What is Magnetic Resonance Imaging (MRI)?
Magnetic resonance imaging (MRI) uses strong magnet and radio waves to provide clear and detailed diagnostic images of internal body organs and tissues. MRI is a valuable tool for the diagnosis of a broad range of conditions, including cancer, heart and vascular disease, stroke and joint and musculoskeletal disorders. MRI allows evaluation of some body structures that may not be as visible with other diagnostic imaging methods.
What are some common uses of MRI?
MRI is frequently used for imaging of the musculoskeletal system. MRI is often used to study the knee, ankle, foot, shoulder, elbow, wrist and hand. MRI is also a highly accurate method for evaluation of soft tissue structures such as tendons and ligaments, which are seen in great detail. Even subtle injuries are easily detected. In addition, MRI is used for the diagnosis of spinal problems including disc herniation, spinal stenosis and spinal tumors.
MRI is used for imaging of the heart. MRI of the heart, aorta, coronary arteries and blood vessels is a tool for diagnosing coronary artery disease and other heart problems. Doctors can examine the size and thickness of the chambers of the heart and determine the extent of damage caused by a heart attack or heart disease. MRI is also used for imaging of cancer and functional disorders. Organs of the chest and abdomen such as the liver, lungs, kidney and other abdominal organs can be examined in great detail with MRI. This aids in the diagnosis and evaluation of tumors and functional disorders. In the early diagnosis of breast cancer, MRI is an alternative to traditional x-ray mammography. Furthermore because there no radiation exposure is involved, MRI is often used for examination of the male and female reproductive systems.
What is MR Angiography (MRA)?
MR angiography (MRA) uses a powerful magnetic field, radio frequency waves and a computer to evaluate blood vessels and help identify abnormalities or diagnose atherosclerotic (plaque) disease. This exam does not use ionizing radiation and may require an injection of a contrast material called gadolinium, which is less likely to cause an allergic reaction than iodinated contrast material. If needed, the contrast material is usually administered through a small intravenous (IV) catheter placed in a vein in the arm.
What are some common uses of MRA?
MRA is used to examine blood vessels in key areas of the body, including the brain, neck, heart, abdomen, pelvis and extremities (arms, legs, feet and hands).
How should I prepare?
Before your MRI exam, remove all accessories including hair pins, jewelry, eyeglasses, hearing aids, wigs and dentures. During the exam, these metal objects may interfere with the magnetic field, affecting the quality of the MRI images taken. Notify your technologist if you have:
- any prosthetic joints – hip, knee
- a heart pacemaker (or artificial heart valve), defibrillator or artificial heart value
- an intrauterine device (IUD),
- any metal plates, pins, screws or surgical staples in your body
- tattoos and permanent make-up
- a bullet or shrapnel in your body, or ever worked with metal
- if you might be pregnant or suspect you may be pregnant
What should I expect during this procedure?
Depending on how many images are needed, the exam generally takes 15 to 45 minutes. However, very detailed studies may take longer. You must lie down on a sliding table and be comfortably positioned. Even though the technologist must leave the room, you will be able to communicate with them at any time using an intercom. You will be asked to remain still during the actual imaging process; however, between sequences, which last between 2-15 minutes, slight movement is allowed. Depending on the part of the body being examined, a contrast material may be used to enhance the visibility of certain tissues or blood vessels. A small needle is placed in your arm or hand vein and a saline solution IV drip will run through the intravenous line to prevent clotting. About two-thirds of the way through the exam, the contrast material is injected.
What will I experience during this procedure?
MRI is painless. Some claustrophobic patients may experience a “closed in” feeling. If this is a concern, a sedative may be administered. Also, newer open MRI machines have helped to alleviate this reaction. You will hear loud tapping or thumping during the exam. Earplugs or earphones may be provided to you. You may feel warmth in the area being examined. This is normal. If a contrast injection is needed, there may be some discomfort at the injection site. You may also feel a cool sensation at the site during the injection.