Magnetic Resonance Imaging

Salem Radiology’s MRI center located at 31 Stiles Road in Salem, NH, offers MRI imaging that provides patients with exceptional comfort. For more information about MRI services, call 603-893-4352.

The Basics of an MRI

Magnetic Resonance Imaging, or MRI is an advanced and state-of-the-art diagnostic test that produces clear images of the human body without the use of X-rays. This technology enables physicians to detect developing diseases or abnormalities earlier than ever before. MRI uses a powerful but harmless magnetic field and radiowaves- the kind that transmit your favorite radio station. The combination of radiowaves and the magnetic field produces detailed images of body structures such as the brain, the spine, and other vital organs.

How does an MRI scan work?

The human body is made up of millions of magnetic atoms. When placed in a magnetic field, these atoms line up with the field, much like a compass points to the North Pole. Radiowaves, when tuned to a specific frequency, tip these tiny magnets away from the magnetic field. As they gain energy, they tip. When the radiowaves 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 the computer, which performs millions of calculations to produce an image for diagnosis.

For certain studies, the injection of a contrast agent into the patient may be necessary to help better visualize the area being examined. Unlike contrast agents used in other radiology studies, MRI contrast agents do not contain iodine and therefore rarely cause allergic reactions or side effects.

MRI Patient Preparation

Before having a contrast injection, please tell your doctor, nurse, and/or MRI technologist if you:
• are allergic to any medicine, either prescription or non-prescription
• are pregnant
• are breast-feeding
• have any other medical conditions, especially allergies or a history of asthma, kidney disease, diabetes, or heart disease.

You should not take an MRI if you have any of the following:
• certain cerebral aneurysm clips (magnetic)
• certain heart valves
• cochlear implants
• metal filings in the eye
• pacemaker/defibrillator

Be sure to bring previous X-rays applicable to the exam. The radiologist may want to review them (For example, if you are having an MRI of the knee, please bring any previous X-rays of your knee).

It isn’t necessary to refrain from eating and drinking- your physician can help guide you through the preparation. You may take any medication that you are currently taking, as it is not necessary to stop taking it prior to the exam. In fact, the exam may be much more comfortable if you continue taking your medication.

If you think you may be claustrophobic, ask your doctor to prescribe medication prior to the exam. If you do receive medication, please bring someone with you who will be able to drive you home, as the medication will make you unsuitable to drive.

Also, please remember to bring a copy of your insurance card with you.

What can I expect from an MRI?

You will be asked a series of questions concerning your surgical and occupational background. If this history includes metal work or metal implants, please be sure to tell the technologist prior to your exam, as preliminary X-rays may need to be taken.

Although MRI is a very advanced medical technique, the MRI scan is probably one of the easiest and most comfortable exams one 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 magnet is open on both ends. The technologist will stay in contact with you throughout the 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 can distort the image.

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

Length of an MRI Exam

The average exam time takes 20-45 minutes, depending on what your doctor has ordered.