The magnetic resonance imaging (MRI) does not use, unlike the scanner, X-ray
The magnetic resonance imaging (MRI) does not use, unlike the scanner, X-ray Its principle is based on the magnetic properties of an atom, hydrogen content, to varying degrees, in all tissues of the body. Using very strong magnets, the protons of the hydrogen atoms of the body are stimulated simultaneously, which has the effect of orienting all the hydrogen atoms in the same direction. Once this first step is completed, the atoms are brought into resonance by subjecting them to an excitation by a magnetic field (radio frequency). At the cessation of stimulation, the atoms restore energy whose intensity is measured and analyzed. Since all tissues do not contain the same amount of hydrogen atoms, the energy levels differ depending restored tissue composition. The analysis of these data by computers can reconstruct images in 2 and 3 dimensions and in all three planes of space. Because of the technique used, a spontaneous contrast can be obtained due to the heterogeneity of the tissues analyzed, so it is possible to study the organs, blood vessels and heart chambers without resorting to the injection of contrast .
Read detail about MRI in here.. Magnetic Resonance Imaging (MRI)
The examination is prescribed by a physician and performed in a radiology practice or institutional care (hospitals and clinics).
The MRI is painless and does not need to be fasting at the time of examination. No special preparation is required prior to the completion of the examination. However, it is necessary to remove all metal objects and jewelery before the exam. You need to know your history to the radiologist before the MRI so he can know if you do not submit a cons-indication to the achievement of this review: metallic foreign body in the eye, surgical metal in the skull, pacemaker which, due to the effect of the magnet may move during the examination.
Sometimes, specific contrast agents (gadolinium) is injected during the test. Ensure you have the relevant ordinances.
Make sure you bring the prescription order review, your Social Security card and another.
MRI plays a decisive role in the diagnosis of disorders of the pituitary secretion. This test is also useful for estimating the impact of a possible lesion of the pituitary gland on adjacent tissues (brain) to help the surgeon to identify before surgery and to monitor when the lesion was treated.
MRI has become the gold standard in this indication and the scanner is now realized that when there is an indication-cons MRI.
Allergy to contrast media used in MRI are very rare. MRI is cons-indicated in case of metallic foreign body in the eye, surgical metal in the skull or pacemaker. Because of the effect of the magnet, metallic material could move during the examination.
MRI can be performed in pregnant women, but it is nevertheless necessary to avoid injections of contrast medium in the early months of pregnancy and during lactation.
People who suffer from claustrophobia may poorly tolerate the examination. This is also the case for those who are very sensitive to noise. Ear plugs can be used during the exam.
The person is lying on a table that slides inside a tunnel of approximately 2 m long. It is not necessary to be asleep for an MRI. The test takes 20 to 30 minutes. The machine is quite noisy and are asked not to move and breathe quietly during the time of the examination.
Sometimes, a contrast medium is injected at the time of image acquisition to obtain more accurate images of the injuries or certain anatomical structures. A catheter is then introduced into a vein and the product is injected rapidly. It is possible to experience a heat at the time of injection. In persons with allergies to iodine, preventive treatment is required for 48 to 72 hours before the exam. When contrast material is injected, it is advisable to fast in the hours before the examination.
MRI images are available after the examination, but they must always be analyzed by a radiologist. It is possible that this analysis takes several hours or even days. The results are given in the form of a report to be transmitted to the prescriber to review images reproduced on paper plates, and possibly a CD-ROM which can be viewed on a computer equipped specific programs for reading radiology.