Magnetic resonance imaging, or MRI, is a widely used medical imaging method. This tool uses magnets and radio waves to create pictures of the soft tissue of the human brain. These images can be from any angle and direction. MRI is safe and non-invasive and has been used to diagnose and follow numerous medical conditions. It can detect such abnormalities as infections, tumors, bleeding, swelling and cell death.
Normal and Abnormal MRI Results
In a normal MRI scan, the left and right sides of the brain should look nearly identical, and the image colors should be different shades of gray. Dark or white areas can suggest a tumor or bleeding. Blood vessels should not be enlarged or narrowed. Yet, it should be noted that MRI tests brain structure and not brain functions. Thus, it is possible for the MRI scans to look completely normal while the patient still shows abnormal brain functionsm as shown by M.-L. Kaipio, Ph.D., and colleagues in a study published in the "NeuroReport" Journal in May 2000.
Blood Vessel Diseases
MRI is an excellent method for detecting abnormalities in blood vessels. One of these abnormalities in a brain aneurysm in which the wall of an artery balloons out. If left untreated, aneurysm can lead to a stroke and bleeding into the brains. Since small aneurysm does not usually cause any symptoms according to the American Heart Organization, it is difficult to know whether a person suffers from this condition. A larger aneurysm usually causes headaches. Such conditions as high blood pressure put a person at risk for it. MRI can be used to diagnose this condition and also to see if the aneurysm is enlarging.
Brain Tumor
Brain tumor symptoms vary significantly depending on the size and the location of the tumor. Moreover, such typical signs of brain tumors as headaches, nausea and vomiting are seen in numerous other conditions as well. Thus, MRI is needed to verify the diagnosis. It is also required before the surgery to show the exact location and size of the tumor to the surgeons. After the surgery, MRI can be used to make sure that the tumor has not reappeared.
Alzheimer's Disease
Alzheimer's disease, or AD, is the most common form of dementia, characterized by severe memory difficulties. The overall shrinkage of brain tissue is a hallmark sign of AD. This is especially easy to see in the hippocampus, an area of the brain that is vital for memory. MRI can detect the cell death typical for AD quite easily, as shown by Dr. Olivier Colliot and colleagues in a study published in the "Radiology" journal in July 2008.
Multiple Sclerosis
Multiple sclerosis, or MS, is a chronic inflammatory disorder of the central nervous system. MS diagnosis is based on patient's medical history, neurological exams and MRI findings. In order to make MS diagnosis, at least two areas needs to be abnormal in the MRI scans. MRI is among the best tools to diagnose MS. Yet approximately 5 percent of the MS patients do not show any abnormalities in their MRI scans. Moreover, as shown by Dr. E. M. Frohman and colleagues in a study published in the "Neurology" Journal in 2003, the abnormal MRI findings seen in MS are not unique and can be seen in some other diseases as well. Thus, in order to confirm the diagnosis, neurological exams are needed in addition to MRI scans.
References
- RadiologyInfo.org: Magnetic Resonance Imaging
- "Neuroreport"; Increased distractibility in closed head injury as revealed by event-related potentials; M.L. Kaipio, et al; May 15, 2000
- "Radiology"; Discrimination between Alzheimer Disease, Mild Cognitive Impairment, and Normal Aging by Using Automated Segmentation of the Hippocampus; Olivier Colliot, et al; July 2008
- "Neurology Journal"; The Utility of MRI in Suspected MS;. M. Frohman et al.; vol. 61 2003
- American Heart Organization: Aneurysm, Brain
