An ultrasonic method for detection of fluid properties in the paranasal sinuses

• We propose a method for detection of the degree of infection in the paranasal sinuses utilizing a previously published method whereby the viscosity in a sealed container may be measured using an ultrasound Doppler method. As ultrasound propagates in a liquid medium, due to attenuation, the resulting pressure gradient will cause the liquid to move in the propagation direction - the wellknown effect of acoustic streaming. The streaming velocity will, for a given acoustic output, be proportional to the viscosity of the fluid. In this study, we verify that acoustic streaming can be induced in an anthropomorphic sinus phantom cast from a human cranium. The sinus phantom was made from agar with added graphite providing sound attenuation prior to the sinus cavity corresponding to an in vivo situation. A number of water-glycerol solutions with scattering particles, were prepared to mimic a clinically interesting range of viscosities (7-47 mPas). Using a 4.2 MHz continuous wave Doppler probe, clearly detectable Doppler shifts in the range of 6.5 to 20 Hz were recorded. A linear relationship was found between the Doppler shifts and 1/viscosity (R2=0.94, corrected for the square-law dependence of sound speed variation due to varying glycerol concentration)

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Oto-rhino-laryngologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Otorhinolaryngology (hsv//eng)

Nyckelord

water-glycerol solution

continuous wave Doppler probe

scattering particles

4.2 MHz

Doppler shifts

6.5 to 20 Hz

sinus cavity

sound attenuation

graphite

agar

human cranium

anthropomorphic sinus phantom

streaming velocity

acoustic streaming effect

fluid viscosity measurement

infection detection

paranasal sinuses

ultrasonic Doppler method

fluid property detection

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