Electronic cleansing is an image post processing technique in which the tagged colonic content is subtracted from colon using CTC images. There are post processing artefacts, like: 1) soft tissue degradation; 2) incomplete cleansing; 3) misclassification of polyp due to pseudo enhanced voxels; and 4) pseudo soft tissue structures. The objective of the study was to subtract the tagged coloniccontent without losing the soft tissue structures. This paper proposes a novel adaptive method to solve the first three problems using a multi-step algorithm. It uses a new edge model-based method which involves colon segmentation, priori information of Hounsfield units (HU) of different colonic contents at specific tube voltages, subtracting the tagging materials, restoring the soft tissue structures based on selective HU, removing boundary between air-contrast, and applying a filter to clean minute particles due to improperly tagged endoluminal fluids which appear as noise. The main finding of the study was submerged soft tissue structures were absolutely preserved and the pseudo enhanced intensities were corrected without any artifact. The method was implemented with multithreading for parallel processing in a high performance computer. The technique was applied on a fecal tagged dataset (30 patients) where the tagging agent was not completely removed from colon. The results were then qualitatively validated by radiologists for any image processing artifacts.
This would seem to eliminate the need for extensive bowel cleansing; instead a dye would be consumed that would stain fecal matter, which could then be electronically subtracted from the image. Imaging ("virtual") colonoscopy is an alternative to the “real-life” version. Advantages being that it is less invasive and eliminates most of the potential side effects; negatives are that you would need regular colonoscopy if the imaging found something, and it is not offered at many locations. Then there is the radiation exposure, and whether or not you are comfortable with imaging accuracy vs. direct visualization (although some studies put accuracy as high, but those were with bowel cleansing).
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