問題一覧
1
repeated n times using a repetition time interval of TR to obtain phase-encoding.
Pulse Sequence
2
Heart of MRI
Pulse Sequence
3
controls the transmission of the RF which then create a measurable signal from a selected slice.
pulse sequence
4
Series of RF pulses
pulse sequence
5
signal is strong, the image shows
bright pixels
6
weaker signals result in
dark pixel
7
Image of Raw Data
kspace
8
Phase encoding
y axis
9
Frequency encoding
x axis
10
Slice selection
z axis
11
Y direction n (phase encoding)
128-256
12
X direction n (frequency encoding)
256
13
Most basic pulse sequence in mri
spin echo
14
Pulse of spin echo
90-180
15
Time consuming sequence
spin echo
16
Mr scanner can only detect signal in what plane
transverse
17
Signal depends on
t2*
18
Consist pf single 180 pulse
single spin echo
19
Use to produce t1 short tr and short te
single spin echo
20
How many 180 pulse are there in dual spin echo
2
21
Used to produce t2 and proton density
dual spin echo
22
Long tr long te
t2
23
Proton density
long tr short te
24
Used to make se much faster
fast spin echo
25
90-180-180-180-180
fast spin echo
26
180-90 pulse
inversion recovery
27
Turns longitudinal magnetization to opposite direction
irs
28
Inversion recovery major sequence
STIR, FLAIR
29
Short tIs (100-180ms)
stir
30
Nulls signal from fat
stir
31
Mainly use in muskuloskeletal
stir
32
Tis 1700-2200
flair
33
Nulls signal from csf
flair
34
Mainly use in cns
flair
35
Water signal ms
2000-2400
36
Oldest imaging sequence
gre
37
Absent 180 pulse
gre
38
Use in angiogram/ contrast flow procedure
gre
39
Rf pulse infinite
epi
40
Single tr in kspace
epi
41
Epi ms
50-100
42
Gives good dynamic protocol
epi
43
Minimize effect of px motion
epi
44
Imaging small anatomy (knees)
3d imaging
45
Orthogonal phase encoding + frequency phase encoding
3d imaging
46
Xnxn, x?
orthogonal