A new noninvasive approach to peripheral vascular disease: thallium-201 leg scans.

A new noninvasive technique to evaluate blood flow distribution to the legs is described. Intravenous thallium-201 is used during rest and exercise followed by scanning and point counting of the lower extremities. The normal blood flow distribution recorded in 30 patients with no known peripheral vascular disease was primarily proportional to muscle mass. Using both scans and point counting, normal intra- and interextremity ratios were qualitatively and quantitatively defined, and significant increases in muscular to nonmuscular perfusion with exercise were documented. The symmetry in perfusion in the contralateral muscle groups was verified for the first time.