Abstract:

BACKGROUND: CT examination of gastrointestinal tract becomes possible with the widely using of multi-slice spiral CT.
OBJECTIVE: To evaluate the validity of two- and three-dimensional post processing techniques of CT colonography.
METHODS: CT colonography data by multi-slice spiral CT of 38 patients with suspicious colon disease were analyzed. Two-dimensional techniques concluded the original axial images and coronal and sagittal images obtained by multi-planar reformation (MPR). Three-dimensional techniques concluded CT virtual colonoscopy, shaded surface display, raysum and virtual pathology (luman unfolded). The location, size and appearance around colon were evaluated by two imaging physicians and compared with surgical findings and electronic colonoscope.
RESULTS AND CONCLUSION: A total of 17 polyps, 20 masses, and 5 cases of colonic inflammation were detected except one case of familial adenoma polypsis. The detection ratio of there diseases was: 82%, 100%, and 100% for MPR; 100%, 100%, and 80% for CT virtual colonoscopy; 41%, 90%, and 40% for shaded surface display; 47%, 90%, and 40% for raysum. The detection ratio for virtual pathology (luman unfolded) was 100%. Two-dimensional images are the foundation of multi-slice CT and can evaluate the position, size and density of colon disease objectively, and exhibits advantages in showing information outside the affected colon segments. The sensitivity of CT virtual colonoscopy is higher than other techniques. Virtual pathology can avoid the blind area of colon lumen. Shaded surface display and raysum have advantage on display the overall view of colon.