neuro imaging Flashcards
(14 cards)
what is fMRI
Functional MRI (fMRI) Functional MRI is a type of MRI scan that can show which areas of your brain are most active.
- SEEING ACTIVITY OF BRAIN BASED ON FLOW OF deoxygenated/oxygenated blood in brain during activity
e.g can be used to find activation regions of brain correlating to a body part
compare the level of detail and the time taken b/w structured and functional MRI
STRUCTURED:
- high detail
- whole brain takes 3 mins
fMRI:
- low detail
- whole brain takes 3/2 seconds
why is an fMRI much faster and low in detail than structured MRI
- anatomy is not of interest (only activity) so time can be decreased = low resolution
what type of sequence is used in fMRI
EPI
explain how the image from fMRI differers to any other MRI image
it is seen in ‘neurological orientation’
so the right of the image is ACTUALLY the right side etc
what is DTI
diffuse tensor imaging (DWI imaging of brain)
what is an FA map
gives direction of restricted diffusion
how does an FA map give direction of diffusion
through FA colour map (FA-c)
- high signal on FA map = high isotopic diffusion (in all direction)
what are the colours for different orientations on an FA map
anterior - posterior = green
left to right = red
head to toe = blue
what property of molecules does spectroscopy (nMRI) use
chemical shiftq
explain chemical shift
electron clouds of protons in fat is larger so it is less affected by external magnetic field compared to water so its precession is slower/less affected by lamour freq
how does spectroscopy identify whether a mass is benign or cancerous for example
spectroscopy can analyse the chemical components of masses based on their chemical shift
lipid filled tumours and amino acids have very similar chemical shifts (0.8-1.2ppm) , how would spectroscopy go about identify either or
invert the graph/spectrum and AA should invert down at 135ms but tumour filled lipids won’t
what 2 chemicals will not be found in tumours
acetate and succinate
