The term hyperechogenic or hyperechoic is used if there are many internal echoes. Hyperechoic tissues appear bright in ultrasound imaging. Tendons are hyperechoic because of the fibrillar pattern. Ligaments appear hyperechoic when the beam is perpendicular to the tissue. Peripheral nerves are hyperechoic relative to muscle. Liver angiomas, tumor cells, blood vessels, fibrosis, and liver steatosis appear diffuse hyperechoic.

Solid regions have internal ultrasound echoes and are classified as echo poor, hypoechoic or hypoechogenic if there are few internal echoes. Hypoechoic structures appear dark in ultrasound imaging, more homogeneous structures are darker than heterogeneous.
Soft atherosclerotic plaque, liver adenoma or FNH appear with a nodular hypoechogenicity. As metastases close the blood vessels they infiltrate, tumor tissues become hypoechogenic after injection of contrast agent. Muscle appears relatively hypoechoic to tendon fibers, also articular hyaline cartilage appears hypoechoic.

Founded in 1991, ImaRx Pharmaceutical Corp. designs, develops and markets pharmaceuticals for medical imaging (MRI, ultrasound and computed tomography) for the radiological imaging industry.
ImaRx Pharmaceutical Corp., announced 1999 that it has been acquired by E.I DuPont de Nemours & Co., Inc. The terms of the acquisition provide a royalty-free licensing arrangement with a newly-formed company, ImaRx LLC ('LLC'), to pursue and develop new products and technologies for drug and gene delivery independent from DuPont. Yamanouchi Pharmaceutical Co. Ltd., ImaRx' licensee for Asian territories for this product, will continue to develop the product in Asia as DuPont's licensee. ImaRx LLC will have ownership of all other targeted and therapeutic products previously owned by ImaRx, including imaging products outside of diagnostic ultrasound imaging and two other imaging products, SonoRx® and LumenHance®, which are both FDA approved and licensed to BRACCO Diagnostics.
See also Lantheus Medical Imaging and Definity®.

Ultrasound Contrast Agents:

The perfect image quality is dependent on some assumptions of the propagation of ultrasound waves in tissues after generating in an imaging system. These assumptions are important for the developing of optimal ultrasound imaging systems.
A lot of steps can be taken to prevent artifacts and to improve image quality, for example beamforming is used to focus the ultrasound beam, and contrast agents decrease the reflectivity of the undesired interfaces or increase the backscattered echoes from the desired regions.

See also Coded Excitation, Validation and Refraction Artifact, Q-Value, Ultrasound Phantom, Dead Zone, Narrow Bandwidth.

Imagent® is an injectable suspension for intravenous administration during a sonogram. This diagnostic contrast agent for enhancement of ultrasound images contains perflexane lipid microspheres. Imagent® US is indicated in the assessment of heart function and perfusion, as well as the detection of tumors and blood flow abnormalities by using gray scale, color Doppler, and harmonic ultrasound imaging techniques.
During the course of its development, the brand name for this product has changed from Imagent to Imavist (between August 2000 and March 2002) back to Imagent. The manufacturer's 06/03/02 press release announcing FDA approval refers to the product as 'Imagent (formerly Imavist),' and the approval notice and monograph posted at the FDA site refers to the product as Imagent.
Jointly developed by Alliance Pharmaceutical Corp and Bayer Schering Pharma AG (Germany). Source: PR Newswire - 10/10/96, 03/31/98, 10/13/99, 03/13/01, 10/08/01; FDA approvals - 05/31/02; Alliance Pharmaceutical press release - 06/03/02.
Currently the production of Imagent® is discontinued.