Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MIMS > Imaging > Flashcards

Imaging Flashcards

1
Q

what does MRI stand for?

A

magnetic resonance imaging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

what does CT stand for?

A

computed tomography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what does PET stand for?

A

positron emission tomography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why is image contrast needed in clinical imaging?

A

to distinguish different tissues from each other, and pathological tissues from normal tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how can contrast medium be given?

A

via GI tract (orally/rectally), via vasculature (IV/IA), into joint (intra-articular), into spine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how do radiographs work?

A

exploit attenuation of X-rays in tissue to generate contrast between tissues of different densities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is often used as a contrast medium in GI tract radiographs, what does this help to identify?

A

barium sulphate, mucosal abnormalities in GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how does an ultrasound work?

A

transmits high frequency sound waves into tissue, assesses returning signal to generate images of tissue non-invasively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how is the transducer used in ultrasound?

A

handheld, placed over area of interest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is gel used for in ultrasound?

A

used on skin to enhance transmission of signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

why is ultrasound used in children and pregnant individuals?

A

safe as doesn’t involve ionising radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is ultrasound imaging particularly useful for?

A

assessing solid organs such as liver and kidneys, assessing female reproductive tract, fetal assessment, detecting fluid accumulation, guiding biopsies, assisting interventional procedures such as drainages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how does CT work?

A

cross-sectional imaging tool that generates 3D images using a rapidly moving gantry containing an X-ray source and detectors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what contrast is often used in CT?

A

iodine based contrast agents given intravenously (allows intra-abdominal organs to be assessed)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is CT used for and why?

A

widely used to detect range of pathological conditions. rapid, relatively inexpensive, can be used to generate images of whole body and generate images at multiple points to evaluate dynamic changes following administration of contrast medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

small downside of CT?

A

involves low dose of ionising radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what principles is MRI based on?

A

principles of nuclear magnetic resonance (NMR) and localisation of NMR signal within body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what nucleus is routinely probed in clinical practice for MRI and why?

A

hydrogen nucleus (proton)- water is most abundant hydrogen containing molecule in body for detection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

why is MRI a very versatile tool?

A

wide range of tissue contrast mechanisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is DCE MRI?

A

dynamic contrast-enhanced MRI

20
Q

how doe DCE MRI generate imaging of tumours?

A

by quantitatively assessing perfusion and the leakiness of the vasculature that is characteristic of the neovasculature that forms within malignant tumours

21
Q

what is DWI?

A

diffusion weighted imaging

22
Q

what does DWI do?

A

detects the small changes in the molecular movement of water that occur in the presence of tumours

23
Q

how does PET imaging work?

A

utilises positron emission from unstable nuclei- subsequently undergoes annihilation in tissue when it collides with an electron- resultant energy production can be used to localise positron with high sensitivity

24
Q

what molecule is typically used in PET?

A

a derivative of glucose (2-fluoro-2deoxyglucose) labelled with the positron-producing nucleus fluorine-18 (18F-FDG)

25
Q

how does 18F-FDG enter cells?

A

uptake by glucose transporters, phosphorylation by hexokinase means it accumulates within cell

26
Q

why is 18F-FDG an excellent method to identify tumours?

A

more rapidly transported and metabolised in tumours than normal tissue

27
Q

what is PET frequently combine with?

A

CT

28
Q

roles of imaging in oncology?

A

detecting and staging cancers (CT + MRI), guiding biopsies to regions of interest (ultrasound), detecting changes in tumour size during and after treatment (CT), repeat imaging over time to assess patient progression, early cancer detection

29
Q

what change in glucose metabolism in tumours is a key hallmark of cancer?

A

often undergoes anaerobic metabolism to lactate even in presence of oxygen despite this being energetically unfavourable

30
Q

what oncometabolites may be elevated in cancer driving tumour formation?

A

2-hydroxyglutarate in isocitrate dehydrogenase (IDH) mutated tumours; fumarate in fumarate hydrase (FH) mutated tumours; succinate in succinate dehydrogenase (SDH) mutated tumours

31
Q

what is a highly sensitive method to detect altered metabolism as part of tumour staging?

A

18F-FDG with PET-CT

32
Q

how can MR spectroscopy be used to assess metabolic changes?

A

by detecting specific metabolites and how these change with treatment

33
Q

what does hyperpolarised carbon-13 MRI do to the signal-to-noise of the detected nuclei?

A

increases it 4-5 times

34
Q

what molecule is typically used in hyperpolarised carbon-13 MRI?

A

13C-labelled pyruvate injected intravenously

35
Q

what happens to the 13C-labelled pyruvate injected in hyperpolarised carbon-13 MRI?

A

converted to 13C-lactate in tumour tissue, converted into 13C-bicarbonate in brain and heart, converted into 13C-alanine in muscle and liver, enter TCA cycle

36
Q

what enzyme converts 13C-pyruvate to 13C-lactate?

A

LDH

37
Q

what enzyme converts 13C-pyruvate to 13C-bicarbonate?

A

pyruvate dehydrogenase

38
Q

what enzyme converts 13C-pyruvate to 13C-alanine?

A

alanine transaminase

39
Q

what enzyme enters 13C-pyruvate into the TCA cycle?

A

pyruvate carboxylase

40
Q

what is DMI?

A

deuterium metabolic imaging

41
Q

how does DMI work?

A

patients drink glucose labelled with deuterium (nucleus detectable using MRI), this is subsequently taken up by tumours and converted into 2H-lactate or 2H-glutamate/2H-glutamine, as measures of non-oxidative and oxidative metabolism respectively

42
Q

which imaging methods don’t use ionising radiatio?

A

MRI, ultrasound

43
Q

what is gadolinium used as a contrast in MRI to measure?

A

tumour vascularity, whether it’s disordered, heterogenous, leaky

44
Q

why does GD3+ have a large magnetic moment?

A

7 unpaired electrons in outer cell

45
Q

how is toxicity of GD3+ reduced, where does GD3+ accumulate?

A

chelation, accumulates in skin and brain

46
Q

how is increased neuronal activity detected in functional MRI?

A

increase in neuronal activity causes local vasodilatation and blood flow. detected with blood oxygen level dependent (BOLD) imaging

47
Q

what is SPECT?

A

single photon emission computed tomography

MIMS (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions