title: Assessment of optic nerve compression in Graves' ophthalmopathy. The usefulness of a quick T1-weighted sequence.
abstract: OBJECTIVE
  Diagnosis of optic nerve compression can be difficult in patients with equivocal clinical signs. We examined the usefulness of a quick coronal MR sequence performed at a predetermined plane as a screening tool for selecting patients at high risk of optic nerve compression.
  
  
  METHODS
  Direct coronal images of the orbit were obtained in 37 patients with Graves' disease in a predetermined plane. The muscular indices (MI) of each orbit were calculated. Mann-Whitney U-Wilcoxon rank sum test was used to assess if there was any statistically significant difference between patients with and without signs of optic nerve compression. The ROC curve was used to identify a value useful for discriminating patients with a higher risk of developing optic nerve compression.
  
  
  RESULTS
  There was a statistically significant difference (p<0.05) in the MI between patients with and without optic nerve compression. An MI of -0.48 had 100% sensitivity, 89% specificity and 91% accuracy in identifying patients with optic nerve compression. CONCLUSION. A quick coronal MR image obtained at the mid-orbital plane is useful in screening patients with Graves' disease for optic nerve compression.
authors.affiliation: Department of Diagnostic Radiology and Organ Imaging, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital Shatin, New Territories.
authors.forename: N M
authors.initials: NM
authors.lastname: So
authors.forename: W W
authors.initials: WW
authors.lastname: Lam
authors.forename: G
authors.initials: G
authors.lastname: Cheng
authors.forename: C
authors.initials: C
authors.lastname: Metreweli
authors.forename: D
authors.initials: D
authors.lastname: Lam
mesh_terms: D005260:Female; D006111:Graves Disease / Q000150:complications* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009408:Nerve Compression Syndromes / Q000175:diagnosis* / Q000209:etiology; D009801:Oculomotor Muscles / Q000473:pathology; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000209:etiology; D009915:Orbit / Q000473:pathology; D012372:ROC Curve; D012680:Sensitivity and Specificity