title: Virtual colon flattening method based on colonic outer surface.
abstract: Virtual colon flattening (VF) is a minimally invasive viewing mode used to detect colorectal polyps on the colonic inner surface in virtual colonoscopy. Compared with conventional colonoscopy, inspecting a flattened colonic inner surface is faster and results in fewer uninspected regions. Unfortunately, the deformation distortions of flattened colonic inner surface impede the performance of VF. Conventionally, the deformation distortions can be corrected by using the colonic inner surface. However, colonic curvatures and haustral folds make correcting deformation distortions using only the colonic inner surface difficult. Therefore, we propose a VF method that is based on the colonic outer surface. The proposed method includes two novel algorithms, namely, the colonic outer surface extraction algorithm and the colonic outer surface-based distortion correction algorithm. Sixty scans involving 77 annotated polyps were used for the validation. The flattened colons were independently inspected by three operators and then compared with three existing VF methods. The correct detection rates of the proposed method and the three existing methods were 79.6%, 67.1%, 71.9%, and 72.7%, respectively, and the false positives per scan were 0.16, 0.32, 0.21, and 0.26, respectively. The experimental results demonstrate that our proposed method has better performance than existing methods that are based on the colonic inner surface.
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lu
authors.affiliation: School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: junzhao@sjtu.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
mesh_terms: D000465:Algorithms; D000704:Analysis of Variance; D003106:Colon / Q000000981:diagnostic imaging* / Q000473:pathology*; D003110:Colonic Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005189:False Positive Reactions; D006801:Humans; D021621:Imaging, Three-Dimensional; D008962:Models, Theoretical; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Colonic outer surface; Deformable distortion correction; Virtual colon flattening