ISMRM 24th Annual Meeting & Exhibition • 07-13 May 2016 • Singapore

Scientific Session: Normal Brain: Measurement & Characterisation

Tuesday, May 10, 2016
Hall 606
10:00 - 12:00
Moderators: Jalal Andre, Christopher G Filippi

UK Biobank: Brain imaging protocols and first data release
Karla L Miller1, Neal K Bangerter2, Fidel Alfaro Almagro1, David L Thomas3, Essa Yacoub4, Junqian Xu5, Andreas J Bartsch1,6, Saad Jbabdi1, Stamatios N Sotiropoulos1, Mark Jenkinson1, Jesper Andersson1, Ludovica Griffanti1, Peter Weale7, Iulius Dragonu7, Steve Garratt8, Sarah Hudson8, Rory Collins8,9, Paul M Matthews10, and Stephen M Smith1
1FMRIB Centre, University of Oxford, Oxford, United Kingdom, 2Electrical and Computer Engineering, Brigham Young University, Provo, UT, United States, 3Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom, 4Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 5Icahn School of Medicine at Mount Sinai, New York, NY, United States, 6Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany, 7Siemens Healthcare (UK), London, United Kingdom, 8UK Biobank Ltd, Stockport, United Kingdom, 9Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom, 10Department of Medicine, Imperial College London, London, United Kingdom
UK Biobank is a prospective epidemiological study of 500,000 participants consisting of extensive questionnaires, physical measures and biological samples, linking to long-term health outcomes. The imaging extension for the UK Biobank ultimately aims to image 100,000 subjects from this cohort, including brain, cardiac and body MRI, bone scans and carotid ultrasound. We overview the brain imaging component, which includes structural, functional and diffusion MRI. The value of this open resource arises not only from multi-modal/multi-organ imaging, but also from the depth of other demographic, phenotypic and exposure data, and will increase over time as clinical outcomes are realized in the population.

On the Relationship between Cellular and Hemodynamic Properties of the Human Brain Cortex over Adult Lifespan
Yue Zhao1, Jie Wen2, Anne Cross3, and Dmitriy Yablonskiy2
1Chemistry, Washington University in St. Louis, St. Louis, MO, United States, 2Radiology, Washington University in St. Louis, St. Louis, MO, United States, 3Neurology, Washington University in St. Louis, St. Louis, MO, United States
Establishing baseline MRI biomarkers for normal brain aging is significant and valuable. In this study, we use previously developed approach to measure tissue-specific transverse relaxation rate constant (R2*t) and BOLD contributions to GRE signal, thus providing information on tissue cellular and hemodynamic properties. The VSF approach is applied for background gradient correction together with navigator echo to minimize artifacts from physiological fluctuations. Our results show age-related R2*t increases in most cortical regions and age-independent behavior of most hemodynamic parameters. We hypothesize that R2*t could serve as a biomarker of the cortical “cellular packing density”, which mostly reflects the neuronal density.

Venous metrics in a large cohort of healthy elderly individuals from susceptibility-weighted images and quantitative susceptibility maps
Phillip G. D. Ward1,2, Parnesh Raniga1, Nicholas J. Ferris1,3, David G. Barnes2,4, David L. Dowe2, Elsdon Storey5, Robyn L. Woods6, and Gary F. Egan1,7
1Monash Biomedical Imaging, Monash University, Clayton, Australia, 2Faculty of Information Technology, Monash University, Clayton, Australia, 3Monash Imaging, Monash Health, Clayton, Australia, 4Monash eResearch Centre, Monash University, Clayton, Australia, 5Department of Neurology, Monash University, Clayton, Australia, 6Department of Epidemiology & Preventative Medicine, Monash University, Melbourne, Australia, 7ARC Centre of Excellence for Integrative Brain Function, Melbourne, Australia
In this study we examine venous characteristics of elderly individuals in a large healthy population. Venograms were generated from susceptibility-weighted images and quantitative susceptibility maps using state-of-the-art automated venography. Venous density and oxygen extraction fraction were calculated in different brain regions. The pattern of metabolic demand (oxygen extraction fraction) is found to be consistent with rest and passive observation. Additionally, our results suggest that venous density may be a potential biomarker.

In Vivo Characterization of Brain Ultrashort-T2 Components
Tanguy Boucneau1,2, Shuyu Tang1,3, Misung Han1, Roland G Henry1,4, Duan Xu1,3, and Peder Eric Zufall Larson1,3
1Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA, United States, 2Physics, Ecole Normale Supérieure de Cachan, Cachan, France, 3UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, San Francisco, CA, United States, 4Neurology, University of California - San Francisco, San Francisco, CA, United States
It has recently been shown that myelin contains ultrashort T2 components with sub-millisecond relaxation times that are not observed with conventional pulse sequences and maybe associated with bound protons in the myelin phospholipid membranes.We performed ultrashort T2* relaxometry in vivo to characterize these components with a 3D ultrashort echo time (UTE) pulse sequence at 7T.We observed an ultrashort T2 component (T2* $$$\approx 100 \mu s$$$) as well as a short T2 component (T2* $$$\approx 1.5 ms$$$) that had a distinct frequency shift corresponding to the methylene proton chemical shift, which to our knowledge has never been observed in vivo.These components were validated in an ex vivo post-mortem brain specimen, and may provide valuable new biomarkers of myelin density, structure, and integrity.

Multi-parameter mapping, fat/water separation and functional imaging with a two-sequence brain morphometry protocol
Andre Jan Willem van der Kouwe1, Fikret Isik Karahanoglu1, Matthew Dylan Tisdall1, Paul Wighton1, Himanshu Bhat2, Thomas Benner3, and Jonathan R Polimeni1
1Athinoula A. Martinos Center, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 2Siemens Healthcare, Charlestown, MA, United States, 3Siemens Healthcare, Erlangen, Germany
We present an efficient two-sequence protocol for quantifying multiple parameters in a 1 mm isotropic brain morphometry examination. The protocol comprises a multiple gradient echo (TE), multiple inversion (TI) time MPRAGE (MEMPxRAGE) and a two-flip-angle balanced SSFP (TrueFISP) sequence. Proton density and T1 maps are estimated from the MEMPxRAGE data using the multi-TI data and a Bloch simulation. With the T1 map and TrueFISP data, the T2 map is estimated using DESPOT2. Fat, water and B0 maps are obtained from the multi-TE data using the IDEAL algorithm.  The MEMPxRAGE scan includes embedded 3D EPI-based navigators encoding low resolution functional information.

Reproducibility of fast three-dimensional macromolecular proton fraction mapping of the human brain: global tissue characterization and volume measurements
Vasily L. Yarnykh1,2
1Radiology, University of Washington, Seattle, WA, United States, 2Research Institute of Biology and Biophysics, Tomsk State University, Tomsk, Russian Federation
A new method for fast high-resolution whole-brain three-dimensional (3D) mapping of the macromolecular proton fraction (MPF) based on three source images has been recently proposed. In this study, reproducibility of repeated MPF measurements in white and gray matter with simultaneous estimation of tissue volumes using automated segmentation of 3D MPF maps obtained with isotropic resolution of 1.25 mm was assessed. MPF measurements in brain tissues are highly reproducible with coefficients of variation <1.5%. 3D MPF mapping provides “all-in-one” solution for simultaneous characterization of myelination and volumetric changes in brain tissues.

Automated Measurements of Brain Morphometry Derived from T1-weighted Magnetic Resonance Imaging Fluctuate from Morning to Afternoon - Permission Withheld
Aaron Trefler1, Neda Sadeghi2, Adam Thomas1, Carlo Pierpaoli2, Chris Baker1, and Cibu Thomas3
1National Institute of Mental Health, Bethesda, MD, United States, 2National Institute of Child Health and Human Development, Bethesda, MD, United States, 3Center for Neuroscience and Regenerative Medicine, Bethesda, MD, United States
Automated measures of brain morphometry derived from T1-weighted (T1W) images are typically used as proxy measures to investigate the relation between brain structure and behavior. However, the computation of T1W morphometric measures can be influenced by subject-related factors such as head motion1 and level of hydration2. Here, we provide a comprehensive assessment of the impact of time-of-day (TOD) on widely used measures of brain morphometry in healthy young adults. Our results show that the apparent volume of all major tissue compartments as well as measures of brain morphometry such as cortical thickness and gray matter density are significantly influenced by TOD. 

Optimized Inversion-Time Schedules For High-Resolution Multi-Inversion EPI Quantitative Measurements of T1 - Permission Withheld
Ouri Cohen1,2, Ville Renvall3, and Jonathan Polimeni1,2
1Athinoula A. Martinos Center, Charlestown, MA, United States, 2Radiology, Massachusetts General Hospital, Boston, MA, United States, 3Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
A novel optimized method for high-resolution quantitative EPI measurements of T1 is introduced and validated on a 3T clinical scanner in a phantom and a healthy volunteer. The method offers a 5-fold acceleration in scan time over previous techniques allowing fully quantitative 1.2 mm3 isotropic T1 maps in less than 30 seconds. 

Cerebral gray matter volume changes caused by exposure to hypobaric environment: a preliminary study
Dandan Zheng1, Wenjia Liu2, Li Zheng3, and Lin Ma2
1MR Research China, GE Healthcare, Beijing, China, People's Republic of, 2Radiology Department, Beijing Military General Hospital, Beijing, China, People's Republic of, 3Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China, People's Republic of
Acute mountain sickness is a series of pathologic reactions during rapid exposing to low pressure hypoxic high altitude environment, which is a widespread illness among un-acclimatized individuals in plateau. Human always stay in plain will display some common physiological and pathological changes of brain, such as change of cerebral blood flow, cerebral pressure and brain volume. The aim of the present study was to investigate whether there was different change of gray matter volume in some brain regions related to AMS development before, during and after exposing to the real high altitude environment.

Regional Brain Motion Varies with Subject Positioning: A Study Using Displacement Encoding with Stimulated Echoes (DENSE)
Xiaodong Zhong1, Zihan Ye2, Tucker Lancaster3, Deqiang Qiu3, Brian M. Dale4, Amit Saindane3, and John N. Oshinski2,3
1MR R&D Collaborations, Siemens Healthcare, Atlanta, GA, United States, 2Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, United States, 3Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, United States, 4MR R&D Collaborations, Siemens Healthcare, Cary, NC, United States
Displacement encoding with stimulated echoes (DENSE) with high motion sensitivity was used to investigate the influence of subject position (prone versus supine) on regional brain motion. Preliminary results in 9 volunteers demonstrated that there is a significant difference in displacement with a change in position. Displacements were significantly increased in the frontal lobe going from the prone to the supine position and significantly increased in the occipital lobe going from the supine to the prone position.

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