Hematocrit evaluation based on ultrasonic estimations of shear rate and viscosity in blood flow

Blood viscosity is a promising index for detecting blood abnormality such as thrombosis. However, due to the non-Newtonian property of whole blood, unique evaluations of blood property might be difficult. In this study, the hematocrit (HCT) is evaluated noninvasively based on the ultrasonic estimation of shear rate-viscosity (SV) curve, which is uniquely formed by the HCT. In vivo measurements for healthy subjects revealed the proposed method provided reasonable HCT estimations. As a practical application of this method, the quantitative shear stress estimation in the flow-mediated dilation measurement was also investigated.