Part D Flashcards
What would be the appearance of cerebrospinal fluid on a transverse image of the brain using the following spin echo sequence parameters. TR / TE 500 / 8
a) hyperintense to white matter
b) isointense to fat
c) hypointense to white matter
d) none of the above
c) hypointense to white matter
A T2 weighted spin echo sequence is characterised by parameters as listed below
a) Long TR/Short TE
b) Short TR/Long TE
c) Short TR/Short TE
d) Long TR/Long TE
d) Long TR/Long TE
The B line of the pulse sequence in this image relate to ________ encoding
a) Slice selection
b) Frequency
c) Phase
d) Fat Suppression
a) slice selection
Which of the following is true when referring to a half NEX or partial Fourier sequences?
a) spatial resolution is reduced
b) SNR is reduced
c) Less susceptible to periodic motion
d) increase in scan time
b) SNR is reduced
In 2D SE imaging the scan time is calculated by TR x NEX x PE?
a) True
b) False
a) true
On a 4 ETL T1 weighted FSE/TSE sagittal knee sequence increasing the echo spacing or minimum allowable TE will increase the amount of image blurring.
a) True
b) False
a) true
lesser ETL or turbo factor = less image blurring
Which of the following T2 weighted FSE/TSE sequences will produce the sharpest images. Echo spacing and TE are constant.
a) ETL 20
b) ETL 64
c) ETL 8
a) ETL 20
The purpose of a FLAIR sequence is to provide T2 weighted sequence that enhances the CSF?
False
Which of the following factors will influence SAR in a T1 weighted sequence
a) patient weight
b) TR
c) type of T1 weighted sequence used
d) coil type
e) all of the above
e) all of the above
Which of the following tissues are more commonly suppressed using magnetisation transfer?
a) Fat
b) grey and white matter
c) CSF and Fat
d) grey matter, white matter and fat
d) grey matter, white matter and fat
MTC is used for vascular MRI, nulls other brain tissue
In half NEX imaging, it is only necessary to acquire half of the phase encoding steps
a) true
b) false
a) true
Pulsatile motion artefacts occur in both phase and frequency directions
a) true
b) false
b) False
Periodic pulsatile motion results in coherent ghosts whereas random motion results in image blurring.
a) true
b) false
a) true
This image demonstrates pulsatile flow due to the venous sinus. Which of the following sequence choices or options would potentially reduce the artefact.
a) Flow Compensation (GMR)
b) Pulse (peripheral triggering)
c) Respiratory gating
d) a and b
d) a and b
The artefact demonstrated in this image represents truncation. True or False
a) true
Fix this by increasing the matrix to decrease the chance of truncation/Gibbs/ringing or psuedosyrnix
The artefact demonstrated on the multi-slice/multi-angle sagittal oblique T2 FSE in this image is due to:
a) coil failure
b) Interslice cross excitation
Changes to the transmit bandwidth will effect:
a) phase encode amplitude
b) slice thickness
c) frequency amplitude
d) readout time
b) slice thickness
slice thickness proportional to transmit bandwidth
Chemical shift artefact can be reduced by:
a) increasing receive bandwidth
b) increasing the NSA
c) using a lower matrix
a) increasing receive bandwidth
In a conventional 2D SE sequence, the slice selection gradient is applied _______.
a) only once being after the PE gradient
b) during the sampling of the echo
c) only once being before the PE gradient
d) during the 90 degree pulse and during the 180 degree pulse
d) during the 90 degree pulse and during the 180 degree pulse
A GRE sequence that uses a gradient to remove residual transverse magnetisation prior to the next excitation pulse is referred to as a _______ GRE.
a) reduced
b) optimised
c) steady state
d) spoiled
d) spoiled
A GRE pulse sequence uses a _______ to produce an echo
a) gradient magnetic field
b) 180 degree RF pulse
c) combination of a and b
d) switching device
a) gradient magnetic field
In diffusion weighted imaging the b value represents:
a) intensity of the magnetic field
b) the size of the diffusion gradient
c) length of acquisition
d) area covered by the acquisition
b) the size of the diffusion gradient
b = amplitude, strength, duration of the applied gradient
Increasing the amplitude of the slice selecting gradient will _______ the slice thickness.
a) reduce
b) increase
c) have no effect on
d) exponentially decrease
a) reduce
in a conventional SE sequence with a phase encoding matrix of 256, how many times must the TR be repeated in an acquisition using 4 NSA?
a) 512
b) 128
c)1024
d) 256
c) 1024
Assuming a TR of sufficient time to allow for full recovery of longitudinal magnetisation, selecting a T1 that is _______ of a tissues T1 time will null the signal from that tissue.
a) 69%
b) 63%
c) 27%
d) 98%
a) 69%
T1 to null signal from tissue 0.69 times its T1 relaxation
The peak signal strength of a spin echo is less than that of the FID due to ________
a) T2 relaxation
b) T1 decay
c) chemical shift
d) T2* enhancement
a) T2 relaxation
Using a zero fill technique to reduce scan time will also reduce
a) SNR
b) spatial resolution
c) flow artifacts
d) b and c
A) SNR
Increasing the NSA or NEX will cause an increase in _________?
a) SNR
b) scan time
c) spatial resolution
d) a and b
B) scan time
Reducing the NSA/NEX will cause an increase in _______________?
a) SNR
b) spatial resolution
c) flow artifacts
d) b and c
a) SNR
Which of the following MRA sequences is the most insensitive to slow flow?
a) 3D TOF
b) 2D TOF
c) 2D PC (VENC = 30cm/sec)
d) 3D PC (VENC = 20cm/sec)
a) 3D TOF
A sequence using a FOV of 22cm, acquisition matrix of 256 frequency, 192 phase, 5mm slice thickness and 2.5mm spacing will have a voxel volume of:
a) 4.94 cm^2
b) 3.99 cm^3
c) 1.15cm^3
d) 4.95cm^3
D) 4.95cm^3
(220/192) * (220/256) * (5) =
Increasing the TE
a) increases the contrast based on T2 relaxation times of the tissues
b) reduces the contrast based on T2 relaxation times of the tissues
c) reduces the contrast based on T1 relaxation times of the tissues
d) a and c
d) a and c
Increasing the TE has what effect on the number of slices available?
a)increases
b) decreases
c) has no effect on number of slices
d) increases slices by 1/TR
b) decreases
In a GRE sequence, increasing the flip angle while holding the TR contrast increases _____?
a) T2* contrast weighting
b) spin density contrast weighting
c) saturation
d) scan time
c) saturation
Which of the following can be employed to reduce artifacts from flow?
a) spatial presentation
b) flow compensation
c) increased NSA/NEX
d) all of the above
d) all of the aboveWh
Which of the following, if any, is helpful in reducing artifactual signal loss in a 3D TOF sequence of the intracranial vasculature?
a) reduced slice thickness
b) reduced receiver bandwidth
c) a and b
d) none of the above
c) a and b
This pulse sequence diagram relates to what sort of sequence?
2D GRE
You are asked to run a sequence that is susceptible to haemosiderin. Which of the following are more susceptible to haemosiderin?
a) Conventional SE T1
b) Conventional SE T2
c) FSE T2 ETL 64
d) GRE with TE 35ms/Flip 20 degrees
GRE with TE 35ms/Flip 20 degrees,
GRE sequence do not have a 180-degree refocussing pulse, therefore are more susceptible to haemosiderin.
A typical Inversion Recovery sequence follows what pulses?
180-deg, 90-deg, 180-deg etc….
Images 10 and 11 are often used in adrenal scans to determine what type of tissue content of the lesion?
a) fat
b) water
c) silicone
d) bone
a) fat
IP & OOP imaging is to differentiate between lipid-rich and non-lipid containing adrenal lesions.
What would be the appearance of CSF on a transverse image of the brain using the following inversion recovery sequence parameters -TR9000/TI2000
a) hyperintense to white matter
b) isointense to fat
c) hypointense to white matter
d) isointense to water
c) hypointense to white matter
A given conventional spin echo pulse sequences take up to 12 minutes to acquire. If all other factors are the same, using a fast spin echo sequence using an ETL of 4 will take how many minutes?
3 minutes
A chemical or spectral fat suppression sequence will suppress the signal from fat based on the:
a) precessional frequency of fat
b) amount of fat in the target slice
c) T2 relaxation time of fat
d) water as the centre frequency
a) precessional frequency of fat
Dynamic steady state MRA sequences of the renal arteries are performed with the use of:
a) incoherent GRE
b) coherent GRE
c) Steady-state gradient echoes
d) T2* GRE
a) incoherent GRE (also known as spoiled residual transverse magnetisation)
In a conventional 2D spin echo sequence, when is the slice selection gradient applied?
a) only once being after the phase encoding gradient
b) during the sampling of the echo
c) only once being before the phase encoding gradient
d) during the 90-degree pulse and during the 180-degree pulse
d) during the 90-degree pulse and during the 180-degree pulse.
In a SE sequence, slice selection gradient turns on at the same time as:
a) 90 and 180-degree RF pulses
b) frequency encoding
c) phase encoding
d) readout gradient
a) 90 and 180 degree RF pulses
A GRE sequence that uses a gradient to remove residual transverse magnetisation prior to the next excitation pulse is referred to as what type of gradient echo?
a) reduced
b) optimised
c) steady state
d) spoiled
d) spoiled
GRE sequences acquired for high signal from fluid are known as all of the following EXCEPT:
a) incoherent GRE
b) coherent gradient echoes
c)T2* gradient echoes
d) Steady-state gradient echoes
a) incoherent GRE (RF spoiled)
In a balanced GRE acquisition, the contrast weighting is:
a) T2 weighted
b) T2* weighted
c) T1 weighted
d) weighted for the ratio of T2/T1
d) weighted for the ratio of T2/T1
Parallel imaging techniques are also known as all of the following EXCEPT:
a) SAT
b) SMASH
c) SENSE
d) GRAPPA
a) SAT
The gradient characteristic that reflects both strength and speed is known as:
a) amplitude
b) slew rate
c) duty cycle
d) rise time
b) slew rate
