What’s The Difference Between A CT Scan And An MRI? - Crozer-Keystone Health System - PA

Published on January 15, 2013

What’s The Difference Between A CT Scan And An MRI? 

You’ve visited the doctor, and she ordered an MRI. And you’re wondering whether a CT (or CAT) Scan would make more sense. But then again you don’t really understand the difference between the two technologies, and what works best in a given situation. (Hopefully, your doctor does know difference!)
So let’s take a look at MRIs and CT Scans to better understand the differences between the two. The most important thing to understand is that one is not better than the other; they’re just different tests, and better at helping to diagnose different ailments and issues.

MRI stands for Magnetic Resonance Imaging. MRIs are best for determining the nature of soft tissue injuries, such as ligament and tendon problems. A little bit of science - MRIs work because the body’s soft tissue is made up of largely of water, and the electrical make-up of water molecules (lots of protons) reacts a certain way to magnetic fields, thereby showing an image. The main advantage of MRI is that it does not use radiation, while CT Scans do. A disadvantage is that an MRI may take longer than a CT –  about 30 minutes, during which the patient has to lie perfectly still.
An MRI does not hurt in any way, and is completely noninvasive.

CT Scan stands for Computed (Axial) Tomography. Tomography is the process of generating a two-dimensional image of a section through a 3-dimensional object – like your body. The procedure uses X-rays, but offers a more detailed image than a traditional x-ray. This is because the CT scanner emits a series of X-ray beams through your body from different angles, providing a 3-D image rather than a two-dimensional X-ray image.
CT Scans are most often used to determine the extent of bone injuries, as well as imaging chest and lungs and cancer detection.

CT Scans usually only take about five minutes to complete.
Generally speaking, CT Scans are painless. However, your doctor may want to use a contrast dye to make the images show up better on a screen. So there could be some discomfort involved, but nothing major. You’ll probably be asked to fast for a while before the scan. And importantly, women who suspect that they’re pregnant should be sure to tell the doctor when she orders a scan.

So which is a better test – an MRI or a CT Scan? The answer is neither; it depends on what the doctor is looking for.

For more information about Crozer-Keystone medical imaging services, or to schedule an appointment, call 1-866-5-CK-XRAY (1-866-525-9729) or visit http://ckimaging.crozerkeystone.org.


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