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Flashcards in Brain Imaging Lec10 Deck (60):
1

____ imaging invovles a rotating x ray beam

CT

2

rate of attenuation with a CT varies by

tissue

Beam attenuates (ie weakens) as it passes through brain tissue

3

what is detected with a CT?

radiodensity information

used to reconstruct 3d image

4

advantages to CT

bone imaging

hemorrhage detection

patient flexibility

5

disadvantages to CT

1. ionizing radiation

2. not as good for soft tissue

3. lower spatial resolution

6

with MRI, Rapid repetitions of ___ enhance gray-white contrast

RF pulse 

7

with MRI,  Infrequent RF pulses enhance___

 water signal

8

advantages to MRI

1. high spatial resolution

2. no radiation

3. excellent contrast

4. functional/chemical imaing avail.

9

disadvantages to MRI

1. long study duration

2. no ferromagnetic or electronic devices

3. small as hell -- claustrophobia

10

with Magnetic resosnance spectroscopy you look at the

chemical structure of the brain

11

on MRS choline indicates

demyelination

12

on MRS, creatine indciates

glial

13

on MRS, lactate indicates

ischemia

14

on MRS, NAA indicates

neuronal marker

15

____ involves measuring water diffusion

DTI: Diffusion Tensor Imaging

16

DTI: Diffusion Tensor Imaging invovles measuring water diffusion along different orientatations within ___

axes

17

fMRI in vivo measures 

BOLD, blood-oxygen-level dependent, signals at baseline vs.
! experimental conditions

18

limitations of FMRI includes

spatial and temporal resolution

19

what does PET involves?

PET: radioactive tracer incorporated into a biologically active molecule (ex. Glucose, oxygen, dopamine transporters)

20

disadvantages of PET? 

 1. need a cyclotron to make radioisotope

2. radiation exposure

21

what are 5 applications of imaging mdoalities?

1. map nml brain development

2. alzheimers disease

3. image guieded neurosurgery

4. schizopehnia

5. pain )in high vs. low sensitvity pts)

22

advantages of pet?

functional imaging

physiological variables can be determined

23

to study brain structure what could you use

CT or MRI

24

what to use when looking at vascualture? 

MRI

25

what to use when looking at fiber tracts? 

mri

26

what to use when looking at brain perfusion? 

pet

27

what to use when looking at NT integrity? 

PET

28

what to use when looking at metabolism? 

PET

29

what to use when looking at chemical structure? 

MRI

30

elements of ___ atomic numbers show up better on CT

high (ca iron barium lead)

31

on ct, hyodense areas can indicate

edema and infarction

A image thumb
32

hyperdense structures on ct can indicate

Q image thumb

calcifications and hemorrhage and bone trauma 

33

SPATIAL RESOLUTION OF ____ MILLIMETERS IN CT SCAN

SEVERAL

 

34

SPATIAL RESOLUTION IS ___ MILLIMETER IN MRI

ONE

35

with mri, ___ is used isntead of xrays

radiofrequency

36

when the rf pulse is turned off protons ___ with the external magnetic field

realign

37

when RF pulse turns off

the energy from each spinning proton absorbed from the RF ___

decays

38

as energy decays, an ___ is emitted which is picked up by an antennae

rf signal

39

each pixel of an image on an mri is encoded with a nubmerical index that represents the 

relaive strength of the RF signal in the area of the brain

40

each numerical index (which represents an RF signal) corresponds to a 

gray scale level

A image thumb
41

how can a dr adjust an MRI to look at tissue he or she is most interested in?

varying the timing of the rf pulse

42

diag. applications of mri includr

inflammatory disease, neoplastic disease, epilepsy, stroke

43

MRS can derive __ and __

concentrations and ratios of chemicals

44

a ___ is applied with MRS

RF pulse

45

with MRS what represents the concentration of each chemical component of interest

the size of peak

46

on MRS ___ is raised in tumor tissue

choline

A image thumb
47

The difference between T1 and T2 weighted MRI images is due to ____

density of fluids.

48

when a person is performing a task in the MRI scanner that results in increased neural activity, resulting changes in the concentration of _____ is represented by small changes in intensity values on the MR images. 

oxyhemoglobin

49

in control condition of fmri the task is comprised of 

all features of experimental task except the specific cognitive variable of interest

50

what imaging modalities have fairly poor spatial resolution

pet 

FMRI

ct

51

on an FMRI ___ was active during all emotions

amygdala

52

FMRI studies have shown ___ regions important for memory formation have prolonged maturational trajectory

prefrontal cortex 

53

____ has been used in the management of AD, since hypometabolism in various brain regions have been associated with severity of clinical symptoms

PET

54

what is APOE-4 allele related to?

genetic risk for alzheimers

55

APOE-4 allele carriers had inc brain activation during __ tasks

memory

 

after 4 years the degree of brain activity correlated with memory decline

56

which studies use ionizing radiation

ct and pet

57

with studies can provide functional imaging

pet and mri

58

disorders to study with ct

hemorrhages, generalized atrophy

59

disorders to study with mri

tumor

demyination

degenerate disorders

60

disorders to study with pet

psychiatric/addictive/degenerative disorders

epilepsy