Domain-Based Analysis of Colon Polyp in CT Colonography Using Image-Processing Techniques

Abstract

Background: The purpose of the research was to improve the polyp detection accuracy in CT Colonography (CTC)<br />through effective colon segmentation, removal of tagged fecal matter through Electronic Cleansing (EC), and measuring<br />the smaller polyps. Methods: An improved method of boundary-based semi-automatic colon segmentation with the<br />knowledge of colon distension, an adaptive multistep method for the virtual cleansing of segmented colon based on<br />the knowledge of Hounsfield Units, and an automated method of smaller polyp measurement using skeletonization<br />technique have been implemented. Results: The techniques were evaluated on 40 CTC dataset. The segmentation<br />method was able to delineate the colon wall accurately. The submerged colonic structures were preserved without<br />soft tissue erosion, pseudo enhanced voxels were corrected, and the air-contrast layer was removed without losing<br />the adjacent tissues. The smaller polyp of size less than validated qualitatively and quantitatively. Segmented colons were validated through volumetric overlap computation,<br />and accuracy of 95.826±0.6854% was achieved. In polyp measurement, the paired t-test method was applied to compare<br />the difference with ground truth and at α=5%, t=0.9937 and p=0.098 was achieved. The statistical values of TPR=90%,<br />TNR=82.3% and accuracy=88.31% were achieved. Conclusion: An automated system of polyp measurement has been<br />developed starting from colon segmentation to improve the existing CTC solutions. The analysis of domain-based<br />approach of polyp has given good results. A prototype software, which can be used as a low-cost polyp diagnosis tool,<br />has been developed.