Leonie Petitclerc^1,2, Lydiane Hirschler¹, Jack A. Wells³, David L. Thomas^4,5,6, and Matthias J.P. van Osch^1,2
1C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, ²Leiden Institute for Brain and Cognition (LIBC), Leiden, Netherlands, ³UCL Centre for Advanced Biomedical Imaging, Division of Medicine, University College London, London, United Kingdom, ⁴Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom, ⁵Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom, ⁶Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom

In order to measure the function of the blood-CSF barrier (BCSFB), a modified ASL experiment is introduced. This is accomplished with multiple time-points, including long labeling duration and post-labeling delay, and an echo train of 8 TEs from 10-1837ms. Long-T2 ASL signal, attributable to the CSF, was found both in the choroid plexus and around the cortex. Fitting of this signal to two models (a simple triexponential and a dynamic compartmental model) reveals an amount of CSF signal about 5 times lower than the perfusion. The transfer time of water across the BCSFB is estimated at around 100s.

Maria Marcella Lagana¹, Noam Alperin², Laura Pelizzari¹, Ning Jin³, Domenico Zaca⁴, Marta Cazzoli¹, Giuseppe Baselli⁵, and Francesca Baglio^1
1CADiTeR, IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy, ²University of Miami, Miami, FL, United States, ³MR R&D Collaborations, Siemens Medical Solutions USA, Inc., Cleveland, OH, United States, ⁴Siemens Healthcare, Milan, Italy, ⁵Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy

We used real-time phase contrast MRI for assessing the cardiac and respiratory influence on the neck arterial and venous flows, and on the cervical cerebrospinal fluid (CSF) flow. Changes due to the type of breathing were investigated acquiring six healthy volunteers for 60s during normal and deep breathing. The power spectra were computed from the flow rates. Two main peaks, corresponding to the breathing rate (BR) and the heart rate (HR), were found. Comparing deep breathing to normal breathing, we observed the following trends: decrement of average blood flow rates; reversal of average CSF flow rate; increment of BR power.

Nivedita Agarwal¹, Olivier Baledent², Giuseppe Nicolò Frau³, and Sabino Walter Della Sala^1
1Radiology, APSS Ospedale Santa Maria del Carmine, Rovereto, Italy, ²University of Amiens, Amiens, France, ³Otorhinolaryngology, APSS Ospedale Santa Maria del Carmine, Rovereto, Italy

Meniere’s disease patients have a high incidence of abnormal neck venous vessels. An inefficient intracranial venous outflow would disturb global neurofluids dynamics and alter intracranial pressure. We used phase contrast MRI to correlate the dynamics of total arterial, total venous and CSF with morphological alterations in internal jugular veins (IJV). Our results show that although >80% of  patients have IJV stenosis and isolated CSF and/or blood flow  abnormalities, the global neurofluid dynamics remained unhampered. These results underscore the optimal compensation provided by collateral venous pathways and suggests that PC-MRI is an important adjunct clinical tool to to study neurofluids dynamics.  

Stephanie D Williams¹, Nina E Fultz², Nicole Tacugue³, Zenia Valdiviezo³, and Laura D Lewis^2
1Psychological and Brain Sciences, Boston University, Boston, MA, United States, ²Biomedical Engineering, Boston University, Boston, MA, United States, ³Boston University, Boston, MA, United States

Cerebrospinal fluid (CSF) flow is essential for brain health, and previous studies have shown that it is driven by systemic physiological factors, such as breathing. Recent work has shown that neural activity is coupled to CSF flow during sleep, but whether this relationship reflects a causal link has not been tested. Here we investigated whether driving neural activity can induce changes in CSF flow. We found that we could induce CSF flow in the human brain during the awake state by manipulating hemodynamics with stimulus-evoked neural activity.

Marco Muccio¹, David Chu², Lawrence Minkoff², Neeraj Kukarni², Brianna Damadian², Raymond Damadian², and Yulin Ge^1
1Department of Radiology, New York University Grossman School of Medicine, New York City, NY, United States, ²FONAR Corporation, Melville, NY, United States

CSF exchange between the spinal cord and the cranium increases in asymptomatic human subjects when body position is shifted from upright to supine. This appears to be caused by an increase in CSF flow during diastole, in the caudo-cranial direction, and systole, in cranio-caudal direction. Extrapolation of the results showed that within a 24 hour timescale, the more time spent in the supine position (asleep) correlated with more CSF exchanged between the spinal cord and the intracranial space. These alterations can therefore play a major role in brain waste clearance, and possibly many neurodegenerative diseases as well as age-related ailments.

Di Cao^1,2, Ningdong Kang¹, Jay J. Pillai¹, Xinyuan Miao^1,2, Adrian Paez², Xiang Xu^1,2, Jiadi Xu^1,2, Xu Li^1,2, Qin Qin^1,2, Peter C.M. Van Zijl^1,2, Peter Barker¹, and Jun Hua^1,2
1Johns Hopkins University, Baltimore, MD, United States, ²Kennedy Krieger Institute, Baltimore, MD, United States

The circulation of cerebrospinal fluid (CSF) influences various aspects of brain physiology. This study aims to develop and optimize MRI sequences that can detect dynamic signal changes in the CSF after Gd administration with a sub-millimeter spatial resolution, temporal resolution of <10s, and whole brain coverage. Bloch simulations were performed to determine optimal imaging parameters. Simulations were validated with phantom scans. An optimized turbo-spin-echo (TSE) sequence was performed on healthy volunteers on 3T and 7T.  In human scans, dynamic signal changes after Gd injection in the CSF were detected at location where cerebral lymphatic vessels were identified in previous studies.

M. van den Kerkhof^1,2, M.M. van der Thiel^1,2, I.H.G.B. Ramakers^2,3, R.J. van Oostenbrugge^2,4,5, A.A. Postma¹, A.A. Kroon^5,6, J.F.A. Jansen^1,2,7, and W.H. Backes^1,2,5
1Department of Radiology & Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands, ²School for Mental Health & Neuroscience, Maastricht University, Maastricht, Netherlands, ³Department of Psychiatry & Neuropsychology, Maastricht University, Maastricht, Netherlands, ⁴Department of Neurology, Maastricht University Medical Center, Maastricht, Netherlands, ⁵School for Cardiovascular Disease, Maastricht University, Maastricht, Netherlands, ⁶Department of Internal Medicine, Maastricht University Medical Center, Maastricht, Netherlands, ⁷Department of Electrical Engineering, Eindhoven University of Technology, Maastricht, Netherlands

Intracranial vessel wall alterations may lead to an increased blood flow pulsatility and the enlargement of perivascular spaces (ePVS). To examine the relationship between these measures, this 7T MRI study applied phase contrast MRI to measure blood flow velocity in the middle cerebral artery and lenticulostriate arteries (LSAs) and obtained ePVS visual rating scores. An increased LSA pulsatility index was found to be related to a higher number of ePVS in the basal ganglia and centrum semiovale. These findings are in support of underlying alterations of the cerebral small vessel wall, which influence both the ePVS and the pulsatility.

Muneeb A Faiq¹, Vishnu Adi¹, Anoop Sainulabdeen¹, Sophia Khoja¹, Carlos Parra¹, Giles Hamilton-Fletcher¹, Choong H Lee², Jiangyang Zhang², Gadi Wollstein¹, Joel S Schuman¹, and Kevin C Chan^1,2
1Department of Ophthalmology, New York University Grossman School of Medicine, New York, NY, United States, ²Department of Radiology, New York University Grossman School of Medicine, New York, NY, United States

To date, it remains unclear if a functional glymphatic system exists in the optic nerve (ON), partly because of limited in vivo methods for characterizing the cerebrospinal fluid (CSF) dynamics in the deeper brain regions. Here, we measured the spatiotemporal profiles in the ON using contrast-enhanced MRI after intrathecal gadolinium infusion, and observed indications for the existence of a molecular size-dependent and aquaporin-4 (AQP4) modulated glymphatic-like system in the ON. These findings may provide imperative insights into the waste clearance mechanisms of the visual system in health and disease.

Stefan E. Poirier^1,2, Neville Suskin³, Keith S. St. Lawrence^1,2, J. Kevin Shoemaker⁴, and Udunna C. Anazodo^1,2,5,6
1Lawson Imaging, Lawson Health Research Institute, London, ON, Canada, ²Medical Biophysics, Western University, London, ON, Canada, ³Cardiology, Western University, London, ON, Canada, ⁴School of Kinesiology, Western University, London, ON, Canada, ⁵Clinical Neurological Sciences, Western University, London, ON, Canada, ⁶Research Centre for Studies in Aging, McGill University, Montreal, QC, Canada

White matter (WM) degeneration is associated with cognitive impairment in coronary artery disease (CAD). We used diffusion tensor imaging to assess WM integrity in brains of CAD patients before and after cardiac rehabilitation (CR) and in young and old healthy controls (HC). Widespread WM changes were observed between older and younger HC, while robust WM changes were observed in WM regions linked to cognition in CAD patients at baseline with improvements following CR. In CAD, disease manifestation and brain aging may contribute to changes in brain WM macrostructure with potential influence on cognition, and these may be quelled by CR.

Merel M. van der Thiel^1,2, Whitney M. Freeze^2,3,4, Joost de Jong^1,2, Inez H.G.B. Ramakers^2,4, Walter H. Backes^1,2,5, and Jacobus F.A. Jansen^1,2,6
1Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands, ²School for Mental Health & Neuroscience, Alzheimer Center Limburg, Maastricht, Netherlands, ³Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, ⁴Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands, ⁵School for Cardiovascular Disease, Maastricht University, Maastricht, Netherlands, ⁶Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands

The interstitial fluid fraction assessed with spectral analysis in intravoxel-incoherent motion MRI can be a potential, non-invasive method to identify tissue damage on a microscopic level and to investigate glymphatic alterations within different disease states. The current multi-dimensional approach has a long acquisition time, thereby lowering the feasibility of IVIM as a measurement of ISF in clinical practice. This study simultaneously investigates potential group differences in the ISF-fraction in Alzheimer’s disease, mild cognitive impairment, and controls, and explores the possibility to shorten acquisition time drastically by examining the contribution of individual primary directions.