(CAI) Color amplitude imaging shows the amplitude of the Doppler signal from moving blood flow. CAI is an ultrasound technique with increased dynamic range and flow sensitivity. The sensitivity of Doppler ultrasound increases markedly in conjunction with the use of vascular contrast agents.

See also Amplitude Map, Amplitude Indicator.

(CDI) Color Doppler imaging depicts the mean frequency shifts of the Doppler signal. Color [colour, Brit.] Doppler imaging is a method for visualizing direction and velocity of movement, such as of blood flow within the cardiac chambers or blood vessels. The flow direction and velocity information gathered by Doppler ultrasonography is color coded onto a gray scale cross-sectional image. The sensitivity of Doppler ultrasound is increased in conjunction with the use of vascular contrast agents.
Direction and blood flow velocity are coded as colors and shades:
Red - flow coming nearer to the probe.
Blue - flow coming away of the probe.

See also Bi-directional Illumination, Color Map.

(CHI) Contrast harmonic imaging is an ultrasound technique to improve the measurement of blood perfusion or capillary blood flow. Based on the nonlinear properties of contrast agents, CHI transmits at the fundamental frequency but receives at the second harmonic. Contrast enhanced echo signals contain significant energy components at higher harmonics (bubbles acts as harmonic oscillators), while tissue echoes do not. Caused by that contrast signal can be separated from tissue echoes by the characteristic signal.
In combination with the pulse inversion technique, CHI promises very high contrast agent sensitivity with high spatial resolution.

See also Ultrasound Contrast Agent Safety and Hemoglobin.

A contrast medium (or contrast agent) is a chemical substance applied to the anatomical or functional region being imaged, to increase the differences between different tissues or between normal and abnormal tissue.
The chemical composition of the contrast media determines the specific usage. The intention in the development of ultrasound contrast media is a high contrast between blood and tissues in different organs or even tumors.

See also ultrasound contrast agents, the info sheet gives an overview and more in-depth information about different types of ultrasound contrast medium.

From Bayer Schering Pharma AG:
Echovist-200® was an effectively one-pass-only contrast medium for contrast sonography and Doppler-echocardiographic examinations for the detection, exclusion or follow-up of pathological states leading to hemodynamic changes. Because of the short intravascular life of the microparticles and microbubbles, transit through the pulmonary circulation is unusual. In cardiac evaluations Echovist-200® has been replaced by newer ultrasound contrast agents (USCA), therefore the manufacturing was discontinued.
Another range of echo contrast application is the female genital tract, in particular for the demonstration or exclusion of acquired or congenital changes of the uterine cavity and for the visualization of the Fallopian tubes and investigation of their patency.
1 g Echovist-200 granules contain 1 g D-galactose microparticles. 1 ml aqueous solution for production of the suspension contains 200 mg D-galactose.
Brand names in other countries: Ecovist.