3. MRI pulses can be applied at either 90 or 180 degree angles. Determine the relative decay for an MRI image using 11/2 (90) and TT (180) rotations using the below equation and constants in white matter and a malignant tumor at the time t=250 ms. Which angle provides more contrast between the two tissue types? , For = = 1- exp 2' M M For = = 1-2 * exp M T1 = 380 ms for white matter, 800 ms for tumor. of P