title: A review of orbital and intracranial magnetic resonance imaging in 79 canine and 13 feline patients (2004-2010).
abstract: OBJECTIVE
  To review the distribution of orbital and intracranial disease in canine and feline patients undergoing magnetic resonance imaging (MRI) following referral to a veterinary ophthalmologist and to correlate results of MRI with pathologic conditions including neoplasia, suspected optic neuritis (ON) and orbital cellulitis. Recognized and emerging imaging techniques are reviewed.
  
  
  METHODS
  Medical records of 79 canine and 13 feline patients were reviewed.
  
  
  RESULTS
  Neoplasia was diagnosed in 53/92 (57.6%) of patients. The most prevalent types of neoplasia were carcinoma (16/53, 30.1%), sarcoma (11/53, 20.8%), lymphoma (8/53, 15.1%) and presumptive meningioma (9/53, 17.0%). Carcinomas and sarcomas were characterized by bony lysis and intracranial/sinonasal extension. Lymphoma was generally unilateral, less invasive and originated from the ventromedial orbit. Intracranial masses representing presumptive meningiomas frequently exhibited a 'dural tail' sign. Diagnosis of suspected ON was made in 13 of 92 (14.1%) patients. Results of MRI in patients with suspected ON included unilateral optic nerve hyperintensity (3/13, 23.0%), bilateral optic nerve hyperintensity (1/13, 7.7%) and optic chiasmal hyperintensity (3/13, 23.0%). Seven suspected ON patients demonstrated intracranial multifocal patchy contrast enhancement (7/13, 53.8%). Diagnosis of orbital cellulitis was made in 12/92 (13.0%) patients.
  
  
  CONCLUSIONS
  Orbital neoplasia was the most common pathologic condition detected. Essential Roentgen characteristics are helpful when diagnosing pathologic processes and providing prognoses in cases of orbital or intracranial disease. Magnetic resonance imaging comprises an important diagnostic component in cases of suspected ON. Emerging contrast and functional MRI techniques as well as SI data may increase our ability to characterize disease processes.
authors: Eye Care for Animals, 3025 Edinger Ave, Tustin, CA 92780, USA. aarmour@eyecareforanimals.com
authors: Micki D
authors: MD
authors: Armour
authors: Michael
authors: M
authors: Broome
authors: Giuseppe
authors: G
authors: Dell'Anna
authors: Natalie J
authors: NJ
authors: Blades
authors: Douglas W
authors: DW
authors: Esson
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000175:diagnosis* / Q000473:pathology; D002415:Cats; D004283:Dog Diseases / Q000175:diagnosis* / Q000473:pathology; D004285:Dogs; D005260:Female; D008279:Magnetic Resonance Imaging / Q000662:veterinary*; D008297:Male; D009902:Optic Neuritis / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D054517:Orbital Cellulitis / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D009918:Orbital Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D012189:Retrospective Studies