What can we help you with?

< All Topics
Print

Magnetic Resonance Imaging (MRI)

This imaging system is a non-invasive way of viewing the inside of an organism. It creates image slices of the organism, as if it were made out sheets of paper. When that paper is stacked on top of each other, software is used to turn it into a 3D model using voxels.

This gives us a clear picture of the inside of an organism in three dimensions without ever having to open it up with surgery.

How it Works

To know how an MRI machine works we have to know a bit about atoms. Atoms are made of subatomic particles called protons, neutrons and electrons.

Protons have a positive charge, electrons have a negative charge and neutrons have – you guessed it – neutral or no charge. You might know that the flow of electrons along a conductor (like a copper wire) is called electricity.

What you might not know is that these subatomic particles generate a magnetic field. When placed inside a larger magnetic field, the protons align with that field – like a compass always pointing to the North Pole.

The MRI machine has a gigantic ring of magnets that create a strong magnetic field. When activated these magnets align the protons in the atoms in the body. Then the machine fires radio pulses through the body (using the “gradient coils”), which temporarily knocks the protons out of alignment with the magnetic field. As the protons realign themselves with the MRI’s magnetic field they emit energy, which is picked up by radio frequency coils inside the machine, like an antennae picking up a radio station.

The protons of different materials (fat, bone, muscle) emit different amounts of energy when they realign with the field. Software within the machine takes these different energy levels and turns them into brighter or darker pixels on an image slice.

Next Laser Scanning
Table of Contents