Abstract：Objective: To access the ability and the optimal gas pressure of 16-MDCT virtual endoscopy in detection of simulated polyps with different sizes in pig colon. Methods: Twenty-four pieces of 40cm-long colon were divided into 3 groups randomly with the gas pressure of 37.5, 52.5 and 67.5mmHg. Each piece of colon had 5 simulated polyps with the size 1～2mm, 3～4mm, 5～6mm, 7～8mm and 9～10mm. All the pieces of colon underwent CT scanning with the angle of 0°, 45° and 90° to the gantry. Results: There was no significant difference for MDCT in detection of the polyps under different pressures and with different angles. Their sensitivities were all 100% except for the 1～2mm polyps detected under 37.5mmHg with the sensitivity of 75%. The depths of the colonic haustra were different under the above pressures, but there was no difference between 52.5mmHg and 67.5mmHg. Conclusion: The sensitivity of 16-MDCT virtual endoscopy in detection of polyps with the size ranged from 1 to 10mm is high. The optimal gas pressure is 52.5mmHg and it should be kept until the scanning is finished.
2007, Vol. 18 
