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MRI VS. CT Scans: What is the Difference?

Whether you're going for a routine operation or you're facing long-lasting treatment, you may find yourself undergoing diagnostic procedures.

Many doctors like to use different imaging “modalities” or methods in order to diagnose or treat patients. In medical imaging, MRI, X-ray and CT scans are some of the options your medical professionals will consider in order to see what's happening inside their patient's body.

However, as a patient yourself, you might be wondering what the difference between an MRI, an X-ray, and a CT scan is. Knowing more about each one and how they work may make you feel more comfortable about your care.

CT scans use X-ray beams, and MRIs don't

A CT scan can look inside your body by using X-ray beams. Unlike normal X-rays, these beams move through a specific area in fine slices. Depending on the nature of the machine, they provide various levels of detail regarding tumors, fractures, bleeding, and more.

In contrast, MRI scans use magnetic resonance imaging to bounce magnetic waves off the hydrogen atoms in your body. While doing this usually takes longer, it also provides greater levels of detail.

As a CT scan uses X-ray beams, it's excellent for looking at dense areas of your body. But, when it comes to soft tissues and blood flow, it doesn't always prove as useful. As such, your doctors may opt for an MRI because they feel it will provide a clearer insight into your condition.

The magnetic beams an MRI scanner uses can make it easier to differentiate between various areas of the body. With a clearer view of what's happening inside you, they can guide procedures, provide a clearer analysis in situations such as post-cancer treatment, and aid with various diagnoses such as cancer staging.

MRI scans usually last longer than CTs

When a CT scan takes place, the machine moves quickly across one area of the body. As it does so, it takes pictures in the form of slices, which eventually create a picture your doctor can use to look for abnormalities.

The way a CT scanner operates often means it's quicker than an MRI, which makes it more accessible in emergency settings. CT scanners also have a different shape, which some describe as a donut.

In comparison, many MRI scanners are shaped like a long tube, which your entire body enters. This can cause feelings of anxiety in those prone to claustrophobia.

While CT scans, X-rays and MRI machines all make noise, MRIs often produce humming, clicking and louder noises that can increase the anxiety level in certain patients.

CTs involve radiation exposure, whereas MRIs do not

When undergoing any imaging technique, you might worry about ionizing radiation. CT scans act like multiple X-rays that take place over a short period.

While the radiation exposure is still low and considered safe, it’s advisable to minimize exposure to radiation whenever possible.

In contrast, an MRI does not use any ionizing radiation at all. Because of this, they may be safer for children and pregnant or nursing women.

The contrast agents your doctor uses will vary

Not everyone who undergoes a CT scan or an MRI will need a contrast agent. However, the contrast dyes used by CT scans and MRIs are different.

Of course, you should discuss any questions about the differences between medical imaging approaches with your physician.

With a strong insight into your medical background, they can determine whether an MRI, X-ray, or a CT scan will work better for you.