MRI vs. CT Scans: Understanding the Difference

February 16, 2023 – 4 min read

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MRI vs. CT Scans: Understanding the Difference

If you are injured or have concerning symptoms, your doctor may order imaging tests to get a better idea of what’s wrong. MRI scans and CT scans are two common options. Although both take highly detailed images of internal structures, they each have their strengths, so it helps to understand why your doctor chooses one over the other.

How CT scans work

CT, or computed tomography, uses specialized X-rays to produce precise images, also called “slices,” of the internal structures of your body. During a CT scan, the radiologist can review the images individually or, using a computer, combine to create 3D images. CT scans provide more detail than X-rays, giving your doctor the most accurate insight to make a diagnosis, suggest treatments, or determine the stage of cancer.

When you have a CT scan, you lie inside a donut-shaped machine while a scanner spins around your body. Each rotation produces a single slice. The scan is over in a matter of minutes, making them faster than the average MRI scan.

CT scans use tiny amounts of radiation — approximately the same amount you could otherwise expect to receive over a three- to five-year period, making CT scans a safe way to help your doctor diagnose a wide range of conditions.

How an MRI scan works

On the other hand, MRI, or magnetic resonance imaging, uses magnets, rather than radiation, and radio waves to create precise, 3D images. During the exam, you lie still on a table while large magnets rotate around your body. Depending on the reason for your scan, your MRI may take 10 minutes or more than an hour.

An MRI scan holds an edge over a CT scan in picturing tumors and other abnormal features in soft tissues. As another benefit of MRI technology, MRI machines do not use radiation, making them a preferred option for many patients.

Sometimes, a contrast agent will be used with an MRI to help the technician produce better images for your doctor to review.

Similarities between CT and MRI scans

Both CT and MRI technology use large machines, but these scans share more similarities in benefits than appearance. Each type of imaging scan is safe and noninvasive, and both help physicians diagnose illnesses and injuries. A CT and an MRI scan can take pictures of many of the same internal structures, including organs, bones, and tissues.

The patient experience during a CT or an MRI is also very similar. During both, you will be asked not to wear any metal objects. You will lie still on a table that moves into the machine, although the entire body may not need to enter the scanner. If you have a metal implant or other health concerns, you may not be eligible for certain scans.

Both types of imaging studies may require the use of a contrast dye. Some MRI and CT scans require a special contrast dye that provides a better view of the area your doctor wants to investigate. The dye is injected just before the exam, and your body eliminates it naturally as waste.

Main differences between CT and MRI

MRI and CT scans use different technologies, which have their own benefits when it comes to uncovering medical issues. CT scans create images of bones and soft tissues. However, MRI scans can be more effective at exposing subtle differences between types of tissue.

A CT scan and an MRI scan both produce detailed images of internal structures, but compared with an MRI scan, a CT scan is more beneficial for diagnosing certain conditions. A CT scan can show bones, tissues, and blood vessels in a single image, which is difficult for an MRI scan. These include:

  • Abnormalities of the chest and lungs
  • Blood clots in the lungs or arteries
  • Certain types of cancer
  • Complex bone fractures
  • Emphysema
  • Fractures
  • Head injury
  • Heart abnormalities or disease
  • Osteoporosis
  • Tumors in the brain, bones, or lungs
  • Vascular diseases

On the other hand, an MRI scan can help physicians diagnose or treat issues such as:

  • Aneurysms and stroke
  • Breast cancer and other cancers
  • Heart disease and conditions that affect the blood vessels
  • Injuries to tendons, muscles, ligaments, bones, and joints
  • Spinal cord disease or damage
  • Traumatic brain injury
  • Urethra, uterine, bladder, vaginal, or rectal issues

Your doctor will take additional factors into consideration when deciding on which scan you need. For example, because MRI machines rely on magnets, people with certain types of pacemakers and other medical implants may not be able to have an MRI.

Using imaging to get answers

There are many reasons your provider may order an MRI scan over a CT scan and vice versa. American Health Imaging offers diagnostic imaging using the same high-quality equipment and trained personnel you would expect in a hospital at up to 60% less cost.

Choosing the most appropriate scan provides the best information for a quick diagnosis. Depending on your symptoms, one scan may be more beneficial compared to the other. No matter which scan you need, the experts at American Health Imaging are here to help.

Whether you need a quality, convenient MRI or CT scan, American Health Imaging can help. Request an appointment today!