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Question 1

Which of the following nuclei cannot be used for MRI?

17O $^{17}O$

19F $^{19}F$

12C $^{12}C$

23Na $^{23}Na$

Question 2

When protons are placed in a strong external magnetic field, their magnetic moments rotate around the axis of the magnetic field (wobbling). What is this process called?

Spin excess

Precession

Gyroscope

Spin

Question 3

The gyromagnetic ratio of

31P $^{31}P$ is known as

108.291×106rad⋅s−1⋅T−1 $108.291 \times {10}^{6} rad \cdot {s}^{-1} \cdot {T}^{-1}$ or

17.235×106Hz⋅T−1 $17.235 \times {10}^{6} Hz \cdot {T}^{-1}$ . By what factor are the two units related?

2π $2\pi$

4π $4\pi$

3π $3\pi$

π $\pi$

Question 4

When protons are placed in a steady magnetic field

B0 $B_{0}$ , in which axis does the net magnetization

(M→) $(\vec{𝑴})$ exist?

There is no net magnetization.

x-axis

z-axis

y-axis

Question 5

What is the gyromagnetic ratio of

1H $^{1}H$ in 1 T MRI?

127.74 MHz

42.58 MHz

58.42 MHz

48.25 MHz

Question 6

Clinical MRI scanners typically operate at magnetic field strength of 3T. What is the Larmor frequency of

1H $^{1}H$ at 3T?

$\quad$ (Gyromagnetic Ratio of

1H $^{1}H$ is

267.513×106rad⋅s−1⋅T−1 $267.513 \times {10}^{6} rad \cdot {s}^{-1} \cdot {T}^{-1}$ )

401.27×106Hz $401.27 \times {10}^{6} Hz$

127.74×106Hz $127.74 \times {10}^{6} Hz$

63.87×106Hz $63.87 \times {10}^{6} Hz$

802.54×106Hz $802.54 \times {10}^{6} Hz$

Question 7

The following picture depicts magnetic resonance, the tipping of initial magnetization $(M_{0})$ vector with a flip angle $(\alpha)$ . Which of the following is a correct expression for the resulting transverse magnetization $(M_{xy})$ ?

M0⋅tanα $M_{0} \cdot tan \, \alpha$

M0⋅cosα $M_{0} \cdot cos \, \alpha$

M0 $M_{0}$

M0⋅sinα $M_{0} \cdot sin \, \alpha$

Question 8

M0⋅cosα $M_{0} \cdot cos \, \alpha$

M0⋅tanα $M_{0} \cdot tan \, \alpha$

M0 $M_{0}$

M0⋅sinα $M_{0} \cdot sin \, \alpha$

Question 9

Which of the following statements is correct regarding magnetic resonance phenomenon (as shown in the picture)?

The excess spins pick up energy and move from parallel to anti-parallel state.

In rotating reference frame, the net magnetization vector follows a spiral trajectory.

Only longitudinal magnetization can be detected and used for imaging.

The protons start to precess out-of-phase, leading to disappearance of net magnetization.

Question 10

Which of the following refer to the relaxation mechanism in the transverse direction?

(Choose all that apply) $\textbf{(Choose all that apply)}$

T2 ${T_{2}}$ relaxation

T1 ${T_{1}}$ relaxation

Spin-spin relaxation

Spin-lattice relaxation

Question 11

Which of the following refer to the relaxation mechanism in the longitudinal direction?

(Choose all that apply) $\textbf{(Choose all that apply)}$

T1 ${T_{1}}$ relaxation

Spin-spin relaxation

Spin-lattice relaxation

T2 ${T_{2}}$ relaxation

Question 12

The normal human brain at 3 T has tissue

T1 ${T_{1}}$ and

T2 ${T_{2}}$ times. Which of the following shows the correct tissue-longitudinal magnetization pair after

30∘ $30^{\circ}$ flip angle and 400 ms time delay if the initial magnetization

M0=1 $M_{0}=1$ ?

$\quad$ (At 3 T,

T1 ${T_{1}}$ and

T2 ${T_{2}}$ values of

gray matter $\textbf{gray matter}$ are 1331ms and 80ms respectively.

T1 ${T_{1}}$ and

T2 ${T_{2}}$ values of

white matter $\textbf{white matter}$ are 832ms and 110ms)

Gray Matter,

Mz=0.90 $M_{z} = 0.90$

White Matter,

Mz=0.74 $M_{z} = 0.74$

Gray Matter,

Mz=0.55 $M_{z} = 0.55$

White Matter,

Mz=0.36 $M_{z} = 0.36$

Question 13

The normal human brain at 3 T has tissue

T1 ${T_{1}}$ and

T2 ${T_{2}}$ times. Which of the following shows the correct tissue-transverse magnetization pair after

60∘ $60^{\circ}$ flip angle and 50 ms time delay if the initial magnetization

M0=1 $M_{0}=1$ ?

$\quad$ (At 3 T,

T1 ${T_{1}}$ and

T2 ${T_{2}}$ values of

gray matter $\textbf{gray matter}$ are 1331ms and 80ms respectively.

T1 ${T_{1}}$ and

T2 ${T_{2}}$ values of

white matter $\textbf{white matter}$ are 832ms and 110ms)

White Matter,

Mz=0.74 $M_{z} = 0.74$

Gray Matter,

Mz=0.67 $M_{z} = 0.67$

Gray Matter,

Mz=0.36 $M_{z} = 0.36$

White Matter,

Mz=0.55 $M_{z} = 0.55$

Question 14

Which statement is not true?

The energy in the transmission RF coil should be applied parallel to B0.

The net transverse magnetization does not rotate when represented in the rotating reference frame.

The free induction decay (FID) signal is maximized when the netmagnetization is excited with a

90∘ $90^{\circ}$ RF pulse.

The receiver RF coil can detect signals from the transversemagnetization but not from the longitudinal magnetization.

Question 15

Relaxation due to

T2 $T_{2}$ is a reversible process.

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