Analysis of colon curvatures toward optimizing colonoscopy examinations

Purpose: Colonoscopy is a complex procedure with considerable variation among patients, requiring years of experience to become proficient. Understanding the curvature of colons could enable practitioners to be more effective. The purpose of this research is to develop methods to analyze the curvature of patients’ colons, and compare key segments of colons between supine and prone positions.  Methods: The colon lumen in CT scans of 42 patients were segmented. The following steps were automated by Python scripts in the 3D Slicer application: a set of center points along the colon were generated, and a curve was fit to those points. By identifying local maximums and local minimums in curvature, curves were defined between two local curvature minimums. The angle of each curve was calculated over the distance of curves.  Results: This process was used to identify and analyze curves on the colon centerline in different patient positions. On average, there are 32.63±0.83 curves in supine position and 31.24±0.80 in prone. In the supine position the curves turn an average of 77.80±2.25 degrees, and 75.88±1.87 degrees in prone. Graphically, there are observable differences between positions for curves of specific magnitudes. Conclusion: This process can quantify the curvature of colons, and could be adapted to consider other patient groups. Descriptive statistics indicate supine position has more curves in the descending colon, and prone has sharper curves in the descending colon. These preliminary results motivate further work with a larger sample size for statistical analysis, which may reveal significant differences.