The measurement of limb blood flow using technetium-labelled red blood cells

Abstract

A method for measuring blood flow below the knee during reactive hyperaemia induced by 3 min of arterial occlusion has been developed. Subjects are positioned with lower limbs within the field of view of a gamma camera and pneumatic cuffs are placed below the knees to isolate the blood and induce a hyperaemic response. The remaining blood pool is labelled with 99Tcm-labelled red cells. Blood flows have been derived from the initial gradients of time-activity curves and from equilibrium blood sampling. The technique has been validated using a tissue-equivalent leg phantom and peristaltic pump. The method has been applied to a small group of patients with peripheral vascular disease and to normal controls. The mean value (+/- SD) of limb perfusion for normal controls was found to be 16.4 +/- 3.0 ml/100 ml/min and for patients with intermittent claudication was 5.1 +/- 2.6 ml/100 ml/min. Flow measurements are found to correlate with clinical findings and with symptoms. Reproducibility (established by repeated measurements) is high. The method is well tolerated even by patients suffering from rest pain.

Haemodynamic and metabolic responses of the lower limb after high intensity exercise in humans

“…This study has not only determined, for the first time, the common femoral artery flow profile following such a high intensity exercise test but also addressed the changes in blood S. T. HLJSSAIN AND OTHERS flow distribution induced by muscular exercise beyond the CFA bif'urcation. Resting CFA flow was found to be 314 + 79 ml min-1; this is within the range determined by other techniques (Agrifolio et al 1961;Hobbs & Edwards, 1963;Parkin et al 1986). -Approximately onethird of the flow in the CFA at rest is distributed to the PFA (99 + 18 mlmrin-), the main arterial supply to the thigh, and two-thirds of the flow to the SFA (219 + 65 ml min-'), the main arterial supply to the lower leg.…”

“…Other methods typically evaluate either segmental or total limb blood flow. Techniques such as indicator dilution (Agrifolio, Thorburn & Edwards, 1961), radiolabelled isotope (Parkin, Robinson & Wiggins, 1986), electromagnetic flowmetry (Sako, 1982) and occlusion plethysmography (Landowe & Katz, 1942) are either episodic, invasive or prone to inaccuracies and technical difficulties. In contrast, duplex Doppler ultrasound can be used to measure beat-by-beat flow in individual major vessels (Lewis et al 1986).…”

Measurement of skeletal muscle perfusion during postischemic reactive hyperemia using contrast‐enhanced MRI with a step‐input function

“…Strain gauge studies provide only global limb as opposed to regional muscle flow information, are hampered by systematic underestimation of flow, and are sensitive to patient positioning and temperature (3). Scintigraphy and positron‐emission tomography (PET) can be used to estimate skeletal muscle blood flow using inflow of tracers (4–6); however, they provide relatively low spatial resolution. Numerous MRI approaches can be used to noninvasively measure regional blood flow in skeletal muscle, including arterial spin labeling (ASL) (7–10), tissue relaxometry (7, 8, 11), and first‐pass signal enhancement with paramagnetic tracers (12–14).…”

“…Because resting perfusion in skeletal muscle is relatively low, highly variable, and not indicative of pathology, the first‐pass studies were designed for application during a period of increased blood flow during postischemic reactive hyperemia following an arterial occlusion. The first goal of this study was to validate a method for contrast agent delivery that provides an arterial step‐input of contrast concentration that coincides with the onset of reactive hyperemia (6). This approach was designed both to allow flow measurements to be made during the period of peak hyperemic flow, and to eliminate the need for deconvolution of arterial and tissue time‐intensity curves in order to estimate flow.…”

Scintigraphic method for evaluating reductions in local blood volumes in human extremities

“…The purpose of our study was to establish a method for measuring limb blood volume changes as a result of physiological exsanguination. The new method is based on the combined use of 99mTclabelled erythrocytes [21] and a tourniquet for clamping the residual blood volume.…”