This study was performed to correlate tympanometric gradient with measureme
nts of effusion quantity by use of MRI during an experimental otitis media
with effusion episode in 4 cynomolgus monkeys. Paired results for the inten
sity values of the T-2-weighted MRI scans and the tympanometric width measu
red in the right ear of all animals before and on days 15, 21, 29, and 36 a
fter 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 decr
eased, the average tympanometric widths demonstrated a progressive increase
during the course of the experimental otitis media with effusion. Signific
ant correlations between tympanometric width and MRI measures of effusion w
ere documented, confirming the high predictive value of the tympanometric w
idth for diagnosing the presence and quantity of middle ear effusion.