[Application of CT colonography in diagnosis of colonic polyps].

Objective: To assess the clinical values of CT colonography (CTC) in the diagnosis of colonic polyps.

Methods: Forty-two patients who were clinically suspicious of colonic polyps or underwent colonic polyps screening received both CTC and conventional colonoscopy. Sixteen or 64-slice spiral CT and professional imaging processing techniques were used for evaluation. Per-polyp and per-patient results were analyzed. Those by per-polyp were subsequently divided into > or = 10 mm group, 5-10 mm group, and < or = 5 mm group. Sensitivity, positive predictive value (PPV), specificity, negative predictive value (NPV), and accuracy were calculated using statistical method for diagnostic studies, with conventional colonoscopy as a gold standard.

Results: Ninety and 61 polyps were found by CTC and conventional colonoscopy, respectively. Sensitivity and PPV were 80.3%/55.6% by per-polyp and 100%/92.9%, 93.8%/65.2%, and 68.8%/ 41.5% in the > or = 10 mm group, 5-10 mm group, and < or = 5 mm group, respectively. Sensitivity, PPV, specificity, NPV, and accuracy by per-patient were 97.1%, 89.5%, 42.9%, 75.0%, and 88.1%, respectively.

Conclusion: CTC can clearly reveal the morphology of colonic polyps and can be used as a routine monitoring method for the clinical diagnosis of polyps.