Brain Imaging Lec 11 Flashcards
CT enhances visualization of
Bony anatomy
Acute hemorrhage or stroke
Generalized atrophy
Elements with high atomic numbers show up better
CT advantages
Fast Initial screening and assessment Bone imaging Hemorrhage detection Pt flexibility
CT disadvantages
Use of Xray
Not as good for soft tissue as MRI
Low spatial resolution
Head CT
Infarction- hypodense Tumors- swelling or edema surrounding Calcifications- hyperdense Hemorrhage- hyperdense Bone trauma- hyperdense
MRI measurements provided
Brain structure
Vasculature
Chemical structure
Fiber tracts
MRI disorders
Neoplasm
Demyelination- MRS
Degenerative diorders- cortical atrophy
MRI advantages
High spatial resolution
No radiation
Excellent contrast
MRI disadvantages
Long study time
No ferromagnetic or electronic devices
Claustrophobic
Tesla
Increase resolution and signal/noise
- T1- fast RF pulse
- T2-slow RF pulse- water or path tissue
MRS
Separates our components of chemical mixtures in brain
-used to compare normal to tumor tissue in brain
Diffusion tensor imaging
Visualization of white matter
water movement along axis
smaller coefficient- pathology
- can measure myelin integrity
fMRI
measure brain fxn in vivo
measure blood oxygen during activity
PET Measurements provided
Perfusion
Metabolism
NT integrity
PET disorders
Psychiatric/addictive/degenerative
epilepsy
PET advantages
Functional imaging
Physiological variables can be determined
