How MRI Machines Work: A Simple Explanation

How MRI Machines Work

The Four Major Parts of MRI Machines

After an accident or trauma, sometimes injuries that do not show up on x-rays show up on MRI machines. While broken bones appear on x-rays, damage to muscles and soft tissue appear on MRI studies. It is extremely important to consult with a doctor after an accident to determine if you need an MRI. MRIs help doctors give more accurate diagnoses and do not expose people to the harmful effects of radiation. Here are some key facts about how MRI machines work.

MRI stands for “magnetic resonance imaging” and Dr. Raymond Vahan Damadian invented it. An MRI machine has four major parts: magnets, an antenna, a computer, and software.

How MRI Machines Work Part 1: Magnets

The first major part of how MRI machines work involves the magnets. Water molecules have two hydrogen atoms which affects water exposed to magnetism. The magnets’ arrangement inside MRI machines is designed to affect magnetism; for example, if you place a compass inside of an MRI machine, the magnets would affect which way the compass points. When a human body is inside an MRI machine, the magnetism causes the water molecules to line up in one direction. MRI magnets make all the water molecules point in the same direction just like the needle of a compass.

You can switch the magnets inside of MRI machines on and off to change the direction of the magnetic field. This causes the water molecules in our bodies to rotate and spin in new directions. Even though the water is moving in our bodies, we cannot feel anything and it doesn’t consciously affect us. When the water molecules spin around, they give off a slight pulse of energy in the form of a radio wave. Each time the water molecules in your body spin in a different direction, they produce slight radio signals. This leads us to the second major part of MRI machines: antennas.

Part 2: Antennas

The second part of how MRI machines work involves antennas. Antennas inside of MRI machines detect the small radio signals given off by water molecules when they change directions. The antenna intercepts and collects the radio waves each time the water molecules change directions with the magnetic forces inside the machine. Once the radio signals from your body’s water molecules reach the antenna, the information transmits to the third major part of MRI machines: the computer.

Part 3: Computers

The third major part of an MRI machine is the computer. Computers inside of MRI machines are extremely fast and powerful. All of the faint radio signals detected by the antenna transfer to the computer and transform into data. Data from the radio signals is processed and stored by the computer inside of the MRI machine. After the data is stored on the computer, the fourth major part of how MRI machines works comes into play: software.

Part 4: Software

The fourth and final major part of how MRI machines work involves the software. The computer inside of the machine uses the software to create pictures from the radio signals received by the antenna from your body’s water molecules. It takes all of the data collected from the antenna and organizes in such a way to produce pictures of the human body. The pictures are then compiled into flat images that look like slices of bread. With the software, you can slice the human body in many different directions. This allows us to see what the inside of our body looks like without exposing it to any harmful radiation.