CLINICAL RELEVANCE OF MAGNETIC-RESONANCE-IMAGING AND COMPUTED-TOMOGRAPHY IN COGANS-SYNDROME

The Pathologic changes in the inner ears of 5 patients with Cogan's sy ndrome were studied by a combined application of MR imaging and CT sca nning. We used T1- and T2-weighted MR imaging sequences and a special three-dimensional MR imaging technique which allows a very detailed im aging of the inner ear structures. By the use of a CT scan simultaneou sly, calcified and noncalcified obliterations could be differentiated. The aim of the study was to visualize membranous labyrinth pathology in Cogan's syndrome and correlate them with the clinical findings. In one patient who recovered completely without hearing loss, the MR and CT investigations revealed no pathology. In the remaining 4 cases, nar rowing or obliteration of parts of the vestibular labyrinth was seen. In 3 patients, we found aberrations in the cochlea consistent with the audiological data. The gadolinium-enhanced T1-images showed enhanceme nt of the cochlea and vestibular labyrinth in one case, probably indic ating an active process with interruption of the ''blood-labyrinth bar rier''. The results are consistent with the hypothesis that the inner ear pathology in Cogan's syndrome is probably caused by obstructive va sculitis.