Artifacts at Cardiac CT: Physics and Solutions
Artifacts at Cardiac CT: Physics and Solutions
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DOI：
10.1148/rg.2016160079
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发表时间：
2016-11-01
期刊：
影响因子：
5.5
通讯作者：
Rajiah, Prabhakar
中科院分区：
文献类型：
--
作者：
Kalisz, Kevin;Buethe, Ji;Rajiah, Prabhakar
计算机断层扫描容易受到各种各样的伪影的影响，包括患者和技术特定的伪影，其中一些是心脏成像所特有的。运动是伪影最常见的来源，可由患者、心脏或呼吸运动引起。通过降低心率和变异性以及数据采集的持续时间，可以减少心脏运动伪影；在心脏周期内调整数据窗口的位置；执行单次心跳扫描；使用多段重建、运动校正算法和心电图编辑。呼吸运动伪影可以通过适当的屏气和缩短扫描时间最小化。部分体积平均是由体素内包含的所有组织的衰减值平均引起的，可以通过提高空间分辨率、使用更高的x射线能量或用更宽的窗口宽度显示图像来减少。射线硬化伪影是由x射线的多能性引起的，可以通过x射线过滤、应用高能x射线、改变患者体位、修改造影剂方案和应用某些重建算法来减少。金属伪影很复杂，有多种原因，包括x射线散射、穿透不足、运动和衰减值，这些值超出了霍斯菲尔德单元的典型动态范围。量子斑点或噪声是由组织穿透不足引起的，可以通过增加管电流或峰值管电位、重建较厚的切片、增加旋转时间、使用适当的患者定位和应用迭代重建算法来改善。(c) rsna, 2016
Computed tomography is vulnerable to a wide variety of artifacts, including patient-and technique-specific artifacts, some of which are unique to imaging of the heart. Motion is the most common source of artifacts and can be caused by patient, cardiac, or respiratory motion. Cardiac motion artifacts can be reduced by decreasing the heart rate and variability and the duration of data acquisition; adjusting the placement of the data window within a cardiac cycle; performing single-heartbeat scanning; and using multisegment reconstruction, motion-correction algorithms, and electrocardiographic editing. Respiratory motion artifacts can be minimized with proper breath holding and shortened scan duration. Partial volume averaging is caused by the averaging of attenuation values from all tissue contained within a voxel and can be reduced by improving the spatial resolution, using a higher x-ray energy, or displaying images with a wider window width. Beam-hardening artifacts are caused by the polyenergetic nature of the x-ray beam and can be reduced by using x-ray filtration, applying higher-energy x-rays, altering patient position, modifying contrast material protocols, and applying certain reconstruction algorithms. Metal artifacts are complex and have multiple causes, including x-ray scatter, underpenetration, motion, and attenuation values that exceed the typical dynamic range of Hounsfield units. Quantum mottle or noise is caused by insufficient penetration of tissue and can be improved by increasing the tube current or peak tube potential, reconstructing thicker sections, increasing the rotation time, using appropriate patient positioning, and applying iterative reconstruction algorithms. (C) RSNA, 2016