CT Scan vs an MRI

Patients with certain conditions may need to undergo imaging tests for their physicians to make the proper diagnosis. Two common imaging tests are the CT scan and the MRI. Below, we define each of these imaging tests and discuss their advantages and disadvantages.

What Is a CT Scan?

A CT scan is a computed tomography scan. In the past, physicians referred to this scan as a CAT scan, or a computerized axial tomography. This common type of scan, which radiologists perform nearly 70 million times per year, uses X-rays to produce various cross-sections of a specific body part. The resulting images can be more useful than X-rays, as they can depict more detail. Some common problems that a CT scan can reveal include:

  • A lack of blood flow to the brain.
  • Tumors of the brain, liver, kidneys, pancreas, and bones.
  • Brain calcification.
  • Brain hemorrhaging.
  • Bone tumors.
  • Osteoporosis.
  • Spinal cord injuries.
  • Complex bone fractures.
  • Collapsed lungs.
  • Pleural effusion.
  • Pulmonary fibrosis.
  • Kidney stones.
  • Aortic aneurysms.
  • Pulmonary edemas.
  • Blood vessel blockages.

What Is Getting a CT Scan Like?

Getting a CT scan is a relatively simple process. A physician may order that you have a CT scan taken "with contrast" or "without contrast." If your CT scan is "without contrast," you can proceed with the rest of the process.

There's an extra step for CT scans "with contrast." This means that the radiologist will have you take a contrast dye so that the image comes out clearer. If you have to take a contrast dye, a radiologist may inject it intravenously. If you need a CT scan of your digestive tract, the radiologist may ask you to drink the contrast dye. Drinking the contrast dye and receiving it intravenously are safe processes, as the dye is a substance that doesn't discolor your organs and leaves your body within 24 hours.

Once you receive your contrast dye if applicable, the radiologist will have you undress in private and put on a hospital gown or medical scrubs. Then, you'll lie down on the imaging table and the radiologist will ensure that you're comfortable. The table slowly moves into the CT scanning device so that the radiologist can capture the appropriate images. No objects touch your body during this process, as the CT scanning device collects images using ionizing radiation. The CT scanning process usually takes no longer than 10 minutes.

What Is an MRI?

An MRI is a magnetic resonance imaging test. It uses both strong magnets and radio waves to produce a clear view of your organs, tissues, and bones. They tend to produce more detailed images than both X-rays and CT scans. Some common problems that a physician can diagnose using an MRI include:

  • Abnormalities with ligaments, tendons, and joints.
  • Cancerous masses on various body parts.
  • Strokes.
  • Multiple sclerosis.
  • Crohn's disease.
  • Ulcerative colitis.
  • Cirrhosis.
  • Bone infections.
  • Blood vessel irregularities.

What Is Getting an MRI Like?

Like with CT scans, a physician can order an MRI with or without contrast. If you undergo an MRI without contrast, you can proceed with the rest of the preparation process. If you need to take contrast, the radiologist will administer it intravenously or give you a drink to swallow.

Once you ingest your contrast dye if relevant, you can take off all your jewelry and clothing in private. You'll have a hospital gown or medical scrubs to put on for the duration of your MRI. The radiologist will also give you headphones or earplugs to wear, as the MRI machine can be quite loud. When you're ready, you can lie down on the scanning table. The radiologist will cause the table to slide into the MRI machine. You will be required to stay still for the duration of the imaging process, which can take up to one hour.

Depending on what body part the radiologist is collecting images of, you may need to hold your breath at certain points. You'll only have to hold your breath for a few seconds at a time, but it's important to listen to the radiologist's instructions carefully. Slight movements may skew the MRI's results, which can result in an inaccurate diagnosis or the need to go through the MRI imaging process again.

CT Scans vs. MRIs

Here are some key differences between CT scans and MRIs:


MRIs are more expensive to get than CT scans. An MRI is usually around double the cost of a CT scan. Most insurance companies will provide at least partial coverage for imaging tests, so you can research what your provider covers. If you're paying out-of-pocket and the cost is too much to pay for, you can talk to your physician about the effectiveness of cheaper alternative imaging tests.

Sound level

MRI machines produce much more noise than CT scanners. CT scanners produce minimal noise, so you likely won't notice it during the imaging test. Alternatively, MRI machines are quite noisy and often require the use of headphones or earplugs while you're laying down for the test.

Test speed

An MRI takes longer to complete than a CT scan. An MRI takes about one hour to complete, while a CT scan takes about 10 minutes to complete. The exact time will vary depending on what body part the radiologist is scanning and whether they use a contrast dye. Patients with extreme claustrophobia or anxiety may have a more difficult time enduring the longer session of an MRI imaging test.

Image quality

MRIs typically produce higher-quality images. They can capture clear images of soft tissues while a CT scan can't. MRIs can also collect images of structures behind bones, which are areas that a CT scan may miss.

Which Imaging Test Is Right for Me?

Only a physician can determine the right imaging test for you. They'll consider factors like your medical history and the current symptoms you're presenting to make an informed decision. They may also assess certain risk factors. For example, physicians typically advise against multiple CT scans for children and pregnant women because of the risk of radiation exposure. Physicians may also advise against MRIs for patients with IUDs, eye implants, orthopedic hardware, artificial joints, and dark tattoos.

If you need an MRI or CT scan, you can visit our website to learn more about coming in for an imaging test. Once we receive the imaging order from your physician, we'll contact you to schedule a testing time. We accept most insurance plans and provide competitive cash pay rates to patients without insurance, so be sure to get in touch with us today.

2401 Ira E. Woods Ave, #600
Grapevine, TX 76051

(817) 488-9991