Doctor, doctor, will my MRI examination have nuclear radiation and be harmful to the body? I am so scared, can I not do it? "Questions like this are often encountered in our work, and patients do not know what kind of examination MRI is. Outpatient doctors often do not explain too much due to the large number of patients, or inexperienced doctors may not have much understanding of MRI, resulting in so many questions when patients come for examination.
In fact, the nuclear magnetic resonance that we often use does not emit any radiation. Although its name includes a nucleus, it refers to an atomic nucleus and does not contain any ionizing radiation. It also has an English abbreviation, MRI. The working principle of nuclear magnetic resonance is mainly to use radio frequency pulses to excite and release energy, and these radio frequency pulses are mainly electromagnetic waves. Images are collected in magnetic resonance through electromagnetic waves, and the impact of these electromagnetic waves on the body can be basically ignored, so nuclear radiation does not exist in nuclear magnetic resonance. Patients do not need to worry about radiation and rejection when they need to undergo examinations, as it will not cause any harm to the human body or damage tissues to nuclear radiation. It is a very safe auxiliary examination.
So what do we know about nuclear magnetic resonance imaging (MRI), but in which situations do we need to undergo MRI examination? In fact, the indications for magnetic resonance imaging are quite broad, and it can be performed on almost all parts of the body. In terms of subdivision, there are several aspects: (1) Neurological disorders, such as cerebral infarction, brain tumors, inflammation, degenerative diseases, congenital malformations, trauma, etc. The nervous system is the earliest applied human system and has accumulated rich experience. The localization and qualitative diagnosis of lesions are accurate and timely, and early lesions can be detected. ⑵ The cardiovascular system can be used for the diagnosis of heart disease, cardiomyopathy, pericardial tumors, pericardial effusion, as well as wall attached thrombosis and intimal detachment. ⑶ Chest lesions, such as tumors, lymph nodes, and pleural lesions in the mediastinum, can indicate the relationship between lung masses and larger trachea and blood vessels. ⑷ Diagnosis and differential diagnosis of abdominal organs, such as liver cancer, hepatic hemangioma, and hepatic cysts, as well as the diagnosis and differential diagnosis of intra-abdominal masses, especially retroperitoneal lesions. (5) Pelvic organs, such as uterine fibroids, other uterine tumors, ovarian tumors, qualitative localization of pelvic masses, tumors in the rectum, prostate, and bladder, etc. (6) Bone and joint diseases, such as intraosseous infections, tumors, and injuries, have significant diagnostic value for small changes such as bone contusions. Joint cartilage, ligaments, meniscus, synovium, synovial fluid sac, and bone marrow lesions have high diagnostic value. ⑺ Systemic soft tissue lesions, whether originating from tumors, infections, degenerative lesions of nerves, blood vessels, lymphatic vessels, muscles, connective tissues, etc., can be accurately located and qualitatively diagnosed.
After understanding the principles and indications of magnetic resonance imaging, can we go to a doctor to get a check-up? The answer is not. In fact, there are many pre examination precautions for our MRI, and there are situations where it cannot be examined, namely absolute contraindications, such as patients with pacemakers, nerve stimulators, aneurysm clips, metal foreign bodies in the eyeball, cochlear implants, insulin pumps in the body, and patients with febrile seizures. Once these patients enter the MRI room for examination, they are likely to bring life-threatening situations and cannot be examined under any circumstances.
When there are vascular clips, contraceptive rings, metal internal fixation plates, prosthetic joints, intravascular stents, artificial blood vessels, filters, coil splitters, artificial heart valves or other implants in the body, if the product manual and relevant evidence can be presented to indicate that the implant is non ferromagnetic or weakly ferromagnetic, it can also be examined after comprehensive evaluation. This is the relative contraindication I want to talk about. In addition, critically ill patients, uncooperative children, deaf and mute individuals, or patients with claustrophobia are also relatively contraindicated.
After discussing the contraindications, patients and their families entering the examination room are prohibited from carrying any metal items, such as mobile phones, watches, metal necklaces, magnetic cards, coins, keys, lighters, metal buttons, hearing aids, etc. False teeth, artificial eyes, prosthetics, hairpins, glasses, ointments, magnetic therapy underwear, corsets, and bras must also be removed. In addition, certain medical equipment is also prohibited from entering the examination room, such as stretchers, wheelchairs, ICU beds, oxygen cylinders, monitors, infusion pumps, ventilators, forceps, stethoscopes, scissors, etc.
After completing the above procedures, we can proceed with the examination with peace of mind. Generally speaking, the examination time for MRI is longer than other imaging examinations, ranging from a few minutes to several tens of minutes. During the examination, there is a lot of indoor noise, which is caused by the switching of the magnetic field gradient system during the operation of the MRI. Generally, headphones, earplugs, and other items are equipped to provide patients with a comfortable state for the examination. In addition, a very small number of patients may feel a slight fever during the examination process, which is actually due to the gradual increase in skin surface temperature caused by the action of wireless radio frequency pulses during the operation of magnetic resonance imaging. However, this is also a normal phenomenon and there is no need to worry.
After the MRI examination is completed, it is time to wait for the results, which usually include X-rays and paper diagnostic reports. Due to the different number of patients and specific situations in each hospital, the waiting time for the results also varies. Some checks can be taken within an hour, while others require results the next day. So this requires understanding and patience from patients and their families.