title: Postprocessing techniques of CT colonography in detection of colorectal carcinoma.
abstract: OBJECTIVE
  To evaluate the value of postprocessing techniques of CT colonography, including multiplanar reformation (MPR), virtual colonoscopy (VC), shaded surface display (SSD) and Raysum, in detection of colorectal carcinomas.
  
  
  METHODS
  Sixty-four patients with colorectal carcinoma underwent volume scanning with spiral CT. MPR, VC, SSD and Raysum images were obtained by using four kinds of postprocessing techniques in workstation. The results were comparatively analyzed according to circumferential extent, lesion length and pathology pattern of colorectal carcinomas. All diagnoses were proved pathologically and surgically.
  
  
  RESULTS
  The accuracy of circumferential extent of colorectal carcinoma determined by MPR, VC, SSD and Raysum was 100.0%, 82.8%, 79.7% and 79.7%, respectively. There was a significant statistical difference between MPR and VC. The consistent rate of lesion length was 89.1%, 76.6%, 95.3% and 100.0%, respectively. There was a statistical difference between VC and SSD. The accuracy of discriminating pathology pattern was 81.3%, 92.2%, 71.9% and 71.9%, respectively. There was a statistical difference between VC and SSD. MPR could determine accurately the circumference of colorectal carcinoma, Raysum could determine the length of lesion more precisely than SSD, VC was helpful in discriminating pathology patterns.
  
  
  CONCLUSIONS
  MPR, VC, SSD and Raysum have advantage and disadvantage in detection of colorectal carcinoma, use of these methods in combination can disclose the lesion more accurately.
authors.affiliation: Department of Radiology, Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, Guangdong Province, China. myluo@yahoo.com.cn
authors.forename: Ming-Yue
authors.initials: MY
authors.lastname: Luo
authors.forename: Hong
authors.initials: H
authors.lastname: Shan
authors.forename: Li-Qing
authors.initials: LQ
authors.lastname: Yao
authors.forename: Kang-Rong
authors.initials: KR
authors.lastname: Zhou
authors.forename: Wen-Wei
authors.initials: WW
authors.lastname: Liang
mesh_terms: D000328:Adult; D000368:Aged; D023881:Colonography, Computed Tomographic / Q000379:methods* / Q000592:standards; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results