The diagnostic yield of advanced imaging in dogs with Horner's syndrome presenting with and without additional clinical signs: A retrospective study of 120 cases (2000-2018).

This is the first study to evaluate the diagnostic yield of advanced imaging in dogs with HS. Isolated HS is significantly more likely to be idiopathic than cases presenting with additional clinical signs; this could guide decision-making regarding further investigations performed in a clinical setting. Idiopathic HS is over-represented in the golden retriever.