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.
