CAT, MRI and X-ray – What’s the Difference?

What is the difference between CAT, MRI and X-ray scans?

Doctors routinely order imaging tests to help identify an accurate diagnosis. Whether you have symptoms or are asymptomatic, these tests help your doctor deliver an accurate and timely diagnosis so you receive the necessary medical interventions.

Three of the most common imaging studies are CAT scan, MRI and X-ray. While distinctively different, each imaging test allows your doctor to “see” inside your body. They are all painless and noninvasive. Here are some of the basic differences between them:

CAT scan:

Commonly abbreviated “CT,” a CAT scan stands for computed tomography. Depending on the test, a patient might receive an IV or oral X-ray dye to help visualize internal structures. CAT scans are commonly used to evaluate your brain, abdominal and pelvic organs, blood vessels and bones. CAT scans can help identify cancer, heart disease, blood clots, bone fractures and more. A CT scan study typically takes about 15 minutes.

MRI:

Similar to a CT scan, an MRI (magnetic resonance imaging) scan takes many detailed images. The MRI tunnel-shaped machine produces images from various angles within the body, creating cross-sectional images of organs and tissues. Unlike a CT scan that uses X-ray, the MRI uses a magnetic field and computer-generated radio waves to create images. Depending on the test, the patient might receive an IV dye to aid in visualizing structures.  MRI is commonly used to evaluate the brain, spine, joints such as the knee and shoulder, blood vessels, and certain internal organs. Before an MRI, a screening questionnaire is completed to ensure that you do not have any implanted electrical devices, such as a pacemaker or other implanted device(s) that may prohibit you from having an MRI. An MRI scan typically takes 20 minutes to one hour to complete, depending on the test.

X-ray:

As the name implies, an X-ray machine produces electromagnetic radiation through X-rays to generate images.  X-rays are good at imaging bones and are commonly used to take pictures of the chest, extremities and spine. They are useful as first-line imaging because they can be produced quickly and efficiently and do not typically require any insurance pre-approval.  X-rays are also used throughout the hospital and can be obtained with a portable machine. Portable machines are used extensively in surgery because they produce real-time motion images, aiding physicians during surgery.