Brain Imaging Lec10 Flashcards
____ imaging invovles a rotating x ray beam
CT
rate of attenuation with a CT varies by
tissue
Beam attenuates (ie weakens) as it passes through brain tissue
what is detected with a CT?
radiodensity information
used to reconstruct 3d image
advantages to CT
bone imaging
hemorrhage detection
patient flexibility
disadvantages to CT
- ionizing radiation
- not as good for soft tissue
- lower spatial resolution
with MRI, Rapid repetitions of ___ enhance gray-white contrast
RF pulse
with MRI, Infrequent RF pulses enhance___
water signal
advantages to MRI
- high spatial resolution
- no radiation
- excellent contrast
- functional/chemical imaing avail.
disadvantages to MRI
- long study duration
- no ferromagnetic or electronic devices
- small as hell – claustrophobia
with Magnetic resosnance spectroscopy you look at the
chemical structure of the brain
on MRS choline indicates
demyelination
on MRS, creatine indciates
glial
on MRS, lactate indicates
ischemia
on MRS, NAA indicates
neuronal marker
____ involves measuring water diffusion
DTI: Diffusion Tensor Imaging
DTI: Diffusion Tensor Imaging invovles measuring water diffusion along different orientatations within ___
axes
fMRI in vivo measures
BOLD, blood-oxygen-level dependent, signals at baseline vs.
! experimental conditions
limitations of FMRI includes
spatial and temporal resolution
what does PET involves?
PET: radioactive tracer incorporated into a biologically active molecule (ex. Glucose, oxygen, dopamine transporters)
disadvantages of PET?
- need a cyclotron to make radioisotope
- radiation exposure
what are 5 applications of imaging mdoalities?
- map nml brain development
- alzheimers disease
- image guieded neurosurgery
- schizopehnia
- pain )in high vs. low sensitvity pts)
advantages of pet?
functional imaging
physiological variables can be determined
to study brain structure what could you use
CT or MRI
what to use when looking at vascualture?
MRI