Nursing Responsibilities: MRI Pre and Post Procedure

What is MRI (Magnetic Resonance Imaging) 

It is an imaging test that uses powerful magnets and radio waves to create images or pictures of your body in detail.  It  has become the preferred procedure for diagnosing a large number of potential problems in many different parts of the body. It does not use radiation (x-rays).  It is also called Nuclear magnetic resonance (NMR) imaging.

Single MRI images are called slices. The images can be stored on a computer or printed on film. One exam produces dozens or sometimes hundreds of images.

An MRI exam causes no pain. If you have difficulty lying still or are very nervous, you may be given a medicine to relax you. Too much movement can blur MRI images and cause errors.

The table may be hard or cold, but you can request a blanket or pillow. The machine produces loud thumping and humming noises when turned on. You can wear ear plugs to help reduce the noise.

An intercom in the room allows you to speak to someone at any time. Some MRIs have televisions and special headphones that you can use to help the time pass.

How the test is performed?

• You may be asked to wear a hospital gown or clothing without zippers or snaps (such as sweatpants and a t-shirt). Certain types of metal can cause blurry images.
• You will lie on a narrow table, which slides into a large tunnel-shaped scanner.
• Some exams require a special dye (contrast). Most of the time, the dye be given  through a vein (IV) in your hand or forearm before the test. The dye helps the radiologist see certain areas more clearly.
• Small devices, called coils, may be placed around the head, arm, or leg, or other areas to be studied. These help send and receive the radio waves, and help the quality of the images.
• During the MRI, the person who operates the machine will watch you from another room. The test lasts about 30-60 minutes, but may take longer.

Nursing Responsibilities:

a.  Before the procedure

1. Patient may be asked not to eat or drink anything for 4 - 6 hours before the scan.
2. Asked patient if they are afraid of close spaces or claustrophobia and inform the doctor.  Patient may be given a medicine to help them feel sleepy and less anxious, or the doctor may suggest an "open" MRI, in which the machine is not as close to the body.
3. Before the test, asked the patient if they have the following:

• Artificial heart valves
• Brain aneurysm clips
• Heart defibrillator or pacemaker
• Inner ear (cochlear) implants
• Kidney disease or dialysis (patient may not be able to receive contrast)
• Recently placed artificial joints
• Vascular stents
• Worked with sheet metal in the past (patient may need tests to check for metal pieces in their eyes) 

      4.  Asked patients to remove the following:

• Items such as jewelry, watches, credit cards, and hearing aids - may be damaged.
• Pens, pocketknives, and eyeglasses - may fly across the room.
• Pins, hairpins, metal zippers, and similar metallic items - can distort the images.
• Removable dental work should be taken out just before the scan.

       Because the MRI contains strong magnets, metal objects are not allowed into the room with the MRI scanner.

It is important to inform the health care provider of any pregnancy or suspected pregnancy prior to the procedure.

b.  During the procedure

• Patient will be asked to remain perfectly still during the time the imaging takes place, but between sequences some minor movement may be allowed. The MRI Technologist will advise accordingly.
• When MRI procedure begins, patient may breathe normally, however, for certain examinations it may be necessary for you to hold your breath for a short period of time. 
• Monitoring is indicated to patients who are great potential for change in physiologic status (respiratory rate, oxygen saturation, temperature, heart rate and  blood pressure) during the procedure or whenever a patient requires observations of vital physiologic parameters due to an underlying health problem.
• Monitoring is imperative to patients who are using sedative or anesthesia to ensure patient safety

     Patients that require monitoring and support during MRI procedures. 

• Physically or mentally unstable patients.
• Patients with compromised physiologic functions.
• Patients who are unable to communicate.
• Neonatal and pediatric patients.
• Sedated or anesthetized patients.
• Patients undergoing MR-guided interventional procedures.
• Patients who may have a reaction to an MRI contrast agent.
• Critically ill or high-risk patients.

c.  After the procedure

There is no recovery time, unless you were given a medicine to relax. After an MRI scan, you can resume your normal diet, activity, and medications.

If patient is sedated, patient is transferred to the recovery room for continue monitoring. Especially important for pediatric patients because certain medications have relatively long half-lives (e.g., chloral hydrate, pentobarbitol, etc.). 

Prior to allowing the patient to leave the MRI facility, the patient should be alert, oriented, and have stable vital signs. A responsible adult should accompany the patient home. Written instructions that include an emergency telephone number should be provided to the patient.

Risks

It does not use radiation (x-rays). No side effects from the magnetic fields and radio waves have been reported.

The strong magnetic fields created during an MRI can cause heart pacemakers and other implants not to work as well. The magnets can also cause a piece of metal inside your body to move or shift.

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 nurse or 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. A saline solution will drip through the intravenous line to prevent clotting until the contrast material is injected at some point during the exam. Unlike contrast agents used in x-ray studies, MRI contrast agents do not contain iodine and, therefore, rarely cause allergic reactions or other problems.  However, gadolinium can be harmful to people with kidney problems who are on dialysis.