Robust Visualization in CT Colonography

Computed-Tomography Colonoscopy (CTC) refers to visualization of the colon surface (lumen) by radiologists following an abdominal CT scan of prepped patients. Removal of colonic polyps is performed by a minimally- invasive procedure known as Optical Colonoscopy (OC). Through a sequence of image analysis steps, a three- dimensional (3D) representation of the colon can be constructed, which is then visualized by radiologists, using a virtual camera, in order to examine the colon surface for abnormalities and polyps. A proper synchronization between CTC for early detection of polyps and OC for their removal is the most effective and economical approach to prevent colon cancer, which has over 95% rate of recovery with early detection. With improved efficacy and safety of the procedure, debate regarding the acceptance of CTC as a clinical and reimbursable procedure for early detection of colon cancer has evolved in its favor. However, the limitations of current CTC visualization methods in terms of distortions and large false positive rates, coupled with the fact that only a very small segment of the population undergoes OC or CT screening, means that only about 4 out of 10 colorectal cancers are found at an early stage. Reduction of false positive and proper synchronization of the CTC-OC cycle hold promise for combating colorectal cancer. This Phase 1 project introduces a novel CTC visualization which is entirely model-based, enabling quantifying the performance with respect to the topology of the colon and the types and size of colonic polyps. The approach uses a virtual camera rig arranged in a specific pattern within the colon’s inner surface (lumen) and will be denoted by “Fly-In” and would be abbreviated by FI. This rig provides visualizes the lumen and presents it as a sheet (filet) without distortion. This arrangement of virtual cameras is adaptable to topological variations in the 3D tubular shape (e.g., constrictions and expansions, bends and deformations) and the textural content of the lumen. Thus FI transforms the 3D tubular object into a sheet/filet without distortions. Specific Aims: This Phase 1 will have three main Specific Aims: 1) Implementation of the FI method. A theoretical framework for the image formation in FI will be established to relate the lumen details to the number of the virtual cameras in the rig to be used; focus would be on detecting and classification of all polyps above 5 mm in size. 2) Developing an automatic polyp methods for the method, using curvature and planar texture measures as well, in order to detect various type of polyps. 3) Evaluate the FI method on synthetic and retrospective scans of up to 50 CTC patients and comparing its performance against traditional CTC methods such as Fly-Through (FT) and Fly-Over (FO) and Colon Flattening (Filet approach). With successful execution of Phase 1, the investigators will move into clinical testing using a multi-center study, and will pursue NIH Phase II funding and other venues for commercialization.Project Narrative Colorectal cancer (CRC) is the second leading cause of cancer death (when combining men and women statistics of the disease) in the United States and is the third most commonly diagnosed cancer, with less than 40% of the eligible population taking advantage of current screening methods. Early detection and removal of colonic polyps using Optical Colonoscopy is an effective approach to combat colon cancer. Computed- Tomography Colonography (CTC) conducted on prepped patients is a non-invasive approach for early detection of colonic polyps. With proper synchronization between Optical Colonoscopy (OC) and CTC, an economic and robust approach for early detection and treatment of colon cancer is within reach. The proposed Fly-In CTC technology aims to provide unprecedented accuracy (in terms of sensitivity and specificity) of polyp detection by the radiologists and the computer.