Whole-body magnetic resonance imaging in the assessment of muscular involvement in juvenile dermatomyositis/polymyositis patients.

OBJECTIVES: Our aim was to demonstrate the benefit of whole-body magnetic resonance imaging (WBMRI) as a diagnostic modality in the detection of muscle activity in juvenile dermatomyositis (JDM)/polymyositis (JPM) patients and to correlate these findings with clinical evaluation, laboratory examinations, nailfold capillaroscopy (NFC), and muscle biopsy.

METHOD: Thirty-four patients aged 5.5 to 18.9 years with a diagnosis of JDM/JPM were prospectively evaluated using clinical examination, muscle enzyme determination, the Childhood Myositis Assessment Scale (CMAS), Disease Activity Score (DAS), Manual Muscle Testing (MMT), NFC, and WBMRI. An open muscle biopsy was performed if muscle disease activity was detected on WBMRI.

RESULTS: Disease activity was detected in WBMRI in four (11.7%) patients and confirmed by muscle biopsy. All four patients had elevation of at least one muscle enzyme and NFC showed scleroderma patterns in these patients.

CONCLUSIONS: WBMRI allows us to evaluate the extent and symmetry of muscle disease and inflammatory activity. NFC is an important additional examination to assess disease activity.