Locations & Hours | Radiology Services & Procedures | Insurance Info | Policies & Payments Magnetic Resonance Imaging (MRI) What is MRI? MRI is an advanced means of imaging the body using a combination of very strong magnetic fields and radio waves. It gives the radiologist information that is not available from other types of examinations, such as ultrasound and CT scan. This certainly does not mean that it replaces all other types of imaging, and, in some cases, other examinations are preferred depending on the nature of your symptoms and other information supplied by your personal physician. The advantages of MRI are that it can differentiate different types of disease processes better than any other type of medical imaging, it can scan in any direction through the body, and it does not use x-rays (which can have harmful side effects if not carefully monitored). The disadvantages of MRI are that it is more expensive than some other tests due to the extremely sophisticated nature of the equipment and the expertise required to perform the scans, that it takes longer to perform than most other imaging procedures, that some patients experience claustrophobia due to the confining environment of the magnet, and that it is noisier than most other tests. Some MRI exams can be performed on "open" magnets that are less likely to cause claustrophobia. MRI is used for scanning all parts of the body, most commonly the head, spine and joints. However, it is used with increasing frequency to evaluate the gallbladder and bile ducts, the arteries, the heart and abdomen. What is the MRI exam like? You will be asked to complete a preliminary questionnaire. This questionnaire is administered primarily for two reasons: first, to assure our staff that you have no health condition(s) or personal articles on your body that would pose a risk to your safety during the procedure; second, to provide information that allows our radiologists to interpret your examination more accurately. After this, you will be asked to remove your clothing, put on a hospital gown, and remove all personal articles that could be attracted to a magnet and/or cause problems in interpretation of the study. After that, you will be placed in the magnet and given earplugs to protect your hearing from the noise caused by the function of the magnet system. Most MRI examinations require little or no preparation. In many cases, you will receive an intravenous injection of MR contrast material. This material is well tolerated and safe when compared to the contrast materials commonly used in CT scans and routine x-rays. Adverse reactions do occur, but they are less frequent and less severe than with other contrast agents. The typical exam lasts from about 30 to 45 minutes, but depending upon the amount of information that your referring physician wants and the complexity of the exam, you may be in the magnet longer. It is crucial that you remain still during the examination, so please inform the technologist of any problems that may prevent you from remaining in the same position for the duration of the exam. It is a good idea to go to the bathroom immediately prior to the exam. After the exam has been completed, our radiologists will review the images and issue a formal written report to your doctor. Is MRI safe? MRI does not use x-rays to produce its images. Instead, it relies on magnetic waves and radiofrequency waves (which are in the same spectrum as those used in the communications industry). Unlike x-rays, these waves have no known harmful effects on living tissues when used in approved amounts. MR has been in common clinical use for over a decade now, and no adverse effects from the magnetic or radiofrequency waves have been reported. There are other potential problems to address, however. In the magnets staffed by Radiology Alliance, P.C., you may be placed in a magnetic field up to 10.000 times the earth's gravitational field. While the strength of the magnetic field itself will not harm your tissues, objects in the immediate environment that might be attracted to the magnet can become deadly missiles. Therefore, our staffs are trained to screen all patients, as well as other hospital personnel, for potentially dangerous magnetic-susceptible objects on their persons or in their immediate control. The waves generated by an MR scanner may induce electric currents in monitoring wires or other life support devices. Such wires and leads on monitoring devices must be carefully positioned so as not to lead to thermal injury. Our MR staffs are trained to avoid these problems, but complications can occasionally arise despite apparent adequate precautions. Other seemingly unimportant or overlooked metallic substances, such as tattoos or metallic foreign objects, can cause heating and unpleasant sensations but rarely cause serious harm. One significant exception is the presence of metallic fragments or shrapnel around the eyes. Because of the delicate nature of the eyes, any movement of such magnetic-susceptible metallic fragments caused by the strong magnetic force can lead to permanent blindness. This is one more reason why you will be questioned before you enter the magnetic environment. Is MRI safe for patients with metallic implants or prostheses? In general, MRI is quite safe for the majority of patients who have surgically implanted materials, surgical clips or prostheses such as hip or knee replacements. There are some important exceptions, however: Patients with cardiac pacemakers are generally not allowed in the magnet. The radiofrequency waves may cause the pacemaker to malfunction, leading to life-threatening alterations of the heart rate. Patients with implanted electronically or magnetically operated devices, such as cochlear (ear) implants or neurostimulators, should only be placed in the magnet in cases of extreme urgency since these devices can be disabled by the magnetic or radiofrequency waves used in MRI. Carotid artery aneurysm clips have been of special concern to radiologists monitoring the safety of patients ever since clinical MRI became available. Early reports stressed the risk of placing such patients in the magnet. However, it is now accepted that virtually all of these clips - with the exception of one specific type: the Poppen-Blaylock clamp - are safe for use at clinically available magnetic field strengths. Nevertheless, if you know that you have had a carotid or intracranial aneurysm clipped in the past, it may facilitate the exam if you can contact the surgeon who performed this surgery, ask him or her specifically which type of clamp was used, and bring written confirmation with you to the MRI test site. Please bear in mind that your safety is our most important consideration, so please understand if the staff considers further documentation necessary. Postoperative patients can generally be scanned immediately after surgery since the vast majority of surgically implanted materials are not attracted to the magnet. However, in certain cases it is advisable to wait 6 - 8 weeks to allow time for scar tissue surrounding the implanted material to anchor it in place more securely. There are hundreds of different types of surgically implanted devices on the market today. If you or your personal physician can supply the information regarding the exact identity of the implant, it will be of great help to the staff in assuring your safety. We know that most of these pose no cause for alarm or reason to cancel the procedure, but in unusual cases it may be necessary to postpone the test until the exact identity of the object in question can be identified. Please understand that while the majority of implant devices are quite safe and do not preclude your being scanned, such objects may degrade the image to the point that no useful information can be obtained from the procedure. Unfortunately, this is not always apparent before the exam is started. Is MRI safe for pregnant patients? The Committee on Safety of the Society for Magnetic Resonance Imaging has stated that "...to date, there has been no indication that the use of clinical MR imaging during pregnancy has produced deleterious effects." Like any other procedure, it should be used advisedly, especially during pregnancy. However, it is generally considered acceptable if the information to be gained is crucial to the health of the mother or fetus and that information cannot be obtained by other clinical tests or imaging procedures not using x-rays.