MRI (Magnetic Resonance Imaging)

What is Magnetic Resonance Imaging?

Magnetic Resonance Imaging, or MRI, is an advanced, state-of-the-art method which produces very clear pictures, or images, of the human body without the use of X-Rays.

NWH offers a high-definition MRI that uses magnetic and radio waves to visualize the structure and function of the body and provide detailed images in any plane. 

MRI services offered: Monitored sedation and Anesthesia Breast MRI LAVA -- Specialized Liver Imaging MR Angiography

MRI has much greater soft tissue contrast than Computed Tomography (CT) making it useful in neurological, musculoskeletal, cardiovascular and gynecological imaging.

NWH's MRI is accredited by the American College of Radiology (ACR). ACR certification recognizes consistency and excellence in imaging. 

How does MRI work?

The human body is made up of millions of atoms which are magnetic. When placed in a magnetic field, these atoms line up with the field, much like a compass points to the North Pole. Radio waves, tuned to a specific frequency, tip these tiny magnets away from the magnetic field. As they tip, they gain energy. When the radio waves are turned off, the atoms try to realign with the magnetic field, releasing the energy they gained as very weak radio signals. A powerful antenna picks up these signals and sends them to a computer, which performs millions of calculations to produce a black and white image for diagnosis.

The average MR scan takes 5-15 minutes, with a complete exam running 20-60 minutes. During this time, several dozen images may be obtained. These images assist us in making the best diagnosis possible and may even eliminate the need for biopsy or surgery.

The MR exam poses no risk to the average patient if appropriate safety guidelines are followed. You can never have an MRI if you have any of the following:

• Cardiac Pacemaker
• Implanted Cardiac Defibrillator
• Implanted Neurostimulator

If you have any questions regarding the MR exam, please be sure to discuss them with your doctor.

Note: If you have any implanted device card (IVC Filter, Joint Replacement etc…) please be sure to bring the card with you to your appointment, the MRI Technologist will need to see it.

Head and Neck

MRI gives very detailed pictures of the brain and spine. The image at right clearly shows structures in the normal head and neck. Air and hard bone do not give an MR signal so these areas appear black. Bone marrow, spinal fluid, blood and soft tissues like the brain vary in intensity from black to white depending on the amount of fat and water present in each tissue, and the machine settings used for the scan. The radiologist compares the size and distribution of these bright and dark areas to determine whether a tissue is healthy.

Body

Nearly every part of the body may be studied with MRI. Organs within the chest and abdomen, such as the heart, liver, bladder and kidneys can easily be seen. The image at right gives a very detailed view of the kidneys (arrows) and spine (dividing the image from top to bottom) in the lower back. The "tree-like" structures at the base of the spine are nerve roots.

Liver Acquisition with Volume Acceleration (LAVA) is a specialized liver imaging study used with MRI to overcome normal organ motion to provide for better abdominal image quality.

Bones and Joints

MRI is very sensitive to changes in cartilage and bone structure resulting from injury, disease or aging. The image at right is a normal knee as viewed from the side. The patella or "knee cap" is indicated by an arrow. Clear pictures such as these often provide information not available through other medical testing and may actually eliminate the need for exploratory surgery.

What Can You Expect During the MRI Exam?

Although MRI is a very advanced medical technique, the MRI exam is probably one of the easiest and most comfortable exams you may ever experience.

The technologist will simply ask you to lie down on a cushioned table which will automatically move into the magnet after you have been comfortably positioned for scanning. The technologist will leave the magnet room but you will be in constant contact with him or her throughout the entire exam.

When the MRI scan begins, you will hear a muffled thumping sound which will last for several minutes. Just relax-even take a nap-but try to lie as still as possible since any movement during this time will blur the picture.

Other than sound, you should experience no other sensation during scanning. When scanning is complete, the technologist will return to assist you off of the table.

For your pleasure, please feel free to bring your favorite music (iPod, MP3, CD or cassette) to listen to during the exam.

For Your Personal Safety:

If you are having an MRI examination, please inform your doctor or the technologist at the time of your exam if you have:

• a pacemaker
• a metal plate, pin or other metallic implant
• aneurysm clips
• an artificial heart valve
• ever been a metal worker
• an intrauterine device (IUD)
• ever been wounded during military service
• Be sure to tell us if you are pregnant or nursing.

Help Us Get a Good Picture of You:

Metallic objects often give a bright or blank spot in the picture. To help your doctor make the best diagnosis and to avoid wasting your time, please do not wear:

• hairspray
• make-up
• hairpins or barrettes
• a hearing aid
• eyeglasses
• jewelry
• any removable dental work

You may also want to avoid drinking coffee or other caffeinated beverages prior to scanning so you are able to lie quietly for several minutes at a time.

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