Use of a gamma camera for measuring limb blood flow in peripheral vascular disease

A method for measuring limb blood flow during reactive hyperaemia is described. Pneumatic cuffs inflated to 300 mmHg are used to isolate the blood in the limbs from the rest of the circulation. The remaining blood is labelled with technetium. The increase in radioactivity in the limb following release of the cuffs is measured using a gamma camera. The mean rate of flow of blood to the limb (in ml (100 ml)-1 tissue min-1) is derived from the graph of radioactivity versus time and from the radioactivity in a sample of venous blood. The results of measurements carried out in patients with peripheral vascular disease (30 limbs) and normal controls (24 limbs) are presented. Repeated studies in 10 subjects (20 limbs) showed the method to be highly reproducible at high and low flow rates (r = 0.99). Case studies illustrating the use of the method as a screening test for peripheral vascular disease and to monitor the effects of treatment are presented.