1, magnetic *** vibration MRI is also known as magnetic *** vibration imaging, the full name of the English language is: Magnetic Resonance Imaging. significance: nuclear magnetic *** vibration is a physical phenomenon, as a means of analysis is widely used in the field of physics, chemistry biology, etc., and it will be used in 1973 for the medical clinical testing. In order to avoid confusion with radiography in nuclear medicine, it is referred to as magnetic *** vibration imaging (MR).
Technical features are: magnetic **** vibration imaging is a kind of tomography, it uses the magnetic **** vibration phenomenon from the human body to obtain electromagnetic signals, and reconstruct the human body information.
2, magnetic *** vibration MRA is magnetic *** vibration angiography, the full name of the English is: Magnetic Resonance Angiography, meaning: magnetic *** vibration angiography, magnetic *** vibration angiography can be carried out, that is, to show the blood vessels, can be found in the parts of the blood vessels stenosis and occlusion.
Technical features: based on the saturation effect, inflow enhancement effect, flow dephasing effect. MRA is a pre-saturated strip placed at the head end of a 3D lamina block to saturate the venous blood flow, and the reverse flow of arterial blood enters the 3D lamina block, which is not saturated to produce an MR signal. During scanning, a thicker volume is divided into multiple thin excitation layers, reducing the thickness of the excitation volume to minimize the inflow saturation effect.
3. SWI is magnetic susceptibility weighted imaging, the full English name is: Susceptibility weighted imaging. Meaning: Magnetic susceptibility weighted imaging is very sensitive to the display of venous vessels, blood components, calcification, iron deposition, etc. It has been widely used in various hemorrhagic diseases. It has been widely used in the diagnosis of various hemorrhagic lesions, abnormal venous vascular lesions, tumors and degenerative diseases, and the quantitative analysis of iron content.
Technical features: The SWI instruction is used to generate a software interrupt so that the user program can call the operating system's system routines. The operating system provides corresponding system services in the exception handler of the SWI. The 24-bit immediate number in the instruction specifies the type of system routine called by the user program, and the related parameters are passed through the general-purpose registers.
The magnetic **** vibration of 0.5 and 3.0 represents the field strength of the magnetic **** vibration scanner, is the main performance index of the machine. 3.0T magnetic **** vibration is mainly used in hospitals, scientific research, to carry out research on the subject, etc., generally 0.35T magnetic **** vibration with the magnet is a normal conductive magnet. These values are used to reflect the size of the magnetic field strength generated by the magnetic *** vibration, the larger the value, the greater the magnetic field strength, the clearer the image produced, the shorter the scanning time will be.
Expanded InformationMedical Uses of Magnetic **** Vibration:
The most commonly used nucleus for magnetic **** vibration is the hydrogen nucleus proton (1H), because it has the strongest signal and is also widely available in human tissue. Factors affecting magnetic **** vibration imaging include (a) the density of the proton, (b) the length of the relaxation time, (c) the flow of blood and cerebrospinal fluid, (d) paramagnetic substances (e) proteins.
The gray scale of a magnetic **** vibration image is characterized by greater brightness the stronger the signal of the magnetic **** vibration, and less brightness when the signal of the magnetic **** vibration is weak, ranging from white, to gray, to black.
Various tissue magnetic *** vibration image gray scale characteristics are as follows: adipose tissue, cancellous bone is white; cerebrospinal cord, bone marrow is white-gray; viscera, muscle is gray-white; liquid, normal rate of flow of blood is black; bone cortex, gas, air-containing lungs is black.
Nuclear magnetic **** vibration of another feature is the flow of liquid does not produce a signal called the flow effect or flow blanking effect. Thus blood vessels are grayish-white tubular structures, while blood is signal-free black. This makes blood vessels easy to separate from soft tissue. The normal spinal cord is surrounded by cerebrospinal fluid, which is black, and has a white dura that is lined with fat so that the spinal cord shows up as a white, strongly signaling structure.