Dual-energy Electronic-cleansing CT Colonography for Colon Cancer Screening

描述（由申请人提供）：筛查是目前早期发现结肠癌的最有效方法。计算机断层结肠成像（CTC）或虚拟结肠镜检查已成为非侵入性结肠癌筛查的有效技术，可替代光学结肠镜检查（OC）。然而，目前的CTC检查需要检查前的泻药肠道准备，基本上与OC所需的相同。在CTC检查前与严格的泻药肠道准备相关的感觉不适和不便已被确定为广泛接受结肠筛查的主要障碍。将非泻药肠道准备应用于CTC检查的主要技术障碍是缺乏用于在CTC图像中减去标记的粪便物质的有效电子清洁（EC）方案，因为在当前EC方法中遇到的清洁伪影太严重而不能允许诊断质量的非泻药CTC图像。双能量CT（deCT）是一种新的成像技术，它允许根据不同能量下两次同步CT采集得出的CT衰减值来区分材料。非泻药双能CTC（deCTC），即，将deCT应用于非泻药CTC图像采集，具有显著提高EC质量的潜力。 在本项目中，我们将开发一种用于非泻药deCTC的EC方案，称为双能量EC（deEC），其中患者将接受非泻药肠道准备检查，并使用deCT扫描仪进行成像。在图像采集后，所提出的deEC方案将通过在双能量背景下开发的一组新颖的图像处理方法有效地去除CTC图像中结肠中的残留粪便物质。在deCTC中的材料区分的能力提供了一个新的维度，用于消除当前EC方法中存在的主要清洗伪影，从而提供诊断质量的CTC图像。出于评价目的，我们将建立非泻药DE-CTC数据库。将在体模研究、手动清洗研究、息肉计算机辅助检测（CAD）研究和观察员研究中评价拟议DE-EC方案的质量和性能。这项研究是创新的，因为尚未尝试过非泻药deCTC及其deEC方案的开发。 拟议的deEC方案的成功开发和验证将为放射科医生提供用于检测结肠癌的诊断质量的清洁CTC图像，并且将使患者从关于结肠筛查的主要担忧中解脱出来。这种deEC辅助的非泻药deCTC检查可以显著提高筛查依从性、安全性和结肠癌筛查的能力。因此，拟议的研究将大大提高结肠息肉和癌症的筛查率和早期发现。

DESCRIPTION (provided by applicant): Screening is currently the most effective way for early detection of colonic cancer. Computed tomographic colonography (CTC), or virtual colonoscopy, has become an effective technique for non-invasive colon cancer screening that can be an alternative to optical colonoscopy (OC). However, current CTC examinations require pre-examination cathartic bowel preparation, essentially identical to that required for OC. The perceived discomfort and inconvenience associated with the rigorous cathartic bowel preparation before a CTC examination has been identified as the main barrier to wide acceptance of colon screening. The main technical barrier in applying non-cathartic bowel preparation to CTC examination is the lack of an effective electronic cleansing (EC) scheme for subtraction of tagged fecal materials in CTC images, because the cleansing artifacts encountered in current EC methods are too severe to allow non-cathartic CTC images of diagnostic quality. Dual-energy CT (deCT) is a new imaging technique that allows materials differentiation based on CT attenuation values derived from two synchronous CT acquisitions at different energies. Non-cathartic dual-energy CTC (deCTC), i.e., applying deCT to non-cathartic CTC image acquisition, has the potential significantly to improve the quality of EC. In this project, we will develop an EC scheme for non-cathartic deCTC, denoted as dual-energy EC (deEC), in which patients will be examined with non-cathartic bowel preparation and imaged with a deCT scanner. After image acquisition, the proposed deEC scheme will effectively remove the residual fecal materials in the colon in CTC images by a set of novel image processing methods developed in a dual-energy context. The capability of material differentiation in deCTC provides a new dimension for obviating the major cleansing artifacts existing in current EC methods, and thus provides CTC images of diagnostic quality. For evaluation purposes, we will establish a non-cathartic DE-CTC database. The quality and performance of the proposed DE-EC scheme will be evaluated in a phantom study, a manual cleansing study, a computer-aided detection (CAD) of polyps study, and an observer study. This research is innovative in that the non-cathartic deCTC and the development of its deEC scheme have not yet been attempted. The successful development and validation of the proposed deEC scheme will provide radiologists with cleansed CTC images of diagnostic quality for detecting colon cancer, and it will release the patients from the main concern regarding colon screening. Such an deEC-aided non-cathartic deCTC examination could substantially increase the screening compliance, safety, and the capacity for colon cancer screening. Thus, the proposed research will substantially raise the screening rate and the early detection of colonic polyps and cancers.