Flat colorectal neoplasms: definition, importance, and visualization on CT colonography.
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.
Park
Seong Ho
SH
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
Lee
Seung Soo
SS
Choi
Eugene K
EK
Kim
So Yeon
SY
Yang
Suk-Kyun
SK
Kim
Jin Ho
JH
Ha
Hyun Kwon
HK
D000368:Aged; D023881:Colonography, Computed Tomographic; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged