Nuclear imaging of the human brain

Transcription

1 Nuclear imaging of the human brain Steven Laureys Coma Science Group Cyclotron Research Centre & Neurology Dept. University of Liège, Belgium

2 Neuroimaging structure function

3 Neuroimaging: Modalities 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) Laureys et al Brain imaging In: Biological Psychiatry Ed D haenen, den Boer, Willner, John Wiley & Sons

4 Structure versus function Laureys et al Brain imaging In: Biological Psychiatry Ed D haenen, den Boer, Willner, John Wiley & Sons

5 Angelo Mosso & Bertino Forarm Pulsometer Brain Frontal skull defect Taken from Posner & Raichle, Images of Mind

6 John Fulton & Walter K occipital skull defect over arteriovenous malformation Bruitometer Rest «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.» Reading Brain, 1828

7 Positron Emission Tomography

8 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives [ 18 F]2-fluoro-2-deoxyglucose Three compartment model k 1 k 3 FDG in plasma k 2 FDG in tissue (k 4 ) FDG-6-P in tissue k = rate constant fluorodeoxyglucose FDG-6-phosphate intracellular hexokinase

9 Hemodynamic PET - imaging fmri 6 mm H 2 15 O PET 1-3 mm fmri BOLD 30 s 1 s 2-5 mm 5-8 s

10 PET - fmri PET radiotracers Dopamine Benzodiazepine Serotonin Histamine Muscarinic cholinergic Amyloid, Protein kinase C, monoamine oxidase...

11 Statistical parametric mapping

12 Imaging consciousness

13 Neuroimaging of consciousness Terry Schiavo 1963, vegetative 1990, 2005 «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

14 Disorders of consciousness Permanent Minimally Conscious State? Laureys, Scientific American, 2007

15 disorders of consciousness clinical evaluation electrophysiology neuroimaging ethics & quality of life conclusion Blink and you live Laureys et al., Progress in Brain Research, 2005

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17 Functional neuroimaging resting brain function brain activation studies passive paradigms active paradigms

18 Neuroimaging

19 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives Resting metabolism FDG-PET Laureys, Owen & Schiff, Lancet Neurology, 2004 (sleep data from Pierre Maquet; anesthesia data from Mike Alkire)

20 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives 11 C-flumazenil PET Rudolf et al. Lancet 2000

21 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives Global metabolism FDG-PET Laureys, Maquet, Moonen, Encyclopedia of Neuroscience, 2007

22 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives Regional changes FDG-PET n=60 Laureys et al, New Encyclopedia of Neuroscience (Ed.) Larry Squire, in press

23 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives Consciousness area? Laureys, Owen and Schiff, Lancet Neurology, 2005

24 Temporal lobe epilepsy Simple partial seizure n=6 Complex partial seizure n=8 HMPAO-SPECT Ictal-interictal P<0.01 Blumenfeld et al, Cerebral Cortex, 2004

25 Absence seizures Negative correlation with GSWD Laufs et al, Epilepsia 2006

26 Sleepwalking Sleepwalking Patient compared to 24 controls Bassetti et al, Lancet 356 (2000) ECD-SPECT

27 Pharmacological stimulation amantadine amantadine Schnakers et al, JNNP in press

28 Functional neuroimaging resting brain function brain activation studies passive paradigms active paradigms

29 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives Do they feel pain? NO RESPONSE AWAKENING GRIMACING

30 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives Vegetative is not brain dead H 2 15 O-PET Laureys, Nature Reviews Neuroscience, 2006

31 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives Cortical activation (n=15) (n=15) Laureys et al., Neuroimage, 2002

32 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives Disconnected S1 Laureys et al., Neuroimage, 2002

33 Abla con Ella " a (wo)men s brain is a mystery... and even more so in this state." Pedro Almodóvar

34 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives Do they hear anything? Laureys et al., Brain, 2000 Boly et al, Archives of Neurology, 2004

35 Emotional processing Laureys et al., Neurology, 2004

36 Functional neuroimaging resting brain function brain activation studies passive paradigms active paradigms

37 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives When thoughts become action NAVIGATION TENNIS Boly et al, NeuroImage 36 (2007)

38 disorders of consciousness behavioural evaluation electrophysiology neuroimaging methods, ethics & quality of life perspectives Active paradigms Owen, Coleman, Boly, Davis, Laureys and Pickard, Science, 2006

39 Conclusions

40 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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