Virtual colonoscopy: Technical guide to avoid traps and pitfalls

Abstract

The study aims to clarify the ideal technique of virtual colonoscopy and how to avoid pitfalls. Patient and methods200 patients were referred for VC screening. Results3D 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 navigationThere 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. ConclusionMany overestimating or underestimating VC pitfalls could be avoided, through mastering the technique and being more familiar with different navigation methods and these technical pitfalls.