MRI

MRI Exams at Central Louisiana Surgical Hospital


What is MRI and how does it work?

Magnetic resonance imaging, or MRI, is a way of obtaining very detailed images of organs and tissues throughout the body without the need for x-rays or "ionizing" radiation. Instead, MRI uses a powerful magnetic field.  For this procedure, the patient is placed within the MR scanner—typically a large, tunnel or doughnut-shaped device that is open at both ends.

An MRI exam causes no pain, and the magnetic fields produce no known tissue damage of any kind. The MR scanner may make loud tapping or knocking noises at times during the procedure; using earplugs prevents problems that may occur with this noise. You will be able to communicate with the MRI technologist at any time using an intercom system or by other means.

What is MRI used for?

MRI has become the preferred procedure for diagnosing a large number of potential problems or abnormal conditions in many different parts of the body. In general, MRI creates pictures that can show differences between healthy and unhealthy tissues.

How safe is MRI?

To date, over 150 million patients have had MRI examinations. Every year, approximately 10 million patients undergo MRI procedures. MRI has been shown to be extremely safe as long as proper safety precautions are taken. In general, the MRI procedure produces no pain and causes no known short-term or long-term tissue damage of any kind.

The question of claustrophobia

Some patients who undergo MRI examinations may feel confined, closed-in, or frightened. Perhaps one in twenty may require a sedative to remain calm. If you feel like this could be an issue for you please discuss this in advance with your physician. Our MRI technologist will permit a relative or friend to be present in the MR system room for the duration of your exam to help with feelings of claustrophobia.  Our staff of highly trained MRI technologist will work with you to make your experience here comfortable and enjoyable.

Pregnancy and MRI

If you are pregnant or suspect you are pregnant, you should inform the MRI technologist and/or radiologist during the screening procedure before the MRI examination. In general, there is no known risk of using MRI in pregnant patients. However, MRI is reserved for use in pregnant patients only to address very important problems or suspected abnormalities. In any case, MRI is safer for the fetus than imaging with x-rays or CT.

You should inform your technologist if you are breast-feeding at the time of a scheduled MRI study if an MRI contrast agent has been ordered. One option under this circumstance is to pump breast milk before the study, to be used until injected contrast material has cleared from the body, which typically takes about 24 hours.

How should I prepare for my MRI exam?

You will typically receive a gown to wear during your MRI examination. Before entering the MR system room, you and any accompanying friend or relative will be asked questions regarding the presence of implants and will be instructed to remove all metal objects from pockets and hair. Additionally, the accompanying individual will need to fill out a screening form to ensure that he or she may safely enter the MR system room.

If you are scheduled to have an injection of Contrast during your MRI exam you will need to remain NPO (without food or drink) for 4 hours prior to you scheduled exam time.  You can take all medications prior to your exam.  Diabetic patients may be asked to withhold certain types of medications after an injection.
After preliminary screening, the patient must undergo comprehensive screening in preparation for the magnetic resonance (MR) procedure. Comprehensive patient screening involves the use of a printed form to document the screening procedure, a review of the information on the screening form, and a verbal interview to verify the information on the form and to allow discussion of concerns the patient may have. An MR-safety trained healthcare worker must conduct this aspect of patient screening.

Items that may create a health hazard or other problem during an MRI exam include:

  • Cardiac pacemaker or implantable defibrillator
  • Catheter that has metal components that may pose a risk of a burn injury
  • A ferromagnetic metal clip placed to prevent bleeding from an intracranial aneurysm
  • An implanted or external medication pump (such as that used to deliver insulin or a pain-relieving drug)
  • A cochlear (inner ear) implant
  • A neurostimulation system
  • Items that need to be removed by patients and individuals before entering the MR system room include:
  • Purse, wallet, money clip, credit cards, cards with magnetic strips
  • Electronic devices such as beepers or cell phones
  • Hearing aids
  • Metal jewelry, watches
  • Pens, paper clips, keys, coins
  • Hair barrettes, hairpins
  • Any article of clothing that has a metal zipper, buttons, snaps, hooks, underwires, or metal threads
  • Shoes, belt buckles, safety pins

Objects that may interfere with image quality if close to the area being scanned include:

  • Metallic spinal rod
  • Plates, pins, screws, or metal mesh used to repair a bone or joint
  • Joint replacement or prosthesis
  • Metal jewelry including those used for body piercing
  • Some tattoos or tattooed eyeliner (these alter MR images, and there is a chance of skin irritation or swelling; black and blue pigments are the most troublesome)
  • Bullet, shrapnel, or other type of metal fragment
  • Metallic foreign body within or near the eye (such an object generally can be seen on an x-ray; metal workers are most likely to have this problem)
  • Dental fillings (while usually unaffected by the magnetic field, they may distort images of the facial area or brain; the same is true for orthodontic braces and retainers)

MRI and Contrast

For some MRI studies, a contrast agent called “gadolinium” may be injected into a vein to help obtain a clearer picture of the area being examined. At some point during the examination, a technologist will slide the table out of the scanner in order to inject the contrast agent. This is typically done through a small needle connected to an intravenous line that is placed in an arm or hand vein. Like contrast agents used in x-ray studies, MRI contrast agents can cause allergic reactions.  It is known that certain patients may be unable to filter the gadolinium out of their systems, a recently identified disorder called Nephrogenic Systemic Fibrosis / Nephrogenic Fibrosing Dermotherapy (NSF/NFD) may develop.  Your trained Radiologic technologist will screen all patients for any identifying factors and take all necessary precautions.

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