Magnetic resonance imaging findings in dogs presenting with paroxysmal dyskinesia and a normal neurological examination

Introduction Paroxysmal dyskinesia (PD) is a subtype of movement disorder commonly reported in dogs. Paroxysmal dyskinesia is diagnosed based on the nature of the episodes, including preserved consciousness and an absence of autonomic signs. Methods In this retrospective study, the medical records of dogs presenting with at least two PD episodes occurring more than 24 h apart were reviewed. Inclusion criteria were a normal inter-ictal neurological examination, brain MRI, and exclusion of metabolic or toxic causes. Results One hundred and four dogs were diagnosed with PD. Thirty-five cases of 104 (33.7%) had abnormalities on MRI; 34/35 (97.2%) of these were classified as incidental findings. One patient (female neutered 9-year-old mixed breed) had a structurally significant finding of localized meningeal thickening with abnormal enhancement adjacent to the cerebellum, falx cerebri, and left occipital cortex. Discussion Dogs with a history of PD and a normal neurological examination exhibit a very low frequency (1.0%) of structurally significant MRI abnormalities, supporting a selective approach to advanced imaging. A larger study may help identify risk factors for structurally significant MRI abnormalities.