Measurement of skeletal flow with positron emission tomography and F-18-fluoride in femoral head osteonecrosis

Positron emission tomography (PET) with 18F-fluoride was utilized to determ ine the regional blood flow to the femoral head in early osteonecrosis. Fiv e patients with a history of unilateral hip trauma and a normal contralater al side were selected. Skeletal flow and fluoride uptake in the abnormal an d normal hips were compared directly, and the relation between bone blood f low and final outcome, i.e., surgical replacement or conservative treatment , was evaluated. In this pilot study, a flow ratio of at least 2 between th e abnormal and normal femoral head was necessary to predict a successful ou tcome with a conservative regimen. A minimum flow of 0.04 ml/min/ml was mea sured in one patient whose affected femoral head healed conservatively. Our preliminary study indicates that this type of highly technical investigati on appears feasible in clinical practice and permits prediction of the outc ome depending upon regional skeletal flow measurements in vivo.