NEUR535 - Neuroimaging Flashcards
Learning Outcomes
* Identify the neuroimaging procedures that are used in Clinical
neuroscience
* Understand the mechanisms by which different neuroimaging
devices acquire their images
* Describe the advantages and disadvantages of each
neuroimaging device
* Understand the use of neuroimaging in behavioral neuroscience
research
What are the key general uses for neuroimaging?
- Disease Differentation
- Diagnosis
- Monitoring disease progression
- Monitor treatment outcomes
How is neuroimaging utilised in research?
- Highlighting the neuroanatomical an functional activity changes in the brain for psychological conditions
– Understanding pathophysiology of disease conditions in research
- Investigate treatament and therapy intervention effectiveness
6 key Forms of neuroimaging for cerebral changes in neurphsiology and neurpsychology research…?
– Electroencephalography (EEG)
– Computed Axial Tomography Scan (CT scan)
– Magnetic Resonance Imaging (MRI)
– Functional Magnetic Resonance Imaging (fMRI)
– Positron Emission Tomography (PET)
– Single Photon Emission Computed Tomography
(SPECT)
What is electroencephalography EEG used for in neuroscience?
Investigate brain electrical activity and cerebral changes
What is the mechanism of EEG ?
- Electrodes attached to scalp
- Measures cortical voltage fluctuations from ionic current flows within the neurons
- Collective neurons in an area
- Used less than 40 minutes at a time
What are 7 key conditions why an EEG is utilised?
- Sleep studies
- Epilepsy
- Coma
- Encephalopathies
- Tumours
- Stroke
- Brain death diagnosis
What are the EEG advantages and disadvantages?
Advantage:
- electrical localisation & strength
- Risk free
- Painless
- Cheap
- Precise time recordings
Disadvantage:
- Poor resolution
- Doesn’t record interior brain activity
What does CT scan stand for?
Computed axial tomography scan
How does a CT scan work?
- Utilize a series of x-rays applied from different directions
- uses a set of algebraic calculations to
estimate how much x-ray is absorbed by an
organ.
What kind of images do CT scans produce e.g. 3D, 2D, 4D?
2D
How are CT scans displayed?
Cross-sectional images or slices
What creates a whiter material on a CT scan?
Harder material will appear whiter in a CT scan e.g. bones
What are CT scans generally used to investigate?
- blood clots
- Intracranial bleeding
- Strokes
- Bone/vascular irregularities
- Brain tumours/cysts
- Tissue damage/swelling
- CNS trauma
- Ventricles e.g. hydrocephalus
- Herniated discs
- Epilepsies
- Encephalitis
- Spinal canal stenosis
How are CT scans used in neuroscience research?
Neurophysiological and neurophysological factors:
- Mental health disorders
- Issues post trauma
- Cognitive impairements
What are CT scan advantages?
- non-invasive/painless
- Quick (20 mins - 1hr)
- Images immediate
- Differentiating neurological disorders with similar characteristics
What are CT scan disadvantages?
- Expensive
Individuals who are:
- Obese or claustriphia
- Pregnancy
- Anxious/restless
- Contrast dye can have allergic reactions and unwanted side effects
What does MRI stand for?
Magnetic Resonance Imaging
What combination does an MRI use to create 2D or 3D images?
magnetic field and computer-generated radio waves
What mechanism does an MRI use to generate images?
temporary realignment of water molecules as a result of
the high magnetic field created around the body.
What is EEG amplitude measured in?
microvolts
What are the 4 main EEG wavelengths?
- Gamma
- Beta
- Alpha
- Theta
Can an MRI differentiate between bone, soft tissues, and fluid filled spaces?
Yes - based on water content
WHat are key conditions an MRI is referred for
Diagnosis and differentiation of CNS:
- Tumours
- Structural abnormalities
- Eyes
- Inflammation
- Infection
- Vascular irregularities
- Neuro-degenerative disorders
How are MRIs utilised in neuroscience research?
- Diagnostic marker for mental health
- Measuring effects of interventions
- Investigating strcutural abnormalities and functional changes
- Investigating treatment outcomes or resistance
- ## Personality changes
What are the advantages of an MRI?
- Safe
- High quality images
- High anatomical detail surface/subsurface structures
- Detects changes overtime due to directional capacity/precision
What are MRI disadvantages?
- More expensive
- Patients: medical devices e.g. pacemaker/metalics unable
- Obese/claustrophic
- Contrast dye side effects
What is the key mechanisms behind fMRI scans?
- Blood magnetic properties for blood flow to particular areas
- Change in magnetization between oxygen-rich/poor blood (active parts)
- Presents graphically by colour-coding to show strength of activation
- Entire brain and specific regions are identified
Why would you refer for an fMRI scan?
- Precise determination of brain regions
- Critical functions involving thought, speech, movement, sensation
- Brain tumour growth/function monitoring
- surgical planning
- radiation therapy
- Other surgical brain treatments
- Investigating psychological conditions
- Measure changes in treatments
What are the advantages of fMRI?
- Images of the brain every second
- Excellent precision
- High resolution
- Can depict brain activity with a region occuring simultaneously or sequentially
What are the disadvantages of fMRI?
- Longer procedure times
- Client must be still
- fMRI is expensive
- Confounded by other thought factors during the procedure causing other parts of the brain to become active
- Unable to identify brain receptors activated by neurotransmitters, drugs and potential treatment compounds
What does PET scan stand for?
Positron Emission Tomography
HOw does a PET scan predominantly work?
- Measures emissions from radioactively labelled chamicals that have been injected into the blood stream
- Uses the data to produce 2 or 3 dimensional images of the distribution of the chemicals throughout the brain
What do PET scans detect
radioactivity of Gamma rays as the compounds accumulate in different regions of the brain
What conditions would you generally choose for a PET scan?
- Highlight tumours and diseased tissue
- Where you need to determine blood flow of the brain
- Measure cellular and/or tissue metabolism
- Seizure disorders
- Memory disorders
- Brain changes post injury or drug abuse
- Differentiation of malignant and benign tumours
- Follow up from CT or MRI
- Measure treatment effectiveness
- Cortical changes for neuroassociated diseases
What are the advantages of PET scans?
- Allows different compounts to show blood flow
- Reviews brain oxygen consumption and glucose metabolism
- Essential for identifying strokes, gliomas, meningiomas, lymphomas, brain metastasis
- Specific for target therapy e.g. peptide receptor radionuclide therapy
- Superior resolution
- Hgih speed
What are the disadvantages of PET
- Limited to monitoring short tasks
- Radioactive exposure
- Expensive
What does SPECT stand for?
Single photon emission computd tomography (SPECT)
Is a SPECT scan using radioactive tracers?
yes
What is the most similar brain scan to SPECT?
PET scan
What does the SPECT scan test?
blood flow to issues to evaluate brain function
What type of imaging is a SPECT scan?
nuclear
What dimensional images does a SPECT construct?
2D & 3D
Which scan uses more gamma radiation; PET or SPECT?
PET:SPECT 2:1
Does a SPECT use radioavtive isotopes?
Yes
How is the radioactive isotope in PET and SPECT delivered
IV
What is the major difference upon use between SPECT and PET scans?
- SPECT can determine longer lasting brain functions
What is the general use of a SPECT scan?
- Follow-up for MRI to diagnose tumours, infections, degenerative spinal disease, stress fractures
SPECT in neuroscience research
What are the advantages of SPECT?
- Tracers of SPECT are longer lasting than those of PET
- Cheaper than PET
- Some scanners are linked with CT scans for CT and SPECT in one image session
What are the disadvantages of SPECT?
- More limited than PET
- Poor resolution to PET
- Longer time frames
