Radiographic and MR imaging of Group 2. [A] Initial radiographic examination shows no periosteal reaction. [B] Follow-up radiographic examination shows local peroneal reaction. High-resolution axial MR imaging using proton-density WI [C], T2* WI [D] and fat-suppressed T2 WI [E] shows abnormal periosteal signals along the medial-posterior surface of the tibia. Abnormal bone marrow signals exceed the entire tibial bone marrow. MR imaging shows cortical abnormal signals in the medial-posterior part of the tibia (arrow heads). Axial [F] and coronal [G] fat-suppressed T2 WI MR imaging using conventional coil shows whole tibial bone marrow and surrounding soft tissues. High-resolution imaging is useful to detect signal changes of the regional tissues.