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 w ith vestibular disorders (VD) and correlate results of MR imaging with clin ical 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 reviewe d. Results-27 dogs had peripheral VD, 37 had central VD, and 21 had paradoxica l VD. Of the 27 dogs with peripheral VD, 11 (41%) had MR imaging abnormalit ies involving the ipsilateral tympanic bulla compatible with otitis media ( 6 also had abnormalities involving the petrous portion of the ipsilateral t emporal bone compatible with otitis interna), 7 (26%) had MR imaging abnorm alities compatible with middle ear neoplasia, 2 (7%) had an ipsi lateral ce rebellopontine angle lesion, and 7 (26%) did not have MR imaging abnormalit ies. 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 lesi on, 6 (16%) had an intra-axial lesion, and 18 (49%) had multiple intra-axia l lesions. In 23 (62%) dogs with central VD, lesions on MR images correspon ded 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 int ra-axial lesion, and 4 (19%) had multiple intra-axial lesions. Location of lesions on MR images agreed with location suspected on the basis of clinica l signs in 19 (90%) dogs. Conclusions and Clinical Relevance-Results suggest that MR imaging may be h elpful in the diagnosis and treatment of VD in dogs.