Magnetic Resonance Imaging (MRI) in Neuroradiology

A magnetic resonance imaging scan uses magnetic waves to make pictures of the inside of the body.  Using a large magnet, radio waves and a computer, an MRI produces two-dimensional (2-D) and three-dimensional (3-D) pictures.

An MRI can evaluate any part of the body.  Neuroradiology deals primarily with MRI scans of the brain, neck and spine.

MRI exam are done for two major reasons:

•  To diagnose internal injuries or conditions
•  To monitor the effects of medications and treatments inside the body

You may not be able to have an MRI exam if you have any of the following in your body:

• Pacemaker
• Neurostimulator
• Ear implant
• Metal clips in your eyes
• Implanted port device
• Intrauterine device (IUD)
•  Metal plate, pins, screws or surgical staples
•  Metal clips from an aneurysm repair
• Retained bullets
• Any other large metal objects implanted in your body (tooth fillings and braces are usually not a problem)

You should tell the doctor or technician if your occupation involves work with metal fillings or particles.

Prior to Procedure

In the days leading up to your MRI exam:

• You may be asked to avoid using hair gel, spray, lotions, powders and cosmetics before your MRI
• If your doctor prescribes a sedative:

o       Arrange for a ride to and from the exam

o       Do not ear or drink at least 4 hours before the exam

o       Take it the sedative 1 – 2 hours before the exam, or as directed

• If you have not been prescribed a sedative, ear or drink normally, unless your doctor or the technician tells you otherwise.

Once at the MRI center:

• You will be asked about:

o       Medical history

o       Medications you take

o       Medication allergies

o       If you are pregnant or trying to get pregnant

o       If you have any metal objects in your body

• You will remove any metal containing objects, such as jewelry, hairpins, hearing aids, glasses, wigs (with metal clips) and non-permanent dentures
•  An x-ray may be taken beforehand if there is doubt as to whether there are metal objects in your body
•  You will also remove all objects from your pockets including your wallet, watch or timepiece

During the Procedure

If contrast dye is needed, it is injected into a vein.  You will be positioned on a special moveable table with your head, neck or back inside the MRI scanner, which is shaped like a cylinder.  You may be given earplugs or stereo headphones to wear due to the loud banging noise the MRI machine makes during the exam. 

Anesthesia

None, unless you are claustrophobic, in which case your doctor can prescribe a sedative to take before the exam. 

Description  of the Procedure

You lie very still on a sliding table.  Depending on your medical condition, you may have monitors placed to keep track of your pulse, breathing, etc.  The table is slid into the MRI’s narrow, enclosed cylinder (unless it is an “Open” MRI).  The MRI technician leaves the room, and each of the MRI sequences is performed.  The technician gives you any necessary directions, such as to hold your breath momentarily, through the intercom.  You are able to talk with the technician through the intercom during the exam, so, if you are in pain, frightened or concerned, you are able to communicate immediately.

 If a contrasting dye (called Gadolinium) is needed, a small IV needle is inserted into your hand or arm before you are slid into the MRI machine.  First, a saline solution is dripped into your vein to prevent your blood from clotting.  Then, usually two-thirds of the way through the exam, the Gadolinium is injected.

 When the MRI exam is complete, you are taken out of the MRI scanner.  The IV will be removed (if you had contrast), and you will dress and wait in the waiting room.

After the Procedure

You will be asked to wait until the MRI images are checked to determine if more images are needed.  If so, more images will be taken at that time.

How long will it take?

40 – 60 minutes

Will it hurt?

An MRI exam is painless.  If you have contrast dye injected, there may be a momentary stinging when the IV needle is inserted.  You might feel a slight cooling feeling when the Gadolinium is injected. 

If you are claustrophobic, you may find this exam very difficult.  A conventional MRI machine is a very small, enclosed cylindrical tube.  You will need to lie very still in it for an extended period of time.  However, you can ask your doctor to prescribe a sedative for the exam.  Also, ask your doctor about having the exam done in an “Open” MRI machine.  An open MRI is much larger that a conventional MRI and is usually open on the sides and in the front and back.  “Open” MRI generally does not produce satisfactory images for brain cancer follow-up or for disease of the eyes and ears.  Certain diseases of the spine are seen best on the MRI when a conventional MRI scanner is used.

Possible Complications

An allergic reaction to contrast dye (Gadolinium) can occur if it is used. 

Average Hospital Stay

None

Postoperative Care

If you took a sedative, do not drive, operate machinery or make important decisions until after the sedative wears off completely.  If you are breastfeeding and receive contrast dye during the MRI, wait at least 24 hours after the exam before breastfeeding again.

After the exam, a radiologist will analyze the images and send a report to your doctor.  Your doctor will discuss the results with you.

It is essential for you to monitor your recovery once you leave the health care facility.  In this way, you can alert your doctor to any problems right away.  If you received contrast dye, call your doctor immediately if any of the following occurs:

• Hives
• Itching
• Nausea
• Swollen or itchy eyes
• Tightness of the throat
• Trouble breathing