Fusing MRI and CBCT: Muscle atrophy as key to explaining eustachian tube dysfunction?

This study aimed to investigate the correlation between Eustachian tube (ET) dimensions and Eustachian tube dysfunction (ETD).

A total of 28 patients with ETD symptoms ≥ three months and ten controls underwent 3 Tesla magnetic resonance imaging (MRI) and Cone beam computed tomography (CBCT) scans. The images were fused with software using anatomical landmarks. ET dimensions and angles were registered.

Patient and control demographics were comparable. The length of ET was longer in ETD ears compared to controls (p = 0.035) but not compared to the ETD patient's asymptomatic ears (p > 0.05). ET length was longer in males compared to females in the ETD group (p < 0.001). The osseous ET was longer in the patients' ETD ears compared to their asymptomatic ears. Cartilaginous ET was shorter in controls compared to ETD ears. No significant length differences (p > 0.05) were observed between sides in ET, CET, or OET. A positive correlation was found between ET length and height (p < 0.001). No significant differences in angles were found between ETD ears, asymptomatic ears, or controls against either the horizontal or the sagittal plane.

Fusion of MRI and CBCT is feasible for evaluating ET. Adjusting for height, no differences in ET length between sexes were found. OET was longer in symptomatic ears, and CET was shorter in controls. ETD seems associated with a longer ET. Ostmann's Fat Pad and the levator veli palatini muscle were smaller in ETD ears, suggesting atrophy of ET components.