The canonical name of nuclear magnetic resonance should be called magnetic resonance, magnetic resonance belongs to the category of medical imaging, magnetic resonance is the use of hydrogen nuclei in the human body in the magnetic resonance instrument in the strong magnetic field space to produce resonance, and in this process the release of energy information, through the high-energy electronic computer system to collect these signals, and then through the digital reconstruction technology into magnetic resonance images, provided for clinical use in the diagnosis of diseases.
In this complex process, the resonance of hydrogen nuclei under the action of external magnetic fields is formed after being processed by electronic computers to form an image for diagnosis, so some people also call it nuclear magnetic resonance. #夏方养生指南 #
What are the advantages of NMR technology?
1. Safety inspection without damage: no radiation damage, the examination is safer, especially suitable for children with growth and development and female patients during childbearing.
2. Any azimuth tomography: MR scan can obtain transverse, coronary, sagittal or any angle of the image under the condition that the patient's position is unchanged, which is obviously better than CT in showing the lesion range, the relationship between the lesion and the surrounding tissues, and the three-dimensional observation of the lesion.
3. Boneless artifacts: streak-like artifacts can appear at the edges of the bone such as the base of the skull during CT examination, which seriously affects the diagnosis of posterior cranial convex lesions, MRI has no bone artifacts, and the diagnosis of lesions in the brainstem and cerebellum is significantly better than CT.
4. Early detection of lesions: MRI examination is conducive to the early detection of lesions, such as early cerebral infarction, early bone metastases and early aseptic necrosis of the femoral head.
5. With high contrast: especially the contrast of soft tissues is significantly higher than that of CT, which can clearly and realistically display anatomical structures, observe the size, shape and location of organs very well, can show blood vessels, gallbladders and ureters, nerve fibers and other structures, and is better than CT for lesions such as cranial brain, spine and spinal cord, joints, and soft tissues.
Why not recommend "MRI"? The doctor tells the truth
Case 1:
In 2001, an earlier accident in the United States was exactly two decades old.
In July 2001, a magnetic resonance accident occurred at Westchester Medical Center in upstate New York, killing a 6-year-old boy. The boy, Michael Colombini, was underwent a magnetic resonance imaging examination to observe the prognosis after surgery to remove a benign brain tumor.
At the time of the accident, the boy had been injected with a sedative, entered the magnetic resonance device, and when the 10-ton magnet was turned on, a powerful magnetic field sucked a metal oxygen tank the size of a fire extinguisher from the other end of the examination room, hitting the boy in the head.
Two days later, the boy died of blunt force injuries, skull fractures and brain contusions. At that time, the magnetic force of the magnet was about 30,000 times that of the Earth's magnetic field.
Case 2:
In a mobile MRI truck at Sunderby Hospital in Sweden, a patient was reportedly lying on a test bed ready for an MRI scan, and before entering, the nurses conducted a strict examination of him and demanded that the jewelry, watches and other prohibited items worn on his body be removed.
The patient had put on the earplugs and began to examine, but suddenly heard a loud noise, and then heard someone crying, and the mouth was hit by a hand.
He was stunned by what he saw: a nurse stuck in a machine above his head.
He managed to crawl out of the MRI hole and saw the nurse's neck tightening tighter and tighter by the vest she was wearing, in danger of suffocation at any moment, and the vest was sucked tightly into the MRI hole.
Two security guards came over and tried to pull the nurse out, but it didn't work. Finally, the security guard cut open the vest before the nurse was rescued, and because of the serious injuries, the nurse was admitted to the ICU for treatment.
Even if the regulations are strictly followed, the following problems are faced when performing MRI:
1. There are limitations
MRI will be more accurate for soft tissues, such as the rectum, uterus, joints, muscles and other parts, but for the lungs, liver, prostate, pancreas and other organs. The test results are not as accurate as CT or X-rays, especially for gastrointestinal disorders, and the MRI is not as clear as the gastroscopy.
2. The detection time is long
Because nuclear magnetic resonance (NMR) needs to run a magnetic field during the inspection, it is done by splitting the part, so it is more complex and the time required for the inspection will become longer.
The time of an examination is about 30 minutes, if the patient does not cooperate during the examination, other conditions occur, the examination time will be extended, if it is an acute disease, it is necessary to understand the situation in a short period of time, and doing MRI will delay the condition, so that the patient cannot get timely treatment.
3. Metal objects cannot be worn
Before doing MRI, the doctor will ask the metal in the body to be removed, because the metal will be adsorbed by the instrument during the magnetic field scan, resulting in damage to the instrument.
It can even create an electric field in the patient's body, causing heart excitement, ventricular tremor, and some patients will have an increase in body temperature, especially for patients with metal stents and cardiac stents, this test can hurt them and cause metal displacement.
4, the price is high
Since MRI is a part-by-part scan, it not only takes a long time, but also costs high, and the cost of different parts is different. If a full-body examination is required, it will be necessary to pay the fee multiple times, and the amount spent will bring medical burden to the average family.
Conclusion:
MRI requirements for doctors and patients are very high, the operation process is also unusually troublesome, because of this, unless the last resort, doctors will not recommend patients to do MRI examination, which is also from the patient's position to consider the problem.