Decimation is the reduction of data at the digitized signal. Fewer samples are used to represent the detected signal. The opposite process is called interpolation, more samples are added.

See also Digital Radiography, and Digital Subtraction Angiography.

Digital images can be manipulated for evaluation in various ways. Post-processing includes: Subtraction, addition, rotation, inversion, multiplanar reconstruction (MPR), maximum intensity projection (MIP), etc.
Subtraction is particularly useful in contrast enhanced examinations. The pre contrast images are subtracted from the images after an injection of contrast agents (sometimes also called dye) for better tumor detection. See also Contrast Enhanced Computed Tomography, Digital Subtraction Angiography and Active Zone.

Hexabrix is an ionic dimer contrast medium. Intravascular injection of Hexabrix enhances those vessels in the path of the flow, permitting radiographic visualization of the internal structures of the human body until significant hemodilution occurs. The contrast agent is transported through the circulatory system to the kidneys and is excreted unchanged in the urine. Hexabrix is used primarily for peripheral arteriography