What is the difference between CT and MRI?

CT and MRI
CT and MRI

Despite being advanced imaging studies, there is a big difference between CT and MRI. They are done in slightly different circumstances. In addition, each has its advantages and disadvantages. If you want to know the difference between MRI and CT scan machines, just keep reading!

Magnetic resonance imaging and computed tomography are modern and accurate imaging studies. In other words, they show the structures within the human body. Both the procedure and the equipment used for a CT scan and an MRI are similar. Therefore, many people do not know the difference or why sometimes an MRI and sometimes a CT scan is done. In this article, we explain the difference between tomography and magnetic resonance imaging.

What is the difference between CT and MRI?

Magnetic resonance imaging and computed tomography are imaging studies. That is, both tests show “photographs” of the inside of the body. Thanks to this, doctors can detect diseases and abnormalities as well as plan appropriate treatment.

Some patients wonder which test they should choose: MRI or CT scan. However, the decision is always made by the specialist doctor. To perform a CT scan, a doctor’s order is required. This is because it uses ionizing radiation (mainly x-rays), which in too high doses can alter the DNA of cells. Therefore, the CT scan should not be done too often. The CT scan is done with a device called a tomograph.

MRI, in turn, uses radio waves in conjunction with a strong magnetic field. This technique uses a large device called a resonator. By itself, MRIs are completely harmless to tissues. However, there are some risks. For example, it can break down implantable devices like a pacemaker or an insulin pump.

In addition, there is also a risk when there are metal objects on the body. Some implants, bullet fragments, or even metal particles in tattoo dye can get hot and move during the procedure. This is because the resonator acts like a large magnet. In this way, some tissues could be damaged. Computed tomography does not carry such risks. The worst that can happen is that the image is blurred due to metals in the body.

Tomography and MRI: Similarities and Differences

The procedure is very similar for both tests. When you have a CT or MRI, you will have to lie down on a special table that will move into a machine with a large aperture (either CT or MRI). The person supervising the test is in a separate room, and usually communicates with the patient through an intercom. The radiology staff can give some indications such as temporarily holding your breath. In both types of studies, the patient must remain still; otherwise the images will be blurry.

One difference between CT and MRI is the shape of the device. A resonator is more like a huge tube that emits a magnetic field and radio waves. Also, it makes loud noises that are not produced during a CT scan. For its part, the tomograph is a large, very shallow ring that is used to take very precise radiographs. For your info, you can buy CT scan machines online from Amber Diagnostics.

Another important difference is the duration of the test. The MRI usually takes up to twice as long as the CT scan. When a patient needs to be quickly evaluated (for example, after an accident), the CT scan will be the exam of first choice. Another advantage of CT is that it is cheaper and is done in more facilities.

Contrast medium for tomography and resonance

The cost of both CT and MRI increases if contrast media must be administered. This is a substance that improves the visibility of some structures. In a CT scan, an iodinated contrast is mainly used. On the other hand, gadolinium contrast is the most common in an MRI. Both types of contrast can cause an unpleasant allergic reaction, but the risk is lower on an MRI.

Which is better?

Both MRI and CT are completely painless. Also, the two tests have very good precision. However, magnetic resonance imaging offers higher quality in some tissues. For this reason, a CT scan is often complemented by an MRI when it does not show clear results.



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