What is contrast and non-contrast scans in radiology?

Contrast materials, also called contrast agents or contrast media, are used to improve pictures of the inside of the body produced by x-rays, computed tomography (CT), magnetic resonance (MR) imaging, and ultrasound. Often,contrast materials allow the radiologist to distinguish normal from abnormal conditions.

URL: https://www.radiologyinfo.org/en/pdf/safety-contrast.pdf