CT colonography using 16-MDCT in the evaluation of colorectal cancer.
OBJECTIVE
This study evaluated CT colonography as a method to stage colorectal cancer and detect polyps and cancers in patients with the disease.


METHODS
Fifty-one consecutive patients thought to have colorectal cancer underwent CT colonography, following a colonoscopy, in both the prone and supine positions. The transverse CT images, multiplanar reconstruction, volume rendered, and virtual colonoscopy images, were independently interpreted by two radiologists. Disagreements were resolved by consensus. The diagnostic accuracy of TNM staging was calculated, and the sensitivity of CT colonography for the detection of cancers and polyps, compared with that of colonoscopy, was calculated using repeated colonoscopic and surgical findings as reference standards. The technical result for distention was also graded.


RESULTS
In the 51 patients, surgery and follow-up colonoscopy revealed 21 colorectal cancers (one synchronous cancer) and 41 polyps. The diagnostic accuracies of CT colonography for TNM staging were 95%, 85%, and 100% for tumor, node, and metastasis, respectively. The sensitivity of both CT colonography and initial colonoscopy for cancer detection was 100%. The overall sensitivities of CT colonography and initial colonoscopy for polyp detection were 90% and 78%, respectively (p = 0.001). The sensitivities of CT colonography for detecting polyps of 5 mm or smaller, of 6-9 mm, and of 10 mm or larger were 84%, 94%, and 100%, respectively. The mean overall technical results for the supine and prone positions were ranked as 2.80 (SD, +/- 0.4) and 2.78 (+/- 0.4), respectively, but were without statistical significance (p = 0.781).


CONCLUSIONS
Our preliminary data suggest that for patients with clinical suspicion of colorectal cancer, CT colonoscopy is valuable in staging the tumor and in detecting additional polyps or cancers in areas not evaluated by conventional colonoscopy.
Chung
Dong Jin
DJ
Department of Radiology, University of Konyang School of Medicine, 685 Gasuwon-dong, Seo-gu, Daejeon 302-718, Korea. bookdoo7@chollian.net
Chung
Don Jin
DJ
Huh
Kyu Chan
KC
Choi
Won Jun
WJ
Kim
Jae Kyun
JK
D000328:Adult; D000368:Aged; D003111:Colonic Polyps / Q000000981:diagnostic imaging; D023881:Colonography, Computed Tomographic / Q000379:methods*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies; D018709:Statistics, Nonparametric