quality control Flashcards
If the slice thickness is reduced by a factor of 2, the factor by which the NSA must be increased
A) 8
B) 1.41
C) 4
D) 2
c. SNR√NSA √4=2
if the slice thickness is increased by a factor of 2 the SNR
A) increase √2
B) increase by a factor of 2
C) reduce by a factor of 2
D) reduce by a factor √2
b
if the slice thickness increases, the spatial resolution
A) increases
B) decreases
C) stays the same
D) not effected
b
if the slice thickness increases, the SNR
A) increases
B) decreases
C) stays the same
D) not effected
a
changing the voxel size in the ƒ direction will
A) double the scan time
B) decrease the scan time
C) have no effect on the scan time
D) increase the scan time by 0.5
c
factors that effect contrast to noise ratio include all of the following except
A) TR
B) TE
C) TI
D) flip angle
E) matrix
e
SNR is a factor that is measured
A) true
B) false
a
CNR is a factor that is measured
A) true
B) false
b
factors that effect the spatial resolution include all of the following except
A) FOV
B) slice thickness
C) flip angle
D) matrix
c
factors that effect SNR include all of the following except
A) TR
B) field strength
C) FOV
D) matrix
E) hour of the day
e
centre frequency is a factor that determines the
A) ƒ of RF used for excitation
B) ƒ of RF used for signal detection
C) a and b
D) amplitude or duration of the RF pulse
c
transmit gain is a factor that determines the
A) ƒ of RF used for excitation
B) ƒ of RF used for signal detection
C) a and b
D) amplitude or duration of the RF pulse
d
geometric accuracy is determined by the
A) RF system
B) shim system
C) gradient system
D) main magnet system
c
During MR imaging, all equipment should be inspected prior to use to make sure all components are in worker order, these include
A) RF coils and cables
B) RF coils and door seals
C) cables and door seals
D) quench system
E) all of the above
e
reducing the slice thickness by a factor of 2 will reduce the SNR by
A) 2
B) 1.41
C) 2.5
D) 1.5
a
