Imaging of Endolymphatic and Perilymphatic Fluid at 3T After Intratympanic Administration of Gadolinium-Diethylene-Triamine Pentaacetic Acid

A 46-year-old man with Ménière disease. All images were obtained 24 hours after the intratympanic injection of Gd-DTPA. A, Perilymphatic fluid image obtained with 3D-FLAIR (9000/128/2500). Low signal intensity areas (arrows) can be recognized as enlarged endolymphatic space in the cochlea. Note that the vestibule and posterior semicircular canal (short arrows) also showed low signal intensity, so we could not determine whether the vestibule and posterior semicircular canal were filled with endolymphatic fluid. B, Endolymphatic fluid image obtained with a 3D inversion-recovery sequence (9000/128/1000). Endolymphatic space in the cochlea (arrows) shows high signal intensity on this image. This image confirmed that the vestibule and posterior semicircular canal were filled with fluid. C–G, Fusion of a perilymphatic fluid image (C) and an endolymphatic fluid image (G) with transitional images (D–F). By changing the fusion mixture rate on a workstation, the spatial relationship between perilymphatic and endolymphatic space was easily appreciated in both the cochlea and vestibule. In this case, endolymphatic space was enlarged in both the cochlea and vestibule, but the enlargement was especially prominent in the vestibule. Note that CSF in the internal auditory canal is visualized as high signal intensity on the endolymphatic fluid image (G). The signal intensity of perilymphatic space is just suppressed. Thus, the term endolymphatic image is only useful for labyrinthine space.