NMR and MRI Quiz

Select the correct proposition regarding the successive sequential steps of the NMR:

• Resonance-Polarization-Repetition

• Relaxation-Precession-Resonance

• Polarization-Resonance-Relaxation

• Resonance-Relaxation-Repetition

• Repetition-Polarization-Excitation

The magnetic field B0 used in MRI:

• has an intensity of the order of μTesla

• directs all the nuclei of the body in a specific way

• orients all magnetic moments in the same direction

• is produced by antennas/Coils

• is applied along the cranio-caudal axis of the patient.

The magnetic field B0 produces a precessional movement of nuclear magnetic moments with a Larmor frequency ν0. If we double the intensity of the B0 field, the frequency ν0 will be multiplied by:

• 0.25

• 0.5

• 2

• 4

• 8

A radio frequency wave:

• is an electromagnetic radiation

• acts on all atomic nuclei placed in a magnetic field B0.

• is an ionizing radiation.

• produces a phenomenon of polarization

• places the protons on two different energy levels.

The gyromagnetic ratio of hydrogen is 42.6 MHz / T. what is the frequency value that can cause proton resonance in a 3T field?

• 21.3 MHz

• 42.6 MHz

• 85.2 MHz

• 127.8 MHz

• 170.4 MHz

In the phenomenon of nuclear magnetic resonance, the relaxation:

• results in the return of the protons to the situation before excitation

• is accompanied by an emission of X photons

• is accompanied by an emission of Radio frequency waves

• gives rise to regrowth of transverse magnetization

• leads to a cancellation of the longitudinal magnetization

The time T1 measured for a given tissue is 1 second. After how long will the longitudinal magnetization reach 63% of its maximum equilibrium value?

• 0.001 s

• 0.01 s

• 0.1 s

• 1 s

• 10 s

Choose the correct answer(s) regarding the MRI signal:

• A tissue with a long T1 has a weak T1-weighted signal

• A strongly calcified area appears in hypointense in T1 and T2 weighting

• The air appears black because it contains few protons

• The fluids are hypointense in T2

• A tissue with a short T2 has a weak T2-weighted signal

What is (are) the correct answer (s) regarding MRI imaging?

• MRI makes it possible to obtain images in different section planes.

• MRI exposes patients to ionising radiations.

• The MRI acquisition time is a few seconds

• Contrast agents can be used

• MRI allows soft tissue to be seen with higher contrasts than with computed tomography.

Is this a T1 or T2 weighted image? Justify your answer