Muscle Blood Flow in Normal Man and in Patients with Intermittent Claudication Evaluated by Simul - taneous

Intramuscular injection of a small amount of radioactive sodium (Na24) was used by Kety as an index of local blood flow in skeletal muscle (1, 2). The hydrophilic sodium ions are known to exchange fairly slowly over many biological membranes, in contrast to the lipophilic inert gases to which such membranes offer no diffusion barriers (3). Hence a radioactive inert gas such as xenon'33 is probably a better indicator of blood flow than Na24. Recent clinical studies with intramuscular injection of Xe'33 dissolved in saline have tended to support this conclusion (4, 5). However, the possible superiority of employing Xe'33 instead of Na24 is best evaluated by using the two tracers simultaneously. Forty such simultaneous observations in ten normal subjects and in ten patients with intermittent claudication are reported in the present study.