2. The pulse sequence below is used for imaging of breast tissue, which has the relaxation times for fibrous and adipose tissue types. a. If we want to null the signal from adipose tissue to gain sensitivity to other contrasts, what inversion time (TI) should be used? b. Draw the magnetization vector for each time indicated by lines a, b and c in the diagram for both fibrous and adipose signal. 90 RF 180 180 transmit T1fibrous = 869 ms TI= TE = 20ms T2 fibrous = 49 ms ladipose = 259 ms MRI signal T2 adipose = 84 ms MAA a b C Z b Z C ZA Z b ZA C Y Y Y Y y X X' x' Adipose Fibrous a b C a b C X4 X