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Updated: May 28, 2026
Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
Assessment of active inflammation in juvenile dermatomyositis: a novel magnetic resonance imaging-based scoring
Warren R Davis1, James E Halls, Amaka C Offiah
1Radiology Department, Royal London Hospital, London, UK. dr.warren.davis@googlemail.com
Insights
This study found that a new MRI scoring system for juvenile dermatomyositis (JDM) shows reliable results for individual readers. However, agreement between different radiologists was only fair to moderate.
Area of Science:
- Radiology
- Pediatric Rheumatology
- Medical Imaging
Background:
- Juvenile dermatomyositis (JDM) is a rare autoimmune disease affecting children.
- Objective assessment of inflammatory changes in JDM is crucial for diagnosis and management.
- Current assessment methods may lack standardization.
Purpose of the Study:
- To evaluate the reproducibility of a novel, objective MRI scoring system for acute inflammatory changes in JDM.
- To assess inter-observer and intra-observer agreement for the scoring system.
Main Methods:
- Retrospective analysis of MRI studies from 48 children with JDM.
- Two musculoskeletal pediatric radiologists independently assessed disease activity markers.
- Kappa analysis for inter-observer agreement and Bland-Altman analysis for reproducibility were performed.
Main Results:
- Fair to moderate inter-observer agreement was found for disease activity markers.
- Good intra-observer agreement was observed between repeated readings by the same radiologist.
- The scoring system demonstrated acceptable accuracy for single readers, with variability between different individuals.
Conclusions:
- The developed MRI scoring system provides a reliable method for assessing inflammatory markers in JDM.
- The system is accurate for individual readers but shows more variability between different assessors.
- Further refinement may be needed to improve inter-observer reliability.
Objective:
To assess the reproducibility of a novel scoring system that we have developed for the objective assessment of acute inflammatory change in JDM. This system defines markers of inflammatory change in four muscle groups and the surrounding soft tissues.
Methods:
Forty-eight children (33 girls) underwent retrospective assessment of their MRI studies by two musculoskeletal paediatric radiologists for the presence of disease activity. Each observer performed the readings on two separate occasions. The degree of concordance between the two observers and between the two readings was assessed using kappa analysis. The reproducibility of the total score was determined using Bland-Altman analysis.
Results:
There was fair to moderate agreement between the two observers for all the examined disease activity markers in all muscle groups. There was good intra-observer agreement between the two readings. There was no difference according to the side evaluated. The mean total score (out of 20) for Observer 1 was 7.9 and for Observer 2 was 7.5 (mean difference -0.4, 95% limits of agreement -6.8 to 6.0), while the mean total scores for Observer 1 were 9.0 for the first reading and 7.9 for the second reading (mean difference 1.0, 95% limits of agreement -2.6 to 4.6).
Conclusion:
Markers of inflammatory change in JDM can be observed on MRI in a reliable fashion and have been used to make a reliable and objective scoring system. The accuracy of the proposed scoring system is acceptable for the single reader, although there is more variability between two different individuals.
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