Neuroradiology

Question 1

Describe the indications for plain radiographs?

Answer 1

Stroke
Head Trauma
Headache
Cancer
Post-sugerical bleeds or hydrocephalus

Question 2

What are the pros/cons of plain radiographs?

Answer 2

• Quick
• Widely available
• No soft tissue or functional details
• Not as detailed as CT/MRI

Question 3

What are the main types of MRI?

Answer 3

• Functional MRI
• Diffusion weighted MRI (DW-MRI)
• Diffusion Tensor Imaging (DTI)
• T1 vs T2
• FLAIR

Question 4

Whats the difference between T1/T2 MRIs?

Answer 4

T1

• Fluid is black
• Bone is black surrounded by white fat

T2:

• CSF/Water are white
• Brain tissue is darker

Question 5

What is FLAIR MRI?

Answer 5

Fluid Attenuated Inversion Recovery

Basically nulls out fluids like CSF so you can see periventricular lesions better

Looks like T2 but with black CSF

Question 6

What does a functional MRI do?

Answer 6

Detects activity in different parts of the brain in real time.
So you can see what lights up during a certain action

Question 7

What does a DW-MRI do?

Answer 7

Shows up diffusion of water and small molecules

Useful for spotting cytotoxic oedema as part of the necrosis in infarction

Question 8

What does DTI MRI do?

Answer 8

Allows you to build a map of the brains white matter tracts location and orientation
So you can track an individual tract

Question 9

When would you use MRIs?

Answer 9

• Focal Epilepsy
• Demylination e.g. MS
• Developmental/Congenital Malformations
• Red Flag Headache or Raised ICP
• Spinal Cord Diseases
• Cancers

Question 10

Pros and cons of MRI?

Answer 10

• No radiation
• Lots of sequences to detect many different soft tissue and functional details
• Cant tolerate metals of implanted electronics
• Slow
• Expensive
• Not movement tolerant
• Not good for the pregnant, claustrophobic or tattooed

Question 11

How does a CT appear?

Answer 11

• White Bone
• Black CSF & Air

Grainy & Shows subtle grey/white matter differentiation

Metal shows up as white starburst artefacts

Question 12

Pros & Cons of CT?

Answer 12

• Fast
• Tolerates metals & electronic
• Good for Haemorrhage
• Radiation
• Not as available as X-ray

Question 13

What is CT/MRI Perfusion imaging?

Answer 13

Shows up blood flow in ml/100g/min

Used for stroke (decreased perfusion to affected area)
And Tumours (Increased perfusion, level can indicate aggresiveness)

Question 14

Types of cerebral Angiography

Answer 14

Digital Subtraction Angiography with CT images and dye

MRA

Question 15

What is cerebral angiography used for?

Answer 15

• Aneurysms
• Arteriovenous Malformations
• Carotidcavernouis fistulas
• Unstoppable epistaxis

Basically after a bleed or stroke in which theres reason to believe its not a primary bleed

Question 16

What are the main types of nuclear medicine?

Answer 16

• Ioflupane Scan
• PET Scan
• SPECT

Question 17

What does an ioflupane scan do?

Answer 17

Detects activity in the basal ganglia

Reduced activity diagnoses Parkinson’s

Question 18

What does a PET scan show?

Answer 18

Glucose metabolism

• Tumour (metastases and post-resection)
• Inflammation
• Infection

Question 19

What is SPECT and what does it show?

Answer 19

Single Photon Emission CT

Detects perfusion in the brain
Particularly for the early stages of alzheimers where atrophy hasn’t yet become visible

Fuzzy very colourful images

Question 20

Pros and cons of Nuclear Medicine?

Answer 20

• Great physiological info
• Poor anatomical info
• Costly
• Tracers can be costly/slow to obtain

Question 21

When would you use an ultrasound in neuro?

Answer 21

• Through babies fontanelles with colour shift imaging to check CSF/blood flow
• Ocular US
• Carotid US with colour shift imaging for carotid stenosis

Question 22

Pros and cons of Ultrasound?

Answer 22

Pros

• No radiation
• Easy to perform on neonates
• Tolerant to movement
• Cheaper than most other scan

Cons:

• Needs an expert to administer and interpret
• Useless for seeing in head after fontanelles close