Colon Centerline Calculation for CT Colonography
using Optimised 3D Topological Thinning
Robert J.T. Sadleir and Paul F. Whelan
Vision Systems Laboratory, School of Electronic Engineering,
Dublin City University, Dublin 9, Ireland.
{Robert.Sadleir, Paul.Whelan}@eeng.dcu.ie
Abstract
CT colonography is an emerging technique for colorec-
tal cancer screening. Using this technique virtual reality
models of the human colon are generated from an abdomi-
nal CT study of a suitably prepared patient. Manual navi-
gation through these models is a slow and tedious process.
It is possible to automate navigation by calculating the cen-
terline of the human colon. There are numerous well docu-
mented approaches for centerline calculation, most of these
have been developed as alternatives to 3D topological thin-
ning which is regarded as being far too computationally
intensive for use with large volumetric datasets. This pa-
per describes a fully automated, optimised version of 3D
topological thinning that has been specifically developed
for calculating the centerline of the human colon. This al-
gorithm is fast, portable and robust. Initial tests have been
performed on real patient data and the results are promis-
ing.
1. Introduction
Colorectal cancer is a major cause of cancer related death
in developed countries. Statistics published by the National
Cancer Registry of Ireland (NCRI) [14] indicate that colon
cancer accounted for 9% of all cancer cases diagnosed in
1997, second only to non-melanoma skin cancer (36%).
Colorectal cancer can be prevented if precursor polyps are
detected early in their course and successfully resected.
Regular screening is required in order to detect the presence
of colorectal polyps. At present the most sensitive screen-
ing technique is conventional colonoscopy. This involves
an endoscopic examination of the colonic mucosa using an
instrument known as a colonoscope.
There are several problems associated with conventional
colonoscopy. The patient must undergo complete bowel
evacuation prior to t