Magnetic resonance imaging, or MRI, is a way of examining parts of the body by taking images of it by using powerful magnetic fields. MRI can be used for both medical and scientific purposes because of the highly refined pictures these scans render.With them, it's possible to see through the skull and get a clear picture of the brain's soft tissue structures. MRI is commonly used to diagnose and follow the progress of such conditions as Alzheimer’s, strokes, meningitis, and brain tumors.
Safety
Unlike CT scans or traditional X-rays that use ionizing radiation that can be harmful in certain instances, the magnetic fields and non-ionizing radiation used by MRI scans have no known health risks for healthy individuals. Another aspect that makes MRI a safe tool for diagnosis is that the process is completely non-evasive. MRI is also safe for pregnant women and fetuses. However, there are still some patients that should not be studied with MRI. Dr. GN Levine and colleagues stated in a study published in “Circulation” in 2007 that patients with cochlear implants, insulin pumps, or pacemakers should not be subjected to MRI. The authors of the study formed this recommendation after noticing that several patients that had pacemakers experienced arrhythmia, and in some instances, even death, when MRI scans were conducted on them without appropriate precautions.
Accuracy
MRI is a precise and accurate method of diagnosis. MRI’s spatial resolution, or ability to distinguish two separate structures located within small distances from each other, is comparable to that of other imaging techniques such as Computer Topography (CT), according to Chelsea S. Kidwell, M.D., and colleagues. Yet, its contrast resolution, or the ability to distinguish the differences between two similar looking, but not identical tissues, is far better. These findings were first published in the October of 2004 in the “Journal of American Medical Association.” MRI is particularly useful for spotting tumors and other lesions, says the Encyclopedia of Surgery. It notes that MRI might be able to detect these type of abnormalities earlier than some other imaging tools.
Scope
All parts of the body can be studied using MRI. Importantly, MRI images are not affected by, for example, bones. MRI also allow doctors to receive three-dimensional images through computers that combine series of two-dimensional images taken by the machine. Unlike some other imaging techniques, MRI can provide images in multiple planes; a feature that makes the technique even more versatile.
References
- Surgery Encyclopedia: Magnetic resonance imaging
- “Circulation” Journal; Safety of magnetic resonance imaging in patients with cardiovascular devices; GN Levine, MD et al., DOI: 10.1161, 2007
- "JAMA"; Comparison of MRI and CT for Detection of Acute Intracerebral Hemorrhage; Chelsea S. Kidwell, et al; Oct. 20, 2004.
- Medline Plus: Head MRI
- University of Maryland Medical Center: Head MRI
