High-resolution axial MR imaging of Group 3. MR imaging shows abnormal periosteal signals along the medial and medial-posterior surface of the tibia. Abnormal bone marrow signals extend through the entire bone marrow. Abnormal cortical signals are observed in the medial-posterior cortex (arrow heads). Periosteal hypertrophy is observed in the medial and medial-posterior aspect (arrow), indicating radiographic periosteal reaction.