Development of a Cathartic-Free Colorectal Cancer Screening Test Using Virtual Colonoscopy: A Feasibility Study

Abstract

Image processing tools combining thresholding, expansion, and convolution were the most useful for stool subtraction. Laxative-free colon examinations using barium for stool labeling can be performed at CT colonography with or without stool subtraction with high accuracy. Further study is warranted.

CT colonography for synchronous colorectal lesions in patients with colorectal cancer: initial experience

“…The former of these problems may become less of an issue now that routine use of fluid/faecal tagging has been introduced, and may improve further with software enhancements like electronic subtraction negating the need for onerous bowel preparation [28]. These improvements make prep-less CTC a reality [29]. Another technical advance might be the reported combination of CTC with PET that enables the malignant potential of polyps to be further characterised [30,31], although this combined technique is still in its infancy.…”

Virtual tagging for laxative‐free CT colonography: Pilot evaluation

“…However, several studies have demonstrated that conventional methods that have been developed for fluid-tagging CTC tend to fail in lfCTC, and that new approaches are needed. [8][9][10]20,[36][37][38] Unless suitable visualization and detection tools are developed for lfCTC, the clinical potential of lfCTC might never be realized. Our study represents one of the very first efforts toward developing such interpretation tools.…”

“…On the other hand, attempts to segment tagged regions more precisely with a low CT number threshold can segment parts of pseudoenhanced native soft tissue, including polyps, as tagged region. 9,10 In this study, we hypothesized that the identification of poorly tagged residual materials and partial-volume artifacts could be improved in lfCTC by virtual tagging of such artifacts. We note that the observed radiodensity of tagged materials tends to be diluted by the partial-volume effect ͑PVE͒ that occurs within the material interface between lumen air and nonair materials, and that such diluted tagged materials appear similar to soft tissue ͓Figs.…”

Single-center study comparing computed tomography colonography with conventional colonoscopy

“…Results from this study highlight the importance of bowel preparation although, in the future, it may be possible to reliably differentiate fecal material from polyps using fecal tagging [10] , "electronic cleansing" of colonic fluid [16] or contrast-enhanced studies [27] . Other helpful developments may also include new fecal subtraction algorithms [28] , workstation modifications to facilitate polyp detection [29] , improved software and new training prog rams for radiologists [30] .…”