Xia Zhe¹, Yang Huang¹, Min Tang¹, Kai Ai², Xiaoyan Lei¹, and Xiaoling Zhang^1
1Department of MRI, Shaanxi Provincial People’s Hospital, Xi’an, Shaanxi, China, ²Philips Healthcare, Xi’an, China

Sebastian Constantin Schneider^1,2, Mario Eduardo Archila-Meléndez^1,2, Jens Göttler^1,2, Stephan Kaczmarz^1,2,3, Jan Kufer^1,2, Benedikt Zott^1,2, Josef Priller⁴, Michael Kallmayer⁵, Claus Zimmer¹, Christian Sorg^1,2, and Christine Preibisch^1,2,6
1School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Neuroradiology, Technical University of Munich, Munich, Germany, ²School of Medicine, Klinikum rechts der Isar, TUM Neuroimaging Center, Technical University of Munich, Munich, Germany, ³Philips GmbH Market DACH, Hamburg, Germany, ⁴School of Medicine, Klinikum rechts der Isar, Department of Psychiatry, Technical University of Munich, Munich, Germany, ⁵School of Medicine, Klinikum rechts der Isar, Department of Vascular and Endovascular Surgery, Technical University of Munich, Munich, Germany, ⁶School of Medicine, Klinikum rechts der Isar, Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Department of Neurology, Munich, Germany

 

Blood oxygenation level dependent functional connectivity (BOLD-FC) is commonly used as a proxy for neuronal connectivity. Therefore, aberrant BOLD-FC in brain disorders is typically interpreted as aberrant neuronal connectivity. However, beyond changes in neuronal connectivity, impairments in neurovascular coupling (NVC) may also impact on BOLD-FC. This study investigates how impaired local NVC, under conditions of preserved neural functioning, influences BOLD-FC in a sample of unilateral asymptomatic internal carotid artery stenosis patients and healthy age-matched controls. We show that timing aspects of local NVC, namely increased capillary transit time heterogeneity, reduces BOLD-FC, without changes in neuronal functioning.

Ece Su Sayin¹, James Duffin^1,2, Julien Poublanc³, David John Mikulis³, Joseph Arnold Fisher^1,2, and Olivia Sobczyk^2
1Department of Physiology, University of Toronto, Toronto, ON, Canada, ²Department of Anaesthesia and Pain Management, University Health Network, Toronto, ON, Canada, ³Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, ON, Canada

Dynamic susceptibility contrast perfusion measures using hypoxia-induced deoxyhemoglobin (dOHb) and BOLD-MRI-CO₂ CVR reveals that patients with steno-occlusive disease can have the degree of hymodynamic compromise classified into two severities by the differences in hemodynamic measures at rest and in response to stress.

Jeremy Lee Smith¹, Anna Trofimova¹, Vishwadeep Ahluwalia^2,3, Jose J. Casado Garrido⁴, Julia Hurtado⁵, Rachael Frank⁵, April Hodge⁵, Russell K. Gore^4,5, and Jason W. Allen^1,4,6
1Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States, ²Georgia State University, Atlanta, GA, United States, ³Center for Advanced Brain Imaging, Georgia Institute of Technology, Atlanta, GA, United States, ⁴Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States, ⁵Shepherd Center, Atlanta, GA, United States, ⁶Neurology, Emory University School of Medicine, Atlanta, GA, United States

Convergent clinical and neuroimaging evidence suggests that cognitive-affective and vestibular symptoms are interrelated: affective disorders not only co-occur with vestibular dysfunction but may also influence vestibular processing. However, the topology of the vestibular/cognitive/affective network (‘vestibular neuromatrix’) is not well-defined. The present study leveraged graph theory metrics to assess the functional and structural connectivity among 82 regions of interest in healthy controls and in patients with subacute post-concussive vestibular dysfunction. Patients exhibited deficiencies in connectivity among vestibular, pre- and orbitofrontal, and visual regions, as well as in the integration of visual and vestibular information, visuospatial attention, and monitoring of internal state.

Luca Pasquini^1,2, Mehrnaz Jenabi³, Kyung Peck⁴, and Andrei Holodny^1
1Radiology, Memorial Sloan Kettering Cancer Center, New York City, NY, United States, ²NESMOS, La Sapienza University, Rome, Italy, ³Radiology, Memorial Sloan Kettering Cancer Center, New York CIty, NY, United States, ⁴Medical Physics, Memorial Sloan Kettering Cancer Center, New York City, NY, United States

Brain tumors lead to modifications of brain networks known as functional reorganization or plasticity, which may be compensatory in nature and lead to valuable clinical applications. However, the determinants of plasticity are unclear. We evaluated functional networks of 30 low-grade (LGG) and 30 high-grade (HGG) left-hemispheric gliomas versus 20 healthy controls (HC) through rs-fMRI and graph-theory. We hypothesized that tumor grade and location impact brain connectivity. Our results show that both LGG and HGG develop ipsilateral and contralateral functional network changes. Additionally, tumor location is crucial: frontal and temporal tumors show bilateral modifications; parietal and insular tumors only local effects.

Manoj Kumar¹, Sachin Patalasingh¹, Chandrakanta Hiremath¹, Jitender Saini¹, K. John VijaySagar², BK Yamini³, and Rose Dawn Bhrath^1
1Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bengaluru, India, ²Child and Adolescent Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India, ³Speech Pathology and Audiology, National Institute of Mental Health and Neurosciences, Bangalore, India

Resting-state fMRI studies performed during natural sleep indicate that functional-connectivity in ASD-children begins to differentially mature from earliest periods of life and continues to have distinct patterns throughout early development. In current study, we have performed rs-fMRI in younger (12 to 36-months-of-age) cohorts of ASD, ASD-siblings, and typically developing children to look for functional-connectivity patterns. We observed significantly reduced functional-connectivity in language, social-cognition, and motor regions than controls and ASD-siblings. Interestingly, some of these regions are also considerably different when compared between ASD and ASD-siblings. Altered connectivity may use for targeted interventional therapy for better clinical outcomes in ASD-children.

Qianwen Wu^1,2, Huaying Cai³, Linhui Ni³, Guocan Han⁴, Zhiyong Zhao¹, and Dan Wu^1
1Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China, ²Department of Engineering, University of Oxford, Oxford, United Kingdom, ³Department of Neurology, Neuroscience Center,, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China, ⁴Department of Radiology, Neuroscience Center,, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China

This study aimed to explore the changes of functional network connectivity (FNC) in post-stroke dementia (PSD) using a dynamic FNC (dFNC) method. We collected resting-state fMRI data from16 PSD patients, 20 post-stroke non-dementia (PSND) patients and 19 normal controls, and identified 13 functional networks. We found PSD-specific decreases in the dFNC between default mode network and executive control network as well as visual network, which were not observed in static FNC analysis. Moreover, PSD showed a significant decrease in time-variance of global efficiency in whole brain compared with PSND. These changes were associated with the clinical assessments of patients.

Unal Sakoglu¹, Amaresh Mishra¹, Kaundinya S Gopinath², Bruce A Crosson², and Robert Haley^3
1Computer Engineering, University of Houston-Clear Lake, Houston, TX, United States, ²Emory University, Atlanta, GA, United States, ³University of Texas Southwestern Medical Canter at Dallas, Dallas, TX, United States

Around 200,000 veterans suffer from Gulf War Illness (GWI). GWI is characterized by multiple deficits in cognitive, emotion, somatosensory and pain domains. In this study we studied 23 GWI patients and 30 age-matched control veterans with resting-state fMRI in order to classify patients versus controls using dynamic functional connectivity among brain networks. Results show that different brain networks have discriminating power, pointing to widespread impairments in functional connectivity of visual, semantic, multi-sensory, and sensory-motor processing networks in GWI, consistent with multi-symptom nature of GWI.

Jia Yan Shi¹ and Hua Jun Chen^2
1Fujian Medical University Union Hospital, Fuzhou, China, ²Radiology, Fujian Medical University Union Hospital, Fuzhou, China

In this study, we made the first investigation on abnormal pattern of dynamic functional connection density (dFCD) in ALS. We gathered resting state functional magnetic resonance imaging (fMRI) data from 50 patients with ALS and 55 healthy controls (HC). dFCD was analyzed by sliding window correlation method; and the standard deviation of dFCD across the sliding window was calculated voxel-wisely to quantify dFCD variability. Our study has found abnormal dFCD variability in ALS. The indices of dFCD variability showed moderate discrimination power between two groups, suggesting its potential serving as the diagnostic biomarker for ALS.

LiMin Cai¹ and HuaJun Chen^1
1Fujian Medical University Union Hospital, Fuzhou, China

We explored dynamic functional network connectivity (dFNC) in ALS and its correlation with disease severity. FNC states were determined by k-mean clustering, and state-specific FNC and dynamic indices (fraction time/mean dwell time/transition number) were calculated. ALS patients showed increased FNC between DMN-SMN in state 1 and between CCN-SMN in state 4. Patients remained in state 2 (showing the weakest FNC) for a significantly longer time and remained in state 1 (showing a relatively strong FNC) for a shorter time. A significant correlation was observed between ALSFRS-R and mean dwell time in state 2 and transition number.

Joseph Schaefer¹, Jingya Miao², Caio Matias², Feroze Mohamed², Laura Krisa², James Harrop², and Mahdi Alizadeh^2
1Neurological Surgery, Thomas Jefferson University, Philadelphia, PA, United States, ²Thomas Jefferson University, Philadelphia, PA, United States

The purpose of this study is to investigate the distributed network properties of subjects with pediatric spinal cord injury using static and dynamic functional connectivity analysis. 36 subjects of which 18 had history of SCI between the ages of 0-18 years underwent 3-Tesla resting state functional MRI (rs-fMRI). Static and dynamic functional connectivity was calculated. Results showed patients with a history of pediatric spinal cord injury did not show widespread changes in static functional connectivity but did have significant changes in dynamic functional connectivity, including spending more time in a relatively hypoconnected brain state and less brain state transitions. 

Jia Yan Shi¹ and Hua Jun Chen^2
1Radiology, Fujian Medical University Union Hospital, Fuzhou, China, ²Fujian Medical University Union Hospital, Fuzhou, China

 Static and dynamic analyses for identifying functional connectivity(FC)have demonstrated brain dysfunctions in amyotrophic lateral sclerosis(ALS).We are to make the first attempt to perform studies about the stability of dynamic FC analysis based on resting-state fMRI data, in order to provide the new insight into the mechanism in ALS and investigate its correlation with disease severity. Our observation revealed that the abnormal pattern of FC stability involved sensorimotor regions(i.e.left precentral and postcentral gyrus)and non-sensorimotor areas(i.e.right temporal pole and middle/inferior frontal gyrus)in ALS patients, suggesting the potential of functional stability serving as the biomarker for monitoring disease progression in ALS.