What is MRI?

MRI is one of the best diagnostic exams for imaging many types of soft-tissue including:


•    the brain, vessels of the brain, eyes, inner ear
•    the neck, shoulders, cervical spine and blood vessels of the neck
•    the heart, aorta and coronary arteries
•    the thoracic and lumbar spine
•    the upper abdomen, liver, kidney, spleen, pancreas and other abdominal vessels
•    the pelvis and hips, male and female reproductive system, and bladder
•    the musculoskeletal skeletal system including joints such as the shoulder, knee, wrist, ankles and feet


MRI and MR angiography are finding a greater role in the detection, diagnosis and treatment of heart disease, heart attack, acute stroke and vascular disease which can lead to stroke. Additionally, MR imaging is a vital part of diagnosing and treating sports injuries, and MR is finding an increasing role in diagnostic mammography. MR is a powerful tool for finding and diagnosing many forms of cancer.

What is MRI?


MRI stands for Magnetic Resonance Imaging. This test provides a means of obtaining images of various parts of your body without the use of x-rays (ionizing radiation). MR uses magnetic energy and radio waves to create cross-sectional images or "slices" of the human body. A specialized antenna transmits radiofrequency energy (RF) into the body and then receives the RF signals back. These returning signals are converted into pictures by a computer attached to the scanner. Pictures of almost any part of your body can be obtained at almost any angle. The main component of most MR systems is a large tube shaped or cylindrical magnet. Most of the cylindrical magnets have a strength between 0.5 and 1.5 Tesla and most of the Open or C-shaped magnets have a magnetic strength between 0.01 and 0.35 Tesla. 


The Imaging Center of Las Cruces has both a 1.5 Tesla MR (system which has a magnetic field 30,000 times stronger than the pull of gravity on the earth's surface) and a .3 Tesla Open Magnet.


IS MRI safe?


MRI is safe in the majority of patients although certain patients may not be able to have an MRI. These include people who are extremely claustrophobic and those with implanted medical devices such as certain aneurysm clips in the brain, heart pacemakers, and cochlear (inner ear) implants. Also, those people with pieces of metal close to or in an important organ (such as the eye) may not be scanned. Please inform the technologist if you are pregnant or breast-feeding. There are a few additional safety considerations and some exceptions based on individual circumstances.

What will the MRI experience be like?


You will be asked to lie still on a table that will move your body into the center of the magnet. Prior to the table moving, you will be offered either earplugs to reduce the noise you hear or stereo headphones to listen to your favorite music. You will hear some "knocking" noises while the scanner is preparing for scanning and taking the pictures. You may also feel some vibration during the knocking noise and some slight movement of the table during the examination. Each total MR examination typically is comprised of a series of 2 to 6 sequences, with each sequence lasting between 2 and 15 minutes. An "MR sequence" is an acquisition of data that yields a specific image orientation and a specific type of image appearance or "contrast." Thus a typical exam can last for a total of ten minutes to an hour, depending on the type of exam being run and the MR system being used.


Some patients will be given an injection in a vein in their arm containing a substance that improves certain types of images. This substance, called gadolinium, is a very safe contrast agent and is unrelated to the iodine used for CT scans and kidney x-rays.


What are the uses and advantages of an MRI?


MRI scanners are good for looking at the non-bony party, or "soft tissues" of the body. In particular, the brain, spinal cord, and nerves are seen much more clearly with MRI than regular x-rays and CT scans. Also, MRI scans are commonly used to look at knees and shoulders following injury to assess the muscles, ligaments, and tendons. Additionally, a MR scanner uses no x-rays or other radiation and is non-invasive.

MR is one of the best diagnostic exams for imaging many types of soft-tissue including:
    the brain, vessels of the brain, eyes, inner ear
    the neck, shoulders, cervical spine and blood vessels of the neck
    the heart, aorta and coronary arteries
    the thoracic and lumbar spine
    the upper abdomen, liver, kidney, spleen, pancreas and other abdominal vessels
    the pelvis and hips, male and female reproductive system, and bladder
    the musculoskeletal skeletal system including joints such as the shoulder, knee, wrist, ankles and feet


MR imaging and MR angiography are finding a greater role in the detection, diagnosis and treatment of heart disease, heart attack, acute stroke and vascular disease which can lead to stroke. Additionally, MR imaging is a vital part of diagnosing and treating sports injuries, and MR is finding an increasing role in diagnostic mammography. MR is a powerful tool for finding and diagnosing many forms of cancer.


What Is MRI, and How Does It Work?


Magnetic resonance imaging (MRI) technology is unrivaled in its ability to produce high resolution images of soft tissue and structural anatomy. Conditions that may only be apparent from physical signs and symptoms may be clearly seen, providing better information to determine appropriate treatment. During a MRI examination the part of your body to be studied, will be positioned in the center of a magnetic field and scanned. In some cases, the radiologist will recommend an intravenous (IV) contrast injection to further enhance the results of the study.

MRI, which uses magnetic fields, radio waves and complex computer processing to produce sectional images of the body, has revolutionized the field of musculoskeletal and neurologic imaging. Images of the brain, spine and joints, not attainable with any other imaging modality are produced with no exposure to radiation. MRI can also depict the liver, gallbladder, pancreatic ducts and bile ducts (MRCP MR cholangiopancreatography). MRI can be used to examine arteries of the brain, neck, chest, abdomen and extremities.

Due to the strength of magnetic fields used in MRI and the configuration of the magnet, certain conditions may prevent MRI examination of some patients. Patients with a cardiac pacemaker or brain aneurysm clips cannot safely have a MRI exam. Without sedation, infants, small children, claustrophobic patients and / or those with severe pain or physical limitations may not be able to complete a MRI exam, which requires the patient to lie still. For safety reasons, all patients are carefully screened before being placed inside the magnet. In some circumstances short bore MRI, open MRI or CT may provide alternatives for examination.

When you are placed inside a large magnet field for your examination, the protons in your body's hydrogen atoms temporarily align themselves in a position to receive radio signals from the MRI unit. As the MRI sends these signals, your body responds with signals of its own. The computer captures these signals, analyzes them and translates them into an image of the body part being scanned. These digital images are sent to a computer workstation for review and are digitally archived (stored) for long term use.
 

What to Expect During an MRI Exam


MRI examinations are painless. ALL MRI exams involve strong magnetic fields. For your safety, each MRI appointment requires completion of a screening form to identify any condition you may have that could prevent a MRI examination

Before your scan, a MRI technologist will review your medical/allergy history and answer any questions you may have. He / she will keep you informed and support you throughout the study and be there to help you out of the scanner when the examination is complete.

Some MRI examinations require an intravenous (IV) contrast injection (during the exam) to enhance the results of your study. This injection, performed by a nurse or technologist, is placed in a vein in your hand or arm. Contrast reactions / allergies* to the contrast agent, Gadolinium, are rare.

You may be asked to change into a gown before your examination to avoid possible magnetic interference from buckles, snaps, zippers, earrings or silk screening.

Your MRI scan will take place in a specially designed room. You will be helped to lie down on a padded table. The table slides into a large cylindrical magnet (open at both ends). The body part to be studied is positioned in the center of the magnetic field.

Your MRI scan may require that a coil apparatus be placed around the part of your body that your physician is concerned about. This coil enhances visualization of the area of interest.

Motion can distort images, so you will be asked to lie still for periods of 5 to 15 minutes. Total examination times vary from 30 minutes to 1 hour or more depending, on the information needed.

While the machine is in operation, it is normal to hear intermittent humming and thumping sounds. An intercom system in the room will enable you to communicate with the technologist at anytime during your scan. All rooms are air-conditioned, and listening to music is optional.
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How to Prepare for Most MRI Exams - Adult and Child (Over 6 Years of Age)
Please call outpatient imaging locations or hospital departments if you think you have a condition that might prevent a MRI exam.

Contraindications
o    Pacemaker
o    Aneurysm clips, stents
o    Inner ear implants
o    Pregnant
o    Bone or neuro stimulators
o    Metal shavings and / or BB's in your eyes
o    Permanent eyeliner, piercings
o    Some physical limitations
o    Recent surgery


Plan ahead:
o    Remove or leave jewelry and / or metal objects at home. Remove keys and watches before your examination. Strong magnetic fields can erase the information on credit cards. Gold wedding rings are non-magnetic and may be worn.
o    Remove eye make up, wigs, hairpieces, hair extensions and hairpins. Materials in these products can interfere with accurate interpretation of your images.
o    Patients requiring sedation. See below.
o    Bring your most recent x-ray, CT or MRI scans. Bring your health insurance information, physician referral and any necessary forms.
o    Check in 15 minutes before your scheduled appointment time to register for your MRI exam and complete screening forms.
o    Plan at least 45 – 60 additional minutes to complete the exam.


If your doctor has prescribed oral sedation or pain medication:
o    Arrive at the radiology reception desk 30 minutes before your scheduled appointment to register for your MRI exam and take your prescribed medication.
o    Avoid use of caffeinated products on the day of your exam.
o    Make arrangements to be driven home after your procedure.
o    Plan to rest for the remainder of the day. Do not drive, operate machinery or make important (legal) decisions for 24 hours following your examination or procedure.


If examination is scheduled in a hospital department and your doctor has prescribed conscious / IV sedation:
o    Do not eat or drink anything from the hour of midnight before your exam. Conscious / IV sedation requires an empty stomach.
o    Arrive at the radiology reception desk 30 minutes prior to your scheduled appointment time to register for your exam.
o    Make arrangements to be driven home after your procedure.
 

How to Prepare Child for Most MRI Exams - Child (Under 6 Years of Age)
Please call the hospital department if you think your child has a condition that might prevent a MRI exam.

Contraindications:
o    Pacemaker
o    Aneurysm clips
o    Inner ear implants
o    Bone or neuro stimulations
o    Metal shavings and / or BB's in your eyes
o    Permanent eyeliner
o    Some physical limitations
o    Recent surgery


Plan ahead:
Because motion can distort MRI images, it will be necessary for your child to remain still during his or her MRI examination. For this reason, pediatric MRI examinations are generally performed in a hospital setting where your child can be monitored under sedation.


Preparation instructions vary by the age of the child.
o    Children 2 years of age and older - Do not eat for 8 hours before a MRI exam. Drinking clear liquids is okay up to 3 hours before the procedure.
o    Children between age 6 weeks and 2 years - Do not eat for 6 hours before a MRI exam. Drinking clear liquids is okay up to 3 hours before the procedure.
o    Children under 6 weeks and premature newborns - Call the hospital MRI department for special instructions.
o    MRI examinations are best performed when children are sleepy. We recommend keeping your child awake as late as possible the night the before the test and waking them very early on the morning of their exam. For this reason, early Morning appointments are recommended. Please arrive 30 minutes prior to your child's scheduled appointment time to register at the radiology reception desk.
o    Leave valuables and metal objects at home. MRI examinations involve very strong magnetic fields. Remove keys and watches. The magnet can erase the information on credit cards.
o    Bring your child's most recent x-ray, CT or MRI scans. Bring your child's health insurance information and any necessary forms.
o    Bring a bottle or snacks for young children to drink / eat after the examination is complete.
o    Plan for at least 2 hours to complete the exam. The length of your child's scan will depend on the type of procedure, level of sedation and monitoring required. Very young children (under 6 weeks or premature newborns) require longer monitoring. This will include an overnight hospital stay.
After your child's MRI exam:
o    Your child may eat normally after a MRI examination. Children should be encouraged to drink extra fluids. This helps to flush out contrast agent if it is administered during the procedure.
o    A restful level of activity is recommended for 24 hours following any examination or procedure performed under sedation. Sedation causes drowsiness and temporarily impairs coordination. For your child's safety, bicycle riding, skating, swimming or other such activities should be avoided.
o    Always follow up with your child's physician after any diagnostic examination. The results of your child's examination will be forwarded to his or her physician, who will discuss your child's results and any treatment recommendations with you.

How to Prepare for MRI Exam of Common Bile Duct and Pancreatic Duct (MRCP)

Contraindications
Please call the MRI Center if you think you have a condition that might prevent a MRI exam:
o    Pacemaker
o    Aneurysm clips
o    Inner ear implants
o    Pregnant
o    Bone or neuro stimulations
o    Metal shavings and / or BB's in your eyes
o    Permanent eyeliner
o    Some physical limitations
o    Recent surgery

Plan ahead


Do not eat or drink after midnight before this exam. 20 minutes prior to your examination you will be given 10 to 12 ounces of an oral MR contrast fluid to drink. This medication will enable visual differentiation between the bowel stomach and ducts. Some patients may experience a mild diarrhea reaction to this contrast agent following exam. Stronger reactions are rare.


If your doctor has prescribed oral sedation or pain medication:
o    Arrive at the radiology reception desk 30 minutes before your scheduled appointment to register for your MRI exam and take your prescribed medication.
o    Avoid use of caffeinated products on the day of your exam.
o    Make arrangements to be driven home after your procedure.
o    Plan to rest for the remainder of the day. Do not drive, operate machinery or make important (legal) decisions for 24 hours following your examination or procedure.

MRI Brain - IAC


MRI is the preferred technology for brain imaging, particularly in the evaluation of suspected tumors or brain lesions. MRI is the primary tool used to detect abnormal white matter disease typical of multiple sclerosis.

MRI of the brain can examine areas hidden by CT, such as the cerebellum, brain stem, and pituitary regions. Aneurysms, vascular disease and inflammatory processes secondary to traumatic injury may be detected with MRI of the brain. Numerous congenital abnormalities are well delineated on MRI and since it emits no radiation, follow up examination usually presents no problems.

IAC MRI screens (limited study of internal auditory canals or inner ear structures and nerves associated with hearing) can clearly define the anatomy associated with hearing. At this time, IAC screens are only available at Tacoma Magnetic Imaging.

Use of a head coil during exam are usually necessary to enhance visualization of brain images and complete the study. Need for IV contrasts agent (Gadolinium) varies.


MRI Spectroscopy


Spectroscopy MRI is used to detect the chemistry of an area of the brain. This scan can further investigate an area of abnormality identified on a routine MRI scan. It can be used to differentiate radiation necrosis from recurrent tumor. It is also valuable in evaluating multiple sclerosis. No Gadolinium is injected in this exam.


MRA (Magnetic Resonance Angiography)


MRA provides MRI images of blood flow through a vessel. MRA is most frequently used to evaluate suspected narrowing (stenosis) of the carotid arteries (in the neck) and to locate suspected aneurysm in the brain. MRA is sometimes used to detect renal artery stenosis, aortic aneurysms and other vascular disease.

In some circumstances, MRA examinations, which usually do not require the use of contrast agents, may provide an alternative to more invasive angiogram / arteriogram procedures.


MRI of the Breast


Mammography photoMagnetic Resonance Imaging (MRI) is a relative newcomer to the field of breast imaging. MRI uses magnetic fields and radio frequencies to generate cross sectional images of all parts of the body.

There are several excellent uses for highly accurate MRI of the breast, which may be recommended in cases where conventional mammography and ultrasound show only vague abnormalities. MRI of the breast may also be useful in these circumstances:
o    Treatment planning in select patients diagnosed with breast cancer
o    Women who are genetically considered at high risk for the development of breast cancer
o    Women with extremely dense breast tissue difficult to visualize on a mammogram
o    Evaluation of breast implants for a possible leakage or rupture


It is important to know that MRI of the breast does not replace mammography, ultrasound and physical examination of the breast. This procedure must be referred by a breast specialist or surgeon.


MRI Abdomen


Abdominal MRI is generally used in conjunction with CT imaging to form the most complete analysis. Abdominal MRI is most frequently used to evaluate abnormalities of the gallbladder, common bile duct, liver and pancreatic ducts (MRCP or MR cholangiopancreatography).

IV contrast agent (gadolinium) injections may be necessary to enhance visualization of abdominal structures. In some cases an oral contrast may be used.
 

MRI Pelvic


MRI of the male pelvic region examines the prostate, urethra and seminal vesicles and may be used for prostate cancer staging. Ultrasound is still considered the primary imaging tool for evaluation of the testicles and scrotum.

MRI of the female pelvic region examines the uterus and ovaries and is useful in the evaluation of endometrial cancer.

MRI of the pelvis may also be used to evaluate trauma and/or abnormalities of bony structures such as avascular necrosis of the hip, joint effusions and metastatic disease.

IV contrast agent (gadolinium) injections may be necessary to enhance visualization of pelvic images.


MRI Spine & Bone Marrow


MRI is considered the standard modality for imaging of the spine and its contents. Disc herniation, spinal stenosis (narrowing of the spinal canal), nerve root impingement, sciatica and post surgical scarring can be clearly differentiated with MRI.

MRI is very sensitive to bone marrow changes due to trauma and / or metastatic disease. MRI of the bone marrow involves survey of the full (entire) spinal column and pelvic girdle. Bone marrow examinations require 60 to 90 minutes to complete.

IV contrast agent (gadolinium) injections and use of a spine coil are generally necessary to enhance visualization of spine images post surgery and for complete analysis of spinal cord lesions.


MRI Joint & Extremities


Due to MRI's ability to define dissimilar types of tissue, cartilage, and bone, MRI is the preferred modality for imaging joints such as shoulders, knees, hands / wrists, feet and ankles. MRI's clarity in studies of traumatic injury (i.e. rotator cuff, meniscus tears, ligament tears, carpal tunnel syndrome), suspected tumor, cyst and arthritic processes contribute to a more accurate diagnosis.

Reinjury of the rotator cuff or knee following previous surgical repair is best evaluated with MR arthrography, which involves intraarticular gadolinium injection into the joint, itself, to better visualize the tendons and cartilage that make the joint. These injections are administered by the radiologist using fluoroscopic x-ray as a visual guidance tool. MRI exam of the joint follows injection.

IV contrast agent (gadolinium) injections and the use of a joint/extremity coils may be necessary to enhance visualization of joint / extremity images.


TMJ


The most common cause of TMJ (temporomandibular jaw dysfunction) pain is displacement of the meniscus or disc, which fills the joint space. MRI is the only imaging modality where the position of the disc and its dynamic motion can be visualized while the jaw is open and closed.

Use of TMJ coils are necessary to enhance visualization of both sides of the jaw joint.