Dual-pathway multi-echo sequence for simultaneous frequency and T2 mapping.
Dual-pathway multi-echo sequence for simultaneous frequency and T2 mapping.
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DOI：
10.1016/j.jmr.2016.01.019
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发表时间：
2016-04
期刊：
影响因子：
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通讯作者：
Madore B
中科院分区：
文献类型：
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作者：
Cheng CC;Mei CS;Duryea J;Chung HW;Chao TC;Panych LP;Madore B
提出了一种双通道多回波稳态序列和重建算法，以获取T2、T2*和场图信息。通常，T2映射需要基于自旋回波的脉冲序列，而场映射需要梯度回波，这使得联合获取这两种类型的信息变得困难。这里使用双路径多回波脉冲序列来从相同的采集数据生成T2和场图。例如，该方法可用于在热疗期间获得体温和组织损伤信息，或从同一头部扫描获得敏感度和T2信息，或在膝盖扫描期间生成额外的T2图。在凝胶模型、体外牛肌肉和12名志愿者中生成了定量的T2、T2*和场图。T2结果对照自旋回波参考标准进行了验证：基于模体中感兴趣区域分析的线性回归提供了非常一致的结果(斜率/R2=0.99/0.998)。在活体内对R2=1/T2进行的Bland-Altman像素分析显示，四名志愿者的平均偏差为0.034赫兹(约0.3%)。体外结果表明，无论有无运动，基于T2的组织损伤检测比基于温度-剂量测量的组织损伤检测可能被证明对运动更稳健。在测温、磁化率加权成像和膝关节成像环境中，从相同的数据集同时获得T2、T2*和场图。
To present a dual-pathway multi-echo steady state sequence and reconstruction algorithm to capture T2, T2* and field map information. Typically, pulse sequences based on spin echoes are needed for T2 mapping while gradient echoes are needed for field mapping, making it difficult to jointly acquire both types of information. A dual-pathway multi-echo pulse sequence is employed here to generate T2 and field maps from the same acquired data. The approach might be used, for example, to obtain both thermometry and tissue damage information during thermal therapies, or susceptibility and T2 information from a same head scan, or to generate bonus T2 maps during a knee scan. Quantitative T2, T2* and field maps were generated in gel phantoms, ex vivo bovine muscle, and twelve volunteers. T2 results were validated against a spin-echo reference standard: A linear regression based on ROI analysis in phantoms provided close agreement (slope/R2 = 0.99/0.998). A pixel-wise in vivo Bland-Altman analysis of R2=1/T2 showed a bias of 0.034 Hz (about 0.3%), as averaged over four volunteers. Ex vivo results, with and without motion, suggested that tissue damage detection based on T2 rather than temperature-dose measurements might prove more robust to motion. T2, T2* and field maps were obtained simultaneously, from the same datasets, in thermometry, susceptibility-weighted imaging and knee-imaging contexts.