MRI is noninvasive and does not use ionizing radiation that helps physicians diagnose and treat medical conditions.
Magnetic resonance imaging (MRI) uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of the body's internal structures that are clearer, more detailed and more likely in some instances to identify and accurately characterize disease than other imaging methods.
It is used to evaluate the body for a variety of conditions, including tumors and diseases of the liver, heart, and bowel. It may also be used to monitor an unborn child in the womb.
Why should I do it ?
MR imaging of the chest is performed to:
- Assess abnormal masses, including cancer of the lungs or other tissues, which either cannot be assessed adequately with other imaging modalities (typically CT) or which are particularly well-suited to MR imaging.
- Determine tumor size, extent, and the degree of spread to adjacent structures.
- Assess the anatomy and function of the heart and its component structures (valves, etc.).
- Assess myocardial perfusion (blood flow to the heart) and myocardial infarct (scar in the heart muscle due to prior obstruction of blood flow).
- Determine blood flow dynamics in the vessels and heart chambers.
- Display lymph nodes and blood vessels, including vascular and lymphatic malformations of the chest.
- Assess disorders of the chest bones (vertebrae, ribs and sternum) and chest wall soft tissue (muscles and fat).
- Assess for pericardial (thin sac around the heart) disease.
- Characterize mediastinal or pleural lesions seen by other imaging modalities, such as chest x-ray or CT.
Any preparations needed?
- You may need to wear a gown, or you may be allowed to wear your own clothing if it is loose-fitting and has no metal fasteners.
Guidelines about eating and drinking before an MRI vary between specific exams and facilities. Unless you are told otherwise, take food and medications as usual.
- Tell the technologist or radiologist if you have any serious health problems or recently had surgery.
- If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your doctor to prescribe a mild sedative prior to your exam.
Leave all jewelry and other accessories at home or remove them prior to the MRI scan. Metal and electronic items can interfere with the magnetic field of the MRI unit, and they are not allowed in the exam room. They may cause burns or become harmful projectiles within the MRI scanner room. These items include:
- jewelry, watches, credit cards and hearing aids, all of which can be damaged
- pins, hairpins, metal zippers and similar metallic items, which can distort MRI images.
- removable dental work
- pens, pocket knives and eyeglasses
- body piercings
- Mobile phones, electronic watches and tracking devices.
- Do not prepare food for others that requires prolonged handling with bare hands.
In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the following implants may not be scanned and should not enter the MRI scanning area without first being evaluated for safety:
- some cochlear (ear) implants
- some types of clips used for brain aneurysms
- some types of metal coils placed within blood vessels
- some older cardiac defibrillators and pacemakers
Tell the technologist if you have medical or electronic devices in your body. These devices may interfere with the exam or pose a risk. Many implanted devices will have a pamphlet explaining the MRI risks for that particular device. If you have the pamphlet, bring it to the attention of the scheduler before the exam. MRI cannot be performed without confirmation and documentation of the type of implant and MRI compatibility. You should also bring any pamphlet to your exam in case the
- Tell the technologist or radiologist about any shrapnel, bullets, or other metal that may be in your body. Foreign bodies near and especially lodged in the eyes are very important because they may move or heat up during the scan and cause blindness. Dyes used in tattoos may contain iron and could heat up during an MRI scan. This is rare. Tooth fillings, braces, eyeshadows and other cosmetics usually are not affected by the magnetic field. However, they may distort images of the facial area or brain. Tell the radiologist about them.