Special Procedures Flashcards
Which of the following is a method of visualizing vessels containing flowing nuclei by creating contrast between flowing spins and stationary tissue?
A. MRA
B. Dixon technique
C. Spectroscopy
D. Turbulent flow
A. MRA
MRA techniques can be used to visualize both arteries and veins.
True or false
True
What type of blood flow is also referred to as first order motion?
A. Spiral/vortex flow
B. Turbulent flow
C. All answers are correct
D. Laminar flow
D. Laminar flow
What type of blood flow can be compensated for by the MR system?
A. Spiral/vortex flow
B. Turbulent flow
C. No answers are correct
D. Laminar flow
D. Laminar flow
What type of blood flow is also referred to as third order motion?
A. Spiral/vortex flow
B. Turbulent flow
C. Laminar flow
D. Both turbulent and laminar flow
B. Turbulent flow
Where does the velocity of blood flow tend to be the greatest?
A. Near the periphery of a blood vessel
B. Near the center of a blood vessel
C. Within the extracellular spaces
D. Within the blood vessels with a larger diameter
B. Near the center of a blood vessel
Which of the following is considered a flow from phenomenon?
A. Time of flight
B. Entry slice phenomenon
C. Intra-voxel dephasing
D. All answers are correct
D. All answers are correct
What flow phenomenon describes? How stationary spins return more signal than flow and spins since they are more likely to receive both an excitation and rephasing pulse before traveling out of a slice?
A. Time of flight
B. Entry slice phenomenon
C. Intra-voxel dephasing
D. Laminar flow
A. Time of flight
TOF phenomenon is observable during GE pulse sequences.
True or false
False
TOF phenomenon is not observable during GE pulse sequences because the rephasing gradient used is not slice selective.
True or false
True
As flow velocity________,
TOF effects_______.
A. Decreases/ increase
B. No answers are correct
C. Increases/ increase
D. Increases/ decrease
C. Increases/ increase
As TOF effects increase, the signal received from flowing nuclei _______
A. Increases
B. Decreases
C. Stays the same
D. Increases in multiples of 2
B. Decreases
What phrase describes the signal lost due to TOF affects as velocity of flow increases?
A. High velocity signal loss
B. Flow related enhancement
C. Velocity amplification
D. Flow gain
A. High velocity signal loss
What phrase describes the signal lost due to tof affects as velocity of flow decreases?
A. High velocity signal loss
B. Flow related enhancement
C. Velocity amplification
D. Flow gain
B. Flow related enhancement
Why is flowing blood sometimes hyperintense to stationary tissue during TOF sequences?
A. Because of high velocity signal loss
B. Because of flow-related enhancement
C. Because of the increased temperature of flowing blood
D. All answers are correct
B. Because of flow-related enhancement
Why is flowing blood sometimes hypointense to stationary tissue during TOF sequences?
A. Because of high velocity signal loss
B. Because of flow-related enhancement
C. Because of the increased temperature of flowing blood
D. All answers are correct
A. Because of high velocity signal loss
As flow velocity decreases, less flowing nuclei are present within a slice for both the excitation and rephrasing pulses.
True or false
False
As the TE________, TOF effects_________
A. Increases/ increase
B. Increases/decrease
C. Decreases/ increase
D. No answers are correct
A. Increases/ increase
As the TE________, TOF effects_________
A. Decreases/ decrease
B. Increases/decrease
C. Decreases/ increase
D. No answers are correct
A. Decreases/ decrease
As the TE decreases, less flowing nuclei are present within a slice for both the excitation and rephrasing pulses.
True or false
False
As slice thickness decreases, TOF effects_______
A. Increase
B. Decrease
C. Stay the same
D. Disappear
A. Increase
One advantage of 3D TOF over 2D TOF is:
A. The ability to visualize larger vessels
B. The ability to visualize smaller vessels.
C. Decreased spatial resolution
D. Improved magnetic field homogeneity
B. The ability to visualize smaller vessels.
What flow phenomenon explains how signal intensity is affected by the direction of flowing nuclei in relation to a stack of slices?
A. Time of flight
B. Entry slice phenomenon
C. Intravoxel dephasing
D. Laminar flow
B. Entry slice phenomenon
Which term is synonymous with entry/ phenomenon?
A. Outflow effect
B. Inflow effect
C. Intra-voxel dephasing
D. Time of flight
B. Inflow effect