Results of magnetic resonance imaging performed within 48 hours after head trauma in dogs and association with outcome: 18 cases (2007–2012)

Objective—To review results of MRI performed within 48 hours after head trauma in dogs and identify associations between MRI findings and outcome. Design—Retrospective case series. Animals—18 dogs that underwent MRI within 48 hours after known head trauma. Procedures—Medical records were reviewed for information on signalment, history, clinical findings, MRI findings, treatment, and outcome. Results—2 dogs were euthanized, 1 died, and 1 had major persistent deficits. The remaining 14 dogs had a good outcome, including 9 that recovered completely and 5 that had minor persistent deficits. The most common MRI abnormalities were intra-axial changes (n = 13) and extra-axial hemorrhage (13). Intra-axial changes were best seen on T2-weighted and fluid attenuation inversion recovery (FLAIR) images. A mass effect was detected in 9 dogs, 6 of which had a midline shift (mean, 2.18 mm). Three dogs had transtentorial herniation, and 2 had transcranial herniation. Extra-axial hemorrhage was best seen on FLAIR images. The most common location was subdural, with subdural extra-axial hemorrhage most often seen on the same side as the injury. Epidural hemorrhage was seen in 2 dogs. The affected area was larger in these dogs than in dogs with subdural hemorrhage. One dog required surgery and the other was euthanized. Conclusions and Clinical Relevance—Results suggested that in dogs with acute (< 48 hours’ duration) head trauma, T2-weighted and FLAIR images provided the most diagnostic information. Dogs with injuries affecting the caudal fossa or affecting both the rostral and caudal fossae typically had poorer outcomes.