Clinical evaluation of lower limbs of patients with venous insufficiency alone may not identify involved systems or anatomical sites, thus complementary tests are needed. These tests can be invasive or noninvasive. Invasive tests, such as phlebography and ambulatory venous pressure, despite being accurate, may produce discomfort and complications. Some of the most used noninvasive tests are continuous wave Doppler ultrasound, photoplethysmography, air plethysmography and duplex scanning. Doppler ultrasound assesses blood flow velocity indirectly. Photoplethysmography assesses venous refilling time, providing an objective parameter of venous reflux quantification. Air plethysmography allows quantification of reduction in venous capacitance, reflux and performance of the calf muscle pump. Duplex is considered a gold standard among noninvasive methods, because it allows quantitative and qualitative evaluation, supplying anatomical and functional information, thus providing a more complete and detailed evaluation of both deep and superficial venous system.
Diagnosis; venous insufficiency; ultrasonics; plethysmography