The transition phrase “in contrast” is tantamount to “different from” which is used to express dissimilarity of entities or ideas This means that when one thing is “in contrast” to another, then logic suggests that there is no way for these two to share the same characteristics.

You might need contrast when you are having an X-ray, CT, MRI, or ultrasound exam. It can be an iodine-based material, barium-s ulfate, gadolinium, or saline and air mixture that can be swallowed or injected intravenously. Contrast distinguishes, or “contrasts,” between organs, tissues, bones, or blood vessels during your imaging exam.

MRI with contrast should be ordered when a more detailed view of organ structure and function is needed; a detailed view of inflammation, analysis or diagnosis of a reported tumor, or to analyze blood flow and supply.

The decision to use contrast is based on whether the aim of the procedure is: Diagnostic (to identify disease) Interventional (to aid with the management of a known condition) Their use is directed in part by the American College of Radiology (ACR) Appropriateness Criteria.