title: Reliability and accuracy of skeletal muscle imaging in limb-girdle muscular dystrophies.
abstract: OBJECTIVE
  To evaluate the reliability and accuracy of skeletal muscle CT to correctly identify different muscular dystrophies manifesting with limb-girdle weakness.
  
  
  METHODS
  Four evaluators assessed scans from 118 patients with limb-girdle muscular dystrophy (LGMD) caused by mutations in 7 different genes and from 32 controls. The conditions studied were scans of genetically confirmed cases of Becker muscular dystrophy (BMD) (n = 28), LGMD2C-F (sarcoglycanopathies) (n = 11), LGMD2I (n = 4), LGMD1B (n = 26), LGMD2A (n = 24), Bethlem myopathy (n = 14), and LGMD2L (n = 11). The control group (n = 32) consisted of patients with neuromuscular disorders manifesting with limb-girdle weakness in which the aforementioned muscular dystrophies were excluded. The scans were compared with the characteristic patterns described in literature.
  
  
  RESULTS
  The overall interobserver agreement was poor (κ = 0.27), with markedly higher scores for BMD (κ = 0.51) and Bethlem myopathy (κ = 0.59). The sensitivity to detect selective patterns in relation to the genetic diagnosis was 40% if all LGMDs were taken together. The specificity was 58%, positive predictive value (PPV) 77%, and 1 - negative predictive value (NPV) 79%. Markedly better scores were observed for BMD (sensitivity 91%, PPV 66%, 1 - NPV 3%) and Bethlem myopathy (sensitivity 90%, PPV 69%, 1 - NPV 1%).
  
  
  CONCLUSIONS
  Our findings suggest that muscle CT might be an adjunct to the clinical diagnosis of BMD and Bethlem myopathy. However, pattern recognition was cumbersome in the other LGMDs.
authors.affiliation: Department of Neurology, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Leroy
authors.initials: L
authors.lastname: ten Dam
authors.forename: Anneke J
authors.initials: AJ
authors.lastname: van der Kooi
authors.forename: Menno
authors.initials: M
authors.lastname: van Wattingen
authors.forename: Rob J
authors.initials: RJ
authors.lastname: de Haan
authors.forename: Marianne
authors.initials: M
authors.lastname: de Visser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000209:etiology*; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000473:pathology*; D049288:Muscular Dystrophies, Limb-Girdle / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology; D020388:Muscular Dystrophy, Duchenne / Q000175:diagnosis; D020389:Muscular Dystrophy, Emery-Dreifuss / Q000175:diagnosis; D009154:Mutation; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D058088:Sarcoglycanopathies / Q000175:diagnosis; D014057:Tomography, X-Ray Computed; D055815:Young Adult