MAGNETIC RESONANCE IMAGING 1

MAGNETIC RESONANCE IMAGING – Indications, Advantages, Nursing Consideration, Contraindications, Interfering Factors, Client Preparation, Procedure and Post-Procedural Care

Magnetic resonance imaging (MRI) is a noninvasive test that employs a powerful magnet, radio waves and a computer to help diagnose respiratory disorders by providing high-resolution, cross sectional images of lung structures and by tracing blood flow. MRI’s great advantage is its ability to see through bone and to delineate fluid-filled soft tissue in great details, without using ionizing radiation or contrast media

INDICATIONS

  • It provides valuable information about body’s biochemistry by placing the client in a magnetic field
  • MRI is based on how hydrogen atoms behave when they are placed in a magnetic field and then distributed by radio frequency signals

ADVANTAGES

  • MRI provides better contrast between normal tissues and pathogenic tissues
  • It provides a natural contrast from other tissues to the blood vessels when using MRI
  • It is possible to image the transverse, sagittal and coronal planes directly with MRI

NURSING CONSIDERATION

  • Instruct the client to remove all jewelry and taken everything out of his packet
  • Emphasize that there must be no metal may demagnetize the magnetic strip on a credit card to stop a watch from ticking
  • Make sure the client has notified his doctor if he has any metal inside his body, such as a pacemaker, orthopedic pins or discs and bullets or sharper fragments
  • Inform the client he will asked to lie on a table slides into an 8’ (2.4 m) tunnel inside the magnet
  • Advise him to breathe normally but not to talk or move during the test to avoid distorting the results
  • Inform him the test usually takes 15-30 minutes
  • Warn the client that the machinery will be noisy with sounds ranging from an incessant ping to a loud bang
  • The client may feel claustrophobic or board. Encourage him to relax and to concentrate on breathing or a favorite subject or image

CONTRAINDICATIONS

  • Clients who are extremely obese
  • Clients who are pregnant, because the long-term effects of MRI are not known at this time
  • Clients who are confused and agitated
  • Clients who are claustrophobic if using an enclosed scanner
  • Clients who are unstable and require continuous life support equipment, because monitoring equipment cannot be used inside the scanner room
  • Clients with implantable metal objects such as pacemaker, infusion pumps, aneurysm clips, inner ear impacts and metal fragments in one or both eyes, because the magnet may move the object within the body and injure the client

INTERFERING FACTORS

Movement during the scan causes artifacts on MRI

CLIENT PREPARATION

  • Explain the procedure to the patient
  • Inform the client that there is no exposure to radiation
  • Obtain informed consent if required by the institution
  • Inform the client that he or she can drive without assistance after the procedure
  • Tell parents of young client’s that they may read or talk to a child in the scanning room during procedure, because no risk of radiation from the procedure exists
  • If possible, show the client a picture of the scanning machine and encourage verbalization of anxieties. Some client’s may experience claustrophobia. Antianxiety medications may be helpful for those with mild claustrophobia
  • Instruct the client to remove all metal objects (e.g., dental brides, jewelry, hair clips, belts, credit cards) because they will create artifacts on the screen. The magnetic field can damage watches and credit cards
  • Inform the client that he or she will be required to remain motionless during this study. Any movement can cause artifacts on the screen
  • Inform the client that during the procedure he or she may hear a thumping sound; earplugs are available if the client wishes to use them
  • Inform the client that no fluid or food restrictions are necessary before MRI
  • For comfort, instruct the client to empty the bladder before the rest

PROCEDURE

  • The client lies on the flat form that slides into a tube containing the doughnut shaped magnet
  • The client is instructed to lie very still during the procedure
  • During the scan, the client can talk to and hear the staff via microphone or earphones placed in the scanner
  • A contrast medium called gadolinium (magnevist) has been approved by the US Food and Drug Administration. This is a paramagnetic enhancement agent that crosses the blood-brain barrier. It is especially useful for distinguishing edema from tumors
  • This procedure is performed by qualified radiological technologist in approximately 30 to 90 minutes
  • Inform the client that the only discomfort associated with this procedure may be lying still on a surface and possible tingling sensation in teeth containing metal filling. Also, an injection may be needed for administration of magnevist

POST-PROCEDURAL CARE

Inform the client that no special post-procedural care is needed

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