Validation by magnetic resonance imaging of tympanometry for diagnosing middle ear effusion

This study was performed to correlate tympanometric gradient with measurements of effusion quantity by use of MRI during an experimental otitis media with effusion episode in 4 cynomolgus monkeys. Paired results for the intensity values of the T(2)-weighted MRI scans and the tympanometric width measured in the right ear of all animals before and on days 15, 21, 29, and 36 after botulinum paralysis of the tensor veli palatini muscle were analyzed. All right ears showed a progressive increase during the study period in the signal intensity of the MRI. Whereas the average middle ear pressures decreased, the average tympanometric widths demonstrated a progressive increase during the course of the experimental otitis media with effusion. Significant correlations between tympanometric width and MRI measures of effusion were documented, confirming the high predictive value of the tympanometric width for diagnosing the presence and quantity of middle ear effusion.