| 1. |
- Dyrby, Tim B, et al.
(författare)
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Segmentation of age-related white matter changes in a clinical multi-center study.
- 2008
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119. ; 41:2, s. 335-45
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Tidskriftsartikel (refereegranskat)abstract
- Age-related white matter changes (WMC) are thought to be a marker of vascular pathology, and have been associated with motor and cognitive deficits. In the present study, an optimized artificial neural network was used as an automatic segmentation method to produce probabilistic maps of WMC in a clinical multi-center study. The neural network uses information from T1- and T2-weighted and fluid attenuation inversion recovery (FLAIR) magnetic resonance (MR) scans, neighboring voxels and spatial location. Generalizability of the neural network was optimized by including the Optimal Brain Damage (OBD) pruning method in the training stage. Six optimized neural networks were produced to investigate the impact of different input information on WMC segmentation. The automatic segmentation method was applied to MR scans of 362 non-demented elderly subjects from 11 centers in the European multi-center study Leukoaraiosis And Disability (LADIS). Semi-manually delineated WMC were used for validating the segmentation produced by the neural networks. The neural network segmentation demonstrated high consistency between subjects and centers, making it a promising technique for large studies. For WMC volumes less than 10 ml, an increasing discrepancy between semi-manual and neural network segmentation was observed using the similarity index (SI) measure. The use of all three image modalities significantly improved cross-center generalizability compared to neural networks using the FLAIR image only. Expert knowledge not available to the neural networks was a minor source of discrepancy, while variation in MR scan quality constituted the largest source of error.
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| 2. |
- Gouw, Alida A, et al.
(författare)
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On the etiology of incident brain lacunes: longitudinal observations from the LADIS study.
- 2008
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Ingår i: Stroke; a journal of cerebral circulation. - 1524-4628. ; 39:11, s. 3083-5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: We investigated regional differences in MRI characteristics and risk factor profiles of incident lacunes over a 3-year period. METHODS: Baseline and 3-year follow-up MRI were collected within the LADIS study (n=358). Incident lacunes were characterized with respect to brain region, their appearance within pre-existent white matter hyperintensities (WMH), surrounding WMH size, and risk factors. RESULTS: 106 incident lacunes were observed in 62 patients (58 subcortical white matter [WM], 35 basal ganglia, and 13 infratentorial). Incident subcortical WM lacunes occurred more often within preexisting WMH (P=0.01) and were mostly accompanied by new and expanded WMH (P<0.001), compared to incident basal ganglia and infratentorial lacunes. Risk factors for incident subcortical WM lacunes were history of hypertension and stroke, whereas atrial fibrillation predicted incident basal ganglia/infratentorial lacunes. CONCLUSIONS: Differences in relation to WMH and risk factor profiles may suggest that incident lacunes in the subcortical WM have a different pathogenesis than those in the basal ganglia and infratentorial region.
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| 3. |
- Gouw, Alida A, et al.
(författare)
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Progression of white matter hyperintensities and incidence of new lacunes over a 3-year period: the Leukoaraiosis and Disability study.
- 2008
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Ingår i: Stroke; a journal of cerebral circulation. - 1524-4628. ; 39:5, s. 1414-20
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: We studied the natural course of white matter hyperintensities (WMH) and lacunes, the main MRI representatives of small vessel disease, over time and evaluated possible predictors for their development. METHODS: Baseline and repeat MRI (3-year follow-up) were collected within the multicenter, multinational Leukoaraiosis and Disability study (n=396). Baseline WMH were scored on MRI by the Fazekas scale and the Scheltens scale. WMH progression was assessed using the modified Rotterdam Progression scale (absence/presence of progression in 9 brain regions). Baseline and new lacunes were counted per region. WMH and lacunes at baseline and vascular risk factors were evaluated as predictors of WMH progression and new lacunes. RESULTS: WMH progressed (mean+/-SD=1.9+/-1.8) mostly in the subcortical white matter, where WMH was also most prevalent at baseline. The majority of new lacunes, which were found in 19% of the subjects (maximum=9), also appeared in the subcortical white matter, mainly of the frontal lobes, whereas most baseline lacunes were located in the basal ganglia. Baseline WMH and lacunes predicted both WMH progression and new lacunes. Furthermore, previous stroke, diabetes, and blood glucose were risk factors for WMH progression. Male sex, hypertension, systolic blood pressure, previous stroke, body mass index, high-density lipoprotein, and triglyceride levels were risk factors for new lacunes. CONCLUSIONS: WMH and lacunes progressed over time, predominantly in the subcortical white matter. Progression was observed especially in subjects with considerable WMH and lacunes at baseline. Moreover, the presence of vascular risk factors at baseline predicted WMH progression and new lacunes over a 3-year period.
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| 4. |
- Poggesi, Anna, et al.
(författare)
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Urinary complaints in nondisabled elderly people with age-related white matter changes: the Leukoaraiosis And DISability (LADIS) Study.
- 2008
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Ingår i: Journal of the American Geriatrics Society. - : Wiley. - 1532-5415 .- 0002-8614. ; 56:9, s. 1638-43
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate, in a cohort of nondisabled elderly people, the association between urinary complaints and severity of age-related white matter changes (ARWMC). DESIGN: Cross-sectional data analysis from a longitudinal multinational study. SETTING: The Leukoaraiosis And DISability Study, assessing ARWMC as an independent predictor of the transition from functional autonomy to disability in elderly subjects. PARTICIPANTS: Six hundred thirty-nine subjects (288 men, 351 women, mean age 74.1+/-5.0) with magnetic resonance imaging (MRI)-detected ARWMC of different severity. MEASUREMENTS: ARWMC severity was graded on MRI as mild, moderate, and severe (Fazekas scale). MRI assessment also included ARWMC volumetric analysis and the count of infarcts. Urinary complaints (nocturia, urinary frequency, urgency, incontinence) were recorded based on subjects' answers to four questions. RESULTS: In comparing the three ARWMC severity groups, there was a significant difference only in prevalence of urgency, with 16% of subjects in the mild severity group, 17% in the moderate severity group, and 25% in the severe group (P=.03). Adjusting for age, sex, lacunar and nonlacunar infarcts, diabetes mellitus, and use of diuretics, severe ARWMC retained an independent effect in the association with urinary urgency (odds ratio=1.74, 95% confidence interval=1.04-2.90, severe vs mild group). Subjects with urinary urgency also had higher ARWMC volumes (25.2, vs 20.4 mm(3) in those without urinary urgency; P<.001). Urgency was confirmed to be associated with the severe degree of ARWMC, irrespective of complaints of memory, gait disturbances, or history of depression. CONCLUSION: In a cohort of nondisabled elderly people, severe ARWMC were associated with urinary urgency, independent of other potential confounders and vascular lesions of the brain.
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