Neuroradiology

Question 1

Advantages of ultrasound (4)

Answer 1

No radiation

Less expensive equipment

Can be performed in the
neonatal unit

Movement tolerant

Question 2

Disadvantages of ultrasound (2) one is neuro related

Answer 2

Neuro related: Requires a wide
enough open fontanelle
i.e. up to about 1 year of
age

Image quality and
interpretation based on
operator skill

Question 3

Advantages of plain radiographs ie x-rays (3)

Answer 3

Almost universal
availability

Fast

Sequential images in
subtraction angiography

Question 4

Advantages of CT imaging (3)

Answer 4

Rapid

Metal and pacemaker tolerance

Good for demonstrating acute haemorrhage

Question 5

Disadvantage of x-ray imaging (1)

Answer 5

lacks soft tissue detail

Question 6

Disadvantages of CT scans (2)

Answer 6

Radiation - 2 msv

more expensive, heavy/large equipment

Question 7

Advantages of Radionuclide radiology

Answer 7

Gives you physiological information:
• Glucose metabolism
• Perfusion
• Dopamine reuptake
receptors

Question 8

Disadvantages of radionuclide radiology

Answer 8

Unclear anatomical
information

Medium cost of equipment

Radiotracers can be
expensive

Question 9

Advantages of MRI (3)

Answer 9

No radiation

Soft tissue differentiation

Physiological information:
• blood flow
• diffusion restriction
• metabolite
concentrations

Question 10

Disadvantages of MRI (6)

Answer 10

Poor tolerance of metalwork

Magnetic sensitive
electronics may fail or are
contraindicated
• Pacemakers!
• Cochlear implants
absolutely contraindicated

Least movement tolerance

Slow, must limit sequences

Most expensive equipment

Danger of metallic objects
becoming projectiles

Question 11

What are some important neurological emergencies needing urgent imaging? (4)

Answer 11

trauma
acute stroke
cauda equina compression
subarachnoid haemorrhage

Question 12

How do you identify an ultrasound scan? (2)

Answer 12

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

noisy image

Question 13

How do you identify radionuclide radiology/ nuclear medicine/PET?

Answer 13

images often have bright and varied colours

image is fuzzy

Question 14

How do you identify an MRI scan

Answer 14

White CSF is the best clue, but only true for T2-
weighted MRI

Better grey-white matter differentiation than CT

Image quality - has a JPEG-like quality, usually not grainy

Question 15

How do you identify a CT scan

Answer 15

White circle of skull

Black CSF in sulci and ventricles. Air is black.

Grey brain with subtle grey-white matter difference

Metal = white

Question 16

Why do we do PET scans

Answer 16

PET is usually used to map out glucose usage

Increased metabolism is seen in:-
• Tumour
• Inflammation
• Infection

Useful after brain tumour resection for differentiating
granulation tissue (low energy usage) from leftover
tumour (high energy usage).

Question 17

Why do we do CT perfusion scans? (although not common)

Answer 17

Perfusion is defined as the volume of blood passing
through a defined volume of tissue per unit time

Disorders of abnormal perfusion
• Stroke – decreased perfusion
• Tumour – increased perfusion indicates angiogenesis
and a more aggressive tumour

Question 18

Uses of angiography in the diagnosis of neurological pathology?

Answer 18

Large vascular (arterial and venous) abnormalities

Diagnosis and treatment of:-

1. Aneurysm
2. Arteriovenous malformation
3. Carotid-cavernous fistula - abnormal connection between an artery in your neck and the network of veins at the back of your eye
4. Unstoppable epistaxis (haemorrhage - bleeding nose)

Question 19

Contraindications to perform MRI scan

Answer 19

Implanted electronics (check with manufacturer):
• Cardiac pacemakers, implantable defibrillators,
cochlear implants
• Relative contraindication for programmable shunts,
insulin pumps

Moveable metallic implants (check make and model):
• Aneurysm clips, heart valves, recent intra-abdominal
clips

Relative contraindications
• Claustrophobia, pregnancy, tattoos

Question 20

Why might a neurologist request an MRI scan? (4)

Answer 20

– Demyelination: for example, to help diagnose multiple
sclerosis

– Epilepsy: NICE and SIGN guidelines (and if surgery is
contemplated)

– Paediatric neurology: disorders of development, head
circumference, congenital malformations

– Headache: benign intracranial hypertension

Question 21

Reasons why you wouldn’t perform a CT scan

Answer 21

Minor head trauma

Seizure - choose MRI usually

Question 22

Indications to perform a CT scan

Answer 22

Head trauma

Acute stroke

Headache - red flags for suspected tumour or subarachnoid haemorrhage

Cancer - looking for metastatic brain tumours in patients with symptoms

Post surgical - haemorrhage, hydrocephalus

Question 23

Indications to perform MRI

Answer 23

Mostly under specialist physicians:

Epilepsy

Demyelination (MS?)

Spine (inter-vertebral disk compression with resulting neural compression)

Cancer (Number, location and aggression of brain tumours)

Paediatric neurology (Disorders of development? head circumference, congenital malformations)

Stroke

Headache (benign intracranial hypertension?)