title: Flat colorectal neoplasms: definition, importance, and visualization on CT colonography.
abstract: OBJECTIVE
  We discuss the definition of flat colorectal neoplasms, their clinical importance, CT colonography (CTC) findings, techniques for better visualization on CTC, and diagnostic pitfalls of such lesions.
  
  
  CONCLUSIONS
  Flat lesions appear on CTC as plaque-shaped mucosal elevations with or without a central depression, thickened haustral folds, and nodular mucosal surfaces. The sensitivity and optimal techniques of CTC for the detection of flat lesions have not yet been established. Three-dimensional endoluminal fly-through may be helpful for lesion detection. Fecal tagging helps in the distinction of true flat lesions from feces. I.v. contrast enhancement and the review with intermediate soft-tissue window settings, although not routinely used for CTC, may also help lesion visualization.
authors: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Pungnap-2dong, Songpa-gu, 138-736, Seoul, Korea. seongho@amc.seoul.kr
authors: Seong Ho
authors: SH
authors: Park
authors: Seung Soo
authors: SS
authors: Lee
authors: Eugene K
authors: EK
authors: Choi
authors: So Yeon
authors: SY
authors: Kim
authors: Suk-Kyun
authors: SK
authors: Yang
authors: Jin Ho
authors: JH
authors: Kim
authors: Hyun Kwon
authors: HK
authors: Ha
mesh_terms: D000368:Aged; D023881:Colonography, Computed Tomographic; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged