MRI, CT, X-ray —What’s the Difference?

You’ve heard the terms – MRI, CT scan, and X-ray. Chances are you know these are imaging scans used to evaluate and diagnose patients. But do you know how and why they’re used?

Medical imaging has become a huge part of patient care, in both hospital and clinic settings. Whether it’s a bone fracture, heart complication or lump in the breast, your physician now depends on this technology for diagnosis and treatment.

Multiple types of imaging scans are used each day and understanding the difference can be confusing. Kurt Brauer, BS, RT (R) (MR), Inpatient Imaging manager at Memorial Medical Center, breaks down the major technologies below so you’ll better understand what’s involved the next time your doctor recommends a scan.

Diagnostic Imaging is the most common study and is often used to diagnosis injury or illness. A picture is taken, then presented on a monitor, which immediately shows the medical team what they’re dealing with. It involves small amounts of high-energy radiation that provides detailed images of the body. Evaluating bone fractures, abdominal cramps and chest X-rays are just few of the ways it’s used. With special techniques, this imaging also provides early detection of breast cancer through mammography.

Magnetic Resonance Imaging (MRI) uses a combination of a strong magnetic field and radio frequencies to obtain images of the body. It’s best for soft tissues like what’s around the brain and spinal cord and is often used to find tumors, injuries and infection. The scan can take up to 90 minutes, and it doesn’t involve radiation.

Computerized Tomography (CT or CAT Scan) plays a huge role in emergency medicine since it can be done in just two minutes. It combines a series of X-ray views taken from different angles to produce images of the bones and tissues. The image is presented on a screen that can be manipulated to allow physicians to look for fractures and lesions. It’s often used on stroke patients to evaluate brain damage.

Ultrasound imaging involves exposing parts of the body to high-frequency sound waves to show images of the body. It does not involve radiation and is most commonly used during pregnancy to monitor the fetus. It’s also used to exam the kidneys and liver. 

“Gone are the days where film has to be physically developed,” Brauer said. “Digital X-rays are in our rooms and portable devices. Everything is instantaneous. Patient care, efficiency and quality of operations have all greatly improved.”

For more information on these techniques, visit Memorial Medical Imaging.