FIG. 4.
Ultrasonic imaging method to measure erythrocyte aggregation. (a) Schematic diagram of the ultrasound imaging system. Blood is delivered into the vascular phantom with an inner diameter of 1 mm. An acoustic absorber is placed in the bottom of the phantom to minimize ultrasound artifacts. (b) Variation of flow rate (Q) estimated based on the results of speckle image velocimetry measurement. Typical velocity fields at specific times of [(a)–(c) t = 0, 2.5, and 5 s]. (c) Temporal variation of the echogenicity distribution measured along the radial direction. Temporal variations of the mean echogenicity (e) in the whole tube with respect to (d) hematocrit (Ht) and (e) dextran concentration (CDextran) at Ht = 40%. (f) Quantitative evaluation of aggregation index (AIEcho) according to CDextran. An explanation depicting AIEcho using the data (CDextran = 0.03%) is included. Each data set indicates the mean value and standard deviation evaluated from three test samples.