Abstract
In 4 cases of typical blue ear drum, CT examination was performed before and after treatment of the disease. Comparison of the CT image with that of OME (otitis media with effusion) cases demonstrated the follwoing. (1) In blue ear drum cases, an irregular mass with soft tissue density exists in the middle ear after the elimination of effusion. This distinguishes the disease from OME and demonstrated that the two can be distinctly differentiated by CT findings. (2) In blue ear drum cases, the mass having the density of soft tissue disappeared when the patients became free from symptoms. (3) The mass with soft tissue density in the middle ear cavity of blue ear drum varied in location from case to case seemed to represent cholesterol granuloma.