Diagnosis of popliteal artery entrapment syndrome: the role of duplex scanning. The authors present a new diagnostic procedure to quickly and noninvasively diagnose the popliteal artery entrapment syndrome. A large personal experience on the surgical treatment of such a disease (29 cases in 22 patients) allowed us to focus on the optimal diagnostic procedure useful to detect this problem at an early stage. The technique is based on continuous-wave Doppler and duplex scanning studies done both in the resting state and during active contraction of the calf muscles. If compression of the popliteal artery occurs with contraction of the calf muscles, it will be detected by a decrease in flow. This finding will also direct the radiologist to obtain films when the maneuver is repeated. This makes it unlikely that the diagnosis will be missed. Since July 1988 a total of 1212 patients were evaluated with continuous-wave Doppler for suspected chronic ischemia. From this group 41 patients were selected to be studied again with the combined continuous-wave Doppler and duplex scanning method for possible popliteal artery entrapment syndrome. Two cases were discovered and verified by dynamic angiography guided by continuous-wave Doppler and treated surgically. 