标题： 基于模型的迭代重建结合空间自适应条纹权重在宽锥体心脏CT中的应用 显示英文标题

标题： Model Based Iterative Reconstruction With Spatially Adaptive Sinogram Weights for Wide-Cone Cardiac CT

摘要： 随着配备大锥角的CT扫描仪的引入，宽覆盖探测器现在提供了一个理想的冠状动脉CT扫描平台，允许在单次旋转中实现全心脏成像。 在这类扫描仪上，尽管半扫描数据严格来说足以生成具有最佳时间分辨率的图像，但获取相当于完整360度旋转的数据对于宽锥重建是有益的，并且不会显著增加额外的辐射剂量。 将基于模型的迭代重建（MBIR）算法应用于心脏已显示出对冠状动脉CT图像质量有显著提升。 然而，在大锥角几何结构下对心脏成像会导致明显冲突的数据使用考虑。 一方面，除了使用最快可用的扫描仪旋转速度外，通常会使用最小完整的180度加扇形角的数据集来尽量减少心脏和呼吸运动的影响。 另一方面，完整的360度采集有助于更好地应对与宽锥半扫描数据采集相关的缺失频率和不完整投影的挑战。 在本文中，我们开发了一种空间自适应sinogram权重MBIR算法（SAW-MBIR），旨在实现半扫描和全扫描重建的优点，以最大化心脏区域的时间分辨率，同时在整个宽区域探测器覆盖的体积内提供稳定的结果。 SAW-MBIR中的空间自适应sinogram权重根据投影角度和重建体素位置，选择性地从sinogram的全扫描和半扫描部分执行反向投影。 我们通过应用到全心脏冠状动脉CT临床数据的SAW-MBIR实验结果表明，总体时间分辨率与半扫描匹配，而整个体积的图像质量与全扫描MBIR相当。 显示英文摘要

摘要： With the recent introduction of CT scanners with large cone angles, wide coverage detectors now provide a desirable scanning platform for cardiac CT that allows whole heart imaging in a single rotation. On these scanners, while half-scan data is strictly sufficient to produce images with the best temporal resolution, acquiring a full 360 degree rotation worth of data is beneficial for wide-cone image reconstruction at negligible additional radiation dose. Applying Model-Based Iterative Reconstruction (MBIR) algorithm to the heart has shown to yield significant enhancement in image quality for cardiac CT. But imaging the heart in large cone angle geometry leads to apparently conflicting data usage considerations. On the one hand, in addition to using the fastest available scanner rotation speed, a minimal complete data set of 180 degrees plus the fan angle is typically used to minimize both cardiac and respiratory motion. On the other hand, a full 360 degree acquisition helps better handle the challenges of missing frequencies and incomplete projections associated with wide-cone half-scan data acquisition. In this paper, we develop a Spatially Adaptive sinogram Weights MBIR algorithm (SAW-MBIR) that is designed to achieve the benefits of both half and full-scan reconstructions in order to maximize temporal resolution over the heart region while providing stable results over the whole volume covered with the wide-area detector. Spatially-adaptive sinogram weights applied to each projection measurement in SAW-MBIR are designed to selectively perform backprojection from the full and half-scan portion of the sinogram based on both projection angle and reconstructed voxel location. We demonstrate with experimental results of SAW-MBIR applied to whole-heart cardiac CT clinical data that overall temporal resolution matches half-scan while full volume image quality is on par with full-scan MBIR.