title: Microscopic Evaluation of Peritumoral Lesions of Feline Injection Site Sarcomas Identified by Magnetic Resonance Imaging and Computed Tomography.
abstract: OBJECTIVE
  Determine whether dual-phase computed tomography angiogram (CTA) or magnetic resonance imaging (MRI) detect more peritumoral lesions of feline injection site sarcoma (FISS) and determine whether CTA or MRI imaging characteristics of peritumoral lesions correspond with microscopic findings.
  
  
  METHODS
  Prospective clinical study.
  
  
  METHODS
  Ten client-owned cats with FISS.
  
  
  METHODS
  A fiducial marker detectable on CTA and MRI was sutured to the skin over the FISS as a standard reference point. All cats received MRI and CTA of the FISS, immediately followed by wide surgical excision. Targeted microscopic evaluation was performed on tissue with imaging-identified lesions and on the surgical margins.
  
  
  RESULTS
  A total of 87 imaging-identified peritumoral lesions were examined microscopically (median 4 per cat, range 3-9) with 17/87 (20%) categorized as neoplastic, 51/87 (59%) as nonneoplastic, and 19/87 (22%) as equivocal. In 25 instances, peritumoral lesions were seen on both imaging modalities at the same location. Unique imaging characteristics were seen in 5/17 neoplastic peritumoral lesions (4 cats; all different lesions; 1 CTA, 4 MRI). The CTA and MRI appearances of the remaining 12/17 neoplastic lesions were nonspecific, being observed across more than 1 microscopic category.
  
  
  CONCLUSIONS
  CTA and MRI identified a similar number of peritumoral lesions. The extensive overlap between imaging features of neoplastic and nonneoplastic lesions precludes definitive identification of neoplastic peritumoral FISS lesions using CTA or MRI.
authors.affiliation: College of Veterinary Medicine, Oregon State University, Corvallis, Oregon.
authors.forename: Sarah
authors.initials: S
authors.lastname: Nemanic
authors.affiliation: College of Veterinary Medicine, Oregon State University, Corvallis, Oregon.
authors.forename: Milan
authors.initials: M
authors.lastname: Milovancev
authors.affiliation: College of Veterinary Medicine, Oregon State University, Corvallis, Oregon.
authors.forename: Jesse L
authors.initials: JL
authors.lastname: Terry
authors.affiliation: College of Veterinary Medicine, Oregon State University, Corvallis, Oregon.
authors.forename: Susanne M
authors.initials: SM
authors.lastname: Stieger-Vanegas
authors.affiliation: College of Veterinary Medicine, Oregon State University, Corvallis, Oregon.
authors.forename: Christiane V
authors.initials: CV
authors.lastname: Löhr
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D002415:Cats; D005260:Female; D006614:Hindlimb; D008279:Magnetic Resonance Imaging / Q000662:veterinary; D008297:Male; D011446:Prospective Studies; D012509:Sarcoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000662:veterinary*; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000662:veterinary*; D014057:Tomography, X-Ray Computed / Q000662:veterinary