[A study on the fine mucosal pattern in the duodenal bulb].

To estimate the smallest unit of mucosa in the duodenal bulb radiologically, double contrast radiographs were investigated in correlation with endoscopy and histological examinations of biopsy specimens. Fine mucosal structures in the duodenal bulb were observed in 692 out of 1463 cases (47.4%) in double contrast radiographs in our upper gastrointestinal series from January, 1989 to December, 1990. Fine mucosal structures were subdivided into 3 categories: A; reticular and/or granular pattern (60.1%, 416/692), B; diffuse nodular pattern with or without additional A pattern (35.3%, 244/692), and C; diffuse tiny barium dots (4.6%, 32/692). Three pattern groups were reviewed by endoscopic and histological assessment of biopsy specimens in comparison with the control group of nonvisualized mucosal pattern (30 cases). Endoscopic observation was carried out in 170 out of 692 radiology cases in respect to irregularities in the duodenal mucosa (villous pattern, mucosal colour, nodule or depression, or disease) and associated diseases of the stomach. Fewer diseases (1 ulcer scar and 7 cases of the duodenitis, 15.6%) were visualized in the duodenal bulb than the stomach due to a prominent acid secretive function, which was confirmed by the Congo-Red method in groups A and B. A flat villi pattern was noted with accompanying disease in the duodenal bulb in 8 out of 11 cases of in group C (72.7%). By the Whitehead classification of duodenitis, 100% of group A, 98.5% of group B and 100% of group C revealed low grade inflammation (Grade < 2) in histological examinations of biopsy specimens (120 cases). The nodule seen in B pattern was histologically composed of nonspecific protruded mucosa (38%, 19/50), proliferation of lymphoid follicle (36%, 18/50), Brunner's gland hyperplasia (24%, 12/50) or heterotopic gastric mucosa (2%, 1/50). Consequently, mucosal patterns A, B and part of C might be appropriate as basic mucosal units of the normal duodenal bulb in double contrast radiograph.