Bone lesions in ECD. The red arrows show: (A) Whole-body bone scan with technetium-99 showing avid uptake in the knees and left hip of an ECD patient. Less intense uptake occurs bilaterally in the humeri and distal tibias. (B) FDG PET-CT scan showing increased FDG uptake in the knees and proximal and distal tibias. (C) Bone radiograph showing cortical osteosclerosis in the right humeri. (D) Bone radiograph showing cortical osteosclerosis in the distal right radius. (E) CT scan of the right knee of an ECD patient showing cortical osteosclerosis and mottled appearance of the bone. (F) MRI scan of the right knee of an ECD patient showing serpiginous areas of T1 signal hypointensity, indicative of osteosclerosis. (G) Panoramic radiograph showing bilateral osteosclerosis of the mandible and maxillary sinus disease.