Structural brain imaging in diabetes: A methodological perspective
Department of Neurology/Image Sciences Institute, University Medical Center Utrecht, Q0S.459, P.O. Box 85500, 3508 GA Utrecht, The Netherlands. European Journal of Pharmacology
(Impact Factor: 2.53).
06/2008; 585(1):208-18. DOI: 10.1016/j.ejphar.2007.11.085
Brain imaging provides information on brain anatomy and function and progression of cerebral abnormalities can be monitored. This may provide insight into the aetiology of diabetes related cerebral disorders. This paper focuses on the methods for the assessment of white matter hyperintensities and brain atrophy on structural brain images, mostly magnetic resonance imaging, in diabetes. These methods range from visual rating scales to advanced semi-automated and automated image processing techniques such as volumetry and voxel-based morphometry. The findings of previous imaging studies in diabetes are discussed from a methodological perspective and recommendations for future research are given.
Available from: Junghyun H Lee
- "Reductions in the total brain volume or cortical/subcortical brain volume in T2DM have been indicated by several neuroimaging studies . Modest cerebral atrophy in the T2DM population has been consistently observed [32,35]. Furthermore, a significant association has been found between cerebral atrophy in DM and cognitive impairment, even after the effect of comorbid vascular diseases was adjusted . "
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ABSTRACT: As the prevalence and life expectancy of type 2 diabetes mellitus (T2DM) continue to increase, the importance of effective detection and intervention for the complications of T2DM, especially neurocognitive complications including cognitive dysfunction and dementia, is receiving greater attention. T2DM is thought to influence cognitive function through an as yet unclear mechanism that involves multiple factors such as hyperglycemia, hypoglycemia, and vascular disease. Recent developments in neuroimaging methods have led to the identification of potential neural correlates of T2DM-related neurocognitive changes, which extend from structural to functional and metabolite alterations in the brain. The evidence indicates various changes in the T2DM brain, including global and regional atrophy, white matter hyperintensity, altered functional connectivity, and changes in neurometabolite levels. Continued neuroimaging research is expected to further elucidate the underpinnings of cognitive decline in T2DM and allow better diagnosis and treatment of the condition.
Available from: Caterina Rosano
- "Pulse pressure (the difference between systolic and diastolic blood pressure, which is associated with vessel stiffening and vascular aging) has also been cross-sectionally associated with white matter hyperintensities in older adults . Glucose-related disturbances have also been associated with brain structural changes   . Among lifestyle factors, attention has recently focused on the role of diet and physical activity as well as to social and cognitive engagement in brain aging . "
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ABSTRACT: Maintaining brain health promotes successful aging. The main determinants of brain health are the preservation of cognitive function and remaining free from structural and metabolic abnormalities, including loss of neuronal synapses, atrophy, small vessel disease and focal amyloid deposits visible by neuroimaging. Promising studies indicate that these determinants are to some extent modifiable, even among adults seventy years and older. Converging animal and human evidence further suggests that inflammation is a shared mechanism, contributing to both cognitive decline and abnormalities in brain structure and metabolism. Thus, inflammation may provide a target for intervention. Specifically, circulating inflammatory markers have been associated with declines in cognitive function and worsening of brain structural and metabolic characteristics. Additionally, it has been proposed that older brains are characterized by a sensitization to neuroinflammatory responses, even in the absence of overt disease. This increased propensity to central inflammation may contribute to poor brain health and premature brain aging. Still unknown is whether and how peripheral inflammatory factors directly contribute to decline of brain health. Human research is limited by the challenges of directly measuring neuroinflammation in vivo. This review assesses the role that inflammation may play in the brain changes that often accompany aging, focusing on relationships between peripheral inflammatory markers and brain health among well-functioning, community-dwelling adults seventy years and older. We propose that monitoring and maintaining lower levels of systemic and central inflammation among older adults could help preserve brain health and support successful aging. Hence, we also identify plausible ways and novel experimental study designs of maintaining brain health late in age through interventions that target the immune system.
Available from: David F Tate
- "Magnetic resonance imaging (MRI) based brain volumetry is a valuable technique for identifying subcortical morphometric changes in vivo and determining the regional neurological impact of psychopathology, disease progression, and advancing therapeutic regimens. This approach has been useful for characterizing the effects of dementia (Carmichael et al. 2005, Teipel et al. 2008, Thompson et al. 2001), psychiatric disorders (Csernansky et al. 1998, Hickie et al. 2005, Konarski et al. 2008, Styner et al. 2004), and normal aging (Brickman et al. 2008, Elderkin-Thompson et al. 2008, Walhovd et al. 2005), as well as uncovering regional and global neurological consequences of systemic diseases such as the Human Immunodeficiency Virus (HIV) (Carmichael et al. 2007, Sporer et al. 2005, Stout et al. 1998, Thompson et al. 2005, Thompson et al. 2006), diabetes (Jongen and Biessels 2008, Perantie et al. 2007, Tiehuis et al. 2008, Wessels et al. 2007), and scoliosis (Liu et al. 2008). As techniques in MRI continue to advance, in vivo volumetric measurement will become increasingly valuable in the drive to understand the evolution and progression of injury for CNS disorders as well as typical aging. "
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ABSTRACT: The automated volumetric output of FreeSurfer and Individual Brain Atlases using Statistical Parametric Mapping (IBASPM), two widely used and well published software packages, was examined for accuracy and consistency relative to auto-assisted manual (AAM) tracings (i.e., manual correction of automated output) when measuring the caudate, putamen, amygdala, and hippocampus in the baseline scans of 120 HIV-infected patients (86.7% male, 47.3+/-6.3y.o., mean HIV duration 12.0+/-6.3years) from the NIH-funded HIV Neuroimaging Consortium (HIVNC) cohort. The data was examined for accuracy and consistency relative to auto-assisted manual tracing, and construct validity was assessed by correlating automated and AAM volumetric measures with relevant clinical measures of HIV progression. When results were averaged across all patients in the eight structures examined, FreeSurfer achieved lower absolute volume difference in five, higher sensitivity in seven, and higher spatial overlap in all eight structures. Additionally, FreeSurfer results exhibited less variability in all measures. Output from both methods identified discrepant correlations with clinical measures of HIV progression relative to AAM segmented data. Overall, FreeSurfer proved more effective in the context of subcortical volumetry in HIV-patients, particularly in a multisite cohort study such as this. These findings emphasize that regardless of the automated method used, visual inspection of segmentation output, along with manual correction if necessary, remains critical to ensuring the validity of reported results.
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