1) Brain Trauma

Question 1

Imaging considerations

• Radiography (why reduced? Visualisation of____ indicative of____, What is normally seen in radiograph?)
• US (useful for__, doppler ___)
• CT ( benefits, useful for___)
• MRI (excellent for which diseases/anatomy?)
• Interventional (cerebral angio useful for___, used to diagnose___, techniques include___)

Answer 1

Radiography

• Largely reduced for evaluation of cranial trauma (due to CT)
• Visualisation of enlarged or deformed pituitary fossa can be indicative of pituitary tumour
• Calcified pineal gland situated in midline can be seen in approx. 60% of skull radiographs

US

• Useful for brain evaluation of neonates before fontanelle closure
• Doppler US is a non-invasive modality useful for evaluating carotid blood flow

CT

• rapid, non-invasive, safe, accurate modality
• Useful for cerebral bleeding evaluation following trauma

MRI

• Modality choice for CNS imaging
• excellent evaluation of all types of spinal diseases, brain tumours, and conditions such as strokes and infections
• excellent for brainstem and posterior cranial fossa evaluation

Interventional

• cerebral angio is used for demonstration of vessels in neck and brain
• used to diagnose stenosis, aneurysms, arterial venous malformations (AVM)
• interventional techniques include angioplasty, stent or shunt placement, thrombolysis or embolisation

Question 2

Ischaemia (define, how many minutes before irreversible damage)

Answer 2

Absolute or relative shortage of blood supply to an organ. Lack of oxygen for more than 4/5 minutes causes irreversible damage

Question 3

Hydrocephalus (what is it, causes, slow developing signs, foetus signs, adult symptoms, treatment)

Answer 3

• Excessive accumulation of CSF within the ventricles causes ventricular enlargement due to decreased absorption of CSF (most common) or overproduction of CSF
• In slowly developing hydrocephalus: skull thinning, cortical atrophy, attenuation of basal nuclei and thalamus
• Foetus or infancy: enlargement of head and separation of sutures
• Adult acute hydrocephalus: intracranial pressure symptoms including headache, vomiting, papilledema
• treatment is usually implantation of shunt to drain excess CSF into the peritoneal cavity

Question 4

Brain trauma (2 types)

Answer 4

Concussion

• Temporary disruption of synapses, no oedema
• Not visible on CT

Contusion

• Bruising on brain often visible on CT
• results from forceful impact of brain inside skull, two types…
• -> coup: contusion at impact site
• -> contre coup: Contusion completely opposite impact site

Question 5

Brain trauma bleeding (where does it occur, causes, acute & chronic appearance, suture lines and dural reflections)

Answer 5

Epidural

• Occurs between skull and dura mata
• Rupture of (usually) middle meningeal artery caused by skull fracture (arterial bleed)
• CT (acute): lenticular biconvex hyperdense area immediately beneath skull vault
• CT (chronic): crescentic
• does not cross suture lines, does cross dural reflections

Subdural

• Occurs between dura and arachnoid mata (venous bleed)
• Caused by tearing of bridging veins. Symptoms slowly develop, haematoma becomes encapsulated
• CT (acute): characteristic “comma” shape on axial images, crescentic and concave
• CT (chronic): biconvex and approach CSF density
• Does cross suture lines, does not cross dural reflections

Subarachnoid haemorrhage

• Intracranial bleed into the subarachnoid space has high density appearance on non-con CT
• Trauma, aneurysm rupture, leaking AVM,

Question 6

Haematoma vs haemorrhage

Answer 6

Haematoma: Localised mass of extravasated blood that is confined
Haemorrhage: escape of blood through ruptured or unruptured vessel wall