Neuroradiology Flashcards

1
Q

what appears dark, bright, black and grey on the T1W MRI?

A

Dark: Fluid - CSF, Edema, most lesions
Bright: Fat - Blood (metGb), gadolinium (Gd,contrast)
Black: no water or fat protons: air, calcium, dense bone
Grey: gray and white matter

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2
Q

what is the T1 MRI useful for?

A
  1. borders b/w the brain and CSF (e.g. sulci, ventricles, cysts)
  2. not very sensitive to lesions
  3. pre-contrast images
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3
Q

how to recognise a MRI?

A
  • repeated multiple orientations
  • looks like CT
    > ventricles: dark
    > scalp: bright
  • orbits(tracts attaching the eye socket to optic nerves): bright, globes(eye socket): black
  • vessels normally not seen
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4
Q

what are the uses of T1W images with Gd contrast?

A

useful for visualisation of:

  1. normal vessels
  2. vassalar changes
  3. disruption of BBB
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5
Q

how to recognise T1W with Gd?

A

like non-contrast T1 but with bright arteries and veins

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6
Q

what appears dark, bright, black and grey on the T2W MRI?

A

bright: fluid - CSF, blood, edema and most lesions
dark: white and grey matter
black: air, calcium, dense bone, flow

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7
Q

what are the uses of T2W MRI?

A
  • brain anatomy (shows CSF spaces)
  • most brain lesions
  • cannot distinguish lesions from CSF (ventricles, sulci)
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8
Q

how to recognise the T2W MRI?

A
  • > CSF(ventricles, cisterns, sulci) - bright
  • > Scalp - bright
  • > eyes - bright
  • > vessels - black (flow void)
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9
Q

what is a FLAIR scan?

A
  • fluid attenuated inversion recovery
  • same as T2 except free CSF
  • most pathology: bright
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10
Q

what is the T2W useful for?

A
  • same as T2
  • most lesions
  • especially good for lesions near ventricles or sulci (MS)
  • improves gray/white distinction
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11
Q

how to recognise a FLAIR?

A
  • superficially resembles T1
  • bright pathology
  • often bright areas around ventricles
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12
Q

what is DWI?

A
  • diffusion weighted imaging
  • sensitive to passive diffusion of water
  • areas of restricted diffusion - BRIGHT
  • restricted diffusion occurs in cytotoxic edema: ischemia (within mins), seizures, abscess, tumours, vascogenic edema
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13
Q

what is an ADC map?

A
  • apparent diffusion coefficient map

- areas of restricted diffusion are dark

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14
Q

what is the difference between DWI and ADC?

A

areas of restricted diffusion
DWI - BRIGHT
ADC - DARK

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