contrast(redirected from positive contrast)
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Related to positive contrast: negative contrast
contrastImaging An MRI term for the relative difference of signal intensities in two adjacent regions of an image. Image contrast heavily depends on the chosen imaging technique (i.e., TE, TR, TI), and reflects such parameters as proton density and T1 or T2 relaxation times.
Contrast (agent, medium)
brightness contrast The enhanced apparent darkening of an area when viewed near, or following a lighter stimulus (or lightening, near or after a darker stimulus).
colour contrast 1. A difference in the appearance of surfaces based on hue or saturation. 2. The enhanced difference in the colour of two surfaces induced by their proximity (simultaneous colour contrast) or successive stimulation (successive colour contrast). The appearance of the smaller area shifts towards the complementary colour of the surround or background. Example: a yellow area appears reddish when surrounded by a green background.
contrast sensitivity function See contrast sensitivity function.
contrast sensitivity test See contrast sensitivity chart; contrast sensitivity.
simultaneous contrast A difference in the appearance of two adjacent areas occurring at the same time.
successive contrast A difference in the appearance of stimuli following each other.
contrast threshold See contrast sensitivity; differential threshold.
Patient discussion about contrast
Q. Has anyone had an allergic reaction to gadolinium dye, MRI contrast agents, I have had a severe reaction. I would like to know the long term effects of this dye. And if anyone else has had or heard of problems and reactions to it. Please answer me. Thank you