Medical ultrasound
A contrast medium for medical ultrasonography is a formulation of encapsulated gaseous microbubbles to increase echogenicity of blood, discovered by Dr Raymond Gramiak in 1968 and named contrast-enhanced ultrasound. This contrast medical imaging modality is clinically used throughout the world, in particular for echocardiography in the United States and for ultrasound radiology in Europe and Asia.
Medical ultrasound
The first demonstration of color Doppler was by Geoff Stevenson, who was involved in the early developments and medical use of Doppler shifted ultrasonic energy.