Magnetic Resonance Imaging (MRI)
Johnson County Imaging has a 1.5T MRI. Magnetic Resonance Imaging is a safe diagnostic imaging technique which uses a magnetic field and radio waves to produce pictures of your body. X-rays are not used.
The MRI scanner sends out radio signals to the hydrogen atoms found in the water molecules in your body. The hydrogen atoms then send back radio signals which are recorded by the MRI scanner. A computer compiles this information and produces cross-sectional images of your body, very much like slices from a loaf of bread. The procedure provides excellent images of soft tissue structures like the brain, spinal cord, muscle and certain internal organs as well as joint anatomy.
You will be asked if you have any metal objects in your body, since the metal may interfere with the magnetic field. MRI cannot be performed on people with:
- Cardiac pacemaker or defibrillators
- Brain aneurysm clips
- Metal fragments in the eye (plain film x-rays will be done of the orbits, if there is a prior history of metallic foreign body.)
If you are having a scan of the head, we recommend that you do not wear heavy eye makeup as the metal particles in the makeup may interfere with your exam. You may follow your normal diet and take any medications in your usual fashion.
During the Exam
When you arrive, you may need to change into a gown, and will be asked to remove all metal objects before going into the scanning room. You may wish to leave your jewelry and valuables at home, or we have secured lockers where you can store these items.
The technologist will help position you on a padded table in front of the magnet. Depending on the type of exam you are having, you will then enter the scanner head first or feet first. The technologist will begin by moving the table into the magnet. During the exam, the technologist will be inside the control room watching you at all times. An intercom system allows you to talk freely with technologist.
As the exam starts, you may hear a variety of thumping noises, similar to light hammering. Some people find this noise relaxing, but we also have earplugs for your comfort. While the scanner is working, you may feel a slight vibration. This procedure takes usually 45 – 60 minutes depending on the exam. Some exams may require an injection of a contrast material, dependent on the exam preformed.