Ultrasound may do more than produce images. Researchers at Kaunas University of Technology (KTU) report that low-frequency ultrasound waves directly influence how blood flows, acting on the red blood cells themselves rather than simply bouncing off them to create a picture.
The detail that caught the team off guard was the direction of the effect. Different frequencies did not just produce more or less of the same response - they produced opposite ones. Some frequencies encouraged red blood cells to gather into clusters, while others broke those clusters apart into single cells.
That matters because red blood cells, or erythrocytes, naturally form reversible clumps called aggregates, and the degree of clumping helps set blood viscosity, which in turn shapes circulation and how efficiently oxygen is carried through the body. According to the researchers, when high-frequency ultrasound drives erythrocytes together, viscosity climbs, blood pressure and pulse can rise, and oxygen exchange becomes less efficient.
The KTU team frames this as a possible route toward supporting treatment for cardiovascular disease, Alzheimer's disease and diabetes, with the longer-term hope of reducing reliance on invasive procedures or drugs. That remains a prospect rather than a therapy: the work so far establishes that ultrasound frequency can steer red blood cell behavior, not that any clinical benefit has been demonstrated in patients.