The Aging Brain

Room 701 A


Chairs: Matilde Inglese and Jeroen van der Grond


Prog #

16:00 373. Detecting Age-Related Changes in Resting CBF Using Casl MRI

Iris Asllani1, Ajna Borogovac, Truman R. Brown, Arjun Kumar, Yaakov Stern

1Columbia University, New York, New York, USA

CBF depression is considered an important correlate of normal aging which could at least partially explain the functional impairment in several processes in elderly. We compared CASL CBF images from young subjects with those from healthy elderly both at voxel- and ROI-wise level. As compared to the young group, the elderly subjects showed a signifiant decrease of ~ 24% in gray matter CBF, in good agreement with data from quantitative PET studies. Furthermore, the areas of CBF depression were consistent with their functional role in normal aging.

16:12 374. Increased Glial Energy Metabolism During Normal Brain Aging Assessed by Dynamic 13C NMR Spectroscopy

Fawzi Boumezbeur1, Graeme F. Mason1, Robin A. de Graaf1, Gary W. Cline2, Kevin L. Behar1, Gerald I. Shulman2, 3, Douglas L. Rothman1, Kitt Falk Petersen2

1Magnetic Resonance Research Center, Yale University, New Haven, USA; 2Yale School of Medicine, New Haven, USA; 3Howard Hughes Medical Institute, Yale School of Medicine, New Haven, USA

Age-related alterations in energy metabolism have been implicated as a key factor in many neurodegenerative diseases. In this study, 13C MR spectroscopy was combined with infusions of [1-13C]glucose and [2-13C]acetate to characterize quantitatively neuronal and astrocytic TCA cycle (VTCAn,VTCAa) as well as the glutamate-glutamine cycle (VNT) rates in healthy elderly and young volunteers. Major metabolic changes were measured: 30% increase of VTCAa (p=0.002), a 28% decrease of VTCAn (p=0.013) and a 24% decrease of VNT (p=0.03). Our results demonstrate that alterations in oxidative energy production in neurons and glia form a major characteristic of aging even in healthy elderly subjects.

16:24 375. Alterations of Brain Metabolites During Normal Aging: Correlation with Altered Energy Metabolism

Fawzi Boumezbeur1, Robin A. de Graaf1, Graeme F. Mason1, Gary W. Cline2, Kevin L. Behar1, Gerald I. Shulman2, 3, Douglas L. Rothman1, Kitt Falk Petersen2

1Magnetic Resonance Research Center, Yale University, New Haven, USA; 2Yale School of Medicine, New Haven, USA; 3Howard Hughes Medical Institute, Yale School of Medicine, New Haven, USA

For the past few years, many metabolite abnormalities in neurodegenerative diseases have been reported. In this study, we used short TE 1H MR to measure significant age-related changes in NAA (-12%), Glu (-13%) and Ins (+28%) in healthy old people. Further, we correlated the metabolite concentrations with energy synthesis and neurotransmission fluxes (VTCAa, VTCAn and VNT) measured in the same subjects using 13C MRS. Altogether, the results suggest a major evolution of the neuronal-astrocytic metabolic unit with normal aging and support the use of combined 1H and 13C MRS to study the role of brain metabolism in the etiology of neurodegenerative diseases

16:36 376. Voxel Based Analysis Derived from Fractional Anisotropy Images of White Matter Atrophy with Aging

Elisabetta Pagani1, Federica Agosta1, Domenico Caputo2, Massimo Filippi1, 3

1Scientific Institute and University Ospedale San Raffaele, Milan, Italy; 2Scientific Institute Fondazione Don Gnocchi, Milan, Milan, Italy; 3Scientific Institute Fondazione Don Gnocchi, Milan, Italy

In this study, a method to measure WM fiber bundles atrophy using diffusion tensor MRI was used. The age-related changes of the WM volumes from 84 healthy subjects, spanning seven decade of life, were obtained at a voxel-based resolution. A linear correlation was found between age and WM decline in superior-frontal and parietal fibers, anterior cingulum bundles, fornix, and cerebellar peduncles. By contrast, a quadratic regression model best fitted age-related WM loss in the genu of corpus callosum, pons bundles, and inferio-fronto-occipital/uncinate fasciculi. These findings provide evidence that aging of the WM takes different courses and there is considerable variation from region to region in how the effects of age are expressed.

16:48 377. Frontal-Subcortical Pathways for Working Memory: DTI Fiber Pathway Reduction in Healthy Older Subjects

Zhihao Li1, Anna Bacon Moore2, 3, Callie Tyner2, Xiaoping Hu1

1Emory Univ./Georgia Tech., Atlanta, Georgia, USA; 2Atlanta VAMC, Atlanta, Georgia, USA; 3Emory Univ., Atlanta, Georgia, USA

In the working memory associated brain network, reduction of structural connectivity is non-uniform with advancing age. This may be part of the neurobiological basis of the HAROLD (Hemispheric Asymmetry Reduction in Older Adults) effect.

17:00 378. Correlation of Fractional Anisotropy in Rhesus Monkeys with Age and Motor Function

Peter Andrew Hardy1, David Kennedy Powell1, Zhiming Zhang1

1University of Kentucky, Lexington, USA

Diffusion Tensor Imaging and Fractional Anisotropy analysis was used to correlate changes with age and with motor function in a cohort of healthy rhesus monkeys.

17:12 379. Ageing and Fractional Anisotropy: Global and Regional Results

Ramtilak Gattu1, Randall R. Benson2, 3, Balaji Myrtheunjayan1, Kristen Kennedy2, Naftaki Raz2, Zhifeng Kou4, Ewart M. Haacke5

1Wayne State University, Detroit, USA; 2Wayne State University School of Medicine, Detroit, USA; 3Detroit Medical Center, Detroit, USA; 4Wayne State University School of Medicine, Detroit, Michigan, USA; 5wayne state university, Detroit, USA

Few DTI studies demonstrated the age effect on fractional anisotropy (FA). We examined the effect of age on FA for whole brain white matter and in corpus callosum (CC). 70 healthy volunteers (aged 19-81, SD= 19.22 years) were imaged with DTI on a 1.5T scanner. All three regions of CC (genu, body, and Splenium) showed a slight decline in FA with age, with the greatest age effect in genu.  This equates to a drop of .006 per decade. We also found a trend towards greater variance in FA with age suggesting a heterogeneous adverse effect of ageing on WM fibers.

17:24 380. Different T1 Relaxation Brain Ageing Patterns Over the Human Lifespan: Frontal vs. Posterior Brain (75 Subjects)

Naoko Saito1, Hernan Jara1, Osamu Sakai1

1Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts, USA

Purpose: To evaluate the regional T1 changes over the human lifespan with quantitative MR imaging (Q-MRI). Methods: 75 subjects (0.5-87 years) obtained with the mixed-TSE pulse sequence were segmented into six segments: bilateral frontal, bilateral posterior and bilateral cerebellar segments leading to six T1 histograms per subject. Results: For all ages studied, T1 of frontal GM was consistently and bilaterally longer than T1 of posterior GM, by about 10%. Conclusion: T1 relaxation mechanisms in frontal GM are weaker than in posterior GM over the full human lifespan suggesting different frontal vs. posterior tissue micro-architecture and/or hydration level.

17:36 381.
 [Not Available]
Alterations of Globus Pallidus Magnetisation Transfer Ratio, T1, T2 in Primary Biliary Cirrhosis Patients and Controls: Relationship with Age and Autonomic Dysfunction

Kieren Grant Hollingsworth1, Julia L. Newton1, Benjamin S. Aribisala1, Peter Edward Thelwall1, Roy Taylor1, Andrew M. Blamire1, David E. Jones1

1Newcastle University, Newcastle Upon Tyne, UK

Primary Biliary Cirrhosis is an autoimmune liver disease resulting in debilitating fatigue for 50% of affected patients. One hypothesis postulates that the fatigue may originate from metal deposition in the globus pallidus (GP), measurable in the magnetization transfer ratio (MTR), but normal ageing effects have not been taken into account to date. This study investigated an age-matched group of 30 early-stage patients and 14 volunteers, assessing GP MTR, T1 and T2. The same age-related trend was found in patients and controls and GP T2 correlated with measures of autonomic dysfunction.

17:48 382. The Impact of Cerebrovascular Risk Factors on Brain Tissue Changes: A MTI Study

Stefan Ropele1, Christian Enzinger1, Gernot Reishofer1, Reinhold Schmidt1, Franz Fazekas1

1Medical University Graz, Graz, Austria

The study goal was to explore if specific cerebrovascular risk factors may have an impact on the cerebral tissue matrix as assessed by the magnetization transfer ratio (MTR). Measurement of the MTR was done in white matter hyperintensities and in normal appearing brain tissue (NABT) of 328 neurologically asymptomatic elderly subjects. A multivariate regression model was used to study the effect of a large battery of possible risk factors on global and lesional MTR changes. Our results suggest that MTR changes in NABT are related predominantly to the ageing process per se. Diabetes and hypertension may exert some additional minor effects.