If your doctor requests an advanced imaging scan to aid in making a diagnosis, two of the most common tests requested are the CT Scan and MRI. Let’s take a look at how each of these tests show cross-sectional pictures of the body using different techniques.
CT stands for computerized tomography. This scan uses multiple x-rays that are taken at different angles in order to produce a cross-sectional image.
MRI stands for magnetic resonance imaging. Here a combination of magnetic fields and radio frequencies are used, so the MRI scanner can generate a 3D image of the part of the body being examined.
Both of these techniques can be used to examine the same parts of the body, and the choice of which one should be used is based on the possible diagnosis. In general, CT scans are used for diagnosing serious injuries to the head, chest, spine, abdomen, and pelvis, and are helpful when trying to determine if fractures are involved. In contrast, the MRI does a better job of diagnosing issues in joints, tendons, ligaments, and soft tissues. MRIs are often used to scan the brain, spine, neck, breast, abdomen, and muscles.
Differences between a CT Scan and MRI
- Radiation – CT scans use X-ray technology so minimal radiation exposure is present. CT scans are not usually used during pregnancy for this reason. MRI’s do not involve radiation.
- Cost – CT scans are usually less expensive than MRI tests.
- Time for Procedure – CT scans are done fairly quickly. Most CT scans take around 5 minutes to complete. MRI’s can range from 15 minutes to 2 hours depending on the part of the body that is being examined.
- Patient comfort – CT scans are done in an open machine so concerns about being in a small space are rarely an issue. MRI’s are traditionally done in a narrow tube, and can sometimes cause anxiety. Hampton Roads Orthopaedics & Sports Medicine has an open MRI machine to help with concerns about anxiety if MRI is the best choice for the diagnosis.
- Limitations – The table used in CT scans accommodate approximately 300 pounds, so if a larger table is required, a patient may need to go to a facility with appropriate equipment. MRI machines with the conventional tube design may also have limitations based on the size of the patient. Open MRI machines would be an alternative option. In addition, MRI machines utilize magnetic fields during the scan so patients with certain metal objects implanted in the body (e.g. pacemakers, rods, some prosthetic joints, and even certain tattoos) may prevent the use of MRI tests.
Your doctor will discuss the type of test that they are considering to make the diagnosis. If you have any questions or concerns please share that with your specialist. Schedule an appointment at one of our seven locations!