High sensitivity estimation of red blood cell aggregation with ultrasonic peak frequency

A novel technique for detecting the peak frequency of an ultrasonic reflection spectrum was proposed, aimed at enhancing the sensitivity and accuracy of estimating the aggregation size of red blood cells (RBCs). Peak frequencies for stagnant and running suspensions prepared with monodispersed industrial particles that were used to mimic aggregated RBCs were acquired. As a result, the relationships between the particle diameters and the peak frequencies, which were independent of the material of the particles, flow rate, and the viscosity of the suspension, were obtained. For bidisperse samples, i.e., mixtures of two different sized particles, quantitative relationships corresponding to changes in the mixing ratio were observed.