Results of magnetic resonance imaging in dogs with vestibular disorders: 85 cases (1996-1999)

OBJECTIVE: To determine results of magnetic resonance (MR) imaging in dogs with vestibular disorders (VD) and correlate results of MR imaging with clinical findings. DESIGN: Retrospective study. ANIMALS: 85 dogs. PROCEDURE: Information on signalment, clinical signs, and presumptive lesion location was obtained from the medical records, and MR images were reviewed. RESULTS: 27 dogs had peripheral VD, 37 had central VD, and 21 had paradoxical VD. Of the 27 dogs with peripheral VD, 11 (41%) had MR imaging abnormalities involving the ipsilateral tympanic bulla compatible with otitis media (6 also had abnormalities involving the petrous portion of the ipsilateral temporal bone compatible with otitis interna), 7 (26%) had MR imaging abnormalities compatible with middle ear neoplasia, 2(7%) had an ipsilateral cerebellopontine angle lesion, and 7 (26%) did not have MR imaging abnormalities. All dogs with central and paradoxical VD had abnormalities evident on MR images. Of the 37 dogs with central VD, 13 (35%) had an extra-axial lesion, 6 (16%) had an intra-axial lesion, and 18 (49%) had multiple intra-axial lesions. In 23 (62%) dogs with central VD, lesions on MR images corresponded with location suspected on the basis of clinical signs. Of the 21 dogs with paradoxical VD, 12 (57%) had an extra-axial lesion, 5 (24%) had an intra-axial lesion, and 4 (19%) had multiple intra-axial lesions. Location of lesions on MR images agreed with location suspected on the basis of clinical signs in 19 (90%) dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that MR imaging may be helpful in the diagnosis and treatment of VD in dogs.