What is the Difference Between a CT and a MRI Scan?

By: John Hinson | On: September 14, 2015

If you’ve ever heard of a Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) machine, you may have wondered about the difference between the two. Both machines look nearly identical, since they each feature a round ‘donut’ and a movable bed where the patient is scanned. Both machines are designed to take images of selected, internal parts of the body. They are often even used on the same areas of the body!

What, then, is the difference between a CT and a MRI scan?

The Difference Between a CT and a MRI Scan

While MRI and CT scanners look similar and serve many of the same purposes, they are not the same machine.

CT Scans

CT scans utilize X-rays, which are radioactive, to capture individual image slices of the body. They are effective at making detailed images of the head, abdomen, chest, skeletal system, and more. CT scans are generally quieter and more comfortable for the patient, and faster than MRI scans.

MRI Scans

MRI scans utilize a combination of radio frequency pulses and strong magnetic fields to capture images of the body. While MRI scanners can also be used to make images of the head, abdomen, and chest just like a CT scanner, they do not scan bone. They are particularly effective at making images of soft tissue. No radiation is involved in an MRI scan, but they do take longer and are generally noisier.

Is One Type of Scan Better than the Other?

It depends. Both machines have their advantages and disadvantages. A lot of the deciding factor about which to use will boil down to the type of injury you have, as well as preference.

What is the Difference Between a CT and a MRI Scan? - Florida Medical Clinic BlogAdvantages of CT Scans

  • Patients who have metal fragments or devices can use a CT scan because no magnetic field is involved.
  • Claustrophobic patients may find a CT scan more comfortable, as they are shorter and less noisy than a MRI.
  • CT scans are particularly good at imagining bones for accurate diagnosis of injury or disease.
  • CT scans are less sensitive to patient movement during the procedure.
  • With CT scans being faster than MRI, they are better to use during emergency situations.

Advantages of MRI Scans

  • MRIs do not use radiation, unlike CT scans, and are safe for use on patients who require multiple scans, and children.
  • MRIs are particularly good at imagining soft tissues. The radio frequency can even be adjusted to better highlight the tissue in question.
  • The scanning plane in an MRI can be adjusted without having to move the patient.
  • The type of contrast agent used for a MRI scan has a far lower chance of causing an allergic reaction in the patient.

Some Examples of Which Scanner Would be Used in Different Situations…

What is the Difference Between a CT and a MRI Scan? - Florida Medical ClinicThe list below is not comprehensive. Everyone’s situation is unique. Your doctor will know which is best for your particular situation.

  • Patients with spinal injury would use a CT scan as long as they don’t have metal implants.
  • Patients with internal bleeding or other injuries would use a MRI scan to obtain the best detail.
  • If a patient has a history of allergies, it may be best for them to use a MRI scan.
  • Claustrophobic patients may be able to better tolerate a CT scan since it has a shorter duration.

Common Questions about CT Scans

What does CT Scan stand for?

‘CT’ stands for Computed Tomography.

CT vs CAT scan – Is a CT Scan the Same as a CAT Scan?

CT and CAT scans are the same thing. CAT stands for ‘computerized axial tomography’, and the term CT or CAT can be used interchangeably.

What Does a CT Scan Machine Look Like?

CT and MRI scanners look very similar to each other. They both feature a ‘donut’ which houses the scanning equipment, and a bed which moves through the scanner. Both machines feature a communications system for the patient to speak with the technician. The type of system (microphone/headphone, integrated, etc,.) depends on the model of the particular machine.

If you’re curious about CT scans and how they work, check out our informational page here!

Florida Medical Clinic Radiology Department

The Florida Medical Clinic Radiology Department offers both CT and MRI scanning services. We are certified by the American College of Radiology (ACR), an accreditation which is only earned by achieving superior service and passing an intensive evaluation of the facility and staff.

Our radiologists and technologists are all licensed and certified. This means that not only can you have peace of mind during your procedure, you’ll receive the best quality scans and the most accurate evaluations of your imaging.