[Ultrasound duplex an important tool in diagnosis of vascular diseases]

Ultrasound duplex scanning has caused a revolution to noninvasive diagnostics of disease in arteries and veins. A duplex examination (duplex = gemini, twin) initially implied the use of a combination of black and white 2D image and spectral Doppler, but now also includes colored directional Doppler and energy (nondirectional) Doppler. Late ultrasound developments are: low frequency (tissue) Doppler, 2nd harmonics image and doppler, contrast enhancement of blood flow, 3- and 4 dimensional reconstruction of image and flow, and compound imaging, every modality with new and improved information. It is possible to image the arterial and venous circulation in detail, including the vessel wall and the atherosclerotic atheroma, viewing both anatomical, functional, dynamic and mechanical properties. Furthermore, it is possible to use low-energy diagnostic ultrasound for intervention, for example to enhance thrombolysis. Duplex scanners now are used as the prime diagnostic tool in vascular laboratories. Even for traditionally morphological diagnostic purposes, flow information is valuable. A duplex examination is normally entirely noninvasive and nontraumatic, and thus without risks or discomfort for the patient. The technic has improved gradually and now may complement or even replace angiography and venography, for example for detection of carotid, iliac and femoral stenosis, venous insufficiency and venous thrombosis. As the examination is performed in real time, momentary flow and wall movements may be studied, for example during exercise and in drug research.