nuclear imaging of the human brain - coma science group · nuclear imaging of the human brain...

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Nuclear imaging of the human brain

Steven Laureys

Coma Science GroupCyclotron Research Centre & Neurology Dept.University of Liège, Belgium

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Neuroimagingstructurefunction

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Neuroimaging: Modalities

Laureys et al Brain imaging In: Biological PsychiatryEd D’haenen, den Boer, Willner, John Wiley & Sons 2002 155-166

Structural– Computerized Tomography (CT)– Magnetic Resonance Imaging (MRI)

Functional– Positron Emission Tomography (PET)– Single Photon Emission CT (SPECT)– functional MRI (fMRI)– MR spectroscopy– EEG & Event-Related Potentials (ERP)– Magnetoencephalography (MEG)– near infrared spectroscopy (NIRS)

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Structure versus function

Laureys et al Brain imaging In: Biological PsychiatryEd D’haenen, den Boer, Willner, John Wiley & Sons 2002 155-166

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Angelo Mosso & Bertino

Forarm

Brain

“Pulsometer”

Frontalskull defect

Taken from Posner & Raichle, Images of Mind

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John Fulton & Walter K

Rest

Reading

occipitalskull defect over arterio-venous malformation

« It was not difficult to convince ourselves that when the patient suddenly began to use his eyes after a prolonged period of rest in a dark room, there was a prompt and noticeable increase in the intensity of his bruit… Activity of his other sense organs, moreover, had no effect upon his bruit. »

“Bruitometer”

Brain, 1828

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Positron Emission Tomography

http://en.wikipedia.org/wiki/Positron_emission_tomography

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disorders of consciousness | behavioural evaluation | electrophysiology | neuroimaging | methods, ethics & quality of life | perspectives

[18F]2-fluoro-2-deoxyglucose

FDG

in plasma

FDG

in tissueFDG-6-P

in tissue

k1

k2

k3

(k4 )

Three compartment model

k = rate constant fluorodeoxyglucose

FDG-6-phosphate

intracellular hexokinase

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PET - fMRI

6 mm30 s

2-5 mm5-8 s

Hemodynamic imaging

H215O PET

1-3 mm1 s

fMRI BOLD

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PET - fMRI PET radiotracers

Dopamine

Benzodiazepine

Serotonin

Histamine

Muscarinic cholinergic

Amyloid, Protein kinase C, monoamine oxidase...

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Statistical parametric mapping

www.fil.ion.ucl.ac.uk/spm

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Imaging consciousness

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Terry Schiavo °1963, vegetative 1990, † 2005

Neuroimaging of consciousness

« Beyond any doubt whatsoever, Terri is in a vegetative state »- Ronald Cranford MD, Neurology, Minneapolis, MN

« There is a great likelihood that Terri is in a minimally conscious state »- William Cheshire MD, Neurology, Mayo Clinic, Jacksonville, FL

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Disorders of consciousness

Laureys, Scientific American, 2007

PermanentMinimally Conscious

State

?

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Functional neuroimagingresting brain functionbrain activation studies

passive paradigmsactive paradigms

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Neuroimaging

www.comascience.orgLaureys, Owen & Schiff, Lancet Neurology, 2004 (sleep data from Pierre Maquet; anesthesia data from Mike Alkire)


Resting metabolism

FDG-PET

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Rudolf et al. Lancet 2000

11C-flumazenil PET

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Laureys, Maquet, Moonen, Encyclopedia of Neuroscience, 2007

Global metabolism

FDG-PET

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Laureys et al, New Encyclopedia of Neuroscience (Ed.) Larry Squire, in press

Regional changes

n=60

FDG-PET

www.comascience.orgLaureys, Owen and Schiff, Lancet Neurology, 2005


Consciousness area ?

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HMPAO-SPECT

Ictal-interictal P<0.01

Simple partial seizure n=6

Complex partial seizure n=8

Blumenfeld et al, Cerebral Cortex, 2004

Temporal lobe epilepsy

www.comascience.orgLaufs et al, Epilepsia 2006

Negative correlation with GSWD

Absence seizures

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Sleepwalking

Patient compared to 24 controls

Bassetti et al, Lancet 356 (2000) 484-5ECD-SPECT

Sleepwalking

www.comascience.orgSchnakers et al, JNNP in press

Pharmacological stimulation

amantadine amantadine

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Do they feel pain ?

GRIMACINGNO RESPONSE AWAKENING

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Laureys, Nature Reviews Neuroscience, 2006

Vegetative is not brain dead

H215O-PET

www.comascience.orgLaureys et al., Neuroimage, 2002


(n=15)

(n=15)

Cortical activation

www.comascience.orgLaureys et al., Neuroimage, 2002


Disconnected S1

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"…a (wo)men’s brain is a mystery...and even more so in this state."

Abla con Ella

Pedro Almodóvar

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Do they hear anything?

Laureys et al., Brain, 2000Boly et al, Archives of Neurology, 2004

www.comascience.orgLaureys et al., Neurology, 2004

Emotional processing

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www.comascience.orgBoly et al, NeuroImage 36 (2007) 979-92


TEN

NIS

NA

VIG

ATIO

NWhen thoughts become action

www.comascience.orgOwen, Coleman, Boly, Davis, Laureys and Pickard, Science, 2006


Active paradigms

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Conclusions

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Conclusion

• Need for objective markers of consciousness in comatose states• PET

• quantify resting metabolism• neuro-receptor studies• markers of neuronal death & neuronal plasticity

• fMRI• ‘activation’ studies

• Vegetative state : disconnection syndrome with dysfunction of fronto-parietal network of “higher order” cortices

• Minimally conscious state : intact pain & emotional perception

• Much more research is needed

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nuclear imaging of the human brain - coma science group · nuclear imaging of the human brain...

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