Computed tomographic colonography
In medicine, computed tomographic colonography, also called CT colonography and virtual colonoscopy, is a "non-invasive imaging method that uses computed tomographic data combined with specialized imaging software to examine the colon."[1]
Accuracy
According to the US Preventive Services Task Force (USPSTF), the accuracy of CT colonography is:[2] For adenomas at least 10 mm in size
- sensitivity = 92%
- specificity is uncertain and ranges from 88 to 96%
For adenomas at smaller than 10 mm in size
- sensitivity is uncertain and ranges from 65[3] to 89%
- specificity is uncertain and ranges from 80 to 88%
The positive predictive value of seeing a colonic polyp greater than 10 mm in size with CT colonoscopy and actually having such a polyp by colonoscopy is about 25%.[3]
Role in colorectal cancer prevention
A clinical practice guideline by the US Preventive Services Task Force (USPSTF) gave a grade I recommendation for CT colongraphy in screening for colorectal cancer stating "the evidence is insufficient to assess the benefits and harms of computed tomographic colonography."[2][4] The most recent study used by the systematic review for this clinical practice guideline was in 2008.[3]
A joint clinical practice guideline by the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology states that CT colonography is an acceptable option for colorectal cancer screening.[5]
A recent study proposed that any patient with a colonic polyp 5 mm or more size seen by CT colonography, should be referred for colonoscopy.[3] However, even polyps less than 5 mm may have villous histology or high-grade dysplasia.[6]
References
- ↑ Anonymous (2024), Computed tomographic colonography (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ 2.0 2.1 U.S. Preventive Services Task Force (October 2008). "Screening for Colorectal Cancer: U.S. Preventive Services Task Force Recommendation Statement". Annals of internal medicine. PMID 18838716. [e]
- ↑ 3.0 3.1 3.2 3.3 Johnson CD, Chen MH, Toledano AY, et al (September 2008). "Accuracy of CT colonography for detection of large adenomas and cancers". The New England journal of medicine 359 (12): 1207–17. DOI:10.1056/NEJMoa0800996. PMID 18799557. Research Blogging.
- ↑ Whitlock EP, Lin JS, Liles E, Beil TL, Fu R (October 2008). "Screening for Colorectal Cancer: A Targeted, Updated Systematic Review for the U.S. Preventive Services Task Force". Annals of internal medicine. PMID 18838718. [e]
- ↑ Levin B, Lieberman DA, McFarland B, et al (May 2008). "Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology". Gastroenterology 134 (5): 1570–95. DOI:10.1053/j.gastro.2008.02.002. PMID 18384785. Research Blogging.
- ↑ Butterly LF, Chase MP, Pohl H, Fiarman GS (March 2006). "Prevalence of clinically important histology in small adenomas". Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association 4 (3): 343–8. DOI:10.1016/j.cgh.2005.12.021. PMID 16527698. Research Blogging.