2.T2: Also known as spin relaxation, the process in which a nuclear spin system in a high-energy state transfers energy to the surrounding ring (lattice or solvent) and returns to a low-energy state by itself.
3. Magnetic vibration dwi refers to diffusion-weighted imaging of magnetic vibration.
4.SWI is magnetically sensitive weighted imaging, and its full English name is Susceptibilityweightedimaging. Significance: Magnetic susceptibility weighted imaging is very sensitive to display venous blood vessels, blood components, calcification and iron deposition. It is widely used in the diagnosis of various hemorrhagic diseases, venous vascular abnormalities, tumors and degenerative diseases and the quantitative analysis of iron content.
Extended data:
Medical use of magnetic vibration;
The most commonly used nucleus of magnetic vibration is hydrogen atom, that is, nuclear proton (1H), because it has the strongest signal and widely exists in human tissues. The factors influencing magnetic resonance imaging are: (a) proton density; Duration of deregulation; (c) Blood and cerebrospinal fluid flow; (d) paramagnetic materials; Protein.
The gray-scale characteristics of magnetic vibration images are that the stronger the magnetic vibration signal, the greater the brightness, the weaker the magnetic vibration signal and the smaller the brightness, ranging from white, gray to black.
The gray characteristics of MRI images of each tissue are as follows: adipose tissue and cancellous bone are white; Cerebrospinal cord and bone marrow are white and gray; Viscera and muscles are grayish white; Liquid, normal speed blood flow is black; Bone cortex, inflatable lung and inflatable lung are black.
Another characteristic of NMR vibration is that flowing liquid does not produce signals called flow effect or flow blank effect. So blood vessels are gray tubes, blood is black, and there is no signal. This makes it easy to separate blood vessels from soft tissues. Normal spinal cord is surrounded by cerebrospinal fluid (CSF), which is black with white dura mater and fat, making the spinal cord look like a white strong signal structure.