A new ultrasonic technique for quantifying blood echogenicity.

The echogenicity of blood varies with the conditions of flow. This study introduces a new technique for quantifying blood echogenicity and includes digitalization of the signal from an A-mode ultrasound scanner, integration, subtraction, and computer analysis of the signal. Shear rate (directly proportional to velocity) had an inverse relationship to the blood echogenicity. Hemodilution with Ringer's solution and with low-molecular-weight dextran 1 decreased blood echogenicity, whereas the addition of a macromolecular protein (dextran 70) increased blood echogenicity. This technique makes possible a quantitative analysis of the factors affecting blood echogenicity.