Pediatric Rheumatology Online Journal → July 2003 → Dermatomyositis → Clinical Evaluation → Abstract #121
USE OF THE NOVEL MAGNETIC RESONANCE IMAGE TECHNIQUE OF T2 MAPPING IN THE MONITORING OF JUVENILE DERMATOMYOSITIS
P. Davis, C. Ryder, S. Wayte, K. Johnson
Background:
Juvenile dermatomyositis (JDMS) is a rare condition of childhood characterised by non-suppurative inflammation of striated muscle, and manifest by a symmetrical proximal muscle weakness. The majority of patients follow a uniphasic course, but a significant proportion will demonstrate a relapsing and remitting pattern. Immunosuppression is the main-stay of treatment. Response to treatment has conventionally been assessed by serial muscle strength testing and measurement of acute phase reactants and muscle enzymes. These methods however, may not differentiate between active muscle inflammation and chronic atrophy. Magnetic resonance imaging has been shown to be a sensitive tool in the diagnosis and monitoring of JDMS. We prospectively evaluated the role of magnetic resonance imaging in disease activity monitoring using the novel technique of T2 mapping.
Methods:
JDMS patients underwent routine MRI examinations to assess muscle involvement. The signal intensity values and T2 relaxation times were compared to muscle strength testing (by blinded assessors) using the Childhood Myositis Assessment Scale (CMAS) and to laboratory data (ESR, CRP, CK and LDH). Patients were re-assessed according to clinical need.
Results:
15 patients underwent 34 assessments. MRI T2 mapping showed significant negative correlation with CMAS scores, and significant positive correlation with lactate dehydrogenase measurements (correlation 0.602, p value 0.005) and ESR measurements (correlation 0.526, p value 0.021). However, there was no correlation between T2 mapping and CK (correlation 0.182, p value 0.444) or CRP measurements (correlation
Conclusions:
T2 relaxation times provide an objective score for monitoring disease activity in JDMS. MRI is well tolerated by patients. T2 mapping will facilitate both the management of patients between different centres and multi-centre research.