Characteristics of magnetic resonance imaging findings in 32 dogs diagnosed with meningoencephalitis of unknown etiology

Abstract

The purpose of this retrospective study was to describe the characteristics of magnetic resonance imaging (MRI) findings in dogs with meningoencephalitis of unknown etiology (MUE), and to evaluate the usefulness of meningeal enhancement. Thirty-two dogs were included in MUE group on the basis of clinical signs, MRI findings and cerebrospinal fluid (CSF) results, and for comparison of the meningeal enhancement, twenty-three dogs with normal MRI, normal CSF and no clinical sign were included in the control group. The evaluated MRI findings included lesion site, lesion number, signal intensity of each MRI sequence, mass effect, perilesional edema, contrast enhancement, and meningeal enhancement. The MUE was most frequently associated with multiple lesions (50%) with perilesional edema (72%) in forebrain (66%) that were hyperintense (92%) in T2W and FLAIR images. Of the meningeal enhancement, there was no significant difference between the control group and the MUE groups in the pachymeningeal enhancement. However, leptomeningeal (or both) enhancement was found relatively high proportion in the MUE group than in the control group (P < 0.001, Odd ratio = 10.26), and based on this result, leptomeningeal (or both) enhancement is considered to be significant finding for indicating MUE. ? 2020, Korean Society of Veterinary Clinics. All rights reserved.