[The roentgen diagnosis of chronic inflammatory disease of the middle ear with tomography (author's transl)].

Tomography of the middle ear is a reliable method for the diagnosis of a cholesteatoma. Radiological diagnosis is possible in nearly all cases showing changes in the bony margins of the tympanic cavity and of the retro-tympanic spaces. Bone changes of the medial wall of the tympanic cavity, unless they extend into the labyrinth, can only be shown by tomography. In contrast to cholesteatomas, osteolytic changes are rare and only superficial as a result of ordinary, chronic otitis media. They can be demonstrated by tomography, particularly in the region of the lateral wall of the attic. Diffuse enlargement of the epitympanic recess is rare in chronic otitis media. Destruction of the ossicles may be found with cholesteatomas and, more rarely, with chronic otitis media; evidence of destruction of the ossicles is therefore not adequate for a radiological diagnosis of a cholesteatoma. In addition, the demonstration of bone changes is necessary for this diagnosis. In general, the tomographic investigation of the ossicles is subject to certain limitations. In most cases, destruction of ossicles can be inferred only if their size is reduced, their shape is altered, or if they appear to be absent. Unsharpness of normal-sized or only slightly reduced ossicles is an unreliable sign and has causes other than superficial destruction. An impression of unsharp and "washed out" contours may be due to inflammtory osteoporosis of the ossicles, or to a reduced absorption differential between porotic bone and abnormal contents of the tympanic cavity. This process may even produce the appearance of absence of the ossicles. In the presence of cholesteatomas, the unsharpness is more probably due to superficial destruction than is the case with chronic otitis without a complicating cholesteatoma.