Kwun Kei Ng¹, June C. Lo¹, Michael W.L. Chee¹, and Juan Zhou^1,2
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.

Byeong-Yeul Lee¹, Xiao-Hong Zhu¹, and Wei Chen^1
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. 

Zixuan Lin¹, Marilyn Albert², Peiying Liu³, Anja Soldan², Abhay Moghekar³, Shin-Lei Peng⁴, Michael Miller¹, Peter van Zijl³, and Hanzhang Lu^3
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.

Daniel J Cox^1,2, Hamied A Haroon², Daniela Montaldi¹, and Laura M Parkes^2
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.

Janet Guo¹, Ailing Lin^1,2, and Vikas Bakshi^1
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.  

Alex Bhogal¹, Jill B de Vis¹, Jeroen C.W. Siero¹, Esben T Petersen², Peter R. Luijten¹, Jeroen Hendrikse¹, Marielle E.P. Philippens³, and Hans Hoogduin^4
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. 

Andrew Hale¹, Penny Gowland¹, Paul Greenhaff², and Susan Francis^1
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.

Gisela E Hagberg^1,2, Jonas Bause¹, Thomas Ethofer^2,3, Philipp Ehses¹, Thomas Dresler³, G Shajan¹, Rolf Pohmann¹, Cornelia Herbert³, Andreas Fallgatter³, Christoph Laske³, Marina Pavlova², and Klaus Scheffler^1,2
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.

Adrian Tsang^1,2,3, Catherine Lebel^1,4, Signe Bray^1,4, Brad Goodyear^1,2,3, Roberto C. Sotero¹, Cheryl McCreary^1,3, and Richard Frayne^1,2,3
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. 

Uzay E Emir^1,2, Tianmeng Lyu³, Dinesh K Deelchand², James M Joers², Diane Hutter², Christopher M Gomez⁴, Khalaf O Bushara⁵, Lynn E Eberly³, and Gulin Oz^2
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.