Suppr超能文献

基于任务的高质量锥束CT统计图像重建

Task-based statistical image reconstruction for high-quality cone-beam CT.

作者信息

Dang Hao, Stayman J Webster, Xu Jennifer, Zbijewski Wojciech, Sisniega Alejandro, Mow Michael, Wang Xiaohui, Foos David H, Aygun Nafi, Koliatsos Vassilis E, Siewerdsen Jeffrey H

机构信息

Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, United States of America.

出版信息

Phys Med Biol. 2017 Nov 1;62(22):8693-8719. doi: 10.1088/1361-6560/aa90fd.

Abstract

Task-based analysis of medical imaging performance underlies many ongoing efforts in the development of new imaging systems. In statistical image reconstruction, regularization is often formulated in terms to encourage smoothness and/or sharpness (e.g. a linear, quadratic, or Huber penalty) but without explicit formulation of the task. We propose an alternative regularization approach in which a spatially varying penalty is determined that maximizes task-based imaging performance at every location in a 3D image. We apply the method to model-based image reconstruction (MBIR-viz., penalized weighted least-squares, PWLS) in cone-beam CT (CBCT) of the head, focusing on the task of detecting a small, low-contrast intracranial hemorrhage (ICH), and we test the performance of the algorithm in the context of a recently developed CBCT prototype for point-of-care imaging of brain injury. Theoretical predictions of local spatial resolution and noise are computed via an optimization by which regularization (specifically, the quadratic penalty strength) is allowed to vary throughout the image to maximize local task-based detectability index ([Formula: see text]). Simulation studies and test-bench experiments were performed using an anthropomorphic head phantom. Three PWLS implementations were tested: conventional (constant) penalty; a certainty-based penalty derived to enforce constant point-spread function, PSF; and the task-based penalty derived to maximize local detectability at each location. Conventional (constant) regularization exhibited a fairly strong degree of spatial variation in [Formula: see text], and the certainty-based method achieved uniform PSF, but each exhibited a reduction in detectability compared to the task-based method, which improved detectability up to ~15%. The improvement was strongest in areas of high attenuation (skull base), where the conventional and certainty-based methods tended to over-smooth the data. The task-driven reconstruction method presents a promising regularization method in MBIR by explicitly incorporating task-based imaging performance as the objective. The results demonstrate improved ICH conspicuity and support the development of high-quality CBCT systems.

摘要

基于任务的医学成像性能分析是新成像系统开发中许多正在进行的工作的基础。在统计图像重建中,正则化通常以鼓励平滑度和/或清晰度的方式来制定(例如线性、二次或Huber惩罚),但没有明确的任务表述。我们提出了一种替代的正则化方法,其中确定一个空间变化的惩罚,以在三维图像的每个位置最大化基于任务的成像性能。我们将该方法应用于头部锥形束CT(CBCT)中基于模型的图像重建(MBIR,即惩罚加权最小二乘法,PWLS),重点关注检测小的、低对比度颅内出血(ICH)的任务,并在最近开发的用于脑损伤即时护理成像的CBCT原型的背景下测试该算法的性能。通过一种优化计算局部空间分辨率和噪声的理论预测,通过该优化允许正则化(具体而言,二次惩罚强度)在整个图像中变化,以最大化基于局部任务的可检测性指数([公式:见正文])。使用拟人化头部模型进行了模拟研究和测试台实验。测试了三种PWLS实现方式:传统(恒定)惩罚;为强制恒定点扩散函数(PSF)而导出的基于确定性的惩罚;以及为在每个位置最大化局部可检测性而导出的基于任务的惩罚。传统(恒定)正则化在[公式:见正文]中表现出相当强的空间变化程度,基于确定性的方法实现了均匀的PSF,但与基于任务的方法相比,每种方法的可检测性都有所降低,基于任务的方法将可检测性提高了约15%。在高衰减区域(颅底),这种改进最为明显,传统方法和基于确定性的方法往往会过度平滑数据。任务驱动的重建方法通过明确将基于任务的成像性能作为目标,在MBIR中提出了一种有前景的正则化方法。结果表明ICH的可见性得到了改善,并支持了高质量CBCT系统的开发。

文献AI研究员

20分钟写一篇综述,助力文献阅读效率提升50倍。

立即体验

用中文搜PubMed

大模型驱动的PubMed中文搜索引擎

马上搜索

文档翻译

学术文献翻译模型,支持多种主流文档格式。

立即体验