Ultrasound characterization of red blood cell aggregation with intervening attenuating tissue-mimicking phantoms.
The analysis of the ultrasonic frequency-dependent backscatter coefficient of aggregating red blood cells reveals information about blood structural properties. The difficulty in applying this technique in vivo is due to the frequency-dependent attenuation caused by intervening tissue layers that distorts the spectral content of signals backscattered by blood. An optimization method is proposed to simultaneously estimate tissue attenuation and blood structure properties, and was termed the structure factor size and attenuation estimator (SFSAE). An ultrasound scanner equipped with a wide-band 25 MHz probe was used to insonify porcine blood sheared in both Couette and tubular flow devices. Since skin is one of the most attenuating tissue layers during in vivo scanning, four skin-mimicking phantoms with different attenuation coefficients were introduced between the transducer and the blood flow. The SFSAE gave estimates with relative errors below 25% for attenuations between 0.115 and 0.411 dBMHz and kR<2.08 (k being the wave number and R the aggregate radius). The SFSAE can be useful to examine in vivo and in situ abnormal blood conditions suspected to promote pathophysiological cardiovascular consequences.
Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center, Pavillon JA de Seve Room Y-1619, 2099 Alexandre de Seve, Montreal, Quebec H2L 2W5, Canada.
Emilie
E
Franceschini
François T H
FT
Yu
François
F
Destrempes
Guy
G
Cloutier
D000465:Algorithms; D000818:Animals; D004903:Erythrocyte Aggregation; D004912:Erythrocytes / Q000000981:diagnostic imaging* / Q000502:physiology*; D019047:Phantoms, Imaging; D012815:Signal Processing, Computer-Assisted; D012867:Skin / Q000000981:diagnostic imaging; D012879:Skin Physiological Phenomena; D013552:Swine; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*