Part C: Special procedures Flashcards
- Normal blood flow (demonstrated by a parabolic blood flow profile) is known as:
a. Laminar flow
b. Accelerated flow
c. Vortex flow
d. Turbulent flow
a. Laminar flow
- Blood flow at the area of stenosis (vascular narrowing) is known as:
a. Laminar flow
b. Accelerated flow
c. Vortex flow
d. Turbulent flow
b. Accelerated flow
- The swirling blood flow that occurs just past the area of a stenosis is known as:
a. Laminar flow
b. Accelerated flow
c. Vortex flow
d. Turbulent flow
c. Vortex flow
- Normal blood flow is known as:
a. Laminar flow
b. Accelerated flow
c. Vortex flow
d. Turbulent flow
d. Turbulent flow
- A major advantage of MRA over conventional angiography is that:
a. Images with both heavy T1 and T2 weighting can be produced
b. Multiple views can be produced from a single acquisition
c. Much smaller catheters are used
d. Less ionising radiation is used
b. Multiple views can be produced from a single acquisition
- The MRA sequence that is leas sensitive to slow flow is:
a. 3D phase contrast MRA (PC MRA)
b. 3D time of flight (TOF)
c. 2D PC
d. 2D TOF
b. 3D time of flight (TOF)
- The MRA sequence that is most sensitive to smaller vessels is:
a. 3D phase contrast MRA (PC MRA)
b. 3D time of flight (TOF)
c. 2D PC
d. 2D TOF
b. 3D time of flight (TOF)
- The MRA sequence that is sensitive to flow direction is:
a. 3D phase contrast MRA (PC MRA)
b. 3D time of flight (TOF)
c. 2D TOF
d. Multislice vascular
a. 3D phase contrast MRA (PC MRA)
- The MRA sequence that can be made sensitive to any flow velocity is:
a. 3D phase contrast MRA (PC MRA)
b. 3D time of flight (TOF)
c. 2D TOF
d. Multislice vascular
a. 3D phase contrast MRA (PC MRA)
- The signal intensity on TOF MRA sequences is related to:
a. Gadolinium
b. Flow-related enhancement
c. Velocity- induced phase shift
d. Restricted diffusion
b. Flow-related enhancement
- The signal intensity on PC MRA sequences is related to:
a. Gadolinium
b. Flow-related enhancement
c. Velocity- induced phase shift
d. Restricted diffusion
c. Velocity- induced phase shift
- The signal intensity on diffusion sequences is related to:
a. Gadolinium
b. Flow-related enhancement
c. Velocity- induced phase shift
d. Amount of diffusion
d. Amount of diffusion
- The removal of signal from vessels is an MRA sequence is achieved by:
a. Gradient moment nulling
b. Spatial presaturation
c. Spectral presaturation
d. a and b
b. Spatial presaturation
- The following is (are) important in MRA sequences to minimise the loss of signal due to dephasing within a voxel:
a. Long TR
b. Small voxels
c. Short TE
d. b and c
d. b and c
- Blood flow velocities are greatest:
a. Further away from the heart
b. At a vessel wall
c. At the center of a vessel
d. In a 3D time of flight sequence
c. At the center of a vessel
- Single-order gradient moment nulling does not compensate for:
a. Accelerated flow
b. Reverse flow
c. Constant velocity flow
d. a and b
d. a and b
- In a spin echo sequence, flowing blood is normally seen as a signal void because the:
a. TE is too long to image flow
b. Repetition times used in spin echo sequences are too long to image flow
c. 90° pulse and 180° pulse are both slice selective
d. Flip angle is always 90°
e. a and c
e. a and c
- In a vessel with a plaque producing a high degree of stenosis, the velocity of the blood flow in the center point of the stenosis is:
a. Increased
b. Decreased
c. Reversed
d. Unaffected
a. Increased
- In a time of flight sequence, the tissue is HYPOintense relative to flowing blood because of the:
a. T2 effects
b. T2* effects
c. Saturation effects
d. Inhomogeneities
c. Saturation effects
- In a time of flight sequence, flowing blood is HYPERintense relative to stationary tissue because of the:
a. T2 effects
b. Coil being used
c. Saturation pulse used
d. Flow-related enhancement
d. Flow-related enhancement
- Phase-contrast techniques produce images in which the signal intensity within the vessel is dependent on (among other parameters) the:
a. Velocity of the flowing blood
b. T1 of the tissue
c. FOV selected
d. Number of phase-encoding views
a. Velocity of the flowing blood
- In a phase-contrast technique, it is possible to use the data to determine the:
a. Exact size of the vessel lumen
b. Direction of blood flow
c. Temporal displacement of the vessel
d. Percentage stenosis of a lesion
b. Direction of blood flow
- A major advantage of 3D time of flight techniques over 2D time of flight is the ability to:
a. Determine blood flow velocities
b. Shorten imaging time
c. Visualise smaller vessels
d. Reduce the signal intensity from stationary tissue
c. Visualise smaller vessels
- A major advantage of a 2D time of flight sequence over a 3D time of flight sequence is the ability to:
a. Image a larger area without saturation of the flowing blood
b. Determine the percentage stenosis in the presence of a lesion
c. Better image reverse flow
d. Image a clot without showing he shower flow around it
a. Image a larger area without saturation of the flowing blood
- Cardiac sine acquisitions typically utilise:
a. An inversion recovery pulse sequence
b. A spin echo pule sequence
c. A gradient echo pulse
d. A fast spin echo pulse sequence
c. A gradient echo pulse
- Each ‘frame’ of a cardiac cine sequence displays the heart:
a. In various imaging planes
b. With varying degrees of spatial resolution
c. From slightly different viewpoint
d. In different phases of the cardiac cycle
d. In different phases of the cardiac cycle
- Cine (kinematic) studies are often performed on various joints. The main purpose of such a study is to:
a. Visualise motion and function
b. Visualise blood flow
c. Measure muscle strength
d. Impress referring physicians
a. Visualise motion and function
- Which of the following would result in an image with the greatest amount of diffusion-weighting?
a. b- value 750
b. b- value 450
c. b- value 825
d. b- value 1100
d. b- value 1100
- The main purpose of producing/ calculating an ADC map (image) is to:
a. Reduce the contribution from diffusion effects
b. Eliminate the T2 shine-through
c. Increase SNR
d. Reduce T1 weighting
b. Eliminate the T2 shine-through
- Changing the b-value alters the:
a. Amplitude, timing, and/or duration of the diffusion gradients
b. Amplitude of the phase-encoding gradient
c. Length of the readout gradient
d. Spatial resolution
a. Amplitude, timing, and/or duration of the diffusion gradients
- When performing a dynamic perfusion exam of the brain utilising a gadolinium-based MR contrast agent, the result of the T2* shortening is:
a. Increase MR signal
b. Reduced MR signal
c. Increased acquisition time
d. Increased chemical shift artifact
b. Reduced MR signal
- The basic MR principle with regard to MR spectroscopy is:
a. Faraday’s law of induction
b. Chemical shift
c. Flow-related enhancement
d. The BOLD effect
b. Chemical shift
- Having acquired a 3D TOF, when producing an MRA projection image set using the MIP technique, which of the following can appear bright and therefore the same as flow within a vessel?
a. Tissues with long T2-relaxation times
b. Tissues or substances with extremely short 1-relaxtion times
c. Polycystic astrocytoma
d. Any substance with an extremely short T2-relaxation time
b. Tissues or substances with extremely short 1-relaxtion times
- The intrinsic contrast mechanism with regard of fMRI is:
a. Faraday’s law of induction
b. Chemical shift
c. Flow-related enhancement
d. The BOLD effect
d. The BOLD effect
- All of the techniques below can be utilised to optimally start of a contrast-enhanced MRA EXCEPT:
a. Automated bolus detection
b. Test bolus
c. Centric k-space filling
d. Real-time/ fluoro triggering
c. Centric k-space filling
- In order to reconstruct an image acquired using parallel imaging, which of the following may be required?
a. Test bolus
b. Reference or calibration scan
c. Back projection
d. Half-Fourier acquisition
b. Reference or calibration scan
- When using parallel imaging to reduce acquisition times, which of the following is always true?
a. Scan time is reduced and spatial resolution is increased
b. Spatial resolution is reduced the greater the acceleration factor selected
c. SNR is not affected unless the acceleration factor is greater than 2
d. SNR is reduced and spatial resolution is unaffected
d. SNR is reduced and spatial resolution is unaffected