Fig. 1

MRI at time of diagnosis and flares. a and c showed the axial and coronal section of the first MRI at the time of diagnosis. It showed diffusely increased T2 signal throughout all the muscles of the thigh as well as of the pelvis and hip girdle region with symmetrical involvement except for more patchy involvement in the adductors and in semi-membranous and semi-tendinous muscles. b and d showed the axial and coronal section of the second MRI at the time of flare. It showed: bilateral increased intramuscular T2 signal within both posterior calves including the lateral head of the gastrocnemius, soleus, and medial head of gastrocnemius and plantaris muscles with corresponding areas of restricted diffusion. The degree of restricted diffusion and T2 prolongation has markedly decreased compared with initial MRI A and C. There is subtle T2 prolongation with corresponding restricted diffusion diffusely within the anterior thigh musculature involving the bilateral vastus lateralis, rectus femoris and subtly within the vastus medialis muscles