The phenomenon of magnetic resonance (MR) was discovered as early as 1945 by the Blok-led Stanford team and the MIT-led MIT team. However, until the 1960s, after the birth of spectrometers with high magnetic fields, high resolution, and Fourier transform techniques, the application of magnetic resonance in the field of biology had made substantial progress. The main magnet of the MRI system is used to generate a highly uniform and stable static magnetic field, which can be permanent, inductive, and superconducting magnets. The main magnet is generally made into a cylindrical or rectangular cavity, which can not only install the coil of the main magnet, but also can install X, Y, and Z-direction gradient magnetic field coils and a whole body of radio-frequency transmitting coils and receiving coils. The patient enters the patient bed among them. As the computer is the control center of the system, its computing power and stability are particularly important. ARBOR computer has been widely used in many kinds of medical equipment because of its powerful function, stable performance and strong adaptability to the environment, among which EmETXe-i9455 has been successfully applied to large-scale superconducting magnetic resonance imaging system.
In recent years, because magnetic resonance imaging has the advantages of high contrast, high resolution, no observable dead angle, and no side effects on the human body, it has attracted a large number of scientific research workers to invest in research, making magnetic resonance imaging technology has made great progress in the following areas:
1.Echoplannar maging (EPI), which greatly shortens the imaging time of MR, and gives high-resolution images within 100 to 200 ms (pixel width <1.5 mm=. Lower resolution image (pixel width) >3mm) Available in 50ms.
2. Magnetic resonance angiography (MRA) is superior to CT and X-ray angiography in that it does not require contrast media to obtain vascular imaging. There are magnetic resonance perfusion and permeation weighted imaging, which not only provides information on the morphology of human tissues and organs, but also provides functional information.
3. Magnetic resonance imaging intervention, with good tissue contrast, can accurately distinguish the interface of the lesion and determine the target; Sub-millimeter spatial resolution facilitates lesion location and intervention guidance; Multi-layer and three-dimensional spatial imaging allows comprehensive observation of important Anatomical structures; fast and ultra-fast imaging sequences allow for near-real-time observations of changes in physiological movements, interventional devices, and interventions.
4. Techniques to eliminate artifacts, such as spatial pre-saturation, gradient magnetic moments elimination, and rapid imaging, can effectively eliminate the body's physiological movements such as respiration, blood flow, cerebrospinal fluid pulsation, heart beat, gastrointestinal motility, etc. Resonance image artifacts.
The figure below is a block diagram of a universal magnetic resonance system:
The gradient generator generates a gradient current of a certain switch shape, which is amplified and then sent to the gradient coil by the drive circuit to generate a desired gradient magnetic field.
RF transmitters include frequency synthesizers, RF formation, amplification, and power amplifiers that generate the required RF pulse currents for transmission to the RF transmit coils.
The receiver consists of front-end, RF, band-pass filter, detector, low-frequency and A/D converters. The received magnetic resonance signal is amplified and processed into a digital signal that enters the computer.
The computer reconstructs the acquired data and sends the image data to the display for display. In addition, the computer is also responsible for controlling the operation of each part of the entire system, so that the actions of all parts of the imaging process are coordinated and the required high-quality images are produced.
In order to accelerate the research and popularization of magnetic resonance imaging technology, many developers have developed and produced many portable ultra-small magnetic resonance imaging instruments. ARBOR EmETXe-i9455 has been successfully used in ultra-small magnetic resonance imaging equipment because of its small size, high computing power, low power consumption, and stable performance. This type of equipment is mainly used in the examination of local lesions in hospitals and teaching or spectral studies in colleges and universities.