Contrast Agents

MRI

Contrast Agents are drugs used during magnetic resonance imaging. They help us to improve the ability to diagnose certain diseases, especially those of the brain and spine. Some contrasts are useful in diagnosing diseases of the bones, joints, liver, breast, and soft tissues. They also help us to rule out some diseases. The use of contrast media does not necessarily mean that an abnormality has already been identified.

The decision to use contrast media is made by the radiologist. However, it is recommended to discuss the administration with the referring clinician, especially in cases that its clinical necessity is questionable. Patients are usually screened for any medical history that precludes the use of a contrast agent, such as allergies, asthma, rash or hemolytic anemia.

Blood tests to check kidney function are not usually required, as the contrast media used in MRI scans do not cause kidney damage.

Computed Tomography

On a CT scan the images are produced on a scale of white to black. Sometimes, however, some structures are depicted in similar contrast, making it difficult to distinguish between the two areas. Contrast agents help to overcome this problem as they are absorbed and improve the contrast between various structures and vessels under investigation.

Intravenous contrast is based on iodine and there is always the risk of anaphylaxis and affect renal function. Therefore, blood tests for urea and creatinine are necessary before the administration. As with MRI, the final decision to administer the contrast medium is made by the radiologist.