Automatic correction of level set based subvoxel accurate centerlines for virtual colonoscopy

Virtual colonoscopy (VC) is becoming a more prevalent way to diagnose colon cancer. One of the critical elements in detecting cancerous polyps using VC in conjunction with computer-aided detection is that the colon centerline be determined accurately. The amount of colonic distention can vary from patient to patient, which may cause loops and multiple disconnected segments to appear in the colon segmentation. These variations have caused previous centerline algorithms to fail to capture a complete and accurate centerline for all colons. We have developed an automatic method to determine from a CT VC scan a subvoxel accurate centerline, which is accurate even in cases of over- or underdistended colons. We have demonstrated successfully the effectiveness of our algorithm on 50 cases, half of which resulted in erroneous solutions by previous centerline algorithms