Experimental study of tagged fluid in CT virtual colonoscopy / 第三军医大学学报

ABSTRACT

Objective To investigate the effects of tagged fluid and substraction in CT virtual colonoscopy (CTVC) on the conspicuity of polyps and to confirm the optimal attenuation value and the optimal viewing window. Methods Polyps measured 3-10 mm were created in fresh porcine colon in vitro and submerged in saline and mixed with positive contrast medium for the CT values of 200 HU, 400 Hu, 600 HU, and 800 HU. Polyps were measured before and after substraction and compared with those in the control group. The effects of different viewing windows and different attenuation values on the measurement and conspicuity of polyps were analyzed. Results The optimal attenuation value of tagged fluid was 800 HU and the optimal viewing window was colon (-150 HU, 1 500 HU) and bone (500 HU, 2 500 HU). Conclusion The combination of tagged fluid and CT substraction can improve the conspicuity of small polyps covered by colonic fluid.