Limited Angle Image Reconstruction

描述(由申请人提供)：数字乳房断层合成(DBT)正被许多医疗设备制造商所追求，因为其有限的断层扫描能力直接解决了全场数字乳房X光摄影(FFDM)的一个主要缺点。也就是说，由于投影成像的性质，可能会出现假阳性，因为重叠的正常组织结构有时类似于肿瘤，而发生假阴性是因为肿瘤可能被正常组织掩盖--特别是在年轻女性致密的乳房中。许多关于DBT的研究已经进行或正在进行，一般意义上来说，DBT确实有助于肿瘤的检测，但在微钙化的检测和表征方面，它的表现可能不如FFDM，这些都是可以间接指示恶性肿瘤的成像任务。本研究旨在优化DBT的图像重建算法。我们的初步结果已经表明，例如，DBT中的微钙化成像受到图像重建算法次优的限制：我们的初步研究已经在微钙化信噪比方面产生了两倍的增益。由于目前用于DBT的许多迭代图像重建(IIR)算法基本上是从核医学成像中借鉴而来的，几乎没有修改，因此显然有很大的空间来为DBT量身定制IIR图像质量。事实上，DBT设备已经在进行使用次优图像重建算法的临床试验，这增加了拟议研究的紧迫性。这项研究的目的是表明，通过量身定制IIR在DBT中的应用，可以显著提高DBT的临床实用性。该研究的目的是：(1)构建一个IIR框架，解决有限角度扫描和固定剂量的图像噪声和投影数之间的权衡。(2)基于优化的设计方法对投影截断具有较强的鲁棒性。(3)开发DBT投影的数据一致性检查和自动校正技术。(4)为算法优化设计了DBT图像的图像质量指标。(5)使用人工观察者对算法性能进行评估。

DESCRIPTION (provided by applicant): Digital breast tomosynthesis (DBT) is being pursued by many medical device manufacturers, because its limited tomographic capability directly addresses a major short-coming of full-field digital mammography (FFDM). Namely, due to the nature of projection imaging, false positives can occur because overlapping normal tissue structures sometimes resemble tumors, and false negatives happen because tumors may be masked by normal tissue - particularly in dense breasts of young women. Many studies on DBT have been performed or ongoing and the general sense is that DBT does help for tumor detection, but it may perform worse than FFDM on microcalcification detection and characterization, which are imaging tasks that can indirectly indicate malignancy. The proposed research aims at optimizing image reconstruction algorithms for DBT. Our preliminary results indicate already, for example, that microcalcification imaging in DBT is limited by the sub-optimality of the image reconstruction algorithm: our initial investigations already yield a factor-of-two gain in microcalcification signal-to-noise ratio. As many of the current iterative image reconstruction (IIR) algorithms employed in DBT were essentially borrowed, with little modification, from nuclear medicine imaging there is clearly room for large gains in image quality for tailoring IIR to DBT. The fact that DBT devices are already undergoing clinical trials with sub-optimal image reconstruction algorithms increases the urgency of the proposed research. The goal of the research is to show that clinical utility of DBT can be enhanced significantly by tailoring IIR to application in DBT. The aims of the proposed research are: (1) Construct a framework for IIR addressing the limited angular scan and fixed-dose trade-off of image noise and number of projections. (2) Design optimization-based approaches robust against projection truncation. (3) Develop data consistency checks and automated correction techniques for DBT projections. (4) Design image quality metrics of DBT images for algorithm optimization. (5) Evaluate algorithm performance with human observers.