Because different positions produce different degrees of black and white, distinguishing various organs is conducive to the detection of corpses. The basic principle of nuclear magnetic resonance involves physical knowledge. The most abundant nucleus in human body is H 1, so this is also the choice of imaging, which provides the basis for successful examination. This substance is the most magnetic in the human body.
During inspection, the particles in the whole magnetic field are arranged in order. Generally, it can be divided into two types: low-energy level and large magnetic field are parallel and in the same direction, and high-energy level and large magnetic field are parallel and opposite. When the magnetic field is restored, these particles will return to their original state. Different tissues have different particle recovery rates because of different types. Because you can get different organizations.
Magnetic resonance imaging is to detect whether there are abnormal changes in various parts of the body, so as to judge whether there are tumors and the direction and speed of branch development. This kind of examination can find symptoms early, respond in time and deal with diseases. During treatment, recovery can also be detected and supervised. It is also a good means of examination for pregnant women.
Because it is necessary to change the magnetic field to observe the particle recovery, the whole inspection process is relatively long, about 30 minutes. This process needs the help of medical staff. In this process, just follow the instructions of the medical staff. After finishing, it usually takes several hours, and the doctor will give you the result. From the picture, the doctor can know whether there is any abnormality and make a summary. In this process, he just needs to wait quietly. Ordinary hospitals should advise testers to go home and wait for one to three days. Some hospitals can produce results in half a day. If you find your illness, you must seek medical advice in time and recover as soon as possible.
Extended data:
Matters needing attention in magnetic vibration
1. If there are magnets in the body, such as pacemakers, artificial valves, etc., and there are metal foreign bodies left beside important organs, this examination cannot be done. However, if there is an implant in the body that is confirmed by the surgeon as a non-magnetic object, magnetic resonance examination can be done.
2. Explain the following contents to technicians: whether there is a history of surgery; Whether there are any metal or magnetic substances implanted in the body, including metal contraceptive rings; Whether there are dentures, electronic ears and artificial eyes. ; Whether there is drug allergy; Whether there are metal foreign objects splashing into the body.
3. Don't wear underwear with metal substances. Patients with head and neck examination should wash their hair the day before the examination and do not use any hair care products.
4. Before the inspection, you need to take off all the clothes except underwear and put on special clothes for inspection in the magnetic vibration room. Remove metal products such as necklaces, earrings, watches and rings. Remove cosmetics, dentures, artificial eyes, glasses and other items from the face.
5. All medical history, examination data, all X-ray films, CT films and previous magnetic resonance films should be provided to the doctor before the examination.
6. Abdomen (liver, spleen, kidney, pancreas, biliary tract, ureter, etc. The examiner should fast for 4 hours before the exam and inject 654-2 before the exam.
7, magnetic resonance urography (MRU) examination before oral furosemide 20mg.
8, do magnetic vibration inspection should be prepared, don't be impatient, afraid, to listen to the doctor's guidance, patient cooperation.
References:
Baidu encyclopedia-magnetic vibration
Baidu encyclopedia-magnetic vibration test