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Understanding MRI, CT, and CT Myelogram Scans: What’s Right for Your Spine?

Written by Sukanya Chebrolu, MS and Chukwunonso C. Ilogu, MD, MS of the LESS™ Society Back or neck pain can be frustrating especially when the cause isn’t clear. That’s when imaging tests come in (1) . While an x-ray shows bone structure and alignment, it doesn’t always reveal what’s happening with your discs, nerves, or soft tissues (2).

That’s why your doctor might recommend an MRI, CT scan, or sometimes a CT myelogram to get a clearer picture of your spine. This guide explains what each test does, how they differ, and when they’re typically used. Why Not Just an X-ray?

An X-ray is often the first step when evaluating spine pain. It’s quick, inexpensive, and useful for spotting fractures or misalignment. But it can’t show soft tissues like discs or nerves. If your symptoms suggest a nerve issue, disc problem, or other soft tissue condition, your spine specialist may recommend an MRI or CT scan for more detail. Understanding MRI, CT, and CT Myelogram

Before comparing them, let’s look at what each scan actually does:

  • MRI (Magnetic Resonance Imaging) uses strong magnetic fields and radio waves to create detailed pictures of soft tissues like discs, nerves, and ligaments without radiation.

  • CT (Computed Tomography) uses X-rays to create cross-sectional images of your bones and joints. It’s quick and provides fine detail, especially for bone structure.

  • CT Myelogram is a specialized CT scan used when MRI isn’t possible (for example, if you have a pacemaker). A contrast dye is gently injected into the space around your spinal cord, allowing doctors to see nerves and the spinal canal clearly (3). Now that we’ve explored how MRI, CT, and CT myelogram scans work, let’s take a closer look at what these imaging techniques actually look like in practice.


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    Image 1: A doctor guiding a patient into an MRI scanner for a spinal imaging test. MRI scans use magnetic fields to create detailed images of soft tissues, helping detect disc or nerve issues. What to Expect During the MRI, CT Scan

    Both MRI and CT scans are safe and non-invasive. You’ll lie still on a table while the machine captures images.

    • MRI: The scanner is a tunnel-shaped magnet. It’s noisy, but ear protection helps reduce discomfort.

    • CT: The scanner is open and quieter, and sometimes a contrast dye is used to highlight certain areas.

    A few tips to make your scan smoother:

    • Wear clothing without metal zippers or snaps.

    • Let your doctor know if you have implants, a pacemaker, or are pregnant.

    • Follow any instructions about food, drink, or contrast dye.

    You can usually return to normal activities right after the scan. To help you easily compare these diagnostic tools, here’s a side-by-side breakdown highlighting their key differences in purpose, technology, and patient experience.

Feature

MRI

CT Scan

Best for

Soft tissues (discs, nerves, ligaments)

Bones, joints, and fine bone detail

How it works

Magnetic fields and radio waves – no radiation

X-rays – small amount of radiation

Typical purpose

Suspected disc herniation, nerve compression, or soft tissue damage

Fractures, bone spurs, or surgical planning

Time

30–45 minutes

5–10 minutes

Noise level

Loud (ear protection provided)

Quiet

If you have metal or a pacemaker

Usually not safe

Safe alternative

Key Takeaways

  • MRI shows soft tissues like discs and nerves (4).

  • CT shows bones and joint structures in detail.

  • CT myelogram is useful when MRI isn’t possible or when nerve visibility needs enhancement.

Always tell your doctor about any metal implants, pacemakers, or allergies before your scan.

Learn More About Your Spine Health

If you’re unsure which imaging test is right for you, your spine specialist can guide you based on your health history and symptoms.

Visit The LESS Society™ to learn more about spine imaging, minimally invasive approaches, and finding a specialist near you. Frequently Asked Questions 1. Why do I need an MRI or CT if I already had an X-ray? A1: X-rays show bones but not soft tissues. MRI and CT scans give more detail when an X-ray doesn’t explain your symptoms.

2. I have a pacemaker can I still have an MRI? A2: Usually not. MRI uses strong magnets that can interfere with pacemakers. Your doctor may recommend a CT or CT myelogram instead.

3. What is a CT myelogram, and why would I need one if I already had an MRI? A3: Sometimes an MRI doesn’t provide a clear view due to metal implants or motion. A CT myelogram uses contrast dye to highlight nerves and spinal fluid, offering sharper images for diagnosis. References:

  1. Modic MT, Ross JS. Lumbar degenerative disk disease. Radiology. 2007;245(1):43–61.

  2. Kim G-U, Park WT, Chang MC, Lee GW. Diagnostic Technology for Spine Pathology. Asian Spine J 2022;16:764–75. https://doi.org/10.31616/asj.2022.0374. 

  3. Nouh MR. Imaging of the spine: Where do we stand? World J Radiol 2019;11:55–61. https://doi.org/10.4329/wjr.v11.i4.55. 

  4. Ruiz Santiago F, Láinez Ramos-Bossini AJ, Wáng YXJ, Martínez Barbero JP, García Espinosa J, Martínez Martínez A. The value of magnetic resonance imaging and computed tomography in the study of spinal disorders. Quant Imaging Med Surg 2022;12:3947–86. https://doi.org/10.21037/qims-2022-04.

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