The Difference Between MRI and CT Scan Procedures


To a patient, learning that they need a diagnostic imaging procedure can be scary, intimidating and also confusing. If you’re unfamiliar with the field of radiology when shopping for your MRI or CT scan, being able to distinguish between different modalities (kinds of diagnostic imaging scans) can be hard to do. Sometimes, you’ll need multiple procedures completed to evaluate the same body part and you might find yourself asking:

  • Did he just say I need a CAT scan? I don’t even have a cat?
  • Are those all just fancy ways to say X-ray?
  • Did that doctor just recite the alphabet, or did she tell me I need an MRI, CT, ABC, MRA, XYZ scan?

Let’s start with the basics, explaining the difference between a CT and an MRI scan.

The Difference Between MRI and CT Scan Procedures
Image from GE Healthcare

CT scan stands for Computed Tomography scan, often referred to as a CAT scan. CT scans are images which use tomography to capture them.  Tomography is an imaging technique that creates a 2-dimensional (2D) image of a section of a 3-dimensional (3D) object.
The CT scanner creates a 3D image using digital geometry processing which is a fancy way of saying: the CT scanner takes a bunch of 2D pictures of the same thing at different angles and then puts them together to create the final 3D image.  While a CT Scan is a kind of X-ray, the final image is much more detailed than an X-ray. This is why sometimes your doctor might order a CT scan even though you’ve already had an X-ray, it gives them a better idea of what’s going on with whatever ails you.
A CT scan, on average costs about $325 on Save On Medical or as much as $1,100 at a hospital
Open vs Closed MRI
MRI stands for Magnetic Resonance Imaging which is an advanced form of diagnostic imaging that uses magnets, radio waves, and a computer to process images of the inside of your body.  MRIs are often the best way to find abnormalities and diagnose diseases in their early stages so patients can get the right treatments.  MRI images are able to show the contrasts between various soft tissues of the body; like the brain, heart or various muscles. MRIs are also often used when looking for cancers. The most notable difference between an MRI scan and CT scan, is that it doesn’t use ionizing radiation like CTs and X-rays.
An MRI costs on average, $450 on Save On Medical or as much as $1,734 at a hospital.
It’s a good idea to ask your doctor which imaging procedure is better for you, so feel free to ask plenty of questions and don’t hesitate to ask if you don’t understand the difference between an MRI and a CT scan. You’re in control of your own health, so be informed and empowered!