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MRI

Magnetic resonance imaging (MRI)

Magnetic resonance imaging (MRI) is a technique that uses a magnetic field and radio waves to create detailed images of the organs and tissues within your body.

Most MRI machines are large, tube-shaped magnets. When you lie inside an MRI machine, the magnetic field temporarily realigns hydrogen atoms in your body. Radio waves cause these aligned atoms to produce very faint signals, which are used to create cross-sectional MRI images — like slices in a loaf of bread.

The MRI machine can also be used to produce 3-D images that may be viewed from many different angles.

Why it’s done

MRI is a noninvasive way for your doctor to examine your organs, tissues and skeletal system. It produces high-resolution images that help diagnose a variety of problems.

MRI of the brain and spinal cord

MRI is the most frequently used imaging test of the brain and spinal cord. It’s often performed to help diagnose:

  • Aneurysms
  • Disorders of the eye and inner ear
  • Multiple sclerosis
  • Spinal cord injuries
  • Stroke
  • Tumors
MRI of other internal organs

An MRI may be used to check for tumors or other abnormalities of many organs in the body, including the:

  • Liver
  • Kidneys
  • Spleen
  • Pancreas
  • Uterus
  • Ovaries
  • Prostate
  • Testicles
MRI of bones and joints

MRI may be used to help evaluate:

  • Joint disorders, such as arthritis
  • Joint abnormalities caused by traumatic or repetitive injuries
  • Disk abnormalities in the spine
  • Bone infections
  • Tumors of the bones and soft tissues

Patient Safety Tips Prior to the Procedure

The presence of metal in your body may be a safety hazard or affect a portion of the MRI image. Before receiving an MRI, tell the technologist if you have any metal or electronic devices in your body, such as:

  • Pacemaker
  • Pregnancy
  • Claustrophobia
  • History of kidney problems
  • Skin tattoos
  • Neurostimulators (TENS-unit)
  • Implanted drug infusion device (i.e., insulin pump)
  • Exposure of metal fragments to your eye
  • Artificial heart valves
  • Aneurysm clips
  • Cochlear implants
  • Metallic implants and prosthesis
  • Vascular stent or stent graft
  • History as a metal worker
  • Shrapnel or bullet wounds
  • Dorsal column stimulators
  • Allergy to iodine, or gadolinium
  • History of diabetes
  • Other conditions you believe to be relevant
Before you schedule an MRI, tell your doctor if you think you’re pregnant. The effects of magnetic fields on fetuses aren’t well understood. Your doctor may recommend choosing an alternative exam or postponing the MRI.

It’s also important to discuss any kidney or liver problems with your doctor and the technologist, because problems with these organs may limit the use of injected contrast agents during your scan.

Please leave your valuables at home, including jewelry, to prevent it from being lost or stolen, for they have to be removed prior to entering the scan room.

If you don’t want to change into hospital attire, please wear cotton clothing without any metal zippers, hooks, or buttons. The technologist will review what you are wearing and will determine if you may need to change into a gown.

Please let us know if you need interpreting services, this can be arranged for you.

Please bring a list of your current medications.

If you have claustrophobia your doctor may prescribe an oral medication for you to take with you for your MRI appointment.
During the test
The MRI machine looks like a tube that has both ends open. Our open MRI machine also has the sides open. 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.

The MRI machine creates a strong magnetic field around you, and radio waves are directed at your body. The procedure is painless. You don’t feel the magnetic field or radio waves, and there are no moving parts around you.

During the MRI scan, the internal part of the magnet produces repetitive tapping, thumping and other noises. Earplugs or music may be provided to help block the noise. If you are worried about feeling claustrophobic inside the MRI machine, talk to your doctor beforehand. You may receive a sedative before the scan.

In some cases, a contrast material, typically gadolinium, may be injected through an intravenous (IV) line into a vein in your hand or arm. The contrast material enhances the appearance of certain details.

An MRI can last up to an hour or more. You must hold very still because movement can blur the resulting images.

What can I expect after my MRI scan?

If a dye injection is used, the IV is removed from the arm before you go home.

Allergic reaction from gadolinium dye is extremely rare. However, if you experience symptoms such as rash, hives, or shortness of breath, you should notify the technologist immediately if you are still at the imaging facility, or call your doctor or go to the nearest hospital if you have already left the imaging facility.

In the event that your doctor has prescribed you sedation, someone must drive you home.
Results

MRI images are stored as electronic data files and usually reviewed on a computer screen. A radiologist interprets these images and sends a report to your doctor within a 48 hour period.

Claustrophobia and Minimizing Your Fears
If you are scared about your MRI, keep in mind that people talk about MRI and claustrophobia (fear of being in a closed space) based on what they have heard or experienced in the past. Not all of this is true today, and certainly not at MRI Imaging Center of Fresno, Inc. Older MRI machines had narrower tunnels than the modern MRI equipment. The older machines were often relatively dark, and the scanner’s ceiling was very close to the patient’s face and head.

MRI Imaging Center of Fresno, Inc. has taken the following measures to help those who expect to feel claustrophobic during MRI:
  • We have an Open MRI Scanner located at our Shaw Ave location that you may request.
  • Our high field scanner is fully lit, ventilated, open at both ends and is like being in a tanning bed.
  • For some MRI exams, depending on the body part being imaged, we may not need to have your head inside the scanner at all. This dramatically lowers the expectation or experience of claustrophobia. For example, exams of the knee, foot or leg do not require patients to enter the MRI scanner tube completely—only the leg is in the tube.
  • At MRI Imaging Center of Fresno, Inc. we treat you like the individual you are. We try to find the most comfortable and easiest method for you to successfully complete your MRI. Our well-trained technologists work very closely with you to help lower anxieties, and we will tell you how long to expect your exam. If you are concerned about how you will tolerate your MRI exam, we urge you to ask your doctor to develop a plan to help you. If you are having a MRI appointment, your doctor may prescribe an oral medication for you to take to minimize your anxiety.
  • During your exam, our technologist will see you and be in contact with you at all times. Speakers inside the scanner will enable the technologist to communicate with you and hear what you say. You also will have a call button (in the form of a squeeze ball) so that you can let the technologist know if you have any problems relaxing during the procedure.
  • You can be given earplugs or a headset with music to help block out noise from the scanner.
  • If you are getting an MRI of the Head, the head coil that is used resembles a Basebal Catcher’s mask. You can see out and it has cut out openings on all sides.
  • You may bring a friend or family member to the appointment. They can sit with you as you have the exam as long as they do not have a pacemaker, history of metal in eyes, brain aneurysm clips, or any electronic mechanical pumps implanted in their body. Do not bring a friend that is very negative or claustrophobic themselves. They may talk to you between sequences and/or hold your foot or hand if needed.
  • You are welcome to see the machine in advance and talk with the technologist a few days prior to the exam to see our high field magnet.