FIGURE 101.4 Coronal fast multiplanar inversion recovery image of the thighs shows areas of increased signal intensity, especially in the adductor muscle groups, in a patient with dermatomyositis Weakness is a consistent manifestation of JDM, but it is a variable and subjective clinical sign Objective evidence of muscle inflammation should also be sought by measuring serum levels of muscle enzymes A wide variety of enzymes may be elevated in JDM, including creatine kinase (CK), aldolase, lactate dehydrogenase (LDH), and transaminases (ALT and AST) These markers must be interpreted with caution, however, because none is specific for muscle Further, for unknown reasons many children not reliably demonstrate elevated muscle enzymes despite significant myositis This is particularly true during later stages of the disease, when subtle increases in LDH and aldolase may herald a disease flare-up, but CK levels often remain normal While myositis-specific antibodies (MSAs) have demonstrable utility in the diagnosis of adult DM, their utility in pediatric cases is an area of active