Magnetic Resonance Imaging (MRI) is a diagnostic tool that creates detailed images of organs and tissues inside the body. While generally considered safe, some individuals experience dizziness during or after an MRI scan. This sensation is linked to the strong magnetic fields involved in the imaging process.
Understanding MRI-Induced Dizziness
The primary cause of dizziness or vertigo during an MRI scan stems from the interaction between the machine’s powerful static magnetic field and the fluid within your inner ear’s vestibular system. This system, responsible for balance, contains fluid-filled semicircular canals. Within this fluid, known as endolymph, ionic currents are present. When exposed to the strong magnetic field, these currents interact with the field, creating a Lorentz force.
This force subtly displaces the endolymphatic fluid, stimulating hair cells in the semicircular canals. This stimulation mimics head movement, causing the brain to perceive motion or dizziness, even when still. The effect is more noticeable with higher field strength MRI machines (e.g., 3T or 7T) than with common 1.5T systems.
Additional Sensations During an MRI
Beyond dizziness, individuals may experience other physical sensations linked to the MRI machine’s operation. A feeling of warmth in the scanned area can occur from radiofrequency pulses depositing energy into tissues; metal in or on the body, including some tattoo inks, can also contribute to localized heating.
The scanner also produces loud noises, described as knocking, buzzing, or thumping, from gradient coils rapidly switching on and off. These changes cause coils to vibrate, generating sounds up to 130 decibels, so earplugs or headphones are provided.
Some individuals might also notice a temporary metallic taste, possibly due to magnetic field interaction with ionic currents. A tingling or twitching sensation, known as peripheral nerve stimulation (PNS), can also be felt, caused by rapidly changing magnetic fields stimulating nerves.
Preparing for and Managing Dizziness
Planning ahead can help minimize the likelihood or severity of dizziness during an MRI. Informing the MRI staff about any history of motion sickness, vertigo, or anxiety is a helpful first step; they may suggest strategies or a mild sedative.
During the scan, simple techniques can help manage potential dizziness. Keeping your eyes closed throughout the procedure can reduce visual disorientation. Focusing on slow, steady breathing can help maintain calm and control. Remaining as still as possible is important for image quality and to prevent exacerbating sensations of movement.
If dizziness becomes pronounced or uncomfortable, communicate immediately with the MRI technologist using the provided call button. They can often pause the scan or offer further assistance.
When to Consult a Healthcare Provider
While temporary dizziness during or immediately after an MRI is a known phenomenon and usually resolves quickly, certain situations warrant further medical attention. Contact your healthcare provider if dizziness is severe, persists for an extended period, or significantly disrupts your daily activities after the scan.
Seek medical advice if dizziness is accompanied by other concerning symptoms, such as:
Severe headache
Changes in vision
Weakness or numbness
Difficulty speaking
Problems with balance leading to stumbling
If you have pre-existing conditions causing dizziness or balance issues, discuss these with your referring physician and the MRI technologist before the scan to ensure appropriate precautions.