MRI machines and noise

MRI (Magnetic Resonance Imaging) machines use powerful magnets, radio waves, and a computer to create detailed images of the inside of the body. Here's a simplified breakdown of the process:

• Magnetic Field: The MRI machine generates a strong magnetic field that aligns the protons in the hydrogen atoms of your body's water molecules.

• Radio Waves: The machine then sends radiofrequency pulses that temporarily knock these protons out of alignment.

• Signal Detection: As the protons realign with the magnetic field, they emit signals that the machine detects.

• Image Creation: A computer processes these signals to create detailed images of the body's internal structures.[1] [2] [3]

The noise you hear during an MRI scan is primarily due to the gradient coils within the machine. These coils rapidly switch on and off to create varying magnetic fields, which are necessary for the spatial encoding of the signals. The rapid switching causes the coils to vibrate, producing loud knocking or thumping sounds. The hollow structure of the MRI machine amplifies these sounds, making them even louder.[4] [5] [6]

An operator stands next to MRI machine as a patient is about to enter for a scan.

[1] https://science.howstuffworks.com/mri.htm

[2] https://www.healthline.com/health/what-is-a-mri

[3] https://www.nibib.nih.gov/science-education/science-topics/magnetic-resonance-imaging-mri

[4] https://www.envrad.com/noises-to-expect-during-an-mri/

[5] https://radiologyblog.cincinnatichildrens.org/whats-with-all-the-noise/

[6] https://capitolimagingservices.com/why-is-an-mri-so-loud/