Dementia: MRI Flashcards
Main structure involved in dementia?
Hippocampus
Purpose Coronal oblique T1W images in dementia?
-assess medial temporal lobe and hippocampal atrophy
purpose FLAIR images dementia?
- assess global cortical atrophy
- vascular white matter hyper intensities
- infarctions
purpose T2W images dementia?
-infarctions (esp lacunar in thalamus, BG)
When CT over MRI in dementia work up?
- if MRI contraindicated
- when only seek to r/o surgically treatable cause of cognitive decline
Initial step in MR evaluation for dementia?
EXCLUDE OTHER TREATABLE CAUSES!
- subdural
- tumours
- hydrocephalus
AD specific MR features?
- MTA: medial temporal lobe atrophy
- parietal atrophy
FTLD (frontotemporal lobar degeneration) specific MR features?
asymmetric frontal lobe atrophy and atrophy of the temporal pole
VaD (vascular dementia) specific MR features?
- global atrophy
- diffuse white matter lesions, lacunas, strategic infarcts
What are strategic infarcts?
infarcts in regions involved in cognitive function
MR fx Lewy Body Dementia?
Usually no specific abnormalities (cf other forms)
Approach to MR for dementia?
1. Exclude treatable causes then assess for: 2. Global atrophy 3. Focal atrophy 4. Vascular disease (infarcts, white matter lesions, lacunes)
GCA scale for global cortical atrophy?
- No cortical atrophy
- Mild atrophy: opening of sulk
- Mod atrophy: vol loss of gyri
- Severe: ‘knife blade’ atrophy
How are white matter lesions graded?
Fazekas scale for WM lesions
What do white matter hyper intensities (WMH) and lacunes indicate?
WMH and lacunes generally viewed as evidence of small vessel disease.
Frequently observed as evidence of small vessel disease
