The distribution of radioactive microspheres after intra arterial injection in the legs of patients with peripheral vascular disease

Relative regional perfusion of the microcirculation of the extremities is demonstrated by scanning after an intra arterial injection of (99m)Tc labeled human serum albumin microspheres. The injections were most conveniently made just prior to peripheral angiography. Perfusion patterns ranged from those proportional to muscle masses to those proportional to skin surface. The former was seen in normals, while the latter was seen in patients with generalized vascular disease. Regions of increased radioactivity were observed in patients with focal disease such as Paget's disease of bone or dermatitis. Three basic scan patterns are described in which the radioactivity is distributed; proportional to muscle masses; asymmetrically with relative decreases in one or more muscle masses and diffusely diminished in the muscles or proportional to skin surface. Two supplemental patterns include regions of localized increased radioactivity to hyperemia of soft tissue lesions and diseased osseous structures.