CT imaging

Question 1

When to do CT scan

Answer 1

Stroke

TIA

RTA - loss of consciousness

Thunderclap headache - a sign of subarochnal haemorrhage.

I suspected a space-occupying lesion.

EXTRA CRANIAL

• Orbital cellulitis
• Facial trauma
• Evaluation of skull base for bone lesions

Question 2

Criteria for CT within 1 hour when there is a history of trauma

Answer 2

GCS < 13 initial
GCS < 15 2 hours after injury

Suspected open or depressed skull fracture

Any sign of a basal skull fracture

Post-Traumatic seizure

Focal nuerological deficit

More than an epsidoe of vomiting since the head injury.

Question 3

CTB within 8 hours for trauma for head injury

Answer 3

Patient on anticoagulation

LOC
- age >65
- bleeding disorder
- retrograde amnesia

Question 4

What view is a CT ?

Answer 4

CAUDAL

Look as if looking at patients feet

Question 5

Age ?

Answer 5

7-8 Y

Question 6

AGE ?

Answer 6

70-80

SHRINKED

ALOT MORE FLUID ABLE TO MOVE AROUND.

CONSIDERING HEAD TRAUMA THE BRAIN CAN BOUNCE WHICH CAN BE DANERGOUS.

contrecoup injury

Question 7

Age ?

Answer 7

Regular 35

Question 8

Interpreting greyness, what colour will

• bone
• Blood
• air
• CSF

Answer 8

Question 9

What is this location circled where all sutures come together?

Answer 9

Pterion

THE P IS SILENT

+++TERION +++

Question 10

What artery lies under the pterion ?

Answer 10

Middle meningeal artery

supplies the majority of the skin

Can cause …

Question 11

Explain the Monroe-Kellie Doctorine

Answer 11

THE FIRST THINGS TO GO WILL BE VENOUS VOLUME AND CSF.

IF IT CONTINUES AND ARTERIAL BLOOD DOES NOT GO TO THE BRAIN, HYPOXIA WILL OCCUR, AND CELL DESTRUCTION AND DEATH WILL OCCUR.

WHERE WILL THE BRAIN GO ? Concern about raised ICP?

Shift brain structures, cause brain herniation through the foramen magnum, and restrict blood supply to the brain.

LIKELY DEATH.

Question 12

What are the three meninges ?

Answer 12

Question 13

What seperates the cerebella form cerebum

Answer 13

Tentorium

Question 14

Explain a epidural hematima

Answer 14

LEMON SHAPE

OUTSIDE THE DURA

ARTERIAL BLEEDING

DURA IS TORN AWAY FROM THE SKULL.

Question 15

Explain a Subdural hepatoma

Answer 15

Just under the dura

Likely to be an older patient

Rather than arterial blood it’s venous blood so it is not rapidly expanding.

DURA STAYS ATTACHED.

Question 16

Signs of the base of skull fracture?

Answer 16

Bruising over the mastoid

Blood behind the tympanic membrane (ear)

Racoon/ panda eyes (bruising around the eye) because the base runs where the line is in the image.

Question 17

What would you see at the base of skull CT scan ?

Answer 17

Base of skull

A lot of white, because we see a lot of bone

Note the nasal cavities (black because of air)
The globes, optic nerve, pinna of the ear

Pinna is a tiny bit of the ear.

Question 18

What is the suprasellar cistem ?

Answer 18

Suprasellar cistern is star shaped
Sella turcica is below it
Sella turcica (where pituitary gland sits)

Suprasellar cistern—where the circle of willis sits
Common site for aneurysm, with rupture will see blood in this space (subarachnoid)

Question 19

What is the main blood supply to the brain?

Answer 19

Circule of willis

Question 20

What can happen to the circle of Willis?

Answer 20

it can Annurism.

If it does, we can see blood in the suprasellar cistern and this is a subarachnoid heamorridghe.

Question 21

What is myelanated out of white and grey matter

Answer 21

White matter is myelinated grey matter is not.

(ON A CT THE GREY IS THE WHITE MATTER)

Question 22

What is falx cerebri

Answer 22

Dura that separating the two hemispheres

Question 22

How to assess a CT? (ABC’S)

Answer 22

A – Adequacy & Alignment
B – Bones, Blood & Brain
C – CSF spaces
S – Soft tissue +SYMMETRY

Question 23

What is this?

What has happened?

Answer 23

Epidural

Caused by TRAUMA

ARTERIAL BLEED

Mid-line shift

RIGHT SHIFT

Middle meningeal artery - Rappid expansion.

Lead to brain herniation.

Treatment - BEAR HOLES or craniotomy.

Question 24

What is this?

What has happened?

Answer 24

Sub-dural

Elderly

On blood thinners

VENOUS BLOOD.

Treatment - WATCH AND WAIT.

Question 25

What is this?

Answer 25

Subarochnoid haemmorage

This can be due to trauma or aneurysm.

Question 26

What is this ?

Answer 26

Intracerebral haematoma

The irregular shape is consistent with the sulci and gyro. Shift of the mid-line.

This could be due to trauma

Question 27

What is the more common ischemic or haemorrhagic stroke?

Answer 27

Ischemic

That’s why we rarely see things.

That’s why MRI is better than CT.

However, CT must be done first to ensure no bleeding.

THEN GIVE BLOOD THINNERS AND MRI.

Question 28

What is it called when there is not symmetry of the brain?

Answer 28

Mid-Line shift.

Question 29

What are the different types of brain herniation?

Answer 29

Because herniation puts extreme pressure on parts of the brain and thereby cuts off the blood supply to various parts of the brain, it is often fatal. Therefore, extreme measures are taken in hospital settings to prevent the condition by reducing intracranial pressure, or decompressing (draining) a hematoma which is putting local pressure on a part of the brain.

1Uncal (or transtentorial) herniation causes temp lobes pushed into upper cerebellum, against the midbrain leading to compression of Post C Art; IIIn compression and midbrain haemorrhage

4)Always check before you stitch someones scalp that there isn’t brain tissue sticking out

Question 30

Is there a skull fracture within this image?

Answer 30

I would want the bone window.

However, there is air (black space) within; therefore, there must be a way for it to get in! Probable fracture.

Question 31

Coup Contrecoup Injury

Answer 31

A coup injury happens at the point of impact with an object, whereas a contrecoup injury takes place on the opposite side of the skull from the impact.