Cone-beam artifact evaluation of the factorization method.
Cone-beam artifact evaluation of the factorization method.
复制标题
因子分解方法的锥束伪影评估。
DOI：
10.1118/1.3577743
复制
发表时间：
2011
期刊：
影响因子：
3.8
通讯作者：
Noo,Frédéric
中科院分区：
文献类型：
--
作者：
Dennerlein,Frank;Noo,Frédéric
目的研究最近提出的用于圆锥束计算机断层扫描图像重建的因子分解方法的CB伪影行为。这项调查是在一个典型的C形臂的几何形状，涉及模拟数据，并首次也幻影和临床CB数据采集与市售angiographic system.MethodsThe CB伪影水平首先测量使用定量数字的优点，计算从重建的数学FORBILD头幻影和修改后的磁盘幻影。然后，作者展示了从物理胸部模型和临床头部数据集重建的图像质量的视觉评估。因子分解方法的性能主要与短扫描FDK的性能进行比较，但作者还显示了全扫描FDK和虚拟PI线BPF方法模拟研究的结果，作为基准。结果定量地，两种FDK方法的FORBILD头部模型重建在距离扫描平面约9 cm的轴向切片中显示出高达1.2%的空间平均偏差，其被放置在穿过体模的中心切片下方4cm处。短扫描FDK方法和虚拟PI线BPF方法的伪影水平明显取决于扫描方向。因子分解方法可以显著降低这种依赖性以及重建偏差。它还显示了视觉上的改善质量的临床图像相比，短扫描FDK，特别是接近脊柱和在临床datasets.ConclusionsThe分解方法的颅下区域的重建偏差明显低于FDK方法，是最不敏感的扫描方向之间的所有考虑短扫描方法。包含在真实的数据集中的数据不一致性，如散射、射束硬化或数据截断，对因子分解结果的影响很小。因此，在根据真实的和模拟数据进行重建时，因子分解方法产生的图像质量优于短扫描FDK，尽管代价是一些轻微的定向高频伪影，这些伪影在轴向切片中大多可见。
PurposeThe authors investigate the CB artifact behavior of the factorization approach recently suggested for image reconstruction in circular cone‐beam computed tomography. This investigation is carried out in a typical C‐arm geometry and involves simulated data and for the first time also phantom and clinical CB data acquired with a commercially available angiographic system.MethodsThe CB artifact level is first measured using quantitative figures‐of‐merit that are computed from the reconstructions of the mathematical FORBILD head phantom and of a modified disk phantom. The authors then show reconstructions from a physical thorax phantom and clinical head data sets for a visual assessment of image quality. The performance of the factorization method is primarily compared to that of short‐scan FDK, but the authors also show the results obtained with the full‐scan FDK and the virtual PI‐line BPF method for the simulation studies, as a benchmark.ResultsQuantitatively, the FORBILD head phantom reconstructions of both FDK methods show a spatially averaged bias of up to 1.2% in the axial slices about 9 cm away from the plane of the scan, which is placed 4 cm below the central slice through the phantom. The artifact level for the short‐scan FDK method and the virtual PI‐line BPF method noticeably depends on the scan orientation. The factorization approach can significantly reduce both, this dependency as well as the reconstruction bias. It also shows visually an improved quality of the clinical images compared to short‐scan FDK, particularly close to the spine and in the subcranial regions of the clinical data sets.ConclusionsThe factorization approach comes with noticeably lower reconstruction bias than the FDK methods and is least sensitive to the scan orientation among all considered short‐scan methods. The data inconsistencies contained in the real data sets, such as scatter, beam hardening, or data truncation, show only little impact on the factorization results. Hence, in both, reconstructions from real and simulated data, the factorization method yields better image quality than short‐scan FDK, albeit at the cost of some slight, directed high‐frequency artifacts that are mostly visible in axial slices.