Virtual colonoscopy: Technical

Abstract

The study aims to clarify the ideal technique of virtual colonoscopy and how to avoid pitfalls. Patient and methods: 200 patients were referred for VC screening. Results: 3D VC false positive results were as follows: Pseudopolyps due to fecal residue (17.5%), under-distended colon (2%), segmental spasm (1%), respiratory motion artifacts (3%), prominent colonic haustrations (8.5%), prominent ileocecal valve (4.5%), prominent appendicular stump (0.5%) and false pits due to shine-through (1.5%). 3D false negative results were proved secondary to fecal residue (1.5%), retained fluid (2.5%), colonic under-distention (5%), prominent colonic folds (1%) and sessile polyps (1%). 2D navigation: There were no false positive results. 3.5% false negative results were due to different combinations of fecal residue (3%), fluid (2%), under-distended colon (1%), prominent colonic haustrations (2.5%) and sessile polyps (1%). Finally, true positive results were proven in 40% of 3D and 47.5% of 2D navigations, true negative: 29.5% in 3D and 49% 2D. False positive results were proven in 19.5% of 3D, false negative results: 11% 3D and 3.5% 2D. 3D 78.4%, 2D 93% sensitivity and 3D 60.2% & 2D 100% specificity records. Conclusion: Many overestimating or underestimating VC pitfalls could be avoided, through mastering the technique and being more familiar with different navigation methods and these technical pitfalls.

Keywords

• Virtual colonoscopy
• High risk patients
• Polypspsuedolesions
• 2D navigation
• 3D navigation