Which MRI contrast agent is commonly used due to its paramagnetic properties?

Gadolinium is commonly used as an MRI contrast agent because of its paramagnetic properties. Paramagnetic substances have unpaired electrons, which allow them to influence the magnetic field during MRI scanning. When gadolinium is used as a contrast agent, it enhances the contrast between different tissues and blood vessels, making it easier to identify abnormalities.

Gadolinium significantly affects the relaxation times of nearby hydrogen nuclei in the body, leading to increased signal intensity in the areas where it accumulates. This makes it particularly useful in highlighting tumors, inflammation, and other pathologies that may not be clearly visible on standard MRI images without contrast.

The other substances listed do not exhibit the same properties suitable for MRI contrast enhancement. For instance, iron oxide is used in specific applications like imaging of certain types of lesions or liver imaging, but it does not have the same widespread application as gadolinium in routine MR imaging. Barium sulfate is primarily used for gastrointestinal imaging in X-ray studies and has no application in MRI as a contrast agent. Iohexol, on the other hand, is an iodinated contrast agent used mainly in computed tomography (CT) scans, not MRI. Thus, gadolinium stands out as the standard choice for enhancing MRI imaging due to its