What does the equipment look like?

 

Most MRI machines consist of a large cylinder-shaped tube that is open on both ends and  surrounded by a circular magnet. You lie down on a movable table that slides into the opening of the tube. A technologist monitors you from another room. You can talk with the person by microphone.

 

What can I expect before my MRI exam?

There is little preparation for an MRI exam. Take your daily medications as you normally would unless instructed otherwise. There are few dietary restrictions for an MRI. For those exams, you will be notified of the requirements.

  • Please arrive 30 minutes prior to your exam and check in with the receptionist. You will need to complete the MRI screening form. 
  • To eliminate possible MR safety issues, you will be asked to change into a hospital gown. A locker will be supplied to secure your belongings.

A technologist will verify your identification and the requested exam. Your screening form will be reviewed by the technologist in consultation with the radiologist if indicated. If MRI contrast is indicated for the exam, an IV catheter will be inserted in your arm by a nurse or technologist.

How does the procedure work?

MRI does not utilize ionizing radiation. Instead, radiofrequency pulses re-align hydrogen atoms that naturally exist within the body. This does not cause any chemical changes in the tissues. As the hydrogen atoms return to their usual alignment, they emit different amounts of energy depending on the type of body tissue they are in. The MR scanner captures this energy and creates a picture of the tissues scanned based on this information.

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. The electric current does not come in contact with the patient.

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 radiologist.

 

What will I experience during and after the procedure?

  • The duration of the procedure will vary but the average is 45 minutes to one hour per body part. 
  • You will be required to lie still during the actual MR scanning. Depending on the body part that is being examined, you may be instructed to hold your breath for up to 30 seconds.
  • The magnet is permanently open on both ends. It is well lit and there is a fan for patients comfort. There is also a two-way intercom system for communication between patient and technologist. The part of the body being scanned will be placed in the middle of the magnet.
  • During the actual imaging, you will hear a loud intermittent banging noise. You will be provided with earplugs or headphones to minimize the noise during the procedure. 
  • The technologist will also provide you with an alarm button to alert the technologist of any discomfort you may experience at any point during the MRI exam. 

Some MRI exams require an injection of intravenous MRI contrast. Inform the technologist if you experience any discomfort during the injection.

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