Objectives To assess the scope of photoplethysmography (PPG), color duplex ultrasonography, percutaneous transpopliteal venography for evaluating chronic venous disease.

• 目的了解双功彩超、经皮腘静脉穿刺造影、光电容积描记（PPG）在检测下肢静脉倒流中的优缺点及相对适应证。