Highfield MRI

What is magnetic resonance imaging (MRI)?
It’s a way to look inside the body without using X-rays.

MRI can produce 2-or 3-dimensional images.
It uses:
• A large magnet
• Radio waves
• A computer.
The magnet is large enough to surround the patient. A computer uses information created by the magnet and radio waves to form detailed images of the body’s interior.

MRI pictures are precise.
MRI can often give health-care providers as much information as they would get from looking directly at the body’s tissues and organs.

For this reason, MRI may reduce the need for certain diagnostic surgeries. It can also lead to early detection and treatment of disease.

MRI has many uses.
MRI “sees” right through bone, and clearly pictures soft tissue. MRI is especially valuable for helping to diagnose:

Brain and nervous system disorders
These include:
• Multiple sclerosis
• Tumors
• Certain spinal conditions and diseases
• Hydrocephalus (abnormal fluid in the skull)
• Stroke.

Cancer
MRI may be used to detect cancer in some organs and tissues.

Musculoskeletal problems
MRI can detect injuries, disorders and diseases affecting tendons, ligaments, cartilage and bone marrow.

How to prepare for an MRI scan

At the scanning site:
• You’ll discuss your medical history.
• You’ll be told about the scanning procedure. You may need to sign a consent form.
• You must removed all metallic objects before you are scanned, including jewelry, watches, glasses, clothing with zippers, nonpermanent dentures, hearing aids and credit cards. Ask about cosmetics, braces or permanent bridges. (Tooth fillings are usually not a problem.)
• You may be asked to change into scrubs.
• You may be checked with a metal detector.
• You may be given an injection containing a contrast agent (a substance that improves the quality of certain images).
• Go to the bathroom before the scan so you will be comfortable during the exam.
• Ask if music or earplugs are available. (MRI scans can be noisy.)
• If you are very nervous, your family doctor may precribe a sedative for you.

The scan procedure
is painless-you will not feel the magnetic field or radio waves.

Before the scan, the technologist will help position you on the scanning table. Generally, you will lie on your back. A small coil may be attached to the part of the body being scanned-this device helps improve image quality.

As the scan begins, the scanning table slides into the interior of the giant magnet.

During the exam, try to relax and stay still so the images do not blur. Although you will not feel anything you will hear some knocking or thumping sounds.

When the scan is finished, the images will be reviewed for quality. If more images are needed, they’ll usually be taken right away. If you were sedated, have a family member drive you home.

Questions and answers

Can pregnant women have MRI scans?
Since the long-term effects of MRI are not fully understood, pregnant women are usually not advised to have MRI scans. However, MRI may be recommended in certain cases.

What is an open MRI scanner?
It’s an MRI machine that’s open at the ends and side(s). This lets patients see and talk with loved ones and technologists at all times.

Open MRI isn’t always recommended or available. It’s usually reserved for patients who are claustrophobic or large, or for young children. It can also be used to show images for a needle biopsy.

Can people with metal implants be scanned?
In general, an MRI scan cannot be done if a person’s body contains:
• An implanted electronic device, such as a cardiac pacemaker.
• A metal object that contains iron.
If you have any metal implants, tell your health-care provider. He or she will determine if you can have an MRI scan.

How long does a scan take?
Scanning times range widely, from about 20 minutes to 90 minutes.