Skeleton-based 3D computer-aided detection of colonic polyps

Abstract

In this paper, we propose a new computer aided detection (CAD) technique to utilize both global and local shape information of the colon wall for detection of colonic polyps. Firstly, the whole colon wall is extracted by our mixture-based image segmentation method. This method uses partial volume percentages to represent the distribution of different materials in each voxel, so it provides the most accurate information on the colon wall, especially the mucosa layer. Local geometrical measure of the colon mucosa layer is defined by the curvature and gradient information extracted from the segmented colon-wall mixture data. Global shape information is provided by applying an improved linear integral convolution operation to the mixture data. The CAD technique was tested on twenty patient datasets. The local geometrical measure extracted from the mixture segmentation represents more accurately the polyp variation than that extracted from conventional label classification, leading to improved detection. The added global shape information further improves the polyp detection.

Reduction of false positives by internal features for polyp detection in CT‐based virtual colonoscopy

“…Therefore, the combination of both the traditional and the modified local shape measures in these filters is expected to reduce the miss classifications. Both Filter 1 and Filter 2 are very simple and work very well [42]. Experimental studies in this work show that both Filter 1 and Filter 2 can eliminate up to 80% miss classifications.…”

“…It is noted that both the traditional and the smoothed local curvatures have their complementary properties as described above [42]. A typical polyp shall show some geometrical attributes by the local and global GS measures.…”

“…It is difficult, based only on the local geometrical shape information [16,18,26], to pick a complete protuberance section from the colon wall. By including a modified shape-index measure [42], which is derived from a smoothed version of the local curvatures as described above, the difficulty can be mitigated, i.e., a complete protuberance section of an irregular polyp candidate can be detected. Based on both the traditional and the modified local shapeindex measures, a clustering algorithm is developed to find suspicious areas or patches on the segmented colon mucosa layer [39,40].…”

“…Based on the observation [9,42,46], the density values within a polyp change gradually and smoothly from the center to its border. This attribute is reflected by the convergence of the triple-element vectors toward the corner (1.0, 1.0, 1.0) in the 3D presentation of Figure 7(d).…”

An Improved Electronic Colon Cleansing Method for Detection of Colonic Polyps by Virtual Colonoscopy

“…One CAD measure is the surface-or shape-based approach [47]. It combines both the traditional local principal curvature measures and a modified or smoothed version (which is called global principal curvature measures) to quantify the shape of the extracted mucosa layers from both ECC methods.…”