title: Adverse reactions following administration of contrast media for diagnostic imaging in anaesthetized dogs and cats: a retrospective study.
abstract: OBJECTIVE
  To evaluate incidences of adverse reaction after the administration of contrast media.
  
  
  METHODS
  Retrospective observational study.
  
  
  METHODS
  Animals included 356 dogs and 58 cats receiving non-ionic iodinated contrast agents, and 425 dogs and 49 cats receiving gadolinium-based contrast agents.
  
  
  METHODS
  Anaesthesia records of dogs and cats receiving intravenous (IV) gadobutrol for magnetic resonance imaging (MRI) or IV iohexol for computed tomography (CT) were reviewed. Changes in pulse rate, respiratory rate and mean arterial pressure at 5 minutes after administration of the contrast medium were evaluated. Changes of 10-20% were considered mild, those of >20% moderate, and reactions that required immediate treatment were considered severe. Associations of sex, age and weight with contrast reaction were investigated using logistic regression. Differences in the incidences of reactions to CT and MRI contrast media were examined with chi-squared tests. A p-value of <0.05 was considered to indicate statistical significance.
  
  
  RESULTS
  Of cats receiving iohexol, eight (13.8%) had mild and 10 (17.2%) had moderate reactions. Of cats receiving gadobutrol, six (12.2%) had mild and six (12.2%) had moderate reactions. No cats had severe reactions and the risk for reaction was not associated with type of medium, age, weight or sex (p > 0.2). Of dogs receiving iohexol, 64 (18.0%) had mild, 65 (18.3%) had moderate and three (0.8%) had severe reactions. Of dogs receiving gadobutrol, 42 (9.9%) had mild, 87 (20.5%) had moderate and one (0.2%) had a severe reaction. When dogs receiving iohexol were compared with those receiving gadobutrol, the odds ratio of a moderate reaction was 2.0 (95% confidence interval 1.34-3.10; p = 0.001). These estimates did not change substantially after adjustment for age, weight and sex.
  
  
  CONCLUSIONS
  Severe reactions to iohexol and gadobutrol are rare in dogs and cats; moderate reactions are more likely with iohexol than with gadobutrol.
authors.affiliation: School of Veterinary Science, Liverpool University, Liverpool, UK.
authors.forename: Stefania
authors.identifier: http://orcid.org/0000-0001-8606-4635
authors.initials: S
authors.lastname: Scarabelli
authors.affiliation: School of Veterinary Science, Liverpool University, Liverpool, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Cripps
authors.affiliation: School of Veterinary Science, Liverpool University, Liverpool, UK.
authors.forename: Eva
authors.initials: E
authors.lastname: Rioja
authors.affiliation: School of Veterinary Science, Liverpool University, Liverpool, UK.
authors.forename: Briony
authors.initials: B
authors.lastname: Alderson
mesh_terms: D000758:Anesthesia / Q000662:veterinary*; D000818:Animals; D002415:Cats; D003287:Contrast Media / Q000009:adverse effects*; D004285:Dogs; D005260:Female; D007472:Iohexol / Q000009:adverse effects*; D008279:Magnetic Resonance Imaging / Q000662:veterinary; D008297:Male; D009942:Organometallic Compounds / Q000009:adverse effects*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000662:veterinary
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol; D007472:Iohexol
keywords: cat; contrast media; dog; reaction