MRI (Magnetic Resonance Imaging)
What is magnetic resonance imaging (MRI)?
MRI is a diagnostic procedure that uses a combination of a large magnet, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. An MRI is often used:
- to examine the heart, brain, liver, pancreas, extremities, spine, male and female reproductive organs, and other soft tissues.
- to assess blood flow.
- to detect tumors and diagnose many forms of cancer.
- to evaluate infections.
- to assess injuries to bones and joints.
Houston Methodist Willowbrook Hospital has a 1.5 Tesla MRI, the latest 16 channel MRI scanner that provides a full range of applications and services. This imager provides state-of-the-art diagnosis of stroke, breast disease, and vascular imaging, and function images of the brain and spinal cord. Patients undergoing MR examinations at Houston Methodist Willowbrook Hospital enjoy the benefits of a very experienced and dedicated technical and support staff, along with sub-specialized readings by fellowship-trained radiologists providing fast report turnaround times.
A breast MR is a non–invasive procdure that uses magnets and radio frequencies to produce a picture of the inside of the body. ths test is not painful and there is no harmful radiation involved. It is usually done for breast cancer staging or for evaluating implants. A breast MR is extremely helpful in evaluating mammogram abnormalities and identifying early breast cancer, especially in women at high risk. High–risk women include those who have had breast cancer or have a mother or sister who has been diagnosed with breast cancer. Breast MR provides unsurpassed clarity in breast imaging and is used most commonly in high–risk women when the findings of a mammogram or ultrasound are inconclusive because of dense breast tissue, which is often found in younger woman, or there is a suspected abnormality that can be felt but are not visible and requires further evaluation.
How does an MRI scan work?
MRI can be performed on an outpatient basis, or as part of inpatient care. The MRI machine is a large, cylindrical (tube-shaped) machine that creates a strong magnetic field around the patient. This magnet field, along with a radio frequency, alters the alignment of the hydrogen atoms within the body. Computers are then used to form 2-dimensional images of a body structure or organ, based on the activity of the hydrogen atoms. Crosssectional views can be obtained to reveal further details. Unlike CT or X-ray studies, MRI does not employ radiation.
How is an MRI performed
Although each hospital may have specific protocols in place, generally, an MRI procedure follows this process:
- Because of the strong magnetic field, the patient must fill out a safety questionnaire and remove all jewelry and metal objects such as hairpins or barrettes, hearing aids, eyeglasses, and dental pieces.
- If a contrast medium is to be given intravenously (IV), an IV line will be started in the patient's hand or arm. The IV line will be used to inject contrast at the appropriate time.
- The patient lies on a table that slides into the scanner.
- The MRI staff will have the patient in constant sight. Audio speakers inside the scanner will enable the staff to communicate with and hear the patient. The patient will have a call bell so that helshe can let the staff know if they experience any problem during the MRI examination.
- During the scanning process, a loud knocking noise occurs. The patient will be given earplugs to wear to help block out the noises from the MRI scanner.
- It is important that the patient remain very still during the examination.
- For abdominal, cardiac, andlor chest scans, the patient will be instructed to hold hislher breath, for about 10-25 seconds. The patient will then be told when he/she can breathe. The patient should not have to breath-hold for longer than 30 seconds to avoid discomfort.
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Are there special preparation requirements for the exam?
The MRI safety form must be completed prior to exam.
What should I expect during the procedure?
- Before you begin the MRI you may be asked to change into a clinic gown before being escorted to the MRI room. A MRI technologist will assist you on to the exam table and position you for the procedure. During the procedure, you will need to lie as still as possible; any type of movement can cause the MRI images to blur thus requiring the MRI technologist to repeat part of the procedure.
- While the MRI is in session you will hear knocking sounds during the procedure. Earplugs, headphones, or music can be provided for your comfort. While the MRI is in session the MRI technologist will be in constant communication with you during the procedure using a two-way microphone system so if you are feeling uncomfortable in any way, please inform your MRI technologist.
- Blankets and/or pillows will be provided upon request for your comfort. The temperature in the MRI exam room is typically cool in order to ensure that the computer system operates properly.
- Some patients may be required to take an intravenous injection of a contrast material to enhance the visibility of certain tissues or blood vessels.
- Houston Methodist Willowbrook Hospital Imaging Centers goal is to provide each patient with a pleasant and comfortable MRI procedure. If you feel uncomfortable in any way, please inform your MRI technologist.
How long will the exam take?
The exam will take about 30 to 60 min.
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Reminders before the examination
Nothing to eat or drink 4 hours prior to a MRI of Abdomen.
Tell the technologist:
- if you are claustrophobic and think that you will be unable to lie still while inside the scanning machine.
- if you have a pacemaker inserted, or have had heart valves replaced.
- if you have metal plates, pins, metal implants, surgical staples, or aneurysm clips.
- if you have permanent eye liner.
- if you are pregnant.
- if you ever had a bullet wound.
- if you have ever worked with metal (i.e., a metal grinder).
350 pound weight limit.
For more information about Willowbrook Imaging & Diagnostic Services at the Houston Methodist Willowbrook Hospital, please call 281-737-1234.
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