MRI Registry Exam A+ Pass 2025
Verified
gradient rise time - Answer- the time it takes for the gradient to reach its full amplitude
gradient slew rate - Answer- the speed rate of ascent or descent of a gradient from zero
to its maximum amplitude,
duty cycle - Answer- the time the gradients are on during a TR period, the "gradient
working time."
A 6 inch surface coil is able to receive how much signal ? - Answer- 3 inches
When going from a linear coil to a quadrature coil, SNR is increased by - Answer- 40%.
The intensity limit for a static magnetic field in clinical use is limited by the Food and
Drug Administration (FDA) to ? - Answer- 4.0 Tesla (T) field strength for all patients, but
8 Tesla for all patients over 1 month of age.
The liquid cryogens are cooled in superconducting magnet at a temperature of? -
Answer- 4º Kelvin.
Consistent room temperature of _____, humidity of ________, and sufficient air flow in
the MR scan room is recommended to make patients less vulnerable to the RF heating
effects. - Answer- 65-75°F, 50-70%
Which sequences can have more of a detrimental effect on patients with regards to time
varying magnetic fields? - Answer- EPI (Echo Planar Imaging)
Oscillating magnetic fields (radiofrequency) primary biological effect is? - Answer-
..tissue heating /deposition.
The resonance frequency in a 1.5 Tesla magnet is? - Answer- 63.86 Mhz.
The difference in chemical shift is approximately ? - Answer- 3.5 parts-per-million (ppm)
1 Tesla 147hz (1.5Tesla - 220 Hz 3Tesla - 440 Hz)
T1 relaxation occurs when nuclei give up their energy to the surrounding tissue, which is
known as? - Answer- spin lattice relaxation
T1 relaxation (recovery) time is the recovery of ____% longitudinal magnetization -
Answer- 63%
, T2 relaxation (Decay) time is defined as the time it takes for ___% of the transverse
magnetization to
decay, - Answer- 63% or to de-phase to 37% of their original value
The return of the transverse magnetization to its equilibrium value, zero (T2 decay) -
Answer- Spin-spin relaxation -
Hydrogen in fat recovers more rapidly along the longitudinal axis than water and loses
transverse magnetization faster than water - Answer- ...
When increasing NEX/NSA, SNR (signal-to-noise ratio) increases by the? - Answer-
square root (√) of the % increase. 2 NEX, increased to 6 NEX (3times the total NEX)
would have an increase in SNR of √3,
A method of reducing MRI scan time by not filling as many lines of k-space in the phase
direction, while maintaining spatial resolution, is known as - Answer- Rectangular FOV
What is defined as the storage location of MR signal data? - Answer- k-space
Referring to k-space, the data containing high resolution are located along the ? -
Answer- outer lines
Referring to k-space, the data containing signal and contrast information are located
along the? - Answer- central lines.
High amplitude signals are stored in what part of k-space? - Answer- center
Acquiring a bit more than half the phase dimension k-space samples, then
interpolating the data with zeroes for the remaining half is a technique known as ? -
Answer- Half Fourier, or Zero Fill.
what is when only half the views of k-space are filled in the frequency axis, an
acceleration technique used to shorten TR and TE? - Answer- Partial or fractional echo
Collecting the low frequency (high amplitude signal) data points in k-space at the start of
the scan (in a spiral fashion) is known as - Answer- elliptic centric k-space filling
The high amplitude signals are stored in the center of k-space, where
______information is also found. - Answer- contrast/max signal
what sequence usually require an interslice gap? - Answer- 2D acquisitions
Which sequence provides greater SNR and elimination of crosstalk artifacts? - Answer-
3D sequence does
Verified
gradient rise time - Answer- the time it takes for the gradient to reach its full amplitude
gradient slew rate - Answer- the speed rate of ascent or descent of a gradient from zero
to its maximum amplitude,
duty cycle - Answer- the time the gradients are on during a TR period, the "gradient
working time."
A 6 inch surface coil is able to receive how much signal ? - Answer- 3 inches
When going from a linear coil to a quadrature coil, SNR is increased by - Answer- 40%.
The intensity limit for a static magnetic field in clinical use is limited by the Food and
Drug Administration (FDA) to ? - Answer- 4.0 Tesla (T) field strength for all patients, but
8 Tesla for all patients over 1 month of age.
The liquid cryogens are cooled in superconducting magnet at a temperature of? -
Answer- 4º Kelvin.
Consistent room temperature of _____, humidity of ________, and sufficient air flow in
the MR scan room is recommended to make patients less vulnerable to the RF heating
effects. - Answer- 65-75°F, 50-70%
Which sequences can have more of a detrimental effect on patients with regards to time
varying magnetic fields? - Answer- EPI (Echo Planar Imaging)
Oscillating magnetic fields (radiofrequency) primary biological effect is? - Answer-
..tissue heating /deposition.
The resonance frequency in a 1.5 Tesla magnet is? - Answer- 63.86 Mhz.
The difference in chemical shift is approximately ? - Answer- 3.5 parts-per-million (ppm)
1 Tesla 147hz (1.5Tesla - 220 Hz 3Tesla - 440 Hz)
T1 relaxation occurs when nuclei give up their energy to the surrounding tissue, which is
known as? - Answer- spin lattice relaxation
T1 relaxation (recovery) time is the recovery of ____% longitudinal magnetization -
Answer- 63%
, T2 relaxation (Decay) time is defined as the time it takes for ___% of the transverse
magnetization to
decay, - Answer- 63% or to de-phase to 37% of their original value
The return of the transverse magnetization to its equilibrium value, zero (T2 decay) -
Answer- Spin-spin relaxation -
Hydrogen in fat recovers more rapidly along the longitudinal axis than water and loses
transverse magnetization faster than water - Answer- ...
When increasing NEX/NSA, SNR (signal-to-noise ratio) increases by the? - Answer-
square root (√) of the % increase. 2 NEX, increased to 6 NEX (3times the total NEX)
would have an increase in SNR of √3,
A method of reducing MRI scan time by not filling as many lines of k-space in the phase
direction, while maintaining spatial resolution, is known as - Answer- Rectangular FOV
What is defined as the storage location of MR signal data? - Answer- k-space
Referring to k-space, the data containing high resolution are located along the ? -
Answer- outer lines
Referring to k-space, the data containing signal and contrast information are located
along the? - Answer- central lines.
High amplitude signals are stored in what part of k-space? - Answer- center
Acquiring a bit more than half the phase dimension k-space samples, then
interpolating the data with zeroes for the remaining half is a technique known as ? -
Answer- Half Fourier, or Zero Fill.
what is when only half the views of k-space are filled in the frequency axis, an
acceleration technique used to shorten TR and TE? - Answer- Partial or fractional echo
Collecting the low frequency (high amplitude signal) data points in k-space at the start of
the scan (in a spiral fashion) is known as - Answer- elliptic centric k-space filling
The high amplitude signals are stored in the center of k-space, where
______information is also found. - Answer- contrast/max signal
what sequence usually require an interslice gap? - Answer- 2D acquisitions
Which sequence provides greater SNR and elimination of crosstalk artifacts? - Answer-
3D sequence does
