SCAN TIME Flashcards
Does scan time depend on
A) TR
B)TE
A) TR
Does scan time depend on
A) # phase encodings
B) # of frequency encodings
A) # of phase encodings
Does scan time depend on
A) flip angle
B) Number of NSA’s
B) Number of NSA’s
Does scan time depend on
A) frequency encoding FOV
B) # of slices in 3D imaging
B) # of slices in 3D imaging
Does scan time depend on
A) ETL in FSE
B) readout gradient
A) ETL in FSE
Does scan time depend on
A) readout gradient
B) # of shots in EPI
B) # of shots in EPI
Scan time = TR x #PE x NSA
2D SE
Scan time = TR x #PE x NSA x # slices
3D imaging
Scan time = TR x #PE x NSA / ETL
FSE
Scan time = TR x NSA x # shots
Increase TR
increase SNR
increase # of slices
increase TR
increase scan time
decrease T1 weighting
scan time for a 2D SE pulse sequence 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
when performing a 2D IR pulse sequence the time 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
scan time for 2D GE 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
scan time for EPI 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
scan time for 2D FSE 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
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
in a FSE pulse sequence, if the ETL is increased by a factor of 4 the scan will be
A) 1x as fast
B) 2x as fast
C) 3x as fast
D) 4x as fast
d
in a volume acquisition the scan time is
A) TR x NSA x BW x thickness
B) TR x NSA x PEs x slab thickness
C) TR x NSA x PEs x ETL
D) TR x NSA x PE’s x # of slices
d
number of shots is calculated by
A) TR x PEs
B) #PEs/ETL
C) ETL/#PE’s
D) #PEs x NSA
b
a single shot FSE sequence is acquired when
A) #PEs=256, ETL=256
B) #PEs= 128, ETL= 256
C) #PEs= 256, ETL= 128
D) #PE’s = 256, ETL= 64
a
a multi-shot FSE sequence is acquired with 4 shots when
A) #PEs=256, ETL= 256
B) #PEs=128, ETL= 256
C) #PEs= 256, ETL= 128
D) #PEs= 256, ETL= 64
d
to keep scan time to a minimum, diffusion imaging is usually performed with
A) single shot EPI
B) single shot FSE
C) 2 shot EPI
D) 4 shot EPI
a
