Method for detecting flat polyps in the colon

Abstract

A method of formatting data for detecting flat polyps in a Computed Tomography Colonography, CTC, dataset comprising the steps of: extracting colon surface data, from the CTC dataset, within a sub-volume centred on a candidate polyp seed point; identifying individual sets of points corresponding to the candidate polyp's body and the candidate polyp's base within that sub-volume; projecting the set of points corresponding to the candidate polyp's body on to a tangent plane via a normal vector, wherein the normal vector is calculated from the best fitting plane to the set of points corresponding to the candidate polyp's base; isolating a new seed point for the candidate polyp from the projected data; locating the nearest surface point to the new seed in the extracted dataset above, and region-growing the surface ab initio from this point; identifying individual sets of points corresponding to the candidate polyp's body and the candidate polyp's base in the region-grown surface, and determining the normal vector from the best fitting plane to the set of points corresponding to the candidate polyp's base; using the normal vector determined in step vi) to slice the candidate structure in a number of different orientations; and generating a series of planes for each orientation, from which elliptical structures can be identified as representative of flat polyps.

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