MRI IN Practice Final Exam with All Correct & 100%
Verified Answers |Actual Complete Exam| Already
Graded A+
Resonance ✔Correct Answer-A phenomenon that occurs when two objects naturally vibrate at the
same frequency.
Results of resonance ✔Correct Answer-The direction of the NVM shifts as they transition to high
energy. Away from Bo
The angle to which the NMV moves out of alignment with the Bo is called FLIP ANGLE
Effect of RF Pulse ✔Correct Answer-1)hydrogen protons absorbs the RF energy
2)increases the # of spin down hydrogen nuclei
SPIN UP NUCLEI GAIN ENERGY THROUGH RESONANCE
Flip angle ✔Correct Answer-the angle to which the longitudinal magnetization is tipped into the
transverse plane, following the initial RF excitation pulse
Faraday's Law ✔Correct Answer-When a conductive receiver coil is placed in the area of a moving
magnetic field, a voltage is induced in it.
Resonance causes protons to precession in phase in the transverse plane, this generates an electric
current.
The MR signal is produced when when in-phase magnetization cuts across the coil.
Magnitude of MR signal ✔Correct Answer-Depends on the amount of magnetization present in the
transverse plane
-Small magnetization transverse plane=LOW SIGNAL {Hypo-intense, DARK}
-Large magnetization=HIGH SIGNAL {hyper-intense, BRIGHT}
relaxation ✔Correct Answer-The process by which hydrogen transition back to low energy state.
When the RF pulse is removed the NMV, the NMV is influenced by Bo:
1.The protons move out of phase (dephase) with each other causing the transverse magnetization to
slowly disappear.
2.Protons return to lower energy level (relax) to the resting state of net longitudinal magnetization
(Mz)
Free Induction Decay Signal (FID) ✔Correct Answer-The loss of signal/voltage
As the transverse magnetization decreases, so does the magnitude induced in the receiver coil.
This occurs by the inhomogeneities, causing the protons to lose coherency (deodars)
pulse sequence ✔Correct Answer-a series of RF pulses, gradient applications and intervening time
periods
Dramatically impacts the appearance of a MRI image
MRI obtain various contrast images using pulse sequence.
All help to visualize different anatomy and pathology
pulse timing parameters ✔Correct Answer-a. A sequence of transmitting rf pulses during precise
times with interviening periods of recovery.
, Repetition Time (TR)
Echo Time (TE)
Echo Time (TE) ✔Correct Answer-Time in milliseconds from the application of the RF pulse to the
peak of the signal induced in the coil. TE determines how much decay of transverse magnetization is
allowed to occur
Intrinsic Contrast Parameters ✔Correct Answer-those parameters that cannot be changed because
they are inherent to the body's tissues
T1 recovery time
T2 Decay Time
Proton density
Flow
Apparent diffusion coefficient (ADC)
Extrinsic Contrast Parameters ✔Correct Answer-those parameters that can be changed at the
operator console
Repetition time (TR)
Echo time (TE)
Flip angle
Inversion Time (TI)
Turbo factor or echo train Length (ETL)
T1 RECOVERY (SPIN LATTICE RELAXATION) ✔Correct Answer-Recovery of longitudinal
magnetization
(Gradually INCREASES).
Time it takes the protons to recover 63% of its longitudinal magnetization
Involves the nuclei giving up their energy to the surrounding environment
Occurs at different rates in different tissues
Repetition Time (TR) ✔Correct Answer-time between each excitation pulse
T2 Decay (Spin spin relaxation) ✔Correct Answer-loss of transverse magnetization as a result of
spin-spin relaxation
Interactions between neighboring nuclei cause dephasing (energy loss)
Involves loss of phase coherence
T2 Decay Time ✔Correct Answer-The time it takes 63% of the transverse magnetization to dephase
(37% in-phase) in a tissue.
The rate of decay is also an exponential process & occurs in different tissues.
T2* Decay ✔Correct Answer-Caused by the immediate deplaning of spins in the transverse Mxy
plane once the RF pulse is turned off.
Detected by receiver coil immediately after the termination of the RF pulse.
Happens 10x faster than T2.
Why T2* is faster than T2 ✔Correct Answer-1)Dephasing due to magnetic field inhomogeneities
*inhomogeneities may be result of intrinsic defect in magnet
*magnetic susceptibility effects produced by the tissue/patient or other materials placed within the
field
2)T2 decay itself; the inherent tissue in T2 decay takes longer to dephase
Verified Answers |Actual Complete Exam| Already
Graded A+
Resonance ✔Correct Answer-A phenomenon that occurs when two objects naturally vibrate at the
same frequency.
Results of resonance ✔Correct Answer-The direction of the NVM shifts as they transition to high
energy. Away from Bo
The angle to which the NMV moves out of alignment with the Bo is called FLIP ANGLE
Effect of RF Pulse ✔Correct Answer-1)hydrogen protons absorbs the RF energy
2)increases the # of spin down hydrogen nuclei
SPIN UP NUCLEI GAIN ENERGY THROUGH RESONANCE
Flip angle ✔Correct Answer-the angle to which the longitudinal magnetization is tipped into the
transverse plane, following the initial RF excitation pulse
Faraday's Law ✔Correct Answer-When a conductive receiver coil is placed in the area of a moving
magnetic field, a voltage is induced in it.
Resonance causes protons to precession in phase in the transverse plane, this generates an electric
current.
The MR signal is produced when when in-phase magnetization cuts across the coil.
Magnitude of MR signal ✔Correct Answer-Depends on the amount of magnetization present in the
transverse plane
-Small magnetization transverse plane=LOW SIGNAL {Hypo-intense, DARK}
-Large magnetization=HIGH SIGNAL {hyper-intense, BRIGHT}
relaxation ✔Correct Answer-The process by which hydrogen transition back to low energy state.
When the RF pulse is removed the NMV, the NMV is influenced by Bo:
1.The protons move out of phase (dephase) with each other causing the transverse magnetization to
slowly disappear.
2.Protons return to lower energy level (relax) to the resting state of net longitudinal magnetization
(Mz)
Free Induction Decay Signal (FID) ✔Correct Answer-The loss of signal/voltage
As the transverse magnetization decreases, so does the magnitude induced in the receiver coil.
This occurs by the inhomogeneities, causing the protons to lose coherency (deodars)
pulse sequence ✔Correct Answer-a series of RF pulses, gradient applications and intervening time
periods
Dramatically impacts the appearance of a MRI image
MRI obtain various contrast images using pulse sequence.
All help to visualize different anatomy and pathology
pulse timing parameters ✔Correct Answer-a. A sequence of transmitting rf pulses during precise
times with interviening periods of recovery.
, Repetition Time (TR)
Echo Time (TE)
Echo Time (TE) ✔Correct Answer-Time in milliseconds from the application of the RF pulse to the
peak of the signal induced in the coil. TE determines how much decay of transverse magnetization is
allowed to occur
Intrinsic Contrast Parameters ✔Correct Answer-those parameters that cannot be changed because
they are inherent to the body's tissues
T1 recovery time
T2 Decay Time
Proton density
Flow
Apparent diffusion coefficient (ADC)
Extrinsic Contrast Parameters ✔Correct Answer-those parameters that can be changed at the
operator console
Repetition time (TR)
Echo time (TE)
Flip angle
Inversion Time (TI)
Turbo factor or echo train Length (ETL)
T1 RECOVERY (SPIN LATTICE RELAXATION) ✔Correct Answer-Recovery of longitudinal
magnetization
(Gradually INCREASES).
Time it takes the protons to recover 63% of its longitudinal magnetization
Involves the nuclei giving up their energy to the surrounding environment
Occurs at different rates in different tissues
Repetition Time (TR) ✔Correct Answer-time between each excitation pulse
T2 Decay (Spin spin relaxation) ✔Correct Answer-loss of transverse magnetization as a result of
spin-spin relaxation
Interactions between neighboring nuclei cause dephasing (energy loss)
Involves loss of phase coherence
T2 Decay Time ✔Correct Answer-The time it takes 63% of the transverse magnetization to dephase
(37% in-phase) in a tissue.
The rate of decay is also an exponential process & occurs in different tissues.
T2* Decay ✔Correct Answer-Caused by the immediate deplaning of spins in the transverse Mxy
plane once the RF pulse is turned off.
Detected by receiver coil immediately after the termination of the RF pulse.
Happens 10x faster than T2.
Why T2* is faster than T2 ✔Correct Answer-1)Dephasing due to magnetic field inhomogeneities
*inhomogeneities may be result of intrinsic defect in magnet
*magnetic susceptibility effects produced by the tissue/patient or other materials placed within the
field
2)T2 decay itself; the inherent tissue in T2 decay takes longer to dephase
