Imaging Degenerative Imaging Degenerative Diseases of the Brain Diseases of the Brain

Cathleen KouvoloCathleen Kouvolo

Alzheimer’s DiseaseAlzheimer’s Disease

Parkinson’s DiseaseParkinson’s Disease

Huntington’s DiseaseHuntington’s Disease

Pick’s DiseasePick’s Disease

Alzheimer’s DiseaseAlzheimer’s Disease Most common cause of dementiaMost common cause of dementia Defective processing of amyloid precursor Defective processing of amyloid precursor

proteinprotein Affects hippocampus/parahippocampal cortex, Affects hippocampus/parahippocampal cortex,

cerebral cortexcerebral cortex Dementia, anxiety, hallucinations, delusions, Dementia, anxiety, hallucinations, delusions,

tremortremor Dx is clinical; MR used to rule out other causes Dx is clinical; MR used to rule out other causes

of dementiaof dementia Tx: cholinesterase inhibitors; Tx: cholinesterase inhibitors;

antidepressants/antipsychoticsantidepressants/antipsychotics

Alzheimer’s – MR/CTAlzheimer’s – MR/CT

CT- Diffuse cerebral atrophy, enlarged CT- Diffuse cerebral atrophy, enlarged ventricles and widened sulciventricles and widened sulci

T1 MR- Medial temporal lobe atrophy T1 MR- Medial temporal lobe atrophy (amygdala, hippocampus, parahippocampal (amygdala, hippocampus, parahippocampal gyrus)gyrus)

T1 weighted MRT1 weighted MR

ControlControl Alzheimer’sAlzheimer’s

Alzheimer’s – SPECT/PETAlzheimer’s – SPECT/PET

SPECT- Temporoparietal hypoperfusion SPECT- Temporoparietal hypoperfusion (especially in medial temporal lobes)(especially in medial temporal lobes)

PET- decreased glucose metabolism in PET- decreased glucose metabolism in frontal, parietal, temporal regionsfrontal, parietal, temporal regions

SPECTSPECT

Alzheimer’sAlzheimer’s

Parkinson’s DiseaseParkinson’s Disease

Hypokinetic disorderHypokinetic disorderLoss of dopaminergic neurons in substantia Loss of dopaminergic neurons in substantia

nigra (pars compacta)nigra (pars compacta)Pill-rolling tremor, cog-wheel rigidity, Pill-rolling tremor, cog-wheel rigidity,

bradykinesia, shuffling gait, mask-like faciesbradykinesia, shuffling gait, mask-like faciesDx: clinical after other etiologies ruled outDx: clinical after other etiologies ruled outTx: levodopa/carbidopa, anticholinergics, Tx: levodopa/carbidopa, anticholinergics,

amantadine; surgery for refractory casesamantadine; surgery for refractory cases

Parkinson’s – MR/CTParkinson’s – MR/CT

Diffuse atrophy and enlarged ventricles Diffuse atrophy and enlarged ventricles seen on CTseen on CT

Decreased pars compacta width Decreased pars compacta width (substantia nigra) may be evident on MR(substantia nigra) may be evident on MR

T2 weighted MRT2 weighted MR

ControlControl Parkinson’sParkinson’s

Parkinsons - PETParkinsons - PET

FDG- Similar distribution of hypoperfusion FDG- Similar distribution of hypoperfusion to that of Alzheimer’s (temporoparietal to that of Alzheimer’s (temporoparietal region) region)

Fluorodopa- Less uptake in pars compacta Fluorodopa- Less uptake in pars compacta in severe clinical disease as compared to in severe clinical disease as compared to mild disease mild disease

Huntington’s DiseaseHuntington’s Disease

CAG triplet repeat expansion in CAG triplet repeat expansion in huntingtinhuntingtin (HD) gene(HD) gene

Loss of spiny neurons, atrophy of striatum Loss of spiny neurons, atrophy of striatum (especially caudate nucleus)(especially caudate nucleus)

Choreiform movements, ataxic gait, facial Choreiform movements, ataxic gait, facial grimacing/lip smacking, dementiagrimacing/lip smacking, dementia

Dx: MR and positive family historyDx: MR and positive family historyTx: supportiveTx: supportive

Huntingtons – MR/CTHuntingtons – MR/CT

CT and T1 MR- caudate atrophyCT and T1 MR- caudate atrophy

T2- increased intensity in caudate and T2- increased intensity in caudate and putamen (due to gliosis); decreased putamen (due to gliosis); decreased intensity in globus pallidus (due to iron intensity in globus pallidus (due to iron deposition)deposition)

CTCT

ControlControl Huntington’sHuntington’s

Huntington’s - PETHuntington’s - PET

PET FDG- hypoperfusion of caudate PET FDG- hypoperfusion of caudate nucleusnucleus

May be evident before MR or CT changesMay be evident before MR or CT changes

Pick’s DiseasePick’s Disease

Defect in tau proteinDefect in tau protein Frontal and temporal lobes involvedFrontal and temporal lobes involved Symptoms similar to Alzheimer’s disease, Symptoms similar to Alzheimer’s disease,

greater personality change as compared to greater personality change as compared to memory lossmemory loss

Younger age of onset (compared to Alzheimer’s Younger age of onset (compared to Alzheimer’s disease)disease)

Dx: MRDx: MR Tx: Cholinesterase inhibitors not helpful, Tx: Cholinesterase inhibitors not helpful,

serotonergic agents may help with behaviorserotonergic agents may help with behavior

Pick’s – MR/CTPick’s – MR/CT

CT- Frontotemporal atrophyCT- Frontotemporal atrophy

MR- Sulcal widening, ventricular MR- Sulcal widening, ventricular enlargement, widening on lateral sulcus enlargement, widening on lateral sulcus (sylvian fissure), atrophy of insula, inferior (sylvian fissure), atrophy of insula, inferior frontal/superior. frontal/superior.

CTCT

ControlControl Pick’sPick’s

Pick’s - SPECTPick’s - SPECT

(Frontal variant) Hypoperfusion in (Frontal variant) Hypoperfusion in ventromedial frontal regionventromedial frontal region

(Lateral variant) Hypoperfusion in one/both (Lateral variant) Hypoperfusion in one/both temporal lobes and anterolateral temporal temporal lobes and anterolateral temporal lobe atrophy (sparing of hipppocampal lobe atrophy (sparing of hipppocampal formation)- left more affected than rightformation)- left more affected than right

SPECTSPECT

Pick’sPick’s

Summary of BuzzwordsSummary of Buzzwords

Alzheimer’s- medial temporal lobeAlzheimer’s- medial temporal lobe

Parkinson’s- substantia nigraParkinson’s- substantia nigra

Huntington’s- caudate nucleusHuntington’s- caudate nucleus

Pick’s- frontotemporal lobesPick’s- frontotemporal lobes

ResourcesResources

University of Virginia: Introduction to Head CT; University of Virginia: Introduction to Head CT; http://www.med-ed.virginia.edu/courses/rad/headct/index.html

Goetz: Textbook of Clinical Neurology, 2nd ed Goetz: Textbook of Clinical Neurology, 2nd ed Basic Clinical Neuroanatomy, Williams and Basic Clinical Neuroanatomy, Williams and

WilkinsWilkins Boards and Wards, 2Boards and Wards, 2ndnd ed, Lippincott Williams ed, Lippincott Williams

and Wilkinsand Wilkins