Grant S Roberts¹, Anthony Peret², Leonardo Rivera-Rivera^1,3, Karly A Cody³, Howard A Rowley², Oliver Wieben^1,2, Sterling C Johnson³, Kevin M Johnson^1,2, and Laura B Eisenmenger^2
1Dept of Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, ²Dept of Radiology, University of Wisconsin - Madison, Madison, WI, United States, ³Dept of Medicine, University of Wisconsin - Madison, Madison, WI, United States

It has been shown that vascular disease is strongly associated with Alzheimer’s disease (AD). It is thus important to establish normative cerebrovascular hemodynamics in aging populations. In this study, we comprehensively assess macrovascular hemodynamics using 4D flow MRI to obtain flow rates and pulsatility indices in 110 cognitively healthy, older adults and correlate these measures with age, sex, atherosclerotic cardiovascular disease (ASCVD) risk scores, and APOE genotypes. We found a (1) negative correlation between flow vs. age and flow vs. ASCVD, (2) a positive correlation between pulsatility vs. age and pulsatility vs. ASCVD, and (3) no correlations with APOE genotypes.

Rick J. van Tuijl¹, Ynte M. Ruigrok², Kimberley M. Timmins¹, Birgitta K Velthuis¹, Pim van Ooij¹, Jaco J.M. Zwanenburg¹, and Irene C. van der Schaaf^1
1Radiology, UMC Utrecht, Utrecht, Netherlands, ²Neurology, UMC Utrecht, Utrecht, Netherlands

The influence of maximum wall shear stress (WSS_MAX) and velocity pulsatility (vPI) are extensively investigated in aortic aneurysms, but its influence along the Circle of Willis (CoW) in patients with unruptured intracranial aneurysms (UIA) is unknown. Thirteen patients with an UIA were scanned at 7T-MRI using 4D phase-contrast MRI, comparing hemodynamic parameters between the parent artery of the UIA and the corresponding contralateral artery. The parent vessel of the UIA showed significantly higher WSS_MAX, blood-flow and velocity, and lower vPI compared to the unaffected contralateral side. This study supports a hemodynamic role in the aetiology of aneurysm formation.

Camila Munoz¹, Anastasia Fotaki¹, Reza Hajhosseiny¹, Karl P Kunze², Radhouene Neji^1,2, René M Botnar¹, and Claudia Prieto^1
1School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, ²MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom

Bright- and black-blood imaging are key contrasts for the assessment of lumen and vessel wall integrity in aortic MRI. These contrasts are usually acquired separately, resulting in long and inefficient examinations. Here we extend a previously introduced motion-compensated interleaved acquisition (iT2Prep-BOOST) to produce high-quality co-registered 3D bright- and black-blood images from a short predictable scan of ~8min. The proposed iT2Prep-BOOST approach resulted in bright-blood images with improved contrast compared to conventional bSFFP images, and black-blood images with increased volumetric coverage and resolution compared to conventional HASTE images, showing promise for a comprehensive assessment of aortic disease from a single scan.

Jae W. Song¹, Jiayu Xiao², Steven Y Cen², Xiao Liu³, Fang Wu⁴, Konrad Schlick⁵, Qi Yang³, Shlee S Song⁵, and Zhaoyang Fan^2
1University of Pennsylvania, Philadelphia, PA, United States, ²University of Southern California, Los Angeles, CA, United States, ³Chaoyang Hospital, Beijing, China, ⁴Xuanwu Hospital, Beijing, China, ⁵Cedars-Sinai Medical Center, Los Angeles, CA, United States

Hypertension is associated with intracranial atherosclerosis (ICAS) and is a leading cause of acute ischemic stroke (AIS). Given sex-differences in the severity of hypertension, we hypothesized sex-differences in ICAS burden among hypertensive patients with AIS. Results show males have significantly higher adjusted total plaque burdens than females. Subgroup analyses show treated hypertensive males with AIS have higher total proximal and bifurcation plaques than treated females. Untreated hypertensive females have significantly higher total proximal and bifurcation plaques compared to untreated males. The results suggest attention to differential hypertension management by sex may be warranted to reduce ICAS burden and AIS risk.

Karolina Wartolowska¹ and Alastair JS Webb^1
1University of Oxford, Oxford, United Kingdom

Small vessel disease is a common cause of white matter damage in older people. It is strongly associated with age, hypertension, diabetes, and obesity. We have investigated the associations between body mass index (BMI) and diffusion changes (adjusted for other risk factors) in data from UK Biobank. BMI was more strongly related to diffusion changes in inferior brain regions, depending on whether the white matter tracts were within the anterior or posterior circulation. Obesity affects white matter integrity, beyond the effect of cardiovascular risk factors.

Chun-Xia Li¹, Frank Tong², Doty Kempf¹, Leonard Howell¹, and Xiaodong Zhang^1
1Emory University, Atlanta, GA, United States, ²Department of Radiology, Emory University, Atlanta, GA, United States

Somatosensory deficits are seen in most stroke patients and can improve during recovery from stroke as reported previously. However, the underlining mechanism of the recovery remains poorly understood. The nonhuman primate (NHP) model of stroke has demonstrated similar functional connectivity evolution as seen in stroke patients and the secondary somatosensory cortex (S2) in NHPs is recognized as a direct extrapolation of somatosensory cortex in human. In the present study, the progressive function alteration of S2 and its relationship with the cerebral blood flow (CBF) and T2 changes in the monkey brain during acute stroke were examined and evaluated.

Wouter Schellekens¹, Alex Bhogal¹, Emiel Roefs¹, Mario Báez-Yáñez¹, Jeroen Siero¹, and Natalia Petridou^1
1UMC Utrecht, Utrecht, Netherlands

In the current study, we quantify vascular properties in relation to laminar BOLD fMRI signals for differently sized vascular compartments across cortical depth. Using hypercapnic and hyperoxic breathing conditions, while measuring from macro- and micro-vascular compartments, we estimate effects of dilation capacity, theoretical maximum signal intensity, and relative change in cerebral blood volume on laminar BOLD contrasts. We show that enlarged signals for larger pial veins are mainly caused by their capacity for dilation. BOLD signal differences between macro- and micro-vascular compartments are not likely caused by differences in theoretical maximum signal intensity, or relative changes in cerebral blood volume.