Fig. 1

Patient 1: X-ray images showed multiple cystic low density areas (blue circle) of distal right femur and proximal tibia (a, b). PDWI sequence of MRI showed effusion and synovial thickening of the right knee joint, and subchondral bone marrow edema (blue circle) of the distal femur and proximal tibia (c–e). Post-treatment X-ray images showed the low density area was significantly reduced (f, g). Post-treatment PDWI sequence of magnetic resonance images indicates the high signal area of bone marrow edema had disappeared (h–j)