The authors studied muscular blood flow (F), oxygen consumption rate (R), and oxygen extraction fraction (E) in 5 patients suffering from severe intermittent claudication (stage II). They applied the bolus technique of H2150 and 1502 with a detection by positron emission tomography (PET). Tomograms were recorded at the greatest diameter of the calves, at rest and ten minutes after a treadmill walk test leading to the development of ischemic pain in the affected extremity. F and E data were compared with the values obtained by more usual methods, namely occlusive venous strain gauge plethysmography and femoral venous blood sampling. During the study, these patients received naftidrofuryl, a vasodilatator drug, in an intravenous dose of 600 mg diluted in 250 mL saline infused over a six-hour period in a placebo-controlled, double-blind, crossover protocol (two consecutive experiments, a week apart). The results showed that all blood flow values measured at rest and after exercise by PET were in close correlation (r = 0.71) with the plethysmographic findings. The agreement between the two methods of measuring blood flow was less obvious with an Altman's presentation of the data: there was a tendency to measure higher values with PET scan. Concerning E, the correlation was poor at rest. After exercise, the values were more elevated with PET and no correlation was found with blood samples. The authors found no significant effect of naftidrofuryl either on flow or metabolic data.