RESULTS
Three GPA and one EGPA were included in this study (Table 1). Case 1 and Case 2had recurrenceof acute SNHL with external otitis of the posterior canal wall during an attempted taper of prednisolone (Fig. S1). Case 3 and Case 4 presented with persistent otitis media with aseptic discharge and gradual progressive SNHL as an initial symptom (Fig. S1). Bilateral ears were affected at the initial onset in Case 4. Vertigo with a complete canal paresis was seen only in Case 3.Simultaneous facial paresis was absent in all patients.
The signal intensity of each segment of the facial nerve was assessed in five affected ears (Table 2). The geniculate ganglion was normally enhanced with a moderate to intense signal intensity withoutan obvious difference between affected and unaffected ears (Fig. 1A). In all affected ears, the temporal and mastoid segments were significantly enhanced(Fig. 1B, 1C, 1D, 2A, 2B). The enhancement was detected along the course of the Fallopian canal on MIP images,and closely associated with inflammation inthe promontory, mastoid, and eustachian tube (Fig. 2C, 2D). After immunosuppressive therapy,the enhancement was attenuated to a level similar to that of unaffected ears (Fig. 1E), with a mean signal intensity score of the mastoid segment from 2.7 at onset to 1.4 inremission. On the other hand, the cisternal, canalicular, and labyrinthine segments were faintly enhanced and hardly detectable(Fig. 1A). Pachymeningitis or other intracranial involvements were not found.