Densitometry in ultrasound refers to measurement of the gray level intensity of an image region. Ultrasound image gray levels usually have non-linear relationships to the echo amplitude that makes densitometry not suitable for evaluation of contrast images.

Doppler ultrasound is a medical imaging technique for calculating the relative velocity between two points by measuring the frequency shift of a sound wave transmitted from one point to the other, based on the Doppler effect. Continuous or pulsed Doppler is frequently used to examine cardiovascular blood flow. The combination of routine 2D-mode and Doppler ultrasound allows a complete evaluation of the heart's anatomy and function (including the fetal heart). See also Doppler Fluximetry in Pregnancy.
Doppler ultrasound depends on the fact that if a moving object reflects the ultrasound waves, the echo frequencies are changed. A higher frequency is created if the object is moving toward the probe//transducer and a lower frequency if it is moving away from it. How much the frequency is changed depends upon how fast the object is moving. Doppler ultrasound shows the different rates of blood flow in different colors on a monitor in real time.
The major Doppler parameters are the peak systolic velocity and the end-diastolic velocity. The peak systolic velocity ratio compensates the variability between different patients and instrumentations.

Different Doppler and duplex techniques:

E-Z-EM, Inc. was headquartered in New York and developed, manufactured and marketed diagnostic imaging products used by radiologists like the MRI bowel marker Gadolite® Oral Suspension.
In addition to medical diagnostics systems, the company's products included interventional devices, such as biopsy needles. E-Z-EM was also a third-party contract manufacturer of contrast media.

Bracco Diagnostics, Inc., the US-based subsidiary of Bracco Imaging S.p.A. and part of the Bracco Group, announced in Oct. 2007 that it has entered into a merger agreement to acquire E-Z-EM, Inc. (NASDAQ: EZEM). Bracco Imaging's portfolio offering has been broadened with completion of the acquisition in 2008.

Ultrasound enhancement is the increase in reflection amplitude from objects that lie behind a weakly attenuating structure. Contrast agent particles enhance the reflectivity of blood.
The enhancement artifact may occur in structures below a cyst.

From Biosound Esaote, Inc.;
'The new, more powerful Megas ES is a technologically advanced ultrasound system in a highly portable package. Offering options such as CnTI™ software to support contrast agents and DICOM connectivity and storage for film-less, tape-less diagnostic services, Megas ES is the practical alternative for today's demanding diagnostic needs.'

Specifications for this system will be available soon.