Motion robust 4D-MRI sorting based on anatomic feature matching: A digital phantom simulation study.
Motion robust 4D-MRI sorting based on anatomic feature matching: A digital phantom simulation study.
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DOI：
10.1016/j.radmp.2020.01.003
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发表时间：
2020-03
影响因子：
--
通讯作者：
Cai, Jing
中科院分区：
文献类型：
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作者：
Yang, Zi;Ren, Lei;Yin, Fang-Fang;Liang, Xiao;Cai, Jing
由呼吸变化引起的运动伪影在 4D-MRI 图像中很常见。本研究旨在通过开发一种基于解剖特征匹配且适用于电影和顺序采集的新颖、稳健的 4D-MRI 分类方法来减少运动伪影。所提出的方法使用膈肌作为解剖特征来指导4D-MRI图像的排序。最初，获取腹部二维矢状电影 MRI 图像和轴向 MRI 图像。矢状电影 MRI 图像被分为 10 个阶段作为基本事实。接下来，通过将交叉平面中的隔膜位置与地面真实电影 MRI 相匹配来确定每个轴向 MRI 图像的相位。然后，这些匹配的相位轴向图像被分类到与地面真实电影图像相同的 10 相位箱中。最后，根据这些排序的轴向图像重建 10 相 4D-MRI。通过使用 4D 扩展心脏躯干 (XCAT) 数字体模与地面实况进行比较，评估重建的 4D-MRI 数据的准确性。通过计算 4D 体积的总相对误差 (TRE)、估计肿瘤体积的体积百分比差异 (VPD) 和质心偏移 (COMS) 与地面实况 XCAT 图像相比，研究了呼吸信号（包括轴向电影和顺序扫描模式下的规则（余弦函数）和不规则（患者数据））对重建精度的影响。在两种扫描模式下，重建的 4D-MRI 图像与地面真实情况完美匹配，运动伪影最小。两种扫描模式下 EOE 相的 4D 体积、VPD 和 COMS 的平均 TRE 对于规则呼吸为 0.32%/1.20%/±0.05 mm，对于患者不规则呼吸为 1.13%/4.26%/±0.21 mm。初步评估结果说明了基于解剖特征匹配的鲁棒4D-MRI分选方法的可行性。该方法提供了改进的图像质量，同时减少了电影和顺序扫描模式的运动伪影。
Motion artifacts induced by breathing variations are common in 4D-MRI images. This study aims to reduce the motion artifacts by developing a novel, robust 4D-MRI sorting method based on anatomic feature matching and applicable in both cine and sequential acquisition. The proposed method uses the diaphragm as the anatomic feature to guide the sorting of 4D-MRI images. Initially, both abdominal 2D sagittal cine MRI images and axial MRI images were acquired. The sagittal cine MRI images were divided into 10 phases as ground truth. Next, the phase of each axial MRI image is determined by matching its diaphragm position in the intersection plane to the ground truth cine MRI. Then, those matched phases axial images were sorted into 10-phase bins which were identical to the ground truth cine images. Finally, 10-phase 4D-MRI were reconstructed from these sorted axial images. The accuracy of reconstructed 4D-MRI data was evaluated by comparing with the ground truth using the 4D extended Cardiac Torso (XCAT) digital phantom. The effects of breathing signal, including both regular (cosine function) and irregular (patient data) in both axial cine and sequential scanning modes, on reconstruction accuracy were investigated by calculating total relative error (TRE) of the 4D volumes, Volume-Percent-Difference (VPD) and Center-of-Mass-Shift (COMS) of the estimated tumor volume, compared with the ground truth XCAT images. In both scanning modes, reconstructed 4D-MRI images matched well with ground truth with minimal motion artifacts. The averaged TRE of the 4D volume, VPD and COMS of the EOE phase in both scanning modes are 0.32%/1.20%/±0.05 mm for regular breathing, and 1.13%/4.26%/±0.21 mm for patient irregular breathing. The preliminary evaluation results illustrated the feasibility of the robust 4D-MRI sorting method based on anatomic feature matching. This method provides improved image quality with reduced motion artifacts for both cine and sequential scanning modes.