At any one time, human body tissue, in general, is made up of 50 - 90% of what substance?
a. C13
b. NA 23
c. H²O
d. H - ANSWER H²O
Tissues that are very efficient at spin-lattice interactions near the Larmor frequency, such as
fatty tissues, should have:
Low T1 values and produces hyperintense signals.
High T1 values and produce hyperintense signals.
High T1 values and produce hypointense signals.
Low T1 values and produce hypointense signals. - ANSWER Low T1 values and produces
hyperintense signals.
The Larmor frequency of hydrogen protons in a 1.5 Tesla magnetic field is:
6.4 MHz/Tesla.
MHz/Tesla.
25.5 MHz/Tesla.
63.9 MHz/Tesla. - ANSWER 63.9 MHz/Tesla.
In clinical MR imaging of the human body, the substance of interest is:
1
,H.
NA23.
P31.
H²O. - ANSWER H. (hydrogen)
The main magnetic field of the MRI system is described as constant and always oriented in
one set direction, either horizontal or vertical (dependent on type of magnet). The
transmitted radio-frequency, in comparison, is described as:
Constant and always parallel to Bo.
Oscillating and always parallel to Bo.
Constant and always perpendicular to Bo.
Oscillating and always perpendicular to Bo. - ANSWER Oscillating and always
perpendicular to Bo.
The component Mxy is most associated with:
Anti-parallel to Bo; T1 relaxation; net magnetization.
Transverse to Bo; T2 relaxation; transverse magnetization.
Parallel to Bo; T1 relaxation; longitudinal magnetization.
Perpendicular to B1; T1 decay; FID. - ANSWER Transverse to Bo;
T2 relaxation;
transverse magnetization.
The T2 process is also known as:
Spin-Spin.
Spin density.
2
,Spin-Lattice.
Spin-warp. - ANSWER Spin-Spin.
Magnetic fields have strength and direction, which are represented by a:
Field line.
Axis.
Vector.
Gauss line. - ANSWER Vector.
Once in the main magnetic field, a majority of hydrogen protons will align themselves:
Anti-parallel to Bo.
Orthogonal to Bo.
Parallel to Bo.
Randomly in Bo - ANSWER Parallel to Bo.
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 it a:
Magnetic charge.
Magnetic spin.
Magnetic moment.
Magnetic precession. - ANSWER Magnetic moment.
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:
3
, 45 degrees.
60 degrees.
90 degrees.
180 degrees. - ANSWER 180 degrees.
MRI terms and symbols which are oriented with and superimposed on the symbol of Bo are:
-Transverse magnetization, Mxy, X axis, Y axis.
-Net magnetization, antiparallel, high energy level.
-Equilibrium, parallel, longitudinal magnetization, Mz, Z axis. - ANSWER Equilibrium,
parallel, longitudinal magnetization, Mz, Z axis.
In a large main magnetic field such as those employed in MRI, the motion of a hydrogen
proton has been described as wobbling like a spinning top. This motion is called:
A.Precession.
B.Resonance.
C.Frequency.
D.Angular momentum. - ANSWER A.Precession.
Methemoglobin and gadolinium based contrast agents have magnetic properties that
shorten both T1 and T2 values in adjacent tissues. What type of substances are they?
Diamagnetic.
Paramagnetic.
Superparamagnetic.
Ferromagnetic. - ANSWER Paramagnetic.
4
a. C13
b. NA 23
c. H²O
d. H - ANSWER H²O
Tissues that are very efficient at spin-lattice interactions near the Larmor frequency, such as
fatty tissues, should have:
Low T1 values and produces hyperintense signals.
High T1 values and produce hyperintense signals.
High T1 values and produce hypointense signals.
Low T1 values and produce hypointense signals. - ANSWER Low T1 values and produces
hyperintense signals.
The Larmor frequency of hydrogen protons in a 1.5 Tesla magnetic field is:
6.4 MHz/Tesla.
MHz/Tesla.
25.5 MHz/Tesla.
63.9 MHz/Tesla. - ANSWER 63.9 MHz/Tesla.
In clinical MR imaging of the human body, the substance of interest is:
1
,H.
NA23.
P31.
H²O. - ANSWER H. (hydrogen)
The main magnetic field of the MRI system is described as constant and always oriented in
one set direction, either horizontal or vertical (dependent on type of magnet). The
transmitted radio-frequency, in comparison, is described as:
Constant and always parallel to Bo.
Oscillating and always parallel to Bo.
Constant and always perpendicular to Bo.
Oscillating and always perpendicular to Bo. - ANSWER Oscillating and always
perpendicular to Bo.
The component Mxy is most associated with:
Anti-parallel to Bo; T1 relaxation; net magnetization.
Transverse to Bo; T2 relaxation; transverse magnetization.
Parallel to Bo; T1 relaxation; longitudinal magnetization.
Perpendicular to B1; T1 decay; FID. - ANSWER Transverse to Bo;
T2 relaxation;
transverse magnetization.
The T2 process is also known as:
Spin-Spin.
Spin density.
2
,Spin-Lattice.
Spin-warp. - ANSWER Spin-Spin.
Magnetic fields have strength and direction, which are represented by a:
Field line.
Axis.
Vector.
Gauss line. - ANSWER Vector.
Once in the main magnetic field, a majority of hydrogen protons will align themselves:
Anti-parallel to Bo.
Orthogonal to Bo.
Parallel to Bo.
Randomly in Bo - ANSWER Parallel to Bo.
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 it a:
Magnetic charge.
Magnetic spin.
Magnetic moment.
Magnetic precession. - ANSWER Magnetic moment.
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:
3
, 45 degrees.
60 degrees.
90 degrees.
180 degrees. - ANSWER 180 degrees.
MRI terms and symbols which are oriented with and superimposed on the symbol of Bo are:
-Transverse magnetization, Mxy, X axis, Y axis.
-Net magnetization, antiparallel, high energy level.
-Equilibrium, parallel, longitudinal magnetization, Mz, Z axis. - ANSWER Equilibrium,
parallel, longitudinal magnetization, Mz, Z axis.
In a large main magnetic field such as those employed in MRI, the motion of a hydrogen
proton has been described as wobbling like a spinning top. This motion is called:
A.Precession.
B.Resonance.
C.Frequency.
D.Angular momentum. - ANSWER A.Precession.
Methemoglobin and gadolinium based contrast agents have magnetic properties that
shorten both T1 and T2 values in adjacent tissues. What type of substances are they?
Diamagnetic.
Paramagnetic.
Superparamagnetic.
Ferromagnetic. - ANSWER Paramagnetic.
4
