Bone scintigraphic changes in osteonecrosis of the femoral head

Bone scanning with 99mTc will detect osteonecrosis of the femoral head before changes appear in conventional radiographs. There is no liner correlation between the intensity of the scintigraphic picture and the clinical stage of the disease. The 99mTc labels newly formed hydroxyapatite crystals and may be helpful in detecting disease in a contralateral asymptomatic hip or confirming the diagnosis in the suspected hip.