|Factors affecting the appearance|
As fluoroscopy images are live images using x-rays, the same factors which affect the appearance of radiographs will influence the fluoroscopic image, such as density, thickness and shape. Click here if you need to review these factors.
The main difference in the appearance of radiographs vs. fluoroscopic images is in the use of contrast. Contrast agents are almost always used to highlight areas of interest and improve the diagnostic yield of the study.
Contrast agents can be placed in many different cavities of the body to allow them to be seen, including blood vessels, GI tract, biliary system, CNS, joints, uterus, and the urinary tract. What contrast agent is used will affect the appearance as well. The next few pages show a few examples of fluoroscopy and contrast agent appearance.
Importantly, fluoroscopic images are digital images which can be displayed such that dense structures appear white, like radiographs, or the images can be inverted such that dense structures appear black.