Cross-sectional and longitudinal associations between total and regional white matter hyperintensity volume and cognitive and motor function in Parkinson's disease.

Background: White matter hyperintensities (WMH) are frequently observed on T2-weighted brain magnetic resonance imaging studies of healthy older adults and have been linked with impairments in balance, gait, and cognition. Nonetheless, few studies have investigated the longitudinal effects of comorbid WMH on cognition and motor function in Parkinson's disease.

Methods: The Lesion Segmentation Tool for Statistical Parametric Mapping was used to obtain total lesion volume and map regional WMH probabilities in 29 PD and 42 control participants at two study visits 18 months apart.

Longitudinal white matter microstructural change in Parkinson's disease.

Postmortem studies of Parkinson's disease (PD) suggest that Lewy body pathology accumulates in a predictable topographical sequence, beginning in the olfactory bulb, followed by caudal brainstem, substantia nigra, limbic cortex, and neocortex. Diffusion-weighted imaging (DWI) is sensitive, if not specific, to early disease-related white matter (WM) change in a variety of traumatic and degenerative brain diseases. Although numerous cross-sectional studies have reported DWI differences in cerebral WM in PD, only a few longitudinal studies have investigated whether DWI change exceeds that of normal aging or coincides with regional Lewy body accumulation.

Arterial spin labeling reveals relationships between resting cerebral perfusion and motor learning in Parkinson's disease.

Parkinson's disease (PD) is an age-related neurodegenerative disease that produces changes in movement, cognition, sleep, and autonomic function. Motor learning involves acquisition of new motor skills through practice, and is affected by PD. The purpose of the present study was to evaluate regional differences in resting cerebral blood flow (rCBF), measured using arterial spin labeling (ASL) MRI, during a finger-typing task of motor skill acquisition in PD patients compared to age- and gender-matched controls.

Alterations of Myelin Content in Parkinson's Disease: A Cross-Sectional Neuroimaging Study.

Alterations to myelin may be a core pathological feature of neurodegenerative diseases. Although white matter microstructural differences have been described in Parkinson's disease (PD), it is unknown whether such differences include alterations of the brain's myelin content. Thus, the objective of the current study is to measure and compare brain myelin content between PD patients and age-matched controls.

Voxelwise Relationships Between Distribution Volume Ratio and Cerebral Blood Flow: Implications for Analysis of β-Amyloid Images.

Unlabelled: Quantification of β-amyloid (Aβ) in vivo is often accomplished using the distribution volume ratio (DVR), based on a simplified reference tissue model. We investigated the local relationships between DVR and cerebral blood flow (CBF), as well as relative CBF (R1), in nondemented older adults.

Methods: Fifty-five nondemented participants (mean age, 78.

Anterior cingulate dopamine turnover and behavior change in Parkinson's disease.

Subtle cognitive and behavioral changes are common in early Parkinson's disease. The cause of these symptoms is probably multifactorial but may in part be related to extra-striatal dopamine levels. 6-[(18) F]-Fluoro-L-dopa (FDOPA) positron emission tomography has been widely used to quantify dopamine metabolism in the brain; the most frequently measured kinetic parameter is the tissue uptake rate constant, Ki.

Memory decline shows stronger associations with estimated spatial patterns of amyloid deposition progression than total amyloid burden.

The development of amyloid imaging compounds has allowed in vivo imaging of amyloid deposition. In this study, we examined the spatial patterns of amyloid deposition throughout the brain using Pittsburgh Compound Blue ((11)C-PiB) positron emission tomography data from the Baltimore Longitudinal Study of Aging. We used a new methodology that allowed us to approximate spatial patterns of the temporal progression of amyloid plaque deposition from cross-sectional data.

Effect of complement CR1 on brain amyloid burden during aging and its modification by APOE genotype.

Background: The rs3818361 single nucleotide polymorphism in complement component (3b/4b) receptor-1 (CR1) is associated with increased risk of Alzheimer's disease (AD). Although this novel variant is associated with a small effect size and is unlikely to be useful as a predictor of AD risk, it might provide insights into AD pathogenesis. We examined the association between rs3818361 and brain amyloid deposition in nondemented older individuals.

Correspondence between in vivo (11)C-PiB-PET amyloid imaging and postmortem, region-matched assessment of plaques.

The definitive Alzheimer's disease (AD) diagnosis requires postmortem confirmation of neuropathological hallmarks-amyloid-β (Aβ) plaques and neurofibrillary tangles (NFTs). The advent of radiotracers for amyloid imaging presents an opportunity to investigate amyloid deposition in vivo. The (11)C-Pittsburgh compound-B (PiB)-PET ligand remains the most widely studied to date; however, regional variations in (11)C-PiB binding and the extent of agreement with neuropathological assessment have not been thoroughly investigated.

Patterns of regional cerebral blood flow associated with low hemoglobin in the Baltimore Longitudinal Study of Aging.

Background: Anemia has been associated with elevated cerebral blood flow (CBF) in animal models and certain clinical conditions (eg, renal disease), but whether hemoglobin level variations across a relatively normal range are associated with local or diffuse CBF changes is unclear. We investigated whether lower hemoglobin is associated with regional increases in relative CBF in older individuals, and if these increases occur in watershed regions.

Methods: Seventy-four older nondemented adults underwent serial (15)O water positron emission tomography scans.

Baseline cardiovascular risk predicts subsequent changes in resting brain function.

Background And Purpose: The Framingham Heart Study group cardiovascular disease risk profile (FCRP) score was used to assess the relationship between baseline cardiovascular risk and subsequent changes in resting state cerebral blood flow (CBF) in cognitively normal older participants from the Baltimore Longitudinal Study of Aging.

Methods: Ninty-seven cognitively normal participants underwent annual resting-state positron emission tomography scans at baseline and over a period of up to 8 years (mean interval, 7.4 years).

Relative equilibrium plot improves graphical analysis and allows bias correction of standardized uptake value ratio in quantitative 11C-PiB PET studies.

Unlabelled: Both the standardized uptake value ratio (SUVR) and the Logan plot result in biased distribution volume ratios (DVRs) in ligand-receptor dynamic PET studies. The objective of this study was to use a recently developed relative equilibrium-based graphical (RE) plot method to improve and simplify the 2 commonly used methods for quantification of (11)C-Pittsburgh compound B ((11)C-PiB) PET.

Methods: The overestimation of DVR in SUVR was analyzed theoretically using the Logan and the RE plots.

Longitudinal patterns of β-amyloid deposition in nondemented older adults.

Background: High levels of β-amyloid (Aβ) characterize Alzheimer disease.

Objective: To investigate whether longitudinal changes in Aβ deposition can be detected in vivo in older adults without dementia (hereafter referred to as nondemented).

Design: Prospective study.

Amyloid imaging and memory change for prediction of cognitive impairment.

PET radiotracers for in vivo measurement of β-amyloid (Aβ) deposition throughout the brain are contributing to early detection of the neuropathology associated with Alzheimer's disease and enhancing prediction of individuals most likely to develop cognitive impairment and dementia. However, the fact that 30 to 50% of cognitively normal older adults have varying but detectable levels of Aβ poses challenges and opportunities in using amyloid imaging in research and clinical applications. In this review, we summarize studies of the relationship between Aβ burden and cognitive status in impaired and unimpaired individuals and the relationship between Aβ burden and cognitive function.

In vivo fibrillar beta-amyloid detected using [11C]PiB positron emission tomography and neuropathologic assessment in older adults.

Background: In demented older adults, in vivo amyloid imaging shows agreement with diagnostic neuropathologic assessment of β-amyloid (Aβ). However, the extent of agreement in nondemented older adults remains unclear.

Objective: To compare Aβ quantified using in vivo carbon 11-labeled Pittsburgh Compound B positron emission tomography and postmortem neuropathologic assessment of Aβ in older adults.

Proteome-based plasma markers of brain amyloid-β deposition in non-demented older individuals.

Blood-based markers reflecting core pathological features of Alzheimer's disease (AD) in pre-symptomatic individuals are likely to accelerate the development of disease-modifying treatments. Our aim was to discover plasma proteins associated with brain amyloid-β (Aβ) burden in non-demented older individuals. We performed discovery-phase experiments using two dimensional gel electrophoresis (2DGE) and mass spectrometry-based proteomic analysis of plasma in combination with 11C-PiB PET imaging of the brain in samples collected 10 years prior to the PET scans.

Intima-media thickness and regional cerebral blood flow in older adults.

Background And Purpose: The relationship between the thickness of the carotid intima (IMT) and brain function remains unclear in those without clinical manifestations of cerebrovascular disease. Understanding the neural correlates of this vascular measure is important in view of emerging evidence linking poorer cognitive performance with increased IMT in individuals without clinical cerebrovascular disease.

Methods: Seventy-three participants in the Baltimore Longitudinal Study of Aging (70.

Longitudinal cerebral blood flow and amyloid deposition: an emerging pattern?

Unlabelled: Although cerebral amyloid deposition may precede cognitive impairment by decades, the relationship between amyloid deposition and longitudinal change in neuronal function has not, to our knowledge, been studied. The aim of this article was to determine whether individuals without dementia with high and low amyloid burden show different patterns of longitudinal regional cerebral blood flow (rCBF) changes in the years preceding measurement of amyloid deposition.

Methods: Twenty-eight participants without dementia (mean age+/-SD, 82.

Does asymmetric basal ganglia or thalamic activation aid in seizure foci lateralization on ictal SPECT studies?

Unlabelled: Basal ganglia or thalamic activation has been reported in ictal SPECT studies of patients with intractable epilepsy. We hypothesized that lateralization of activation of these subcortical structures may aid in the lateralization of seizure foci in patients in whom the cortical focus is subtle or equivocal.

Methods: This was a retrospective analysis of 72 ictal (99m)Tc-ethylcysteinate dimer SPECT studies in 43 patients with intractable epilepsy in whom seizure laterality could be eventually determined.