Diagnostic imaging of superficial type of colo-rectal cancer by X-ray and MRI

Recently the detection of superficial type (flat elevations) of colo-rectal cancer increased and the radiological appearance of these lesions were also analyzed in detail. There have been some improvements in technical approach and equipments in detecting minute colo-rectal cancer. First of all, examiners should always think about the existence of flat elevations in the large intestine. Secondly, examiners should fluoroscopically observe each segment of the intestine separately from the rectum to the terminal ileum. Thirdly, examiners should observe the barium flow across the entire mucosal surface of the segment carefully on the fluoroscopic image. We have also developed the new moving grid system: a grid for fluoroscopy (a low-ratio grid) which is fixed in front of image intensifier, and another grid for radiography (a high-ratio grid) which is fixed to the moving frame below the film cassette carriage. The surface configuration of flat elevations studied radiographically is illustrated in figures 3 and 5. These surface patterns, especially the shallow depression, are quite important for the therapeutic planning. MR imaging using an endorectal surface coil can potentially visualize the layering structures of the normal intestine as clearly as the endoscopic sonography. Intramural tumor invasion confined to the intestinal wall was best evaluated in the T2 weighted image. While, T1 weighted images were necessary to evaluate the extramural tumor invasion.