Measuring Thickness of Middle Ear Mucosa Using MRI and CT Imaging versus Histopathology

Objective. Otitis media (OM) is characterized by increased middle ear effusion and inflammation of middle ear tissue. In this study, we compared two radiographic methods of analyzing inflammation by measuring mucosal thickness (MT). Methods. 28 chinchillas were divided into three treatment groups consisting of a vehicle control group and two glucocorticoid groups. 6 underwent treatment by vehicle control, 10 were treated with ciprofloxacin 0.3%/dexamethasone 0.1% (DEX), and 10 received ciprofloxacin 0.2%/hydrocortisone 1% (HC). 96 hrs post-LPS inoculation, chinchillas were euthanized and their temporal bones were removed for analyses. Results. MRI scans (F = 146.0861, P-value <0.0001) and histology (χ (2) = 40.5267, P-value <0.0001) revealed statistically significant differences in MT measurements among treatment groups, whereas CT imaging did not. DEX-treated chinchillas exhibited overall significantly smaller MT values. Conclusion. Imaging MT was effective for determining severity of inflammation due to OM. Previous gold standard methods using histopathology compromise tissue integrity by chemical manipulation and dehydration effects. MRI and CT scanning are viable tools to preserve tissue and examine changes in MT. In this study, MRI provided more information about internal, soft tissue structures. In a clinical setting, MRI could be used for diagnosing and tracking severe or chronic OM.