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Week 2 (Neuro 2) > Radiology II > Flashcards

Radiology II Flashcards

1
Q

the MRI can be used to image what elements?

which element does it image in medicine?

why?

A
  • can be used to image any element with an odd number of protons
  • in medicine, it is tailored to image / manipulate H+ (one proton)
  • this is b/c there are so many H+ atoms in the body
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2
Q

hydrogen is in what state when bound to a molecule within body tissues?

which body tissues most dense in hydrogem?

A
  • when bound: H+ goes from having 1 elecron + 1 proton to just 1 proton.
  • tissues most abundant with H+: water, fat
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3
Q

what is the significance of a spinning proton?

A

the spinning positive charge creates a tiny electrical current

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4
Q

how does hydrogen behave organically vs in the presence of an external magnetic field?

why is this important?

A
  • no external magnetic field:
    • protons oreinted different directions
    • their individual electric signals cancel out
  • external magentic field (in an MRI):
    • protons align (either parallel or antiparallel)
    • this generates magnetic field
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5
Q

how is an image generated from aligned protons in an MRI?

A
  • a radiofrequency (RF) pulse is sent onto, inducing protons to temporal change their alignments
  • the new spinning magnetic field produce an electrical signal
  • this electrical signal is detected by a antenna (coil) then mapped into an image
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6
Q

what are TE and TR?

A
  • TE (echo time): time between sending RF pulse and measuring the signal
  • TR (reptition time): time between successive RF pulses
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7
Q

what is the difference between T1 and T2 weighted signals?

A
  • T1: fat is white
  • T2: fat AND fluid (CSF, for example) are white
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8
Q

label

T1 vs T2?

A

cerebellar tonsils

T1 (fluid is dark)

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9
Q

label

T1 vs T2?

A

cerebellar tonsils

T2 (eye fluid is white)

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10
Q

tonsillar herniation

  • definition
  • causes
A
  • when tonsils pass inferior to foramen magnum
  • causes:
    • Chiari I malformation, often associated w/ syrnix - congenital, mild
    • intracranial hemorrhage - acquired, life threatning
    • tumor - aqcuired, life threatning
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11
Q

identify

A

tonsilar herniation (inf to foramen magnum)

d/t chiari I malformation

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12
Q

identify

A

tonsillar herniation (inf to foramen magnum)

d/t posterior fossa tumor

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13
Q

label

T1 vs T2

A
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14
Q

label

T1 vs T2

A

T2

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15
Q

label

T1 vs T2

A

middle cerebellar peduncle

T2

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16
Q

how does multiple sclerosis appear on an MRI

A
  • T2 intense plaques (lesions) within white matter, which if often:
    • radiating perpendendicular from lateral ventricles
    • within the corpus collosum
    • in middle cerebellar peduncle
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17
Q

identify

A

multiple sclerosis

plaque (lesion) perpendicular from lateral ventricle

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18
Q

identify

A

multiple sclerosis

plaque (lesions) perpendicular from lateral ventricles

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19
Q

identify

A

multiple sclerosis

plaque (lesion) in corpus collosum

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20
Q

identify

A

multiple sclerosis

plaque (lesion) in the middle cerebellar peduncle

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21
Q

label

A
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22
Q

identify

A

uncal herniation

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23
Q
A

hippocampus

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24
Q

hippocampus atrophy - cause?

A

Athzheimers, commonly

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25
Q

identify

A

atrophied hippocampus

Alzheimers

26
Q

label

T1 vs T2?

A
27
Q

identify

A

epidural hemoatoma

(lens shape)

28
Q

parkinson’s affects what part of the brain?

A

the substantia nigra

29
Q

label

T1 or T2?

A

T2

30
Q

label

T1 vs T2?

A
31
Q

chronic lacunar infarction

  • definition?
  • presentation?
A
  • cause: ischemic stroke to the caudate nucleus
  • presentation: memory loss
32
Q

identify

A

chronic lacunar infarction

33
Q

identify

A

chronic lacunar infarction

34
Q

identify

A

chronic lacunar infarction

35
Q

label

T1 vs T2

A
36
Q

acute cerebral infarction

  • presents how on MRI?
  • and why?
  • how soon after event?
  • with what kind of imaging?
A
  • presents with with T2-hyperintensity
  • d/t restircted water movement b/c of
    • lack of blood flow
    • cytotoxic edema
  • seen as soon as pt appears for care
  • on diffusion waited imaging
37
Q

how does an acute cerebral infarction present on CT as opposed to MRI?

A
  • with ribbon like insular cortex
  • not for several hours after event
38
Q

identify

A

acute cerebral infarction - MRI

T2-hyperintensity on diffusion weighted imaging

39
Q

identify

A

acute cerebral infarction - CT

ribbon like insular cortex

40
Q

identify

A

ependiymitis granularis

  • a normal variant of ventricular ependyma that has
    • less myelin
    • increased ECF
    • some ependymal degeneration
41
Q

label

A
42
Q

what is a “midfline shift”?

what is it caused by?

A
  • aka subfalcine herniation
  • a mass effect on one side of the brain cause a shift of the septum pellucidum away from the midline towards the opposite side
    • ex - subdural hematoma
43
Q

identify

A

subfalcine herniation

in this case, due to subdural hematoma (cresent shape)

first is T1, second is T2

44
Q

label

A
45
Q

label

A
46
Q

hydrocephalus

  • cause
  • variations
  • presentation on MRI
A
  • cause: abnormal increased CSF volume
  • presentation on MRI: ventromegaly
  • variations: non-communicating (no visible obstruction), communicating (visible obstruction)
47
Q

how does normal pressure hydrocephalus present?

A

“wacky, wobby & wet”

  • dementia (wacky)
  • wobby (ataxia)
  • wet (urinary incontinence)
48
Q

label

T1 vs T2?

A
49
Q

label

A
50
Q

pituitary adenomas are divided into what two main types?

how do they differ?

A
  • microadenomas (<1 cm): can produce hormones
  • macroadenomas (>1 cm): can produce hormones & exert significant mass effect?
51
Q

how are macroadenomas typically discovered?

how are they treated?

A
  • by growing large enough to compress the optic chiasm and result in visual symptoms
  • treatment: bromocriptine
52
Q

identify

A

pituitary microadenoma

53
Q

label

A
54
Q

label

A
55
Q

label

A
56
Q

label

A
57
Q

label

A
58
Q

label

A
59
Q

label

A
60
Q

identify

A

cerebral aneurysm

61
Q

identify

A

Week 2 (Neuro 2) (9 decks)

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