Actor Nafisa Ali recently gave her Instagram followers a glimpse of her MRI appointment, but her description of the experience caught attention. Sharing a picture from the scan, she wrote, “Me doing my MRI today, awaiting the results …but the room looks festive. MRIs are really noisy…!”Anyone who has undergone an MRI scan might relate to her comparison. The machine can produce a surprising range of sounds, from loud knocking and rhythmic thumping to high-pitched beeping and buzzing. But why does a medical scan that captures detailed images of the inside of the body sound almost like a construction site?The answer lies in how the machine works. An MRI uses powerful magnetic fields and radio waves to produce images of organs, tissues and other structures inside the body. During this process, certain components inside the scanner vibrate, producing the noises patients hear.“MRI scans are noisy because the machine’s internal metal coils rapidly vibrate when high-voltage electrical currents switch on and off inside a powerful magnetic field. These vibrations create loud mechanical sound waves that echo inside the hollow scanner tunnel,” explains Dr Madhu Prashanth D, Senior Consultant and Head – Radiology & Imaging, Vascular & Interventional Radiology, Sakra World Hospital, Bengaluru.DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine. View this post on Instagram A post shared by Nafisa Ali Sodhi (@nafisaalisodhi) These components are known as gradient coils. They help the scanner locate signals coming from different parts of the body. Dr Shubham Sulania, Consultant Radiology, Kailash Deepak Hospital, explains that these coils create tiny, carefully controlled variations in the magnetic field.“When fast electrical currents flow through them in the presence of the scanner’s powerful magnetic field, physical forces act on these coils, making them vibrate. Patients perceive the sound waves produced by these vibrations as tapping, knocking, or buzzing sounds,” he says.Why does an MRI machine sound like knocking, hammering and beeping?Depending on the type of scan, patients may hear repetitive tapping, clicking, buzzing and loud rhythmic thumping. Some sounds can even resemble rapid hammering.Story continues below this adDr Prashanth describes the range as “heavy knocking and thumping”, high-pitched chirping and beeping, and noises resembling grinding or sawing.The sounds may also change several times during the procedure. There can be periods of particularly loud noise followed by quieter intervals. Dr Sulania explains that this happens because the scanner follows different sets of instructions, called imaging sequences, to capture different images.“These sounds should be explained to the patients beforehand so that they know what to expect and do not mistake them as a sign of something being wrong,” he says.Are some MRI scans louder than others?If you have found one MRI scan noisier than another, there is a reason. The volume depends on the scanner’s design, magnetic field strength and the imaging technique being used.Story continues below this adDr Prashanth explains that stronger magnets, such as 3-Tesla machines compared with 1.5-Tesla machines, and faster imaging sequences generally produce louder sounds.Dr Sulania adds that even during the same examination, the noise can vary depending on the images being captured. “Some sequences have faster or stronger changes in the magnetic fields. This can make louder sounds,” he says.However, newer MRI technologies are making the experience quieter. Some machines feature acoustic-reduction software or specialised ‘silent’ sequences that soften the changes in the magnetic field, making certain scans noticeably quieter, Dr Prashanth says.Also Read | Deepinder Goyal’s Rs 85,000 fitness device faces doctors’ scrutiny: ‘We’ve made no medical claims’Can the loud noises make patients panic? An MRI, or Magnetic Resonance Imaging, is a scan that uses powerful magnetic fields and radio waves to produce detailed images of organs, tissues and other structures inside the body (Image: Unsplash)Being inside a narrow scanner tunnel while hearing repeated banging and knocking can be uncomfortable. For some patients, particularly those undergoing their first MRI, the combination of a confined space and loud noises can trigger anxiety or claustrophobia.Story continues below this adDr Prashanth points out that noise levels during some MRI scans can reach around 100 decibels. Sudden sounds can startle patients, but they are also asked to remain still throughout the procedure for another reason. Even small movements can blur the images, meaning that the affected part of the scan may have to be repeated.Dr Sulania says unfamiliar sounds can be particularly unsettling for first-time patients. “Particularly when a patient is lying inside the scanner, the loud, rhythmic knocking and abrupt tapping can be rather startling,” he says.This is why explaining the procedure beforehand is important. “We tell them that these sounds are typical throughout the imaging procedure and do not indicate a problem,” he adds.How do hospitals protect patients from the noise?Patients are provided with hearing protection to reduce discomfort and protect their hearing. This usually includes foam earplugs or over-the-ear headphones, and sometimes both. Some centres also offer headphones that play music during the scan.Story continues below this adDr Prashanth adds that technologists may give patients a handheld squeeze ball to press if they feel overwhelmed and need to pause the procedure.DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.