Favorable noise uniformity properties of Fourier-based interpolation and reconstruction approaches in single-slice helical computed tomography.
Favorable noise uniformity properties of Fourier-based interpolation and reconstruction approaches in single-slice helical computed tomography.
复制标题
单层螺旋计算机断层扫描中基于傅立叶的插值和重建方法的良好噪声均匀性特性。
DOI：
10.1118/1.1477229
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发表时间：
2002
期刊：
影响因子：
3.8
通讯作者：
Pan,Xiaochuan
中科院分区：
文献类型：
--
作者：
LaRivière,PatrickJ;Pan,Xiaochuan
用标准方法从单层螺旋计算机断层扫描(CT)数据重建的体积已经被证明具有与传统CT相比高度不均匀的噪声水平。这些噪声不均匀会影响低对比度对象的可检测性，也被认为是困扰此类体积的最大强度投影(MIP)图像的斑马伪影的原因。虽然这些空间变化的噪声水平的根源在于螺旋扫描几何结构的特殊性，但它也强烈依赖于所采用的内插和重建算法。在这篇文章中，我们试图开发图像重建策略，从源头上消除或降低螺旋CT相对于常规CT噪声水平的不均匀。我们采取两种方法，独立的和协调一致的。我们论证并验证了基于傅立叶的纵向内插方法比标准的360LI和180LI方法产生更均匀的噪声比。我们还证明了基于傅立叶的扇形到并行反投影算法，作为扇束滤波反投影用于切片重建的替代方案，即使在使用180LI和360LI内插方法的情况下，也可以产生更均匀的噪声比。
Volumes reconstructed by standard methods from single‐slice helical computed tomography (CT) data have been shown to have noise levels that are highly nonuniform relative to those in conventional CT. These noise nonuniformities can affect low‐contrast object detectability and have also been identified as the cause of the zebra artifacts that plague maximum intensity projection (MIP) images of such volumes. While these spatially variant noise levels have their root in the peculiarities of the helical scan geometry, there is also a strong dependence on the interpolation and reconstruction algorithms employed. In this paper, we seek to develop image reconstruction strategies that eliminate or reduce, at its source, the nonuniformity of noise levels in helical CT relative to that in conventional CT. We pursue two approaches, independently and in concert. We argue, and verify, that Fourier‐based longitudinal interpolation approaches lead to more uniform noise ratios than do the standard 360LI and 180LI approaches. We also demonstrate that a Fourier‐based fan‐to‐parallel rebinning algorithm, used as an alternative to fanbeam filtered backprojection for slice reconstruction, also leads to more uniform noise ratios, even when making use of the 180LI and 360LI interpolation approaches.