What does nuclear magnetic resonance t 1 low signal t2 mean?

T 1 long means that the signal is low and the image is black.

T2 length means high signal and white image.

The low t2 signal of t 1 in NMR is a long T 1 short T2 signal, and the tissues where this signal appears are bone, fibrous tissue, calcification, hematoma, paramagnetic material, etc.

T 1 Preparation Through the direct interaction between hydrogen nuclei in water molecules and paramagnetic metal ions, T 1 is shortened, thus enhancing the signal and making the image brighter.

T2 preparation can shorten T2 by interfering with the inhomogeneity of external local magnetic environment, so that adjacent hydrogen protons can rapidly generate phase during relaxation, thus weakening the signal and darkening the image.

Extended data;

The spin quantum number of 1H is I= 1/2, so the spin quantum number m = 1/2, that is, the hydrogen nucleus should have two orientations in the external magnetic field. The two orientations of 1H represent two different energy levels, so the condition of 1H nuclear magnetic resonance is that the radiation frequency of electromagnetic waves must be equal to the precession frequency of 1H, that is, it conforms to the following formula.

Under the action of external magnetic field, 1H tends to align positively with the external magnetic field, so the number of nuclei in the low-energy state is more than that in the high-energy state. However, due to the small energy difference between the two energy levels, the former is only slightly superior to the latter.

Baidu encyclopedia-nuclear magnetic resonance principle