What substance is commonly used as a contrast agent in MRI?

Gadolinium-based compounds are the commonly used contrast agents in MRI due to their unique magnetic properties that enhance the visibility of internal body structures during imaging. Gadolinium is a paramagnetic element, meaning it has unpaired electrons that contribute to a greater signal contrast when placed in a magnetic field, as found in MRI machines. This improvement in contrast is particularly useful when differentiating between normal and abnormal tissues, identifying tumors, lesions, or areas of inflammation.

The use of gadolinium-based contrast agents allows radiologists to obtain clearer and more detailed images, which aids in accurate diagnosis and treatment planning. These agents are generally safe for patients, although there can be precautions for those with kidney issues due to the risk of nephrogenic systemic fibrosis in rare cases.

In contrast, sodium chloride is commonly used in other medical applications but not as an MRI contrast agent. Iohexol and barium sulfate are specifically used for other types of imaging techniques, such as CT scans or gastrointestinal studies, rather than MRI.