(DSA) Digital subtraction angiography is a radiographic imaging technique to visualize the blood vessels in the human body. DSA images are produced by the (computer) subtraction of pre-contrast images (the mask) from images after introduction of a contrast medium. Subtracting background structures and enhancing the contrast provides the visualization of blood vessels in a bony or dense soft tissue environment. The images are produced in real time, as the contrast agent is injected into the blood vessels.

Angiography means the imaging of veins and arteries. The examination is called angiogram.

See also CT Angiography, Coronary Angiogram, Digital Subtraction Angiography, Venography and Magnetic Resonance Angiography MRA, Contrast Media Injector, Single-Head CT Power Injector.

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.

Optiray® is a radiographic contrast agent. Optiray® is available in concentrations from 160 to 350 mg/mL organically bound iodine. Optiray® solutions have osmolalities 1.2 to 2.8 times that of plasma (285 mOsm/kg water).
Optiray® 160 is recommended for intraarterial digital subtraction angiography (IA-DSA).
See also Single-Head Contrast Media Injector, Dual-Head CT Power Injector, Syringeless CT Power Injector.

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.