Physics: Mri (Sequences)

Front 1

What are 5 different echo types

Back 1

spin echo
gradient echo
hahn echo
stimulated echo

Front 2

What are the 3 main sequence families

Back 2

spin echo sequences, characterized by the presence of a 180° rephasing RF pulse
gradient echo sequences
hybrids

Front 3

Have numerous variations been developed within each of these families, mainly to increase acquisition speed

Back 3

yes

Front 4

What are some variations of spine echo sequences
3

Back 4

fast spin echo
HASTE
single shot FSE

Front 5

What are variations of GRE sequences

Back 5

spoiled gradient echo
ultrafast gradient echo
steady state gradient echo
balanced steady state gradient echo
echoplanar

Front 6

What are 2 examples of hybrid MR sequences

Back 6

GRASE
SE-EPI

Front 7

What does the family tree of MR look like

Back 7

Front 8

What does the family tree of MR look like

Back 8

Front 9

What does the family tree of MR look like

Back 9

Front 10

Are flair and stir types of inversion recovery sequences

Back 10

yes

Front 11

What are the 2 main types of spin echo sequences

Back 11

FSE and inversion recovery

Front 12

Are spin echo sequences always T2

Back 12

yes

Front 13

What are the 4 main groups of GRE sequences

Back 13

balanced steady state
contrast enhanced steady state
steady state GE
spoiled GE

Front 14

Is Ultrafast GE a type of spoiled GE

Back 14

yes

Front 15

Can GE be both T1 or T2 star

Back 15

yes

Front 16

Are multi echo spin echo and spin echo sometimes used interchangeably even though they are totally different

Back 16

yes

Front 17

What are some additional acrynoms for ultra fast SE

Back 17

SSH TSE
SS TSE
SS FSE
FSE - ADA
supper FASE
HASTE

Front 18

Is HASTE a type of ultra fast SE

Back 18

yes

Front 19

What type of SE sequence is HASTE

Back 19

ultra fast SE

Front 20

What is the GE equivalent of HASTE (ultra fast SE)

Back 20

SS-FSE

Front 21

What are some acrymomns for STIR

Back 21

STIR TSE
turbor STIR

Front 22

What is TIRM

Back 22

an inversion recovery sequence

Front 23

What are some acyrnoms of FLAIR

Back 23

FLAIR TSE
Turbo FLAIR
Fast FLAIR

Front 24

What are some acrynomns for GE

Back 24

FFE
FE
GE
GRE

Front 25

What are some acrynomns for ultrafast GE

Back 25

Front 26

What are some acrynomns for spoiled GE

Back 26

Front 27

go back for GE stuff

Back 27

http://www.imaios.com/en/e-Courses/e-MRI/MRI-Sequences/Sequences-acronyms

Front 28

When does the rephasing pulse (180degree) occur in spin echo

Back 28

TE/2

Front 29

How much K-space is filled with each TR in a spin echo sequence

Back 29

With each repetition, a k-space line is filled, thanks to a different phase encoding.

Front 30

Does the 180 degree pulse require a rephasing lobe

Back 30

no

Front 31

What heppens when the TR is really long

Back 31

The longer the TR, the more complete the longitudinal magnetization regrowth (decrease T1).

Front 32

What is aquired after 1 TR r

Back 32

single K space line is filled

Front 33

What happens to the T2 when the TR is long

Back 33

hen the TR is long (over 2000 milliseconds), longitudinal magnetization recovery is complete and on the following flip, the influence of T1 on signal magnitude will be minimized

Front 34

What is a long TE

Back 34

80-140 msec

Front 35

What is the TE/TR timing of a proton density image

Back 35

10-20msec
over 20000msec

Front 36

What happens to the T2 when the TR is long

Back 36

hen the TR is long (over 2000 milliseconds), longitudinal magnetization recovery is complete and on the following flip, the influence of T1 on signal magnitude will be minimized

Front 37

Can Spin echo sequences be used to get T1 images

Back 37

yes, but it is time prohibitive and not used (long TR intervals)

Front 38

What is a long TE

Back 38

80-140 msec

Front 39

What is the TE/TR timing of a proton density image

Back 39

10-20msec
over 20000msec

Front 40

What is the major disadvantatge of spin echo

Back 40

it takes forever

Front 41

Can Spin echo sequences be used to get T1 images

Back 41

yes, but it is time prohibitive and not used (long TR intervals)

Front 42

What is the major disadvantatge of spin echo

Back 42

it takes forever

Front 43

What are 2 types of FSE

Back 43

multi echo SE
Fast SE

Front 44

What is FSE also known as

Back 44

Turbo spin echo

Front 45

Is fse used as a generic term referring to both multi spin echo and FSE (turbo) and is very confusing bc it has the same name as one of the things it is referring

Back 45

yes

Front 46

What is the princible behind FSE

Back 46

In fast spin echo sequences, the interval of time after the first echo, is used to receive the echo train, to fill the other k-space lines in the same slice

Front 47

What are 2 types of FSE

Back 47

multi echo SE
Fast SE

Front 48

Why is FSE so fast

Back 48

Because of the reduced number of repetitions (TR) required, the k-space is filled faster and slice acquisition time is reduced.

Front 49

What is FSE also known as

Back 49

Turbo spin echo

Front 50

What happens to the T2 when the TR is long

Back 50

hen the TR is long (over 2000 milliseconds), longitudinal magnetization recovery is complete and on the following flip, the influence of T1 on signal magnitude will be minimized

Front 51

What is a long TE

Back 51

80-140 msec

Front 52

What is the TE/TR timing of a proton density image

Back 52

10-20msec
over 20000msec

Front 53

Is fse used as a generic term referring to both multi spin echo and FSE (turbo) and is very confusing bc it has the same name as one of the things it is referring

Back 53

yes

Front 54

What is the princible behind FSE

Back 54

In fast spin echo sequences, the interval of time after the first echo, is used to receive the echo train, to fill the other k-space lines in the same slice

Front 55

Can Spin echo sequences be used to get T1 images

Back 55

yes, but it is time prohibitive and not used (long TR intervals)

Front 56

Why is FSE so fast

Back 56

Because of the reduced number of repetitions (TR) required, the k-space is filled faster and slice acquisition time is reduced.

Front 57

What is the major disadvantatge of spin echo

Back 57

it takes forever

Front 58

What is HASTE

Back 58

A variation of the (Half Fourier Acquisition Single Shot Turbo Spin Echo) HASTE sequence, whereat half of the image information is aquired after the first excitation pulse, and the half after the second excitation pulse. The acquired data are then interleaved into the raw data matrix. A long time to repetition (TR) is selected to allow the spin system to recover between excitation pulses and the dead time is used for additional slices. The lenght of the echo train is cut in half. Also more than 2 segments are possible.

Front 59

What does a fast spin echo sequence look like (turbo spin echo)

Back 59

Front 60

When is the GSS always applied

Back 60

simultaneously with the RF pulse

Front 61

What is done after each signal

Back 61

After each echo, the phase-encoding is cancelled and a different phase-encoding is applied to the following echo. (see there are 2 phase encoding symbols per 180 pulse they are in different directions and cancel eachother out)

Front 62

What is the turbo factor or echo train length

Back 62

The number of echoes received in the same repetition (during TR time) is called the Turbo Factor or Echo Train Length (ETL).

Front 63

What is the difference between turbo spin echo and multi echo SE sequences

Back 63

TSE allows multiple K-lines to be filled per TR and MSE allows several images of the same slice position to be obtained with different contrast

Front 64

When is the second 180 degree RF pulse done in a MSE

Back 64

After the first echo is obtained, there is a free interval until the next TR. By applying a new 180° pulse, a new echo is received, with the same phase encoding, to build the second image

Front 65

What is the difference between the first and second echo signal

Back 65

The echo time of the 2 images differs and the second image will be more T2 weighted than the first

Front 66

What is the MSE sequence typically used for

Back 66

ypically, these sequences are used to obtain simultaneously PD- and T2-weighted images.

Front 67

What does MSE look like

Back 67

Front 68

Why does MSE have a different number of phase encoding symbols

Back 68

because it is imaging the same row over and over