Transcript Imaging Degenerative Diseases of the Brain

Imaging Degenerative
Diseases of the Brain
Cathleen Kouvolo
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Alzheimer’s Disease
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Parkinson’s Disease
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Huntington’s Disease
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Pick’s Disease
Alzheimer’s Disease
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Most common cause of dementia
Defective processing of amyloid precursor
protein
Affects hippocampus/parahippocampal cortex,
cerebral cortex
Dementia, anxiety, hallucinations, delusions,
tremor
Dx is clinical; MR used to rule out other causes
of dementia
Tx: cholinesterase inhibitors;
antidepressants/antipsychotics
Alzheimer’s – MR/CT
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CT- Diffuse cerebral atrophy, enlarged
ventricles and widened sulci
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T1 MR- Medial temporal lobe atrophy
(amygdala, hippocampus, parahippocampal
gyrus)
T1 weighted MR
Control
Alzheimer’s
Alzheimer’s – SPECT/PET
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SPECT- Temporoparietal hypoperfusion
(especially in medial temporal lobes)
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PET- decreased glucose metabolism in
frontal, parietal, temporal regions
SPECT
Alzheimer’s
Parkinson’s Disease
Hypokinetic disorder
 Loss of dopaminergic neurons in substantia
nigra (pars compacta)
 Pill-rolling tremor, cog-wheel rigidity,
bradykinesia, shuffling gait, mask-like facies
 Dx: clinical after other etiologies ruled out
 Tx: levodopa/carbidopa, anticholinergics,
amantadine; surgery for refractory cases
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Parkinson’s – MR/CT
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Diffuse atrophy and enlarged ventricles
seen on CT
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Decreased pars compacta width
(substantia nigra) may be evident on MR
T2 weighted MR
Control
Parkinson’s
Parkinsons - PET
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FDG- Similar distribution of hypoperfusion
to that of Alzheimer’s (temporoparietal
region)
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Fluorodopa- Less uptake in pars compacta
in severe clinical disease as compared to
mild disease
Huntington’s Disease
CAG triplet repeat expansion in huntingtin
(HD) gene
 Loss of spiny neurons, atrophy of striatum
(especially caudate nucleus)
 Choreiform movements, ataxic gait, facial
grimacing/lip smacking, dementia
 Dx: MR and positive family history
 Tx: supportive
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Huntingtons – MR/CT
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CT and T1 MR- caudate atrophy
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T2- increased intensity in caudate and
putamen (due to gliosis); decreased
intensity in globus pallidus (due to iron
deposition)
CT
Control
Huntington’s
Huntington’s - PET
PET FDG- hypoperfusion of caudate
nucleus
 May be evident before MR or CT changes
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Pick’s Disease
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Defect in tau protein
Frontal and temporal lobes involved
Symptoms similar to Alzheimer’s disease,
greater personality change as compared to
memory loss
Younger age of onset (compared to Alzheimer’s
disease)
Dx: MR
Tx: Cholinesterase inhibitors not helpful,
serotonergic agents may help with behavior
Pick’s – MR/CT
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CT- Frontotemporal atrophy
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MR- Sulcal widening, ventricular
enlargement, widening on lateral sulcus
(sylvian fissure), atrophy of insula, inferior
frontal/superior.
CT
Control
Pick’s
Pick’s - SPECT
(Frontal variant) Hypoperfusion in
ventromedial frontal region
 (Lateral variant) Hypoperfusion in one/both
temporal lobes and anterolateral temporal
lobe atrophy (sparing of hipppocampal
formation)- left more affected than right
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SPECT
Pick’s
Summary of Buzzwords
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Alzheimer’s- medial temporal lobe
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Parkinson’s- substantia nigra
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Huntington’s- caudate nucleus
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Pick’s- frontotemporal lobes
Resources
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University of Virginia: Introduction to Head CT;
http://www.meded.virginia.edu/courses/rad/headct/index.html
Goetz: Textbook of Clinical Neurology, 2nd ed
Basic Clinical Neuroanatomy, Williams and
Wilkins
Boards and Wards, 2nd ed, Lippincott Williams
and Wilkins