| [ Summary ] |
In the implementation of endoscopic ultrasonography (EUS), it is important to analyze the ultrasonic layer-structure of the colonic wall, for the diagnosis of colorectal diseases. It proposes that the normal colonic wall is ordinarily illustrated as a 5 to 7 layer-structure, using 7.5MHz frequency transducers. Recently EUS, using 20MHz high-frequency transducers, has been applied in clinical cases. An ultrasonic probe (UM-3R ; 20MHz, Olympus Optical Co.) and an ultrasonic scope(CF-UMQ200 ; 7.5 and 20MHz, Olympus Optical Co.) were used to evaluate the ultrasonic layer-structure of the colonic wall. By producing images of the resected colon with 20MHz high-frequency transducers, the ultrasonic layer-structure of the wall was demonstrated as a high resolutional ultrasonic image, consisting of 5 to 11 layers. In the case of an 11-layered structure, the 3rd layer (3a ; high echoic band) and the 4th layer (3b ; low echoic band) corresponded to the interface echo and the muscularis mucosae, the 6th layer (3d ; relatively low echoic band) to the substance echo within the submucosal layer. However,in the clinical cases, the colonic wall structure was usually divided into 9 layers. The images corresponded to the interface echo and the muscularis mucosae could not be continuously visualized, Further investigation of the layer structure, when detailed images of the muscularis mucosae and the inner-layer structures of the submucosal layer are observed, will provide more reliable information for the diagnosis of colorectal diseases. |