MRI Physics Final Test 2024/2025(Questions With 100%
Correct Answers)A+ Graded Verified
all the following are artifacts in MRI except - ANSWER beam hardening
_____ is defined as the strength of the gradient over distance - ANSWER slew rate
.5T is equal to _____ Gauss. - ANSWER 5,000
A FLAIR inversion sequence is utilized to null - ANSWER CSF
A STIR inversion sequence is utilized to null - ANSWER fat
a double echo, spin echo pulse sequence normally results in ____ - ANSWER T2 and proton
density weighted
an inversion recovery is a pulse sequence that begins with a ____ degree inverting pulse -
ANSWER 180
a second (or additional) spin or wobble of the magnetic moment is defined as_____ -
ANSWER precession
hydrogen precesses at approximately ______ MHz/T in a .5T MRI unit - ANSWER 21
the time taken to rephase after the application of the 180 degree RF equals the time to dephase
when the - ANSWER TAU
______ reflects the relationship balance between spin up and spin down nuclei. - ANSWER
net magnetification vector
"active" shielding work to ____ , while passive shielding work to _____ - ANSWER shrink the
magnetic field, contain the magnetic field
to "null" a signal is to _____ a signal - ANSWER reduce
data points in k-space are converted to frequency amplitude in the frequency domain by a
process called - ANSWER fast fourier transfer
which of the following is incorrect? - ANSWER data acquired in the central lines of k-space
contribute to resolution, while data acquired in the outer lines contribute to
_____ extrapolates right side data and places it on the left side - ANSWER partial echo
imaging
, for which of the following is it crucial to have a TR that is shorter than the T1 and T2 times of the
tissue - ANSWER steady state
homogeneity is measured in: - ANSWER ppm
how does increasing the sampling time affect the minimum TE time? - ANSWER increase
If i want to increase image resolution, I would _____ slice thickness - ANSWER decrease
if only a single RF pulse were applied, what flip angle would produce the optimal signal return? -
ANSWER 90
if the gyromagnetic ratio of a substance is 2Mhz/ tesla and the magnetic field strength is 10
Telsa, then the - ANSWER 20 Mhz
if the matrix is increased, what happens to SNR? - ANSWER decrease
if we increase the NEX from 1 to 4, our scan time will _____ - ANSWER increase by a factor
of 4
if you decrease receive bandwidth, you _____ SNR - ANSWER increase
if you increase matrix, you increase resolution and ____ scan time - ANSWER increase
if you increase the matrix size and keep the FOV the same, the pixel size will: - ANSWER
decrease
in a pulse sequence utilizing 2 echoes, the first image is typically a ____ image, while the
second is a - ANSWER proton density
in a time of flight sequence, the tissue is hypointense relative to the flowing blood because of: -
ANSWER saturation effects
in fast spin echo weighting, the _____ encoding slopes are centered on the effective TE
selected. - ANSWER shallow
what is the unit of measurement for the strength of the gradient magnetic field? - ANSWER
mT/m
it is recommended that that the general public those persons who have not been properly
screened for the effect - ANSWER 25G
matter unaffected by a magnetic field is termed: - ANSWER diamagnetic
Correct Answers)A+ Graded Verified
all the following are artifacts in MRI except - ANSWER beam hardening
_____ is defined as the strength of the gradient over distance - ANSWER slew rate
.5T is equal to _____ Gauss. - ANSWER 5,000
A FLAIR inversion sequence is utilized to null - ANSWER CSF
A STIR inversion sequence is utilized to null - ANSWER fat
a double echo, spin echo pulse sequence normally results in ____ - ANSWER T2 and proton
density weighted
an inversion recovery is a pulse sequence that begins with a ____ degree inverting pulse -
ANSWER 180
a second (or additional) spin or wobble of the magnetic moment is defined as_____ -
ANSWER precession
hydrogen precesses at approximately ______ MHz/T in a .5T MRI unit - ANSWER 21
the time taken to rephase after the application of the 180 degree RF equals the time to dephase
when the - ANSWER TAU
______ reflects the relationship balance between spin up and spin down nuclei. - ANSWER
net magnetification vector
"active" shielding work to ____ , while passive shielding work to _____ - ANSWER shrink the
magnetic field, contain the magnetic field
to "null" a signal is to _____ a signal - ANSWER reduce
data points in k-space are converted to frequency amplitude in the frequency domain by a
process called - ANSWER fast fourier transfer
which of the following is incorrect? - ANSWER data acquired in the central lines of k-space
contribute to resolution, while data acquired in the outer lines contribute to
_____ extrapolates right side data and places it on the left side - ANSWER partial echo
imaging
, for which of the following is it crucial to have a TR that is shorter than the T1 and T2 times of the
tissue - ANSWER steady state
homogeneity is measured in: - ANSWER ppm
how does increasing the sampling time affect the minimum TE time? - ANSWER increase
If i want to increase image resolution, I would _____ slice thickness - ANSWER decrease
if only a single RF pulse were applied, what flip angle would produce the optimal signal return? -
ANSWER 90
if the gyromagnetic ratio of a substance is 2Mhz/ tesla and the magnetic field strength is 10
Telsa, then the - ANSWER 20 Mhz
if the matrix is increased, what happens to SNR? - ANSWER decrease
if we increase the NEX from 1 to 4, our scan time will _____ - ANSWER increase by a factor
of 4
if you decrease receive bandwidth, you _____ SNR - ANSWER increase
if you increase matrix, you increase resolution and ____ scan time - ANSWER increase
if you increase the matrix size and keep the FOV the same, the pixel size will: - ANSWER
decrease
in a pulse sequence utilizing 2 echoes, the first image is typically a ____ image, while the
second is a - ANSWER proton density
in a time of flight sequence, the tissue is hypointense relative to the flowing blood because of: -
ANSWER saturation effects
in fast spin echo weighting, the _____ encoding slopes are centered on the effective TE
selected. - ANSWER shallow
what is the unit of measurement for the strength of the gradient magnetic field? - ANSWER
mT/m
it is recommended that that the general public those persons who have not been properly
screened for the effect - ANSWER 25G
matter unaffected by a magnetic field is termed: - ANSWER diamagnetic
