Imaging of Alzheimer's and Parkinson's Diseases

Question 1

State some pathological features of AD

Answer 1

Extracellular amyloid plaques, intracellular neurofibrillary tangles, neuritic plaques, astrocytosis

Question 2

Where does plaque deposition in AD start?

Answer 2

Base of the forebrain

Question 3

Where does neurofibrillary tangle deposition in AD start?

Answer 3

Hippocampus

Question 4

Name a PET tracer for AD

Answer 4

11C-PIB (N-methyl[C-11]2-[4’-methylamino-phenyl]-6-hydroxyl-benzothiazole); 11F-FDG

Question 5

What does 11C-PIB bind to?

Answer 5

Fibrillar amyloid

Question 6

Name a part of the brain where fibrillar amyloid is not deposited in AD

Answer 6

Cerebellum

Question 7

Define mild cognitive impairment

Answer 7

Impaired memory function for age and education but preserved general cognitive function

Question 8

What percentage of mild cognitive impairment patients have converted to Alzheimer’s after 3 years?

Answer 8

80%

Question 9

How does 11C-PIB uptake change as AD progresses?

Answer 9

No significant change - suggesting there is no correlation between amyloid load and cognitive performance

Question 10

What does 18F-FDG detect?

Answer 10

Glucose metabolism

Question 11

How does 18F-FDG uptake change as AD progresses?

Answer 11

Slight decrease

Question 12

State the consensus guidelines for diagnosis of Lewy body dementia

Answer 12

Dementia before parkinsonism or within 12 months or parkinsonism and associated with hallucination and confusion

Question 13

Describe the symptoms of Parkinson’s disease dementia

Answer 13

Impairment of short-term recall, attention, visuospatial function, and executive function, with personality and behavioural changes, confusion, and hallucinations

Question 14

Describe the pathology associated with Lewy body dementia

Answer 14

Cortical Lewy bodies, neurofibrillary tangles, degeneration of subcortical nuclei (substantia nigra, nucleus basalis of Mynert, locus coeruleus)

Question 15

Define subjective cognitive impairment

Answer 15

Perceived memory problems with normal performance on cognitive testing

Question 16

Describe the stages involved in microglia activation

Answer 16

Ramified (R-stage) -> activation signal -> withdrawal (W-stage) -> transitional (T-stage)-> motile (M-stage) -> locomotory (L-stage)

Question 17

Describe the actions of activated microglia

Answer 17

Protein expression, proliferation, cytokine secretion, transformation into macrophages

Question 18

Name a PET tracer which binds to activated but not resting microglia

Answer 18

PK11195

Question 19

Describe the relationship between microglial activation and AD

Answer 19

An increase in microglial activation over time correlates with a decline in cognitive function

Question 20

What happens to CSF tau and amyloid-beta in AD?

Answer 20

CSF tau increases, whereas amyloid-beta decreases as it is sequestered in the brain

Question 21

Name a PET tracer for tau

Answer 21

T807

Question 22

Describe the relationship between tau load and MMSE performance

Answer 22

As tau load increases, MMSE performance decreases