Ultrasonic multi-channel method for investigation of non-stationary biologic liquids

Abstract

In this paper we present a multi-channel ultrasonic method enabling to reveal regularities of a blood clotting both in time and space domains. Ultrasound velocity variations are measured simultaneously in a few parallel channels thus blood clotting process is monitored in different but closely located spatial domains.

Experiments reveal that in non-stationary liquid medium structure of which varies in volume and in the time domain (blood clotting, erythrocyte sedimentation, chemical reaction of polymerization, etc.) the results of ultrasonic measurements depend on orientation of the ultrasonic wave propagation direction with respect to horizon. In such cases the measurement results can be compared only at the same experimental conditions. Moreover, in a horizontal position measured ultrasound velocities depend also on axial orientation of the chamber, i.e. which channel is on the top. The proposed multi-channel measurement method enables to investigate spatial non-uniformities and variations in the time domain occurring in biologic liquids.

Experiments were provided with a small < 1 ml volume four channel chamber in a throw-transmission mode, frequency was 5 MHz. An axial symmetry of the channels was exploited, hence the diffraction effects in all channels were identical.