What does t 1 long t2 high flair signal mean in head magnetic resonance imaging?

T 1 and T2 time are the characteristics of tissues and cannot be changed, just like the types of tissues (such as muscle tissues and epithelial tissues). T 1 and T2 weighted magnetic resonance imaging are based on these characteristics of tissues. Specifically, this characteristic is defined as: T 1 is the time for the spin to recover to 63% vertically after the pulse is applied (flip angle = 90). (Why do you need to recover? When the flip angle = 90, all longitudinal large Mag are transformed into transition ...) .....

T 1 and T2 time of liquid are generally longer, which is also the reason why the CSF part is brighter when looking at brain images (T2 weighted). ...

T 1 and T2 of tissue can also be changed by adding contrast agent (such as gadolinium), which is the principle of enhanced MRI.

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