Motion artefacts in cone beam CT: an in vitro study about the effects on the images
Motion artefacts in cone beam CT: an in vitro study about the effects on the images
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DOI：
10.1259/bjr.20150687
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发表时间：
2016-01-01
影响因子：
2.6
通讯作者：
Colagrande, Stefano
中科院分区：
文献类型：
--
作者：
Nardi, Cosimo;Molteni, Roberto;Colagrande, Stefano
目的：在锥形束 CT (CBCT) 中，由不自主运动引起的患者固定不完美是造成伪影和图像质量下降的最重要原因之一。文献中的各种作品都讨论了这个主题，但很少以系统的方式将运动的性质与伪影类型和图像退化相关联，并对相关性进行分析和解释。 方法：在扫描过程中可能发生的所有三种类型的运动（点头、倾斜和滚动）均以从突然到渐进的各种方式在整个扫描过程中以不同的时间和角度在大范围的位移上应用于干燥的头骨。进行了 84 次扫描，颅骨运动不同，生成的图像由两名熟练的放射科医生检查，按四分制评分并进行统计分析。使用商用 CBCT 机器，以仰卧位患者定位为特色。结果：不同类型的运动在解剖结构的不同部位会产生不同的伪影。一般来说，短时间的移动可能会导致双轮廓（双边或单边，具体取决于它们发生的扫描角度），而逐渐的移动会导致模糊。结论：并非所有移动都会导致同样危害图像的运动伪影。滚动是对图像诊断价值影响最严重的运动类型。知识进步：这些发现可以帮助从业者识别运动伪影的原因以及由此导致的图像质量下降，并进行补救，并帮助制造商改进患者定位设备。
Objective: In cone beam CT (CBCT), imperfect patient immobility, caused by involuntary movements, is one of the most important causes of artefacts and image quality degradation. Various works in literature address this topic, but seldom is the nature of the movement correlated with the type of artefact and the image degradation in a systematic manner, and the correlation analyzed and explained.Methods: All three types of movements that can occur during a scan-nodding, tilting and rolling-were applied to a dry skull, in various manners from abrupt to gradual through the entire scan, at different times and angles, over a wide range of displacements. 84 scans were performed, with different skull movements, and the resulting images examined by two skilled radiologists, rated in a four-point scale and statistically analyzed. A commercial CBCT machine was used, featuring supine patient positioning.Results: Different types of movements induce different artefacts, in different parts of the anatomy. In general, movement of short duration may lead to double contours (bilateral or monolateral depending upon the angle of the scan at which they occur), whereas gradual movements result into blurring.Conclusion: Not all movements cause motion artefacts that equally jeopardize the image. Rolling is the type of movement that most severely affects the image diagnostic value.Advances in knowledge: These findings may help practitioners to identify the causes of motion artefacts and the resulting image degradation, and remediate them, and manufacturers to improve the patient-positioning devices.