title: Assessment of ultrasonography and computed tomography for the evaluation of unilateral orbital disease in dogs.
abstract: OBJECTIVE
  To describe clinical, ultrasonographic, and computed tomographic (CT) features of confirmed neoplastic and nonneoplastic disease in dogs with unilateral orbital diseases, determine criteria to differentiate between the 2 conditions, and assess the relative value of ultrasonography and CT for the differential diagnosis of these 2 conditions.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  29 dogs with unilateral neoplastic orbital disease and 16 dogs with unilateral nonneoplastic orbital disease.
  
  
  METHODS
  Clinical history and results of physical and ophthalmologic examinations were recorded. Ultrasonographic and CT images were evaluated, and discriminating factors were identified to differentiate neoplastic from nonneoplastic diseases. Diagnostic value of ultrasonography and CT was assessed.
  
  
  RESULTS
  Dogs with neoplastic disease were significantly older; had clinical signs for a longer time before initial examination; had more progressive onset of clinical signs; and more frequently had protrusion of the nictitating membrane, fever, and anorexia. The most discriminating factor for both imaging modalities was delineation of the margins (odds ratio was 41.7 for ultrasonography and 45 for CT), with neoplastic lesions clearly delineated more often. Ultrasonographically, neoplastic lesions were more frequently hypoechoic and homogeneous, with indentation of the globe and bone involvement evident more frequently than for nonneoplastic lesions. Mineralization was detected only with neoplasia. Fluctuant fluid was seen more frequently in dogs with nonneoplastic disease. Computed tomography more frequently revealed extraorbital involvement. Diagnostic value was similar for both imaging modalities.
  
  
  CONCLUSIONS
  Ultrasonography and CT are valuable imaging modalities to assist in differentiating neoplastic from nonneoplastic unilateral orbital disease in dogs.
authors.affiliation: Division of Diagnostic Imaging, Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3508 TD, Utrecht, The Netherlands.
authors.forename: Susanne A E B
authors.initials: SA
authors.lastname: Boroffka
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Verbruggen
authors.forename: Guy C M
authors.initials: GC
authors.lastname: Grinwis
authors.forename: George
authors.initials: G
authors.lastname: Voorhout
authors.forename: Paul Y
authors.initials: PY
authors.lastname: Barthez
mesh_terms: D000367:Age Factors; D000818:Animals; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D004285:Dogs; D005260:Female; D008297:Male; D016017:Odds Ratio; D009916:Orbital Diseases / Q000000981:diagnostic imaging / Q000473:pathology / Q000662:veterinary*; D009918:Orbital Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000662:veterinary*; D011446:Prospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000662:veterinary*; D014463:Ultrasonography / Q000379:methods / Q000662:veterinary*