[Evaluation of computed tomographic colonography for detection of colorectal polyps].
BACKGROUND
Computed tomographic colonography has been proposed for detection of colorectal polyps instead of colonoscopy in colorectal cancer screening programs.


OBJECTIVE
To evaluate the performance of computed tomographic colonography in the detection of colorectal polyps with colonoscopy used as the gold standard.


METHODS
We prospectively studied 20 patients at high risk for colorectal neoplasia (14 men and 6 women; mean age, 55 years and 59 years). Computed tomographic colonography was performed immediately before colonoscopy. We inserted a rectal balloon catheter and insufflated the colon with room air to the level that a good distension was observed. Twenty milligrams of hioscin was given immediately before computed tomographic imaging of the abdomen and pelvis in order to minimize the degree of smooth-muscle spasm and peristalsis and to reduce the patient's discomfort.


RESULTS
Computed tomographic colonography images were considered satisfactory in all cases. Colonoscopy detected 85 polyps in 19 of 20 patients (95%). All the observed polyps were successfully removed and examined histologically. The radiological examination correctly identified 8 of 10 polyps 10 mm or more in diameter, 2 of 19 (18,2%) with 5-9 mm, and just 1 of 53 <5mm (9,1%). Seventeen of the 43 adenomatous polyps were > or =5 mm. Eight (47%) were correctly identified on computed tomographic colonography. None of the neoplasias <5 mm were identified on colonography. Nineteen patients preferred colonoscopy in the event of having to repeat on of the two examinations.


CONCLUSIONS
For the detection of colorectal polyps, computed tomographic colonography seems to be useful only when the result is positive, as the negative results of this examination cannot eliminate the presence of these lesions.
Pfeifer
Gustavo Kuhn
GK
Departamento de Ciências Morfológicas da Universidade Federal do Rio Grande do Sul, Porto Alegre, RS. gkpfeifer@via-rs.net
Corleta
Oly
O
Gus
Pedro
P
D018256:Adenomatous Polyps / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging*; D003111:Colonic Polyps / Q000145:classification / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic / Q000592:standards*; D003113:Colonoscopy / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D012680:Sensitivity and Specificity