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

Scientific Session: The Aging Brain

Monday, May 9, 2016
Hall 606
10:45 - 12:45
Moderators: Claudine Gauthier, Hanzhang LU

Reduced functional segregation between the default mode network and the executive control network in healthy older adults: a longitudinal study
Kwun Kei Ng1, June C. Lo1, Michael W.L. Chee1, and Juan Zhou1,2
1Duke-NUS Graduate Medical School, Singapore, Singapore, 2Clinical Imaging Research Centre, the Agency for Science, Technology and Research and National University of Singapore, Singapore, Singapore
The effects of age on functional connectivity (FC) of intrinsic connectivity networks (ICNs) have largely been derived from cross sectional studies. Far less is known about longitudinal changes in FC and how they relate to ageing-related cognitive decline. We found progressive loss of functional specialization with ageing evidenced by a decline in intra-network FC within the executive control (ECN) and default mode networks (DMN). In contrast, longitudinal change in FC between ECN and DMN followed a u-shaped trajectory whereby functional segregation between these two networks initially increased over time and later decreased as participants aged. The rate of loss in ECN-DMN functional segregation was associated with decline in processing speed.

Aging Effect on Creatine Kinase Enzyme Activity in Resting Human Brain: An In Vivo 31P-MT Study at 7T - Permission Withheld
Byeong-Yeul Lee1, Xiao-Hong Zhu1, and Wei Chen1
1Center for Magnetic Resonance Research, Radiology, University of Minnesota, Minneapolis, MN, United States
In this work, we investigated the aging effect on the enzyme activity of creatine kinase (CK) in healthy human visual cortex at resting state using a newly developed in vivo 31P magnetization transfer (31P-MT) method at 7T. Our results show that there was a strong aging dependence of the CK enzyme activity in the resting brain, implying a significant decline of brain energy metabolism in elderly people.  In vivo 31P-MT technique should provide a valuable tool for clinical research aiming to study aging-related neurodegenerative diseases such as Alzheimer’s disease, and potentially for other metabolic disorders/diseases. 

Cerebral venous oxygenation as a potential marker to differentiate normal aging from neurodegeneration
Zixuan Lin1, Marilyn Albert2, Peiying Liu3, Anja Soldan2, Abhay Moghekar3, Shin-Lei Peng4, Michael Miller1, Peter van Zijl3, and Hanzhang Lu3
1Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, 2Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 3Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4Department of Radiology, China Medical University, Taichung, Taiwan
Decreased cerebral venous oxygenation (Yv) has been considered as a compensation for aging which is diminished in neurodegeneration. We substantiated this hypothesis by examining the relationship between Yv and several Alzheimer-specific hallmarks on 65 normal elderly subjects. We demonstrated that Yv is higher in ApoE4 carriers who have increased risks of AD and that higher Yv is associated with poorer cognitive performance, indicating that assessment of Yv with non-invasive MRI methods may present a potential simple opportunity to identify the transition point from normal to pathological aging.

Hippocampal subfield diffusivity changes in healthy ageing
Daniel J Cox1,2, Hamied A Haroon2, Daniela Montaldi1, and Laura M Parkes2
1School of Psychological Sciences, University of Manchester, Manchester, United Kingdom, 2Centre for Imaging Sciences, University of Manchester, Manchester, United Kingdom
Alterations to hippocampal microstructure may precede gross volumetric changes in ageing, and these changes may occur preferentially in different hippocampal subfields. We investigated both established (FA and mADC) and novel (DOC) measurements of diffusion in these regions, in addition to volume, in order to determine where age-related changes occurred. The results showed changes across the majority of subfields for mADC and FA, but only in left CA 2/3 for DOC measures 1, 3 and >3. We suggest this could be related to differential degradation of particular cellular structures in these regions.

Early Shifts of Brain Metabolism by Caloric Restriction Preserve White Matter Integrity and Long-term Memory in Aging Mice
Janet Guo1, Ailing Lin1,2, and Vikas Bakshi1
1Department of Pharmacology & Nutritional Sciences, University of Kentucky, Lexington, KY, United States, 2Department of Biomedical Engineering, Lexington, KY, United States
Caloric restriction (CR) has been shown to increase healthspan in various species; however, its effects on preserving brain functions in aging remain largely unexplored. We used multimodal neuroimaging (PET/MRI/MRS) and behavioral testing to determine in vivo brain glucose metabolism, energy metabolites, and white matter structural integrity in young and old mice fed with either control or 40% CR diet. Blood glucose and ketone bodies were measured. Our findings suggest CR could slow brain aging, partly due to early shift of energy metabolism caused by lower caloric intake. These results provide rationale for CR-induced sustenance of brain health with extended longevity.  

Age-dependent changes in the BOLD Cerebrovascular Reactivity Curve in Response to Progressive Hypercapnia
Alex Bhogal1, Jill B de Vis1, Jeroen C.W. Siero1, Esben T Petersen2, Peter R. Luijten1, Jeroen Hendrikse1, Marielle E.P. Philippens3, and Hans Hoogduin4
1Radiology, UMC Utrecht, Utrecht, Netherlands, 2Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark, 3Radiotherapy, UMC Utrecht, Utrecht, Netherlands, 4Utrecht, Netherlands
Characterizing healthy, age-related changes in the BOLD-CVR response can provide a reference point from which to distinguish abnormal CVR from the otherwise normal effects of ageing. In this study, we examine age-dependent differences in grey and white matter BOLD-CVR response to progressive hypercapnia between young and elderly subjects. 

Assessment of cerebral response to exercise: effects of ageing and cardiorespiratory fitness
Andrew Hale1, Penny Gowland1, Paul Greenhaff2, and Susan Francis1
1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, 2Faculty of Medicine & Health Sciences, Queens Medical Centre, University of Nottingham, Nottingham, United Kingdom
Although there is a general relationship between age and brain function, habitual physical activity levels may also impact on brain health. We performed a MR study involving low and moderate intensity supine exercise in healthy young and older subjects. We assess the effect of exercise on CBF response in large arteries, regional perfusion and BOLD, and the relationship of grey matter volume with physical fitness and ageing. On exercise there was a clear CBF, perfusion and BOLD response to exercise in young volunteers, whilst a reduced CBF, perfusion and BOLD response to exercise was found in the older volunteers.

Consistent detection of age-dependent variations of the longitudinal relaxation time in cortical brain regions investigated by MP2RAGE at 9.4T: influence of correcting for a non-uniform transmit field
Gisela E Hagberg1,2, Jonas Bause1, Thomas Ethofer2,3, Philipp Ehses1, Thomas Dresler3, G Shajan1, Rolf Pohmann1, Cornelia Herbert3, Andreas Fallgatter3, Christoph Laske3, Marina Pavlova2, and Klaus Scheffler1,2
1High Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, 2Biomedical Magnetic Resonance, University Hospital Tübingen, Tübingen, Germany, 3General Psychiatry&Psychotherapy, University Hospital Tübingen, Tübingen, Germany
Accurate and precise determination of T1 values is of central importance in clinical studies and for tissue segmentation based on the myeloarchitecture that transcends T1. Here we investigate whether well-described age-dependent changes can be detected by high field T1 relaxometry, and how different transmit field correction methods influence the results. We found that the intrinsic bias correction of the MP2RAGE technique is not sufficient to achieve reliable quantification of T1 at ultra high magnetic fields. But, provided that a correction for transmit field inhomogeneity is performed, T1 maps that consistently reveal age-related changes can be generated. The technique holds promise for investigation of local myeloarchitectonics for neuroscientific and clinical studies.

Changes in white matter structural connectivity and cortical functional connectivity over the healthy adult lifespan
Adrian Tsang1,2,3, Catherine Lebel1,4, Signe Bray1,4, Brad Goodyear1,2,3, Roberto C. Sotero1, Cheryl McCreary1,3, and Richard Frayne1,2,3
1Department of Radiology, University of Calgary, Calgary, AB, Canada, 2Hotchkiss Brain Institute, Calgary, AB, Canada, 3Seaman Family MR Research Centre, Calgary, AB, Canada, 4Child and Adolescent Imaging Research Program, Alberta Children's Hospital Research Institute, Calgary, AB, Canada
This study investigates how both structural and functional connectivity (SC and FC) changes in the adult lifespan as well as to explore the relationship between measures that are commonly used for SC and FC in the context of normal aging. A multi-modal analysis using DTI and resting-state fMRI data was performed from 183 healthy participants aged 18 – 87 years. We found that fractional anisotropy (FA) and FC showed similar rate of change and correlation strengths with age in the 7 resting-state networks explored. However none of the SC measures showed significant correlations with FC measure. 

Diagnostic accuracy of MRS for Hereditary Neurodegeneration at 3T and 7T
Uzay E Emir1,2, Tianmeng Lyu3, Dinesh K Deelchand2, James M Joers2, Diane Hutter2, Christopher M Gomez4, Khalaf O Bushara5, Lynn E Eberly3, and Gulin Oz2
1FMRIB Centre, University of Oxford, Oxford, United Kingdom, 2Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States, 3Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN, United States, 4Department of Neurology, University of Chicago, Chicago, IL, United States, 5Department of Neurology, Medical School, University of Minnesota, Minneapolis, MN, United States
To evaluate diagnostic accuracy of state-of-the-art MRS in early neurodegenerative disease, we measured neurochemical profiles in the vermis, cerebellar hemisphere and brainstem of genetically confirmed subjects with spinocerebellar ataxia type 1 and controls by 3T and 7T 1H MRS. Concentrations of major metabolites obtained at 3T and 7T were strongly correlated. While 3T showed great potential by enabling detection of abnormal metabolite levels even in the presymptomatic stage, the increased sensitivity at 7T enabled group separation with higher significance and identification of subtle neurochemical alterations in early symptomatic disease stage more robustly than at 3T.

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