Detection of colorectal polyps by computed tomographic colography: feasibility of a novel technique.
OBJECTIVE
Computed tomographic colography (CTC) represents a novel technique for colorectal polyp detection. A prospective study was undertaken to determine the optimal CTC scanning parameters based on an artificial colon model and to assess the feasibility of CTC to detect clinically significant colorectal polyps.


METHODS
A colon model was scanned by helical computed tomography at multiple parameters. Reformatted two-dimensional and three-dimensional images were then graded for polyp detection and image quality. Subsequently, 10 patients with known colon polyps underwent CTC immediately before colonoscopy. The number of polyps detected by two radiologists using CTC were compared with colonoscopy results that served as the gold standard.


RESULTS
The optimal scanning parameters in the colon model were 5-mm collimation, 5 mm/s table speed, and 1-mm reconstruction interval. Ten patients had 30 polyps (range, 0.2-2.0 cm) by colonscopy, and all polyps > or = 0.5 cm were adenomas. Polyp detection by CTC for both observers was 100% (5 of 5) > or = 1 cm, 71% (5 of 7) between 0.5 and 0.9 cm, and 11%-28% (2-5 of 18) < 0.5 cm.


CONCLUSIONS
Based on this small, unblinded pilot study, CTC is feasible for colorectal polyp detection > or = 0.5 cm in diameter.
Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota, USA.
A K
AK
Hara
C D
CD
Johnson
J E
JE
Reed
D A
DA
Ahlquist
H
H
Nelson
R L
RL
Ehman
C H
CH
McCollough
D M
DM
Ilstrup
D000368:Aged; D000369:Aged, 80 and over; D003111:Colonic Polyps / Q000000981:diagnostic imaging* / Q000473:pathology; D003113:Colonoscopy; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011127:Polyps / Q000000981:diagnostic imaging* / Q000473:pathology; D011446:Prospective Studies; D012002:Rectal Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed