Neuroimaging Flashcards
(28 cards)
What are the advantages and disadvantage of EEG ?
Advantages:
- good time resolution
- portability
- affordable
- silent (can be done during auditory processing)
- can be combined with other methods
Disadvantages ?
- low spatial resolution
- artifacts
What are the advantages and disadvantages of MEG ?
Advantages:
- good time resolution
- reduced preparation time
- signal unaffected by skull and scalp
Disadvantages:
- expensive
- low spatial resolution
- subject cannot move
- not portable
- sensitive only to neurons in sulci
What can cause artifacts on EEG ?
- Eye lid movement
- scalp muscle activity
- pacemakers
- movement (= change in impedance)
- electrode-wire contact
- poor grounding
- sweating
What are brain oscillations ?
Rhythmic fluctuations of repeated electrical activity generated by the activity of neurons.
Can be spontaneous or in reaction to a stimulus.
What is neurofeedback training ?
Expected or desired aspects of cortical and subcortical activation can be achieved or modified through sensory (visual and auditory) stimulation, controlled by a biofeedback system that rely on EEG information.
What are the types of neurofeedbacks ?
- univariate : blood oxygen level dependent
- decoded : multi voxel activity pattern
- connectivity : functional connectivity between regions
For which conditions has NFT been proven efficient ?
- ADHD
- ADH
- epilepsy
- neurocognitive disorders
- ABI in connection with facilitation, sensory augmentation and functional training
What are the advantages of MRI compared to CT ?
- no use of ionizing radiation
- contrasts have less side effects
- comparable resolution but not the same tissues
- more detailed even without contrast
What are the disadvantages of MRI compared to CT ?
- Claustrophobic patients
- limitation to weight and size of patient
- very noisy
- long time of procedure (not suitable for emergencies)
- sequential (no generalization possible)
What are the characteristics of T1 weighted image ?
White matter appears brighter than grey matter:
Hypointense signal:
- cerebro spinal fluid
- edema
- tumor
- infection
- inflammation
- hemorrhage
- calcification
Hyper intense signal:
- chronic hemorrhage
- fat
- protein rich fluid
- slow flowing blood
- contrast
My best friend is pretty cool
- melanin
- blood
- fat and slow blood flow
- proteins and paramagnetic substances
- cholesterol and contrast
What are the characteristics of T1 weighted image ?
White matter appears brighter than grey matter:
Hypointense signal:
- cerebro spinal fluid
- edema
- tumor
- infection
- inflammation
- hemorrhage
- calcification
Hyper intense signal:
- chronic hemorrhage
- fat
- protein rich fluid
- slow flowing blood
- contrast
What will cause unbalanced delta waves ?
Slowest in the human brain
Too much:
Dépression
Too little:
Sleep disorders and dissociation
What will cause unbalanced Theta waves ?
Too much:
Lack of focus
Too little:
Memory disorders
What will cause unbalanced alpha waves ?
Strongest EEG brain signal
Too much:
Anxiety
Too little:
Exhaustion
What will cause unbalanced beta waves ?
Too much:
Obsession
Too little:
Dépression and anhedonia
What will cause unbalanced SMR waves ?
Sensorimotor rhythm
Too much:
Dépression
Too little:
Attention disorders
What will cause unbalanced gamma waves ?
Fastest brain wave
Too much:
Paranoïa
Too little:
Reasoning and perceptual deficits
What are the characteristics of T2 weighted images ?
Grey matter appears brighter than white matter.
Hypointense signal will reveal: CSF, edema, infection, inflammation, subdurral or subacute haemorrhage and calcification.
Hyperintence signal will reveal: calcification, fibrous tissue, iron and melanin.
What is FLAIR used for ?
Fluid Attenuated Inversion Recovery.
Efficient in the evaluation of vascular injuries, SDH and multiple sclerosis.
What are the purposes of T1WI ?
- Intracerebral bleeding
- structures with high fat concentration
- small anatomical details
What are the purposes of T2WI ?
- Edema
- Demyelination
- Infarction
- Chronic haemorrhage
What are the purposes of FLAIR ?
- Edema
- Demyelination (most specific)
- Periventricular and pericortical hemorrhage
What are commissural fibers ?
Connection between hemispheres.
- Corpus callosum
- Anterior commissure
- Fornix
What are the projection fibers ?
Connection from/to the cortex:
- optic and acoustic fibers
- thalamocortical fibers
- internal capsule
- cortico pontine
- corticospinal tract
