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8/14/2019 What is MRI Magnetic Resonance Imaging (MRI) is a Noninvasive
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What is MRI
Magnetic resonance imaging (MRI) is a noninvasive medical test that helps physicians
diagnose and treat medical conditions.
MR imaging uses a powerful magnetic field, radio frequency pulses and a computer toproduce detailed pictures of organs, soft tissues, bone and virtually all other internal body
structures. The images can then be examined on a computer monitor, printed or copied to
CD. MRI does not use ionizing radiation (x-rays).
Detailed MR images allow physicians to better evaluate various parts of the body andcertain diseases that may not be assessed adequately with other imaging methods such as
x-ray, ultrasound orcomputed tomography(also called CT or CAT scanning).
What are some common uses of the procedure?
MR imaging of the body is performed to evaluate:
organs of the chest and abdomenincluding the heart,liver,biliary tract,kidney,
spleen, andpancreas and adrenal glands.
pelvic organs including the reproductive organs in the male (prostate andtesticles) and the female (uterus, cervix and ovaries).
blood vessels (MR Angiography).
breasts.
Physicians use the MR examination to help diagnose or monitor treatment for conditionssuch as:
tumors of the chest, abdomen or pelvis.
certain types of heart problems.
blockages or enlargements of blood vessels, including the aorta, renal arteries, and
arteries in the legs. diseases of the liver, such as cirrhosis, and that of other abdominal organs,
including the bile ducts, gallbladder, and pancreatic ducts. cysts and solid tumors in the kidneys and other parts of the urinary tract.
tumors and other abnormalities of the reproductive organs (e.g., uterus, ovaries,
testicles, prostate).
causes of pelvic pain in women, such as fibroids, endometriosis and adenomyosis.
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Overall, the differentiation of abnormal (diseased) tissue from normal tissues is often
better with MRI than with other imaging modalities such as x-ray, CT and ultrasound.
How is the procedure performed?
MRI examinations may be performed on outpatients or inpatients.
You will be positioned on the moveable examination table. Straps and bolsters may beused to help you stay still and maintain the correct position during imaging.
Small devices that contain coils capable of sending and receiving radio waves may beplaced around or adjacent to the area of the body being studied.
If a contrast material will be used in the MRI exam, a nurse ortechnologistwill insert anintravenous (IV) line into a vein in your hand or arm. A saline solution may be used. The
solution will drip through the IV to prevent blockage of the IV line until the contrast
material is injected.
You will be moved into the magnet of the MRI unit and the radiologist and technologist
will leave the room while the MRI examination is performed.
If a contrast material is used during the examination, it will be injected into theintravenous line (IV) after an initial series of scans. Additional series of images will betaken during or following the injection.
When the examination is completed, you may be asked to wait until the technologist or
radiologist checks the images in case additional images are needed.
Your intravenous line will be removed.
MRI exams generally include multiple runs (sequences), some of which may last severalminutes.
Depending on the type of exam and the equipment used, the entire exam is usually
completed in 15 to 45 minutes.
MR spectroscopy, which provides additional information on the chemicals present in the
body's cells, may also be performed during the MRI exam and may add approximately 15minutes to the exam time.
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What will I experience during and after the procedure?
Most MRI exams are painless.
Some patients, however, find it uncomfortable to remain still during MR imaging. Others
experience a sense of being closed-in (claustrophobia). Therefore, sedation can bearranged for those patients who anticipate anxiety, but fewer than one in 20 require it.
It is normal for the area of your body being imaged to feel slightly warm, but if it bothers
you, notify the radiologist or technologist. It is important that you remain perfectly still
while the images are being recorded, which is typically only a few seconds to a fewminutes at a time. For some types of exams, you may be asked to hold your breath. You
will know when images are being recorded because you will hear tapping or thumping
sounds when the coils that generate the radiofrequency pulses are activated. You will beable to relax between imaging sequences, but will be asked to maintain your position as
much as possible.
You will usually be alone in the exam room during the MRI procedure. However, the
technologist will be able to see, hear and speak with you at all times using a two-wayintercom. Many MRI centers allow a friend or parent to stay in the room as long as they
are also screened for safety in the magnetic environment.
You may be offered or you may request earplugs to reduce the noise of the MRI scanner,
which produces loud thumping and humming noises during imaging. MRI scanners areair-conditioned and well-lit. Some scanners have music to help you pass the time.
When the contrast material is injected, it is normal to feel coolness and a flushing
sensation for a minute or two. The intravenous needle may cause you some discomfortwhen it is inserted and once it is removed, you may experience some bruising. There isalso a very small chance of irritation of your skin at the site of the IV tube insertion.
If you have not been sedated, no recovery period is necessary. You may resume your
usual activities and normal diet immediately after the exam. A few patients experience
side effects from the contrast material, including nausea and local pain. Very rarely,patients are allergic to the contrast material and experience hives, itchy eyes or other
reactions. If you experience allergic symptoms, a radiologist or other physician will be
available for immediate assistance.
Who interprets the results and how do I get them?
A radiologist, a physician specifically trained to supervise and interpret radiology
examinations, will analyze the images and send a signed report to your primary care or
referring physician, who will share the results with you.
What are the benefits vs. risks?
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Benefits
MRI is a noninvasive imaging technique that does not involve exposure to
ionizing radiation.
MR images of the soft-tissue structures of the bodysuch as the heart, liver and
many other organs is more likely in some instances to identify and characterizeabnormalities and focal lesions than other imaging methods. This detail makes
MRI an invaluable tool in early diagnosis and evaluation of many focal lesionsand tumors.
MRI has proven valuable in diagnosing a broad range of conditions, including
cancer, heart andvascular disease, and muscular and bone abnormalities.
MRI enables the discovery of abnormalities that might be obscured by bone with
other imaging methods.
MRI allows physicians to assess the biliary system noninvasively and withoutcontrast injection.
The contrast material used in MRI exams is less likely to produce an allergic
reaction than the iodine-based materials used for conventional x-rays and CTscanning. MRI provides a fast, noninvasive alternative to x-ray angiography for diagnosing
problems of the heart and blood vessels.
Risks
The MRI examination poses almost no risk to the average patient whenappropriate safety guidelines are followed.
If sedation is used there are risks of excessive sedation. The technologist or nurse
monitors your vital signs to minimize this risk.
Although the strong magnetic field is not harmful in itself, implanted medicaldevices that contain metal may malfunction or cause problems during an MRI
exam.
There is a very slight risk of an allergic reaction if contrast material is injected.Such reactions usually are mild and easily controlled by medication. If you
experience allergic symptoms, a radiologist or other physician will be available
for immediate assistance.
Nephrogenic systemic fibrosis is currently a recognized, but rare, complication of
MRI believed to be caused by the injection of high doses of MRI contrast material
in patients with very poor kidney function.
What are the limitations of MRI of the Body?
High-quality images are assured only if you are able to remain perfectly still or hold your
breath, if requested to do so, while the images are being recorded. If you are anxious,
confused or in severe pain, you may find it difficult to lie still during imaging.
A person who is very large may not fit into the opening of a conventional MRI machine.
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The presence of an implant or other metallic object sometimes makes it difficult to obtain
clear images and patient movement can have the same effect.
Breathing may causeartifacts, or image distortions, during MRIs of the chest, abdomenand pelvis. Bowel motion is another source of motion artifacts in abdomen and pelvic
MRI studies. This is less of a problem with state-of-the art scanners and techniques.
Although there is no reason to believe that magnetic resonance imaging harms the fetus,
pregnant women usually are advised not to have an MRI exam unless medicallynecessary.
MRI may not always distinguish between cancer tissue andedema fluid.
MRI typically costs more and may take more time to perform than other imaging
modalities.
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Sagittal MR image of the knee
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Breast MRI.
Breast MRI is a non-invasive procedure used to further look at breast tissue. There aretwo types of breast MRI exams: with contrast or without contrast. Contrast (a special dye
that helps highlight breast tissue) is used to evaluate for suspected or known breast cancer
or for a screening exam in certain high-risk patients together with a screeningmammogram. Breast MRI does not replace mammography and ultrasound, but rather is
an adjunct exam. Non-contrast exams are for evaluating breast implants.
Breast coil
Patient on a scanner bed
Patient in the scanner bore during the exam
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Exam preparation
A staff representative will call you prior to your appointment to provide specific
instructions, and review health and insurance information. Please bring previous studies to the appointment, including ultrasound,
mammography and MRI exams.
Contrast Breast MRI exams are ideally performed between days 7-12 of yourmenstrual cycle.
If sedation is requested, you should arrange for someone to drive you home.
Breast MRI exams take 60 to 90 minutes to perform.
During the exam what to expect
If your exam requires contrast, you will be given an I.V. in your arm or hand prior
to your scan.
As with all MRI exams, you are asked to remove any metal from your body andrequired to change into a gown.
During the exam, you will lay on your stomach with both breasts naturally
positioned in a cushioned recess containing the MRI scanners signal receiver
(also known as a breast coil). Your head will be positioned on a headrest that isequipped with mirrors so you can see out of the scanner during the exam. Your
arms will be positioned above your head.
The entire bed will advance forward into the opening of the MRI scanner.
You will need to lie still while the computer acquires the images.
Next, contrast, called Gadolinium, will be injected through the I.V. during the
scan. Gadolinium is an FDA-approved, non-radioactive contrast agent that helpsthe physician better view potential lesions/tumors.
Additional images will be taken.
What happens after the exam
Ask a member of our staff for more specific information on when and how you will
receive your results. However, in general you can expect:
A radiologist who specializes in breast imaging will review your images.
The radiologist prepares a diagnostic report and images to share with your doctor.
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Your doctor will consider this information in context of your overall care, and talk
with you about the results.
The IV contrast is rapidly cleared from the body by the kidneys after the exam.However, breastfeeding women should discard milk for 48 hours after the exam.
MR Spectroscopy.
Magnetic Resonance Spectroscopy (MRS) is used as an adjunct to our routine MRIbrainexamination. MRI is used to create multi-dimensional pictures of your brain in order to
look for differences in structure. Information gathered during the MRI portion of the
exam is analyzed using Spectroscopy, which looks at the chemical make-up of differentbrain regions.
Exam preparation
A CDI representative will call you prior to your appointment to provide you
specific instructions, and review health and insurance information. Bring prior x-rays or scans with you to your exam, if instructed.
Because of the magnetic field, you will be asked to wear metal-free clothing. Youalso will be asked to remove any metallic objects, such as jewelry, watches, and
hair clips.
Inform your technologist of prior surgeries or metal implants, such as pacemakers
or aneurysm clips. Notify a member of CDIs staff if your are nursing or if there is a chance you
could be pregnant.
If it is decided when scheduling your appointment that sedation is necessary, youwill need to arrange a driver.
Please arrive 15 minutes early to verify your registration.
During the exam what to expect
You lie on a cushioned table and an imaging device called a coil is placed
around your head.
Once comfortably positioned, the table moves into the magnet opening.
As images are acquired, you hear knocking sounds for several minutes at atime.
It is important to lie as still as possible during this part of the exam.
Gathering information for the Spectroscopy portion of the exam will require anadditional 10-15 minutes in the scanner.
Information gathered will be post-processed on a computer workstation and
analyzed using Spectroscopy, which looks at the chemical make-up of differentbrain regions.
After the exam what to expect
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A radiologist who specializes in a specific area of the body will review your
images (i.e., a neuroradiologist will review images of your brain).
The radiologist prepares a detailed diagnostic report to share with your doctor.
Your doctor will consider this information in context of your overall care, and talk
with you about results.
Diffusion MRI.
Diffusion imaging is used as an adjunct to our routine MRIbrain examination. Diffusion
measures the movement of water in the brain, detecting areas where the normal flow ofwater is disrupted. A disrupted flow of water indicates where there could be an
underlying abnormality.
Exam preparation
A CDI representative will call you prior to your appointment to provide you
specific instructions, and review health and insurance information.
Bring prior x-rays or scans with you to your exam, if instructed.
Because of the magnetic field, you will be asked to wear metal-free clothing. You
also will be asked to remove any metallic objects, such as jewelry, watches, and
hair clips.
Inform your technologist of prior surgeries or metal implants, such as pacemakers
or aneurysm clips.
Notify a member of CDIs staff if your are nursing or if there is a chance you
could be pregnant. If it is decided when scheduling your appointment that sedation is necessary, you
will need to arrange a driver.
Please arrive 15 minutes early to verify your registration.
During the exam what to expect
You lie on a cushioned table and an imaging device called a coil is placed
around your head.
Once comfortably positioned, the table moves into the magnet opening. As images are acquired, you hearknocking sounds for several minutes at a
time.
It is important to lie as still as possible during this part of the exam. Your routine MR exam will include an additional diffusion-weighted sequence,
which will lengthen the scan by 1 minute.
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After the exam what to expect
A radiologist who specializes in a specific area of the body will review your
images (i.e., a neuroradiologist will review images of your brain).
The radiologist prepares a detailed diagnostic report to share with your doctor.
Your doctor will consider this information in context of your overall care, and
will talk with you about the results.
MR Angiography.
Magnetic Resonance Angiography (MRA) is an MRI study of blood vessels. MRA
utilizes advanced MRI technology to detect, diagnose, and aid in the treatment ofvascular disorders or abnormalities in the head, neck, arms, legs and abdomen. MRA
highlights the vessels through the use of gadolinium-based contrast (dye) material. This
procedure is best performed on a high-field MRI scanner.
Exam preparation
A CDI representative will call you prior to your appointment to provide specific
instructions, and review health and insurance information
Because of the magnetic field, you will be asked to wear metal-free clothing, or to
change into a gown. You also will be asked to remove any metallic objects, such
as jewelry, watches, and hair clips.
Inform your technologist of prior surgeries or metal implants, such as pacemakers
or aneurysm clips.
Notify a member of CDIs staff if you are nursing or if there is a chance you
could be pregnant Bring prior x-rays or scans with you to your exam, if instructed.
Please arrive 15 minutes early to verify your registration.
During the exam what to expect
You will lie on a cushioned table and an imaging device called a coil will be
placed around the area of the body to be scanned.
Once comfortably positioned, the table will move into the magnet opening.
As images are acquired, you hearknocking sounds for several minutes at a
time. It is important to lie as still as possible during this part of the exam to ensureclear images.
If contrast material needs to be used, you will receive an I.V. in the hand or arm
before you are moved inside the scanner.
Once the contrast, called gadolinium, is injected, you may feel a warm, flushed
sensation, and experience a metallic taste in your mouth that lasts for about twominutes.
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Additional pictures will be taken once the contrast is injected. Depending on the
type of exam, you could be in the scanner anywhere from 10 minutes to one hour.
After the exam what to expect
A radiologist who specializes in a specific area of the body will review your
images (i.e., a neuroradiologist will review images of your brain).
The radiologist prepares a diagnostic report to share with your doctor.
Your doctor will consider this information in context of your overall care, and
will talk with you about the results.
MRI PREPARATION
Preparation
Preparation for your MRI will depend on the type of exam; a center representativewill call you prior to your appointment to provide specific instructions, and
review health and insurance information.
Please bring your previous imaging study results (MRI, CT, x-rays) such as
reports, films or CD-Roms, if available.
Because of the magnetic field, you will be asked to wear metal-free clothing, or tochange into a gown. You also will be asked to remove any metallic objects, such
as jewelry, watches, and hair clips.
Inform your technologist of prior surgeries or metal implants, such as pacemakers
or aneurysm clips. Notify a member of our staff if your are nursing or if there is a chance you could
be pregnant. Please arrive 15 minutes early to verify your registration. You will need to review
and sign the MRI Checklist before your scan.
During the exam what to expect
You will lie on a cushioned table and often an imaging device called a coil willbe placed around the area of the body to be scanned.
Once you are comfortably positioned, the table will move into the magnet
opening.
As images are acquired, you will hearknocking or buzzing sounds for a fewminutes at a time. It is important to lie as still as possible during this part of the
exam to help us capture clear images.
If necessary, physician-administered medication is available to help you relax.
In some cases, you will need contrast material to further aid in detection or
diagnosis of potential abnormalities. In this instance, an I.V. will be placed in
your hand or arm. Once the contrast is injected, you will feel a warm, flushed
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sensation, and may experience a metallic taste in your mouth that lasts for about
two minutes.
After the exam what to expect
A radiologist who specializes in a specific area of the body will review your
images.
The radiologist prepares a detailed diagnostic report to share with your doctor.
Your doctor will consider this information in context of your overall care, and talk
with you about the results.
Advanced Technology.
Every MRI scanner has what is called field strength. Field strength is the power of the
scanners magnet. With higher field strengths, your scan pictures are clearer and showsmaller details of your body. We offer a range of MR field strengths, including 1.5T and3T high-field, short scanners, as well as 0.7T Open scanners, .6T Open Upright and .
2-.35T Open scanners.
Our MRI scanner technology varies by market; contact the center nearest you and ask for
more information.
Because of its superior quality, high-field MRI should be your first choice whenever
possible.
Open scanners can be a good alternative for severely claustrophobic or large patients,
however more detailed can be captured through a scanner with a higher field strength.
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Brain image obtained on a high-field (3T), short MRI scanner. This image clearly
demonstrates that a high-field scanner creates more detailed images than a low-fieldscanner (shown below). The clearer the image, the easier it will be for your doctor to
make an accurate and decisive diagnosis.
Brain image obtained on a low-field (.2T), open MRI scanner.