Magnetic resonance imaging (MRI) uses a magnetic field and radio waves to create images of the body’s organs and tissues. This combination produces detailed images and keeps patients from being exposed to ionizing radiation.
What Is MRI Imaging?
MRI images are created through large magnets, a computer and radio waves. The involved scanner is shaped like a tube and has a table that passes through the middle. Before the procedure starts, the patient will lie down on the table, which then slides into the tube.
As the procedure begins, one of the magnets causes the body’s water molecules to move in one direction. The second magnet will be quickly turned on and off repeatedly, causing the body’s hydrogen atoms to vary in alignment.
At the same time, electricity passes through coils which vibrate and generate a magnetic field. When this occurs, the patient will hear a knocking sound in the scanner. The computer records the changes in the body to create detailed, cross-sectional images.
While patients are not exposed to ionizing radiation during an MRI, this procedure has a few risks. Contrast dye may be used for an even greater level of detail, potentially causing an allergic reaction in certain individuals. Patients are also known to experience claustrophobia within the tube and may need to first take an anti-anxiety drug.
Who Should Have an MRI?
MRIs are requested for diagnostic purposes or to monitor the progress of a treatment plan. Imaging can be performed on any portion of the body and is ideal for observing changes or abnormalities in soft tissue and the nervous system.
An MRI may be requested to:
- Assess the brain and spinal cord for damage
- Identify tumors, cysts and other growths within the body
- Examine the joints, including for the back and knee
- Observe the cardiovascular system, including the heart, blood vessels and changes after a stroke
- Examine the abdominal area for sources of pelvic pain, infertility and endometriosis
- Supplement mammography to screen for breast cancer
- Diagnose and monitor multiple sclerosis (MS)
- Obtain detailed images of the eyes and ears
- Help diagnose cancer
- Determine the source of nerve pain
- Diagnose a bone infection
Due to the mechanisms involved, MRIs are not recommended for certain patients, including:
- Pregnant women during the first trimester
- Patients with kidney disease, who may negatively react to the contrast dye
- Patients with a metal object inside their body, including clips for brain aneurysms, pacemakers, cardiac defibrillators, cochlear implants and certain blood vessel coils
Preparation for an MRI
Minimal to no preparation is required before an MRI. Scans can last anywhere from 20 to 60 minutes, based on the number of images needed and the area being observed.
Due to the magnetic field created, patients are required to remove jewelry, accessories, hearing aids and other metal objects that could disrupt image quality. Also inform your doctor if enclosed spaces make you anxious, as you may be prescribed medication to relax.
Before the procedure begins, you may be given an IV of contrast dye. You may be provided with blankets or cushions for a more comfortable experience. Children may also be given headphones for this purpose. The radiologist will talk to you from another room throughout the procedure over an intercom.
Movements can disturb image quality so once the scan begins, you will be asked to stay still or hold your breath at certain points. The scanner generates loud noises but these are normal. Should you feel uncomfortable, inform the technologist over the intercom.
Following the scan, a radiologist will examine the images, determining if the quality and number are sufficient. You may be asked to undergo additional imaging at this time. If not, patients may return to their everyday activities following the MRI.
The radiologist will send your results to your doctor, who will contact you to discuss the findings and determine if any follow-up procedures are needed.
Has your doctor recommended an MRI? Contact Midstate Radiology Associates to make an appointment today.
