Image Sciences Institute, 3584 CX Utrecht, The Netherlands.
IEEE Trans Med Imaging. 2009 Oct;28(10):1585-94. doi: 10.1109/TMI.2009.2022368.
Noise filtering techniques that maintain image contrast while decreasing image noise have the potential to optimize the quality of computed tomography (CT) images acquired at reduced radiation dose. In this paper, a hybrid diffusion filter with continuous switch (HDCS) is introduced, which exploits the benefits of three-dimensional edge-enhancing diffusion (EED) and coherence-enhancing diffusion (CED). Noise is filtered, while edges, tubular structures, and small spherical structures are preserved. From ten high dose thorax CT scans, acquired at clinical doses, ultra low dose ( 15 mAs ) scans were simulated and used to evaluate and compare HDCS to other diffusion filters, such as regularized Perona-Malik diffusion and EED. Quantitative results show that the HDCS filter outperforms the other filters in restoring the high dose CT scan from the corresponding simulated low dose scan. A qualitative evaluation was performed on filtered real low dose CT thorax scans. An expert observer scored artifacts as well as fine structures and was asked to choose one of three scans (two filtered (blinded), one unfiltered) for three different settings (trachea, lung, and mediastinal). Overall, the HDCS filtered scan was chosen most often.
在降低辐射剂量的同时保持图像对比度、降低图像噪声的噪声过滤技术有可能优化计算机断层扫描（CT）图像的质量。本文提出了一种具有连续开关的混合扩散滤波器（HDCS），它利用了三维边缘增强扩散（EED）和相干增强扩散（CED）的优势。既能过滤噪声，又能保留边缘、管状结构和小的球形结构。从临床剂量采集的十次高剂量胸部 CT 扫描中，模拟了超低剂量（15 mAs）扫描，并将 HDCS 与其他扩散滤波器（如正则化 Perona-Malik 扩散和 EED）进行评估和比较。定量结果表明，HDCS 滤波器在从相应的模拟低剂量扫描中恢复高剂量 CT 扫描方面优于其他滤波器。对过滤后的真实低剂量 CT 胸部扫描进行了定性评估。一位专家观察者对伪影和精细结构进行评分，并要求他在三种不同的设置（气管、肺和纵隔）下从三个扫描中（两个过滤的（盲），一个未过滤的）选择一个。总的来说，HDCS 过滤后的扫描是最常被选择的。
