L23: imaging the brain Flashcards
how to image newborns brain
ultrasound
why can you ultrasound newborns but not adults
fontanelles are transparent to sound waves
what does X-ray show best
bone
3 clinical used of X-ray
Skull fracture
surgery
haemorrhage
what does a CT scan use
X-ray
what is the clinical use of a CT scan
imaging structures associated with the brain (but not the brain itself)
What can enhance different parts of the brain in MRI
different tuning
what does MRI show well
soft tissue
how does MRI work
external magnetic field looks at the mass charge and spin of protons
what are the different proton environments in the brain
water, fat
with T1 weighted MRI what is grey
grey matter
with T1 weighted MRI what is white
white matter
with T1 MRI is bone visible
No
what colour are the ventricles in T1 weighted MRI
black
what colour is the outside scalp in T1 MRI
bright white (highly vascularised)
in T2 what colour is white matter
dark
in T2 what colour is grey mater
light
what colour are ventricles in T2
light
what method gives you a 3D reconstruction of blood vessels
MRI angiography
3 chemicals you can measure in magnetic resonance spectroscopy
- choline
- N-acetylaspartate
- Lactate
what does choline measure
cell density/ division
are tumours high in choline
yes
what does N-acetylaspartate measure
normal neural function
are tumours high in N-acetylaspartate
No - low in tumours
what is lactate a product of
glycolysis
why do tumours have more lactate
as they work anaerobically
PET=
positron emission tomography
what does an EEG measure
neural activity in the brain
what disease is ECoG used for
epilepsy
what does ECoG do
localises activity if the person is already having surgery to remove this part of brain
what does functional MRI measure
blood oxygen level
