The effects of main magnetic field inhomogeneities on the FID signal
are corrected for in a Spin-echo sequence by applying a second
radio- frequency pulse. The flip angle of this radio-frequency pulse is:
- ANSWER-
-180 degrees
Of the following statements, which describes part of the basic MR
imagingprocess? - ANSWER--Radio-frequency signals interact with
hydrogen protons
Which type of electromagnetic coils correct inhomogeneities in the
mainmagnetic field? - ANSWER--Shim coils
Immediately after an initial 90 degree radio-frequency pulse is
turned off,the hydrogen protons will begin to: - ANSWER--Dephase
Tissues that are very efficient at Spin-lattice interactions near the
Larmor frequency, such as fatty tissues, should have: - ANSWER--
Low T1 valuesand produces hyperintense signals
T1 is the measurement of time for the longitudinal component of the
net magnetization vector to recover what percentage of its original
value afterthe application of a 90 degree radio-frequency pulse? -
ANSWER--63%
The tissue characteristic which depends more on the state (solid,
liquid,gas) of a tissue than any other factor is: - ANSWER--T2 effects
,The basic process of MR signal generation contains two basic steps,
theyare: - ANSWER--Stimulation and relaxation
The T1 Process is also known as: - ANSWER--Spin-Lattice
The T2 process is also known as: - ANSWER--Spin-Spin
Once in the main magnetic field, a majority of hydrogen protons
will alignthemselves: - ANSWER--Parallel to B0
Magnetic resonance imaging is derived from the process
known as: -ANSWER--Nuclear magnetic resonance
The tissue characteristic that depends heavily on the relative content
of fatmolecules and free water is: - ANSWER--T1 effects
Which type of receiver radio-frequency coil is placed close to the
patient'sbody for the purpose of imaging superficial anatomic
structures? - ANSWER--Surface coils
An equation derived to predict the MR signal intensity of a particular
tissueas a result of a spin-echo pulse sequence is the: - ANSWER--
Larmor equation
,Which equation is true of the relaxation process? - ANSWER--
Without theeffects of T2 star, T2 decay continues
Because of the spinning motion of the hydrogen proton it has the
same properties as a bar magnet. The hydrogen proton's spinning
motion gives ita: - ANSWER--Magnetic moment
On a proton density image, two types of tissue that contain very
low concentrations of hydrogen appear very hypointense are:
(RESEARCHTHIS) - ANSWER--Cortical bone and lung
(RESEARCH THIS)
Magnetic susceptibility is defined as: (RESEARCH THIS) - ANSWER--
Tendency of a substance to attract or repel magnetic lines of force
which isdecided by the magnetic properties of its electrons
(RESEARCH THIS)
In comparison to Computed Axial Tomography, an advantage of
MRI is: -ANSWER--Superior soft-tissue contrast resolution
Fast transition phenomenon and entry phenomenon are theories
that explain which of the following tissue characteristics? -
ANSWER--Velocityeffects
In a loop of conductor in which an electric current is introduced and
maintained, a magnetic field will be produced in the center
perpendicular tothe flow of electric current. This is called: - ANSWER-
-Faraday's Law
, Which type of MRI magnet has attainable field strengths of 0.35
Tesla to 3Tesla for clinical use in the U.S.A, and higher strengths
elsewhere and in research? - ANSWER--Superconcuctive
The Process of relaxation begins when - ANSWER--B1 is turned off
A sinewave is a symbol used to measure electromagnetic energy. A
sinewave's two components of measure are: - ANSWER--Wavelength
andfrequency
Magnetic fields have direction which are usually designated as north
andsouth, therefore magnetic fields are described as: - ANSWER--
Dipoles
At any one time, human body tissue, in general, is made up of 50-
90%: -ANSWER--H(Hydrogen)
Once the net magnetization vector (NMV) has moved away from
equilibrium the following will occur: - ANSWER--The transverse
componentwill increase
The T1 process is also known as: - ANSWER--Spin-Lattice
Which of the following is the Larmor equation? - ANSWER--W0=Y+B0
are corrected for in a Spin-echo sequence by applying a second
radio- frequency pulse. The flip angle of this radio-frequency pulse is:
- ANSWER-
-180 degrees
Of the following statements, which describes part of the basic MR
imagingprocess? - ANSWER--Radio-frequency signals interact with
hydrogen protons
Which type of electromagnetic coils correct inhomogeneities in the
mainmagnetic field? - ANSWER--Shim coils
Immediately after an initial 90 degree radio-frequency pulse is
turned off,the hydrogen protons will begin to: - ANSWER--Dephase
Tissues that are very efficient at Spin-lattice interactions near the
Larmor frequency, such as fatty tissues, should have: - ANSWER--
Low T1 valuesand produces hyperintense signals
T1 is the measurement of time for the longitudinal component of the
net magnetization vector to recover what percentage of its original
value afterthe application of a 90 degree radio-frequency pulse? -
ANSWER--63%
The tissue characteristic which depends more on the state (solid,
liquid,gas) of a tissue than any other factor is: - ANSWER--T2 effects
,The basic process of MR signal generation contains two basic steps,
theyare: - ANSWER--Stimulation and relaxation
The T1 Process is also known as: - ANSWER--Spin-Lattice
The T2 process is also known as: - ANSWER--Spin-Spin
Once in the main magnetic field, a majority of hydrogen protons
will alignthemselves: - ANSWER--Parallel to B0
Magnetic resonance imaging is derived from the process
known as: -ANSWER--Nuclear magnetic resonance
The tissue characteristic that depends heavily on the relative content
of fatmolecules and free water is: - ANSWER--T1 effects
Which type of receiver radio-frequency coil is placed close to the
patient'sbody for the purpose of imaging superficial anatomic
structures? - ANSWER--Surface coils
An equation derived to predict the MR signal intensity of a particular
tissueas a result of a spin-echo pulse sequence is the: - ANSWER--
Larmor equation
,Which equation is true of the relaxation process? - ANSWER--
Without theeffects of T2 star, T2 decay continues
Because of the spinning motion of the hydrogen proton it has the
same properties as a bar magnet. The hydrogen proton's spinning
motion gives ita: - ANSWER--Magnetic moment
On a proton density image, two types of tissue that contain very
low concentrations of hydrogen appear very hypointense are:
(RESEARCHTHIS) - ANSWER--Cortical bone and lung
(RESEARCH THIS)
Magnetic susceptibility is defined as: (RESEARCH THIS) - ANSWER--
Tendency of a substance to attract or repel magnetic lines of force
which isdecided by the magnetic properties of its electrons
(RESEARCH THIS)
In comparison to Computed Axial Tomography, an advantage of
MRI is: -ANSWER--Superior soft-tissue contrast resolution
Fast transition phenomenon and entry phenomenon are theories
that explain which of the following tissue characteristics? -
ANSWER--Velocityeffects
In a loop of conductor in which an electric current is introduced and
maintained, a magnetic field will be produced in the center
perpendicular tothe flow of electric current. This is called: - ANSWER-
-Faraday's Law
, Which type of MRI magnet has attainable field strengths of 0.35
Tesla to 3Tesla for clinical use in the U.S.A, and higher strengths
elsewhere and in research? - ANSWER--Superconcuctive
The Process of relaxation begins when - ANSWER--B1 is turned off
A sinewave is a symbol used to measure electromagnetic energy. A
sinewave's two components of measure are: - ANSWER--Wavelength
andfrequency
Magnetic fields have direction which are usually designated as north
andsouth, therefore magnetic fields are described as: - ANSWER--
Dipoles
At any one time, human body tissue, in general, is made up of 50-
90%: -ANSWER--H(Hydrogen)
Once the net magnetization vector (NMV) has moved away from
equilibrium the following will occur: - ANSWER--The transverse
componentwill increase
The T1 process is also known as: - ANSWER--Spin-Lattice
Which of the following is the Larmor equation? - ANSWER--W0=Y+B0
