Neuro CT 1: Head Flashcards
What is a CT brain scan?
Series of axial slices through the skull and brain from below the foramen magnum to vertex.
What are common CT brain indications? (7)
- Stroke (ishchaemic/haemorrhagic)
- Primary secondary malignancy
- Trauma
- Confusion / unexplained coma
- Aneurysm/AVM
- Hydrocephalus
- Epilepsy/ Seizure
What are the clinical indications for non-contrast CT? (5)
Trauma Haemorrhage Stroke Hydrocephalus Calcification
What are clinical indications for IV contrast?
Aneurysm/AVM
Abscess/Inflammation
Neoplasm/Metastases
What’s involved in ‘sequential/axial’ mode?
Data’s acquired during full rotation and table is moved out for next acquisition.
What’s involved in ‘continuous’ mode?
Continuous gantry rotation & data acquisition, table moves during acquisition.
What 4 things should you check with the patient if IV contrast is required?
- Contraindications to IV contrast/ previous allergy
- Diabetic status
- History of kidney disease
- History of heart disease/ asthma
How do you position for a brain scan?
Place pads beside ears, Vertical centring light along MSP, Horizontal centring light at base of sinuses, Lateral laser light at level of EAM, Ensure symmetry,
How can you avoid irradiating the lens of the eye in a helical brain scan if you can’t tilt the gantry?
Tilt chin down
What are the kvp & mAs values for CT brain scan?
kVp: 120
mAs: 200-280
What needs to be included in a brain CT scan?
C1 to top of petrous ridge & petrous ridge to vertex
Why are coronal and sagittal reconstructions important?
They increase diagnostic accuracy in some cases.
Why use CT for suspected stroke?
To see the area & extent of stroke
What’s involved in a hemorrhagic stroke?
Blood vessel bursts
What’s involved in an ischaemic stroke?
Blood clot stops the flow of blood to an area of the brain.
How does a hemorrhagic stroke appear on a CT scan?
- Oval shaped hyperdensity on one side of brain
- Intra-axial location - M3 branch aneurysm
- Causes midline shift to left
How does an ischaemic stroke appear on a CT scan?
- Wedge-shaped hypodensity on one side.
- Occupies MCA vascular territory
- Causing midline shift to left
- Loss of grey/white matter interface & sulk pattern on right
- Obliteration of anterior horn of one of the lateral ventricles
Which is superior out of CT & MRI for demonstrating haemorrhage & bone changes in neoplasms?
CT
What does GCS stand for?
Glasgow coma scale
What are the clinical indications for a CT in relation to TBI?
- GCS < 13 initial assessment or GCS <15 2 hours post injury
- GCS 15 in presence of risk factors e.g. vomiting, age, amnesia, neurological deficit etc.
What’s a subdural haematoma?
Where bridging veins tear between skull & cerebrum.
What does a subdural haematoma look like?
Crescentic fluid collection between skull & cerebrum.
What causes an extradural haematoma?
Arterial tear
What does an extradural haematoma look like?
Biconvex, hyper dense & confined by the sutures.
What causes a subarachnoid haematoma?
Trauma/aneurysm rupture
What does a subarachnoid haematoma look like?
Blood in CSF spaces, basal cisterns, sylvian fissures.
CVA
SOL
Cerebrovascular accident
Space occupying lesion
ICH
EDH
Intracerebral haemorrhage
Extradural haematoma
GCS
GBM
Glasgow Coma Scale
Glioblastoma Multiforme
GSW
SAH/SDH
Gunshot wound
Subarachnoid haemorrhage
HI
FHx/FH
Head Injury
Family history
TIA
IV
Transient ischaemic attack
Intravenous
NC/C-
C+
Non-contrast
With/post-contrast
TBI
AVM
Traumatic brain injury
Arteriovenous malformation
