fMRI and MR Spectroscopy

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fMRI and MR Spectroscopy
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BOLD

• BOLDBlood Oxygenation Level Dependant contrast
• Neurons at work use oxygen (carried by
  hemoglobin)
• 1-5 s. delay, peaks at 4-5 s.
• T2 or T2 contrast
• 2-4 mm spatial resolution
• 1-4 s. temporal resolution

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fMRI exam

• High resolution image of brain taken
• Series of scans over time
• Lower resolution
• T2 or T2 weighted
• Subject performs task, rests, performs task,
  rest, etc.
• Task can be visual, auditory, sensory, cognitive
• Statistical analysis performed

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Activated Regions
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3D Reconstruction
http//www.fmrib.ox.ac.uk/fmri_intro/trans_anim.gi
f
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Stroop Test

• http//www.david.tam.name/SelfTests/StroopEffects.
  html
• http//www2.b3ta.com/clickthecolour/
• http//www.pbs.org/wgbh/nova/everest/exposure/stro
  optest.html
• Results
• http//spnl.stanford.edu/healthy_brain/studies/hb_
  study_03.htm

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Other Cognitive tests

• http//www.cogtest.com/int_test/GoNoGoFlash1.html
• Face recognition results
• http//www.perceptionandaction.com/pdf/publication
  s/MarottaGenoveseBehrmann-2001-002.pdf

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MRS

• Image 1H NOT in water
• Large voxel
• Molecules have distinct RFs
• chemical shift distance from RF of water
• Supress water signal to see other signals

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Chemical Shift

• Area under peak gives concentration

http//www.mrispectroscopy.com/mrs.htm
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Cases
http//www.mrispectroscopy.com/Case_list.htm