Radiology: Neuro Flashcards
(55 cards)
1
Q
what is first line imaging for neuro presentations?
A
- CT
well tolerated
with or without contrast
specialist ix including angiography, venography
2
Q
MRI pros and cons in neuro imaging?
A
- better soft tissue resolution, specialist IX and sequences
- longer duration, CI for some and can be poorly tolerated
3
Q
babies what can you use before fontanelle closes?
A
- ultrasound
4
Q
diagram of lobes of brain CT
A
5
Q
what do fissures of the brain do and what do they contain?
A
- they separate structures of the brain
- CSF filled clefts
interhemispheric - seperates cerebral hemispheres - 2 halves of brain
sylvian fissures - separate frontal and temporal lobes - good to look for early strokes
6
Q
name a) herniation?
A
a) Subfalcial (cingulate) herniation
7
Q
name b) and c) herniation
A
b) uncal herniation
c) downward (central, transtentorial) herniation
8
Q
name d) and e) herniation
A
d) external herniation
e) tonsillar herniation
types a), b) and e) are usually caused by focal, ipsilateral SOL i.e. tumour or axial or extra-axial haemorrhage
9
Q
study these structures
A
cover and answer
10
Q
study suprasellar cistern and quadrigeminal cistern on this image
A
- suprasellar cistern is an expansion of SAS above sella turcica, and above pit fossa
- common location for blood to collect in SAH
- can be obliterated in cases of raised intracranial pressure
- quadrigeminal cistern
- CSF filled subarachnoid cisters
- extends from 3rd ventricle to great cerebral vein
- contains vessels and nerves (post cerebral arteries, trochlear nerve etc)
11
Q
study
A
cover and answer
12
Q
what are the 3 parts of the brainstem?
A
- midbrain
- pons
- medulla oblongata
13
Q
on MRI what colour is CSF
A
- dark
- cortex is white and white matter is grey…
14
Q
what is an ischaemic stroke
A
- sudden cessation of adequate amouts of blood reaching parts of brain - deprivation of o2 and glucose
- cascade of events - cell death -> mostly through liquefactive necrosis
- typically presents w rapid onset neuro deficit, determined by area of brain involved
15
Q
describe some types of ischaemic stroke?
A
depends on territory affected/mechanism
embolism
- cardiac embolism - AF, Ventricular aneurysm, endocarditis
- paradoxical embolism - septal defect - go into R heart and into arterial circulation
- atherosclerotic embolism - aortic arch
- fat embolism - long bone fractures
- air embolism - brought about by injecting
thrombosis
- perforator thrombosis: lacunar infarct
- acute plaque rupture w overlying thrombosis
arterial dissection - traumatic or atherosclerotic
16
Q
name 3 vascular territories?
A
- ACA - anterior cerebral artery
- MCA - middle cerebral artery
- PCA - posterior cerebral artery
17
Q
arterial supply
A
- provided by circle of willis
posterior
- 2 vertebral -> basilar artery -> PCA
anterior
- internal carotid -> MCA and ACA
communication
- anterior communicating
- posterior communicating
18
Q
stroke location and symptoms
A
- neuro deficit a patient presents w depends on ANATOMICAL site of insult to brain parenchyma
- e.g. referring to homunculus - hand is bigger as it controls many diff movements etc
19
Q
why do we image strokes?
A
- exclude intracranial haemorrhage
- confirms ischaemia
- exclude other intracranial pathologies - mimicking a stroke - e.g. tumour
- permit rapid tx e.g. thrombolysis or mechanical thrombectomy
20
Q
what imaging do we use for a stroke?
A
- non-contrast CT scan
21
Q
early findings of ischaemic stroke?
A
- earliest CT finding is a hyperdense segment of vessel - intravasc thrombus/embolus and as such is visible immediately
22
Q
first few hours of thrombus on CT?
A
- loss of grey-white matter differentiation
- hypoattenuation of deep nuclei
- cortical hypodensity w assoc parenchymal swelling w resultant gyral effacement
23
Q
with time stroke on CT?
A
- hypoattenuation and swelling becomes more marked - significant mass effect
- more time… gliosis occurs eventually appearing as a region of low density w volume loss i.e. in lateral ventricles
24
Q
reasons for intracranial haemorrhage and how it appears on CT?
A
- trauma or atraumatic
- can be due to underlying lesion
- acute blood appears WHITE on unenhanced scan
- pattern/shape of blood collection is determined by anatomical location
25
intra-axial haemorrhage is defined as?
- haemorrhage occurring within the brain substance
26
extra-axial haemorrhage is defined as? and its 3 divisions?
- outwith brain parenchyma but inside the skull
1. extradural
2. subdural
3. subarachnoid
27
intra-axial haemorrage
- acute haematoma in right occipto-parietal region
- lobar haemorrage
- midline shift to left and blood in posterior horn of left lateral ventricle - can also leak into extra-axial component areas - e.g. subdural
28
haematoma in left basal ganglia occurs usually w what?
- typical appearance of a hypertensive bleed
- note blood in posterior horns of left lateral ventricles
tx: watch swelling, reverse warfarin if on warfarin
29
extradural haemorrage
- collection of blood between inner surface of skull and outer layer of dura
- usually trauma assoc w skull fracture
- bleeding is usually arterial, most commonly from a torn middle mengineal artery - i.e. golf - hit in temple
- biconvex in shape, can cause mass effect w herniation - tx prompt evacuation and stop bleed
- limited by cranial sutures
- less common than subdurals
30
how does extra dural haemorrhage appear on CT?
- biconvex shape
- mass effect - sulcal effacement, midline shift
- worried about coning
31
subdural haemorrhage?
- collection of blood in subdural space - potential space between dura mater and arachnoid mater
- SDH can happen in any age group - mainly due to head trauma
causes - infants - NAI, young adults - RTA, elderly - falls
32
mainstay IX for SDH
- CT
33
what do you see on CT of SDH
- semilunar shape
- crosses sutures
- mass effect
- early dilatation of posterior horn of R Lateral ventricle - when you block off foramen of munroe opp side of brain - ventricle can no longer empty - resulting in one sided hydrocephalus
34
what is this?
- acute on chronic subdural haematoma
35
subarachnoid haemorrhage
- blood within subarachnoid space
- majority assoc w berry aneurysms - so found commonly arround circle of willis
- can be traumatic or other vasc malformations
- hyperdense material is seen filling SAS
36
what imaging for SAH and what will you see?
- unenhanced (non contrast CT) scan
- large vol of high attenuation of acute blood in the:
1. - suprasellar cistern
2. - sylvian fissures
3. - sulci
4. most commonly hyperdense material around circle of willis - hyperdense material is light grey!!!
37
in absence of trauma SAH what other ix will you do on top of unenhanced CT scan
- absence of trauma - cerebral angiography is performed to look for underlying berry aneurysm
38
complications of SAH
- hydrocephalus -> CSF circulates through cisterns and ventricles blood will block arachnoid granulations that reabsorb CSF - build up of CSF in ventricles - you WILL SEE dilatation of temporal horns of lateral horns (bilaterally) - suspect hydrocephalus
- vasospasm - causing delayed cerebral ischaemia - triple H therapy - haemodilution, hypertension, hypervolaemia, ca channel blockers, endovasc intervention
- hyponatraemia
- infarction
39
is primary or metastases more common in intracranial masses?
- mets
40
what are common types of mets to the brain?
- lung
- breast
- melanoma
- renal cell
- colorectal cancer
41
imaging for intracranial masses?
- CT usually first test
- hypo or hyperdense - often rounded
- solitary or multiple
- useful to determine oedema -> mass effect
- contrast may make lesions more conspicuous (depends on integrity of BBB)
42
where are mets found
- brain or cerebellum
- supra or infra tentorial
-> lots of oedema, lots of mass effect, avidly enhance (as not dependent on BBB) - oedema indicates mets
- may have known underlying malignancy - sometimes presenting lesion then primary malignancy is then found
43
primary masses are commonly solitary and found where?
- supra or infra tentorial
- w degree of oedema, mass effect and enhancement depends on grade of tumour(below or above tentorium cerebelli)
44
lesion in intracranial region what happens?
- brain herniation - shift of cerebral tissue from its normal location = mass effect
- common types of herniations:
below cerebri (subfalcine),
uncal or transtentorial (medial temporal lobe) can press on PCA -> causing stroke,
foramen magnum - tonsillar herniation can compress brainstem - compress clivus altering vital life sustaining functions of pons and medulla (resulting in CV and resp problems) - descent of cerebellar tonsils below foramen magnum - tonsillar herniation is often called coning - fatal if not corrected
45
complication of intracranial mass?
- hydrocephalus
- flow of CSF becomes impaired either due to anatomical obstruction of normal reservoirs/channels or because it can no longer be reaborbed - blood in subarachnoid space
- upstream CSF spaces become dilated and CSF breaks out across barriers
46
where is spinal cord found and what is it's extension?
- spinal cord is found within spinal canal of vertebral column
- and is contained by thecal sac
- extends from corticomedullary junction at foramen magnum of skull down to tip of conus medullaris
- divides into cervical, thoracic and lumbar parts
47
at what level does spinal cord terminate?
- at the conus medullaris - L1 approx in adults
48
what lies anterior to the spinal cord?
- vertebral bodies
49
what lies posterior to the spinal cord?
- spinous processes
50
what is better to visualise spinal cord? CT or MRI?
- MRI
- CSF is bright on MRI
51
what is spinal cord compression and what is immediate tx?
- surgical emergency
- requires prompt surgical decompression to prevent permanent neuro damage
- if spinal roots below conus medullaris are involved -> termed cauda equina syndrome
52
causes of spinal cord compression
- intervertebral disc
disc protrusion, disc extrusion, discitis, osteomyelitis
- vertebral
trauma (vertebral crush fracture -> goes back and impinges on spinal cord), tumour
- epidural space
epidural abscess/epidural haematoma
- dura
spinal meningioma
- intradural space
nerve sheath tumour
53
initial ix imaging for spinal cord compression?
MRI spine - as it means you can visualise the spinal cord and conus
54
typical symptoms to look out for in spinal cord compression?
- loss of power in lower limbs
- loss of sensation
- saddle anaesthesia
- urinary retention
55
red flags of back pain?
- hx of malignancy
- major trauma
- thoracic/radicular pain
- constant, progressive, non-mechanical pain
- systemically unwell
- widespread neuro signs and symptoms
