Respiration artifact correction in three-dimensional proton resonance frequency MR thermometry using phase navigators.
Respiration artifact correction in three-dimensional proton resonance frequency MR thermometry using phase navigators.
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DOI：
10.1002/mrm.25860
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发表时间：
2016-07
影响因子：
3.3
通讯作者：
Parker DL
中科院分区：
文献类型：
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作者：
Svedin BT;Payne A;Parker DL
在呼吸诱导B 0变化的情况下，开发可靠的3D分段回波平面成像（seg-EPI）质子共振频率（PRF）温度监测。在EPI读出之前和之后，将自由感应衰减（FID）相位导航器插入到3D seg-EPI序列中，以监测B 0场变化。使用场变化估计，调整每个k空间线的相位以从呼吸诱导的非共振中去除附加相位。在模拟呼吸的体模中使用MR引导聚焦超声（MRgFUS）加热时，以及在健康体内乳房的非加热条件下，对该校正技术进行评价。采用k空间相位校正后，5名志愿者乳腺的幅度图像和PRF温度测量值的标准差分别平均提高了1.5和2.1倍。在模型中用MRgFUS加热时，在校正后观察到温度估计的准确性提高。基于放置在回波序列之前和之后的两个FID导航器的相位校正为在存在由于呼吸引起的场变化的情况下实施热疗法治疗的3D监测提供了有希望的结果。
To develop reliable 3D segmented echo-planar imaging (seg-EPI) proton resonance frequency (PRF) temperature monitoring in the presence of respiration induced B0 variation. A free induction decay (FID) phase navigator is inserted into a 3D seg-EPI sequence before and after EPI readout, to monitor B0 field variations. Using the field change estimates, the phase of each k-space line is adjusted to remove the additional phase from the respiratory induced off-resonance. This correction technique is evaluated while heating with MR guided focused ultrasound (MRgFUS) in phantoms with simulated breathing and during non-heating conditions in healthy in vivo breasts. With k-space phase correction, the standard deviation of magnitude images and PRF temperature measurements in breast from 5 volunteers improved by an average factor of 1.5 and 2.1, respectively. Improved accuracy of temperature estimates was observed after correction while heating with MRgFUS in phantoms. Phase correction based on two FID navigators placed before and after the echo-train provides promising results for implementing 3D monitoring of thermal therapy treatments in the presence of field variations due to respiration.