• Medical Associates of Davie
• Winston-Salem Health Care

What is an MRI of the body?
MRI uses radio frequency waves and a strong magnetic field rather than X-rays to provide remarkably clear and detailed pictures of internal organs and tissues. The technique has proven very valuable for the diagnosis of a broad range of pathologic conditions in all parts of the body including cancer, heart and vascular disease, stroke, joint and musculoskeletal disorders. MRI requires specialized equipment and expertise and allows evaluation of some body structures that may not be as visible with other imaging methods.

What are some common uses of the MRI procedure?
An MRI can give clear pictures of soft-tissue structures near and around bones, it is the most sensitive exam for spinal and joint problems. MRI is widely used to diagnose sports-related injuries, especially those affecting the knee, shoulder, hip, elbow and wrist. The images allow the physician to see even very small tears and injuries to ligaments and muscles.

In addition, MRI of the heart, aorta, coronary arteries and blood vessels is a fast, non-invasive tool for diagnosing coronary artery disease and heart problems. Physicians can examine the size and thickness of the chambers of the heart and determine the extent of damage caused by a heart attack or progressive heart disease.

Organs of the chest and abdomen, e.g., lungs, liver, kidney, spleen, pancreas and abdominal vessels, can be examined in high detail with an MRI, enabling the diagnosis and evaluation of tumors and functional disorders. MRI is growing in popularity as an alternative to traditional X-ray mammography in early diagnosis of breast cancer. Because no radiation exposure is involved, an MRI is often the preferred diagnostic tool for examination of the male and female reproductive systems, pelvis and hips and the bladder.

How should I prepare for the procedure?
Because the strong magnetic field used for an MRI, it pulls on any ferromagnetic metal object implanted in the body, MRI staff asks whether you have a prosthetic hip, heart pacemaker (or artificial heart valve), implanted port, infusion catheter (brand names Port-o-cath, Infusaport and LifePort), intrauterine device (IUD), any metal plates, pins screws or surgical staples in your body. In most cases surgical staples, plates, pins and screws pose no risk during an MRI if they have been in place for more than 4 to 6 weeks. Tattoos and permanent eyeliner may create a problem. The patient is asked if you ever had a bullet or shrapnel in your body or ever worked with metal. If there is any question of metal fragments, the patient is asked to have an X-ray that detects any such metal objects. Tooth fillings are usually not affected by the magnetic field but they may distort images of the facial area or brain, so the radiologist should be aware of them. The same is true of braces, which may make it hard to tune the MRI unit to your body. The patient is asked to remove anything that might degrade MRI images of the head, including hairpins, jewelry, eyeglasses, hearing aids and any removable dental work.

The radiologist or technologist may ask about drug allergies and whether head surgery has been performed in the past. If you might be pregnant, this should be mentioned. Some patients who undergo an MRI in an enclosed unit may feel confined or claustrophobic. If you are not easily reassured, a sedative may be administered. Roughly one in 20 patients require medication to reduce the anxiety associated with claustrophobia.

How is the procedure performed?
The patient is placed on a sliding table and positioned comfortably for the MRI examination. Then the technologist leaves the room and the individual MRI sequences are performed. The patient is able to communicate with the technologist at any time using an intercom. Many MRI centers allow a friend or, if a child is being examined, a parent to stay in the room. Depending on how many images are needed, the exam generally takes 15 to 45 minutes, although a detailed study may take longer. The patient is asked not to move during the actual imaging process, but between sequences some movement is allowed. Patients are generally required to remain still for only a few seconds to a few minutes at a time.

Depending on the part of the body being examined, a contrast material (usually gadolinium) may be used to enhance the visibility of certain tissues or blood vessels. A small needle connected to an intravenous line is placed in an arm or hand vein. A saline solution drips through the intravenous line to prevent clotting until the contrast material is injected about two-thirds of the way through the exam.