CT of Brain Flashcards
0
Q
What is the most common type of CT scan?
A
- multi-slice= good for resolution
1
Q
What is CT?
A
- series of X-rays in different angles
- produce series of crossed sectional images
- quick and no need for anaesthetics/ remove anything magnetic
2
Q
How can you recognise a film is CT?
A
- (very similar to x-ray)
- white is skull; black is CSF and look for Kv and mAs
3
Q
How can you tell from the CT film about the age of patient?
A
- older= ventricles dilate; calcification of choroid plexus; atrophy of brain tissues
4
Q
How does a normal X-ray look like?
A
- look for midline and symmetry
- high density= used to describe intense white (haemorrhage); low density= used to describe intense black (infarct)
5
Q
When do you use a plain CT and when do you use a CT with iv contrast?
A
- you usually use a plain CT anyway and if there’s a mass suspected, CT again with iv contrast
6
Q
Types of Haemorrhage
A
- Subarachnoid= in CSF spaces ( caused by aneurysm usually)
- Intracerebral= within parenchyma (peels dura off)
- Acute extradural= lens shaped
- Acute or chronic subdural= crescent shaped
- > extends across the cerebral hemisphere usually; differences between chronic and acute= chronic is darker in colour
7
Q
Why sometimes theres a black outlining the white intensity shown on CT (i.e. Haemorrhage)
A
- Because odema present
8
Q
How does an infarct look like on CT?
A
- high intensity (black in colour), usually caused by thrombus or an embolus
- acute: cause odema and mass effect; chronic: leads to volume loss and shrinkage
- usually looks well in the initial scan, can get worse within 24 hours
9
Q
How do you identify mass on CT scans?
A
- look for distortion to gyral-sulcal pattern
- may need iv contrast
- smooth= benign meningioma -> regular enhancement of colour
- irregular= maglinant astrocytoma -> has blood vessels attached
