21499028
| Question | Answer |
| MRI machines | - Come in different magnetic field strengths, measured in teslas. - The higher the tesla, the more sensitive the scanner - Used to observe the progression of cerebral loss in dementia; can quantify and identify tissue loss. - scan is built up line by line, nowadays blade by blade to avoid motion artefacts - Can be used to identify differences in hippocampal volume in psychiatric disorders, in an attempt to quantify these illnesses. EG a difference in shape in schizophrenia - AI and computer regulation used in conjunction, finding differences between patients and controls - Can diagnose autism with over 90% accuracy - structured MRI, diffusion MRI and CSF amyloid can be combined to predict conversion to alzeimers, 2 years in advance with 91% accuracy |
| MRI machines pros and cons | Pros - have superseeded the CAT scanner - high resolution - quick; image in a couple secons Cons - Quite claustrophobic - motion artefacts if ppl move - Not good if patient has internal metal due to high magnetic field |
| MRI and ARMS (at risk mental states) | - 15% of those with relatives that have psychotic disorders have 'ARMS'; 'soft' psychotic features that can develop into psychosis. - If this can be identified, we can help protect the brain without the need for meds with bad side effects - Brain scans see the changes in the brain over time, can identify if it is headed to full blown psychosis. - uses proton mr spectrometry |
| MRI for pre-clinical investigation | - safe even for mice - this allows for looking at animal models of stroke etc - image can be looked at/sectioned along different axis |
| Mechanism | - uses 'free diffusion' in an isotrophic enviroment - using fibre tracts to restrict diffusion in an anisotrophic enviroment - these can build up a picture of the whole brain |
| MRI for investigating the brain | - Can identify white, matter grey matter, fluid filled areas of the brain, where water is bound to myelin, MS plaques. Allows for treatments to be developed. - Can be used to scan brain of baby in utero to identify neuronevelopmental diseases |
| fMRI | - mechanism by which we can look at brain activity using BOLD contrast imaging. - BOLD: Blood, Oxygen, Dependent, Level, Contrast - looks at oxygenation levels of blood to identify different brain states - builds up slices of brain to see what is happening over a few minutes - can be used in somatic sensory stimulation or in pain experients - can be used to diagnose cognitive impairment - Clint Eastward paradigm; 'shoot first ask questions later' |
| Cognitive impairment | - a salient feature of almost all mental illnesses - no drug to treat it - Morris water maze; where rats/mice are trained to find a platform underwater. May serve as a proxy for cognitive impairment in humans - Can be done in humans using fMRI; AI arena, fMRI used to observe which areas of the brain are active during the task |
| Atrial spin labelling (cASL) | - allow us to quantify cerebral blood flow (CBF) changes - results in scans where we can see blood from the brain |
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