[Abnormal intracavitary dynamic echoes. I. An in vitro study].

We performed in vitro experiments to study blood echodensity during stasis or slow flow rate. Quantitative and qualitative evaluation of water, blood, plasma and washed red cells at different dilutions (1:5, 1:10, 1:20, 1:50) were made. Two 2D echo equipments (2,5,-3,5 Mhz) were utilized. No echoes were observed in water and plasma. Blood was strongly echogenic. A progressive reduction of the echodensity of washed red cells was observed with increasing dilution. We conclude that scattering of ultrasound by blood, during stasis or slow flow, can be detected utilizing commercially available echocardiographic systems; red cells may represent the scattering agent.