论文标题
神经计算机断层扫描
Neural Computed Tomography
论文作者
论文摘要
尽管快速获取了单个观点,但在获取一组预测期间的运动可能会导致计算机断层扫描重建的大量运动伪影。在诸如心脏成像之类的情况下,运动可能是不可避免的,并且评估运动可能具有临床感兴趣。通常,通过开发更快的龙门旋转或使用测量和/或估计位移的算法来实现以减少运动伪影的重建图像。但是,由于身体限制以及估计/测量非刚性,时间变化和患者特定的运动的挑战,这些方法的成功率有限。我们提出了一个新颖的重建框架,即Neururct,以生成无运动伪影的时间分辨图像。我们的方法采用神经隐式方法,不需要对基本运动的估计或建模。取而代之的是,边界使用签名的距离度量和神经隐式框架表示。我们利用``分析''来识别与获得的正弦图以及空间和时间一致性约束一致的解决方案。我们说明了在三个逐渐复杂的场景中神经效应的实用性:小圆圈的翻译,椭圆直径的类似心跳的变化以及复杂的拓扑变形。与使用均方体误差和骰子指标相比,Neururct在没有超参数调整或更改体系结构的情况下为所有三个动作提供了高质量的图像重建。
Motion during acquisition of a set of projections can lead to significant motion artifacts in computed tomography reconstructions despite fast acquisition of individual views. In cases such as cardiac imaging, motion may be unavoidable and evaluating motion may be of clinical interest. Reconstructing images with reduced motion artifacts has typically been achieved by developing systems with faster gantry rotation or using algorithms which measure and/or estimate the displacements. However, these approaches have had limited success due to both physical constraints as well as the challenge of estimating/measuring non-rigid, temporally varying, and patient-specific motions. We propose a novel reconstruction framework, NeuralCT, to generate time-resolved images free from motion artifacts. Our approaches utilizes a neural implicit approach and does not require estimation or modeling of the underlying motion. Instead, boundaries are represented using a signed distance metric and neural implicit framework. We utilize `analysis-by-synthesis' to identify a solution consistent with the acquired sinogram as well as spatial and temporal consistency constraints. We illustrate the utility of NeuralCT in three progressively more complex scenarios: translation of a small circle, heartbeat-like change in an ellipse's diameter, and complex topological deformation. Without hyperparameter tuning or change to the architecture, NeuralCT provides high quality image reconstruction for all three motions, as compared to filtered backprojection, using mean-square-error and Dice metrics.