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P. Pfundner, U. Cobet, J. Hofmann, K. Bauer:
"Quantitative Bestimmung der Erythrozytenaggregation mit Ultraschalldoppler";
Vortrag: QUANSON 98 Quantitative Sonographie in Klinik und Forschung, Halle/Saale; 19.03.1998 - 21.03.1998.

Several methods - direct and indirect - exist to quantify the rheology of blood: e.g. viscosity measurement represents a direct method, whereas quantification of the aggregation kinetics is an indirect method. For aggregometry light transmission devices are mainly used, as well as ultrasonic devices, which are based on the scattering properties of blood. When choosing CW ultrasound and evaluating the Doppler shift, high accuracy over a wide measurement range can be achieved with an additional possibility to correlate aggregation phenomena with shear forces.
The flow arrangement consists of a modified controllable peristaltic pump. Two to three milliliters of blood are necessary to fill the system. The Doppler shifted signal scattered from the erythrocytes, which is induced by a 10 MHz ultrasound wave, is recorded. As a result of the following signal postprocessing the scattering intensity in dependence of the mean shear rate in the test tube is achieved.
In this project we tried to evaluate the usefulness of the ultrasound method under the assumption of an easy to use system. For this purpose the precision of the measured data was investigated, the dependence on hematocrit was measured and compared to existent theory and an evaluation of specimen with standardized aggregation was performed. More than 350 human blood samples were analyzed in order to check relationship between the aggregation of red cells and various parameters such as plasma proteins, sedimentation rates, age or gender.