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Unit 1 quiz
Unit 1 quiz
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1
What does the mass number of an atom represent?
Number of electrons
Number of protons
Sum of protons and neutrons
Number of neutrons
2
What does the term "alignment" refer to in MRI?
The number of protons in the nucleus
The speed of precession
The time it takes for a pulse sequence
The orientation of magnetic moments relative to Bo
3
What are ions?
Molecules in a chemical bond
Atoms with surplus of neutrons
Atoms with an excess or excess or deficit of electrons
Particles in the atomic nucleus
4
What does the atomic number of an element represent?
Number of electrons
Sum of protons im the nucleus
Sum of neutrons and protons
Number of neutrons
5
What is the primary purpose of the repetition time (TR)?
Control T2 relaxation
Control T1 relaxation
Adjust magnetic strength
Affect flip angle
6
The NMV moves into the transverse plane due to:
RF pulse excitation
Precession
T2 decay
T1 recovery
7
Which of the following nuclei is NOT MR active?
Phosphorus-13
Hydrogen-1
Helium-4
Carbon-13
8
The process of returning to thermal equilibrium is known as____.
Relaxation
Excitation
Precession
Diffusion
9
Which of the following is responsible for the MR signal production?
Magnetic resonance effect
Coherent transverse magnetization
T2 Decay
Excitation
10
What type of electromagnetic radiation is used in MRI to excite hydrogen nuclei?
Radiofrequency (RF)
High energy x-rays
Visible light
Gamma rays
11
Which theory explains MRI using mass, spins, and angular momentum?
Classical theory
Quantum theory
Electromagnetic theory
Newtonian theory
12
What is the term used to describe the spin of MRI-active nuclei?
Larmor frequency
Precession
Magnetic moment
Angular momentum
13
What is the gyromagnetic ratio?
The speed of precession 1.0T
The relationship between protons and neutrons
The time required for longitudinal relaxation
The frequency of RF pulses at 1.0T
14
Which of the following refers to atoms with an odd mass number?
Nucleons
Elections
Ions
Isotopes
15
What does the echo time (TE) control?
Flip angle
Proton density
T2 contrast
T1 contrast
16
The MR signal is detected in which plane?
Coronal
Transverse
Saggital
Longitudinal
17
The phenomenon in which hydrogen nuclei wobble when placed in a magnetic field is called:
Excitation
Relaxation
Resonance
Precession
18
The process of energy absorption by hydrogen nuclei during an RF pulse is called:
Relaxation
Decay
Resonance
Precession
19
Precessional frequency is measured in Tesla.
True
False
20
The principle that explains how a changing magnetic field induces an electromotive force is called______.
Faraday's Law
Ohm's Law
Ampere's Law
Lenz's Law
21
Which term describes the random motion of molecules contributing to MRI contrast?
Brownian motion
Flip angle
Magnetization
Precession
22
What does ionization refer to?
The formation of atoms
The spinning of electrons
The removal of electrons from an atom
The process of adding electrons
23
The hydrogen nucleus used in MRI is called?
Carbon-13
Protium
Tritium
Deuterium
24
The stronger the external magnetic field (Bo), the:
Lower the resonance
Higher the processional frequency
More random the alignment
Lower the NMC
25
What is the gyromagnetic ratio of hydrogen at 1 Tesla?
84.00 MHz
21.28 MHz
63.86 MHz
42.58 MHz
26
What is Faraday's Law?
It describes the connection of a magnetic field and an electric field in mo
It states the relationship between mass and velocity
It describes the relationship between voltage and current
It defines the precessional frequency of an element?
27
What is the term for hydrogen nuclei aligning with Bo?
Longitudinal decay
Parallel alignment
RF excitation
Anti-parallel alignment
28
What are protons?
Particles that spin around the nucleus
Positively charged elements of the atomic nucleus
Electrons
Neutrally charged elements of the atomic nucleus
29
The _____ field is responsible for the resonance in MRI.
Bo
Radiofrequency
B1
Gradient
30
What is "free induction decay" (FID)?
The alignment of magnetic moments
The energy required for spin excitation
The time between RF pulses
The loss of signal die to relaxation
31
The external magnetic field (Bo) causes nuclei to align either:
In a circular motion
In random directions
Parallel or perpendicular
Parallel of antiparallel
32
What is the most abundant atom in the human body?
Carbon
Nitrogen
Hydrogen
Oxygen
33
The most commonly use isotope in MRI is ______.
Oxygen
Helium
Nitrogen
Protium
34
What is the longitudinal plane in MRI?
Axis perpendicular to Bo
Axis parallel to Bo
The region where excitation pulses occur
The path of precession
35
Which particles spin around the nucleus of an atom?
Neutrons
Electrons
Nucleons
Protons
36
The net magnetization vector (NMV) moves out of alignment due to:
Bo Field
T1 recovery
Free induction decay
RF Excitation
37
The _____ time (TE) determines how much T2 relaxation has occurred.
Echo
Pulse
Repetition
Decay
38
The NMV is the net magnetic vector resulting from excess spin-up nuclei.
False
True
39
The Larmor Equation is given by:
Wo = Bo X Y
Y= Bo X Wo
T1= T2 X Bo
Bo=Wo X Y
40
What does the term "flip angle" refer to in MRI?
The degree of signal decay
The speed of precession
The angle at which the NMV is flipped relative to Bo
The rate of change of phase
41
The free indiction decay (FID) signal occurs after the RF pulse is:
Interrupted
Turned on
Increased in frequency
Turned off
42
What is the unit of precessional frequency?
Tesla
Newton
Gauss
Megahertz (MHz)
43
What is the primary magnetic field of the MRI scanner denoted as?
Magnetic Flux
Bo
B1
Tesla field
44
What does the Boltzmann equation predict?
The net magnetic vector
The frequency of RF pulses
The number of spins in each energy level
The alignment of protons
45
The primary factor that determines the flip angle is:
Amplitude and duration of RF pulse
Precession frequency
Magnetic field strength
Phase coherence
