How should I prepare for the procedure?
There is no preparation required for an MRI. You may continue eating, drinking and all physical activity as you normally would.You will be asked to remove all metal objects including jewelry, watches and hairpins. Dyes used in tattoos may contain iron and could heat up during MRI, but this is rarely a problem. You may wear a hospital gown during the exam, or may be allowed to keep your own clothing if it is loose-fitting and has no metal fasteners. If you might be pregnant you should mention this to MRI staff.The strong magnetic field in MRI can interfere with the operation of an implanted cardiac pacemaker or other medical device. Our staff will ask whether you have a pacemaker, artificial heart valve, implanted drug infusion port, artificial limb, intrauterine device, or any metal pins, screws, plates or surgical staples. In most cases, metal objects used in orthopedic surgery pose no risk during MRI. Other objects that may prohibit MRI are an inner ear implant, clips used on brain aneurysms, and a recently placed artificial joint. Sheet metal workers and others who might have metal objects such as a bullet or shrapnel in their body should have an x-ray performed before MRI.Because some MRI studies use oral or injected contrast to obtain the clearest images, the radiologist or technologist will ask you about your allergies of any kind such as hay fever, hives, allergic asthma or allergy to food or medications. The radiologist should know of any serious health problems because some of them—such as kidney disease or sickle cell anemia—may prevent you from having MRI with contrast. People who tend to be claustrophobic might become uncomfortable and may find it hard to lie still during the exam. A sedative will relieve anxiety in this situation, let either your physician or our staff know when you schedule your exam if you feel you may need to have one prescribed.
What does the equipment look like?
Photographs of the actual MRI equipment we use at Bethesda MRI are featured throughout our website. It consists of a cylinder-shaped compartment that contains a very strong magnet in which the patient must lie still for periods lasting several minutes. Our high field MRI machines are less confining than most high field magnets and are made in a way that eliminates much of the noise other MRI machines produce. Our MRI is built with a wider tunnel than most and it is ultra short so you experience a much more open feeling than in other high field MRI machines. Our equipment is brand new, state of the art and produces the best possible image quality.
How does the procedure work?
Among imaging methods, MRI is unique in that it does not depend on ionizing radiation, as does the conventional x-ray examination. The basis of MRI is to direct radio waves at protons, particles that help make up the nucleus of hydrogen atoms. When this is done in a strong magnetic field generated by a large magnet that surrounds the patient's body, the protons are alternately "excited" and "relaxed," emitting signals that are processed by a computer program to form images. Because protons are most abundant in the hydrogen atoms of water (the "H" in H20), MRI images depict differences in the content and distribution of water in various tissues. With MRI, different types of tissue within the same body structure are clearly displayed in fine anatomic detail. In the spine, for instance, fatty tissue, cerebspironal fluid, and the central portion of the material making up the intervertebral disks contain considerable water, more than is found in bone, cartilage, and nerve tissue. MRI is well suited to detecting conditions that increase the amount of fluid, such as tumors, inflammation, and infection.A typical MRI exam includes two to six imaging sequences, which produce sectional views or "slices" of the spine in different planes: left to right, front to back, upper to lower. The sections are often about a quarter-inch apart, providing a detailed look at the tissues making up the spinal column. The images may be stored in a computer and subsequently viewed on screen, or they may be printed on film much like a conventional x-ray. Depending on the location of symptoms, you probably will have only part of your spine imaged: the cervical (neck) portion, the thoracic (chest) spine, or the lumbar (lower) spine.
What will my experience be like?
You will lie on your back on a cushioned table that can be moved forward and backward, into and out of the MRI tunnel. The table is moved by an automatic mechanism operated by the technologist. Bolsters or cushions are used to maintain proper positioning and to make you as comfortable as possible, and an “antenna” may be placed around the area to be scanned. When all is ready, a radiologic technologist will leave the examining room, but you will be able to communicate with the technologist at any time using a two-way intercom installed in the MRI unit. The technologist will watch you through a glass window next to the examining room. You are permitted to have a friend or family member remain in the MRI suite with you, or a parent if a child is being examined. An MRI study generally takes 15 to 45 minutes, although only a fraction of that time is needed for the actual imaging. You will be instructed not to move during imaging, because motion will blur the images. Your technologists will inform you when images are being recorded, and you will hear tapping or thumping sounds whenever the coils creating a secondary magnetic field are turned on. Each imaging sequence takes from a few seconds to a few minutes, so that you will be able to relax at intervals during the examination. When it is completed you will wait a short time on the table while the images are examined; occasionally additional images are needed.
Is the procedure painful?
MRI causes no pain, although some patients find it uncomfortable to stay still while imaging is taking place. A few patients are bothered by a closed-in feeling similar to claustrophobia, however, this usually can be relieved by taking a sedative. It is rare that a patient is unable to tolerate MRI of any type and requires a different form of imaging.
When first entering the MR unit, you may hear a fan and feel air moving. No earplugs are necessary at our center but we do provide a stereo headset if you would like to listen to one of our music CD’s or bring one of your own. If contrast is to be injected, you may feel a brief pain from the needle stick and a sense of warmth when the material is injected—which takes one to two minutes.
No period of recovery is needed after MRI unless you have received a sedative. You may resume normal activities, your usual diet, and needed medications immediately.
For what condition is an MRI useful?
MRI is effective in the clinical evaluation of the following conditions:
- Liver and Other Abdominal Diseases
- Knee and Shoulder Injuries
- Musculoskeletal Disorders
- Brain Disorders
- Traumatic Injuries
- Tumor Detection
- Spine Diseases
- Blood Flow and Vessel Disorders
Who interprets the results and how do I get them?
The radiologist, often with expertise in the area you are concerned with, will view and interpret your images. A preliminary interpretation may be available for your referring physician shortly after the exam, and a formal report of the complete results will be sent within 24 hours. Your primary care physician or referring specialist will discuss the findings of the MRI examination with you. If requested, films can also be sent to your doctor.
What are the benefits vs. risks?
- MRI is an excellent method of obtaining clear, detailed images of the bony structures and soft tissues. It demonstrates abnormalities, injuries and diseases that may not be visualized with other imaging methods.
- MRI is a noninvasive study that—unlike conventional x-rays, CT scanning, and myelography—does not require exposure to radiation.
- This method takes little time to carry out, making it very useful for evaluating people who have been injured.
- The contrast sometimes used for MRI does not contain iodine, and therefore it is far less likely to produce an allergic reaction than the contrast materials used for conventional x-rays and CT scanning.
- MRI is able to detect subtle changes that may be an early stage of infection or tumor. The procedure may be better than CT scanning for evaluating tumors, absesses, and other masses.
- An iron-containing implant or cardiac pacemaker may be affected by the strong pull of the magnetic field.
What are the limitations of MR Imaging?
MRI generally is not done in the first 12 weeks of pregnancy. Radiologists prefer to use other methods such as ultrasound imaging in pregnant women unless no examination other than MRI will do. It may not be possible to perform MRI in a very obese patient, these patients may be accommodated in an open MRI but the magnet strength is less in an open MRI. The presence of an implant or other metallic object often makes it difficult to obtain clear images, and patient movement can have the same effect. A patient with severe pain may not be able to lie still during imaging.The MRI findings by themselves do not establish an absolute diagnosis, but in most situations the findings will suggest the correct diagnosis. The images must be interpreted along with the patient's history, physical findings, and information from other tests. MRI may be more costly than other imaging methods including CT scanning. At Bethesda MRI children are welcome, however, we do not see children under the age of two years who require a contrast injection.
How experienced is the staff?
Our technologists have been thoroughly trained, are certified and have years of experience. They have been hired by Bethesda MRI for their expertise and excellence in customer service.