Neuroradiology

Question 1

Indications to perform a CT scan?

Answer 1

• Head trauma (NICE guidelines)
• Acute stroke (NICE guidelines)
• Headache
• Suspected cancer
• Post surgical (hydrocephalus, haemorrhage)

Question 2

indications to perform an MRI scan?

Answer 2

• Demyelination (Suspected MS)
• Epilepsy (find cause)
• Paediatric neurology: developmental disorders
• Headache
• Suspected spinal issues (Intervertebral disc degeneration)
• Oncology: number / location / aggressiveness of brain tumours

Question 3

Contraindications to performing MRI scans?

Answer 3

• Implanted electronics (pacemakers / defibrillators / cochlear implants)
• Moveable metallic implants (aneurysm clips / heart valves / intra-abdominal clips)
• Claustrophobia / pregnancy / tattoos

Question 4

What is angiography used to diagnose with regards to neurological pathology?

Answer 4

Large vascular abnormalities

• Aneurysms
• Arteriovenous malformation
• Carotidocavernous fistula
• Unstoppable epistaxis (nosebleeds)

Question 5

What is a carotid-cavernous fistula?

Answer 5

• Abnormal communication between arterial and venous systems at the cavernous sinus in the skull
• Engorgement of venous vasculature results from arterial blood entering at too high a pressure

Question 6

What is CT perfusion scanning used to measure? What conditions can be investigated via this method?

Answer 6

• Measures perfusion of tissues (volume of blood passing through tissue per unit time / mL blood/100g tissue/min)
• Stroke: decreased perfusion
• Tumour: increased perfusion indicates angiogenesis and a more aggressive tumour

Question 7

What does a PET scan analyze?

Answer 7

Used to map out glucose usage

Detects tissues with abnormal metabolisms

Question 8

What types of pathology induce increased metabolism that may be seen on PET scan?

Answer 8

• Tumours
• Inflammation
• Infection

Question 9

Why is a PET scan useful post-tumour resection?

Answer 9

Can differentiate between:

• Granulation tissue (low metabolism)
• Left over tumour (high metabolism)

Question 10

What colour is CSF on CT?

Answer 10

Black

Question 11

How do more dense tissues appear on CT?

Answer 11

• The more dense, the lighter

bone = white, air = black

Question 12

How can you tell between an MRI and CT scan?

Answer 12

• CSF on MRI usually white (not always..?)
• Better grey-white matter differentiation on MRI
• MRI less grainy

Question 13

Advantages of an ultrasound scan?

Answer 13

• No radiation
• Cheap
• Movable

Question 14

Disadvantages of ultrasound?

Answer 14

• Requires wide enough fontanelle (only really applicable to those <1 year of age)
• Image quality and interpretation dependent on operator skill

Question 15

Advantages of X-rays?

Answer 15

• Almost universally available
• Fast
• Sequential images in subtraction angiography

Question 16

Disadvantages of X-Rays?

Answer 16

Can’t really see soft tissue detail`

Question 17

Advantages of CT scanning?

Answer 17

• Rapid
• Metal and pacemaker tolerance
• Good at visualizing acute haemorrhage

Question 18

Disadvantages of CT scanning?

Answer 18

• Radiation involved
• Expensive equipment
• Not really movable

Question 19

Advantages of MRI scanning?

Answer 19

• no radiation
• Soft tissues differentiation
• Can depict blood flow / diffusion restriction / metabolite concentrations

Question 20

Disadvantages of MRI scanning?

Answer 20

• Poor tolerance to metalwork
• Magnetic sensitive implants contraindicated
• Slower
• Expensive equipment