Mri Presentation

Magnetic Resonance Imaging: Is It Worth It?

Background  History of the M.R.I. What is an M.R.I. Machine?  Basics of what the machine is Uses of the M.R.I.  Medical problems that an M.R.I. can detect Magnetic  How the magnet in the machine works Resonance How the picture is created by radio waves Imaging  Types of images that can be created M.R.I. Images  Pictures created in an M.R.I. Advantages  Why an M.R.I. Can be better than x-rays, CAT scans Disadvantages Risks associated with an M.R.I. Getting an M.R.I. What to expect during the exam Conclusion  An M.R.I. Has more advantages than disadvantages

1970 – Dr. Damadian, Dr. Minkoff, and Dr. Goldsmith begin building the first M.R.I. machine. 1977 – On July 3rd, the first M.R.I. ever performed on a human occurred. It took 5 hours to produce poor images. 1990s – The M.R.I. is widely used for medical diagnoses.

Original Design 

An M.R.I. machine is typically shaped like a long thin tube: 7h x 7w x 10L There is a powerful magnet running from front to back The body part being examined is placed in the exact center of this magnetic field (the “isocenter”) It can make a 2-D or a 3-D map of body tissues

Diagnose tumors, tendonitis, stroke, multiple sclerosis, and infections in the brain, spine, or joints Visualize torn ligaments or shoulder injuries, brain trauma (bleeding or swelling) Evaluate bone tumors, cysts, bulging/herniated discs, structure of the heart or aorta, or masses in soft tissues It is preferred to radiology in the evaluation of back pain and diagnosis of back problems.

Spine MRI Shoulder MRI 

The M in M.R.I. stands for “magnetic.” The magnet used in an M.R.I. is 30,000 times stronger than the magnetic field of the earth and can pull in all metal objects within several yards of it. The magnet causes the nuclei of hydrogen atoms within the body (which normally point in different directions) to line up in a parallel formation.

MRI magnet pulling in a large metal object 

The R in M.R.I. stands for “resonance.” The M.R.I. machine emits a radio frequency pulse toward the body region being examined, where the magnet has caused the hydrogen atoms of the water in the body to align. When the radio waves hit the hydrogen atoms, they fall out of parallel formation. As the hydrogen atoms fall back into alignment, they emit a radio signal, which is detected by a computer.  Affected by magnet In random 

The images created in an M.R.I. can be in any plane: axial, coronal, or sagittal. Axial

Coronal Sagittal 

It creates cross-sectional images or slices of a body part: think of the body part as a loaf of bread, and each M.R.I. image is a slice of it.

 Abdominal MRI

Knee MRI 

It can create images in any plane and in many dimensions that are more detailed than CAT scans. It does not involve radioactive material, like x-rays. It is safe, painless, and noninvasive. In patients that have had strokes, an MRI can detect what parts of the brain have been damaged/affected. CAT Scan

MRI 

You can’t get an M.R.I. if you have a pacemaker or if you are too overweight or pregnant or claustrophobic. An M.R.I. can’t always distinguish between tumors and other fluids, and CAT scans are better for patients with excessive bleeding. It is expensive to have an M.R.I. done because the machines are so expensive.

You will have to remove all metal objects from your body and pockets, because the magnet can pull objects off the body. You will have to lie completely still for the 20-90 minute exam so that the images aren’t distorted. The machine makes a loud, rhythmic thumping sound, but you may be given headphones so you can listen to music.

The M.R.I. can be used to make many medical diagnoses. Though there are a few risks and the cost can sometimes be prohibitive, the benefits of the M.R.I. outweigh the disadvantages, and the M.R.I. is more safe than other means of achieving the same result, so it is worth using.

Conlan, R. August 16, 2002 Magnetic Resonance Imaging http://beyonddiscovery.org/content/view.article.asp?a=129 Gould, T. “How MRI Works” http://electronics.howstuffworks.com/mri.htm Kuwana, E. October 17, 2003 MRI Nets Two for the 2003 Nobel Prize http://faculty.washington.edu/chudler/nobel03.html Radiological Society of North America April 25, 2003 Magnetic Resonance Imaging (MRI) of Body http://www.radiologyinfo.org/content/mr_of_the _body.htm Wellbery, C. February 1, 2004 Rapid MRI or Radiography for Low Back Pain? http://www.aafp.org/20040201/tips/8.html