Magnetic Resonance Imaging (MRI) of the Internal Auditory Canal (IAC)

What is Magnetic Resonance Imaging (MRI) of the Internal Auditory Canal (IAC)?

Magnetic resonance imaging (MRI) of the internal auditory canal (IAC) is a non-invasive, painless diagnostic imaging procedure that uses using radio waves and a strong magnetic field to create detailed images of the bony canal that transmits nerves and blood vessels from the base of the brain to the inner ear.

How does an MRI Work?

MRI scanning involves the use of radio waves that temporarily realigns hydrogen atoms in the body without causing any chemical changes. As the hydrogen atoms return to their normal position, they emit varying amounts of energy depending on the type of tissue they are in. The MRI scanner captures the energy variation and creates detailed images based on this information.

Uses of MRI of the Internal Auditory Canal 

Magnetic resonance imaging of the internal auditory canal may be ordered by your doctor if you have hearing or balance problems which may be due to a possible disorder of the internal auditory canal such as:

• Abnormal structural changes such as narrowing or stenosis
• Infection or inflammatory changes
• Edema
• Schwannoma (soft tissue mass lesion)
• Meningioma (tumor that arises from the brain membrane)
• Lipoma (noncancerous fatty tissue tumor)
• Vascular lesions
• Cystic lesions

Preparation for MRI of the Internal Auditory Canal

• Inform your doctor regarding any health conditions, previous surgeries, implants or metal placed within your body, the likelihood of pregnancy, and allergies.
• Leave all jewelry at home. Wear loose-fitting comfortable clothing that does not contain any metal fasteners, or you may be asked to wear a hospital gown.
• Follow the eating and drinking restrictions given by your doctor.
• You can continue to take your regular medications unless otherwise specified.

Procedure for Magnetic Resonance Imaging of the Internal Auditory Canal

The procedure for magnetic resonance imaging of the internal auditory canal involves the following basic steps:

• You will be placed comfortably on a movable scanning table.
• Bolsters or straps may be used to help you remain still.
• A device containing coils that send and receive radio waves is placed around your head and ear region.
• You may be offered earplugs to avoid being distracted by the noises made by the MRI machine.
• An IV line will be placed into your arm to inject contrast material if required.
• The scanning table will be moved into the magnet of the MRI machine.
• The technologist will perform the examination from another room taking multiple pictures of the internal auditory canal and associated structures, each lasting several minutes.
• You will be required to remain as still as possible to obtain the clearest images.
• A microphone in the MRI machine allows you to talk to the technologist.
• The entire procedure will be completed within 45 minutes to an hour.

What happens after Magnetic Resonance Imaging of the Internal Auditory Canal? 

You can return to your routine activities and resume your normal diet immediately after the procedure. If sedation was provided to help you relax, you may have to wait until the effects of sedation wear off before returning to your routine activities. A radiologist or trained doctor will analyze the images and send the report to your doctor, who will share the results with you.

Risks of Magnetic Resonance Imaging of the Internal Auditory Canal

• The strong magnetic field produced by the MRI does not cause any harmful effects, except for malfunctioning of implanted devices which can distort the images.
• There may be an allergic reaction to contrast dye. These reactions are usually mild and can be easily controlled with medication.

Benefits of Magnetic Resonance Imaging of the Internal Auditory Canal

• Produces highly detailed images of the internal auditory canal and other cranial structures
• Detects abnormalities that may be obscured by bone with other imaging studies
• Virtually no side effects as there is no exposure to harmful radiation