enhancement

1. The act of augmenting. 2. In immunology, the prolongation of a process or event by suppressing an opposing process.

- acoustic e. a manifestation of increased echo amplitude returning from regions beyond an object, such as a fluid-filled cyst, which causes little or no attenuation of the ultrasound beam. Cf.:acoustic shadow.

- contrast e. the intravenous administration of water-soluble iodinated contrast material, which increases the CT number of the vascular pool, as well as some lesions (particularly in the brain), due to abnormal leakage into the interstitium; the property of showing increased radiopacity from concentration of contrast medium.

- edge e. using analogue or digital image processing to increase the contrast of each interface; equivalent to using a high-pass filter.

- immunologic e. SYN: immunoenhancement.

- ring e. in computed tomography, when a bright circle appears on an image made after injection of contrast medium, characteristic of localization of the contrast in the wall of an abscess.

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en·hance·ment (en-hansґmənt) 1. an increase or promotion of something. 2. prolonged survival of tumor cells in animals previously immunized with antigens of the tumor owing to the presence of “enhancing” or “facilitating” antibodies that prevent an immune response against these antigens; called also immunologic enhancement.