Hearing Protection in MRI Procedures
|Magnetic Resonance Imaging (MRI) procedures are increasingly common all
around the world, with more than 10,000 machines in service, performing over
30,000,000 scans each year.
MRI procedures are believed by virtually all authorities to be one of the safest medical scanning techniques in use, however, MRI procedures can be scary and uncomfortable due to the necessity for the patient to spend considerable time inside a small space. Add to the claustrophobia-inducing chamber, the extreme noise produced by MRI machines and many patients find the procedure quite unpleasant, if not downright terrifying.
There is nothing one can do about the size of the chamber, or the need to spend the required time inside to get the scan results needed by your doctor, but we can help protect you from the noise.
How bad is the noise in an MRI and what level of protection is recommended?
NOTE: Even with no hearing protection, most patients will not suffer permanent hearing damage during a typical MRI procedure, so do not be alarmed by the following analysis.
Noise levels inside an MRI machine during a scan typically vary from 65 to 95 dB, with intermittent spikes of noise as loud as 110 decibels, about the level produced by a rock concert.
OSHA, the US government agency charged with enforcing workplace safety, mandates that hearing protection devices be provided to workers any time the ambient noise level in the workplace exceeds 90 dB, and requires that any hearing protection devices provided reduce the noise in the ear to 85 dB or lower. Since MRI machines produce up to 110 dB of noise, to meet the OSHA standard of reducing the noise at the ear to 85 db or less, would require an NRR rating of 25 or better (110 - 85 = 25).
The foregoing is a very conservative analysis. Hearing damage from an MRI procedure is highly unlikely, even without any hearing protection. The primary reason for using hearing protection in MRI procedures is to make the patient as comfortable as possible so you can lie still letting the machine get the very best scan of which it is capable. Your physician needs the clearest and most accurate data she can get to guide her treatment decisions. So it makes sense to make sure you have adequate hearing protection during your MRI scan procedure. This is especially true of very young patients who are likely to be very frightened.
What hearing protectors meet an NRR 25 level of protection?
Most disposable foam ear plugs offer an NRR 25 or better level of protection, and virtually all MRI technicians will provide you with disposable foam ear plugs when you arrive at the facility for your MRI procedure. For those who have not had a lot of experience in using foam earplugs, however, these can be difficult to use as well as very uncomfortable. For young children, foam earplugs are not generally recommended.
A much better choice for hearing protection in an MRI procedure, is an ear muff that is rated MR Safe. Products with the MR Safe designation are certified by their manufacturers to be free of metal so that they will neither react to the extreme magnetic fields, nor will they conduct induced electrical currents that can cause non-conforming products to become very hot during an MRI procedure.
An increasing number of MRI facilities have found that providing suitable hearing protection ear muffs to their patients results in better scans from more relaxed, less nervous patients. Ear muffs are simple to use, easy to adjust so they fit properly, they are not as invasive as in-ear plugs, as well as being more hygienic when suitable protective ear muff covers are changed with each patient use.
Ear Plug Superstore offers an excellent selection of noise protection ear muffs that are all certified by the manufacturers to be MR Safe. The highest rated of these are the Pro-Ears MRI Safe Ear Muffs. The Pro-Ears Model 26 MRI Safe Ear Muff is our top recommendation for use with children as young as 3 weeks old up to small adults.
For patients who suffer from noise sensitivities, commonly referred to as hyperacusis, dual protection is recommended. Dual protection consists of wearing ear plugs under a set of ear muffs.