title: Preoperative imaging to predict orbital invasion by tumor.
abstract: BACKGROUND
  Our purpose was to examine the accuracy of preoperative imaging in assessing tumor invasion of the orbit and nasolacrimal system.
  
  
  METHODS
  Nineteen preoperative CT and 17 preoperative MR images from patients at risk for orbital invasion were retrospectively reviewed. Invasion was corroborated by pathologic and intraoperative assessment.
  
  
  RESULTS
  Tumor adjacent to the periorbita was the most sensitive predictor of orbital invasion (90%) for both CT and MRI. Extraocular muscle involvement on MRI (100%) and orbital fat obliteration (80% MRI, 86% CT) had the highest positive predictive values of the criteria evaluated. Extraocular muscle displacement and enhancement were less accurate (<65%) predictors. No one criterion was >79% accurate in predicting orbital invasion. Six or more positive criteria predicted invasion with 67% sensitivity and 80% specificity (accuracy, 72%). CT was more accurate than MRI in seven of nine criteria. Invasion of the nasolacrimal system was predicted accurately (89%).
  
  
  CONCLUSIONS
  Although preoperative imaging can aid in surgical planning, it should not replace intraoperative assessment in ambiguous cases of orbital invasion.
authors.affiliation: Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania Medical Center, Philadelphia, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Eisen
authors.forename: D M
authors.initials: DM
authors.lastname: Yousem
authors.forename: L A
authors.initials: LA
authors.lastname: Loevner
authors.forename: E R
authors.initials: ER
authors.lastname: Thaler
authors.forename: W B
authors.initials: WB
authors.lastname: Bilker
authors.forename: A N
authors.initials: AN
authors.lastname: Goldberg
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D005260:Female; D005544:Forecasting; D006801:Humans; D007089:Image Enhancement; D007430:Intraoperative Care; D007766:Lacrimal Apparatus Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D009361:Neoplasm Invasiveness; D009669:Nose Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging; D009801:Oculomotor Muscles / Q000473:pathology; D009918:Orbital Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011856:Radiographic Image Enhancement; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed