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Thứ Ba, 21 tháng 8, 2018

Doppler Ultrasonography of the Lower Extremity Arteries

https://www.e-ultrasonography.org/upload/usg-16054.pdf

Doppler ultrasonography of the lower extremity arteries is a valuable technique, although it is less frequently indicated for peripheral arterial disease than for deep vein thrombosis or varicose veins. Ultrasonography can diagnose stenosis through the direct visualization of plaques and through the analysis of the Doppler waveforms in stenotic and poststenotic arteries. To perform Doppler ultrasonography of the lower extremity arteries, the operator should be familiar with the arterial anatomy of the lower extremities, basic scanning techniques, and the parameters used in color and pulsed-wave Doppler ultrasonography.

Doppler US is the only noninvasive technique that does not require contrast enhancement, preparation of the patient before the study, or radiation exposure [1,2]. Doppler US is a good method for screening and follow-up, as well as for the definitive diagnosis of peripheral arterial disease [3-7]. Color Doppler US can easily identify arteries by finding round objects with regular pulsation and can be used to detect stenotic or occluded segments [4,8]. Pulsed-wave Doppler US can show the exact flow velocity of each arterial segment and determine the degree of severity of the stenosis based on an analysis of the pulsed-wave Doppler spectral waveform [9]. Knowledge of the ultrasonographic anatomy of the lower extremity arteries and the corresponding anatomical landmarks is essential for performing Doppler US. In this article, we review the basic scanning techniques of color and pulsed-wave Doppler US for the lower extremity arteries and the spectral analysis of normal and stenotic arteries on pulsed-wave Doppler US.







Conclusion 

Doppler US has been found to distinguish between stenosis with a diameter reduction greater than or less than 50% (corresponding to an area reduction of 70%) with a sensitivity of 77%-82% and a specificity of 92%-98% [18,20-24]. Complete scanning of both lower extremities may require up to 2 hours depending on the operator’s experience [18]. However, if the operator is familiar with the US anatomy of the lower extremity arteries and understands the parameters and Doppler waveforms of Doppler US, accurate diagnostic results can be produced with less scanning time.

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