Pulse Sequences

Question 1

an inversion recovery spin echo sequence begins with a

Answer 1

180 RF pulse

Question 2

a typical SE sequence uses pulses

Answer 2

90, 180

Question 3

a typinca inversion recovery spn echo sequence uses pulses

Answer 3

180, 90, 180

Question 4

T2 weighted fluid attenuated inversion recovery (FLAIR) sequences are typically used for the evaluation of

Answer 4

periventricular white matter disease

Question 5

typical gradient echo sequence begins with a

Answer 5

alpha pulse that varies with desired image contrast

Question 6

short tau inversion recovery (STIR) sequences are typically used for the evaluation of all of the following

Answer 6

musculoskeletal contusoins

fat suppression

lesions within the retro orbital fat

Question 7

STIR sequences can supress the signal from all of the following

Answer 7

fat within bone marrow

gadolinium enhancing lesions

retro orbital fat

Question 8

to produce the echo a gradient echo pulse sequence uses a

Answer 8

gradient magnetic firled

RF pulse

Question 9

the 180 pulse taht follows the initial 90 pulse in a spin echo sequence will cause the NMR signal to reappear while correcting for

Answer 9

slight magnetic field inhomogenieties

chimical shift

slight magnetic susceptibility effects

Question 10

the gradient that is on during the production of the echo is called the

Answer 10

frequency encoding gradient

readout gradient

Question 11

if the TR of a gradient echo pulse sequence is considerably less than the T2 (and T2*) the condition that will exist is known as

Answer 11

steady state

Question 12

phase encoding is performed

Answer 12

prior to frequency encoding

Question 13

the gradient taht is on during the production of the echo is the

Answer 13

frequency

Question 14

the readout gradient is also known as the

Answer 14

frequency gradient

Question 15

if a phase resolution of 256 is desired, then the TR must be repeated (for one NSA)

Answer 15

256 times

Question 16

in the multi echo spin echo sequence shown in figure C 1, the number of SHORT TE images created with a 20 slice sequence will be

Answer 16

20

Question 17

in the multi echo spin echo sequence shown in figure C 1, the number of LONG TE images created with a 20 slice sequence will be

Answer 17

20

Question 18

in the multi echo spin echo sequence shown in figure C 1 the number of images PER SLICE LOCATION created will be

Answer 18

2

Question 19

in the multi echo spin echo sequence shown in figure C 1 the TOTAL number of images wiht a 20 clice sequence will be

Answer 19

40

Question 20

in the multi echo spin echo sequence shown in figure C 1 images will be acquired with varying amounts of

Answer 20

T2 information

Question 21

if the pulse sequence shown in figure C 1 were a fast spin echo sequence the number of lines of K space filled during each TR period would be

Answer 21

2

Question 22

if a given conventional spin echo sequence takes 12 minutes to acquire a fast spin echo sequence using an ETL of 6 with all other factors that affect scan time remaining the same, will take

Answer 22

2 minutes

Question 23

in a FSE sequence the effective TE is the echo that is perfomred with the

Answer 23

low amplitude phae encoding gradients

Question 24

in a FSE sequence spatial resolution is associated with the

Answer 24

high amplitude phase encoding gradients

Question 25

in a FSE sequence acquired with a short effective TE, (T1 or PD weighted images) blurring can be reduced by the selection of

Answer 25

shorter ETL

Question 26

in a FSE sequence acqwuired with a long effective TE (T2 images) scan time can be reduced by the selection of

Answer 26

longer ETL

Question 27

a gradient echo sequence in which any residual transverse magnetization is removed prior to the next excitation pulse is known as

Answer 27

incoherent/spoiled

Question 28

when a gradient echo sequence is acquired for dynamic contrast enhanced imaging of the liver _________is performed

Answer 28

spoiling

Question 29

gradient echo sequences acquired for high signal from fluid are known as all of the following

Answer 29

coherent gradient echoes

steady state gradietn echoes

T2* gradietn echoes

Question 30

dynamic enhanced MRA sequences of the renal arteries are performed with the use of

Answer 30

incoherent gradient echoes

Question 31

gradient echo sequences can yeild either T1 or T2* characteristics

true/false

Answer 31

true

Question 32

gradient echo sequences can yeild either T1 or T2* characteristics with influencs cause by all of the followng

Answer 32

susceptibility

inhomongeniety

chemical shift

Question 33

gradient echo sequences acquired for the evaluation of hemorrhagic lesions rely on

Answer 33

susceptibility

Question 34

sequence is utilized to supress the signal from fluid

Answer 34

FLAIR

Question 35

which of the following field strenghts would require the shortest (lowest) T1 time to supress/null the signal from fat when acquiring a STIR sequence in an MR exam of the knee

Answer 35

0.35 T

Question 36

if one desires to null the signal from a specific tissue using an inversino recovery sequence, one should select an inversion time that is______of the T1 relaxation tim eof that tissue

Answer 36

69%

Question 37

which of the followoing best describes an EPI sequence

Answer 37

a train of gradient echoes

Question 38

which of the following best describes a FSE sequence

Answer 38

a train of spin echoes

Question 39

which of the folloiwng best describes an IR sequence

Answer 39

180 pulse followed by a 90/180 combination

Question 40

which of the following best describes an SE sequence

Answer 40

90 pulse followed by a 180

Question 41

in which of the following EPI sequences would one expect there to be the least susceptibility distortion artifacts

Answer 41

multishot (4shot) SE-EPI, 256x256 matrix

Question 42

when acquireing an fMRI series to map out the visual cortex which of the followoing sequences would be utilized in order to maximize sensitivity to the BOLD effect

Answer 42

gradient echo EPI

Question 43

in which of the folloiwng sequences would MS plaques appear hyperintense relative to both CSF and normal white matter

Answer 43

T2 FLAIR

Question 44

in a balanced GRE acquisition the contrast weighting is

Answer 44

weighted for the ratio of T2/T1

Question 45

in an image acquired with a blamace GRE sequence (fig C 2) all of the following have high (bright) signal

Answer 45

blood in the left ventricle

CSF

IVC

Question 46

parallel imaging techniques are also known as all of the follwoing

Answer 46

SENSE

SMASH

GRAPPA

Question 47

when parallel imaging techniques are performed a low resolution ______scan is acqiured pror to the acquisition

Answer 47

calibration

Question 48

when doing an MRA of the IVC a saturation band should be placed _________to the axial slices

Answer 48

superior

Question 49

when doing an MRA of the carotid arteries a saturation band should be places _______to the axial slices

Answer 49

superior

Question 50

when doing an MRA of the circle of willis, a saturation band should be placed _____to the axial slices

Answer 50

superior

Question 51

when doing an MRA of the superior sagittal sinus a saturation band should be places ______to the axial slices

Answer 51

inferior

Question 52

scan time for 2D IR pulse sequences can be calculated by

Answer 52

TR x #PEs x NSA

Question 53

scan time for 2D GRE pulse sequences can be calculated by

Answer 53

TR x #PEs x NSA

Question 54

scan time for EPI pulse sequences can be calculated by

Answer 54

TR x #shots x NSA

Question 55

scan time for 2D FSE puilse sequences can be calculated by

Answer 55

TR x #PEs X NSA/ETL

Question 56

scan time for a volume acquisition can be calculated by

Answer 56

TR x #PEs x NSA x #slices

Question 57

in a FSE sequence if the echo trail length is increased by a factor of rour, the scan will be

Answer 57

four times as fast

Question 58

in a volume acquisition the scan time is

Answer 58

TR x NSA X number of phase encodings X number of slices

Question 59

the number of shots is calculated by

Answer 59

PEs/ETL

Question 60

a signle shot FSE sequence is acquired when

Answer 60

PEs = 256 and ETL =256

Question 61

a multi shot FSE sequence is acquired with four shots shen

Answer 61

PEs =256 and ETL = 64

Question 62

to keep a scan time a minimum diffusion imaging is typically performed with

Answer 62

single shot EPI acquisition