在CEST MR中侧带 - 如何识别和避免它们
Jan-Rüdiger Schüre1, Simon Weinmüller1, Lukas Kamm1
1Institute of Neuroradiology, University Clinic Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
Magnetic resonance in medicine
|February 6, 2024
概括
脉冲化学交换和转移 (CEST) 序列可能会由于相位积累而导致工件. 在和列车期间的梯度破坏至关重要,以防止误解这些侧带作为实际的CEST效应,特别是在液态环境中.
科学领域:
- 磁共振成像是一种磁共振成像技术.
- 生物医学工程 生物医学工程
- 频谱学是一种光谱学.
背景情况:
- 脉冲化学交换和转移 (CEST) 序列对于临床MRI来管理放大器功率和特定吸收率 (SAR) 是必不可少的.
- 磁化可以在非共振射频 (RF) 辐射和脉冲延迟中在脉冲CEST序列中积累相对相位.
- 这些累积的相可以导致人工物,如果不适当地管理,特别是没有间脉冲梯度破坏.
研究的目的:
- 调查脉冲CEST序列中侧带工件的性质和影响.
- 为了证明在脉冲CEST采集过程中考虑磁化相积的重要性.
- 要突出梯度破坏在脉冲CEST中减轻文物中的作用.
主要方法:
- 在3特斯拉利用CEST-3D快照梯度回声序进行文物调查.
- 使用Pulseq-CEST进行了Bloch-McConnell模拟.
- 进行了体外和体内实验,以验证模拟结果.
主要成果:
- 在Z光谱中识别了侧带,通常需要高采样才能清晰可视化.
- 观察到B0不均性和RF相循环影响侧带结构.
- 在体内发现侧带主要存在于像脑脊液 (CSF) 这样的液体区.
- 证明了间脉冲梯度破坏有效地抑制了多脉冲侧带.
结论:
- 脉冲CEST实验容易受到侧带工件的影响,受到梯度和射频破坏的影响,类似于成像序列.
- 梯度破坏对于防止误解侧带作为真正的CEST效应至关重要,特别是在液态环境,病态组织或水附近的共振中.
- 建议提前模拟脉冲CEST序列,以避免潜在的工件并确保准确的结果.
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