MR Elastography and MRI Volumetry of the Aging Brain
Kaspar Josche Streitberger¹, Dagmar Krefting², Friedemann Paul³, Dieter Klatt¹, Sebastian Papazoglou¹, Sebastian Hirsch¹, Jürgen Braun², Ingolf Sack^1
1Institute of Radiology, Charité - University Medicine Berlin, Berlin, Germany; ²Institute of Medical Informatics, Charité - University Medicine Berlin, Berlin, Germany; ³Neurocure, Charité - University Medicine Berlin, Berlin, Germany

Physiological aging of the brain is accompanied by ubiquitous degeneration of neurons and oligodendrocytes. An alteration of the cellular matrix of an organ impacts its macroscopic viscoelastic properties, which are characterized by mechanical parameters such as stiffness and internal friction. To date Magnetic Resonance Elastography (MRE) is the only non-invasive technique for measuring the shear viscoelastic properties of living brain. This study compares the decrease of brain stiffness with years of age in normal volunteers observed by MRE with loss of brain volume found by MRI volumetry.

Structural Brain Changes Throughout Adulthood - not available
Antonio Giorgio^1,2, Luca Santelli³, Valentina Tomassini¹, Rose Bosnell¹, Stephen M. Smith¹, Nicola De Stefano², Heidi Johansen-Berg^1
1FMRIB Centre, University of Oxford, Oxford, United Kingdom; ²Neurology and Neurometabolic Unit, University of Siena, Siena, Italy; ³Department of Neuroscience, University of Padua Medical School, Padua, Italy

Normal ageing is associated with gradual deterioration of brain structures. However, there is mixed evidence over the precise time course and spatial distribution of change. We studied a group of 66 adults aged between 23 and 81 years using voxel-based morphometry (VBM)-style analysis and diffusion tensor imaging (DTI). We found widespread reductions in GM volume from middle age onwards but earlier reductions were detected in frontal cortex. WM decline was detected earlier (in young adulthood) and more sensitively using DTI-based measures of microstructure than using markers of WM volume derived from conventional T1-weighted imaging.

Voxel-Based Multiple Regression of Multimodal MRI: Applications to Physiological Aging
Andrea Cherubini¹, Patrice Péran¹, Carlo Caltagirone¹, Gianfranco Spalletta^1
1Santa Lucia Foundation, Rome, Italy

We explored for the first time with a voxel-based approach the simultaneous variation induced by physiological aging on four quantitative MR parameters sensitive to complementary tissue characteristics (VBM, T2* relaxometry, DTI). This allowed us to compare the performance of different predictors and to identify without a priori information the best biomarker of age-induced structural variation for each voxel. Our results showed that brain areas most affected by age are evenly distributed between white matter and grey matter. Moreover, the best quantitative predictors in most brain areas resulted to be iron deposition and microstructural damage rather than macroscopic atrophy of tissues.

White Matter Structural Correlates of Cognitive Performance in the Temporal Lobe Projections
Efrat Sasson¹, Glen M. Doniger², Ofer Pasternak³, Tal Gonen⁴, Yaniv Assaf^5
1Neurobiology department, Tel Aviv University, Tel Aviv, Israel; ²Department of Clinical Science, NeuroTrax Corporation, Newark, NJ, United States; ³Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States; ⁴Psychology department, Tel Aviv University, Tel Aviv , Israel; ⁵Neurobiology department, Tel Aviv University, Tel Aviv, Israel

In this study we used the inter-subject variability in different cognitive domains to relate cognitive performance and WM integrity in five temporal projections: the uncinate fasciculus, fornix, cingulum, inferior longitudinal fasciculus, and superior longitudinal fasciculus. Subjects were 51 healthy volunteers, 25-80 years, completed cognitive tests and were scanned using DTI and DTI tractography was performed. The fibers exhibiting substantial correlation with cognitive performance are known to play an important part in the corresponding functional domain. Using the methodology performed here, DTI tractography enables anatomical definition of region of interest for correlation analysis of any behavioral parameters with diffusion indices.

DTI, T2 Relaxation and Volumetry of the Human Brain Corpus Striatum Across the Lifespan
Khader M. Hasan¹, Indika S. Walimuni¹, Humaira Abid¹, Larry A. Kramer¹, Richard E. Frye², Jack M. Fletcher³, Linda Ewing-Cobbs^2
1Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX, United States; ²Pediatrics, UTHSC, Houston, TX, United States; ³Psychology, University of Houston, Houston, TX, United States

In this work, we report for the first time a comprehensive account of the macro and microstructure of these structures using a large cross-sectional healthy cohort across the healthy lifespan (N=281 males and females aged 6-68 years). We demonstrate using a  validated novel DTI and atlas-based tissue segmentation approach that the MRI microstructural correlates of volume decrease of these structures bilaterally, in both men and women are a T2 relaxation that follows a U curve that is commensurate with a fractional ansiotropy increases with age and a U curve mean diffusivity. A strong correlation between T2 and mean, radial and axial diffusivities is also noted.  The interplay between T2 relaxation and DTI metrics was also examined.

Longitudinal Age-Related Changes in Radial and Axial Diffusion Using Tract-Based Spatial Statistics
Thomas Richard Barrick¹, Rebecca Anne Charlton², Ai Wern Chung², Christopher Alan Clark³, Hugh Stephen Markus^2
1Centre for Clinical Neuroscience, Saint George's, University of London, London, United Kingdom; ²Centre for Clinical Neuroscience, Saint George's, University of London, United Kingdom; ³Institute of Child Health, University College London, United Kingdom

The aim of this study is to use tract based spatial statistics to investigate local age-related white matter structural change on a voxel-by-voxel basis over a 2-year period. 74 middle-aged and elderly individuals were scanned at both time-points and fractional anisotropy, axial and radial diffusivity were measured. Significant increases in average radial diffusivity and decreases in FA were found throughout the white matter in contrast to greater variability in change (both increase and decrease) of axial diffusivity. This study is the first to investigate longitudinal change in axial and radial diffusivity with age.

Assessment of Age-Related Microstructural Changes in the Thalamus by Diffusional Kurtosis Imaging
Maria Fatima Falangola^1,2, Caixia Hu¹, Vitria Adisetiyo¹, Ali Tabesh¹, Wende R. Gelb¹, Jens H. Jensen¹, Joseph A. Helpern^1,2
1Radiology, New York University Langone Medical Center, New York, NY, United States; ²Center for Advanced Brain Imaging, Nathan Kline Institute, Orangeburg, NY, United States

The thalamus is a major subcortical relay station that filters incoming primary sensory input and modulates processed cortical information through reciprocal cortico-thalamic connections. Therefore, it is a key region for fronto-temporal communication and is crucial for modulating emotion and cognition in humans. We applied Diffusional Kurtosis Imaging (DKI) to investigate the age-related non-Gaussian patterns of microstructure change in the thalamus. The data presented here suggest that non-Gaussian metrics, particularly MK and Kra are the most useful in detecting developmental changes in the thalamus.

Quantitative Mapping of the Age-Dependence of Cerebral Blood Flow Using Pulsed Arterial Spin Labeling - not available
J. Jean Chen¹, H. Diana Rosas, ¹², David H. Salat^1
1A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States; ²Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States

Accurate measurement of regional cerebral blood flow (CBF) changes in aging using conventional techniques is hampered by low repeatability and partial-volume effects. In this work, we examine the feasibility of pulsed arterial-spin labelling in obtaining quantitative CBF maps in healthy adults, evaluating the impact of potential partial-volume effects and the robustness of calibration techniques. We observed cortical CBF decrease with healthy aging, with heightened reduction co-localizing with regions previously reported to exhibit decline in metabolism. These findings were independent of the choice of CBF calibration technique, and partial-volume effects were found to bias CBF in areas of significant cortical thinning.

Age and Gender Variations in T₁ Measurements of White and Grey Matter Structures Within the Human Brain at 7 T
Peter Jonathan Wright^1,2, Olivier Mougin¹, Susan Pritchard¹, Eleanor Cox¹, Penny Gowland^1
1SPMMRC, University of Nottingham, Nottingham, United Kingdom; ²LMBRU, Leeds NHS, Leeds, West Yorkshire, United Kingdom

With the increasing life expectancy of humans in the developed world and neurological diseases such as Parkinson’s becoming ever more prominent, a growing interest has emerged examining normal changes in brain tissue in later life. 30 healthy subjects between 40-80 years were scanned at 7 T using an MPRAGE sequence to measure T₁ recovery values in ROI of the brain. Significant age variations were observed between grey matter, anterior and posterior white matter (p = 0.02) dominated by male subjects and splenium and genu of the corpus callosum (p < 0.02), dominated by female subjects.

Correlation of Change in Phase and R2* with Putative Iron Content in Deep Gray Matter of Healthy Adults
Manju Liu¹, Mark E. Haacke¹, Charbel A. Habib¹, Yanwei Miao², Yashwanth Katkuri^1
1Department of Radiology, Wayne State University, Detroit, MI, United States; ²Department of Radiology, The First Affiliated Hospital, Dalian, Liaoning, China

In this project we applied a two region analysis to avoid this problem and to study not only iron increases but the overall area of iron content as a function of age.