Stanley D.T. Pham¹, Hilde van den Brink², Tine Arts¹, Jeroen C.W. Siero¹, Jeroen Hendrikse¹, Jaco J.M. Zwanenburg¹, and Geert Jan Biessels^2
1Radiology, UMC Utrecht, Utrecht, Netherlands, ²Neurology and Neurosurgery, UMC Utrecht, Utrecht, Netherlands

We assessed blood-flow velocity measurements on 7T MRI as a potential disease marker for cerebral small vessel disease (SVD). Two-dimensional phase-contrast velocity measurements were performed in perforating arteries of the basal ganglia (BG) and white matter of the centrum semiovale (CSO) in patients with sporadic SVD and age- and sex-matched controls. Pulsatility index (PI) was significantly higher in the BG, in patients (0.45 [0.41–0.49] vs. 0.36 [0.30–0.41] in controls) (p=0.02). In the CSO, similar number of vessels, mean velocity, and PI were observed between patients and controls. BG pulsatility could be a potential marker for SVD.

Curtis Gregory Triebswetter (Co-Author)¹, Matthew Kiely (Co-Author)¹, Zhaoyuan Gong¹, Maryam H. Alsameen¹, and Mustapha Bouhrara^1
1National Institute on Aging, Baltimore, MD, United States

Maintenance of cerebral tissue homeostasis is particularly sensitive to deficits in cerebral blood flow (CBF) and concomitant hypoxia and hypoglycemia. However, little work has been conducted to investigate the potential association between deficits in CBF and deterioration of brain microstructure, especially in normative aging. The results of our analysis, conducted on a large cohort of cognitively unimpaired adults, of the association between CBF and several MRI metrics of cerebral microstructural integrity, indicate that low CBF values correspond to low tissue integrity. These results provide further evidence of the intimate relationship between neurovascular physiology and brain integrity throughout normative aging.

Spencer L Waddle¹, Maria E Garza¹, Larry Taylor Davis², Rohan Chitale^2,3, Matthew Fusco^2,3, Chelsea A Lee⁴, Niral J Patel⁴, Lori C Jordan^1,2,4, and Manus J Donahue^1,5
1Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States, ²Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, ³Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, TN, United States, ⁴Department of Pediatrics, Division of Pediatric Neurology, Vanderbilt University Medical Center, Nashville, TN, United States, ⁵Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, United States

The goal of this work is to apply time-regression analysis to hypercapnic reactivity data in an interventional trial to identify pre-surgical indicators of treatment response in moyamoya vasculopathy patients. We hypothesized that pre-surgical posterior flow-territory reactivity, including greater cerebrovascular reactivity and reduced vascular delay time, portend collateralization success. In 41 participants evaluated pre and 1-year post-operatively, pre-surgical posterior flow-territory maximum reactivity was higher (p=0.02) in patients with good vs. poor angiographic outcomes. This highlights that topographical features of preserved cerebral auto-regulation may contribute to neoangiogenic potential, and importantly, that reactivity mapping may provide a diagnostic tool for informing surgical candicacy.

David Marlevi^1,2, Edward Ferdian³, Jonas Schollenberger⁴, Maria Aristova⁵, Brandon Hardy⁴, Elazer R Edelman¹, Susanne Schnell^5,6, C. Alberto Figueroa⁴, David A Nordsletten^4,7, and Alistair A Young^3,7
1Massachusetts Institute of Technology, Cambridge, MA, United States, ²Karolinska Institutet, Stockholm, Sweden, ³University of Auckland, Auckland, New Zealand, ⁴University of Michigan, Ann Arbor, MI, United States, ⁵Northwestern University, Chicago, IL, United States, ⁶University of Greifswald, Greifswald, Germany, ⁷King's College London, London, United Kingdom

Changes in regional hemodynamics are indicative of cerebrovascular disease. However, image-based monitoring is complicated by the unique flow and anatomies found in the brain, with accurate estimates requiring beyond state-of-the-art image resolutions. To address this, we combine a deep residual network, 4D Flow MRI, and physics-informed image processing to provide super-resolution flow images and coupled accurate quantification of intracranial relative pressure. The method is trained and validated on patient-specific in-silico data, highlighting how low resolution-biases are mitigated by super-resolution conversion. Data were also effectively generated at <0.5 mm in a representative in-vivo cohort, highlighting the potential of our presented approach. 

Alex A Bhogal^1
1UMC Utrecht, Utrecht, Netherlands

Brain stress testing using blood oxygenation level-dependent (BOLD) MRI to evaluate changes in cerebrovascular reactivity (CVR) is of growing interest for evaluating white matter integrity. However, even under healthy conditions, the white matter BOLD-CVR response differs notably from that observed in the gray matter. The confluence of arterial hemodynamics and BOLD signal characteristics weighted by venous architecture unrelated to smooth-muscle mediated dilation/contraction play a significant role in defining the WM BOLD-signal response to hypercapnia. This caveat should be taken into account when attributing disease mechanisms and/or progression to presumed impaired WM BOLD-CVR.