模拟平面内磁场梯度对不对称的自旋回声图像的影响,用回声平面成像读出结果
Philipp Wallimann1,2, Patrick L Y Tang2,3,4, Fatemeh Arzanforoosh2,4,5
1Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland.
Magnetic resonance in medicine
|July 17, 2025
概括
在相编码方向上的宏观磁场梯度 (MFGs) 显著影响不对称旋转回声 (ASE) 和回声平面成像 (EPI) 数据. 纠正或减轻这些MFG对于精确的定量血氧水平依赖 (qBOLD) 测量至关重要.
科学领域:
- 磁共振成像 (MRI) 是一种磁共振成像技术.
- 生物医学工程 生物医学工程
- 神经成像是一种神经成像.
背景情况:
- 非对称旋转回声 (ASE) 序列与回声平面成像 (EPI) 读数对磁场变化敏感.
- 在相编码方向上的宏观磁场梯度 (MFGs) 可以在EPI数据中引入文物.
- 定量血氧水平依赖 (qBOLD) 成像依赖于准确的信号测量,这可能会受到MFGs的影响.
研究的目的:
- 调查阶段编码方向MFG对ASE-EPIMR图像的影响.
- 评估这些MFG对定量血氧水平依赖 (qBOLD) 参数的影响.
- 提出一种方法来缓解MFG诱导的文物.
主要方法:
- 扩展了ASE信号方程,以结合由于MFG而发生的局部变化的时间偏移 ().
- 使用模拟评估对qBOLD参数的影响.
- 在健康的志愿者中获得了地图和ASE图像,具有不同的阶段编码方向和并行成像因子.
- 进行线性回归来验证与MFG测量的信号方程.
主要成果:
- 模拟显示,qBOLD参数在本地.的实质性修改.
- 志愿者数据显示了依赖于MFG和时间偏移的对数信号强度比 ().
- 观察到的效应在较高的并行成像因子下显著减少.
结论:
- 拟议的信号模型准确地描述了相位编码方向MFG对ASE-EPI图像的影响.
- 这些MFG效应与qBOLD测量相关.
- 缓解策略,例如使用高并行成像因子,对于准确的qBOLD分析是必要的.
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