20.3, 1.5, and 6.2 mM were achieved for SPGR, bSSFP, and bSSFP-C, respectively. bSSFP and bSSFP-C achieved 1.8-fold greater sensitivity over SPGR (< 0.01).bSSFP-C was able to improve sensitivity relative to simple SPGR and reduce both bSSFP banding effects and imaging time. The sequence was used to demonstrate the feasibility ofF MRI at clinical FOVs and field strengths withintissues.

摘要

本研究的目的在于

(1)在具有大视野(FOV)多通道体部线圈的 3T 临床系统上进行氟-19(F)MRI;(2)为 F 造影剂选择优化参数,以最大化扰相梯度回波(SPGR)、平衡稳态自由进动(bSSFP)和相位循环 bSSFP(bSSFP-C)的信噪比(SNR)效率;(3)验证在组织中检测的可行性。在 3.0T Discovery MR750w MRI(美国通用电气医疗系统公司)和 8 通道 H/F 体部线圈(德国 MRI Tools)上进行了测量。针对全氟聚醚进行了数值模拟,以确定最大化序列 SNR 效率的理论参数。实验验证了理论参数,并比较了具有 3.125×3.125×3mm 平面分辨率的 10 分钟采集时间的序列灵敏度。还在体模和组织中证明了 bSSFP-C 的可行性。SPGR 和 bSSFP 的最大信号 FAs 为 12 和 64°,最佳 FA 和接收器带宽的验证与数值模拟结果非常吻合。SPGR、bSSFP 和 bSSFP-C 的灵敏度分别为 2.47、5.81 和 4.44ms-0.5mM-1和经验检测限分别为 20.3、1.5 和 6.2 mM。bSSFP 和 bSSFP-C 的灵敏度分别比 SPGR 高 1.8 倍(<0.01)。bSSFP-C 能够提高灵敏度,减少 bSSFP 带效应并缩短成像时间。该序列用于证明在临床 FOV 和场强下在组织中进行 F MRI 的可行性。

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