MRI and CT scans are exams that show the inside of the body in detail. That is why people often confuse the two. The choice between them is up to the doctor, who considers the clinical suspicion, the area to be examined and how urgent the case is.
| CT | MRI | |
|---|---|---|
| How it works | X-rays processed by a computer | Magnetic field and radio waves |
| Radiation | Yes, at a controlled dose | No |
| Duration | Usually quick | Usually takes longer |
| Noise | Little | Loud, rhythmic noises |
| Metal in the body | Usually not a problem | Must be reported beforehand |
| Pregnant women | Only on some areas, with the abdomen protected | From the end of the third month |
When CT is usually ordered
Because it is quick, CT is widely used in injuries and emergencies. It is also the most suitable exam to assess the lungs: a chest CT shows the lungs in more detail than an MRI. And it is widely used to assess bones and blood vessels, including CT angiography of the heart arteries.
When an MRI is usually ordered
MRI shows soft tissues in great detail. That is why it is widely used to assess the brain, the spine, joints (such as the knee and shoulder), the breasts, the prostate and organs of the abdomen and pelvis. When investigating abdominal diseases, ultrasound and MRI are usually the preferred exams.
One exam is not "better" than the other
Each one answers different questions better. In some cases, the doctor orders both to combine the information. If you are unsure why one of them was ordered, ask your doctor.
Informational content. It does not replace your doctor’s advice.
