In order to find out whether it is possible to visualize experimental
endolymphatic hydrops in the cochlea with magnetic resonance imaging (MRI) at 4.7 T, we used 11 guinea pigs. Five normal guinea pigs were used as controls. Early manifestation of
endolymphatic hydrops was evaluated in endolymphatic sac (ES)-intact animals (n = 6), and advanced manifestation in ES-damaged animals (n = 5) by means of MRI with
gadolinium-diethylenetriaminepentaacetate-bismethylamide (
Gd-DTPA-BMA)
contrast agent. Hearing was tested with electrocochleography. The surface area of 3 partitions of the cochlea was used to quantify
endolymphatic hydrops. The fine structure of the 3 partitions of the cochlea was visualized with MRI in all animals, as
Gd-DTPA-BMA appeared mainly in the scala tympani and scala vestibuli. As early as 5 days after endolymphatic sac surgery,
endolymphatic hydrops started to appear as visualized by MRI and also verified with histology. Severe damage to the inner ear barrier with
Gd-DTPA-BMA leakage into the scala media was detected with MRI in 1 ES-damaged animal that had a 60-dB
hearing loss. To conclude,
endolymphatic hydrops can be visualized with high-resolution MRI by means of
Gd-DTPA-BMA, and it is possible to quantify the extent of
endolymphatic hydrops. Damage to the inner ear barrier or possible
rupture of membranes can be shown with the assistance of
Gd-DTPA-BMA.