Magnetic resonance imaging
Magnetic resonance imaging (MRI), is a medical imaging technique used in radiology to visualize detailed internal structures using magnetic radiation. MRI provides real-time, three-dimensional views of body organs with good soft tissue contrast, making visualization of brain, spine, muscles, joints and other structures excellent. It is multiplanar, which means that images can be obtained in multiple body planes without changing positions. MRI findings are based on compilation of sequences that are an ordered combination of RF and gradient pulses designed to acquire the data to form the image.
When undergoing MRI examination, the patient is asked to remove metallic objects including watches, jewellery and piercings. Surgical implants and other foreign bodies must be carefully evaluated for MRI safety. The patient will hear loud noises and ear plugs are usually provided. Intravenous contrast media may be used for enhancement of the study.
Common clinical applications
- Brain MRI with diffusion/perfusion studies
- Spinal MRI
- Abdominal MRI to assess liver, spleen, kidneys, MR cholangiography, etc
- Neck MRI
- Magnetic resonance angiography
- Cardiac MRI
- Extremities for joints, muscles, bone disorders
- Chest/mediastinal MRI
- Image-guided interventional procedures
- MRI is generally safe to the patient and there is no radiation exposure.
- Injury or death may be caused by performing MRI on patients with metallic implants such as pacemakers, surgical clips or other foreign bodies. Extreme caution must be used to avoid MRI in these patients.
- Care must also be taken not to bring any metallic objects into the MRI room, as they may cause injury through projectile motion into the magnet.
- Claustrophobia is experienced by some patients during examination; this can be managed with sedation or anesthesia if required.
- No side effects have been seen in pregnant women or children.