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Near-Lifespan Tracking of Cerebral Microvascular Degeneration in Aging to Alzheimer’s Continuum. ADVANCES IN GERIATRIC MEDICINE AND RESEARCH 2022; 4. [PMID: 35466329 PMCID: PMC9022674 DOI: 10.20900/agmr20220003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder affecting millions of people worldwide and is currently incurable. As the population ages, AD and related dementia are becoming the biggest epidemic in medical history: the number of people aged 65 and older with AD is projected to increase between two- and three-fold by 2050. Imaging and biomarker studies suggest that the pathophysiological processes of AD begin more than a decade before the diagnosis of dementia, opening the possibility of early, preemptive prediction. For accurate prediction, it is important although challenging to fully understand how multiple etiologies and age-related prodromal processes contribute to the onset of Alzheimer’s continuum, across a long period comparable to the lifespan. Addressing this challenge was one of the overarching transformative concepts at the 2015 AD Research Summit, “to develop new programs on systems biology and integrative physiology to gain a deeper understanding of the complex biology of the disease.” Among other factors, cerebral microvascular degeneration (CMD) may play a key role in the onset and development of Alzheimer’s continuum, potentially prior to, along with, or independently of the beta-amyloid (Aβ) accumulation. Despite its importance for early detection and as a therapeutic target for early intervention, it is unknown whether CMD is a causal factor for AD pathogenesis or an early consequence of multifactorial conditions that lead to AD at a later stage. Here, this Viewpoint suggests that we should fill two critical knowledge gaps: (1) Temporal relationships between various CMDs and other key factors before/during/after the onset of Alzheimer’s continuum have not been established; (2) Little integrative study down to the capillary vessel level has been conducted on how individual defects in various microvascular structural and flow properties distinctly correlate with and/or contribute to neuronal degeneration. As the first step toward filling these gaps, I propose utilizing recent advances in microscopic imaging and image analysis techniques to longitudinally track a comprehensive set of CMDs over the lifespan in model animals, along with Aβ, tau, neuronal degeneration, and cognitive impairment when possible.
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Imai M, Tanaka M, Sakata M, Wagatsuma K, Tago T, Toyohara J, Sengoku R, Nishina Y, Kanemaru K, Ishibashi K, Murayama S, Ishii K. Metabolic Network Topology of Alzheimer's Disease and Dementia with Lewy Bodies Generated Using Fluorodeoxyglucose Positron Emission Tomography. J Alzheimers Dis 2021; 73:197-207. [PMID: 31771066 PMCID: PMC7029362 DOI: 10.3233/jad-190843] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Background: Alzheimer’s disease (AD) and dementia with Lewy bodies (DLB) are often misdiagnosed with each other because of similar symptoms including progressive memory loss. The metabolic network topology that describes inter-regional metabolic connections can be generated using fluorodeoxyglucose positron emission tomography (FDG-PET) data with the graph-theoretical method. We hypothesized that different metabolic connectivity underlies the symptoms of AD patients, DLB patients, and cognitively normal (CN) individuals. Objective: This study aimed to generate metabolic connectivity using FDG-PET data and assess the network topology to differentiate AD patients, DLB patients, and CN individuals. Methods: This study included 45 AD patients, 18 DLB patients, and 142 CN controls. We analyzed FDG-PET data using the graph-theoretical method and generated the network topology in AD patients, DLB patients, and CN individuals. We statistically assessed the topology with global and nodal parameters. Results: The whole metabolic network was preserved in CN; however, diffusely decreased connection was found in AD and partially but more deeply decreased connection was observed in DLB. The metabolic topology revealed that the right posterior cingulate and the left transverse temporal gyrus were significantly different between AD and DLB. Conclusion: The present findings indicate that metabolic connectivity decreased in both AD and DLB, compared with CN. DLB was characterized restricted but deeper stereotyped network disruption compared with AD. The right posterior cingulate and the left transverse temporal gyrus are significant regions in the metabolic connectivity for differentiating AD from DLB.
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Affiliation(s)
- Masamichi Imai
- Team for Neuroimaging Research, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.,Toranomon Hospital, Tokyo, Japan
| | - Mika Tanaka
- Team for Neuroimaging Research, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Muneyuki Sakata
- Team for Neuroimaging Research, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Kei Wagatsuma
- Team for Neuroimaging Research, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Tetsuro Tago
- Team for Neuroimaging Research, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Jun Toyohara
- Team for Neuroimaging Research, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Renpei Sengoku
- Department of Neurology, Tokyo Metropolitan Geriatric Hosptal and Institute of Gerontology, Tokyo, Japan
| | - Yuji Nishina
- Department of Neurology, Tokyo Metropolitan Geriatric Hosptal and Institute of Gerontology, Tokyo, Japan
| | - Kazutomi Kanemaru
- Department of Neurology, Tokyo Metropolitan Geriatric Hosptal and Institute of Gerontology, Tokyo, Japan
| | - Kenji Ishibashi
- Team for Neuroimaging Research, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Shigeo Murayama
- Department of Neurology, Tokyo Metropolitan Geriatric Hosptal and Institute of Gerontology, Tokyo, Japan
| | - Kenji Ishii
- Team for Neuroimaging Research, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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Bell SM, De Marco M, Barnes K, Shaw PJ, Ferraiuolo L, Blackburn DJ, Mortiboys H, Venneri A. Deficits in Mitochondrial Spare Respiratory Capacity Contribute to the Neuropsychological Changes of Alzheimer's Disease. J Pers Med 2020; 10:jpm10020032. [PMID: 32365522 PMCID: PMC7354560 DOI: 10.3390/jpm10020032] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/20/2020] [Accepted: 04/24/2020] [Indexed: 12/20/2022] Open
Abstract
Alzheimer’s disease (AD) is diagnosed using neuropsychological testing, supported by amyloid and tau biomarkers and neuroimaging abnormalities. The cause of neuropsychological changes is not clear since they do not correlate with biomarkers. This study investigated if changes in cellular metabolism in AD correlate with neuropsychological changes. Fibroblasts were taken from 10 AD patients and 10 controls. Metabolic assessment included measuring total cellular ATP, extracellular lactate, mitochondrial membrane potential (MMP), mitochondrial respiration and glycolytic function. All participants were assessed with neuropsychological testing and brain structural MRI. AD patients had significantly lower scores in delayed and immediate recall, semantic memory, phonemic fluency and Mini Mental State Examination (MMSE). AD patients also had significantly smaller left hippocampal, left parietal, right parietal and anterior medial prefrontal cortical grey matter volumes. Fibroblast MMP, mitochondrial spare respiratory capacity (MSRC), glycolytic reserve, and extracellular lactate were found to be lower in AD patients. MSRC/MMP correlated significantly with semantic memory, immediate and delayed episodic recall. Correlations between MSRC and delayed episodic recall remained significant after controlling for age, education and brain reserve. Grey matter volumes did not correlate with MRSC/MMP. AD fibroblast metabolic assessment may represent an emergent disease biomarker of AD.
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Affiliation(s)
| | | | | | | | | | | | - Heather Mortiboys
- Correspondence: (H.M.); (A.V.); Tel.: +44-(0)114-222-2259 (H.M.); +44-(0)114-271-3430 (A.V.)
| | - Annalena Venneri
- Correspondence: (H.M.); (A.V.); Tel.: +44-(0)114-222-2259 (H.M.); +44-(0)114-271-3430 (A.V.)
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Okazawa H, Ikawa M, Jung M, Maruyama R, Tsujikawa T, Mori T, Rahman MGM, Makino A, Kiyono Y, Kosaka H. Multimodal analysis using [ 11C]PiB-PET/MRI for functional evaluation of patients with Alzheimer's disease. EJNMMI Res 2020; 10:30. [PMID: 32232573 PMCID: PMC7105527 DOI: 10.1186/s13550-020-00619-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/19/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Multimodal PET/MRI image data simultaneously obtained from patients with early-stage of Alzheimer's disease (eAD) were assessed in order to observe pathophysiologic and functional changes, as well as alterations of morphology and connectivity in the brain. Fifty-eight patients with mild cognitive impairment and early dementia (29 males, 69 ± 12 years) underwent [11C]Pittsburgh compound-B (PiB) PET/MRI with 70-min PET and MRI scans. Sixteen age-matched healthy controls (CTL) (9 males, 68 ± 11 years) were also studied with the same scanning protocol. Cerebral blood flow (CBF) was calculated from the early phase PET images using the image-derived input function method. A standardized uptake value ratio (SUVr) was calculated from 50 to 70 min PET data with a reference region of the cerebellar cortex. MR images such as 3D-T1WI, resting-state functional MRI (RS-fMRI), diffusion tensor image (DTI), and perfusion MRI acquired during the dynamic PET scan were also analyzed to evaluate various brain functions on MRI. RESULTS Twenty-seven of the 58 patients were determined as eAD based on the results of PiB-PET and clinical findings, and a total of 43 subjects' data including CTL were analyzed in this study. PiB SUVr values in all cortical regions of eAD were significantly greater than those of CTL. The PiB accumulation intensity was negatively correlated with cognitive scores. The regional PET-CBF values of eAD were significantly lower in the bilateral parietal lobes and right temporal lobe compared with CTL, but not in MRI perfusion; however, SPM showed regional differences on both PET- and MRI-CBF. SPM analysis of RS-fMRI delineated regional differences between the groups in the anterior cingulate cortex and the left precuneus. VBM analysis showed atrophic changes in the AD group in a part of the bilateral hippocampus; however, analysis of fractional anisotropy calculated from DTI data did not show differences between the two groups. CONCLUSION Multimodal analysis conducted with various image data from PiB-PET/MRI scans showed differences in regional CBF, cortical volume, and neuronal networks in different regions, indicating that pathophysiologic and functional changes in the AD brain can be observed from various aspects of neurophysiologic parameters. Application of multimodal brain images using PET/MRI would be ideal for investigating pathophysiologic changes in patients with dementia and other neurodegenerative diseases.
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Affiliation(s)
- Hidehiko Okazawa
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan.
| | - Masamichi Ikawa
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan.,Department of Neurology, Faculty of Medical Sciences, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
| | - Minyoung Jung
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan.,Department of Psychiatry, Faculty of Medical Sciences, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
| | - Rikiya Maruyama
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
| | - Tetsuya Tsujikawa
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
| | - Tetsuya Mori
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
| | - Mahmudur G M Rahman
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan.,Department of Biomedical Engineering, Khulna University of Engineering & Technology, Khulna, 9203, Bangladesh
| | - Akira Makino
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
| | - Yasushi Kiyono
- Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
| | - Hirotaka Kosaka
- Department of Psychiatry, Faculty of Medical Sciences, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan
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Govindpani K, McNamara LG, Smith NR, Vinnakota C, Waldvogel HJ, Faull RL, Kwakowsky A. Vascular Dysfunction in Alzheimer's Disease: A Prelude to the Pathological Process or a Consequence of It? J Clin Med 2019; 8:E651. [PMID: 31083442 PMCID: PMC6571853 DOI: 10.3390/jcm8050651] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 04/29/2019] [Accepted: 05/06/2019] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia. Despite decades of research following several theoretical and clinical lines, all existing treatments for the disorder are purely symptomatic. AD research has traditionally been focused on neuronal and glial dysfunction. Although there is a wealth of evidence pointing to a significant vascular component in the disease, this angle has been relatively poorly explored. In this review, we consider the various aspects of vascular dysfunction in AD, which has a significant impact on brain metabolism and homeostasis and the clearance of β-amyloid and other toxic metabolites. This may potentially precede the onset of the hallmark pathophysiological and cognitive symptoms of the disease. Pathological changes in vessel haemodynamics, angiogenesis, vascular cell function, vascular coverage, blood-brain barrier permeability and immune cell migration may be related to amyloid toxicity, oxidative stress and apolipoprotein E (APOE) genotype. These vascular deficits may in turn contribute to parenchymal amyloid deposition, neurotoxicity, glial activation and metabolic dysfunction in multiple cell types. A vicious feedback cycle ensues, with progressively worsening neuronal and vascular pathology through the course of the disease. Thus, a better appreciation for the importance of vascular dysfunction in AD may open new avenues for research and therapy.
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Affiliation(s)
- Karan Govindpani
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Laura G McNamara
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Nicholas R Smith
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Chitra Vinnakota
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Henry J Waldvogel
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Richard Lm Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Andrea Kwakowsky
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
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6
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Mao N, Liu Y, Chen K, Yao L, Wu X. Combinations of Multiple Neuroimaging Markers using Logistic Regression for Auxiliary Diagnosis of Alzheimer Disease and Mild Cognitive Impairment. NEURODEGENER DIS 2018; 18:91-106. [DOI: 10.1159/000487801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 02/16/2018] [Indexed: 11/19/2022] Open
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Leuzy A, Rodriguez-Vieitez E, Saint-Aubert L, Chiotis K, Almkvist O, Savitcheva I, Jonasson M, Lubberink M, Wall A, Antoni G, Nordberg A. Longitudinal uncoupling of cerebral perfusion, glucose metabolism, and tau deposition in Alzheimer's disease. Alzheimers Dement 2017; 14:652-663. [PMID: 29268078 DOI: 10.1016/j.jalz.2017.11.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Revised: 11/14/2017] [Accepted: 11/16/2017] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Cross-sectional findings using the tau tracer [18F]THK5317 (THK5317) have shown that [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) data can be approximated using perfusion measures (early-frame standardized uptake value ratio; ratio of tracer delivery in target to reference regions). In this way, a single PET study can provide both functional and molecular information. METHODS We included 16 patients with Alzheimer's disease who completed follow-up THK5317 and FDG studies 17 months after baseline investigations. Linear mixed-effects models and annual percentage change maps were used to examine longitudinal change. RESULTS Limited spatial overlap was observed between areas showing declines in THK5317 perfusion measures and FDG. Minimal overlap was seen between areas showing functional change and those showing increased retention of THK5317. DISCUSSION Our findings suggest a spatiotemporal offset between functional changes and tau pathology and a partial uncoupling between perfusion and metabolism, possibly as a function of Alzheimer's disease severity.
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Affiliation(s)
- Antoine Leuzy
- Division of Translational Alzheimer Neurobiology, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Stockholm, Sweden
| | - Elena Rodriguez-Vieitez
- Division of Translational Alzheimer Neurobiology, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Stockholm, Sweden
| | - Laure Saint-Aubert
- Division of Translational Alzheimer Neurobiology, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Stockholm, Sweden
| | - Konstantinos Chiotis
- Division of Translational Alzheimer Neurobiology, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Stockholm, Sweden
| | - Ove Almkvist
- Division of Translational Alzheimer Neurobiology, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Stockholm, Sweden; Department of Geriatric Medicine, Karolinska University Hospital, Huddinge, Sweden; Department of Psychology, Stockholm University, Stockholm, Sweden
| | - Irina Savitcheva
- Department of Radiology, Karolinska University Hospital, Huddinge, Sweden
| | - My Jonasson
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Department of Medical Physics, Uppsala University Hospital, Uppsala, Sweden
| | - Mark Lubberink
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Department of Medical Physics, Uppsala University Hospital, Uppsala, Sweden
| | - Anders Wall
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Gunnar Antoni
- Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Agneta Nordberg
- Division of Translational Alzheimer Neurobiology, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Stockholm, Sweden; Department of Geriatric Medicine, Karolinska University Hospital, Huddinge, Sweden.
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Pasha EP, Tarumi T, Haley AP, Tanaka H. Transcranial Doppler of the middle cerebral artery indicates regional gray matter cerebral perfusion. Physiol Meas 2017; 38:2176-2185. [PMID: 29091052 DOI: 10.1088/1361-6579/aa976f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE We determined if transcranial color-coded Doppler derived hemodynamics are associated with MRI-based cerebral blood flow (CBF) in regions clinically important to dementia in healthy middle-aged adults. APPROACH In 30 subjects (18m/12f; age = 52 ± 1 years), blood flow velocity (BFV) and cerebrovascular conductance (CVC) were measured with transcranial color-coded Doppler (TCCD) at the middle cerebral artery (MCA) and cerebral blood flow (CBF) was assessed with arterial spin labeled perfusion MRI. MAIN RESULTS BFV and CVC were associated with hippocampus (r = 0.58 and r = 0.61, both p < 0.01) and occipitoparietal (r = 0.50 and r = 0.58, both p < 0.01) CBF. CVC was further associated with posterior cingulate CBF (r = 0.58 p < 0.01). Independent of age and sex, BFV and CVC were associated with hippocampus (r = 0.59 and r = 0.55, both p < 0.003) and occipitoparietal (r = 0.50 and r = 0.57, both p < 0.01) CBF. CVC was independently associated with posterior cingulate CBF (r = 0.38, p = 0.049). SIGNIFICANCE TCCD-measured BFV and CVC of the MCA are indicators of cerebral perfusion to clinically valuable brain regions in healthy middle-aged adults. TCCD may not be a good indicator of blood flow to cerebral white matter.
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Affiliation(s)
- Evan P Pasha
- Department of Kinesiology and Health Education, Cardiovascular Aging Research Laboratory, The University of Texas at Austin, Austin, TX 78712, United States of America
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Kirino E. Three-dimensional stereotactic surface projection in the statistical analysis of single photon emission computed tomography data for distinguishing between Alzheimer’s disease and depression. World J Psychiatry 2017; 7:121-127. [PMID: 28713690 PMCID: PMC5491477 DOI: 10.5498/wjp.v7.i2.121] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/10/2017] [Accepted: 05/05/2017] [Indexed: 02/05/2023] Open
Abstract
AIM To evaluate usefulness of single photon emission computed tomography (SPECT) with three-dimensional stereotactic surface projection (3D-SSP) in distinguishing between Alzheimer’s disease (AD) and depression.
METHODS We studied 43 patients who presented with both depressive symptoms and memory disturbance. Each subject was evaluated using the following: (1) the Minimal Mental State Examination; (2) the Hamilton Rating Scale for Depression; (3) Clinical Global Impression-Severity scale (CGI-S); and (4) SPECT imaging with 3D-SSP.
RESULTS The MMSE scores correlated significantly with the maximum Z-scores of AD-associated regions. CGI-S scores correlated significantly with the maximum Z-scores of depression-associated regions. Factor analysis identified three significant factors. Of these, Factor 1 could be interpreted as favouring a tendency for AD, Factor 2 as favouring a tendency for pseudo-dementia, and Factor 3 as favouring a depressive tendency.
CONCLUSION We investigated whether these patients could be categorized as types: Type A (true AD), Type B (pseudo-dementia), Type C (occult AD), and Type D (true depression). The factor scores in factor analysis supported the validity of this classification. Our results suggest that SPECT with 3D-SSP is highly useful for distinguishing between depression and depressed mood in the early stage of AD.
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Hshieh TT, Dai W, Cavallari M, Guttmann CR, Meier DS, Schmitt EM, Dickerson BC, Press DZ, Marcantonio ER, Jones RN, Gou YR, Travison TG, Fong TG, Ngo L, Inouye SK, Alsop DC. Cerebral blood flow MRI in the nondemented elderly is not predictive of post-operative delirium but is correlated with cognitive performance. J Cereb Blood Flow Metab 2017; 37:1386-1397. [PMID: 27401806 PMCID: PMC5453459 DOI: 10.1177/0271678x16656014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Three-dimensional Arterial Spin Labeling (ASL) MRI was performed before surgery in a cohort of 146 prospectively enrolled subjects ≥ 70 years old scheduled to undergo elective surgery. We investigated the prospective association between ASL-derived measures of cerebral blood flow (CBF) before surgery with postoperative delirium incidence and severity using whole-brain and globally normalized voxel-wise analysis. We also investigated the cross-sectional association of CBF with patients' baseline performance on specific neuropsychological tests, and with a composite general cognitive performance measure (GCP). Out of 146 subjects, 32 (22%) developed delirium. We found no significant association between global and voxel-wise CBF with delirium incidence or severity. We found the most significant positive associations between CBF of the posterior cingulate and precuneus and the Hopkins Verbal Learning Test - Revised total score, Visual Search and Attention Test (VSAT) score and the GCP composite. VSAT score was also strongly associated with right parietal lobe CBF. ASL can be employed in a large, well-characterized older cohort to examine associations between CBF and age-related cognitive performance. Although ASL CBF measures in regions previously associated with preclinical Alzheimer's Disease were correlated with cognition, they were not found to be indicators of baseline pathology that may increase risk for delirium.
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Affiliation(s)
- Tammy T Hshieh
- 1 Division of Aging, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,2 Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA
| | - Weiying Dai
- 3 Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.,4 Department of Computer Science, State University of New York at Binghamton, Binghamton, NY, USA
| | - Michele Cavallari
- 5 Center for Neurological Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Charles Rg Guttmann
- 5 Center for Neurological Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Dominik S Meier
- 5 Center for Neurological Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Eva M Schmitt
- 2 Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA
| | - Bradford C Dickerson
- 6 Martinos Center for Biomedical Imaging, Psychiatric Neuroimaging Division, Department of Psychiatry, and Frontotemporal Disorders Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Daniel Z Press
- 7 Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Edward R Marcantonio
- 8 Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Richard N Jones
- 2 Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.,9 Departments of Psychiatry and Human Behavior and Neurology, Brown University Warren Alpert Medical School, Providence, RI, USA
| | - Yun Ray Gou
- 2 Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA
| | - Thomas G Travison
- 2 Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.,8 Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Tamara G Fong
- 2 Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.,7 Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Long Ngo
- 8 Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Sharon K Inouye
- 2 Aging Brain Center, Institute for Aging Research, Hebrew SeniorLife, Boston, MA, USA.,8 Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - David C Alsop
- 3 Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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Michels L, Warnock G, Buck A, Macauda G, Leh SE, Kaelin AM, Riese F, Meyer R, O'Gorman R, Hock C, Kollias S, Gietl AF. Arterial spin labeling imaging reveals widespread and Aβ-independent reductions in cerebral blood flow in elderly apolipoprotein epsilon-4 carriers. J Cereb Blood Flow Metab 2016; 36:581-95. [PMID: 26661143 PMCID: PMC4794091 DOI: 10.1177/0271678x15605847] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 10/07/2015] [Indexed: 12/11/2022]
Abstract
Changes in cerebral blood flow are an essential feature of Alzheimer's disease and have been linked to apolipoprotein E-genotype and cerebral amyloid-deposition. These factors could be interdependent or influence cerebral blood flow via different mechanisms. We examined apolipoprotein E-genotype, amyloid beta-deposition, and cerebral blood flow in amnestic mild cognitive impairment using pseudo-continuous arterial spin labeling MRI in 27 cognitively normal elderly and 16 amnestic mild cognitive impairment participants. Subjects underwent Pittsburgh Compound B (PiB) positron emission tomography and apolipoprotein E-genotyping. Global cerebral blood flow was lower in apolipoprotein E ɛ4-allele carriers (apolipoprotein E4+) than in apolipoprotein E4- across all subjects (including cognitively normal participants) and within the group of cognitively normal elderly. Global cerebral blood flow was lower in subjects with mild cognitive impairment compared with cognitively normal. Subjects with elevated cerebral amyloid-deposition (PiB+) showed a trend for lower global cerebral blood flow. Apolipoprotein E-status exerted the strongest effect on global cerebral blood flow. Regional analysis indicated that local cerebral blood flow reductions were more widespread for the contrasts apolipoprotein E4+ versus apolipoprotein E4- compared with the contrasts PiB+ versus PiB- or mild cognitive impairment versus cognitively normal. These findings suggest that apolipoprotein E-genotype exerts its impact on cerebral blood flow at least partly independently from amyloid beta-deposition, suggesting that apolipoprotein E also contributes to cerebral blood flow changes outside the context of Alzheimer's disease.
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Affiliation(s)
- Lars Michels
- Institute of Neuroradiology, University Hospital Zurich, Zurich, Switzerland Center of MR-Research, University Children's Hospital Zurich, Zurich, Switzerland
| | - Geoffrey Warnock
- Clinic of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Alfred Buck
- Clinic of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Gianluca Macauda
- Institute of Neuroradiology, University Hospital Zurich, Zurich, Switzerland Neuropsychology Unit, Department of Neurology, University Hospital Zurich, Zurich, Switzerland
| | - Sandra E Leh
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| | - Andrea M Kaelin
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| | - Florian Riese
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| | - Rafael Meyer
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| | - Ruth O'Gorman
- Center of MR-Research, University Children's Hospital Zurich, Zurich, Switzerland
| | - Christoph Hock
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
| | - Spyros Kollias
- Institute of Neuroradiology, University Hospital Zurich, Zurich, Switzerland
| | - Anton F Gietl
- Division of Psychiatry Research and Psychogeriatric Medicine, University of Zurich, Zurich, Switzerland
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Bron EE, Steketee RME, Houston GC, Oliver RA, Achterberg HC, Loog M, van Swieten JC, Hammers A, Niessen WJ, Smits M, Klein S. Diagnostic classification of arterial spin labeling and structural MRI in presenile early stage dementia. Hum Brain Mapp 2014; 35:4916-31. [PMID: 24700485 PMCID: PMC6869162 DOI: 10.1002/hbm.22522] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 03/14/2014] [Accepted: 03/24/2014] [Indexed: 11/11/2022] Open
Abstract
Because hypoperfusion of brain tissue precedes atrophy in dementia, the detection of dementia may be advanced by the use of perfusion information. Such information can be obtained noninvasively with arterial spin labeling (ASL), a relatively new MR technique quantifying cerebral blood flow (CBF). Using ASL and structural MRI, we evaluated diagnostic classification in 32 prospectively included presenile early stage dementia patients and 32 healthy controls. Patients were suspected of Alzheimer's disease (AD) or frontotemporal dementia. Classification was based on CBF as perfusion marker, gray matter (GM) volume as atrophy marker, and their combination. These markers were each examined using six feature extraction methods: a voxel-wise method and a region of interest (ROI)-wise approach using five ROI-sets in the GM. These ROI-sets ranged in number from 72 brain regions to a single ROI for the entire supratentorial brain. Classification was performed with a linear support vector machine classifier. For validation of the classification method on the basis of GM features, a reference dataset from the AD Neuroimaging Initiative database was used consisting of AD patients and healthy controls. In our early stage dementia population, the voxelwise feature-extraction approach achieved more accurate results (area under the curve (AUC) range = 86 - 91%) than all other approaches (AUC = 57 - 84%). Used in isolation, CBF quantified with ASL was a good diagnostic marker for dementia. However, our findings indicated only little added diagnostic value when combining ASL with the structural MRI data (AUC = 91%), which did not significantly improve over accuracy of structural MRI atrophy marker by itself.
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Affiliation(s)
- Esther E Bron
- Departments of Medical Informatics and Radiology, Biomedical Imaging Group Rotterdam, Erasmus MC - University Medical Center Rotterdam, the Netherlands
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13
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Deo AK, Borson S, Link JM, Domino K, Eary JF, Ke B, Richards TL, Mankoff DA, Minoshima S, O'Sullivan F, Eyal S, Hsiao P, Maravilla K, Unadkat JD. Activity of P-Glycoprotein, a β-Amyloid Transporter at the Blood-Brain Barrier, Is Compromised in Patients with Mild Alzheimer Disease. J Nucl Med 2014; 55:1106-11. [PMID: 24842892 DOI: 10.2967/jnumed.113.130161] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 03/17/2014] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Studies in animals and postmortem human brain tissue support a role for P-glycoprotein in clearance of cerebral β-amyloid across the blood-brain barrier (BBB). We tested the hypothesis that BBB P-glycoprotein activity is diminished in Alzheimer disease (AD) by accounting for an AD-related reduction in regional cerebral blood flow (rCBF). METHODS We compared P-glycoprotein activity in mild-AD patients (n = 9) and cognitively normal, age-matched controls (n = 9) using PET with a labeled P-glycoprotein substrate, (11)C-verapamil, and (15)O-water to measure rCBF. BBB P-glycoprotein activity was expressed as the (11)C-verapamil radioactivity extraction ratio ((11)C-verapamil brain distributional clearance, K1/rCBF). RESULTS Compared with controls, BBB P-glycoprotein activity was significantly lower in the parietotemporal, frontal, and posterior cingulate cortices and hippocampus of mild AD subjects. CONCLUSION BBB P-glycoprotein activity in brain regions affected by AD is reduced and is independent of rCBF. This study improves on prior work by eliminating the confounding effect that reduced rCBF has on assessment of BBB P-glycoprotein activity and suggests that impaired P-glycoprotein activity may contribute to cerebral β-amyloid accumulation in AD. P-glycoprotein induction or activation to increase cerebral β-amyloid clearance could constitute a novel preventive or therapeutic strategy for AD.
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Affiliation(s)
- Anand K Deo
- Department of Pharmaceutics, University of Washington, Seattle, Washington
| | - Soo Borson
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington
| | - Jeanne M Link
- Department of Radiology, University of Washington, Seattle, Washington
| | - Karen Domino
- Department of Anesthesiology, University of Washington, Seattle, Washington; and
| | - Janet F Eary
- Department of Radiology, University of Washington, Seattle, Washington
| | - Ban Ke
- Department of Pharmaceutics, University of Washington, Seattle, Washington
| | - Todd L Richards
- Department of Radiology, University of Washington, Seattle, Washington
| | - David A Mankoff
- Department of Radiology, University of Washington, Seattle, Washington
| | - Satoshi Minoshima
- Department of Radiology, University of Washington, Seattle, Washington
| | - Finbarr O'Sullivan
- Department of Radiology, University of Washington, Seattle, Washington Department of Statistics, University College Cork, Cork, Ireland
| | - Sara Eyal
- Department of Pharmaceutics, University of Washington, Seattle, Washington
| | - Peng Hsiao
- Department of Pharmaceutics, University of Washington, Seattle, Washington
| | - Ken Maravilla
- Department of Radiology, University of Washington, Seattle, Washington
| | - Jashvant D Unadkat
- Department of Pharmaceutics, University of Washington, Seattle, Washington
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14
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Mattsson N, Tosun D, Insel PS, Simonson A, Jack CR, Beckett LA, Donohue M, Jagust W, Schuff N, Weiner MW. Association of brain amyloid-β with cerebral perfusion and structure in Alzheimer's disease and mild cognitive impairment. ACTA ACUST UNITED AC 2014; 137:1550-61. [PMID: 24625697 DOI: 10.1093/brain/awu043] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Patients with Alzheimer's disease have reduced cerebral blood flow measured by arterial spin labelling magnetic resonance imaging, but it is unclear how this is related to amyloid-β pathology. Using 182 subjects from the Alzheimer's Disease Neuroimaging Initiative we tested associations of amyloid-β with regional cerebral blood flow in healthy controls (n = 51), early (n = 66) and late (n = 41) mild cognitive impairment, and Alzheimer's disease with dementia (n = 24). Based on the theory that Alzheimer's disease starts with amyloid-β accumulation and progresses with symptoms and secondary pathologies in different trajectories, we tested if cerebral blood flow differed between amyloid-β-negative controls and -positive subjects in different diagnostic groups, and if amyloid-β had different associations with cerebral blood flow and grey matter volume. Global amyloid-β load was measured by florbetapir positron emission tomography, and regional blood flow and volume were measured in eight a priori defined regions of interest. Cerebral blood flow was reduced in patients with dementia in most brain regions. Higher amyloid-β load was related to lower cerebral blood flow in several regions, independent of diagnostic group. When comparing amyloid-β-positive subjects with -negative controls, we found reductions of cerebral blood flow in several diagnostic groups, including in precuneus, entorhinal cortex and hippocampus (dementia), inferior parietal cortex (late mild cognitive impairment and dementia), and inferior temporal cortex (early and late mild cognitive impairment and dementia). The associations of amyloid-β with cerebral blood flow and volume differed across the disease spectrum, with high amyloid-β being associated with greater cerebral blood flow reduction in controls and greater volume reduction in late mild cognitive impairment and dementia. In addition to disease stage, amyloid-β pathology affects cerebral blood flow across the span from controls to dementia patients. Amyloid-β pathology has different associations with cerebral blood flow and volume, and may cause more loss of blood flow in early stages, whereas volume loss dominates in late disease stages.
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Affiliation(s)
- Niklas Mattsson
- 1 Department of Veterans Affairs Medical Centre, Centre for Imaging of Neurodegenerative Diseases, San Francisco, CA, USA
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15
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Tosun D, Joshi S, Weiner MW. Multimodal MRI-based Imputation of the Aβ+ in Early Mild Cognitive Impairment. Ann Clin Transl Neurol 2014; 1:160-170. [PMID: 24729983 PMCID: PMC3981105 DOI: 10.1002/acn3.40] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Objective The primary goal of this study was to identify brain atrophy from structural MRI (magnetic resonance imaging) and cerebral blood flow (CBF) patterns from arterial spin labeling perfusion MRI that are best predictors of the Aβ-burden, measured as composite 18F-AV45-PET (positron emission tomography) uptake, in individuals with early mild cognitive impairment (MCI). Furthermore, another objective was to assess the relative importance of imaging modalities in classification of Aβ+/Aβ− early MCI. Methods Sixty-seven Alzheimer's Disease Neuroimaging Initiative (ADNI)-GO/2 participants with early MCI were included. Voxel-wise anatomical shape variation measures were computed by estimating the initial diffeomorphic mapping momenta from an unbiased control template. CBF measures normalized to average motor cortex CBF were mapped onto the template space. Using partial least squares regression, we identified the structural and CBF signatures of Aβ after accounting for normal cofounding effects of age, gender, and education. Results 18F-AV45-positive early MCIs could be identified with 83% classification accuracy, 87% positive predictive value, and 84% negative predictive value by multidisciplinary classifiers combining demographics data, ApoE ε4-genotype, and a multimodal MRI-based Aβ score. Interpretation Multimodal MRI can be used to predict the amyloid status of early-MCI individuals. MRI is a very attractive candidate for the identification of inexpensive and noninvasive surrogate biomarkers of Aβ deposition. Our approach is expected to have value for the identification of individuals likely to be Aβ+ in circumstances where cost or logistical problems prevent Aβ detection using cerebrospinal fluid analysis or Aβ-PET. This can also be used in clinical settings and clinical trials, aiding subject recruitment and evaluation of treatment efficacy. Imputation of the Aβ-positivity status could also complement Aβ-PET by identifying individuals who would benefit the most from this assessment.
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Affiliation(s)
- Duygu Tosun
- Department of Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA USA
| | - Sarang Joshi
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT 84112, USA (72 S Central Campus Drive, Room 3750, Salt Lake City, UT 84112)
| | - Michael W Weiner
- Department of Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA USA
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16
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Arterial spin labeled MRI in prodromal Alzheimer's disease: A multi-site study. NEUROIMAGE-CLINICAL 2013; 2:630-6. [PMID: 24179814 PMCID: PMC3777751 DOI: 10.1016/j.nicl.2013.04.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/18/2013] [Accepted: 04/20/2013] [Indexed: 01/17/2023]
Abstract
We examined differences in cerebral blood flow (CBF) measured by Arterial Spin Labeled perfusion MRI (ASL MRI) across the continuum from cognitively normal (CN) older adults to mild Alzheimer's Disease (AD) using data from the multi-site Alzheimer's Disease Neuroimaging Initiative (ADNI). Measures of CBF, in a predetermined set of regions (meta-ROI), and hippocampal volume were compared between CN (n = 47), patients with early and late Mild Cognitive Impairment [EMCI (n = 32), LMCI (n = 35)], and AD (n = 15). Associations between these measures and disease severity, assessed by Clinical Dementia Rating scale sum of boxes (CDR SB), were also assessed. Mean meta-ROI CBF was associated with group status and significant hypoperfusion was observed in LMCI and AD relative to CN. Hippocampal volume was associated with group status, but only AD patients had significantly smaller volumes than the CN. When examining the relationship between these measures and disease severity, both were significantly associated with CDR SB and appeared to provide independent prediction of status. In light of the tight link between CBF and metabolism, ASL MRI represents a promising functional biomarker for early diagnosis and disease tracking in AD and this study is the first to demonstrate the feasibility in a multi-site context in this population. Combining functional and structural measures, which can be acquired in the same scanning session, appears to provide additional information about disease severity relative to either measure alone.
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17
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Tsukamoto M, Hatabu A, Takahashi Y, Matsuda H, Okamoto K, Yamashita N, Takagi T. Statistical Evaluation of Single-Photon Emission Computed Tomography Image Using Smoothed Bootstrap Method. Biol Pharm Bull 2013; 36:417-24. [DOI: 10.1248/bpb.b12-00843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Asuka Hatabu
- Faculty of Pharmaceutical Sciences, Osaka University
| | | | - Hiroshi Matsuda
- Department of Radiology, National Center Hospital for Mental, Nervous, and Muscular Disorders, National Center of Neurology and Psychiatry
| | - Kousuke Okamoto
- Graduate School of Pharmaceutical Sciences, Osaka University
| | | | - Tatsuya Takagi
- Graduate School of Pharmaceutical Sciences, Osaka University
- Genome Information Research Center, Osaka University
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18
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Alegret M, Vinyes-Junqué G, Boada M, Martínez-Lage P, Cuberas G, Espinosa A, Roca I, Hernández I, Valero S, Rosende-Roca M, Mauleón A, Becker And JT, Tárraga L. Brain perfusion correlates of visuoperceptual deficits in mild cognitive impairment and mild Alzheimer's disease. J Alzheimers Dis 2010; 21:557-67. [PMID: 20555146 DOI: 10.3233/jad-2010-091069] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Visuoperceptual processing is impaired early in the clinical course of Alzheimer's disease (AD). The 15-Objects Test (15-OT) detects such subtle performance deficits in mild cognitive impairment (MCI) and mild AD. Reduced brain perfusion in the temporal, parietal, and prefrontal regions have been found in early AD and MCI patients. The objectives of this study were to confirm the role of the 15-OT in the diagnosis of MCI and AD and to investigate the brain perfusion correlates of visuoperceptual dysfunction (15-OT) in subjects with MCI, AD, and normal aging. Forty-two AD, 42 MCI, and 42 healthy elderly control subjects underwent a brain Single Photon Emission Tomography (SPECT) and separately completed the 15-OT. An analysis of variance compared 15-OT scores between groups. SPM5 was used to analyse the SPECT data. 15-OT performance was impaired in the MCI and AD patients. In terms of the SPECT scans, AD patients showed reduced perfusion in temporal-parietal regions, while the MCI subjects had decreased perfusion in the middle and posterior cingulate. When MCI and AD groups were compared, a significant brain perfusion reduction was found in temporo-parietal regions. In the whole sample, 15-OT performance was significantly correlated with the clinical dementia rating scores, and with the perfusion in the bilateral posterior cingulate and the right temporal pole, with no significant correlation in each separate group. Our findings suggest that the 15-OT performance provides a useful gradation of impairment from normal aging to AD, and it seems to be related to perfusion in the bilateral posterior cingulate and the right temporal pole.
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Affiliation(s)
- Montserrat Alegret
- Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain.
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19
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Chen W, Song X, Beyea S, D'Arcy R, Zhang Y, Rockwood K. Advances in perfusion magnetic resonance imaging in Alzheimer's disease. Alzheimers Dement 2010; 7:185-96. [DOI: 10.1016/j.jalz.2010.04.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 03/31/2010] [Accepted: 04/21/2010] [Indexed: 01/01/2023]
Affiliation(s)
- Wei Chen
- National Research Council CanadaInstitute for Biodiagnostics (Atlantic)HalifaxCanada
- Department of RadiologyGeneral Hospital of Tianjin Medical UniversityTianjinChina
| | - Xiaowei Song
- National Research Council CanadaInstitute for Biodiagnostics (Atlantic)HalifaxCanada
- Division of Geriatric MedicineDepartment of Medicine, Dalhousie UniversityHalifaxCanada
| | - Steven Beyea
- National Research Council CanadaInstitute for Biodiagnostics (Atlantic)HalifaxCanada
- Department of PhysicsDalhousie UniversityHalifaxCanada
| | - Ryan D'Arcy
- National Research Council CanadaInstitute for Biodiagnostics (Atlantic)HalifaxCanada
- Department of PsychologyDalhousie UniversityHalifaxCanada
- Neuroscience Institute, Dalhousie UniversityHalifaxCanada
| | - Yunting Zhang
- Department of RadiologyGeneral Hospital of Tianjin Medical UniversityTianjinChina
| | - Kenneth Rockwood
- Division of Geriatric MedicineDepartment of Medicine, Dalhousie UniversityHalifaxCanada
- Centre for Health Care of the Elderly, Queen Elizabeth II Health Sciences CentreHalifaxCanada
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20
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Yoshiura T, Hiwatashi A, Yamashita K, Ohyagi Y, Monji A, Takayama Y, Nagao E, Kamano H, Noguchi T, Honda H. Simultaneous measurement of arterial transit time, arterial blood volume, and cerebral blood flow using arterial spin-labeling in patients with Alzheimer disease. AJNR Am J Neuroradiol 2009; 30:1388-93. [PMID: 19342545 DOI: 10.3174/ajnr.a1562] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Cerebral hemodynamics abnormality in Alzheimer disease (AD) is not fully understood. Our aim was to determine whether regional hypoperfusion due to AD is associated with abnormalities in regional arterial blood volume (rABV) and regional arterial transit time (rATT) as measured by quantitative arterial spin-labeling (ASL) with multiple-delay time sampling. MATERIALS AND METHODS Nineteen patients with AD (9 men and 10 women; mean age, 74.5 +/- 8.6 years) and 22 cognitively healthy control subjects (11 men and 11 women; mean age, 72.8 +/- 6.8 years) were studied by using a quantitative ASL method with multiple-delay time sampling. From the ASL data, maps of regional cerebral blood flow (rCBF), rABV, and rATT were generated. A region of hypoperfusion due to AD was determined by statistical parametric mapping (SPM) analysis. Mean rCBF, rABV, and rATT values within the hypoperfused region were compared between the AD and control groups. RESULTS Despite the significantly lower rCBF (P = .0004) in patients with AD (27.8 +/- 7.1 mL/100 g/min) in comparison with control subjects (36.7 +/- 6.3 mL/100 g/min), no significant difference in rATT was observed between the control (0.48 +/- 0.09 seconds) and AD (0.47 +/- 0.10 seconds) groups. Mean rABV was lower in the AD group (0.22 +/- 0.10%) than in the control group (0.27 +/- 0.12%), though the difference did not reach the level of statistical significance. CONCLUSIONS Our results revealed that regional hypoperfusion in AD is not associated with rATT prolongation, suggesting that the mechanism of hypoperfusion is distinct from that in cerebrovascular diseases.
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Affiliation(s)
- T Yoshiura
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
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21
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Uh J, Lewis-Amezcua K, Martin-Cook K, Cheng Y, Weiner M, Diaz-Arrastia R, Devous M, Shen D, Lu H. Cerebral blood volume in Alzheimer's disease and correlation with tissue structural integrity. Neurobiol Aging 2009; 31:2038-46. [PMID: 19200623 DOI: 10.1016/j.neurobiolaging.2008.12.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 11/25/2008] [Accepted: 12/22/2008] [Indexed: 11/15/2022]
Abstract
A vascular component is increasingly recognized as important in Alzheimer's disease (AD). We measured cerebral blood volume (CBV) in patients with probable AD or Mild Cognitive Impairment (MCI) and in elderly non-demented subjects using a recently developed Vascular-Space-Occupancy (VASO) MRI technique. While both gray and white matters were examined, significant CBV deficit regions were primarily located in white matter, specifically in frontal and parietal lobes, in which CBV was reduced by 20% in the AD/MCI group. The regions with CBV deficit also showed reduced tissue structural integrity as indicated by increased apparent diffusion coefficients, whereas in regions without CBV deficits no such correlation was found. Subjects with lower CBV tended to have more white matter lesions in FLAIR MRI images and showed slower psychomotor speed. These data suggest that the vascular contribution in AD is primarily localized to frontal/parietal white matter and is associated with brain tissue integrity.
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Affiliation(s)
- Jinsoo Uh
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
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22
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Bagurdes LA, Mesulam MM, Gitelman DR, Weintraub S, Small DM. Modulation of the spatial attention network by incentives in healthy aging and mild cognitive impairment. Neuropsychologia 2008; 46:2943-8. [DOI: 10.1016/j.neuropsychologia.2008.06.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2007] [Revised: 04/28/2008] [Accepted: 06/04/2008] [Indexed: 11/30/2022]
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Braskie MN, Small GW, Bookheimer SY. Vascular health risks and fMRI activation during a memory task in older adults. Neurobiol Aging 2008; 31:1532-42. [PMID: 18829134 DOI: 10.1016/j.neurobiolaging.2008.08.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 06/19/2008] [Accepted: 08/24/2008] [Indexed: 11/17/2022]
Abstract
Vascular problems increase Alzheimer's disease (AD) risk, but the nature of this relationship remains unclear. Older adults having genetic risk for AD show regionally increased functional magnetic resonance imaging (fMRI) activity during memory, possibly representing compensation for a genetically induced neural deficit. We investigated whether vascular health risks, which similarly could lead to neuropsychological deficits, also showed increased fMRI activity during a memory task performed by 30 cognitively intact, primarily normotensive older adults (mean age=61). Vascular risk measures included systolic blood pressure (sBP), body mass index (BMI), and total cholesterol. Higher sBP and BMI (but not total cholesterol) were significantly correlated with increased activation in posterior cingulate cortex and frontal, temporal, and parietal regions. In posterior cingulate and parietal cortices, these relationships were evident even within sBP and BMI ranges considered normal, and were independent of hippocampal volume. Our results are similar to those in prior AD risk research, and suggest that fMRI reveals an abnormal response to cognitive processes in cognitively intact older adults with increased vascular risk.
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Affiliation(s)
- Meredith N Braskie
- Ahmanson-Lovelace Brain Mapping Center, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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24
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Riha PD, Rojas JC, Colorado RA, Gonzalez-Lima F. Animal model of posterior cingulate cortex hypometabolism implicated in amnestic MCI and AD. Neurobiol Learn Mem 2008; 90:112-24. [PMID: 18316212 DOI: 10.1016/j.nlm.2008.01.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Revised: 01/16/2008] [Accepted: 01/17/2008] [Indexed: 11/29/2022]
Abstract
The posterior cingulate cortex (PCC) is the brain region displaying the earliest sign of energy hypometabolism in patients with amnestic mild cognitive impairment (MCI) who develop Alzheimer's disease (AD). In particular, the activity of the mitochondrial respiratory enzyme cytochrome oxidase (C.O.) is selectively inhibited within the PCC in AD. The present study is the first experimental analysis designed to model in animals the localized cortical C.O. inhibition found as the earliest metabolic sign of early-stage AD in human neuroimaging studies. Rats were used to model local inhibition of C.O. by direct injection of the C.O. inhibitor sodium azide into the PCC. Learning and memory were examined in a spatial holeboard task and brains were analyzed using quantitative histochemical, morphological and biochemical techniques. Behavioral results showed that sodium azide-treated rats were impaired in their memory of the baited pattern in probe trials as compared to their training scores before treatment, without non-specific behavioral differences. Brain analyses showed that C.O. inhibition was specific to the PCC, and sodium azide increased lipid peroxidation, gliosis and neuron loss, and lead to a network functional disconnection between the PCC and interconnected hippocampal regions. It was concluded that impaired memory by local C.O. inhibition in the PCC may serve to model in animals a metabolic lesion similar to that found in patients with amnestic MCI and early-stage AD. This model may be useful as an in vivo testing platform to investigate neuroprotective strategies to prevent or reduce the amnestic effects produced by posterior cingulate energy hypometabolism.
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Affiliation(s)
- P D Riha
- Department of Psychology, University of Texas, 1 University Station A8000, Austin, TX 78712, USA
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Zobel A, Joe A, Freymann N, Clusmann H, Schramm J, Reinhardt M, Biersack HJ, Maier W, Broich K. Changes in regional cerebral blood flow by therapeutic vagus nerve stimulation in depression: an exploratory approach. Psychiatry Res 2005; 139:165-79. [PMID: 16043331 DOI: 10.1016/j.pscychresns.2005.02.010] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2003] [Revised: 11/16/2004] [Accepted: 02/28/2005] [Indexed: 01/31/2023]
Abstract
Abnormalities in regional cerebral blood flow (rCBF) have been reported to characterize depressive episodes; they are at least partly reversed by antidepressant treatment. Treatment-specific as well as response-related changes in rCBF have been reported. We explored the changes in rCBF induced by vagus nerve stimulation (VNS), a recently proposed antidepressant strategy, by application of single photon emission-computed tomography with (99m)Tc-hexamethyl-propylene amine oxime in otherwise treatment-refractory patients. Both region-of-interest (ROI) and statistical parametric mapping (SPM) analytic approaches were used. Decreases of rCBF in the amygdala, left hippocampus, left subgenual cingulate cortex, left and right ventral anterior cingulum, right thalamus and brain stem were observed; the only increase of rCBF was found by SPM analysis in the middle frontal gyrus. This pattern shares features with changes of rCBF previously associated with the administration of selective serotonin reuptake inhibitors. Similarities to other brain-stimulation strategies in antidepressant treatment were less pronounced.
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Affiliation(s)
- Astrid Zobel
- Department of Psychiatry, University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.
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26
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Ishii K, Sasaki H, Kono AK, Miyamoto N, Fukuda T, Mori E. Comparison of gray matter and metabolic reduction in mild Alzheimer's disease using FDG-PET and voxel-based morphometric MR studies. Eur J Nucl Med Mol Imaging 2005; 32:959-63. [PMID: 15800784 DOI: 10.1007/s00259-004-1740-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Accepted: 11/19/2004] [Indexed: 11/25/2022]
Abstract
PURPOSE The aim of this study was to investigate regional differences between morphologic and functional changes in the same patients with mild Alzheimer's disease (AD) using statistical parametric mapping (SPM) and voxel-based morphometry (VBM). METHODS Thirty patients with very mild AD (mean age 66.8 years, mean MMSE score 24.0) and 30 age- and sex-matched normal volunteers underwent both( 18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and three-dimensional spoiled gradient echo (SPGR) magnetic resonance imaging (MRI). Statistical parametric mapping was used to conduct VBM analysis of the morphological data, which were compared voxel by voxel with the results of a similar analysis of the glucose metabolic data. RESULTS In AD patients, VBM data indicated a significant gray matter volume density decrease in bilateral amygdala/hippocampus complex (p < 0.05, corrected), while FDG-PET analysis showed significant glucose metabolic reductions in the posterior cingulate gyri and the right parietal lobule, compared with those in the normal control group. CONCLUSION In very mild AD, morphological change occurs in the medial temporal lobes, while in contrast, metabolic changes occur in the posterior cingulate gyri and parietal lobule.
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Affiliation(s)
- Kazunari Ishii
- Department of Radiology and Nuclear Medicine, Hyogo Brain and Heart Center, 520 Saisho-Ko, Himeji, Hyogo, 670-0981, Japan.
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Maalikjy Akkawi N, Borroni B, Agosti C, Magoni M, Broli M, Pezzini A, Padovani A. Volume cerebral blood flow reduction in pre-clinical stage of Alzheimer disease: evidence from an ultrasonographic study. J Neurol 2005; 252:559-63. [PMID: 15726249 DOI: 10.1007/s00415-005-0689-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Revised: 09/10/2004] [Accepted: 10/05/2004] [Indexed: 10/25/2022]
Abstract
The association of decreased cerebral blood flow with the development of Alzheimer's disease (AD) has been a recent target of interest. By using neuroimaging techniques, growing attention has been devoted to the identification of preclinical AD. In this study, color duplex sonography of cervical arteries was used to measure mean cerebral blood flow (CBF) on 55 amnestic Mild Cognitive Impairment (MCI) patients. Two years after enrollment, excluding patients who progressed to dementia other than AD, two subgroups were identified, patients who developed AD (MCI converters) and patients with preserved cognitive and functional level (MCI non-converters). Examining the mean difference of CBF measured at baseline in the two subgroups obtained, a significant difference was noticed (MCI converters 539.3 +/- 114.3 vs MCI non converters 636.0 +/- 143.9, p < 0.05). MCI patients with CBF higher than median value (558 ml/min) had lower risk of developing AD (specificity 72.2%, sensitivity 68.4%) within a two year follow-up. Ultrasonography of the cervical arteries is a simple, non invasive and widespread technique useful in detecting CBF decline during the MCI stage, thus identifying patients who later will convert to AD.
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Affiliation(s)
- Nabil Maalikjy Akkawi
- Dept. of Neurological Sciences, University of Brescia, P.za Spedali Civili, 1, 25100 Brescia, Italy.
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28
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Scarmeas N, Habeck CG, Zarahn E, Anderson KE, Park A, Hilton J, Pelton GH, Tabert MH, Honig LS, Moeller JR, Devanand DP, Stern Y. Covariance PET patterns in early Alzheimer's disease and subjects with cognitive impairment but no dementia: utility in group discrimination and correlations with functional performance. Neuroimage 2004; 23:35-45. [PMID: 15325350 PMCID: PMC3026571 DOI: 10.1016/j.neuroimage.2004.04.032] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2003] [Revised: 03/20/2004] [Accepted: 04/28/2004] [Indexed: 10/26/2022] Open
Abstract
Although multivariate analytic techniques might identify diagnostic patterns that are not captured by univariate methods, they have rarely been used to study the neural correlates of Alzheimer's disease (AD) or cognitive impairment. Nonquantitative H2(15)O PET scans were acquired during rest in 17 probable AD subjects selected for mild severity [mean-modified Mini Mental Status Examination (mMMS) 46/57; SD 5.1], 16 control subjects (mMMS 54; SD 2.5) and 23 subjects with minimal to mild cognitive impairment but no dementia (mMMS 53; SD 2.8). Expert clinical reading had low success in discriminating AD and controls. There were no significant mean flow differences among groups in traditional univariate SPM Noxel-wise analyses or region of interest (ROI) analyses. A covariance pattern was identified whose mean expression was significantly higher in the AD as compared to controls (P = 0.03; sensitivity 76-94%; specificity 63-81%). Sites of increased concomitant flow included insula, cuneus, pulvinar, lingual, fusiform, superior occipital and parahippocampal gyri, whereas decreased concomitant flow was found in cingulate, inferior parietal lobule, middle and inferior frontal, supramarginal and precentral gyri. The covariance analysis-derived pattern was then prospectively applied to the cognitively impaired subjects: as compared to subjects with Clinical Dementia Rating (CDR) = 0, subjects with CDR = 0.5 had significantly higher mean covariance pattern expression (P = 0.009). Expression of this pattern correlated inversely with Selective Reminding Test total recall (r = -0.401, P = 0.002), delayed recall (r = -0.351, P = 0.008) and mMMS scores (r = -0.401, P = 0.002) in all three groups combined. We conclude that patients with AD may differentially express resting cerebral blood flow covariance patterns even at very early disease stages. Significant alterations in expression of resting flow covariance patterns occur even for subjects with cognitive impairment. Expression of covariance patterns correlates with cognitive and functional performance measures, holding promise for meaningful associations with underlying biopathological processes.
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Affiliation(s)
- Nikolaos Scarmeas
- Cognitive Neuroscience Division of the Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA.
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29
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Bonne O, Louzoun Y, Aharon I, Krausz Y, Karger H, Lerer B, Bocher M, Freedman N, Chisin R. Cerebral blood flow in depressed patients: a methodological comparison of statistical parametric mapping and region of interest analyses. Psychiatry Res 2003; 122:49-57. [PMID: 12589882 DOI: 10.1016/s0925-4927(02)00103-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Functional brain imaging has assumed a leading role in neuropsychiatric research. However, findings reported for mental disorders often vary. Whether this reflects diversity in pathophysiology or heterogeneity of imaging techniques and data-analytic procedures is still unknown. This study compares region of interest (ROI) and statistical parametric mapping (SPM) analyses of a Tc99m-HMPAO single photon emission computed tomography (SPECT) imaging study of 23 depressed and 21 control subjects. Reduced regional cerebral blood flow (rCBF) was demonstrated by both methods in the right parietal and occipital lobes, but additional regions were identified only on ROI analysis (left temporal) and only on SPM analysis (left parietal). To investigate the contribution of SPM spatial normalization to these discrepancies, further ROI analyses were performed, applying the original ROI templates to normalized images, and applying regions identified by SPM to the original images. This study demonstrated considerable overlap in findings of SPM and ROI analyses. Differences between these methods may be mostly related to subjective placement of ROIs in ROI analysis, and standardized warping inherent in normalization in SPM. Given the advantages and drawbacks of each procedure, the choice of methodology should be determined in accordance with the study design, and complementary use of both methods may be considered.
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Affiliation(s)
- Omer Bonne
- Department of Psychiatry, Hadassah Hebrew University Hospital, Kiryat Hadassah, PO Box 12000, Jerusalem 91120, Israel.
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Royall DR, Palmer R, Mulroy AR, Polk MJ, Román GC, David JP, Delacourte A. Pathological determinants of the transition to clinical dementia in Alzheimer's disease. Exp Aging Res 2002; 28:143-62. [PMID: 11928525 DOI: 10.1080/03610730252800166] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The authors developed multivariate models to examine the association between Clinical Dementia Rating (CDR) scale scores and the spatial distribution of paired helical filament tau (PHF-tau) pathology. Severity of tauopathy was examined in 14 cortical regions of interest (ROIs). Classification trees were used to test the independent hierarchical contributions of each ROI to dementia. Multiple-regression and cluster analyses were performed to determine the relative contributions of select ROIs to dementia. Dementia (CDR > or = 1) was modeled as a dichotomous variable. Autopsy material was obtained from 124 demented and nondemented elderly patients. All ROIs except the hippocampus made significant contributions to dementia. However, they were not independent. In multivariate models, only a single step (Step 7 in a hierarchical progression), which contained four ROIs, contributed significantly to dementia. A classification tree resulted in a single decision split, suggesting that only Step 7 ROIs need be considered. A total of 89.4% of the cases were correctly classified (p < .0001). Twelve discrepant cases all had superimposed vasculopathy that might also have affected the function of Step 7 ROIs. The transition to clinical dementia was associated with the presence of tauopathy in A9/10, A22, A23, and A39. Animal studies suggest that these represent a single distributed cortical network focusing on prefrontal regions that provide "executive control" over complex goal-directed behaviors. A22, A23, and A39 provide major afferents to other frontal systems and have previously been implicated in very early clinical Alzheimer's disease.
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Affiliation(s)
- Donald R Royall
- Departments of Psychiatry, Medicine, and Pharmacology, South Texas Veterans' Health System, Audie L. Murphy Division GRECC, University of Texas Health Science Center, San Antonio, Texas, USA
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Volkow ND, Zhu W, Felder CA, Mueller K, Welsh TF, Wang GJ, de Leon MJ. Changes in brain functional homogeneity in subjects with Alzheimer's disease. Psychiatry Res 2002; 114:39-50. [PMID: 11864808 DOI: 10.1016/s0925-4927(01)00130-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Imaging studies have reported marked reductions in brain glucose metabolism in Alzheimer's Disease (AD). However, less is known about disruptions in the patterns of brain metabolic activity. Here we questioned whether AD affects the patterns of homogeneity/heterogeneity in brain metabolism. PET images of 35 AD subjects were compared with those of 35 controls. A template was applied to extract a cortical rim, which was partitioned into 990 contiguous regions. Estimates of metabolic homogeneity were obtained using the coefficient of variation (CV). The CV of the entire cortex was found to be significantly larger in AD, suggesting increased heterogeneity at the whole brain level. In contrast, regional CV was significantly lower in AD in temporal and parietal cortices, which were the regions that along with the precuneus had the largest metabolic decrements, though the precuneus had increased CV. The enhanced heterogeneity for the global cortical pattern most likely reflects variability in the degree of pathology among brain regions as well as neuroanatomical disconnection. The enhanced homogeneity in parietal and temporal cortices is likely to reflect loss of regional differentiation (i.e. macrocolumnar disorganization). The enhanced CV in precuneus, despite its marked reductions in metabolism, suggests that increases in regional homogeneity in parietal and temporal cortices are not a mere reflection of the decrement in metabolism.
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Affiliation(s)
- Nora D Volkow
- Medical Department, Bldg. 490, Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000, USA.
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Energy hypometabolism in posterior cingulate cortex of Alzheimer's patients: superficial laminar cytochrome oxidase associated with disease duration. J Neurosci 2001. [PMID: 11425920 DOI: 10.1523/jneurosci.21-13-04923.2001] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Among brain regions affected in Alzheimer's disease (AD), the posterior cingulate shows the earliest and largest decrement in energy metabolism. Positron emission tomography (PET) studies have shown that these decrements appear before the onset of memory deficits or other symptoms in persons at genetic risk for AD. This study compares in vivo imaging results and in situ postmortem analyses by examining the posterior cingulate (area 23) in 15 AD patients and 13 age-matched nondemented controls using quantitative cytochrome oxidase histochemistry as an intracellular measure of oxidative energy metabolic capacity. Each of the six layers of the posterior cingulate demonstrated a decline in cytochrome oxidase activity in AD relative to controls, whereas adjacent motor cortex showed no significant differences. This decrement did not appear to be mainly secondary to nonspecific decrement in mitochondrial enzymes, oxidative stress, cell loss, or histopathology. The cytochrome oxidase decrement was most severe in the superficial layer I (-39%), which demonstrated a correlation to disease duration. Covariance analyses suggest that superficial laminas undergo a functional uncoupling from the deeper layers of posterior cingulate cortex in AD, whereas no such effects are found in motor cortex or controls. These findings expand on previous results from PET studies by illuminating the layer-specific cytochrome oxidase contributions to energy hypometabolism. The findings suggest a decrement of cytochrome oxidase in posterior cingulate cortex, with progressive reduction within the superficial laminas linked to disease duration. Such decrement could contribute to some of the behavioral symptoms displayed by AD patients. This decrement appeared greater in women.
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