Acousto-mechanical and thermal properties of clotted blood

Abstract

The efficacy of ultrasound-assisted thrombolysis as an adjunct treatment of ischemic stroke is being widely investigated. To determine the role of ultrasound hyperthermia in the process of blood clot disruption, the acousto-mechanical and thermal properties of clotted blood were measured in vitro, namely, density, speed of sound, frequency-dependent attenuation, specific heat, and thermal conductivity. The amplitude coefficient of attenuation of the clots was determined for 120 kHz, 1.0 MHz, and 3.5 MHz ultrasound at room temperature (20 +/- 2 degrees C). The attenuation coefficient ranged from 0.10 to 0.30 Np/cm in porcine clots and from 0.09 to 0.23 Np/cm in human clots. The experimentally determined values of specific heat and thermal conductivity for porcine clotted blood are (3.2 +/- 0.5) x 10(3) J/kg x K and 0.55 +/- 0.13 W/m x K, respectively, and for human clotted blood are (3.5 +/- 0.8) x 10(3) J/kg x K and 0.59 +/- 0.11 W/m x K, respectively. Measurements of the acousto-mechanical and thermal properties of clotted blood can be helpful in theoretical modeling of ultrasound hyperthermia in ultrasound-assisted thrombolysis and other high-intensity focused ultrasound applications.

Characterization of blood clot viscoelasticity by dynamic ultrasound elastography and modeling of the rheological behavior

“…where G(o) is the complex shear modulus, UyðxÞ is the wave amplitude Uyðx,tÞ ¼ UyðxÞe iot and r is the material density assumed constant at 1080 kg/m 2 (Nahirnyak et al, 2006). Because harmonic plane shear waves were used, the time dependence can be omitted for simplification.…”

A new effective thermal conductivity model for a bio-nanofluid (blood with nanoparticle Al2O3)

“…Therefore, for verification purposes, we compare our calculated blood cells thermal conductivity with red blood cells thermal conductivity reported in the experimental study [19]. Fig.…”

“…(Base fluid is the mixture of plasma and Al 2 O 3 nanoparticles and blood cells are treated as microparticles.) Here the thermal conductivity of the blood cell was evaluated by different methods, and the experimental value provided in [19] was also used. Fig.…”

Large deforming buoyant embolus passing through a stenotic common carotid artery: A computational simulation

“…Moreover, the great deformation of embolus was a big limitation which restricted us to model more severe situations of thromboembolism. It is valuable to note that there are also other reported nonlinear material properties for thrombus by Xie et al (2005) as well as other researchers (Gennisson et al, 2006a;Nahirnyak et al, 2006;Riha et al, 1999) that is worth to be implemented to numerical models using our presented approach. We did not assume pulsatile flow conditions in our study due to the reason that in our simulations, thromboembolism took place in a short period of time which was much less than duration of a heartbeat.…”