Design and development of a new ultrasonic doppler technique for estimation of the aggregation of red blood cells

Abstract Aggregation of red blood cells (RBCs) is one of the principal hemorheological factors which plays an important role in capillary circulation. In order to study the RBC's aggregation, an ultrasound Doppler in-vitro technique, using pulsed wave monoelement pencil 4 MHz probes, has been designed. An hydraulic pump system has been implemented, establishing a laminar blood flow profile into a rectangular cross-section plexiglass tube. Adding dextrans to blood samples, red blood cells aggregation has been achieved and observed for various hematocrit values. Both the emitted and the backscattered signals, were driven to a system containing a multi-channel digital oscilloscope – of high sampling rate and processing capabilities – and a powerful PC with a high acquisition A/D card and special control software. Quantitative detection and measurement of the aggregation phenomenon can be achieved according to the experimental conditions and parameters used.