Objective
To investigate the diagnostic validity of doppler ultrasonography (US) and impedance plethysmography (IPG) using photoplethysmography for evaluation of varicose vein of the lower extremities.

Method
One hundred sixty-six limbs in 83 consecutive patients with varicose vein were included. Venous reflux and deep venous lesions were assessed by doppler US. Venous filling time was evaluated using IPG. Diagnostic capabilities of two methods were analyzed using Receiver Operating Characteristic (ROC) curve.

Results
Doppler US identified superficial venous reflux in sixty-nine of 119 limbs with varicose vein and no abnormalities in 34 of 47 normal limbs (sensitivity, 58%; specifi-city, 75%). IPG demonstrated superficial venous insufficiency in 75 of the affected limbs and normal refill time in 38 of the normal limbs (sensitivity, 63%; specificity, 81%). Sensitivity was increased to 82% when both tests were used together. Area under the ROC curve was 0.66 in doppler US, 0.72 in IPG, and 0.76 in both tests. Deep venous lesion was found in 31 limbs using the both tests; 15 limbs with doppler US and 18 limbs with IPG.

Conclusion
IPG was more superior to doppler US in diagnosing venous insufficiency. The combination of both tests provided more accurate diagnostic information in assessing venous valvular function. (J Korean Acad Rehab Med 2002; 26: 337-341)