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Cerebrospinal Fluid Flow Dynamics and
The Glymphatic System
Geir Ringstad, MD PhD
Senior Consultant Neuroradiologist Head, Neuroimaging Research Group
Oslo University Hospital, Norway
ECNR 2021
Disclosures / Conflicts of Interest
• Speaker for Bayer
• Chairman and share holder, BrainWideSolutions AS
Ringstad et al. (JCI Insight, 2018) Ringstad et al. (Brain, 2017)
Science, 2020
Glymphatic failure as common pathway for proteinopathies?
JCI Insight, 2018
Delayed clearance of CSF tracer in iNPH
Ringstad et al. JCI Insight, 2018
Ref, 24h iNPH, 24h
Glymphatic system
Iliff et al. (Sci Transl Med, 2012)
Meningeal lymphatics
Louveau et al. (Nature, 2015)
Da Mesquita et al. (Neuron, 2018)
Glymphatic clearance depends on CSF (lymphatic) clearance
Romanova et al. (bioRxiv, 2019)
Lymphatic ligation accelerates Alzheimer’s pathology in meninges & cognitively important brain regions
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3 h 24 h
T1 «black blood» T1 «black blood»
FLAIR
The parasagittal dura (PSD)
From : Fox R et al. Anatomic details of intradural channels in the parasagittal dura: A possible pathway for flow of cerebrospinal fluid
(Neurosurgery, Vol. 39, No.1, July 1996)
C: Intradural channels
T1-BB pre T1-BB 3 h
T1-BB 6 h T1-BB 24 h T1-BB 48 h
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143 %
250 %
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491 %
414 %
583 %
299 %
491 %
T2-FLAIR
CSF tracer efflux to parasagittal dura
Ringstad and Eide (Nat Comm, 2020)
Kutomi O and Takeda S Microscopy, 2020
Endothelial lined gaps exist in parasagittal dura:
Da Mesquita et al. (Neuron, 2018)
CSF connects brain glymphatics with the immune system
Ringstad and Eide (Nat Comm, 2020) Rustenhoven and Kipnis (Science, 2019)
24 timer post IT 48 timer post IT
Images: Tomas Sakinis, MD
48 timer post IT
Ringstad and Eide (Nat Comm, 2020)
CSF tracer accumulates around parasagittal dura at late time points
In submission, Jan 2021 Jacob et al., Nat Comms 2019
EEvidence of significant spinal CSF clearance
Conclusions:
• The complexity of CSF dynamics is high, our understanding is incomplete
• CSF within the SAS is continuous with all brain regions • Healthy arteries and sleep are important for normal function of the glymphatic system • The glymphatic system and meningeal lymphatics add a metabolic and immunological dimension to CSF flow
MRI markers of CSF tracer dynamics in iNPH
Eide et al. (Brain Comms, 2020)
Future prospect : Extra-vascular CE MRI?
Cuddapah et al. (Nat Reviews Neuroscience, 2014)
?
Kilsdonk et al. (Brain, 2016)
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Glioma
MS
T2 gMRI
gMRI DIR
Future prospects: Pre-clinical AD diagnosis? Suggested reading: • Nedergaard M and Goldman SA. Glymphatic failure as a final common pathway to dementia (Science, 2020) • Da Mesquita S, Fu Z, Kipnis J. The meningeal lymphatic system: A new player in neurophysiology (Neuron, 2018) • Rustenhoven J and Kipnis J. Bypassing the blood-brain-barrier (Science, 2019)
• Pizzo ME, Wolak DJ, Kumar NN et al. Intrathecal antibody distribution in the rat brain: surface diffusion, perivascular transport and osmotic enhancement of delivery (J Physiol, 2018) • Wardlaw JM, Benveniste H, Nedergaard M et al. Perivascular spaces in the brain: anatomy, physiology and pathology (Nature reviews, 2020)