What is the Contrast Material for CT and MR scans, and is it Safe?

The field of medical imaging has advanced exponentially since the discovery of the x-ray by Wilhelm Röntgen in 1895. The x-rays were put to medical use even before the dangers of radiation were fully understood. Much in the same way, many other medical procedures were practiced before they were fully understood.  This is, understandably, the main reason behind the misconceptions behind medical imaging, specifically CT and MRI scans’ use of a contrast agent.  But medicine has caught up quite well, and today’s scans are as safe as you can get.

Contrast mediums or materials, as used in medical imaging practices, are substances applied to the patient to increase the contrast of bodily structures or fluids during the imaging process. By enhancing the visibility of the inner body, contrast materials help identify and/or prevent serious medical issues better than imaging of the past ever could.

The materials are typically injected into the body, which causes concern for patients due to outdated stigma surrounding the two types of materials used.

CT scans, or computed tomography imaging, is an x-ray based imaging technique that creates a three dimensional “slice” image of the patient.. These days, intravascular contrast agents are iodine based, due to its relatively harmless interaction with the body.

MRI scans, or magnetic resonance imaging, typically use a contrast agent that is gadolinium-based. Gadolinium alters the relaxation time of atoms that make up body tissues. MRI scans expose the body to a strong magnetic field, followed by a radiofrequency pulse that causes atoms to spin and then relax. The relaxing process emits energy, which is then picked up by the scanner. Put simply, the contrast agent alters the way the scanner affects you, creating a contrast in the image it produces.

These highly technical explanations of the two different types of contrast materials used in medical imaging may sound a little frightening, but patients need not worry. Medicine as a whole has gotten much safer over the years. Contrast materials wouldn’t be in use as much as they are today if they weren’t safe enough.

Contrast mediums do, however, carry a small risk with use. Reactions may occur, ranging from mild allergic reactions to severe.  Death may occur, with the odds being about 0.9 per 100,000 cases (roughly equal to death by lightning). Certain risk factors do exist that can point to the possibility of a bad reaction to the contrast materials. Medical imaging professionals know what to look for in these patients, greatly reducing the occurrences of adverse side effects of the materials.

Here at Doctors Imaging, patient safety is always our top priority. We’re radiologists concerned about your safety and quality patient care. If you ever have any questions about our methods, please just contact us and we’re happy to discuss.

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