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Home >> Products >> Magnetic Resonance Imaging >> What is MRI?

Magnetic Resonance Imaging (What is MRI?)

How does MRI allow us to see inside the body?

MRI uses a magnetic field and radio frequencies (RF) to acquire data that can be used to generate images on a computer. What happens in the MRI system and inside the body during image acquisition? A brief explanation is introduced below.

Before examination it is confirmed that no ferromagnetic materials are present.
Before examination it is confirmed that no ferromagnetic materials are present.MRI systems generate a large magnetic field. It’s important to check whether there are any ferromagnetic materials on or inside the patient's body that could compromise image quality or pose a safety risk. Additionally, mechanical or electronic implanted devices may be contraindicated, and more information regarding these items will need to be obtained before the scan is performed.

What happens within the body

What happens within the body (1)
(1) In their natural state, hydrogen nuclei in the body are oriented randomly.

The patient is transferred into the gantry of the MRI system
The patient is transferred into the gantry of the MRI system
After the patient lies in the MRI table, its properly positioned, and advanced into the MRI gantry, the entire body is exposed to a very strong, constant and homogeneous magnetic field.


What happens within the body (2)
(2) When a powerful magnetic field is applied, the hydrogen nuclei align with the field.

Image acquisition (scanning) is performed.
Image acquisition (scanning) is performed.
Under this strong field, and after the application of RF waves, changes in the Hydrogen atoms in the body can be detected by using a special antenna, placed over the area being scanned.


What happens within the body (3)
(3) When a radio frequency (RF pulse) is applied to the field, hydrogen nuclei orient themselves in a specific direction.

= This is the magnetic resonance phenomenon.


What happens within the body (4)
(4) When the radio frequency is switched off, these hydrogen nuclei return to the original alignment status described in (2). Based on the speed of the hydrogen nuclei in returning to this status, data is acquired that can be used to assess the characteristics of the lesion.

Images are reconstructed
The image is reconstructed
After data acquisition, a powerful computer reconstructs the images which can then be displayed in a monitor for a physician to interpret.

The image is reconstructed
For more information please visit the FDA MRI page.