Bögel Marco, Hofmann Hannes G, Hornegger Joachim, Fahrig Rebecca, Britzen Stefan, Maier Andreas
Pattern Recognition Lab, Friedrich-Alexander-University Erlangen-Nuremberg, 91058 Erlangen, Germany.
Int J Biomed Imaging. 2013;2013:520540. doi: 10.1155/2013/520540. Epub 2013 Jun 6.
Long acquisition times lead to image artifacts in thoracic C-arm CT. Motion blur caused by respiratory motion leads to decreased image quality in many clinical applications. We introduce an image-based method to estimate and compensate respiratory motion in C-arm CT based on diaphragm motion. In order to estimate respiratory motion, we track the contour of the diaphragm in the projection image sequence. Using a motion corrected triangulation approach on the diaphragm vertex, we are able to estimate a motion signal. The estimated motion signal is used to compensate for respiratory motion in the target region, for example, heart or lungs. First, we evaluated our approach in a simulation study using XCAT. As ground truth data was available, a quantitative evaluation was performed. We observed an improvement of about 14% using the structural similarity index. In a real phantom study, using the artiCHEST phantom, we investigated the visibility of bronchial tubes in a porcine lung. Compared to an uncompensated scan, the visibility of bronchial structures is improved drastically. Preliminary results indicate that this kind of motion compensation can deliver a first step in reconstruction image quality improvement. Compared to ground truth data, image quality is still considerably reduced.
长时间采集会导致胸部C形臂CT出现图像伪影。在许多临床应用中，呼吸运动引起的运动模糊会导致图像质量下降。我们介绍一种基于图像的方法，用于基于膈肌运动来估计和补偿C形臂CT中的呼吸运动。为了估计呼吸运动，我们在投影图像序列中跟踪膈肌轮廓。通过对膈肌顶点使用运动校正三角测量法，我们能够估计出一个运动信号。估计出的运动信号用于补偿目标区域（如心脏或肺部）的呼吸运动。首先，我们在使用XCAT的模拟研究中评估了我们的方法。由于有真实数据可用，因此进行了定量评估。使用结构相似性指数，我们观察到约14%的改善。在实际体模研究中，使用artiCHEST体模，我们研究了猪肺中支气管的可视性。与未补偿扫描相比，支气管结构的可视性得到了极大改善。初步结果表明，这种运动补偿可以在重建图像质量改善方面迈出第一步。与真实数据相比，图像质量仍然大幅降低。
