With the exception of hydrogen, all matter is composed of three components. They are
Electrons, Photons, Protons
Electrons, Neutrons, Photons
Protons, Neutrons, Photons
Neutrons, Electrons, Protons
The negatively charged component of an atom is called the
Electron
Proton
Negatron
Neutron
The positively charged component of an atom is called the
Positron
The neutral component of an atom is called the
Photon
The nucleus of the hydrogen atom is made up of one
Materials reach their highest magnetic potential when their atoms are grouped in areas known as
Regions
Fields
Fringes
Domains
Material that is weakly attracted to a magnetic field is said to be
Electromagnetic
Paramagnetic
Ferromagnetic
Diamagnetic
Material that is strongly attracted to a magnetic field is said to be
Material that is slightly repelled from a magnetic field is said to be
Resistive
Three types offerromagnetic material are
Copper, Titanium, Aluminum
Iron, Cobalt, Nickel
Bronze, Niobium, Tin
None of the above
To exist, magnets must have two poles, therefore they are commonly called
Vectors
Dipoles
Axis
A and C
The lines that represent the field of a magnet are known as
Flux lines
Intensity lines
Induction lines
Faraday lines
The strength of a magnet is measured by its
Signal intensity
Induction ability
Flux density
The strength of an MRI magnet is most commonly represented by a unit of measurement called
Amps
Kilogauss
Tesla
Ohms
10,000 gauss is equal to
1.0 amp
1.0 ohm
1.0 tesla
10 tesla
15,000 gauss is equal to
1.5 amps
1.5 ohms
1.5 tesla
15 tesla
The law that is used in MRI to describe how a magnetic field is induced by flowing current is known as
Damadian's Law
Murphy's Law
Newton's Law
Faraday's Law
Which of the following is an advantage of a permanent magnet MRI system?
Very heavy
Low operating costs
Fixed field strength
What type of molecule makes up 500/0 to 90% of a person's total body weight?
Fat
Oxygen
Water
Nitrogen
Clinical MRl is based on the generation of signal from the nucleus of which atom?
Helium
Hydrogen
The nucleus of the hydrogen atom carries what type of charge?
Negative
Positive
Neutral
The spin of the proton of the hydrogen atom is known as
Nuclear spin
Axial momentum
Hydraulic spin
Angular momentum
Because the nucleus of the hydrogen atom acts much like a bar magnet it is said to have a
Magnetic ratio
Magnetic moment
Larmor ratio
Frequency ratio
Because the spinning nucleus of the hydrogen atom has both a North and South pole it is commonly called a
Electromagnet
Bar magnet
Dipole
When placed in an external magnetic field, hydrogen nuclei
Resonate
Become excited
Become aligned
Repel each other
After being placed in an external magnetic field, high energy hydrogen nuclei point in which direction?
Parallel
Anti-paired
Anti-parallel
Perpendicular
After being placed in an external magnetic field, low energy hydrogen nuclei point in which direction?
When placed in an external magnetic field, the hydrogen nuclei that are of clinical interest are
Parallel paired
Anti-parallel paired
Parallel unpaired
Perpendicular paired
When a patient is placed in an external magnetic field, the number of unmatched hydrogen protons usually equals
One billion
One million
Few per million
Few per billion
The sum of all of the unmatched parallel protons in an external magnetic field makes up what is called the
External magnetization
Internal magnetization
Resonant magnetization
Net magnetic vector
The type of rotation that is displayed by hydrogen nuclei in an external magnetic field is known as
Magnetization
Relaxation
Precession
Resonance
Within a perfect magnetic field all protons rotate at
Different frequencies
The same frequency
Undetermined frequencies
The speed at which protons rotate in an external magnetic field is known as
Precessional frequency
Hydromagnetic frequency
External magnetic frequency
The ratio that describes the constant at which any magnetic nucleus will precess in a 1 tesla magnet is known as
Precessional ratio
Magnetogyric ratio
Gyromagnetic ratio
Both B and C
The precessional frequency of magnetic nuclei is determined by which of the following?
The strength of the external magnetic field
The magnetogyric frequency
The gyromagnetic ratio of the specific nuclei
Both A and C
The equation that is used to determine the precessional frequency of magnetic nuclei is known as
Faraday's equation
Fast Fourier transformations
Damadian's equation
Larmor equation
The stronger the magnetic field the ________ the precessional frequency
Stronger
Higher
Longer
Shorter
Which of the following is the equation that is used to determine precessional frequencies?
Wo=yBo
Bo=yWo
F= yBo
Alignment of the net magnetic vector in the direction of the external magnetic field is known as
Transverse magnetization
Longitudinal magnetization
Equilibrium
B and C
Magnetization in the XY plane is known as
Spin-Lattice magnetization
When the proper radio frequency is applied, the precessing hydrogen nuclei begin to
Dephase
Rephase
Relax
The RF pulse used to move nuclei into a higher energy state is at a frequency known as
Resonance frequency
Fourier frequency
Transverse frequency
Hydrogen nuclei begin to precess in phase when which of the following occurs?
The proper RF is turned off
The patient is placed into the external magnet
The proper RF is turned on
When the radio frequency is turned off, precessing nuclei begin to
Lose energy
All of the above
Another name for transverse relaxation is
Spin-lattice relaxation
T1 relaxation
Spin-Spin relaxation
Longitudinal relaxation
Another name for Tl relaxation is
Dephasing
Transverse relaxation
The return of longitudinal magnetization to equilibrium is known as
Spin-Lattice relaxation
Dephasing of the net vector in the transverse plane is known as
The time it takes for a tissue's bulk longitudinal magnetization to return to 63% of its original value is known as
T1 relaxation time
T2 relaxation time
T2* relaxation time
None of the Above
The time it takes for transverse magnetization to decay to 37% of its original value is known as
Dephasing ofthe net vector in the transverse plane is caused by two factors, imperfections in the external magnetic field and
The application of the 180 degree RF pulse
The application of a 90 degree RF pulse
Interaction between surrounding nuclei
Magnetization in the transverse plane can also be known as
Mz
Mxy
M0
Magnetization in the longitudinal plane can also be known as
A and B
MRI signals can only be detected in which ofthe following planes
Z plane
XY plane
Transverse plane
~~ The signal created after applying a 90 degree RF pulse is known as a
Gradient echo signal
Spin echo
Spin spin signal
Fill signal
The signal produced after the 180 degree RF pulse is applied is known as a
Spin echo signal
A 180 degree RF pulse is used to ________ the dephasing net vector in the transverse plane
Magnetize
Decay
Delay
Refocus
The larger the net magnetic vector in the transverse plane the _______  the signal that is produced
Smaller
Weaker
The smaller the net magnetic vector in the transverse plane the signal that is produced
Larger
The letters FID in an Fill signal stand for
Field image dimensions
Free induction decay
Field induction direction
Free image direction
The type of signal that is created after a gradient is used to refocus the dephasing net vector is known as
The time between two successive 90 degree RF pulses is known as
Echo time
Repetition time
Inversion time
Relaxation time
The time between the 90 degree RF pulse and the spin echo signal in a spin echo pulse sequence is known as
In an inversion recovery pulse sequence, the time between the 180 degree RF pulse and the 90 degree RF pulse is known as
