3D Power Doppler Ultrasound Imaging of an in Vitro Arterial Stenosis
Several studies have reported that duplex scanning can be as accurate as angiography to predict and localize arterial stenoses. In spite of this promising performance, recent studies indicated a lower sensitivity for detecting significant stenoses distal to severe or total obstructions (1). The main reason proposed to explain this lower sensitivity is the difficulty to detect the presence of low flow distal to occluded or highly stenotic segments. Power Doppler imaging (PDI) which allows a direct representation of the geometry of the blood flow is a new alternative since it offers several advantages over duplex scanning and color flow imaging: it is characterized by a greater sensitivity to flow, is aliasing free, nearly Doppler angle independent, and little affected by the flow rate (2). PDI has been mainly used for imaging small, low-flow vessels associated with renal, musculoskelatal, fetal and cerebral perfusion (3). This technique has, however, the potential for being applied to larger vessels. Further experimental and clinical studies are required to clearly validate its potential to quantify arterial stenosis. For instance, it is known that the ultrasound backscattering properties strongly depend on the flow characteristics and spatial arrangement of moving scatterers. Quantitative validation of PDI with blood is thus essential since turbulence and red cell aggregation affect the scatterer sizes and the correlation between red cells, and consequently the Doppler backscattered power from blood.
KeywordsFlow Area Area Reduction Doppler Power Duplex Scanning Stenotic Segment
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