Which is magnetic resonance and how it works
Magnetic resonance (IRM) is a diagnostic test used in medicine to obtain images inside our body. It is also known as nuclear magnetic resonance, and is based on an exploratory technique that creates very detailed images of human body tissues.
It uses a powerful magnetic field and radio waves to generate reliable images of body parts that cannot be seen in detail with other procedures such as: X -rays, computerized or ultrasound tomographies. For example, doctors can get images that allow you to see within the joints, cartilage, ligaments, muscles and tendons, making it a very useful tool to detect sports injuries.
This technology is widely used to sculpt the internal structures of the body, obtaining very detailed images, in two and three dimensions, and from any perspective. This non -invasive procedure allows to diagnose a variety of disorders, such as strokes, tumors, aneurysms, spinal cord injuries, tumors, heart problems, among many others.
It is also used in the investigation of brain structures and the specific function of each of its parts. One of the main advantages of this technique is that the patient is not exposed to radiation, compared to other procedures (such as computerized tomographies and radiographs) that could be harmful to some extent.
An NMR unit is composed of a huge circular tube surrounded by a cylindrical magnet. The patient should be lying on a stretcher that is sliding inside the magnet. Within the unit a specific part of the body can be scanned, generating a great magnetic field around the person, along with the magnetic waves that will be directed to the body.
During this stage the patient is not able to feel the magnetic field or radio waves, so the procedure itself is painless. However, during the procedure you can hear strong noises and blows generated by the system itself. This often forces some susceptible people, to use headphones with relaxing music that isolates them from outdoor environment, and making the most pleasant diagnosis.
As the case may be, some patients may receive a contrast solution during exploration, which is applied intravenously, this helps to visualize more precisely the integrity of blood vessels and some areas of the brain.
In cases where people suffer from claustrophobia, they are sedated with medication to relax them during exploration, because it is important to stay as still as possible to achieve clear images, since some abrupt movement can blur the images.
The exploration of the machine lasts between 30 to 60 minutes, on average, depending on the part of the body to explore. Obtaining results in images that are then evaluated by medical specialists, to make an accurate diagnosis of what is wrong.
Its operation.
The human body is mainly composed of water, reaching 70% in total of the corporeal mass. Water molecules (H2O) contain hydrogen protons in their nucleus, which are aligned when they enter a magnetic field. The NMR unit creates a very strong magnetic field (approximately 0.2 to 3 teslas, 1000 times more powerful than a common fridge magnet). These electromagnetic waves make these hydrogen atoms return to their usual alignment, without causing any chemical change in tissues.
When hydrogen atoms begin to take their initial alignment, a process called ‘precession’ begins. This produces different energy emissions that vary depending on the type of tissue is being explored. The NMR captures these energy variations, and creates based on the information obtained, different images of the interior of the body.
The protons return to their state of alignment in different speeds, depending on the type of body tissue, so the scanner can distinguish between several different types. The scanner can be adjusted depending on the type of tissue to be studied, through additional magnetic fields, obtaining three -dimensional images that can be seen from different angles.
A computational unit is responsible for evaluating and analyzing the different signals obtained by emissioning these radio waves on the body, generating a series of very precise images of each part of our body.
Functional magnetic resonance
Magnetic resonance is not only used to create images inside our body, it is widely used in the functional study of the human brain. Through these equipment you can see brain structures to determine which parts of our brain are handling critical functions, others, can measure the changes in blood flow in different parts of the brain.
Functional NMR is able to assess the damage caused by a cerebrovascular lesion, including Alzheimer’s. Becoming a revolutionary tool within neuroscience.
Benefits and risks
Like any medical procedure, the advantages and risks are intrinsically united, depending on many external and internal factors derived from the correct clinical evaluation and the appropriate procedures. Within these advantages and disadvantages we can cite the following:
Benefits:
MRI is a non -invasive exploration technique that does not imply exposure to ionizing radiation.
The RM images of the structures of the soft tissues of the body – such as the heart, liver and many other organs – have greater sensitivity in some cases to identify and characterize the diseases with precision that other methods of diagnosis by image. The details that are seen in the NMR make this method a valuable tool for early detection and evaluation of many central lesions and tumors.
It has been proven that NMR is a valuable tool for the diagnosis of a wide range of pathologies, including cancer, heart and vascular diseases, and muscle and bone anomalies.
MRI makes it possible to discover abnormalities that can be hidden from bones with other exploration methods.
MRI allows doctors to evaluate the biliary system in a non -invasive way and without contrast injection.
The contrast material used in NMR exams is less likely to produce an allergic reaction than iodine -based materials, used for conventional X -rays and TC explorations.
The NMR provides a non -invasive alternative to X -rays, angiography and TC to diagnose heart problems and blood vessels.
Risks:
MRI exams almost does not involve risks in the average patient if appropriate safety guidelines are followed.
If sedation has been used, there may be risks of excess sedation. However, the technologist or nurse will control their vital signs to minimize irrigation.
While the powerful magnetic field is not detrimental in itself, the implantable medical devices that contain metals can work badly or cause problems during the NMR examination.
Nephrogen systemic fibrosis is currently a recognized but rare complication of the MRI, which is believed to be caused by the injection of high doses of the contrast material based on gadolinium in patients with severe renal dysfunction. The careful evaluation of * * the kidneys before considering a contrast injection, minimizes the risk of this complication that is very rare.
There is a slight risk of allergic reactions when injecting the contrast material. These reactions are usually benign and easy to control through medication. If you experience allergic symptoms, a radiologist or other doctor will be available for immediate help.
Manufacturers of the intravenous contrast medium indicate that mothers should not breastfeed their babies 24-48 hours after mothers receive contrast medium. However, both the American College of Radiology (ACR) and the European Urogenital Radiology Society say that the available data suggests that there is no risk of continuing to breastfeed after receiving intravenous contrast. For more details, see the ACR manual on contrast media and its references.
In addition to the foregoing, it is important. For this reason, NMR technology is being used more frequently in fetus evaluation during pregnancy, obtaining optimal results without adverse effects.
However, the prediction is not exempt from risks, so experts in the field do not recommend their use in the early stages of pregnancy.
Likewise, because magnetic resonance uses powerful magnets for its operation, any type of strange metal, metal implants, such as pacemaker, artificial joints, artificial heart valves, cochlear implants and rods and screws implanted in our body, could cause theseThey heat or displace through the magnetic field.
In fact, many patients who had pacemaker and underwent scanners with magnetic resonance have died due to the malfunction of the vascular apparatus. So it is advisable to obtain all the critical information available before submitting to any scanning procedure through the NMR.
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