Below are Frequently Asked Questions from patients scheduled for a Magnetic Resonance Imaging (MRI) scan. If your question is not listed, please email the Physician Assistant, Jerri Payne:

Jerri.Payne@UTsouthwestern.edu, or call our office at (214) 645-2700.

Questions:

1.  When are you open? 

2.  How much radiation is involved in an MRI scan?

3.  How does MRI work?

4.  Who cannot have an MRI?

5.   Are there any known side effects?

6.  Is there any discomfort? (Will I feel anything?)

7.  What if I am claustrophobic?

8.  Will there be any needles or injections?

9.  What complications may occur because of the sedation required for the scan?

The Mary Nell and Ralph B. Rogers Magnetic Resonance Center is open Monday through Friday 7:30 AM to 6:00 PM. Phones lines are open from 8:00 AM to 5:00 PM. The Center is open on Saturdays from 8:00 AM to 4:00 PM for research patients only.

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Because an MRI scan uses a magnet and does not use X-ray or particle beams, an MRI scan produces no ionizing radiation.

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Magnetic Resonance Imaging (MRI) generates cross-sectional images of the human body by using Nuclear Magnetic Resonance (NMR). The process begins with the positioning of the imaged body in a strong, uniform magnetic field, which polarizes the nuclear magnetic moments of water protons by forcing their spins into one of two possible orientations . Then an appropriately polarized radio-frequency field, applied at resonant frequency, forces spin transitions between orientations . Those transitions create a signal (which is an NMR phenomenon) that can be detected by a receiving coil.

An MRI scanner applies the radio-frequency field as finely crafted pulses, which excite only protons whose resonant frequencies fall within a fairly narrow range. Applying magnetic-field gradients during the radio-frequency pulse creates resonant conditions for only the protons that are located in a thin, predetermined slice of the body. The image is received by the coil and the information is then analyzed by a computer through the use of certain mathematical formulas to composite an image of the slice, that are then displayed on a monitor, or can be printed out on film.

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Individuals with the following items cannot be scanned:

• Pacemakers
• Metal filings
• Shrapnel, ferromagnetic clips or pins
• Recent tattoos (with black in them)
• Recent body piercings

If you have a pacemaker, you should not be imaged because the pacemaker may be damaged in the magnetic field of the scanner. If you have metal filings, shrapnel, or ferromagnetic clips or pins in your body, you probably will not be imaged because these objects could be twisted by the magnetic field and cause serious injuries. Most new surgical metal implants are made of a high quality stainless steel which is non-magnetic. You can be imaged with these. Dental fillings and bridgework are okay. Black Pigment in recent tattoos can contain a lot of iron that can heat up and potentially cause skin irritation or minor burns. Over time the iron leaches out of the tattoo and there is reduced risk of skin irritation. 

Other objects which may have been placed inside of your body, or certain medical conditions, may also be incompatible with your MRI exam. The process of identifying these contraindicators, as they are called, is called screening. MRI personnel will ask you many questions to determine if you can safely be imaged. You will also be asked your weight.

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Because an MRI produces no ionizing radiation, there are no known side effects associated with even the most prolonged exposure to the magnetic fields generated by the scanner (besides the special considerations listed in the previous question).

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An MRI is a primarily non-invasive imaging technique that requires the patient to lie in the magnet for a certain duration of time (and depending on the sequence and area of study). The patient will be asked to perform certain actions such as lying absolutely still or holding their breath. This is done to ensure the quality and accuracy of the image. Due to the design features, the magnet is very loud at times. Headphones or earplugs will be provided to counteract the noise. CDs may also be played during testing. 

RF coils are used to increase the quality of the image. Sometimes the coils may heat up during a scan (like a heating blanket) but that is completely normal and should be expected. A microphone is installed in the magnet so that you and the technologist can communicate, so if you feel any unusual sensations or discomfort please let the technologists know right away.

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If you are claustrophobic or think that you are claustrophobic, please contact the Nurse or the Physician Assistant for assistance prior to your arrival at the Center. If you require sedation, it will be necessary for someone to accompany you that can drive you home after the exam.

Some individuals do not realize that they are claustrophobic until they get into the magnet. Before your scheduled appointment, please consider the following questions:

1. Do you feel uncomfortable in a small enclosed space?
2. Have you ever felt uncomfortable, or had any anxiety in a crowded elevator?

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In certain circumstances it is felt that a MRI contrast agent administered intravenously would provide additional necessary information. In the following circumstances, an injection is required:

• If you are severely claustrophobic, intravenous sedation may be required.
• If you are scheduled for an evaluation of your urethra or prostate, you may receive an intramuscular injection to reduce bowel motion/spasms.
  

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IV Sedations:  Incidents of Occurrence less than 1%

• Respiratory Depression
• Involuntary Muscle Movement
• Hyperactivity
• Agitation
• Nausea
• Retrograde Amnesia
• Blurred Vision

Oral Sedation:  Ativan, Valium, Xanax

• Dry Mouth
• Drowsiness

MR Contrast

• Nausea
• Rare Allergic Reaction
• Rare Anaphylactic Reaction
  

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