Purpose <p>The diagnosis of eosinophilic otitis media (EOM) remains a major challenge. Current diagnostic methods rely primarily on accurate samples of middle ear tissue or secretions, which can be complex. In this study, we sought to explore the diagnostic value of mastoid pneumatization combined with other temporal radiological features for EOM.</p> Methods <p>This study included 28 patients with EOM and 32 patients with ordinary OM. All participants underwent the temporal bone HRCT, and middle ear status was assessed using four sections: mesotympanum, attic, antrum, and mastoid air cells. Quantification of negative temporal bone pressure using three-dimensional analysis of mastoid volume images.</p> Results <p>The volumes of eosinophilic/non-eosinophilic mastoid air cells were approximately the same but were asymmetric. In contrast, in the normal OM group, there was a significant difference in the volume of mastoid air cells between the inflammatory and non-inflammatory sides. Statistically, the degree of opacification to the mesotympanum, attic, and mastoid air cells was more severe in patients with EOM than in patients with ordinary OM on the affected side. Furthermore, on the normal side, the opacification of the all four sites in the eosinophil group was basically worse than that in the control group.</p> Conclusion <p>Eosinophilic individuals have been found to be specific to the mastoid air cell system and middle ear status and are important factors to consider. Therefore, the potential imaging information of HRCT can help otologists diagnose EOM earlier and provide timely and effective treatment.</p>