Detection of colorectal polyps by multislice CT colonography with ultra-low-dose technique: comparison with high-resolution videocolonoscopy.
BACKGROUND
This prospective study compared multislice CT colonography with ultra-low-dose technique to high-resolution videocolonoscopy as the standard for detection of colorectal cancer and polyps.


METHODS
After standard bowel preparation, 115 patients underwent multislice CT colonography with an ultra-low-dose multislice CT colonography protocol immediately before videocolonoscopy. After noise reduction by using a mathematical algorithm, ultra-low-dose multislice CT colonographic images were analyzed in blinded fashion, and the results were compared with the results of high-resolution videocolonoscopy.


RESULTS
A total of 150 lesions were detected by high-resolution videocolonoscopy in 115 patients. For ultra-low-dose multislice CT colonography, sensitivities for detection of polyps less than 5 mm in size, 5 to 10 mm, and greater than 10 mm in diameter were 76%, 91%, and 100%, respectively. Although the sensitivity for detection of flat lesions was only 50%, the sensitivity and the specificity for detection of polyps 5 mm or greater in size were 94% and 84%, respectively. For adenomatous lesions greater than 5 mm in size, sensitivity was 94% and specificity was 92%. The overall specificity was 79%. The calculated effective radiation dose ranged between 0.75 and 1.25 mSv.


CONCLUSIONS
Compared with high-resolution videocolonoscopy, ultra-low-dose multislice CT colonography has excellent sensitivity and specificity for detection of colorectal lesions 5 mm or greater in size, and the radiation exposure is relatively low. However, before this technique can be generally recommended for colorectal screening, further improvement in the detection of flat and extremely small lesions must be achieved.
Division of Medicine, Department of Gastroenterology, Hepatology and Infectious Diseases, Institute of Diagnostic Radiology, Heinrich-Heine-University of Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
Christoph
C
Vogt
Mathias
M
Cohnen
Andreas
A
Beck
Stephan
S
vom Dahl
Volker
V
Aurich
Ulrich
U
Mödder
Dieter
D
Häussinger
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003113:Colonoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D007417:Intestinal Polyps / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012002:Rectal Diseases / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D020535:Video-Assisted Surgery