As multi-slice CT develops, there are great expectations for an automatic and computer-support diagnoses. This
research is on bronchial area which is composed of the bronchial wall regions and the air regions in the internal bronchial
tube. Since to diagnose this is difficult, support diagnosis using CT images is desired. The thickness of bronchial wall
changes as the airway of early lung cancer, bronchial asthma and the bronchial enhancing syndrome and others change
into a malignant state. These changes are detected and the thickness of bronchial wall becomes important information. In
this research, the extraction accuracy of the algorithm for bronchial wall evaluation is good.