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Flashcards in Introduction To Neuroradiology Deck (60)
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1
Q

What are the advantages of CT scans?

A

Relatively cheap
Fast
Repeatable

2
Q

What clinical problems would you use CT scans for?

A
Trauma/emergencies
Extracerebral bleeds/clots
Calcified tumours
Basic ventricular imaging (position, blood, enlargement)
Cerebral arterial + venous system
3
Q

What are the advantages of MRI scan?

A

Enhanced resolution

4
Q

What clinical problems are MRI scans used for?

A
Acute stroke (can identify oedema/change in water content)
Degeneration
Neuroinfection
Demmyelination
Tumours
Hydrocephalus
Spinal cord
5
Q

What are the disadvantages of MRI scan?

A

Expensive
Slower
Noisy
Claustrophobic

6
Q

How are coronal sections viewed?

A

Looking at patient face on

7
Q

How are axial sections viewed?

A

Looking at patient through binoculars from their feet

8
Q

What are the different MRI resolutions?

A

1.5T: lowest resolution (not used anymore really)

3T: medium resolution (most common in hospitals)

7T: highest resolution (used for research)

9
Q

What are the layers of the head (from outwards to inwards)?

A
Skin of scalp
Periosteum
Bone of skull
Dura mater (periosteal + meningeal layer)
Subdural space
Arachnoid
Subarachnoid space
Pia mater
Grey matter (cerebral cortex)
10
Q

What is the falx cerebri?

A

Double layered vertical fold of dura mater which is a useful midline marker meaning you can look for deviation

Superior + inferior sagittal dural venous sinuses sit at top and bottom

11
Q

What is the tentorium cerebelli?

A

Double layered horizontal fold of dura mater separating the cerebral hemispheres from the cerebellum

Transverse dural venous sinus sits at attachment to cranium

12
Q

When will you see the dura mater folds on a image?

A

If you are posterior of the cranium

13
Q

What would it suggest if the falx cerebri had deviated from the midline?

A

Pathology occupying space in the cranium pushing it over to one side e.g. tumour or increased ICP

14
Q

What are ventricles?

A

Hollow regions within the brain and brainstem within which CSF is produced

C-shaped paired lateral ventricle drains into unpaired 3rd ventricle then 4th ventricle

15
Q

What colour would the ventricles appear on scans?

A

MRI: white

CT: dark

16
Q

Where are the brain ventricles?

A

Lateral: central parts sit under corpus callosum + by caudate nucleus whereas temporal horns sit low down in temporal lobes having close relation to the hippocampus

3rd ventricle: sit in midline with thalamus lateral

4th ventricle: between cerebellum + brainstem

17
Q

What structures does the venous drainage of the brain pass through?

A

Dural venous sinuses

18
Q

Name the dural venous sinuses.

A
Superior sagittal
Inferior sagittal
Straight
Transverse
Sigmoid
Right cavernous
19
Q

What major vein of the neck do most dural venous sinuses drain into?

A

Internal jugular vein

20
Q

What type of imaging can aid you in looking for dural venous sinus blockage?

A

Magnetic resonance venogram

21
Q

How is the brain interconnected?

A

Cerebral hemispheres interconnect via corpus callosum and connects to brainstem

22
Q

When can images be off-axis?

A

If the patients head isn’t perfectly aligned in the CT/MRI

23
Q

What hole does the brainstem drop through?

A

Foramen magnum

24
Q

What colour would bone appear on scans?

A

MRI: black

CT: white

25
Q

Why do bones often appear unsymmetrical within a CT image?

A

Due to the plane of the cross section taken by the CT which depends on the position of the patients head - DONT CONFUSE WITH PATHOLOGY

26
Q

What is the sensory innervation of the frontal sinus?

A

Same as parts of the dura so referred pain from here will cause a headache

27
Q

What would you do first when looking at an image?

A

Determine which level of section is being reviewed using local anatomical features, paranasal sinuses, fissures + cortical regions

28
Q

What functions are looked superiorly of the frontal and parietal lobes?

A

Primary motor + sensory cortex respectively

29
Q

What does the deep brain nuclei contain?

A

Cell bodies and synapses

30
Q

What are the 2 parts of the globus pallidus?

A

Externus

Internus

31
Q

What is the fornix?

A

Part of limbic system superior of thalamus

32
Q

What is the thalamus?

A

Dense collection of nuclei in the diencephalon of the central brain connecting multiple neuronal pathways to the cerebral hemispheres

33
Q

What is in the internal capsule?

A

Neurons running to and from the cortex

34
Q

What scan shows better resolution of neural tissue?

A

MRI is better than CT so structure identification has to be carried out via region in CT scans

35
Q

How can cortex and deep white matter be differentiated on an MRI?

A

Cerebral cortex is lighter grey whilst deep white matter is darker grey

36
Q

What is the blood supply to the brainstem (superior to inferior)?

A

Post cerebral artery
Basilar artery
Vertebral artery

37
Q

What is the function of the cochlea?

A

Transforms the vibrations of the cochlear liquids and associated structures into a neural signal

38
Q

What are the semi-circular canals of the vestibular system?

A

3 tiny, fluid-filled tubes in your inner ear that help you keep your balance - as you move your head around, liquid moves around moving the tiny hairs that line each canal

39
Q

How can deep brain nuclei be identified on a scan?

A

Position

Contrast difference

40
Q

How does a stroke show up on a MRI scan?

A

Neural tissue infarction show as areas of high signal i.e. lighter coloured watershed affect

41
Q

What are the arteries that supply the cerebral cortexes and hemispheres?

A

Anterior cerebral
Middle cerebral
Posterior cerebral

42
Q

What arteries can be blocked if a stroke occurs in the pons?

A

Pontine arteries

43
Q

Where is the basilar artery?

A

Single midline vessel running off of the centre of the brainstem

44
Q

What cranial nerves pass through the internal acoustic meatus?

A

CN VII

CN VIII

45
Q

What types of blood can haemorrhage in and around the meninges?

A

Arterial AND/OR venous

46
Q

What are the 3 meningeal layers and spaces that surrounds the central nervous system (external to internal)?

A
Epi/extra dural space
1. Dura matter
Subdural space
2. Arachnoid mater
Subarachnoid
3. Pia mater
47
Q

If there is a epi/extra dural space bleed, where is the blood coming from?

A

A meningeal artery e.g. a middle meningeal artery can be caused by lateral cranium fracture damaging the pterion region

48
Q

If there is a subdural space bleed, where is the blood coming from?

A

Bridging veins as subdural space is a potential space containing veins draining the brain into the dura venous sinuses

49
Q

If there is a subarachnoid space bleed, where is the blood coming from?

A

A cerebral artery e.g. due to small aneurysm

50
Q

What is the subarachnoid space full of?

A

CSF

51
Q

What will a cranial epidural haematoma look like?

A

Elliptical biconvex shape

Size can be limited by skull suture joints

Midline shift

May see air in the brain too (black dots) due to connection to outside world

52
Q

Why might a cranial epidural haematoma patient have blood AND cerebrospinal fluid (CSF) coming out of there ear?

A

It may go into the middle ear and burst the ear drum

53
Q

What can long-term warfarin use cause acute paraplegia?

A

Epidural haematoma which will cause compression of brain OR spinal cord and symptoms as a result

54
Q

What will a subdural bleed look like on a CT scan?

A

Between dura and arachnoid mater

Blood will sit OVER sulci and gyri so has a fuzzy border

Midline shift

May look like bone in CT

55
Q

What can help you distinguish between a subdural bleed and bone?

A

Imaging over different points in time

56
Q

How can you determine how recent a brain bleed is?

A

Hyperdense area (lighter colour) = fresh bleed

Isodense (similar colour to surrounding neural tissue) = few weeks after

Hypodense area (darker colour) = chronic/long-term (previous bleed several months ago)

57
Q

Where are subarachnoid bleeds?

A

In subarachoid space so they go into sulci, gyri and fissures

Commonly seen around circle of Willis, lateral fissure, interpeducular fossa + lateral ventricle

58
Q

What type of imaging would you do first?

A

CT as its cheaper + quicker but MRI is more sensitive

59
Q

How can you distinguish a subdural and epidural bleed?

A

Subdural bleeds sit between dura and arachnoid mater so its in closer contact with neural tissue so inner surface of bleed will not look as defined as the clean convex shape of the epidural bleed, it will look fuzzy and follow the contour of the brain

60
Q

How can you detect a bleed in the isodense stage?

A

Sulci and gyri in that area will not be as evident