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: Leroy ten Dam, Anneke J van der Kooi, Menno van Wattingen, Rob J de Haan, Marianne de Visser
• Journal: Neurology (Neurology) Vol. 79 Issue 16 Pg. 1716-23 (Oct 16 2012) ISSN: 1526-632X [Electronic] United States
• PMID: 23035061 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Child
• Female
• Humans
• Magnetic Resonance Imaging
• Male
• Middle Aged
• Muscle Weakness (etiology)
• Muscle, Skeletal (diagnostic imaging, pathology)
• Muscular Dystrophies, Limb-Girdle (complications, diagnosis, diagnostic imaging, genetics, pathology)
• Muscular Dystrophy, Duchenne (diagnosis)
• Muscular Dystrophy, Emery-Dreifuss (diagnosis)
• Mutation
• Observer Variation
• Predictive Value of Tests
• Reproducibility of Results
• Sarcoglycanopathies (diagnosis)
• Tomography, X-Ray Computed
• Young Adult