Neuroradiology

Question 1

when would you perform a CT scan

Answer 1

head trauma - NICE
acute stroke - NICE
headache - red flags for suspected SAH
cancer - mets
post surgical - hydrocephalus, haemorrhage

flexible, common sense, happy to discuss

Question 2

when might you not perform a CT

Answer 2

minor head trauma exclusion criteria

seizure - NICE usually MRI
- primary generalised (no imaging)

Question 3

what are the indications to perform an MRI scan

Answer 3

demyelination 
CNS tumours 
spine - disc prolapse 
TIA
epilepsy
paediatric neurology
headache

Question 4

why might neurologists perform an MRI

Answer 4

demyelination - MS diagnosis

epilepsy - NICE, SIGN, if surgery contemplated

paediatric neurology - development disorders, head circumference, congenital malformations

headache - benign intracranial hypertension

Question 5

why might surgeons perform an MRI

Answer 5

spine - intervertebral disc degeneration, neural compression

cancer - clarifying number, location, aggressiveness

Question 6

what are the contraindications to perform an MRI

Answer 6

implanted electronics
- cardica pacemakers, defibs, cochlear implants, shunts, insulin pump

moveable metallic implants - aneurysm clips, heart valves, intra-abdominal clips

claustrophobia

pregnancy

tattoos

Question 7

what can angiography be used to diagnose and treat

Answer 7

large vascular abnormalities 
aneurysm
arteriovenous malformation
carotidocavernous fistula
unstoppable epistaxis

Question 8

what is perfusion

Answer 8

the volume of blood passing through a defined volume of its per unit time

Question 9

what are some disorders of abnormal perfusion

Answer 9

stroke - decreased

tumour - increased (indicates angiogenesis and a more aggressive tumour)

Question 10

what type of imaging can be used to determine if there is abnormal perfusion

Answer 10

CT/MRI perfusion

Question 11

what is a PET scan used for

Answer 11

to map out glucose usage

i.e. can show increased metabolism

Question 12

when is a PET scan used

Answer 12

tumour
inflammation
infection

after brain tumour resection for differentiating graduation tissue from leftover tumour (high energy usage)

Question 13

how could you recognise a plain radiograph

Answer 13

Multiple superimposed bones, bones are white

Immediately recognisable body parts

Soft tissue is grey

Air is black

Question 14

how could you recognise a CT

Answer 14

white circle of skull

black CSF in sulk and ventricles

black air

grey brain with subtle grew/white matter different

metal produces white starburst artefacts

Question 15

how is the image formed and what is the image quality of a CT

Answer 15

reconstructed by back projection from annotating fan bean of X-rays

slightly grainy

Question 16

how could you recognise an MRI

Answer 16

black circle of skull

white circle of cutaneous fat

better grey/whote matter differentiation

best clue - white CSF in T2

Question 17

how is the image formed and what is the image quality of an MRI

Answer 17

reconstruct from fourier transforms of radio signals

JPEG-like quality
usually not grainy

Question 18

how could you recognise a PET scan

Answer 18

images often have bright and varied colours

image is fuzzy

Question 19

how could you identify an ultrasound

Answer 19

wedge shaped image with the edges of the image diverging away from top to bottom

objects which block the ultrasound beam (air, bone, stones) cast shadows downwards

Question 20

what is the image quality of US

Answer 20

very noisy image - lie an old-tuned TV))

Question 21

what are 4 important neurological emergencies that require neuroradiology

Answer 21

trauma
acute stroke
cauda equina syndrome
SAH

Question 22

what are the advantages and disadvantages of plain radiographs

Answer 22

+
almost universal availability
fast
sequential images in subtraction angiography

-
lacks soft tissue detail

Question 23

what are the advantages and disadvantages of US

Answer 23

\+
no radiation
less expensive
safe for neonates
movement tolerant 

• requires wide enough open fontanelle (up to ~1yr olds)
  image quality and interpretation based on operator skill

Question 24

what are the advantages and disadvantages of CT

Answer 24

+
rapid
metal and pacemaker tolerant
good for acute haemorrhage

-
radiation
more expensive cumbersome equipment

Question 25

what are the advantages and disadvantages of radionuclide radiology

Answer 25

+
glucose metabolism
perfusion
dopamine reuptake receptors

-
unclear anatomical info
medium cost equipment
radiotracers expensive

Question 26

what are the advantages and disadvantages of MRI

Answer 26

+
no radiation
soft tissue differentiation
blood outflow, difusion, [metabolites]

- 
poor metal tolerance
no pacemakers, cochlear implants
least movement tolerance
slow
most expensive
metallic objects can become projectiles