James Thomas¹, Peter Jezzard¹, and Alastair Webb^1
1University of Oxford, Oxford, United Kingdom

We tested whether clinically-relevant, vascular-origin low frequency oscillations (LFOs) in 0.05–0.15 Hz could be derived on routinely-acquired resting-state BOLD-fMRI to determine their potential as a marker of vascular dysfunction in cerebral small vessel disease. Our case control study in 840 UK Biobank participants showed a statistically significant increase in LFOs in the arterial vessels of participants with high white matter hyperintensities, consistent with greater transmission of arterial blood pressure to the cerebral circulation in subjects with increased arterial stiffness. LFOs could provide a practical measure, applicable to large datasets and clinical practice, as an index of intracerebral vascular dysfunction.

Angela CC Jochems^1,2, Susana Muñoz Maniega¹, Una Clancy^1,2, Daniela Jaime Garcia^1,2, Stewart Wiseman^1,2, Gordon W Blair¹, Rosalind Brown^1,2, Ellen V Backhouse^1,2, Carmen Arteaga^1,2, Will Hewins^1,2, Eleni Sakka^1,2, Agniete Kampaite^1,2, Michael S Stringer^1,2, Michael J Thrippleton^1,2, Mark E Bastin¹, Maria Valdés Hernández^1,2, Ian Marshall¹, Fergus N Doubal^1,2, and Joanna M Wardlaw^1,2
1Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom, ²UK Dementia Research Institute, University of Edinburgh, Edinburgh, United Kingdom

White matter hyperintensities (WMH) have been shown to progress over time but they might regress too. Little is known about the regression of WMH as the main focus has been on progression. We investigate WMH regression and their dynamic properties using diffusion MRI. Areas of WMH change, both progression and regression, might have different tissue integrity properties than areas that are more stable, i.e. stable normal-appearing white matter (NAWM), become more hyperintense, or stable WMH. Mean diffusivity and peak width of skeletonized mean diffusivity (PSMD) might be most sensitive to subtle integrity changes before they become visible on structural MRI.

Jacqueline Chen¹, Ajay Nemani¹, Xuemei Huang¹, Xin Li¹, Kyle O'Laughlin¹, Ela Plow¹, Kenneth B Baker¹, Mark J Lowe¹, Stephen E Jones¹, and Andre G Machado^1
1Cleveland Clinic, Cleveland, OH, United States

Prior to the implantation of brain stimulating electrodes, it would be valuable to have an estimation of the severity of pre-existing injury to the pathways of interest. In chronic stroke patients, we used resting-state functional MRI and transcranial magnetic stimulation (TMS) to identify functionally connected regions of the dentatothalamocortical pathway. We found that diffusion tensor imaging metrics of the tract connecting thalamus to the hand-motor hotspot were significantly correlated with hand function. These results suggest that this non-invasive functional/structural MRI/TMS approach can provide pathway-specific injury metrics that may be useful as part of a pre-surgical evaluation.

Wesley Thomas Richerson¹, Brian Schmit¹, and Dawn Wolfgram^2
1Biomedical Engineering, Marquette Medical College of Wisconsin, Milwaukee, WI, United States, ²Department of Medicine, Medical College of Wisconsin, Wauwatosa, WI, United States

We collected brain MRI data using a custom, advanced diffusion sequence as well as typical T1 and T2 FLAIR anatomical images to characterize the differences between controls and Hemodialysis (HD) patients in a pilot study. We found decreased gray matter volume and thickness as well as increased white matter hyperintensity lesion volume in HD patients. Using the Mean Apparent Propagator technique, we found increased gray and white matter mean square displacement, white matter q space inverse variance and return to plane probability.

Gawon Lee¹, Ji Wan Son¹, Ken SaKaie², Woojin Jung³, and Se-hong Oh^1,2
1Division of Biomedical engineering, Hankuk University of Foreign Studies, Yongin-si, Gyeonggi-do, Korea, Republic of, ²Imaging institute, Cleveland Clinic Foundation, Cleveland, OH, United States, ³AIRS Medical, Seoul, Korea, Republic of

Even subtle differences in masks can generate systematic but avoidable errors in QSM calculations. We believe these errors propagate through the calculation of the background phase. In this work, we assessed the effect of the mask on the QSM, selected optimal mask generation method and Deep Learning-based efficient mask generation method for in-vivo has been presented. This study represents the first step towards a fully-automated and optimal workflow for QSM calculation.

Russell Murdoch¹, Hanne Stotesbury², Jamie Kawadler², Dawn Saunders², Fenella Kirkham², and Karin Shmueli^1
1Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom, ²Imaging and Biophysics, Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, United Kingdom

To investigate the composition of silent cerebral infarcts (SCI) in sickle cell anaemia (SCA), we compared the magnetic susceptibility (χ) and transverse relaxation rates (R2*) of segmented SCI lesions to normal appearing white matter (NAWM) in the contralateral hemisphere. In 37 SCA subjects and 8 healthy controls (HC), SCI lesions were significantly less diamagnetic and had significantly lower R2* relative to NAWM. The χ and R2* changes indicate demyelination within the lesions. R2* mapping suggests that SCI lesions are more demyelinated in the SCA subjects, relative to HC, likely due to the haemodynamic challenges associated with the condition. 

Jian Shen¹, Silvie Suriany², Clio Gonzalez-Zaccarias³, Botian Xu¹, Ashok Panigraphy⁴, Jon Detterich², and John C Wood^5
1Bioengineering, University of Southern California, Los Angeles, CA, United States, ²Children's Hospital of Los Angeles-USC KSOM, Los Angeles, CA, United States, ³Neurosciences, University of Southern California, Los Angeles, CA, United States, ⁴Radiology, Children's Hospital Pittsburgh, Pittsburgh, PA, United States, ⁵Pediatrics, Children's Hospital of Los Angeles-USC KSOM, Los Angeles, CA, United States

Surgical palliation of single ventricular heart disease (Fontan procedure) leads to poor cardiac output, high central venous pressures, and long-term multiorgan morbidity. We report cerebral blood flow, brain oxygen delivery, and cerebral metabolic rate in 20 Fontan survivors  and 9 control subjects. Fontan patients had lower cerebral blood flow and oxygen saturation but maintained cerebral oxygen delivery and cerebral metabolic rate of oxygen (CMRO₂) because of polycythemia. Scattergram between CMRO₂ and O₂ delivery suggests similar oxygen extraction at the microvascular level in both groups. Taken together, these data suggest adequate cerebrovascular compensation to low cardiac output in Fontan patients.

Ashu Bhasin¹, Pawan Kumar², S Senthil Kumaran², Sujeet Mewar², and MV Padma Srivastava^1
1Department of Neurology, All India Institute of Medical Sciences, New Delhi, India, ²Department of NMR and MRI Facility, All India Institute of Medical Sciences, New Delhi, India

High resolution NMR spectroscopy to study the neural and cellular metabolites from serum samples of 14 chronic stroke patients after autologous bone marrow derived mononuclear stem cells and neurorehabilitation using 700 MHz NMR spectrometer. The data were processed using the Agilent software, Vnmrj2.3A. PLS-DA multivariate analysis was performed to explore biochemical shifts and upregulation between patients with stem cell infusion and controls. Using MetaboAnalyst (3.0) software, we observed elevated levels of myoinositol, choline, NAA, ML in one group 1 as compared to group 2 (groups undisclosed).

Shiyun Zhang¹, Kunhua Wu², Guoli Bi², Shaoyu Wang³, Yunzhu Wu³, Guoqing Xie⁴, and Qian Wang^4
1Dali university, Dali, China, ²The First People's Hospital of Yunnan Province, Kunming, China, ³MR Scientific Marketing, Siemens Healthineers, Shanghai, China, ⁴Kunming University of Science and Technology, Kunming, China

Hypertension is becoming a common health problem all over the world. In this study, Quantitative Susceptibility Mapping (QSM) was used to compare the differences of iron deposition in deep brain nuclei between 28 primary grade 1 hypertension (PG1H) patients and 28 age-sex-matched healthy controls (HC). The results showed that the iron deposition in six deep brain nuclei ROIs were higher in PG1H than in HC. This study laid a foundation for exploring the relationship between the hypertension severity and iron deposition in deep brain nuclei. It was also of great significance for clinical exploration of the physiological and pathological mechanism of hypertension and the correct selection of the treatment scheme of hypertension.