Magnetic Resonance Imaging (MRI) technology has revolutionized medical imaging because it provides detailed images of the body's internal structures without the risks associated with invasive procedures. However, it is not entirely without concerns.
The high levels of noise generated during scans, particularly in 3T and 7T machines with their stronger magnets, pose risks to hearing and may contribute to patient discomfort.
This article explores the importance of ear protection during procedures and why it is crucial for patient safety and imaging quality to ensure better experiences and diagnostic results.
Can the Noise Generated From an MRI Damage Hearing?
MRI is a medical imaging technology that utilizes strong magnetic fields to produce detailed images of the patient’s internal structures, particularly soft tissues and organs, where traditional X-rays sometimes fall short. Because it doesn’t use ionizing radiation, it is also typically considered safer than X-rays.
However, as with most things, it’s not entirely without risks. The radio frequencies used during the procedures can cause energy to be absorbed by the body as excess heat, which can cause burns, especially in patients with certain tattoos or permanent makeup. The potential for issues with heating increases during longer scans.
Another potential issue is that the magnetic fields within the machines change throughout the procedure and create loud knocking noises, just below thresholds that are considered acceptable. If protection is not used, the patient’s hearing may be damaged.
What About Patients With Implants and External & Accessory Devices?
Patients with metal implants such as plates and screws used to repair badly broken bones or those with artificial joints, cochlear implants, pacemakers, or any foreign objects are at higher risk. External devices like insulin pumps, braces, wound dressings, and accessory devices like medical monitors and ventilators also present patient risks.
The problem is that the strong magnetic field of the MRI scanner pulls on any metallic magnetic materials inside or outside the patient. This can cause heating, burns, and even the unwanted movement of implants or devices. It can also cause electrically active devices like pacemakers to malfunction.
Furthermore, implants and other devices interact with the magnets and cause distortions that reduce image quality.
Therefore, patients with these devices should not have an MRI unless a doctor has identified their particular devices as safe. Generally speaking, only devices containing no metal and not conducting electricity are safe in an MR environment.
Characteristics of MRI Acoustic Noise
The magnetic field is the primary source of acoustic noise that occurs during the rapid changing of the magnetic currents within the gradient coils. It can be heard as loud tapping, knocking, chirping, or squeaking sounds.
These noises are from the gradient coils moving and impacting against their mountings. The mountings also flex and vibrate, creating additional noise. The level of noise that they produce ranges between 65 decibels and as high as 130 decibels in machines with stronger magnets like 3T and 7T.
Occupational Health and Safety, or OSHA, recommends a maximum permissible Sound Pressure Level of 140 decibels. It means that MRIs with more powerful magnets are reaching acceptable limits. The 1.5T machines are quieter and generally safer.
4 Reasons Why Hearing Protection Is Important During an MRI
Prevent Hearing Damage
The loud knocking noises heard as the magnetic field continually changes during the exam can damage hearing. This is why hearing protection should be worn. The stronger the machine, the louder the noise and the higher the risk.
Since 3T and 7T MRI machines produce noise levels near the permissible limits set by OSHA, around the level of a rock concert, it’s strongly recommended to wear hearing protection.
Reduction of Anxiety and Stress
Being inside the bore of an MRI machine can feel uncomfortably small when patients are already stressed and anxious about the procedure or in anticipation of the results. Hearing protection can help patients tune out the walls and noise around them and reduce their anxiety and stress.
Help Prevent Claustrophobia
Some patients will also experience claustrophobia inside the machine. For those prone to claustrophobia, requesting an open MRI scanner rather than one with a closed bore can be helpful, but it may not be available, especially when more powerful machines are required. Using hearing protection can help ease some of the suffering of claustrophobic patients.
Improve Imaging Quality
If the patient is uncomfortable with the sounds and moves in response, this will blur the image and reduce the quality, possibly necessitating additional scans. Hearing protection dulls the loud noises banging or knocking in their ears, making them less likely to move and impact image quality.
Frequently Asked Questions
How Loud Is an MRI?
Depending on the strength of the magnetic field, an MRI can be between 65 and 130 DB. The more powerful 3T and 7T machines are the loudest, while 1.5T and less powerful machines are quieter.
Do You Need Ear Protection for an MRI?
You should wear ear protection during an MRI to protect your hearing and reduce stress, anxiety, and claustrophobia. Ear protection also allows patients to relax better and improves image quality, reducing the chance of needing to repeat the images.
What Is the Best Type of Ear Protection for an MRI?
Earmuffs and earplugs will help block a significant portion of the sound. However, they must be non-metallic and approved by the radiologist so they do not reduce image quality or present safety hazards for the patient.
Final Thoughts
Using hearing protection during MRI scans is crucial for safeguarding patients’ hearing and enhancing their overall experience. The high level of noise produced, especially in machines like 3T and 7T with more powerful magnets, can lead to auditory damage and increased anxiety in patients.
Healthcare providers can help mitigate these risks by utilizing approved ear protection, promoting a more comfortable and efficient imaging process. For those looking to enhance their imaging services, Maven Imaging offers a range of imaging solutions to improve patient care.
