Three-Dimensional-CT Imaging of Colorectal Disease with Thin Collimation Helical CT Scanning Toshihiro Ogura 1 , Koichi Koizumi 2 , Tatsuya Sakai 2 , Kazuaki Takatsu 1 , Masakazu Maruyama 2 1Department of Radiology, Cancer Institute Hospital 2Department of Internal Medicine, Cancer Institute Hospital Keyword: 大腸内視鏡 , 大腸癌 , ヘリカルスキャンCT , 三次元CT pp.187-196
Published Date 1998/2/25
DOI https://doi.org/10.11477/mf.1403103576
  • Abstract
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 We have conducted research on three-dimensional (3D)-CT-colonoscopy with thin collimation helical CT scanning over the past three years. This has lately become a subject of special interest. 3D-CT-colonoscopy has three kinds of visualizing methods depending on the threshold setting of CT values. The first one is the virtual endoscopy method which is displayed in a similar fashion to colonoscopic images. The second one is the air image method using the air in the digestive tract as a contrast medium. The third one is the pseudo-tract method which has characteristics of both virtual endoscopy and the air image method and visualizes in a shape of the digestive tract. The image visualized by 3D-CT-colonoscopy is similar to that of conventional colonoscopy and barium enema study, which is obtained with minimal invasion to patients. Obvious advanced carcinomas were easily visualized, and even a small flat polyp measuring 5 mm in size, was able to be observed retrospectively. The characteristics of our method are that we can easily make an examination in a short time and with little dependence on expert technique. Also patients have little discomfort compared to that experienced during colonoscopy and barium enema study. Important features are as follows; 1) long calculation time, 2) insufficient air insufflation, 3) fecal material in the patient's bowel, 4) whole abdominal scan, 5) spatial resolution. In the near future, a multislice CT scanner system will have ability to overcome these problems. Therefore, 3D-CT-colonoscopy might be applied in the future for first line examination as a mass screening for colorectal carcinoma.

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