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Fundamental elements for successful performance of CT colonography (virtual colonoscopy).

Park SH, Yee J, Kim SH, Kim YH - Korean J Radiol (2007 Jul-Aug)

Bottom Line: Fecal and fluid tagging may improve the diagnostic accuracy and allow for reduced bowel preparation.Polyps detected at CTC should be measured accurately and reported following the "polyp size-based" patient management system.The time-intensive nature of CTC and the limited resources for training radiologists appear to be the major barriers for implementing CTC in Korea.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Poongnap-2dong, Songpa-gu, 138-736 Seoul, Korea. seongho@amc.seoul.kr

ABSTRACT
There are many factors affecting the successful performance of CT colonography (CTC). Adequate colonic cleansing and distention, the optimal CT technique and interpretation with using the newest CTC software by a trained reader will help ensure high accuracy for lesion detection. Fecal and fluid tagging may improve the diagnostic accuracy and allow for reduced bowel preparation. Automated carbon dioxide insufflation is more efficient and may be safer for colonic distention as compared to manual room air insufflation. CT scanning should use thin collimation of < or =3 mm with a reconstruction interval of < or =1.5 mm and a low radiation dose. There is not any one correct method for the interpretation of CTC; therefore, readers should be well-versed with both the primary 3D and 2D reviews. Polyps detected at CTC should be measured accurately and reported following the "polyp size-based" patient management system. The time-intensive nature of CTC and the limited resources for training radiologists appear to be the major barriers for implementing CTC in Korea.

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A 65-year-old male with a 6-mm tubulovillous adenoma in the sigmoid colon.A. Optical colonoscopy shows a sessile polyp (arrowhead) in the sigmoid colon.B. 3D supine endoluminal view shows the corresponding polyp (arrowhead) in a well-distended segment of the sigmoid colon.C. 3D endoluminal view of the same area as figure B, with the patient in a prone position, shows the same lesion (arrowhead) obscured by suboptimal distention.
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Figure 3: A 65-year-old male with a 6-mm tubulovillous adenoma in the sigmoid colon.A. Optical colonoscopy shows a sessile polyp (arrowhead) in the sigmoid colon.B. 3D supine endoluminal view shows the corresponding polyp (arrowhead) in a well-distended segment of the sigmoid colon.C. 3D endoluminal view of the same area as figure B, with the patient in a prone position, shows the same lesion (arrowhead) obscured by suboptimal distention.

Mentions: The importance of proper colonic distention during the performance of CTC cannot be overstated. A suboptimally distended colon can obscure (Fig. 3) or mimic a lesion (Fig. 4). Even a fairly large lesion can be missed if the colon is collapsed. Automated carbon dioxide (CO2) insufflation is increasingly being used for colonic distention during CTC. Automated CO2 insufflation is reported to improve colonic distention (23) and be safer compared to manually administered room air insufflation (24). Colonic perforation associated with CTC is a rare event. Almost all the reported cases of colonic perforation during CTC have been associated with the use of manual insufflation, whereas only two cases of asymptomatic perforations and one case of symptomatic perforation, which occurred in a patient with active stenosing ileocolic Crohn's disease, have been associated with the use of automated CO2 insufflation (25-30). Although CO2 has not been clearly shown to decrease patient discomfort during the examination, the post-procedural discomfort is less with CO2 compared to room air due to the rapid absorption of CO2 through the colonic mucosa (23).


Fundamental elements for successful performance of CT colonography (virtual colonoscopy).

Park SH, Yee J, Kim SH, Kim YH - Korean J Radiol (2007 Jul-Aug)

A 65-year-old male with a 6-mm tubulovillous adenoma in the sigmoid colon.A. Optical colonoscopy shows a sessile polyp (arrowhead) in the sigmoid colon.B. 3D supine endoluminal view shows the corresponding polyp (arrowhead) in a well-distended segment of the sigmoid colon.C. 3D endoluminal view of the same area as figure B, with the patient in a prone position, shows the same lesion (arrowhead) obscured by suboptimal distention.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2627155&req=5

Figure 3: A 65-year-old male with a 6-mm tubulovillous adenoma in the sigmoid colon.A. Optical colonoscopy shows a sessile polyp (arrowhead) in the sigmoid colon.B. 3D supine endoluminal view shows the corresponding polyp (arrowhead) in a well-distended segment of the sigmoid colon.C. 3D endoluminal view of the same area as figure B, with the patient in a prone position, shows the same lesion (arrowhead) obscured by suboptimal distention.
Mentions: The importance of proper colonic distention during the performance of CTC cannot be overstated. A suboptimally distended colon can obscure (Fig. 3) or mimic a lesion (Fig. 4). Even a fairly large lesion can be missed if the colon is collapsed. Automated carbon dioxide (CO2) insufflation is increasingly being used for colonic distention during CTC. Automated CO2 insufflation is reported to improve colonic distention (23) and be safer compared to manually administered room air insufflation (24). Colonic perforation associated with CTC is a rare event. Almost all the reported cases of colonic perforation during CTC have been associated with the use of manual insufflation, whereas only two cases of asymptomatic perforations and one case of symptomatic perforation, which occurred in a patient with active stenosing ileocolic Crohn's disease, have been associated with the use of automated CO2 insufflation (25-30). Although CO2 has not been clearly shown to decrease patient discomfort during the examination, the post-procedural discomfort is less with CO2 compared to room air due to the rapid absorption of CO2 through the colonic mucosa (23).

Bottom Line: Fecal and fluid tagging may improve the diagnostic accuracy and allow for reduced bowel preparation.Polyps detected at CTC should be measured accurately and reported following the "polyp size-based" patient management system.The time-intensive nature of CTC and the limited resources for training radiologists appear to be the major barriers for implementing CTC in Korea.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Poongnap-2dong, Songpa-gu, 138-736 Seoul, Korea. seongho@amc.seoul.kr

ABSTRACT
There are many factors affecting the successful performance of CT colonography (CTC). Adequate colonic cleansing and distention, the optimal CT technique and interpretation with using the newest CTC software by a trained reader will help ensure high accuracy for lesion detection. Fecal and fluid tagging may improve the diagnostic accuracy and allow for reduced bowel preparation. Automated carbon dioxide insufflation is more efficient and may be safer for colonic distention as compared to manual room air insufflation. CT scanning should use thin collimation of < or =3 mm with a reconstruction interval of < or =1.5 mm and a low radiation dose. There is not any one correct method for the interpretation of CTC; therefore, readers should be well-versed with both the primary 3D and 2D reviews. Polyps detected at CTC should be measured accurately and reported following the "polyp size-based" patient management system. The time-intensive nature of CTC and the limited resources for training radiologists appear to be the major barriers for implementing CTC in Korea.

Show MeSH
Related in: MedlinePlus