The study of the hemodynamics in femoral heads by positron emission tomography

Evaluation of the hemodynamics in bone tissue is important for clarifying the pathogenesis and pathology of necrotic disease. However, there is no established method of non-invasive quantitative measurement of the blood flow in bone tissue. In addition, the blood volume representing the vascular bed volume is difficult to measure and remains unclear. To evaluate the applicability of positron emission tomography (PET) to the measurement of the blood flow and blood volume in bone tissue, we measured the blood flow and blood volume in the femoral head and evaluated age-associated hemodynamic changes in healthy adult males. The subjects were 16 healthy adult males (31 hip joints) and 1 male (2 hip joints) with trauma who underwent unilateral prosthetic replacement of the femoral head. Their age ranged from 20 to 78 years (mean, 42 years). The blood flow was measured by the dynamic study method using H215O while the blood volume was measured by the steady state method using C15O. The blood flow was 1.68-6.47 ml/min./100 g (mean±SD, 3.49±1.28), and the blood volume was 1.67-6.03 ml/100 ml (mean±SD, 2.99±1.25). With age the blood flow significantly decreased (p<0.01), and the blood volume significantly increased (p<0.05). Our results showed that the blood flow and blood volume in bone tissue can be measured in vivo by PET. Both the blood flow and blood volume in the femoral head considerably differed among individuals. The age-related changes in the femoral head may result from decreased trabecular bone with age and its replacement by blood. Though additional cases should be evaluated, PET is adequately applicable to experimental and clinical studies in orthopedic surgery. (author)