Magnetic Resonance Imaging (MRI) is a diagnostic technique that uses a powerful magnetic field and radio waves to create detailed images of organs and tissues within the body. The procedure is non-invasive because it does not use ionizing radiation, making it a very safe tool for medical diagnosis. Many individuals scheduled for this scan wonder if the process itself can cause a feeling of being unwell. While the MRI machine does not chemically or biologically make a person sick, unique environmental factors and, in some cases, the use of a contrast agent, can trigger temporary physical and psychological reactions that may feel like sickness.
Physical Sensations During the Scan
The environment inside the imaging bore can produce several sensations that contribute to patient discomfort. The most frequently reported issue is the extreme operational noise generated by the rapid switching of the magnetic field gradients. This process causes a loud, repetitive knocking, thumping, or whirring sound that can be overwhelming, even when wearing hearing protection.
This loud noise is sometimes accompanied by subtle physical feelings, such as a slight vibration or movement felt throughout the body. In rare instances, patients may also report a mild sensation of warmth or tingling in certain areas. This occurs due to the interaction of the changing magnetic fields with the body’s tissues. These feelings, while harmless, can be disorienting and may contribute to a feeling of unease during the procedure.
The most common cause of feeling unwell during the scan is related to the confined nature of the machine bore. For individuals with claustrophobia, the narrow, enclosed space can quickly induce anxiety, panic, or distress. These psychological responses manifest as acute physical symptoms such as rapid heart rate, hyperventilation, lightheadedness, dizziness, and nausea. These anxiety-induced symptoms are often mistaken for a direct reaction to the machine itself but are the body’s response to the fear of confinement.
Reactions to Contrast Agents
Physical reactions are often related to the use of Gadolinium-Based Contrast Agents (GBCAs). These agents are injected intravenously to enhance the clarity of specific tissues in the images. Gadolinium’s magnetic properties improve the visibility of blood vessels, inflammation, and tumors. The injection itself may cause a fleeting cold sensation as the substance enters the bloodstream.
Once injected, GBCAs may cause several common, mild side effects. These can include a temporary metallic taste in the mouth or a feeling of warmth spreading across the body. Some patients also experience mild nausea, a headache, or minor discomfort at the injection site. These effects are usually brief and resolve quickly without intervention.
True immediate hypersensitivity or allergic reactions to GBCAs are uncommon, occurring in approximately 1 in 1,000 cases. These reactions are usually mild, presenting as a rash, hives, or itching on the skin. Moderately severe reactions, which may involve respiratory distress or widespread swelling, are much rarer, with an incidence of about 1 in 5,000 cases. Medical staff are trained to monitor for and manage these reactions and are prepared to provide immediate care should a severe reaction occur.
Steps to Minimize Discomfort
Patients can take several proactive steps to mitigate discomfort associated with the MRI experience. For the loud operational noise, wearing the provided earplugs or headphones is highly effective, and listening to music can help distract the mind from the rhythmic sounds. Communicating any anxiety or claustrophobia to the technician before the scan allows them to offer options, such as a blanket for warmth or positioning the patient feet-first for certain scans.
To manage feelings of confinement and anxiety, relaxation techniques can be used during the procedure. Focusing on deep, slow breathing, such as inhaling for a count of four and exhaling for four, can help regulate the nervous system and calm anxious thoughts. Many centers also provide a squeeze ball or call button, which gives the patient control and the ability to immediately alert the technologist if they need a break.
For patients with severe claustrophobia, a physician may prescribe an oral sedative to be taken before the appointment. It is important to arrange for a ride home if using sedation, as it impairs the ability to drive. Remaining as still as possible during the scan is also advised, as movement can blur the images and require the sequence to be repeated, extending the total time spent inside the machine.