The brain together with brain stem and spinal cord body's central nervous system. The brainstem is the term for the transition between the brain and spinal cord, here are centers that control such cardiovascular and respiratory functions. The brain is protected by the skull and a fluid filled cavity surrounding the brain mass. The brain consists of a right and left brain. The outer part of the brain, the cerebral cortex or gray matter, controls most of the body's functions such as vision, hearing, speech, thought, movement, etc. The inner part of the brain, the white matter, consisting primarily of neural pathways linking the different parts of brain together and which causes nerve impulses up and down the spinal cord.
Neural pathways from the cortex cross over to the opposite side of the white substance. Damage to the left hemisphere thus leads to functional impairment in the right side of the body. Conversely causes damage to the right hemisphere to the functional impairment of the left side of the body. The brain is surrounded by a fluid, cerebrospinal fluid, which also surrounds the spinal cord. The inserts in the lower back can drain some of the fluid to check for signs of disease of the central nervous system.
What is MRI?
Magnetic resonance imaging MRI shortened. MRI machine consists of a powerful magnet (more magnetic coils), a radio transmitter, a radio receiver (antenna) and a computer. These components work together in such a way that it produces images of the interior of the body. The machine is open at both ends and is well lit. When the investigation is done, you're inside the machine and are in a strong magnetic field. The machine simultaneously transmits radio waves towards the area to be examined. Depending on the tissue in the body these radio waves hit, different amounts of radio waves captured, absorbed. In the strong magnetic field detected by this antenna / radio receiver in your computer. The signals in this way is captured, sent to the computer which produce images.
Computer technology makes it possible to produce images in many planes as well as in three-dimensional images. There are many variations and special techniques which can be used to affect the MRI signal to emphasize specific types of tissues. Procedures for image acquisition varies from center to center. MRI is still under development and improvement.
In contrast to CT and X-rays are not ionizing radiation. There is no evidence of harmful effects on humans of the magnetic field and radio waves used for the MRI.
MRI of the brain
As regards procedures for MR image recording of the brain, these vary from center to center. Images are captured in different directions. Liquid blood can be detected so that the larger arteries (arteries) and veins appear clear without contrast administration. White and gray matter inseparable, both appear also with a different density than cerebrospinal fluid. The need for contrast enhancement with intravenous contrast agents is smaller with MRI than CT. However, specific MRI contrast agents may be used if desired, these contrast agents are very safe to use.
In a normal examination are normal conditions in the soft tissues such as the brain, the space around the brain, nerves and blood vessels. A normal MRI also showed that the arteries are normal size, appearance and blood flow.
Usually it is not required with dietary measures or other preparations. Patients with pacemakers, cochlear implant (apparatus of the middle ear) and metal clip attached to the blood vessels in the brain after surgery for subarachnoid hemorrhage, can not be performed MR. The same may be true for patients with implanted drug pumps and nerve stimulators. Should you, for example. a metal splinter in your eye, you know. Do you have other metal implants, you should ask your doctor or nurse if it has any significance.
Hearing aids, dentures, jewelry, piercing, hair pin, wig, etc. must be removed before the survey. Certain types of cosmetics (mascara) contains bits of metal and can cause discomfort - you should not wear make-up before the study.
Most MRI machines are tunnel-shaped with an opening at both ends. Modern magnets are shorter and wider than the older versions. As a result, claustrophobia become a minor problem in MR investigations. During the survey stock machine high bank sounds. Earplugs and / or headphones where you hear music, routinely used to suppress the noise. If only a small area that is desired pictured, added an antenna that captures radio wave signals directly to the skin of the part to be examined. At the head examination antennas form of a cage ("birdcage") which head is inserted in.
Although modern MRI machines are more open and less frequent and claustrophobia than older versions, there are some patients who experience survey uncomfortable. To mitigate claustrophobia feeling may in some patients be necessary to give a sedative. Bidirectional communication with the investigators created - you can thus talk to them even if they are sitting in a control room adjacent to the examination room. Try and relax as best you can. The survey is painless.
You lying electric bench that has been specially designed. If you are comfortable, I move the bench to the machine. You are very important to lie still during the test it, but the image so that sharp. In some cases, the contrast of the given, to enhance the image. Learning time is different, it takes 20-45 minutes usually.
What to MRI of the brain?
The study is relevant for investigating a wide range of conditions: Brain tumors , cancer spread to the brain (metastases), multiple sclerosis , stroke and brain drip , infections within the cranium (eg encephalitis ), epilepsy , diseases of specific brain regions, congenital anomalies, vague neurological disease, acoustic neuroma . A normal examination will in most cases rule out such diseases.
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