Part C: Pulse sequences Flashcards
- An inversion recovery (IR) spin echo sequence begins with a:
a. 90° RF pulse
b. 180° RF pulse
c. 45° RF pulse
d. a or b
b. 180° RF pulse
- A typical spin echo (SE) sequence uses pulses:
a. 90°, 90°
b. 90°, 180°
c. 180°, 180°
d. 180°, 90°
b. 90°, 180°
- A typical inversion recovery (IR) spin echo sequence uses pulses:
a. 90°, 180°, 180°
b. 180°, 90°, 180°
c. 5° RF pulse
d. a or b
b. 180°, 90°, 180°
- T2- weighted fluid attenuated inversion recovery (FLAIR) sequences are typically used for the evaluation of:
a. Musculosketal contusions
b. Fat
c. Retro-orbital fat
d. Periventricular white matter disease
d. Periventricular white matter disease
- A typical gradient echo sequence begins with a:
a. 90° RF pulse
b. 180° RF pulse
c. Alpha pulse that varies with desired image contrast
d. Alpha pulse below 10°
c. Alpha pulse that varies with desired image contrast
- Short tau inversion recovery (STIR) sequences are typically used for the evaluation of all of the following EXCEPT:
a. Musculoskeletal contusions
b. Fat suppression
c. Lesions within the retro-orbital fat
d. Fluid (CSF)
d. Fluid (CSF)
- STIR sequences can suppress the signal from all of the following EXCEPT:
a. Fat within bone marrow
b. Gadolinium-enhancing lesions
c. Retro-orbital fat
d. Fluid (CSF)
d. Fluid (CSF)
- To produce the echo, a gradient echo pulse sequence uses a:
a. Gradient magnetic field only
b. RF pulse only
c. Combination of a and b
d. Switching device
e. A combination of any two RF pulses
c. Combination of a and b
- The 180° pulse that follows the initial 90° pulse in a spin echo sequence will cause the NMR signal to reappear while correcting for:
a. Slight magnetic field inhomogeneities
b. Chemical shift
c. Slight magnetic susceptibility effects
d. All of the above
d. All of the above
- The gradient that is on during the production of the echo is called the:
a. Phase encoding gradient
b. Slice select gradient
c. Frequency encoding gradient/ readout
d. Flow encoding gradient
c. Frequency encoding gradient/ readout
- If the TR of a gradient echo pulse sequence is considerably less than the T2 (and T2*), the condition that will exist is known as:
a. Steady state
b. Spin dephasing
c. Spin rephrasing
d. Spin cancellation
a. Steady state
- Phase encoding is performed:
a. After frequency encoding
b. Prior to frequency encoding
c. In place of frequency encoding
d. During frequency encoding
b. Prior to frequency encoding
- The gradient that is on during the production of the echo is the:
a. Phase
b. Slice selection
c. Frequency
d. Oblique
c. Frequency
- The ‘readout’ gradient is also known as the:
a. Phase
b. Slice selection
c. Frequency
d. Oblique
c. Frequency
- If a phase resolution of 256 is desired, then the TR must be repeated (for one NSA):
a. 192 times
b. 256 times
c. 512 times
d. Twice
b. 256 times
- In the multi-echo spin echo sequence shown in Figure C.1 the number of SHORT TE images created with a 20-slice sequence will be:
a. 2
b. 4
c. 20
d. 40
c. 20
FIGURE C.1
- In the multi-echo spin echo sequence shown in Figure C.1, the amount of LONG TE images created with a 20-slice sequence will be:
a. 2
b. 4
c. 20
d. 40
c. 20
FIGURE C.1
- In the multi-echo spin echo sequence in Figure C.1 the number of images PER SLICE LOCATION created will be:
a. 2
b. 4
c. 20
d. 40
a. 2
19.In the multi-echo spin echo sequence in Figure C.1, the TOTAL number of images created with a 20-slice sequence will be:
a. 2
b. 4
c. 20
d. 40
d. 40
- In the multi-echo spine echo sequence shown in Figure C.1, images will be acquired with varying amounts of:
a. T1 information
b. T2 information
c. T2* information
d. Proton density (PD) information
b. T2 information
- If the pulse sequence shown in Figure C.1 were a fast spin echo sequence, the number of lines K space filled during each TR period would be:
a. 4
b. 1
c. 8
d. 2
d. 2
- If a given conventional spin echo pulse sequence takes 12 minutes to acquire, a fast spin echo sequence using an ETL of six, with all other factors that affect scan time remaining the same, will take:
a. 2 minutes
b. 1 minute
c. 6 minutes
d. 4 minutes
a. 2 minutes
- In a fast spin echo sequence, the effective TE is the echo that is performed with the:
a. Outer views of K space
b. High amplitude phase-encoding gradients
c. Low amplitude phase-encoding gradients
d. First phase-encoding steps
c. Low amplitude phase-encoding gradients
- In a fast spin echo sequence, spatial resolution is associated with the:
a. Central lines of K space
b. High amplitude phase-encoding gradients
c. Low amplitude phase-encoding gradients
d. First phase-encoding steps
b. High amplitude phase-encoding gradients
- In a fast spine echo (FSE) sequence, acquired with short effective TE (T1- or PD- weighted images), blurring can be reduce by selection of:
a. Shorter ETL
b. Longer ETL
c. There is no ETL change that affects blurring
d. Larger FOV
a. Shorter ETL
- In a fast spin echo (FSE) sequence, acquired with long effective TE (T2- weighted images), scan time can be reduced by the selection of:
a. Shorter ETL
b. Longer ETL
c. There is no ETL change that affects scan time
d. Larger FOV
b. Longer ETL
- A gradient echo sequence in which any residual transverse magentisation is removed prior o the next excitation pulse is known as:
a. Nonphasic
b. Incoherent/ spoiled
c. Nonresidual
d. Magnetisation prepared
b. Incoherent/ spoiled
- When a gradient echo sequence is acquired for dynamic contrast-enhanced imaging of the liver, ___________ is performed.
a. An additional 180° pulse
b. An initial 180° pulse
c. Spoiling
d. Coherence
c. Spoiling
- Gradient echo sequences acquired for high signal fluid are known as all of the following EXCEPT:
a. Coherent gradient echoes
b. Incoherent gradient echoes
c. Steady-state gradient echoes
d. T2* gradient echoes
b. Incoherent gradient echoes
- Dynamic enhanced MRA sequences of the renal arteries are performed with the use of:
a. Incoherent gradient echoes
b. Coherent gradient echoes
c. Steady-state gradient echoes
d. T2* gradient echoes
a. Incoherent gradient echoes
- Gradient echo sequences can yield either T1 or T2* characteristics.
a. True
b. False
a. True
- Gradient echo sequences can yield either T1 or T2* characteristics, with influences caused by all of the following EXCEPT:
a. Susceptibility
b. Inhomogeneity
c. Chemical shift
d. Aliasing
d. Aliasing
- Gradient echo sequences acquired for the evaluation of hemorrhagic lesions rely on:
a. Susceptibility
b. Inhomogeneity
c. Chemical shift
d. Aliasing
a. Susceptibility
- A FLAIR sequences is utilised to suppress the signal from:
a. MS plaques
b. Gadolinium
c. Fat
d. CSF
d. CSF
- Which of the following field strengths would require the shortest (lowest) T1 time to suppress/ null the signal from fat when acquiring a STIR sequence in an MR exam of the knee?
a. 0.35T
b. 1.0T
c. 1.5T
d. 3.0T
a. 0.35T
- If one desires to null the signal from a specific tissue using an inversion recovery sequence, one should select an inversion time that is _____ of the T1 relaxation time of that tissue.
a. 43%
b. 69%
c. 80%
d. 37%
b. 69%
- Which of the following best describes an EPI sequence?
a. A 90° pulse followed by a 180° pulse
b. A 180° pulse followed by a 90°/180° combination
c. A ‘train’ of gradient echoes
d. A ‘train’ of spin echos
c. A ‘train’ of gradient echoes
- Which of the following best describes an FSE sequence?
a. A 90° pulse followed by a 180° pulse
b. A 180° pulse followed by a 90°/180° combination
c. A ‘train’ of gradient echoes
d. A ‘train’ of spin echos
d. A ‘train’ of spin echos
- Which of the following best describes an IR sequence?
a. A 90° pulse followed by a 180° pulse
b. A 180° pulse followed by a 90°/180° combination
c. A ‘train’ of gradient echoes
d. A ‘train’ of spin echos
b. A 180° pulse followed by a 90°/180° combination
- Which of the following best describes a SE sequence?
a. A 90° pulse followed by a 180° pulse
b. A 180° pulse followed by a 90°/180° combination
c. A ‘train’ of gradient echoes
d. A ‘train’ of spin echos
a. A 90° pulse followed by a 180° pulse
- In which of the following EPI sequences would one expect there to be the least susceptibility (distortion) artefacts?
a. Single-shot SE-EPI, 256 phase x 256 frequency
b. Single-shot GRE-EPI, 512 phase x 192 frequency
c. Multi-shot (4-shot) SE-EPI, 256 phase x 256 frequency
d. Single-shot SE-EPI, 192 phase x 192 frequency
c. Multi-shot (4-shot) SE-EPI, 256 phase x 256 frequency
- When acquiring an fMRI series to map out the visual cortex, which of the following pulse sequences would be utilised in order to maximise sensitivity to the BOLD effect?
a. Spin echo EPI
b. Gradient echo EPI
c. Fast spin echo with driven equilibrium
d. 3D spoiled GRE with TMC
b. Gradient echo EPI
- In which of the following sequences would MS plaques appear hypertintense relative to both CSF and normal white matter?
a. T2 FLAIR
b. T1 FLAIR
c. T2 FSE
d. T2 FSE with RF fat suppression
a. T2 FLAIR
- In a balanced GRE acquisition, the contrast weighting is:
a. T1 weighted
b. T2 weighted
c. T2* weighted
d. Weighted for the ratio of T2/T1
d. Weighted for the ratio of T2/T1
- In an image acquired with a balanced GRE sequencee (Figure C.2), all of the following have high (bright) signal EXCEPT:
a. Blood in the left ventricle
b. CSF
c. IVC
c
d. Weighted for the ratio of T2/T1
- Parallel imaging techniques are also known as all of the following EXCEPT:
a. SENSE
b. SMASH
c. GRAPPA
d. SAT
d. SAT
- When parallel imaging techniques are performed, a low resolution _______ scan is acquired prior to the acquisition:
a. Test bolus
b. Filtering scan
c. Calibration scan
d. Sat pulse
c. Calibration scan
- When doing an MRA of the IVC, a saturation band should be placed ________ to the axial slices.
a. Anterior
b. Posterior
c. Superior
d. Inferior
c. Superior
- When doing an MRA of the carotid arteries, a saturation band should be placed _________ to the axial images.
a. Anterior
b. Posterior
c. Superior
d. Inferior
c. Superior
- When doing an MRA of the circle of Willis, a saturation band should be placed ______ to the axial slices.
a. Anterior
b. Posterior
c. Superior
d. Inferior
c. Superior
- When doing an MRV of the superior sagittal sinus, a saturation band should be placed ______ to the axial images.
a. Anterior
b. Posterior
c. Superior
d. Inferior
d. Inferior
- Scan time for 2D SE pulse sequences can be calculated by:
a. TR x #PEs x NSA
b. TR x #PEs x NSA x #slices
c. TR x #PEs x NSA/ ETL
d. TR x #shots x NSA
a. TR x #PEs x NSA
- Scan time for 2D IR pulse sequences can be calculated by:
a. TR x #PEs x NSA
b. TR x #PEs x NSA x #slices
c. TR x #PEs x NSA/ ETL
d. TR x #shots x NSA
a. TR x #PEs x NSA
- Scan time for 2D GRE pulse sequences can be calculated by:
a. TR x #PEs x NSA
b. TR x #PEs x NSA x #slices
c. TR x #PEs x NSA/ ETL
d. TR x #shots x NSA
a. TR x #PEs x NSA
- Scan time for EPI pulse sequences can be calculated by:
a. TR x #PEs x NSA
b. TR x #PEs x NSA x #slices
c. TR x #PEs x NSA/ ETL
d. TR x #shots x NSA
d. TR x #shots x NSA
- Scan time for 2D FSE pulse sequences can be calculated by:
a. TR x #PEs x NSA
b. TR x #PEs x NSA x #slices
c. TR x #PEs x NSA/ ETL
d. TR x #shots x NSA
c. TR x #PEs x NSA/ ETL
- Scan time for a ‘volume’ acquisition can be calculated by:
a. TR x #PEs x NSA
b. TR x #PEs x NSA x #slices
c. TR x #PEs x NSA/ ETL
d. TR x #shots x NSA
b. TR x #PEs x NSA x #slices
- In a fast spin echo pulse sequence, if the echo trail length is increased by a factor of four, the scan will be:
a. One times as fast
b. Twice as fast
c. Three times as fast
d. Four times as fast
d. Four times as fast
- In a volume acquisition, the scan time is:
a. TR x NSA x BW x thickness
b. TR x NSA x phase encodings x slab thickness
c. TR x NSA x number of phase encodings x ETL
d. TR x NSA x number of phase encodings x number of slices
d. TR x NSA x number of phase encodings x number of slices
- The number of shots is calculated by:
a. TR x #PEs
b. #PEs/ ETL
c. ETL/ #PEs
d. #PEs x NSA
b. #PEs/ ETL
- A single-shot FSE sequence is acquired when:
a. #PEs= 256 and TEL =256
b. #PEs= 128 and ETL= 256
c. #PEs= 256 and ETL= 128
d. #PEs= 256 and ETL= 64
a. #PEs= 256 and ETL =256
- A multi-shot FSE sequence is acquired (with four shots) when:
a. #PEs= 256 and ETL =256
b. #PEs= 128 and ETL= 256
c. #PEs= 256 and ETL= 128
d. #PEs= 256 and ETL= 64
d. #PEs= 256 and ETL= 64
- To keep time at a minimum, diffusion imaging is typically performed with:
a. Single-shot EPI acquisition
b. Single-shot FSE acquisition
c. Multi-shot (two-shot) EPI acquisition
d. Multi-shot (four-shot_ EPI acquisition
a. Single-shot EPI acquisition