Whole-body MRI in the assessment of disease activity in juvenile dermatomyositis

• Published in: Annals of the rheumatic diseases Vol. 73; no. 6; pp. 1083 - 1090
• Main Authors: Malattia, Clara, Damasio, Maria Beatrice, Madeo, Annalisa, Pistorio, Angela, Providenti, Anna, Pederzoli, Silvia, Viola, Stefania, Buoncompagni, Antonella, Mattiuz, Chiara, Beltramo, Agnese, Consolaro, Alessandro, Ravelli, Angelo, Ruperto, Nicolino, Picco, Paolo, Magnano, Gian Michele, Martini, Alberto
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01.06.2014
• Subjects: Adolescent; Case-Control Studies; Child; Cohort Studies; Dermatomyositis - diagnosis; Dermatomyositis - pathology; Fascia - pathology; Feasibility Studies; Female; Humans; Inflammation; Inflammation - pathology; Legs; Magnetic Resonance Imaging - methods; Male; Muscle, Skeletal - pathology; Physical Examination; Quality of life; Reproducibility of Results; Rheumatology; Severity of Illness Index; Studies; Subcutaneous Tissue - pathology; Validity; Whole Body Imaging; Magnetic Resonance Imaging; Disease Activity; Dermatomyositis
• ISSN: 0003-4967; 1468-2060
• DOI: 10.1136/annrheumdis-2012-202915

Objective To compare whole-body MRI (WB-MRI) with clinical examination in the assessment of disease activity in juvenile dermatomyositis (JDM). Methods WB-MR images were obtained from 41 JDM patients and 41 controls using a 1.5 T MRI scanner and short τ inversion recovery sequences. 18 patients had follow-up WB-MRI. Muscle, subcutaneous tissue and myofascial signal abnormalities were scored in 36 muscular groups and on proximal and distal extremities. WB-MRI and clinical assessments were performed concurrently and results compared. Validation procedures included analysis of feasibility, reliability, construct validity, discriminative ability and responsiveness. Results WB-MRI revealed distal legs (26/41 patients) and forearm (19/41 patients) muscle inflammation undetected during clinical examination and allowed an accurate assessment of subcutaneous (23/41 patients) and myofascial involvement (13/41 patients). 27 patients showed a patchy distribution of muscle inflammation while in seven the abnormal hyperintense areas tended to be homogeneously distributed. The inter-reader agreement for muscular, subcutaneous and myofascial WB-MRI scores was excellent. Correlations between WB-MRI muscle score and disease activity measures were excellent (Manual Muscle Test: rs=−0.84, Childhood Myositis Assessment Scale: rs=−0.81). WB-MRI score was higher in JDM active patients when compared with the control group (pB<0.0001) and the inactive patients (pB=0.004), and showed an excellent responsiveness (standardised response mean=1.65). Follow-up WB-MRI showed resolution of inflammation in nine patients whereas clinical criteria for remission were satisfied in five. Conclusions WB-MRI provides additional information to clinical evaluation and represents a promising tool to estimate total inflammatory burden, tailor treatment and monitor its efficacy.