Consider a constant magnetic fieldis applied to an object. The gyromagnetic ratio of the...

Consider a constant magnetic fieldis applied to an object. The gyromagnetic ratio of the object isSuppose the following RF pulse is applied

(a)FindWrite down an equation to calculate the tip angle.

(b) Assumeis long enough so thatcould be approximated as

What is the spectrum of? Sketch it.

Suppose a slice selection gradient is applied in z direction while is applied and

(c) Where is this slice centered? What is the slice thickness?

(d) If you want to select another slice adjacent to the current slice (moving in the +z direction) with the same slice thickness, how should you change the RF pulse? Assumestays the same.

e) Right after the RF pulse in (d), what is the maximum phase difference of the spins inside the current slice? How does one rephase the spins?

(f) Suppose you want to sampleusing a sampling trajectory that starts as shown in Figure P13.10. Assume thatSketch a pulse sequence to achieve this part of the trajectory. Indicate the acquired signal, the readout gradient, the

phase-encoding gradient, and the slice selection gradient.