The Strengths of MRI Scanner Noise
Magnetic resonance imaging (MRI) scanners have been helpful for doctors and patients to see a clear image of the brain, spinal cord, or other body parts. The images are used to make a medical diagnosis.
A common concern are the powerful sounds that emanate from the 3-Tesla (3T) MRI scanners, which can reach noise levels between 125.7 to 130.7 decibels (dB) and on average have the equivalent of 110 to 115 dB. To put that in perspective, it can take at least 85 dB to cause permanent hearing loss or tinnitus.
The noise created, has mainly a low frequency. This causes less damage to a patient’s hearing than noise in the higher 4 kHz range.
When considering the dangers of hearing loss from an MRI scanner, it’s important to take into account the intensity, spectrum, and the amount of time spent being exposed to these noises. The highest permissible exposure limit (PEL) is 90 adjusted decibels (dBA) for eight hours. The PEL rises by 5 dB, when the exposure duration is cut in half. For example, 95 dB for four hours, and 100 dB for two hours. If the average MRI scan is one hour long, the PEL would rise up to 105 dBA. Today’s 3T MRI scanners can go past the PEL and cause hearing loss.
Patients are usually given hearing protection during the scan, which would then only expose them to 30 dB. This is safe enough to prevent any permanent hearing loss.
A study that was conducted showed that patients who wore earplugs during an MRI scan may have minor, temporary hearing loss, but are not likely to suffer permanent damage. Patients who did not wear earplugs while they were scanned, had a higher risk of hearing loss if they needed frequent MRIs or are more inclined to develop noise-induced hearing loss.
Additional Concerns About Scanner Noise
Generally, MRI scanning sounds are not necessarily dangerous to your hearing, as long as patients wear properly fitted hearing protection during the scans. It’s important not to be over confident about this matter. If patients do not wear the earplugs properly, the risk of hearing loss would increase, especially from patients who regularly need an MRI scan.
Even more powerful 9T MRI scanners have been distributed to medical facilities, which could increase the risk of noise levels reaching past 150 dB. With these levels, any type of hearing protection would be futile in preventing hearing loss. Scanner manufacturers should look for ways to make modern machines quieter. Using some of the noise reducing techniques that are used in cars and airplanes might help tackle this problem.
If you, or a loved one, are getting an MRI scan, make sure whomever is undergoing the scan is wearing properly fitted hearing protection. This will diminish any risk of temporary or enduring hearing loss. If you, or a loved one, are experiencing hearing loss please contact us at Pure Sound Hearing Aids for a free hearing test and consultation.