Bone blood flow measurement — 1: Indicator dilution

Abstract

Interest in bone blood flow measurement includes its certain involvement in normal bone growth and decay, and fracture repair, as well as incorporating the entire spectrum of bone disease. It is only now, after 60 years of trial and error, that bone haemodynamic parameters can be quantified in bone with any degree of reliability. Unfortunately, however, skeletal flow values reported from different laboratories, even when using comparable methods, often show considerable diversity. To some extent therefore it seems that the results of skeletal haemodynamic investigations demonstrate some operational dependency. In spite of this cautionary note, it is now possible with confidence, using the very few methods which have withstood the test of time, to investigate the linkage between the osseous circulation in normal bone growth and metabolism and the often profound pathological changes which occur concurrently with a disturbed circulation. Although contemporary research tends to focus on the metabolic cellular and biochemical controlling factors associated with bone vascular status, it is worth bearing in mind that a change in the rate of blood perfusion through a bone, reflecting an alteration in the balance of arterial input and venous outflow, has direct and significant effects on the biophysical environment of bone cells; thus pH, ${P_{C{O_2}}}$, ${P_{{O_2}}}$ and interstitial fluid flow may all be affected, with concomitant effects on cellular function.