CHAPTER 2

Question 1

Recovery of longitudinal magnetization is called?

Answer 1

T1 Recovery

Question 2

Decay of coherent transverse magnetization is called?

Answer 2

T2 Decay

Question 3

Primary relaxation process?

Answer 3

T1 Recovery

Question 4

Is T1 recovery slower or faster than T2 decay?

Answer 4

Slower

Question 5

Spin-lattice recovery?

Answer 5

T1 Recovery

Question 6

Time it takes for 63% of the longitudinal magnetization to recover in a tissue

Answer 6

T1 Recovery time

Question 7

What kind of recovery happens during TR

Answer 7

T1 Recovery

Question 8

Caused by the magnetic fields of the neighboring hydrogen nuclei interacting with each other

Answer 8

T2 Decay

Question 9

Spin-spin relaxation process?

Answer 9

T2 Decay

Question 10

Secondary relaxation process?

Answer 10

T2 Decay

Question 11

Caused by inhomogeneties in B0

Answer 11

T2 Decay

Question 12

Time it takes for 63% of the transverse magnetization to dephase

Answer 12

T2 Decay time

Question 13

Type of relaxation that results in 37% of inphase left in a tissue

Answer 13

T2 Decay time

Question 14

What determines how much decay happens?

Answer 14

TE

Question 15

Made up of large molecules that are closely packed together and tumbling is slow

Answer 15

fat

Question 16

Made of up molecules that are spaced apart and tumbling rate is fast

Answer 16

water

Question 17

T1 Recovery in fat

Answer 17

short

Question 18

T1 recovery in water

Answer 18

fast

Question 19

T2 decay in fat

Answer 19

short

Question 20

T2 decay in water

Answer 20

fast

Question 21

T1 contrast is controlled by

Answer 21

TR

Question 22

TR must be short or long in T1 contrast so vectors don’t fully recover

Answer 22

short

Question 23

In T1 contrast, fat is… high/low signal & hyper/hypo intense on image?

Answer 23

High signal, hyperintense

Question 24

In T1 contrast, water is… high/low signal & hyper/hypo intense on image?

Answer 24

low signal, hypointense

Question 25

T1 contrast = short/long TR and short/long TE?

Answer 25

short TR, short TE

Question 26

T1 contrast makes what kind of scans?

Answer 26

Anatomy scans & pathology with contrast

Question 27

T2 contrast is controlled by what

Answer 27

TE

Question 28

What must be long to allow protons to have time to dephase to create more differences in contrast

Answer 28

TE - T2 contrast

Question 29

In T2 contrast, fat is... high/low signal & hyper/hypo intense on image?

Answer 29

low signal, hypointense

Question 30

In T2 contrast, water is... high/low signal & hyper/hypo intense on image?

Answer 30

high signal, hyperintense

Question 31

What controls amount of T2 contrast?

Answer 31

TE

Question 32

T2 contrast = short/long TR, short/long TE

Answer 32

long TR, long TE

Question 33

What kind of scans are T2 contrast scans?

Answer 33

Pathology

Question 34

NMV pushed beyond 90deg is?

Answer 34

Partially saturated

Question 35

NMV pushed to a fully 180deg is?

Answer 35

Fully saturated

Question 36

What is differences in mobile hydrogen nuclei per unit volume of tissue?

Answer 36

Proton density

Question 37

What component reflects the differences in proton density contrast?

Answer 37

Transverse

Question 38

Tissues with high proton density have low/high signal and hypo/hyperintense?

Answer 38

High signal, hyperintense

Question 39

What tissues have high proton density in PD scans?

Answer 39

CSF, infection, inflammation, fat

Question 40

Tissues with low proton density have low/high signal and hypo/hyperintense?

Answer 40

Low signal, hypointense

Question 41

What tissues have low proton density in PD scans?

Answer 41

Air, tendons, bone

Question 42

What must be suppressed to see PD contrast?

Answer 42

T1 and T2 contrast

Question 43

What type of scans does PD show?

Answer 43

Anatomy and Pathology

Question 44

PD contrast = short/long TR, short/long TE

Answer 44

long TR, short TE long TR allows vectors to fully recover minimizing T1 and short TE doesn't give vectors enough time to dephase diminishing T2

Question 45

What's the movement of molecules in the extracellular space due to random thermal motion?

Answer 45

diffusion

Question 46

The net displacement of molecules diffusing across an area of tissues per second

Answer 46

ADC - apparent diffusion coefficent

Question 47

Areas of restricted diffusion because the extracellular space is small (ligaments & pathology) the ADC is low/high?

Answer 47

Low

Question 48

Areas of free diffusion extracellular space is large (normal grey matter & normal liver tissue) the ADC is low/high?

Answer 48

High

Question 49

Diffusion weighted images (DWI) are made using what?

Answer 49

Bipolar gradients (dephases and then rephases)

Question 50

Normal tissues have a low/high ADC?

Answer 50

high

Question 51

Low ADC = low/high signal

Answer 51

high signal = pathology

Question 52

Controls how much a tissue's intrinsic contrast parameter contributes towards image weighting

Answer 52

B value

Question 53

Higher b values = less/more diffusion weighting

Answer 53

more

Question 54

What type of sequence is used for DWI?

Answer 54

Spin-echo

Question 55

ADC is intrinsic/extrinsic and b value is intrinsic/extrinsic?

Answer 55

intrinsic & extrinsic

Question 56

Acquires images of brain during activity and at rest

Answer 56

function MRI, fMRI

Question 57

fMRI contrast depends on what type of technique?

Answer 57

BOLD, Blood oxygenation level dependent

Question 58

What exploits the differences of magnetic susceptibility of oxyhemoglobin and deoxyhemoglobin?

Answer 58

BOLD

Question 59

In fMRI, rest images are subtracted from activity images (NO answer)

Question 60

In fMRI, there is a long TR/TE while task is off and on?

Answer 60

TE

Question 61

What uses the fast exchange of energy between bound and free nuclei?

Answer 61

MTC - Magnetization transfer contrast

Question 62

In MTC, free nuclei are observable b/c they have longer what times?

Answer 62

T2 decay

Question 63

In MTC, bound nuclei are restricted b/c they have a very short what time?

Answer 63

T2 decay

Question 64

What uses the magnetic susceptibility differences between tissues to generate contrast?

Answer 64

Susceptibility weighting - SWI

Question 65

What type of sequences are used to enhance the differences in magnetic susceptibility between tissues?

Answer 65

Gradient echo with a long TE

Question 66

What is used to selectively change the relaxation times of certain tissues?

Answer 66

Contrast agents

Question 67

Agents are not imaged themselves but are seen because they indirectly affect the relaxation times of what?

Answer 67

Water nuclei

Question 67

T1 contrast agents = shorten/long T1 recovery times

Answer 67

shorten

Question 68

T2 contrast agents = shorten/long T2 decay times

Answer 68

shorten

Question 69

Degree of contrast shortening due to contrast agents depends on what of the agent?

Answer 69

concentration

Question 70

What is a rare-earth metal and is toxic? Binding or chelation with other molecules such as DTPA makes it safe?

Answer 70

Gadolinium

Question 71

Gadolinium is what and has a large magnetic moment?

Answer 71

Paramagnetic

Question 72

T2 contrast agents are made up of what?

Answer 72

Superparamagnetic macromolecules of iron