Radionuclide evaluation of peripheral circulatory dynamics: new clinical application of blood pool scintigraphy for measuring limb venous volume, capacity, and blood flow.

A new application of clinical blood pool imaging is described for measurements of limb venous volume and blood flow. Forearm count rate changes determined using blood pool imaging of in vivo Tc-99m labelled red blood cell (RBC) were compared in the same limb to forearm volume changes measured by Whitney mercury-in-silicone rubber strain gauge in eight normal subjects. Intravascular count rate changes closely correlated with volume changes following sudden (mean r = 0.98) and stepwise (mean r = 0.96) limb venous congestion for assessment of venous compliance, as well as for measurement of limb blood flow up to 20 ml/min/100 ml (r = 0.95). These results indicate the accuracy and utility of the radionuclide technique in the study of peripheral circulatory dynamics in clinical settings. In addition, limb tissue fluid accumultion may also be quantified by simultaneous use of radionuclide-strain gauge plethysmography.