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Advanced Overview of Biomarkers and Techniques for Early Diagnosis of Alzheimer's Disease. Cell Mol Neurobiol 2023:10.1007/s10571-023-01330-y. [PMID: 36847930 DOI: 10.1007/s10571-023-01330-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 02/15/2023] [Indexed: 03/01/2023]
Abstract
The development of early non-invasive diagnosis methods and identification of novel biomarkers are necessary for managing Alzheimer's disease (AD) and facilitating effective prognosis and treatment. AD has multi-factorial nature and involves complex molecular mechanism, which causes neuronal degeneration. The primary challenges in early AD detection include patient heterogeneity and lack of precise diagnosis at the preclinical stage. Several cerebrospinal fluid (CSF) and blood biomarkers have been proposed to show excellent diagnosis ability by identifying tau pathology and cerebral amyloid beta (Aβ) for AD. Intense research endeavors are being made to develop ultrasensitive detection techniques and find potent biomarkers for early AD diagnosis. To mitigate AD worldwide, understanding various CSF biomarkers, blood biomarkers, and techniques that can be used for early diagnosis is imperative. This review attempts to provide information regarding AD pathophysiology, genetic and non-genetic factors associated with AD, several potential blood and CSF biomarkers, like neurofilament light, neurogranin, Aβ, and tau, along with biomarkers under development for AD detection. Besides, numerous techniques, such as neuroimaging, spectroscopic techniques, biosensors, and neuroproteomics, which are being explored to aid early AD detection, have been discussed. The insights thus gained would help in finding potential biomarkers and suitable techniques for the accurate diagnosis of early AD before cognitive dysfunction.
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Goukasian N, Porat S, Blanken A, Avila D, Zlatev D, Hurtz S, Hwang KS, Pierce J, Joshi SH, Woo E, Apostolova LG. Cognitive Correlates of Hippocampal Atrophy and Ventricular Enlargement in Adults with or without Mild Cognitive Impairment. Dement Geriatr Cogn Dis Extra 2019; 9:281-293. [PMID: 31572424 PMCID: PMC6751474 DOI: 10.1159/000490044] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 05/15/2018] [Indexed: 12/25/2022] Open
Abstract
We analyzed structural magnetic resonance imaging data from 58 cognitively normal and 101 mild cognitive impairment subjects. We used a general linear regression model to study the association between cognitive performance with hippocampal atrophy and ventricular enlargement using the radial distance method. Bilateral hippocampal atrophy was associated with baseline and longitudinal memory performance. Left hippocampal atrophy predicted longitudinal decline in visuospatial function. The multidomain ventricular analysis did not reveal any significant predictors.
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Affiliation(s)
- Naira Goukasian
- University of Vermont, Larner College of Medicine, Burlington, Vermont, USA
| | - Shai Porat
- Department of Psychology, University of Southern California, Los Angeles, California, USA
| | - Anna Blanken
- Department of Psychology, University of Southern California, Los Angeles, California, USA
| | - David Avila
- Irvine School of Medicine, University of California, Irvine, California, USA
| | - Dimitar Zlatev
- Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Sona Hurtz
- Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Kristy S Hwang
- Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jonathan Pierce
- Department of Neurology, University of California, Los Angeles, California, USA
| | - Shantanu H Joshi
- Department of Neurology, University of California, Los Angeles, California, USA
| | - Ellen Woo
- Department of Neurology, University of California, Los Angeles, California, USA
| | - Liana G Apostolova
- Department of Neurology, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Todd KL, Brighton T, Norton ES, Schick S, Elkins W, Pletnikova O, Fortinsky RH, Troncoso JC, Molfese PJ, Resnick SM, Conover JC. Ventricular and Periventricular Anomalies in the Aging and Cognitively Impaired Brain. Front Aging Neurosci 2018; 9:445. [PMID: 29379433 PMCID: PMC5771258 DOI: 10.3389/fnagi.2017.00445] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 12/26/2017] [Indexed: 12/14/2022] Open
Abstract
Ventriculomegaly (expansion of the brain’s fluid-filled ventricles), a condition commonly found in the aging brain, results in areas of gliosis where the ependymal cells are replaced with dense astrocytic patches. Loss of ependymal cells would compromise trans-ependymal bulk flow mechanisms required for clearance of proteins and metabolites from the brain parenchyma. However, little is known about the interplay between age-related ventricle expansion, the decline in ependymal integrity, altered periventricular fluid homeostasis, abnormal protein accumulation and cognitive impairment. In collaboration with the Baltimore Longitudinal Study of Aging (BLSA) and Alzheimer’s Disease Neuroimaging Initiative (ADNI), we analyzed longitudinal structural magnetic resonance imaging (MRI) and subject-matched fluid-attenuated inversion recovery (FLAIR) MRI and periventricular biospecimens to map spatiotemporally the progression of ventricle expansion and associated periventricular edema and loss of transependymal exchange functions in healthy aging individuals and those with varying degrees of cognitive impairment. We found that the trajectory of ventricle expansion and periventricular edema progression correlated with degree of cognitive impairment in both speed and severity, and confirmed that areas of expansion showed ventricle surface gliosis accompanied by edema and periventricular accumulation of protein aggregates, suggesting impaired clearance mechanisms in these regions. These findings reveal pathophysiological outcomes associated with normal brain aging and cognitive impairment, and indicate that a multifactorial analysis is best suited to predict and monitor cognitive decline.
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Affiliation(s)
- Krysti L Todd
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Tessa Brighton
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Emily S Norton
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Samuel Schick
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Wendy Elkins
- Laboratory of Behavioral Neuroscience, Intramural Research Program, National Institute on Aging, Baltimore, MD, United States
| | - Olga Pletnikova
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Richard H Fortinsky
- UConn Center on Aging, University of Connecticut School of Medicine, Farmington, CT, United States
| | - Juan C Troncoso
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Peter J Molfese
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, United States
| | - Susan M Resnick
- Laboratory of Behavioral Neuroscience, Intramural Research Program, National Institute on Aging, Baltimore, MD, United States
| | - Joanne C Conover
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
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Magisetty O, Dowlathabad MR, Raichurkar KP, Mannar SN. First magenetic resonance imaging studies on aluminium maltolate-treated aged New Zealand rabbits: an Alzheimer's animal model. Psychogeriatrics 2016; 16:263-7. [PMID: 26419490 DOI: 10.1111/psyg.12158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 02/23/2015] [Accepted: 08/12/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Alzheimer's disease is a devastative neurodegenerative disorder. To date, there has been no animal model that could unravel the complete disease pathology. Magnetic resonance imaging has played a pivotal role in the quantitative assessment of brain tissue atrophy for a few decades. In particular, temporal lobe atrophy and ventricular dilatation have been found to be sensitive in Alzheimer's disease. METHODS The present study focused on the replication of these crucial pathological events to enable disease progression to be diagnosed at an early stage and stopped through the use of potential therapeutic strategies. RESULT The objective of this study was to show temporal lobe atrophy and ventricular dilatation in aluminium maltolate-treated aged New Zealand rabbit, and our study was able to demonstrate this for the first time. CONCLUSION The present study makes this animal model a substantial one for further molecular level studies and opens up new targets for potential therapeutic strategies.
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Affiliation(s)
- Obulesu Magisetty
- Department of Materials Science, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki-305-8573, Japan
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Jernerén F, Elshorbagy AK, Oulhaj A, Smith SM, Refsum H, Smith AD. Brain atrophy in cognitively impaired elderly: the importance of long-chain ω-3 fatty acids and B vitamin status in a randomized controlled trial. Am J Clin Nutr 2015; 102:215-21. [PMID: 25877495 DOI: 10.3945/ajcn.114.103283] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 03/19/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Increased brain atrophy rates are common in older people with cognitive impairment, particularly in those who eventually convert to Alzheimer disease. Plasma concentrations of omega-3 (ω-3) fatty acids and homocysteine are associated with the development of brain atrophy and dementia. OBJECTIVE We investigated whether plasma ω-3 fatty acid concentrations (eicosapentaenoic acid and docosahexaenoic acid) modify the treatment effect of homocysteine-lowering B vitamins on brain atrophy rates in a placebo-controlled trial (VITACOG). DESIGN This retrospective analysis included 168 elderly people (≥70 y) with mild cognitive impairment, randomly assigned either to placebo (n = 83) or to daily high-dose B vitamin supplementation (folic acid, 0.8 mg; vitamin B-6, 20 mg; vitamin B-12, 0.5 mg) (n = 85). The subjects underwent cranial magnetic resonance imaging scans at baseline and 2 y later. The effect of the intervention was analyzed according to tertiles of baseline ω-3 fatty acid concentrations. RESULTS There was a significant interaction (P = 0.024) between B vitamin treatment and plasma combined ω-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid) on brain atrophy rates. In subjects with high baseline ω-3 fatty acids (>590 μmol/L), B vitamin treatment slowed the mean atrophy rate by 40.0% compared with placebo (P = 0.023). B vitamin treatment had no significant effect on the rate of atrophy among subjects with low baseline ω-3 fatty acids (<390 μmol/L). High baseline ω-3 fatty acids were associated with a slower rate of brain atrophy in the B vitamin group but not in the placebo group. CONCLUSIONS The beneficial effect of B vitamin treatment on brain atrophy was observed only in subjects with high plasma ω-3 fatty acids. It is also suggested that the beneficial effect of ω-3 fatty acids on brain atrophy may be confined to subjects with good B vitamin status. The results highlight the importance of identifying subgroups likely to benefit in clinical trials. This trial was registered at www.controlled-trials.com as ISRCTN94410159.
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Affiliation(s)
- Fredrik Jernerén
- From the Oxford Project to Investigate Memory and Ageing (OPTIMA), Department of Pharmacology, University of Oxford, Oxford, United Kingdom;
| | - Amany K Elshorbagy
- From the Oxford Project to Investigate Memory and Ageing (OPTIMA), Department of Pharmacology, University of Oxford, Oxford, United Kingdom; Department of Physiology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt
| | - Abderrahim Oulhaj
- Institute of Public Health, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Stephen M Smith
- Functional Magnetic Resonance Imaging of the Brain Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom; and
| | - Helga Refsum
- From the Oxford Project to Investigate Memory and Ageing (OPTIMA), Department of Pharmacology, University of Oxford, Oxford, United Kingdom; Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - A David Smith
- From the Oxford Project to Investigate Memory and Ageing (OPTIMA), Department of Pharmacology, University of Oxford, Oxford, United Kingdom
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Mak E, Su L, Williams GB, Watson R, Firbank M, Blamire AM, O'Brien JT. Longitudinal assessment of global and regional atrophy rates in Alzheimer's disease and dementia with Lewy bodies. NEUROIMAGE-CLINICAL 2015; 7:456-62. [PMID: 25685712 PMCID: PMC4325088 DOI: 10.1016/j.nicl.2015.01.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 01/13/2015] [Accepted: 01/30/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND & OBJECTIVE Percent whole brain volume change (PBVC) measured from serial MRI scans is widely accepted as a sensitive marker of disease progression in Alzheimer's disease (AD). However, the utility of PBVC in the differential diagnosis of dementia remains to be established. We compared PBVC in AD and dementia with Lewy bodies (DLB), and investigated associations with clinical measures. METHODS 72 participants (14 DLBs, 25 ADs, and 33 healthy controls (HCs)) underwent clinical assessment and 3 Tesla T1-weighted MRI at baseline and repeated at 12 months. We used FSL-SIENA to estimate PBVC for each subject. Voxelwise analyses and ANCOVA compared PBVC between DLB and AD, while correlational tests examined associations of PBVC with clinical measures. RESULTS AD had significantly greater atrophy over 1 year (1.8%) compared to DLB (1.0%; p = 0.01) and HC (0.9%; p < 0.01) in widespread regions of the brain including periventricular areas. PBVC was not significantly different between DLB and HC (p = 0.95). There were no differences in cognitive decline between DLB and AD. In the combined dementia group (AD and DLB), younger age was associated with higher atrophy rates (r = 0.49, p < 0.01). CONCLUSIONS AD showed a faster rate of global brain atrophy compared to DLB, which had similar rates of atrophy to HC. Among dementia subjects, younger age was associated with accelerated atrophy, reflecting more aggressive disease in younger people. PBVC could aid in differentiating between DLB and AD, however its utility as an outcome marker in DLB is limited.
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Affiliation(s)
- Elijah Mak
- Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Li Su
- Department of Psychiatry, University of Cambridge, Cambridge, UK
| | | | - Rosie Watson
- Department of Aged Care, The Royal Melbourne Hospital, Melbourne, Australia ; Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle, UK
| | - Michael Firbank
- Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle, UK
| | - Andrew M Blamire
- Institute of Cellular Medicine & Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle, UK
| | - John T O'Brien
- Department of Psychiatry, University of Cambridge, Cambridge, UK
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Kantarci K. Magnetic resonance markers for early diagnosis and progression of Alzheimer’s disease. Expert Rev Neurother 2014; 5:663-70. [PMID: 16162090 DOI: 10.1586/14737175.5.5.663] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
With increasing life expectancy, the early diagnosis and treatment of Alzheimer's disease has become critical in sustaining a healthy society. Noninvasive markers of disease progression starting from the earliest stages of pathologic involvement are required for determining the effectiveness of putative disease-modifying therapies that are under development. Cross-sectional and longitudinal studies indicate that magnetic resonance-based volume measurements of atrophy are potential markers of the progression of Alzheimer's disease, starting from the preclinical stages. Other magnetic resonance techniques that are sensitive to the different aspects of Alzheimer's disease pathology, such as biochemical ((proton) magnetic resonance spectroscopy), microstructural (diffusion magnetic resonance imaging), functional (functional magnetic resonance imaging) and blood flow (perfusion magnetic resonance imaging) changes, have not been as extensively studied longitudinally. Recent efforts of imaging amyloid plaques with magnetic resonance imaging generate the prospect for in vivo imaging of the pathologic substrate of Alzheimer's disease in the future. In order for magnetic resonance modalities to qualify as surrogate markers for early diagnosis and progression of Alzheimer's disease, multicenter longitudinal studies are needed.
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Affiliation(s)
- Kejal Kantarci
- Department of Radiology, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905, USA.
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Wischik CM, Harrington CR, Storey JMD. Tau-aggregation inhibitor therapy for Alzheimer's disease. Biochem Pharmacol 2013; 88:529-39. [PMID: 24361915 DOI: 10.1016/j.bcp.2013.12.008] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 12/08/2013] [Accepted: 12/09/2013] [Indexed: 12/22/2022]
Abstract
Many trials of drugs aimed at preventing or clearing β-amyloid pathology have failed to demonstrate efficacy in recent years and further trials continue with drugs aimed at the same targets and mechanisms. The Alzheimer neurofibrillary tangle is composed of tau and the core of its constituent filaments are made of a truncated fragment from the repeat domain of tau. This truncated tau can catalyse the conversion of normal soluble tau into aggregated oligomeric and fibrillar tau which, in turn, can spread to neighbouring neurons. Tau aggregation is not a late-life process and onset of Braak stage 1 peaks in people in their late 40s or early 50s. Tau aggregation pathology at Braak stage 1 or beyond affects 50% of the population over the age of 45. The initiation of tau aggregation requires its binding to a non-specific substrate to expose a high affinity tau-tau binding domain and it is self-propagating thereafter. The initiating substrate complex is most likely formed as a consequence of a progressive loss of endosomal-lysosomal processing of neuronal proteins, particularly of membrane proteins from mitochondria. Mutations in the APP/presenilin membrane complex may simply add to the age-related endosomal-lysosomal processing failure, bringing forward, but not directly causing, the tau aggregation cascade in carriers. Methylthioninium chloride (MTC), the first identified tau aggregation inhibitor (TAI), offers an alternative to the amyloid approach. Phase 3 trials are underway with a novel stabilized reduced form of methylthioninium (LMTX) that has improved tolerability and absorption.
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Affiliation(s)
- Claude M Wischik
- TauRx Therapeutics Ltd., Singapore; School of Medicine and Dentistry, University of Aberdeen, Scotland, United Kingdom.
| | - Charles R Harrington
- TauRx Therapeutics Ltd., Singapore; School of Medicine and Dentistry, University of Aberdeen, Scotland, United Kingdom
| | - John M D Storey
- TauRx Therapeutics Ltd., Singapore; Department of Chemistry, University of Aberdeen, Scotland, United Kingdom
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Mullins D, Daly E, Simmons A, Beacher F, Foy CML, Lovestone S, Hallahan B, Murphy KC, Murphy DG. Dementia in Down's syndrome: an MRI comparison with Alzheimer's disease in the general population. J Neurodev Disord 2013; 5:19. [PMID: 23962297 PMCID: PMC3765707 DOI: 10.1186/1866-1955-5-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 07/30/2013] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Down's syndrome (DS) is the most common genetic cause of intellectual disability. People with DS are at an increased risk of Alzheimer's disease (AD) compared to the general population. Neuroimaging studies of AD have focused on medial temporal structures; however, to our knowledge, no in vivo case-control study exists comparing the anatomy of dementia in DS to people with AD in the general population. We therefore compared the in vivo brain anatomy of people with DS and dementia (DS+) to those with AD in the general population. METHOD Using MRI in 192 adults, we compared the volume of whole brain matter, lateral ventricles, temporal lobes and hippocampus in DS subjects with and without dementia (DS+, DS-), to each other and to three non-DS groups. These included one group of individuals with AD and two groups of controls (each age-matched for their respective DS and general population AD cohorts). RESULTS AD and DS+ subjects showed significant reductions in the volume of the whole brain, hippocampus and temporal lobes and a significant elevation in the volume of the lateral ventricle, compared to their non-demented counterparts. People with DS+ had a smaller reduction in temporal lobe volume compared to individuals with AD. CONCLUSIONS DS+ and AD subjects have a significant reduction in volume of the same brain regions. We found preliminary evidence that DS individuals may be more sensitive to tissue loss than others and have less 'cognitive reserve'.
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Affiliation(s)
- Diane Mullins
- Department of Forensic and Neurodevelopmental Sciences, Section of Brain Maturation, Institute of Psychiatry, De Crespigny Park, London, England, UK
- Department of Psychiatry, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland
| | - Eileen Daly
- Department of Forensic and Neurodevelopmental Sciences, Section of Brain Maturation, Institute of Psychiatry, De Crespigny Park, London, England, UK
| | - Andrew Simmons
- Department of Neuroimaging, Institute of Psychiatry, King’s College London, London, England, UK
- NIHR Biomedical Research Centre for Medical Health at the South London and Maudsley NHS Foundation Trust and King’s College London, Institute of Psychiatry, London, England, UK
| | - Felix Beacher
- Department of Forensic and Neurodevelopmental Sciences, Section of Brain Maturation, Institute of Psychiatry, De Crespigny Park, London, England, UK
| | - Catherine ML Foy
- Section of Old Age Psychiatry, Institute of Psychiatry, De Crespigny Park, London, England, UK
| | - Simon Lovestone
- NIHR Biomedical Research Centre for Medical Health at the South London and Maudsley NHS Foundation Trust and King’s College London, Institute of Psychiatry, London, England, UK
- MRC Centre for Neurodegeneration Research, Section of Old Age Psychiatry, Institute of Psychiatry, King’s College London, London, England, UK
| | - Brian Hallahan
- Department of Psychiatry, Clinical Science Institute, National University of Ireland Galway, Galway, Ireland
| | - Kieran C Murphy
- Department of Psychiatry, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland
| | - Declan G Murphy
- Department of Forensic and Neurodevelopmental Sciences, Section of Brain Maturation, Institute of Psychiatry, De Crespigny Park, London, England, UK
- NIHR Biomedical Research Centre for Medical Health at the South London and Maudsley NHS Foundation Trust and King’s College London, Institute of Psychiatry, London, England, UK
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Krueger G, Granziera C, Jack CR, Gunter JL, Littmann A, Mortamet B, Kannengiesser S, Sorensen AG, Ward CP, Reyes DA, Britson PJ, Fischer H, Bernstein MA. Effects of MRI scan acceleration on brain volume measurement consistency. J Magn Reson Imaging 2012; 36:1234-40. [PMID: 22570196 PMCID: PMC3432691 DOI: 10.1002/jmri.23694] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 04/03/2012] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To evaluate the effects of recent advances in magnetic resonance imaging (MRI) radiofrequency (RF) coil and parallel imaging technology on brain volume measurement consistency. MATERIALS AND METHODS In all, 103 whole-brain MRI volumes were acquired at a clinical 3T MRI, equipped with a 12- and 32-channel head coil, using the T1-weighted protocol as employed in the Alzheimer's Disease Neuroimaging Initiative study with parallel imaging accelerations ranging from 1 to 5. An experienced reader performed qualitative ratings of the images. For quantitative analysis, differences in composite width (CW, a measure of image similarity) and boundary shift integral (BSI, a measure of whole-brain atrophy) were calculated. RESULTS Intra- and intersession comparisons of CW and BSI measures from scans with equal acceleration demonstrated excellent scan-rescan accuracy, even at the highest acceleration applied. Pairs-of-scans acquired with different accelerations exhibited poor scan-rescan consistency only when differences in the acceleration factor were maximized. A change in the coil hardware between compared scans was found to bias the BSI measure. CONCLUSION The most important findings are that the accelerated acquisitions appear to be compatible with the assessment of high-quality quantitative information and that for highest scan-rescan accuracy in serial scans the acquisition protocol should be kept as consistent as possible over time.
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Affiliation(s)
- Gunnar Krueger
- Siemens Schweiz AG, Healthcare Sector IM&WS, Renens, Switzerland.
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Morris JC, Kimberly A, Quaid K, Holtzman DM, Kantarci K, Kaye J, Reiman EM, Klunk WE, Siemers ER. Role of biomarkers in studies of presymptomatic Alzheimer's disease. Alzheimers Dement 2012; 1:145-51. [PMID: 19595847 DOI: 10.1016/j.jalz.2005.09.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Accepted: 09/29/2005] [Indexed: 11/15/2022]
Abstract
BACKGROUND Biomarkers that have been developed largely for the study of patients with clinically diagnosed Alzheimer's disease (AD) can also be used in the study of cognitively normal individuals who may harbor underlying AD pathology. METHODS A meeting of invited experts on AD biomarkers was held on November 11 and 12, 2004 to review currently available data and to discuss unmet needs for biomarker research in presymptomatic AD. RESULTS Neuroimaging biomarkers have been studied to some extent in subjects at risk for AD. These imaging techniques include volumetric magnetic resonance imaging and positron emission tomography using either fluorodeoxyglucose or newer ligands that bind directly to amyloid plaque. Similarly, biochemical measures from cerebrospinal fluid or other physiologic fluids are emerging as potentially useful tools. Such biomarkers may be used either as diagnostic tools or as indicators of disease severity when followed longitudinally. A clinical diagnosis of asymptomatic individuals using biomarkers and studies involving asymptomatic subjects may raise logistical and ethical concerns. CONCLUSIONS The technical development of biomarkers that are used for presymptomatic AD diagnosis and for longitudinally measuring disease severity is evolving rapidly. Ethical and privacy considerations must be made before such biomarkers can be applied routinely to asymptomatic populations.
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Affiliation(s)
- John C Morris
- Washington University in St. Louis, School of Medicine, Department of Neurology, Alzheimer's Disease Research Center, MO, USA
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12
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Lessov-Schlaggar CN, Hardin J, DeCarli C, Krasnow RE, Reed T, Wolf PA, Swan GE, Carmelli D. Longitudinal genetic analysis of brain volumes in normal elderly male twins. Neurobiol Aging 2012; 33:636-44. [PMID: 20630620 PMCID: PMC2970700 DOI: 10.1016/j.neurobiolaging.2010.06.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 05/31/2010] [Accepted: 06/05/2010] [Indexed: 11/17/2022]
Abstract
This study investigated the role of genetic and environmental influences on individual differences in brain volumes measured at 2 time points in normal elderly males from the National Heart, Lung, and Blood Institute Twin Study. The magnetic resonance imaging (MRI) scans were conducted 4 years apart on 33 monozygotic and 33 dizygotic male twin pairs, aged 68 to 77 years when first scanned. Volumetric measures of total brain and total cerebrospinal fluid were significantly heritable at baseline (over 70%). For both volumes genetic influences at follow-up were entirely accounted for by genetic influences at baseline, suggesting that the same genetic factors influence variability in brain volume at each time of assessment. Variability in 4-year volume change was due to shared and individual-specific environmental influences. There was little evidence for heritable influences on change measures. These results suggest that variation in longitudinal change of some brain volume measures may have different underlying genetic and environmental architecture from variation in repeat cross-sectional measures, which could have implications for intervention strategies for age-related illness associated with brain morphology. The results of this study are discussed in the context of the small sample size and associated limitations of statistical power.
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Affiliation(s)
| | - Jill Hardin
- Department of Epidemiology & Biostatistics, University of California San Francisco, San Francisco, CA 94158, USA
| | - Charles DeCarli
- Department of Neurology and Center for Neuroscience, University of California Davis, Sacramento, CA 95817, USA
| | - Ruth E. Krasnow
- Center for Health Sciences, SRI International, Menlo Park, CA 94025, USA
| | - Terry Reed
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Philip A. Wolf
- Department of Neurology, Boston University, Boston, MA 02118, USA
| | - Gary E. Swan
- Center for Health Sciences, SRI International, Menlo Park, CA 94025, USA
| | - Dorit Carmelli
- Center for Health Sciences, SRI International, Menlo Park, CA 94025, USA
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Venneri A, Shanks MF. Using MRI neuroimaging methods to detect treatment responses in Alzheimer’s disease. Neurodegener Dis Manag 2011. [DOI: 10.2217/nmt.11.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SUMMARY The rapid development of neuroimaging outcome measures for monitoring treatment effects and disease progression in neurological disorders presents both opportunities and hazards. An overview of functional MRI studies of regional brain activation using cognitive activation and resting state paradigms in mild cognitive impairment and Alzheimer’s disease indicates that this method can detect group treatment responses in the absence of overt behavioral change, as well as the kinetic and dynamic effects of the available symptomatic treatment compounds. Structural and spectroscopic MRI methods offer the prospect of objective and clinically meaningful assessment of progressive neuropathological changes and their modification through intervention. Including imaging parameters adequately powers small group studies of drug effects with additional advantages for more robust patient characterization and staging. These techniques should play an increasingly important role at an earlier stage of treatment evaluation, but the need for expert implementation and analysis means that clinical applications in individual cases are still in development.
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Affiliation(s)
| | - Michael F Shanks
- Department of Neuroscience, University of Sheffield, UK
- NHS Highland, UK and Clinical Neuroscience Centre, University of Hull, UK
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Sidiropoulos C, Jafari-Khouzani K, Soltanian-Zadeh H, Mitsias P, Alexopoulos P, Richter-Schmidinger T, Reichel M, Lewczuk P, Doerfler A, Kornhuber J. Influence of brain-derived neurotrophic factor and apolipoprotein E genetic variants on hemispheric and lateral ventricular volume of young healthy adults. Acta Neuropsychiatr 2011; 23:132-8. [PMID: 21701702 PMCID: PMC3119566 DOI: 10.1111/j.1601-5215.2011.00546.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Brain-derived neurotrophic factor (BDNF) and apolipoprotein E (ApoE) are thought to be implicated in a variety of neuronal processes, including cell growth, resilience to noxious stimuli and synaptic plasticity. A Val to Met substitution at codon 66 in the BDNF protein has been associated with a variety of neuropsychiatric conditions. The ApoE4 allele is considered a risk factor for late-onset Alzheimer's disease, but its effects on young adults are less clear. We sought to investigate the effects of those two polymorphisms on hemispheric and lateral ventricular volumes of young healthy adults. METHODS Hemispheric and lateral ventricular volumes of 144 healthy individuals, aged 19-35 years, were measured using high resolution magnetic resonance imaging and data were correlated with BDNF and ApoE genotypes. RESULTS There were no correlations between BDNF or ApoE genotype and hemispheric or lateral ventricular volumes. CONCLUSION These findings indicate that it is unlikely that either the BDNF Val66Met or ApoE polymorphisms exert any significant effect on hemispheric or lateral ventricular volume. However, confounding epistatic genetic effects as well as relative insensitivity of the volumetric methods used cannot be ruled out. Further imaging analyses are warranted to better define any genetic influence of the BDNF Val6Met and ApoE polymorphism on brain structure of young healthy adults.
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Wollenweber FA, Schomburg R, Probst M, Schneider V, Hiry T, Ochsenfeld A, Mueller M, Dillmann U, Fassbender K, Behnke S. Width of the third ventricle assessed by transcranial sonography can monitor brain atrophy in a time- and cost-effective manner--results from a longitudinal study on 500 subjects. Psychiatry Res 2011; 191:212-6. [PMID: 21288698 DOI: 10.1016/j.pscychresns.2010.09.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 09/12/2010] [Accepted: 09/23/2010] [Indexed: 11/18/2022]
Abstract
Ventricular width and its enlargement over time are discussed as promising markers for preclinical brain atrophy. The aim of our study was to define whether brain atrophy can reliably be monitored by transcranial ultrasound (TCS). In a prospective longitudinal trial over 5years, 500 healthy persons were examined by a standardized protocol with TCS in addition to an extensive cognitive testing using the Consortium to Establish a Registry of Alzheimer's Disease - Neuropsychological Testing (CERAD-NP). TCS displayed the third ventricle in 96% of all cases at the follow-up with a high intra-individual reproducibility and excellent inter-rater coefficient (0.992). The mean diameter of the third ventricle in subjects with a cognitive decline was significantly wider (6mm±2) than in subjects with normal cognitive testing results (4.6mm±1.8). We demonstrated that the width of the third ventricle, as a marker of brain atrophy can reliably be monitored by using TCS as a non-invasive, time- and cost-effective method. We provide evidence that the assessed width of the third ventricle can differentiate between subjects with a normal cognitive performance and subjects with a cognitive decline. TCS may be a useful screening tool in the early diagnosis of cognitive decline.
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Affiliation(s)
- Frank Arne Wollenweber
- Department of Neurology, University of the Saarland, Kirrberger Str., 66421 Homburg Saar, Germany.
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Tate DF, Khedraki R, McCaffrey D, Branson D, Dewey J. The role of medical imaging in defining CNS abnormalities associated with HIV-infection and opportunistic infections. Neurotherapeutics 2011; 8:103-16. [PMID: 21274690 PMCID: PMC3075743 DOI: 10.1007/s13311-010-0010-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In this review of the current literature, we examine the role of medical imaging in providing new and relevant information on central nervous system (CNS) injury associated with human immunodeficiency virus (HIV) infection and various clinical manifestations of this injury. Common imaging modalities used to examine CNS injury in HIV infection include structural magnetic resonance imaging, magnetic resonance spectroscopy, diffusion tensor imaging, functional MRI, and positron emissions tomography. Clinical implications for the findings are discussed for each of these modalities individually and collectively. In addition, the direction for future studies is suggested in an attempt to provide possible methods that might answer the many questions that remain to be answered on the evolution and progression of CNS injury in the context of HIV infection.
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Affiliation(s)
- David F Tate
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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Okonkwo OC, Alosco ML, Jerskey BA, Sweet LH, Ott BR, Tremont G. Cerebral atrophy, apolipoprotein E varepsilon4, and rate of decline in everyday function among patients with amnestic mild cognitive impairment. Alzheimers Dement 2010; 6:404-11. [PMID: 20813341 DOI: 10.1016/j.jalz.2010.02.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 02/20/2010] [Accepted: 02/22/2010] [Indexed: 12/25/2022]
Abstract
BACKGROUND Patients with amnestic mild cognitive impairment (MCI) demonstrate decline in everyday function. In this study, we investigated whether whole brain atrophy and apolipoprotein E (APOE) genotype are associated with the rate of functional decline in MCI. METHODS Participants were 164 healthy controls, 258 MCI patients, and 103 patients with mild Alzheimer's disease (AD), enrolled in the Alzheimer's Disease Neuroimaging Initiative. They underwent brain MRI scans, APOE genotyping, and completed up to six biannual Functional Activities Questionnaire (FAQ) assessments. Random effects regressions were used to examine trajectories of decline in FAQ across diagnostic groups, and to test the effects of ventricle-to-brain ratio (VBR) and APOE genotype on FAQ decline among MCI patients. RESULTS Rate of decline in FAQ among MCI patients was intermediate between that of controls and mild AD patients. Patients with MCI who converted to mild AD declined faster than those who remained stable. Among MCI patients, increased VBR and possession of any APOE varepsilon4 allele were associated with faster rate of decline in FAQ. In addition, there was a significant VBR by APOE varepsilon4 interaction such that patients who were APOE varepsilon4 positive and had increased atrophy experienced the fastest decline in FAQ. CONCLUSIONS Functional decline occurs in MCI, particularly among patients who progress to mild AD. Brain atrophy and APOE varepsilon4 positivity are associated with such declines, and patients who have elevated brain atrophy and are APOE varepsilon4 positive are at greatest risk of functional degradation. These findings highlight the value of genetic and volumetric MRI information as predictors of functional decline, and thus disease progression, in MCI.
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Affiliation(s)
- Ozioma C Okonkwo
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Smith AD, Smith SM, de Jager CA, Whitbread P, Johnston C, Agacinski G, Oulhaj A, Bradley KM, Jacoby R, Refsum H. Homocysteine-lowering by B vitamins slows the rate of accelerated brain atrophy in mild cognitive impairment: a randomized controlled trial. PLoS One 2010; 5:e12244. [PMID: 20838622 PMCID: PMC2935890 DOI: 10.1371/journal.pone.0012244] [Citation(s) in RCA: 461] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 07/22/2010] [Indexed: 11/18/2022] Open
Abstract
Background An increased rate of brain atrophy is often observed in older subjects, in particular those who suffer from cognitive decline. Homocysteine is a risk factor for brain atrophy, cognitive impairment and dementia. Plasma concentrations of homocysteine can be lowered by dietary administration of B vitamins. Objective To determine whether supplementation with B vitamins that lower levels of plasma total homocysteine can slow the rate of brain atrophy in subjects with mild cognitive impairment in a randomised controlled trial (VITACOG, ISRCTN 94410159). Methods and Findings Single-center, randomized, double-blind controlled trial of high-dose folic acid, vitamins B6 and B12 in 271 individuals (of 646 screened) over 70 y old with mild cognitive impairment. A subset (187) volunteered to have cranial MRI scans at the start and finish of the study. Participants were randomly assigned to two groups of equal size, one treated with folic acid (0.8 mg/d), vitamin B12 (0.5 mg/d) and vitamin B6 (20 mg/d), the other with placebo; treatment was for 24 months. The main outcome measure was the change in the rate of atrophy of the whole brain assessed by serial volumetric MRI scans. Results A total of 168 participants (85 in active treatment group; 83 receiving placebo) completed the MRI section of the trial. The mean rate of brain atrophy per year was 0.76% [95% CI, 0.63–0.90] in the active treatment group and 1.08% [0.94–1.22] in the placebo group (P = 0.001). The treatment response was related to baseline homocysteine levels: the rate of atrophy in participants with homocysteine >13 µmol/L was 53% lower in the active treatment group (P = 0.001). A greater rate of atrophy was associated with a lower final cognitive test scores. There was no difference in serious adverse events according to treatment category. Conclusions and Significance The accelerated rate of brain atrophy in elderly with mild cognitive impairment can be slowed by treatment with homocysteine-lowering B vitamins. Sixteen percent of those over 70 y old have mild cognitive impairment and half of these develop Alzheimer's disease. Since accelerated brain atrophy is a characteristic of subjects with mild cognitive impairment who convert to Alzheimer's disease, trials are needed to see if the same treatment will delay the development of Alzheimer's disease. Trial Registration Controlled-Trials.com ISRCTN94410159
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Affiliation(s)
- A David Smith
- Oxford Project to Investigate Memory and Ageing, University of Oxford, Oxford, United Kingdom.
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Chen CCV, Tung YY, Chang C. A lifespan MRI evaluation of ventricular enlargement in normal aging mice. Neurobiol Aging 2010; 32:2299-307. [PMID: 20137831 DOI: 10.1016/j.neurobiolaging.2010.01.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Revised: 01/11/2010] [Accepted: 01/18/2010] [Indexed: 10/19/2022]
Abstract
Ventricular enlargement has been proposed as a structural biomarker for the progression of Alzheimer's disease (AD). This biomarker, established in human patients, needs to be translated to animals to facilitate drug development for the disease. However, ventricular enlargement is not exclusive to AD, since the ventricle size increases during normal aging. A longitudinal characterization of ventricular enlargement in normal aging in mice is therefore crucial before further evaluations of mouse models or neurodegenerative diseases associated to brain atrophy. To this end, ventricular enlargement in normal aging mice was characterized over the lifespan (i.e., 2 years). The results showed that the overall ventricle size increased with age, with the expansion beginning during the early life stages and continuing to old age. The reported data represent a biomarker benchmark for normal aging mice under unmodified conditions. This provides a foundation for evaluating the validity of AD mouse models or the effects of potential drugs. The considerable physiological ventricular enlargement during normal aging must be considered in related experiments.
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Affiliation(s)
- Chiao-Chi V Chen
- Institute of Biomedical Sciences, Academic Sinica, Taipei, Taiwan, ROC
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Wischik C, Staff R. Challenges in the conduct of disease-modifying trials in AD: practical experience from a phase 2 trial of Tau-aggregation inhibitor therapy. J Nutr Health Aging 2009; 13:367-9. [PMID: 19300883 DOI: 10.1007/s12603-009-0046-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- C Wischik
- Old Age Psychiatry, Institute of Medical Sciences, Foresterhill, Aberdeen, Scotland, UK.
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Mistur R, Mosconi L, De Santi S, Li Y, Tsui W, de Leon M. Positron emission tomography in Alzheimer’s disease: early prediction and differentiation. FUTURE NEUROLOGY 2009. [DOI: 10.2217/14796708.4.1.23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The development of biomarkers for the preclinical detection of neurodegenerative diseases such as Alzheimer’s disease (AD) is a vital step in developing prevention therapies. One consistent feature of AD is a reduction in the cerebral metabolic rate of glucose (CMRglc), a measure of neuronal function. In vivo brain 2-[18F]fluoro-2-deoxy-D-glucose-PET imaging demonstrates consistent and progressive CMRglc reductions in AD patients, the extent and topography of which correlate with symptom severity. There is increasing evidence that CMRglc reductions occur at the preclinical stages of AD and predict decline years in advance of clinical symptoms. This review will give an overview of FDG-PET results in individuals at risk for developing dementia, including: presymptomatic individuals carrying mutations responsible for early-onset familial AD; patients with mild cognitive impairment, often a prodrome to late-onset sporadic AD; nondemented carriers of the ApoE ε4 allele, a strong genetic risk factor for late-onset AD; cognitively normal subjects with a family history of AD; subjects with subjective memory complaints; and normal elderly who were followed longitudinally until they expressed the clinical symptoms and later received postmortem confirmation of AD. We will then review the most recent studies using FDG-PET as an early differential diagnostic tool in AD.
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Affiliation(s)
- Rachel Mistur
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Lisa Mosconi
- Department of Psychiatry, NYU School of Medicine, 560 First Avenue, New York, NY 10016, USA
| | - Susan De Santi
- Department of Psychiatry, New York University School of Medicine, NY 10016, USA
| | - Yi Li
- Department of Psychiatry, New York University School of Medicine, NY 10016, USA
| | - Wai Tsui
- Department of Psychiatry, New York University School of Medicine, NY 10016, USA and, Nathan Kline Institute, Orangeburg, NY 10962, USA
| | - Mony de Leon
- Department of Psychiatry, New York University School of Medicine, NY 10016, USA and, Nathan Kline Institute, Orangeburg, NY 10962, USA
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Nestor SM, Rupsingh R, Borrie M, Smith M, Accomazzi V, Wells JL, Fogarty J, Bartha R. Ventricular enlargement as a possible measure of Alzheimer's disease progression validated using the Alzheimer's disease neuroimaging initiative database. Brain 2008; 131:2443-54. [PMID: 18669512 DOI: 10.1093/brain/awn146] [Citation(s) in RCA: 308] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Ventricular enlargement may be an objective and sensitive measure of neuropathological change associated with mild cognitive impairment (MCI) and Alzheimer's disease (AD), suitable to assess disease progression for multi-centre studies. This study compared (i) ventricular enlargement after six months in subjects with MCI, AD and normal elderly controls (NEC) in a multi-centre study, (ii) volumetric and cognitive changes between Apolipoprotein E genotypes, (iii) ventricular enlargement in subjects who progressed from MCI to AD, and (iv) sample sizes for multi-centre MCI and AD studies based on measures of ventricular enlargement. Three dimensional T(1)-weighted MRI and cognitive measures were acquired from 504 subjects (NEC n = 152, MCI n = 247 and AD n = 105) participating in the multi-centre Alzheimer's Disease Neuroimaging Initiative. Cerebral ventricular volume was quantified at baseline and after six months using semi-automated software. For the primary analysis of ventricle and neurocognitive measures, between group differences were evaluated using an analysis of covariance, and repeated measures t-tests were used for within group comparisons. For secondary analyses, all groups were dichotomized for Apolipoprotein E genotype based on the presence of an epsilon 4 polymorphism. In addition, the MCI group was dichotomized into those individuals who progressed to a clinical diagnosis of AD, and those subjects that remained stable with MCI after six months. Group differences on neurocognitive and ventricle measures were evaluated by independent t-tests. General sample size calculations were computed for all groups derived from ventricle measurements and neurocognitive scores. The AD group had greater ventricular enlargement compared to both subjects with MCI (P = 0.0004) and NEC (P < 0.0001), and subjects with MCI had a greater rate of ventricular enlargement compared to NEC (P = 0.0001). MCI subjects that progressed to clinical AD after six months had greater ventricular enlargement than stable MCI subjects (P = 0.0270). Ventricular enlargement was different between Apolipoprotein E genotypes within the AD group (P = 0.010). The number of subjects required to demonstrate a 20% change in ventricular enlargement was substantially lower than that required to demonstrate a 20% change in cognitive scores. Ventricular enlargement represents a feasible short-term marker of disease progression in subjects with MCI and subjects with AD for multi-centre studies.
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Affiliation(s)
- Sean M Nestor
- Department of Medical Biophysics, Centre for Functional and Metabolic Mapping, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
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Sluimer JD, van der Flier WM, Karas GB, Fox NC, Scheltens P, Barkhof F, Vrenken H. Whole-brain atrophy rate and cognitive decline: longitudinal MR study of memory clinic patients. Radiology 2008; 248:590-8. [PMID: 18574133 DOI: 10.1148/radiol.2482070938] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To prospectively determine whole-brain atrophy rate in mild cognitive impairment (MCI) and Alzheimer disease (AD) and its association with cognitive decline, and investigate the risk of progression to dementia in initially nondemented patients given baseline brain volume and whole-brain atrophy rate. MATERIALS AND METHODS This study was IRB approved; written informed consent was obtained; and included 65 AD patients (38 women, 27 men; age, 52-81 years), 45 MCI patients (22 women, 23 men; age, 56-80 years), 27 patients with subjective complaints (12 women, 15 men; age, 50-87 years), and 10 healthy controls (six women, four men; age, 53-80 years). Two magnetic resonance (MR) images were acquired at average interval of 1.8 years +/- 0.7 (standard deviation). Baseline brain volume and whole-brain atrophy rates were measured on three-dimensional T1-weighted MR images (1.0 T; single slab, 168 sections; matrix size, 256 x 256; field of view, 250 mm; voxel size, 1 x 1 x 1.5 mm; repetition time msec/echo time msec/inversion time msec, 15/7/300; and flip angle, 15 degrees ). Associations were assessed by using partial-correlations. Cox proportional hazards models were used to estimate risk of developing dementia. RESULTS Baseline brain volume was lowest in AD but did not differ significantly between MCI, subjective complaints, and control groups (P > .38). Whole-brain atrophy rates were higher in AD (-1.9% per year +/- 0.9) than MCI (-1.2% per year +/- 0.9, P = .003) patients, who had higher whole-brain atrophy rates than patients with subjective complaints (-0.7% per year +/- 0.7, P = .03) and controls (-0.5% per year +/- 0.5, P = .05). Whole-brain atrophy rate correlated with annualized Mini-Mental State Examination (MMSE) change (r = 0.48, P < .001), while baseline volume did not (r = 0.11, P = .22). Cox models showed that-after correction for age, sex, and baseline MMSE-a higher whole-brain atrophy rate was associated with an increased risk of progression to dementia (highest vs lowest tertile [hazard ratio, 3.6; 95% confidence interval: 1.2, 11.4]). CONCLUSION Whole-brain atrophy rate was strongly associated with cognitive decline. In nondemented participants, a high whole-brain atrophy rate was associated with an increased risk of progression to dementia.
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Affiliation(s)
- Jasper D Sluimer
- Department of Diagnostic Radiology, Alzheimer Centre, Vrije Universiteit Medical Centre, Amsterdam, the Netherlands.
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Heckemann RA, Hammers A, Rueckert D, Aviv RI, Harvey CJ, Hajnal JV. Automatic volumetry on MR brain images can support diagnostic decision making. BMC Med Imaging 2008; 8:9. [PMID: 18500985 PMCID: PMC2413211 DOI: 10.1186/1471-2342-8-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Accepted: 05/23/2008] [Indexed: 01/09/2023] Open
Abstract
Background Diagnostic decisions in clinical imaging currently rely almost exclusively on visual image interpretation. This can lead to uncertainty, for example in dementia disease, where some of the changes resemble those of normal ageing. We hypothesized that extracting volumetric data from patients' MR brain images, relating them to reference data and presenting the results as a colour overlay on the grey scale data would aid diagnostic readers in classifying dementia disease versus normal ageing. Methods A proof-of-concept forced-choice reader study was designed using MR brain images from 36 subjects. Images were segmented into 43 regions using an automatic atlas registration-based label propagation procedure. Seven subjects had clinically probable AD, the remaining 29 of a similar age range were used as controls. Seven of the control subject data sets were selected at random to be presented along with the seven AD datasets to two readers, who were blinded to all clinical and demographic information except age and gender. Readers were asked to review the grey scale MR images and to record their choice of diagnosis (AD or non-AD) along with their confidence in this decision. Afterwards, readers were given the option to switch on a false-colour overlay representing the relative size of the segmented structures. Colorization was based on the size rank of the test subject when compared with a reference group consisting of the 22 control subjects who were not used as review subjects. The readers were then asked to record whether and how the additional information had an impact on their diagnostic confidence. Results The size rank colour overlays were useful in 18 of 28 diagnoses, as determined by their impact on readers' diagnostic confidence. A not useful result was found in 6 of 28 cases. The impact of the additional information on diagnostic confidence was significant (p < 0.02). Conclusion Volumetric anatomical information extracted from brain images using automatic segmentation and presented as colour overlays can support diagnostic decision making.
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Affiliation(s)
- Rolf A Heckemann
- Division of Neurosciences and Mental Health, Imperial College London, Hammersmith Campus, Du Cane Road, London, UK.
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Barnes J, Foster J, Fox NC. Structural magnetic resonance imaging-derived biomarkers for Alzheimer’s disease. Biomark Med 2007; 1:79-92. [DOI: 10.2217/17520363.1.1.79] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The development and validation of biomarkers for prediction, diagnosis and tracking of progression of Alzheimer’s disease are both increasingly important. As potential pharmaceutical agents are developed for Alzheimer’s disease, their efficacy needs to be assessed. When medications become available, those subjects who may derive most benefit from such treatments need to be selected and their response to treatment monitored. As such, there has been much research into biomarkers in recent years, with many showing promise in all areas of biomarker utility. This review focuses on the potential of structural imaging as a biomarker in Alzheimer’s disease.
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Affiliation(s)
- Josephine Barnes
- Dementia Research Centre, University College London, Box 16, The National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, UK
| | - Jo Foster
- Dementia Research Centre, University College London, Box 16, The National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, UK
| | - Nick C Fox
- Dementia Research Centre, University College London, Box 16, The National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, UK
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Carmichael OT, Kuller LH, Lopez OL, Thompson PM, Dutton RA, Lu A, Lee SE, Lee JY, Aizenstein HJ, Meltzer CC, Liu Y, Toga AW, Becker JT. Cerebral ventricular changes associated with transitions between normal cognitive function, mild cognitive impairment, and dementia. Alzheimer Dis Assoc Disord 2007; 21:14-24. [PMID: 17334268 PMCID: PMC2879163 DOI: 10.1097/wad.0b013e318032d2b1] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Expansion of the cerebral ventricles may occur at an accelerated rate in subjects with dementia, but the time course of expansion during transitions between normal cognitive function, mild cognitive impairment (MCI), and dementia is not well understood. Furthermore, the effects of cardiovascular risk factors on rate of ventricular expansion are unclear. We used a fully automated segmentation technique to measure change rate in lateral ventricle-to-brain ratio (VBR) on 145 longitudinal pairs of magnetic resonance images of subjects in the Cardiovascular Health Study Cognition Study from the Pittsburgh Center. A multivariate model analyzed VBR change rate, accounting for dementia statuses at both imaging times (normal, MCI, or dementia), age, sex, education, race, magnetic resonance-defined infarcts, Center for Epidemiology Studies Depression Scale, baseline ventricular volume, and cardiovascular risk factors. VBR change was faster in subjects who were demented or transitioned from MCI to dementia, compared with subjects normal at both images and subjects who transitioned from normal to MCI or dementia. Patients with diabetes had faster VBR change. Ventricular expansion may accelerate late in the progression from normal cognitive function to dementia, and may be modulated by diabetes.
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Affiliation(s)
- Owen T Carmichael
- Neurology and Computer Science Departments, Center for Neuroscience, University of California-Davis, 1544 Newton Court, Davis, CA 95616, USA.
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Barnes J, Scahill RI, Frost C, Schott JM, Rossor MN, Fox NC. Increased hippocampal atrophy rates in AD over 6 months using serial MR imaging. Neurobiol Aging 2007; 29:1199-203. [PMID: 17368654 DOI: 10.1016/j.neurobiolaging.2007.02.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 01/15/2007] [Accepted: 02/05/2007] [Indexed: 11/26/2022]
Abstract
We measured hippocampi on baseline-, 6- and 12-month scans in a group of AD (n=36) and control subjects (n=20). We found that mean annualised atrophy rates using 6-month intervals were comparable at a group level to those generated from a 12-month interval. Higher variance was seen using shorter intervals, although this was only significant in the control group. This has implications where shorter inter-scan intervals may be advantageous, such as rapid diagnosis, and tracking of disease progression including in a clinical trial.
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Affiliation(s)
- J Barnes
- Dementia Research Centre, UCL, Institute of Neurology, London, United Kingdom.
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Mueller SG, Schuff N, Weiner MW. Evaluation of treatment effects in Alzheimer's and other neurodegenerative diseases by MRI and MRS. NMR IN BIOMEDICINE 2006; 19:655-68. [PMID: 16986115 PMCID: PMC1820857 DOI: 10.1002/nbm.1062] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Neurodegeneration refers to a large clinically and pathologically heterogeneous disease entity associated with slowly progressive neuronal loss in different anatomical and functional systems of the brain. Neurodegenerative diseases often affect cognition, e.g. Alzheimer's disease (AD), dementia with Lewy bodies and vascular dementia, or different aspects of the motor system, e.g., amyotrophic lateral sclerosis, Parkinson's disease and ataxic disorders. Owing to increasing knowledge about the mechanisms leading to neurodegeneration, the development of treatments able to modify the neurodegenerative process becomes possible for the first time. Currently, clinical outcome measures are used to assess the efficacy of such treatments. However, most clinical outcome measures have a low test-retest reliability and thus considerable measurement variance. Therefore, large patient populations and long observation times are needed to detect treatment effects. Furthermore, clinical outcome measures cannot distinguish between symptomatic and disease-modifying treatment effects. Therefore, alternative biomarkers including neuroimaging may take on a more important role in this process. Because MR scanners are widely available and allow for non-invasive detection and quantification of changes in brain structure and metabolism, there is increasing interest in the use of MRI/MRS to monitor objectively treatment effects in clinical trials of neurodegenerative diseases. Particularly volumetric MRI has been used to measure atrophy rates in treatment trials of AD because the relationship between atrophic changes and neuron loss is well established and correlates well with clinical measures. More research is needed to determine the value of other MR modalities, i.e. diffusion, perfusion and functional MRI and MR spectroscopy, for clinical trials with neuroprotective drugs.
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Affiliation(s)
- S. G. Mueller
- Center of Imaging of Neurodegenerative Diseases, Veterans Administration Medical Center, Department of Radiology, University of California San Francisco, San Francisco, CA 94121, USA
| | - N. Schuff
- Center of Imaging of Neurodegenerative Diseases, Veterans Administration Medical Center, Department of Radiology, University of California San Francisco, San Francisco, CA 94121, USA
| | - M. W. Weiner
- Center of Imaging of Neurodegenerative Diseases, Veterans Administration Medical Center, Department of Radiology, University of California San Francisco, San Francisco, CA 94121, USA
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30
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Schott JM, Frost C, Whitwell JL, Macmanus DG, Boyes RG, Rossor MN, Fox NC. Combining short interval MRI in Alzheimer's disease: Implications for therapeutic trials. J Neurol 2006; 253:1147-53. [PMID: 16998650 DOI: 10.1007/s00415-006-0173-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Revised: 11/16/2005] [Accepted: 11/30/2005] [Indexed: 11/24/2022]
Abstract
Cerebral atrophy calculated from serial MRI is a marker of Alzheimer's disease (AD) progression, and a potential outcome measure for therapeutic trials. Reducing within-subject variability in cerebral atrophy rates by acquiring more than two serial scans could allow for shorter clinical trials requiring smaller patient numbers. Forty-six patients with AD and 23 controls each had up to 10 serial MR brain scans over two years. Whole brain atrophy was calculated for each subject from every scan-pair. 708 volumetric MRI scans were acquired: 2199 measures of atrophy were made for patients, and 1182 for controls. A linear mixed model was used to characterise between and within-individual variability. These results were used to investigate the power of combining multiple serial scans in treatment trials of varying lengths. In AD, the mean whole brain atrophy rate was 2.23%/year (95% CI: 1.90-2.56%/year). The linear mixed model was shown to fit the data well and led to a formula (0.99(2) + (0.82/t)2) for the variance of atrophy rates calculated from two scans "t" years apart. Utilising five optimally timed scans with repeat scans at each visit reduced the component of atrophy rate variance attributable to within-subject variability by approximately 56%, equating to a approximately 40% sample size reduction (228 vs 387 patients per arm to detect 20% reduction in atrophy rate) in a six-month placebo-controlled trial. This benefit in terms of sample size is relatively reduced in longer trials, although adding extra scanning visits may have benefits when patient drop-outs are accounted for. We conclude that sample sizes required in short interval therapeutic trials using cerebral atrophy as an outcome measure may be reduced if multiple serial MRI is performed.
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Affiliation(s)
- J M Schott
- Dementia Research Centre, Institute of Neurology, University College London, Queen Square, Box 16, WC1N 3BG, London, UK
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31
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Boyes RG, Rueckert D, Aljabar P, Whitwell J, Schott JM, Hill DLG, Fox NC. Cerebral atrophy measurements using Jacobian integration: Comparison with the boundary shift integral. Neuroimage 2006; 32:159-69. [PMID: 16675272 DOI: 10.1016/j.neuroimage.2006.02.052] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Revised: 01/26/2006] [Accepted: 02/27/2006] [Indexed: 11/21/2022] Open
Abstract
We compared two methods of measuring cerebral atrophy in a cohort of 38 clinically probable Alzheimer's disease (AD) subjects and 22 age-matched normal controls, using metrics of zero atrophy, consistency, scaled atrophy and AD/control group separation. The two methods compared were the boundary shift integral (BSI) and a technique based on the integration of Jacobian determinants from non-rigid registration. For each subject, we used two volumetric magnetic resonance (MR) scans at baseline and a third obtained 1 year later. The case of zero atrophy was established by registering the same-day baseline scan pair, which should approximate zero change. Consistency was established by registering the 1-year follow-up scan to each of the baseline scans, giving two measurements of atrophy that should be very similar, while scaled atrophy was established by reducing one of the same-day scans by a fixed amount, and rigidly registering this to the other same-day scan. Group separation was ascertained by calculating atrophy rates over the two 1-year measures for the control and AD subjects. The results showed the Jacobian integration technique was significantly more accurate in calculating scaled atrophy (P < 0.001) and was able to distinguish between control and AD subjects more clearly (P < 0.01).
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Affiliation(s)
- Richard G Boyes
- Dementia Research Centre, Institute of Neurology, Box 16, University College London, Queen Square, London WC1N 3BG, UK.
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32
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Acceleration of cerebral ventricular expansion in the Cardiovascular Health Study. Neurobiol Aging 2006; 28:1316-21. [PMID: 16875759 DOI: 10.1016/j.neurobiolaging.2006.06.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 06/14/2006] [Accepted: 06/19/2006] [Indexed: 02/05/2023]
Abstract
Interactions between prevalent late-life medical conditions and expansion of the cerebral ventricles are not well understood. Thirty elderly subjects received three magnetic resonance (MR) scans each, in 1997-1999, 2002-2004, and 2003-2005. A linear expansion model of MR-measured lateral ventricle volume was estimated for each subject by fitting a line to a plot of their 1997-1999 and 2002-2004 volumes as a function of time. Acceleration in ventricular expansion was defined as the deviation between the 2003-2005 volumes measured from MR and the 2003-2005 volumes predicted by the linear expansion model. Ventricular acceleration was analyzed in a multivariate model with age, race, history of heart disease, diabetes, and hypertension as fixed effects. Ventricular acceleration was significantly higher in non-whites, diabetics, and those without heart disease (p<0.05). Ventricular acceleration was higher in subjects with a history of hypertension, but the difference was not statistically significant (p=0.08). Acceleration of ventricular expansion in the elderly may be related to demographic and cardiovascular factors.
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Thal LJ, Kantarci K, Reiman EM, Klunk WE, Weiner MW, Zetterberg H, Galasko D, Praticò D, Griffin S, Schenk D, Siemers E. The role of biomarkers in clinical trials for Alzheimer disease. Alzheimer Dis Assoc Disord 2006; 20:6-15. [PMID: 16493230 PMCID: PMC1820855 DOI: 10.1097/01.wad.0000191420.61260.a8] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Biomarkers are likely to be important in the study of Alzheimer disease (AD) for a variety of reasons. A clinical diagnosis of Alzheimer disease is inaccurate even among experienced investigators in about 10% to 15% of cases, and biomarkers might improve the accuracy of diagnosis. Importantly for the development of putative disease-modifying drugs for Alzheimer disease, biomarkers might also serve as indirect measures of disease severity. When used in this way, sample sizes of clinical trials might be reduced, and a change in biomarker could be considered supporting evidence of disease modification. This review summarizes a meeting of the Alzheimer's Association's Research Roundtable, during which existing and emerging biomarkers for AD were evaluated. Imaging biomarkers including volumetric magnetic resonance imaging and positron emission tomography assessing either glucose utilization or ligands binding to amyloid plaque are discussed. Additionally, biochemical biomarkers in blood or cerebrospinal fluid are assessed. Currently appropriate uses of biomarkers in the study of Alzheimer disease, and areas where additional work is needed, are discussed.
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Affiliation(s)
- Leon J. Thal
- From the University of California San Diego, Department of Neurosciences, La Jolla, California
| | - Kejal Kantarci
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | - Eric M. Reiman
- Banner Good Samaritan Medical Center, University of Arizona, Translational Genomics Research Institute, Arizona Alzheimer’s Disease Consortium, Phoenix, Arizona
| | - William E. Klunk
- Department of Psychiatry, Laboratory of Molecular Neuropharmacology, Western Psychiatric Institute and Clinic, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Michael W. Weiner
- Center for Imaging of Neurodegenerative Diseases, VA Medical Center
- Department of Radiology, University of California, San Francisco; San Francisco, California; # Center for Neurologic Diseases, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Henrik Zetterberg
- From the University of California San Diego, Department of Neurosciences, La Jolla, California
- Institute of Clinical Neuroscience, Department of Experimental Neuroscience, Sahlgrenska University Hospital, Göteborg University, Göteborg, Sweden
| | - Douglas Galasko
- Department of Neurosciences, University of California, San Diego; San Diego, California
| | - Domenico Praticò
- Department of Pharmacology, Center for Experimental Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Sue Griffin
- Donald W. Reynolds Institute on Aging, Department of Geriatrics, University of Arkansas for Medical Sciences and GRECC VA Medical Center, Little Rock, Arkansas
| | - Dale Schenk
- Elan Pharmaceuticals, South San Francisco, California
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Preboske GM, Gunter JL, Ward CP, Jack CR. Common MRI acquisition non-idealities significantly impact the output of the boundary shift integral method of measuring brain atrophy on serial MRI. Neuroimage 2005; 30:1196-202. [PMID: 16380273 PMCID: PMC2751846 DOI: 10.1016/j.neuroimage.2005.10.049] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Revised: 10/18/2005] [Accepted: 10/31/2005] [Indexed: 11/15/2022] Open
Abstract
Measuring rates of brain atrophy from serial magnetic resonance imaging (MRI) studies is an attractive way to assess disease progression in neurodegenerative disorders, particularly Alzheimer's disease (AD). A widely recognized approach is the boundary shift integral (BSI). The objective of this study was to evaluate how several common scan non-idealities affect the output of the BSI algorithm. We created three types of image non-idealities between the image volumes in a serial pair used to measure between-scan change: inconsistent image contrast between serial scans, head motion, and poor signal-to-noise (SNR). In theory the BSI volume difference measured between each pair of images should be zero and any deviation from zero should represent corruption of the BSI measurement by some non-ideality intentionally introduced into the second scan in the pair. Two different BSI measures were evaluated, whole brain and ventricle. As the severity of motion, noise, and non-congruent image contrast increased in the second scan, the calculated BSI values deviated progressively more from the expected value of zero. This study illustrates the magnitude of the error in measures of change in brain and ventricle volume across serial MRI scans that can result from commonly encountered deviations from ideal image quality. The magnitudes of some of the measurement errors seen in this study exceed the disease effect in AD shown in various publications, which range from 1% to 2.78% per year for whole brain atrophy and 5.4% to 13.8% per year for ventricle expansion (Table 1). For example, measurement error may exceed 100% if image contrast properties dramatically differ between the two scans in a measurement pair. Methods to maximize consistency of image quality over time are an essential component of any quantitative serial MRI study.
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Affiliation(s)
- Gregory M Preboske
- Mayo Clinic and Foundation, Department of Radiology, 200 First Street SW, Rochester, MN 55905, USA
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35
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Dickerson BC, Sperling RA. Neuroimaging biomarkers for clinical trials of disease-modifying therapies in Alzheimer's disease. NeuroRx 2005; 2:348-60. [PMID: 15897955 PMCID: PMC1064996 DOI: 10.1602/neurorx.2.2.348] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The pathophysiologic process leading to neurodegeneration in Alzheimer's disease (AD) is thought to begin long before clinical symptoms develop. Existing therapeutics for AD improve symptoms, but increasing efforts are being directed toward the development of therapies to impede the pathologic progression of the disease. Although these medications must ultimately demonstrate efficacy in slowing clinical decline, there is a critical need for biomarkers that will indicate whether a candidate disease-modifying therapeutic agent is actually altering the underlying degenerative process. A number of in vivo neuroimaging techniques, which can reliably and noninvasively assess aspects of neuroanatomy, chemistry, physiology, and pathology, hold promise as biomarkers. These neuroimaging measures appear to relate closely to neuropathological and clinical data, such as rate of cognitive decline and risk of future decline. As this work has matured, it has become clear that neuroimaging measures may serve a variety of potential roles in clinical trials of candidate neurotherapeutic agents for AD, depending in part on the question of interest and phase of drug development. In this article, we review data related to the range of neuroimaging biomarkers of Alzheimer's disease and consider potential applications of these techniques to clinical trials, particularly with respect to the monitoring of disease progression in trials of disease-modifying therapies.
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Affiliation(s)
- Bradford C Dickerson
- Department of Neurology and the Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA.
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Thompson PM, Hayashi KM, De Zubicaray GI, Janke AL, Rose SE, Semple J, Hong MS, Herman DH, Gravano D, Doddrell DM, Toga AW. Mapping hippocampal and ventricular change in Alzheimer disease. Neuroimage 2004; 22:1754-66. [PMID: 15275931 DOI: 10.1016/j.neuroimage.2004.03.040] [Citation(s) in RCA: 422] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2004] [Revised: 03/25/2004] [Accepted: 03/30/2004] [Indexed: 10/26/2022] Open
Abstract
We developed an anatomical mapping technique to detect hippocampal and ventricular changes in Alzheimer disease (AD). The resulting maps are sensitive to longitudinal changes in brain structure as the disease progresses. An anatomical surface modeling approach was combined with surface-based statistics to visualize the region and rate of atrophy in serial MRI scans and isolate where these changes link with cognitive decline. Sixty-two [corrected] high-resolution MRI scans were acquired from 12 AD patients (mean [corrected] age +/- SE at first scan: 68.7 +/- 1.7 [corrected] years) and 14 matched controls (age: 71.4 +/- 0.9 years) [corrected] each scanned twice (1.9 +/- 0.2 [corrected] years apart, when all subjects are pooled [corrected] 3D parametric mesh models of the hippocampus and temporal horns were created in sequential scans and averaged across subjects to identify systematic patterns of atrophy. As an index of radial atrophy, 3D distance fields were generated relating each anatomical surface point to a medial curve threading down the medial axis of each structure. Hippocampal atrophic rates and ventricular expansion were assessed statistically using surface-based permutation testing and were faster in AD than in controls. Using color-coded maps and video sequences, these changes were visualized as they progressed anatomically over time. Additional maps localized regions where atrophic changes linked with cognitive decline. Temporal horn expansion maps were more sensitive to AD progression than maps of hippocampal atrophy, but both maps correlated with clinical deterioration. These quantitative, dynamic visualizations of hippocampal atrophy and ventricular expansion rates in aging and AD may provide a promising measure to track AD progression in drug trials.
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Affiliation(s)
- Paul M Thompson
- Laboratory of Neuro Imaging, Brain Mapping Division, Department of Neurology, UCLA School of Medicine, Los Angeles, CA 90095, USA.
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37
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Abstract
Recent advances in understanding the molecular biology of Alzheimer's disease (AD) offer the promise of useful therapeutic intervention in the foreseeable future. Hence, improved methods for early diagnosis and noninvasive surrogates of disease severity in AD have become more imperative. Various quantitative magnetic resonance (MR) techniques that measure the anatomic, biochemical, microstructural, functional, and blood-flow changes are being evaluated as possible surrogate measures of disease progression. Cross-sectional and longitudinal studies indicate that MR-based volume measurements are potential surrogates of disease progression in AD, starting from the preclinical stages. The validity of MR-based volumetry as a surrogate marker for therapeutic efficacy in AD remains to be tested in a positive disease-modifying drug trial. Recent development of amyloid imaging tracers for positron emission tomography has been a major breakthrough in the field of imaging markers for AD. Efforts to image plaques are also underway in MR imaging. As with indirect MR measures, these approaches of directly imaging the pathological substrate will need to undergo a validation process with longitudinal studies to prove their usefulness as surrogate markers in AD.
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Affiliation(s)
- Kejal Kantarci
- Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905, USA.
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