MRI Magnetic Resonance Imaging

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					           MRI
Magnetic Resonance Imaging
      Jennifer and Janelle
           Anatomy
                     History
   MRI is based on a physics phenomenon
    discovered in the 1930s, called nuclear magnetic
    resonance or NMR, in which magnetic fields and
    radio waves cause atoms to give off tiny radio
    signals.
   The 2003 Nobel Prize in Physiology or Medicine
    was awarded to Paul C Lauterbur and Peter
    Mansfield for their discoveries concerning
    magnetic resonance imaging.
                 Background
 MRI   is primarily a medical imaging technique
  most commonly used in radiology to visualize the
  structure and function of the body.
 MRI provides much greater contrast between the
  different soft tissues of the body than computed
  tomography (CT) does, making it especially useful
  in neurological (brain), musculoskeletal,
  cardiovascular, and oncological (cancer) imaging.
Background cont.
        • MRI has been in use for
          little more than 30 years
          (compared with over 110
          years for X-ray
          radiography). The first
          MR Image was published
          in 1973 and the first study
          performed on a human
          took place on July 3,
          1977.
Uses/Technique
       Organs of the chest,
       abdomen and pelvis—
       including the heart, liver,
       biliary tract, kidney, spleen,
       and pancreas and adrenal
       glands.
       Pelvic organs including the
       reproductive organs in the
       male (prostate and testicles)
       and the female (uterus,
       cervix and ovaries).
Uses/Techniques cont.
                 Pelvic and hip bones
                 Blood vessels (MR
                  Angiography)
                 Breasts
                 Helps diagnose
                  conditions such as:
                  tumors, coronary artery
                  disease, heart
                  problems, abnormalities
                  of the heart, diseases of
                  the liver
                 Organs
                 Bones
             How It Works
• You will be positioned on the moveable
  examination table
• Straps may be used to help you stay still and
  maintain position
• Small devices that contain coils capable of
  sending and receiving radio waves may be
  placed around the area of the body being
  studied.
            How It Works cont.
   If a contrast material will be used in the MRI exam, a
    nurse will insert and IV into a vein in your hand or
    arm.
   You will be moved into the magnet of the MRI and
    the radiologist will leave the room while the
    procedure is done.
   When the examination is completed you may be
    asked to wait until the technologist checks the
    images.
   The IV will be removed.
   Generally includes multiples runs, some of which
    may last several minutes.
   The entire exam is usually completed within 45
    minutes.
Benefits
           • Does not involve
             exposure to radiation.
           • More likely to identify
             and characterize
             abnormalities than any
             other imaging method.
           • Proven valuable in
             diagnosing cancer,
             heart disease, and
             muscular abnormalities.
Benefits

    • Less likely to produce
      an allergic reaction.
    • Provides a fast
      noninvasive alternative
      to x-ray angiography
      for diagnosing
      problems of the heart
      and blood vessels.
    • Allows doctors to
      assess the biliary
      system noninvasively
      and without contract
      injection.
Risks

   • Poses almost no risk to
     the average patient.
   • If sedation is used
     there are risk of
     excessive sedation.
   • Medical devices that
     contain metal may
     malfunction or cause
     problems.
For the Patients
           May be asked to wear a
            gown during exam.
           Guidelines to eating may
            vary.
           Take normal medications
            daily.
           Some MRI’s may require
            the patient to swallow
            contrast material or
            receive an injecgtion.
For the Patient cont.
           •   The radiologist should
               know if you have any
               health problems, or if
               you may be pregnant.
           •   No jewlery, hair pins,
               removable dental work,
               pocket knifes, or body
               piercing.
           •   You may have metal
               implants, a pacemaker,
               ear implant, and/or
               brain aneurysm clamps.
Procedure

      The magnetic field is
       produced by passing an
       electric current through
       wire coils in most MRI
       units. Other coils,
       located in the machine
       and in some cases,
       placed around the part
       of the body being
       imaged, send and
       receive radio waves,
       producing signals that
       are detected by the
       coils.
              Procedure cont.
• A computer then processes the signals and
  generates a series of images each of which shows
  a thin slice of the body. The images can then be
  studied from different angles by the interpreting
  physician.
• Overall, the differentiation of abnormal (diseased)
  tissue from normal tissues is often easier with
  MRI than with other imaging modalities such as x-
  ray, CT and ultrasound.
                        Physics
• The body is mainly composed of water molecules which
  each contain two hydrogen nuclei or protons. When a
  person goes inside the powerful magnetic field of the
  scanner these protons align with the direction of the field.
• A second radiofrequency electromagnetic field is then
  briefly turned on causing the protons to absorb some of its
  energy. When this field is turned off the protons release
  this energy at a radiofrequency which can be detected by
  the scanner. The position of protons in the body can be
  determined by applying additional magnetic fields during
  the scan which allows an image of the body to be built up.
  These are created by turning gradients coils on and off
  which creates the knocking sounds heard during an MR
  scan.
             Physics cont.
• Diseased tissue, such as tumors, can be detected
  because the protons in different tissues return to
  their equilibrium state at different rates. By
  changing the parameters on the scanner this
  effect is used to create contrast between different
  types of body tissue.
• MRI is used to image every part of the body, but
  is particularly useful in neurological conditions,
  disorders of the muscles and joints, for evaluating
  tumors and showing abnormalities in the heart
  and blood vessels.
Pictures
Works Cited
• http://en.wikipedia.org/wiki/Magn
  etic_resonance_imaging
• http://inventors.about.com/od/mstarti
  nventions/a/MRI.htm
• http://www.radiologyinfo.org/en/i
  nfo.cfm?pg=bodymr#part_two
      What does MRI stand for?
•   A) Magnets Rebel Inside
•   B) Maggots really icky
•   C) Magnetic Resonance Imaging
•   D) My Resource imaging
Which of the following is not
what MRI is used to look at?

•   A)   Bones
•   B)   Hair
•   C)   Your friend
•   D)   Tissue
      True or False: You are permitted to wear
    jewelry and hair pins during the procedure?

• A) True
• B) False
      Which of the following is a
         Benefit of MRI’s?
•   A) You will not be cured
•   B) Your cat will die
•   C) No exposure to radiation
•   D) your hair will fall out
   Which of the following can
determine abnormal from normal
         tissue easiest?
•   A)MRI
•   B)CT
•   C)X-Ray
•   D)Ultrasound

				
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posted:10/25/2011
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