title: Correlation between magnetic resonance imaging and ultrasound measurements of eye muscle thickness in thyroid-associated orbitopathy.
abstract: OBJECTIVE
  To compare ultrasound (US) and magnetic resonance imaging (MRI) measurements of horizontal eye muscle thickness in patients with thyroid-associated orbitopathy (TAO) and to compare these measurements according to the phase of the disease, the severity of exophthalmos, and the experience of the investigator.
  
  
  METHODS
  A total of 180 orbits of adult patients with TAO were investigated from May 2007 to December 2012. In addition to their general ophthalmic examination, all patients underwent ultrasonographic measurement of horizontal eye muscle thickness with the B-scan technique and MRI examination of the orbit. Correlations between values obtained by US and MRI were determined for different subgroups according to disease activity (active, inactive), exophthalmos values (Hertel < 18 mm; Hertel 18-22 mm; Hertel > 22 mm), and the time period of examination (2007-2009; 2010-2012).
  
  
  RESULTS
  Positive moderate correlation between US and MRI values for the medial rectus muscle (MRM; r = 0.690) and for the lateral rectus muscle (LRM; r = 0.572) was found. Significantly higher correlation was found for the MRM (P < 0.0001) and the LRM (P = 0.0008) in the time period 2010-2012 than in that of 2007-2009. Increasing correlation was found for MRM with increasing values of exophthalmos but this increase was not statistically significant. In the active phase of the disease compared to the inactive phase, statistically significant increased correlation (P = 0.019) was found for the LRM.
  
  
  CONCLUSIONS
  Ultrasonographic measurement of horizontal eye muscles thickness in TAO moderately correlates with values obtained using MRI. The accuracy of ultrasonographic measurements in particular increases with the experience of the investigator.
authors: Department of Ophthalmology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Czech Republic.
authors: Marta
authors: M
authors: Karhanova
authors: Department of Radiology, Faculty of Medicine and Dentistry, Palacky University Olomouc.
authors: Radim
authors: R
authors: Kovar
authors: Department of Internal Medicine III - Nephrology, Rheumatology and Endocrinology, Faculty of Medicine and Dentistry, Palacky University Olomouc.
authors: Zdenek
authors: Z
authors: Frysak
authors: Department of Ophthalmology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Czech Republic.
authors: Martin
authors: M
authors: Sin
authors: Department of Medical Biophysics, Faculty of Medicine and Dentistry and Institute of Molecular and Translational Medicine, Palacky University Olomouc.
authors: Jana
authors: J
authors: Zapletalova
authors: Department of Ophthalmology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Czech Republic.
authors: Jiri
authors: J
authors: Rehak
authors: Department of Radiology, Faculty of Medicine and Dentistry, Palacky University Olomouc.
authors: Miroslav
authors: M
authors: Herman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005094:Exophthalmos / Q000209:etiology; D005260:Female; D049970:Graves Ophthalmopathy / Q000000981:diagnostic imaging*; D006801:Humans; D006984:Hypertrophy / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000592:standards; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000000981:diagnostic imaging*; D009915:Orbit / Q000000981:diagnostic imaging / Q000473:pathology*; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000592:standards; D055815:Young Adult
keywords: extraocular muscles; magnetic resonance imaging; orbit; thyroid-associated orbitopathy; ultrasound