Evolution of gastrointestinal double contrast radiography in China: researches, application and popularization

Figure 2 Model DC. The larger round images are protrusions and the smaller ones are depressions. They are all located on Ad wall in A and in Ab wall in B. Note the difference in protrusion (blurring in outer) and in depression (blurring in inner); and the difference of the same lesion in Ad wall (A) or in Ab wall in B.