Workbook - Neuroradiology

Question 1

What direction are conventional CTs viewed from?

Answer 1

Below, with the patient looking up.

(^ = anterior, > = left,

Question 2

What sort of images are CTs?

Answer 2

Axial images.

-not truly horizontal

Question 3

What are the main differences between CT and MRI?

Answer 3

CT: - x-rays (radiation)

• cost; medium
• contraindications; pregnancy
• best detail; bone

MRI: -magnetic fields (no radiation)

• cost; high
• contraindications; metal implants
• best detail; soft tissue

Question 4

When are CTs commonly used for in neuroimaging?

Answer 4

Stroke, tumour, head injury.

Question 5

When are MRIs most useful?

Answer 5

Haemorrhage, ischaemia.

-pituitary gland & brainstem

Question 6

What appears bright (AKA hyperdense) on CT?

Answer 6

Blood

Bone

Question 7

What appears bright (AKA hyperdense) on T1 weighted MRI?

Answer 7

Fat
Protein
Melanin
Contrast

Question 8

What appears bright (AKA hyperdense) on T2 weighted MRI?

Answer 8

Fluid

Question 9

What appears dark (AKA hypodense) on CT?

Answer 9

Oedema
CSF
Chronic blood

Question 10

What appears dark (AKA hypodense) on T1 weighted MRI?

Answer 10

Fluid

Question 11

What appears dark (AKA hypodense) on T2 weighted MRI?

Answer 11

Fat

Question 12

In what type of scan is bone very white?

Answer 12

CT scan.

Question 13

Which regions of the brain does the anterior cerebral artery supply?

Answer 13

• Medial and upper frontal lobe

- Superior parietal lobe

Question 14

Which regions of the brain does the middle cerebral artery supply?

Answer 14

• Most of lateral surface (except upper parietal and frontal lobes, and inferior temporal)
• Broca’s area
• Wernicke’s area

Question 15

Where is Broca’s area located?

Answer 15

Lateral inferior frontal lobe.

Question 16

Where is Wernicke’s area located?

Answer 16

Lateral temporal lobe.

Question 17

Which regions of the brain does the posterior cerebral artery supply?

Answer 17

• Inferior/medial temporal lobe

- Occipital lobe (midbrain & thalamus)

Question 18

What is TACI?

Answer 18

Total Anterior Circulation Infarct.
-cerebral infarction that affects anterior circulation affecting one side of the brain
» motor and sensory defects, dysphasia, etc.

Question 19

What is PACI?

Answer 19

Partial Anterior Circulation Infarct.
-cerebral infarction that affects part of anterior circulation affecting one side of the brain
» partial motor and sensory defects, dysphasia, etc

Question 20

What is POCI?

Answer 20

POsterior Circulation Infarct.
-cerebral infarction that affects posterior circulation affecting one side of the brain
» nerve palsy, bilateral motor and sensory defects, cerebellar dysfunction

Question 21

What is a lacunar stroke (LACI)?

Answer 21

Stroke due to occlusion of one of the penetrating arteries to the brain’s deep structures.

Question 22

What are the CT findings for a right-sided infarct? (2)

Answer 22

• Loss of grey-white differentiation

- Oedema on right

Question 23

How will patients with right-sided infarct due to the middle cerebral artery present?

Answer 23

• Expressive aphasia

- Contralateral weakness

Question 24

How does acute infarct appear on a CT?

Answer 24

Hyperdense / bright.

Question 25

How does subacute infarct appear on a CT?

Answer 25

Isodense / grey.

Question 26

How does chronic infarct appear on a CT?

Answer 26

Hypodense / dark.

Question 27

What type of scan should be used for imaging the posterior fossa?

Answer 27

MRI.

Question 28

What are the anatomical components of the basal ganglia? (3)

Answer 28

- Corpus striatum (caudate & lentiform nuclei) - Substantia nigra - Subthalmic nucleus

Question 29

What is a subarachnoid haemorrhage?

Answer 29

Bleeding into the subarachnoid space. | -spontaneous / due to head injury

Question 30

What type of vessel is involved in a subarachnoid haemorrhage?

Answer 30

Circle of Willis artery.

Question 31

What is the distinctive symptom for a subarachnoid haemorrhage?

Answer 31

'Thunderclap' headache. | -nausea, photophobia, double vision

Question 32

What is a subdural haemorrhage?

Answer 32

Bleeding between dura mater and arachnoid mater.

Question 33

What type of vessel often causes a subdural haemorrhage?

Answer 33

Tearing in a small bridging vein. | e.g. due to head injury

Question 34

What is an extradural haemorrhage?

Answer 34

Bleeding between dura mater and the skull.

Question 35

What is a common cause of an extradural haemorrhage?

Answer 35

Trauma/skull fracture >> torn meningeal artery (normally middle).

Question 36

What are the characteristics of an extradural haemorrhage scan?

Answer 36

Large lentiform bleed. | -lens shaped

Question 37

How is an extradural haemorrhage treated?

Answer 37

Burr hole >> reduce ICP. | -medical emergency

Question 38

What is a contre-coup injury?

Answer 38

Impact to head >> injury on opposite side of brain.

Question 39

What vessel is responsible for a right occipital infarct?

Answer 39

Posterior cerebral artery.

Question 40

Why might a patient with a right occipital infarct present with a left homonymous hemianopia?

Answer 40

Brain contains visual pathways to opposite side. | -damage >> opposite visual field loss

Question 41

What are the distinguishing features of a haemorrhagic stroke? (3)

Answer 41

- Bright blood - Mass effect - Blood vessel in brain burst

Question 42

What are the distinguishing features of an ischaemic stroke? (4)

Answer 42

- Bright thrombus in vessel (blocks blood flow) - Loss of grey/white differentiation - Oedema (dark/hypodense) - Mass effect

Question 43

What causes a haemorrhagic stroke?

Answer 43

Aneurysm burst or weakened vessel (leak) in the brain.

Question 44

What causes an ischaemic stroke?

Answer 44

Blood clot blocks the flow of blood and oxygen to the brain. | -e.g. due to atherosclerosis

Question 45

What is the most common type of stroke?

Answer 45

Ischaemic stroke.