Brain hemorrhage MRI performance on MRI is more complex, but also dynamic evolution, each phase of brain hemorrhage in MRI performance is different, each phase performance is as follows: 1, the hyperacute phase refers to the blood time less than 6 hours, leakage of blood has not yet coagulated, showing blood long T1, long T2 signal, diffusion image is high signal; 2, the acute phase refers to 2 days after the blood, red blood cell cell membrane remains intact, intracellular oxygenated hemoglobin release 2. 2 days after the acute phase, the red blood cell membrane remains intact and the intracellular oxygenated hemoglobin is released into deoxyhemoglobin, which is paramagnetic and can shorten the T2 duration with a slightly higher low mixed signal and high diffusion signal; 3. 3 days after the subacute phase, the red blood cell membrane remains intact and intracellular orthoferric hemoglobin appears with strong paramagnetism, which shortens the T1 value of the hematoma. Therefore, the hematoma appears high signal from the periphery to the center in T1, low signal in T2, and high signal in the periphery and low signal in the center in diffusion images; 4. In the middle subacute stage, generally speaking, 6-10 days after the hematoma, the erythrocyte cell membrane begins to rupture, and ortho-iron hemoglobin leaks out to the outside of the cell, and the T2 image develops from the periphery to the center in high direction; 5. In the late subacute stage, generally speaking, 10-21 days after the hematoma, the erythrocytes are completely disintegrated The hematoma is mainly dominated by ortho-hemoglobin, and macrophages in the periphery of the hematoma swallow hemoglobin to form iron-containing heme, which has obvious paramagnetic properties and causes magnetic field inhomogeneity. Therefore, hematoma T1 and T2 show significant high signal in this stage, and a linear low signal ring is seen around T2. In the chronic phase, usually after 3 weeks to several months of bleeding, the hematoma gradually absorbs and liquefies, evolving into a liquefied foci with macrophages around the hematoma, with obvious deposits of iron-containing heme, so it shows a low-signal ring on T2.