IEEE Trans Biomed Eng. 2013 Nov;60(11):3036-45. doi: 10.1109/TBME.2013.2262046. Epub 2013 May 7.
CT colonography (CTC) is one of the recommended methods for colorectal cancer screening. The subject's preparation is one of the most burdensome aspects of CTC with a cathartic bowel preparation. Tagging of the bowel content with an oral contrast medium facilitates CTC with limited bowel preparation. Unfortunately, such preparations adversely affect the 3-D image quality. Thus far, data acquired after very limited bowel preparation were evaluated with a 2-D reading strategy only. Existing cleansing algorithms do not work sufficiently well to allow a primary 3-D reading strategy. We developed an electronic cleansing algorithm, aimed to realize optimal 3-D image quality for low-dose CTC with 24-h limited bowel preparation. The method employs a principal curvature flow algorithm to remove heterogeneities within poorly tagged fecal residue. In addition, a pattern recognition-based approach is used to prevent polyp-like protrusions on the colon surface from being removed by the method. Two experts independently evaluated 40 CTC cases by means of a primary 2-D approach without involvement of electronic cleansing as well as by a primary 3-D method after electronic cleansing. The data contained four variations of 24-h limited bowel preparation and was based on a low radiation dose scanning protocol. The sensitivity for lesions ≥ 6 mm was significantly higher for the primary 3-D reading strategy (84%) than for the primary 2-D reading strategy (68%) (p = 0.031). The reading time was increased from 5:39 min (2-D) to 7:09 min (3-D) (p = 0.005); the readers' confidence was reduced from 2.3 (2-D) to 2.1 (3-D) ( p = 0.013) on a three-point Likert scale. Polyp conspicuity for cleansed submerged lesions was similar to not submerged lesions (p = 0.06). To our knowledge, this study is the first to describe and clinically validate an electronic cleansing algorithm that facilitates low-dose CTC with 24-h limited bowel preparation.
CT 结肠成像（CTC）是结直肠癌筛查的推荐方法之一。受检者的准备工作是 CTC 最繁琐的方面之一，需要进行通便肠道准备。口服对比剂对肠道内容物进行标记有助于在有限的肠道准备下进行 CTC。不幸的是，这种准备会对 3D 图像质量产生不利影响。到目前为止，仅使用二维阅读策略评估了在非常有限的肠道准备下获得的数据。现有的清洁算法效果不佳，无法实现主要的 3D 阅读策略。我们开发了一种电子清洁算法，旨在在 24 小时有限肠道准备下实现低剂量 CTC 的最佳 3D 图像质量。该方法采用主曲率流算法去除标记不良的粪便残留物中的异质性。此外，还采用基于模式识别的方法来防止结肠表面的息肉样突起被该方法去除。两位专家分别独立地对 40 例 CTC 病例进行评估，一种是不涉及电子清洁的主要二维方法，另一种是电子清洁后的主要三维方法。该数据包含四种不同的 24 小时有限肠道准备，基于低辐射剂量扫描方案。主要三维阅读策略的病变≥6mm 的灵敏度（84%）明显高于主要二维阅读策略（68%）（p=0.031）。阅读时间从 5:39 分钟（二维）增加到 7:09 分钟（三维）（p=0.005）；读者的信心从 2.3（二维）降低到 2.1（三维）（p=0.013），采用三点李克特量表。清洁后的浸没病变和未浸没病变的息肉显影相似（p=0.06）。据我们所知，这是首次描述和临床验证一种电子清洁算法，该算法可促进 24 小时有限肠道准备的低剂量 CTC。
