Rapid dual-echo ramped hybrid encoding MR-based attenuation correction (dRHE-MRAC) for PET/MR.
Rapid dual-echo ramped hybrid encoding MR-based attenuation correction (dRHE-MRAC) for PET/MR.
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DOI：
10.1002/mrm.26953
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发表时间：
2018-06
影响因子：
3.3
通讯作者：
McMillan AB
中科院分区：
文献类型：
--
作者：
Jang H;Liu F;Bradshaw T;McMillan AB
在这项研究中，我们提出了一种用于PET/MR成像中基于MR的衰减校正（MRAC）的快速采集方法，其中超短回波时间（UTE）图像和异相回波图像在单次快速扫描（35秒）内以高空间分辨率（1 mm 3）获得，这允许利用4类组织分类准确估计伪CT图像（离散的骨、离散的空气和连续的脂肪和水）。在双回波斜坡混合编码（dRHE）中，UTE回波之后直接跟随第二异相回波，其中利用组合单点成像和3D径向频率编码的混合空间编码来提高两个图像的质量。两点狄克逊重建用于估计脂肪和水分离的图像，并且UTE图像用于估计骨。空气和骨骼分割是通过利用多个UTE图像与先进的混合编码方案，允许重建多个UTE图像。为了评价所提出的方法，dRHE-MRAC，在10名受试者中进行PET/MR脑成像。将与基于CT的衰减校正相关的Dice系数和PET重建误差与现有系统MRAC方法进行比较。在dRHE-MRAC中，软组织、空气和骨的Dice系数分别为0.95±0.01、0.62±0.06和0.78±0.05，与现有方法相比，这是一个显著改善的结果。在大多数脑区，dRHE-MRAC显示PET误差显著降低（小于1%），p值小于0.05。dRHE能够通过非常快速的采集实现MRAC的快速和稳健的成像。
In this study, we propose a rapid acquisition for MR-based attenuation correction (MRAC) in PET/MR imaging, where an ultrashort echo time (UTE) image and an out-of-phase echo image are obtained within a single rapid scan (35sec) at high spatial resolution (1mm3), which allows accurate estimation of a pseudo CT image utilizing 4 class tissue classification (discrete bone, discrete air, and continuous fat and water). In dual echo ramped hybrid encoding (dRHE), a UTE echo is directly followed by a second, out-of-phase echo where hybrid spatial encoding combining single-point imaging and 3D radial frequency encoding is utilized to improve the quality of both images. Two-point Dixon reconstruction is used to estimate fat and water separated images, and UTE images are used to estimate bone. Air and bone segmentation is improved by utilizing multiple UTE images with an advanced hybrid encoding scheme that allows reconstruction of multiple UTE images. To evaluate the proposed method, dRHE-MRAC, PET/MR brain imaging was performed in 10 subjects. Dice coefficients and PET reconstruction errors relative to CT-based attenuation correction were compared to existing system MRAC approaches. In dRHE-MRAC, the Dice coefficients for soft tissue, air, and bone were respectively 0.95±0.01, 0.62±0.06, and 0.78±0.05, which was a significantly improved result compared to existing approaches. In most brain regions, dRHE-MRAC showed significantly reduced PET error (less than 1%) with p-values less than 0.05. dRHE enables rapid and robust imaging for MRAC with a very rapid acquisition.
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影响因子：
3.3
作者：
Feng, Li;Grimm, Robert;Block, Kai Tobias;Chandarana, Hersh;Kim, Sungheon;Xu, Jian;Axel, Leon;Sodickson, Daniel K.;Otazo, Ricardo
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9.3
作者：
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通讯作者：
Schoelkopf, Bernhard
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9.3
作者：
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通讯作者：
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