CT scanning rotating xray slices
black is not dense white is dense
you can use neural ct scans to see necrosis and bleeding
Bleeds
extradural bleed ususally acute and therefore white due to the presence of iron and protein
subdural bleed usually black as it is often chronic and so iron and protein has been resorbed
subarachnoid looks like white sulci and id often acute often from arteryies around the circle of willis
tumours
using iv iodine contrast you can see the shape of tumours better, and disticguish from necrosis or bleed
MRI
T1 is anaatomy sensitive whater is dark -/+ gadolinium contrast
T2 is fluid sensitive water is white
flair for MS DWI for early infarcts ADC map