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Advantages and Disadvantages of MRI

Why would your doctor order an MRI? Because the only way to see inside your body any better is to cut you open. MRI is ideal for:
  • Diagnosing multiple sclerosis (MS)
  • Diagnosing tumors of the pituitary gland and brain
  • Diagnosing infections in the brain, spine or joints
  • Visualizing torn ligaments in the wrist, knee and ankle
  • Visualizing shoulder injuries
  • Diagnosing tendonitis
  • Evaluating masses in the soft tissues of the body
  • Evaluating bone tumors, cysts and bulging or herniated discs in the spine
  • Diagnosing strokes in their earliest stages
These are but a few of the many of reasons to perform an MRI scan.
The fact that MRI systems do not use ionizing radiation is a comfort to many patients, as is the fact that MRI contrast materials have a very low incidence of side effects. Another major advantage of MRI is its ability to image in any plane. CT is limited to one plane, the axial plane (in the loaf-of-bread analogy, the axial plane would be how a loaf of bread is normally sliced). An MRI system can create axial images as well as images in the sagitall plane (slicing the bread side-to-side lengthwise) and coronally (think of the layers of a layer cake) or any degree in between, without the patient ever moving. If you have ever had an X-ray, you know that every time they take a different picture, you have to move. The three gradient magnets discussed earlier allow the MRI system to choose exactly where in the body to acquire an image and how the slices are oriented.

MRI does have drawbacks, however. For example:
  • There are many people who cannot safely be scanned with MRI (for example, because they have pacemakers), and also people who are too big to be scanned.
  • There are many claustrophobic people in the world, and being in an MRI machine can be a very disconcerting experience for them.
  • The machine makes a tremendous amount of noise during a scan. The noise sounds like a continual, rapid hammering. Patients are given earplugs or stereo headphones to muffle the noise (in most MRI centers you can even bring your own cassette or CD to listen to). The noise is due to the rising electrical current in the wires of the gradient magnets being opposed by the main magnetic field. The stronger the main field, the louder the gradient noise.
  • MRI scans require patients to hold very still for extended periods of time. MRI exams can range in length from 20 minutes to 90 minutes or more. Even very slight movement of the part being scanned can cause very distorted images that will have to be repeated.
  • Orthopedic hardware (screws, plates, artificial joints) in the area of a scan can cause severe artifacts (distortions) on the images. The hardware causes a significant alteration in the main magnetic field. Remember, a uniform field is critical to good imaging.
  • MRI systems are very, very expensive to purchase, and therefore the exams are also very expensive.
 The almost limitless benefits of MRI for most patients far outweigh the few drawbacks. 

Note: The information on this Web site is provided as general health guidelines and may not be applicable to your particular health condition. Your individual health status and any required medical treatments can only be properly addressed by a professional healthcare provider of your choice. Remember: There is no adequate substitution for a personal consultation with your physician. Neither Corona Regional Medical Center, or any of their affiliates, nor any contributors shall have any liability for the content or any errors or omissions in the information provided by this Web site.
 
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