HRCT findings for tuberculous otomastoiditis and nontuberculous otomastoiditis
| CT findings | TOM (n = 19) | COM (n = 30) | CHOM (n = 30) |
|---|---|---|---|
| Soft tissue location | |||
| Mastoid antrum | 19 (100%) | 29 (97%) | 26 (87%) |
| Middle ear cavity | |||
| Entire middle ear cavity | 18 (95%) | 7 (23%)* | 12 (40%)* |
| Epitympanum | 19 | 28 | 25 |
| Mesotympanum | 18 | 11 | 12 |
| Hypotympanum | 19 | 11 | 12 |
| Preservation of mastoid air cells without sclerotic change | 14 (74%) | 4 (13%)* | 3 (10%)* |
| Soft tissue extension to the EAC or mucosal thickening of EAC | 12 (63%) | 0* | 5 (17%)* |
| Erosion of ossicles | 6 (32%) | 12 (40%) | 26 (87%)* |
| Malleus | 2 | 4 | 26 |
| Incus | 6 | 11 | 25 |
| Stapes | 3 | 5 | 14 |
| Erosion of scutum | 0 | 3 (10%) | 15 (50%)* |
| Erosion of bony labyrinth | 1 | 0 | 2 |
| Erosion of facial nerve canal | 0 | 0 | 3 |
| Erosion of tegmen tympani | 1 | 2 | 2 |
Note:— TOM indicates tuberculous otomastoiditis; COM, chronic otomastoiditis; CHOM, chronic otomastoiditis with cholesteatoma; EAC, external auditory canal.
* Statistically significant compared with tuberculous otomastoiditis by χ 2 test (P < .05).