24 research outputs found

    Reduced parenchymal cerebral blood flow is associated with greater progression of brain atrophy: the SMART-MR study

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    Global cerebral hypoperfusion may be involved in the aetiology of brain atrophy; however, long-term longitudinal studies on this relationship are lacking. We examined whether reduced cerebral blood flow was associated with greater progression of brain atrophy. Data of 1165 patients (61 +/- 10 years) from the SMART-MR study, a prospective cohort study of patients with arterial disease, were used of whom 689 participated after 4 years and 297 again after 12 years. Attrition was substantial. Total brain volume and total cerebral blood flow were obtained from magnetic resonance imaging scans and expressed as brain parenchymal fraction (BPF) and parenchymal cerebral blood flow (pCBF). Mean decrease in BPF per year was 0.22% total intracranial volume (95% CI: -0.23 to -0.21). Mean decrease in pCBF per year was 0.24 ml/min per 100 ml brain volume (95% CI: -0.29 to -0.20). Using linear mixed models, lower pCBF at baseline was associated with a greater decrease in BPF over time (p = 0.01). Lower baseline BPF, however, was not associated with a greater decrease in pCBF (p = 0.43). These findings indicate that reduced cerebral blood flow is associated with greater progression of brain atrophy and provide further support for a role of cerebral blood flow in the process of neurodegeneration.Neuro Imaging Researc

    Microinfarcts in the Deep Gray Matter on 7T MRI: Risk Factors, MRI Correlates, and Relation to Cognitive Functioning-The SMART-MR Study

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    BACKGROUND AND PURPOSE: The clinical relevance of cortical microinfarcts has recently been established; however, studies on microinfarcts in the deep gray matter are lacking. We examined the risk factors and MR imaging correlates of microinfarcts in the deep gray matter on 7T MR imaging and their relation to cognitive functioning.\MATERIALS AND METHODS: Within the Second Manifestations of ARTerial disease?Magnetic Resonance (SMART-MR) study, 213 patients (mean age, 68 [SD, 8]?years) had a risk-factor assessment, 7T and 1.5T brain MR imaging, and a cognitive examination. Microinfarcts on 7T MR imaging were defined as lesions of < 5 mm. Regression models were used to examine the age-adjusted associations among risk factors, MR imaging markers, and microinfarcts. Cognitive function was summarized as composite and domain-specific z scores. RESULTS: A total of 47 microinfarcts were found in 28 patients (13%), most commonly in the thalamus. Older age, history of stroke, hypertension, and intima-media thickness were associated with microinfarcts. On 1.5T MR imaging, cerebellar infarcts (relative risk = 2.75; 95% CI, 1.4?5.33) and lacunes in the white (relative risk = 3.28; 95% CI, 3.28?6.04) and deep gray matter (relative risk?= 3.06; 95% CI, 1.75?5.35) were associated with microinfarcts, and on 7T MR imaging cortical microinfarcts (relative risk = 2.33; 95% CI, 1.32?4.13). Microinfarcts were also associated with poorer global cognitive functioning (mean difference in the global z score between patients with multiple microinfarcts versus none = ?0.97; 95% CI, ?1.66 to ?0.28, P = .006) and across all cognitive domains. CONCLUSIONS: Microinfarcts in the deep gray matter on 7T MR imaging were associated with worse cognitive functioning and risk factors and MR imaging markers of small-vessel and large-vessel disease. Our findings suggest that microinfarcts in the deep gray matter may represent a novel imaging marker of vascular brain injury

    Intracranial Atherosclerotic Burden on 7T MRI Is Associated with Markers of Extracranial Atherosclerosis : The SMART-MR Study

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    BACKGROUND AND PURPOSE: Intracranial atherosclerosis, a major risk factor for ischemic stroke, is thought to have different atherogenic mechanisms than extracranial atherosclerosis. Studies investigating their relationship in vivo are sparse and report inconsistent results. We studied the relationship between intracranial atherosclerosis and extracranial atherosclerosis in a cohort of patients with a history of vascular disease. MATERIALS AND METHODS: Within the Second Manifestations of ARTerial disease-Magnetic Resonance (SMART) study, cross-sectional analyses were performed in 130 patients (mean age, 68 ± 9 years) with a history of vascular disease and with assessable 7T intracranial vessel wall MR imaging data. Intracranial atherosclerosis burden was defined as the number of intracranial vessel wall lesions in the circle of Willis and its major branches. Age- and sex-adjusted unstandardized regression coefficients (b-value) were calculated with intracranial atherosclerosis burden as the dependent variable and extracranial atherosclerosis markers as independent variables. RESULTS: Ninety-six percent of patients had ≥1 vessel wall lesion, with a mean intracranial atherosclerosis burden of 8.5 ± 5.7 lesions. Significant associations were observed between higher intracranial atherosclerosis burden and carotid intima-media thickness (b = 0.53 lesions per +0.1 mm; 95% CI, 0.1-1.0 lesions), 50%-100% carotid stenosis versus no stenosis (b = 6.6 lesions; 95% CI, 2.3-10.9 lesions), ankle-brachial index ≤ 0.9 versus >0.9 (b = 4.9 lesions; 95% CI, 1.7-8.0 lesions), and estimated glomerular filtration rate (b = -0.77 lesions per +10 mL/min; 95% CI, -1.50 to -0.03 lesions). No significant differences in intracranial atherosclerosis burden were found among different categories of vascular disease. CONCLUSIONS: Intracranial atherosclerosis was associated with various extracranial markers of atherosclerosis, not supporting a different etiology

    Low-grade carotid artery stenosis is associated with progression of brain atrophy and cognitive decline. The SMART-MR study

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    Asymptomatic low-grade carotid artery stenosis (LGCS) is a common finding in patients with manifest arterial disease, however its relationship with brain MRI changes and cognitive decline is unclear. We included 902 patients (58 +/- 10 years; 81% male) enrolled in the Second Manifestations of Arterial Disease - Magnetic Resonance (SMART-MR) study without a history of cerebrovascular disease. LGCS was defined as 1-49% stenosis on baseline carotid ultrasound, whereas no LGCS (reference category) was defined as absence of carotid plaque. Brain and white matter hyperintensity (WMH) volumes and cognitive function were measured at baseline and after 4 (n = 480) and 12 years (n = 222) of follow-up. Using linear mixed-effects models, we investigated associations of LGCS with progression of brain atrophy, WMH, and cognitive decline. LGCS was associated with greater progression of global brain atrophy (estimate -0.03; 95%CI, -0.06 to -0.01; p = 0.002), and a greater decline in executive functioning (estimate -0.02; 95%CI, -0.031 to -0.01; p < 0.001) and memory (estimate -0.012; 95%CI, -0.02 to -0.001; p = 0.032), independent of demographics, cardiovascular risk factors, and incident brain infarcts on MRI. No association was observed between LGCS and progression of WMH. Our results indicate that LGCS may represent an early marker of greater future brain atrophy and cognitive decline

    White matter hyperintensity shape is associated with cognitive functioning - the SMART-MR study

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    White matter hyperintensity (WMH) shape has been associated with the severity of the underlying brain pathology, suggesting it is a potential neuroimaging marker of WMH impact on brain function.In 563 patients with vascular disease (58 +/- 10 years), we examined the relationship between WMH volume, shape, and cognitive functioning. WMH volume and shape were automatically determined on 1.5T brain MRI data. Standardized linear regression analyses estimated the association between WMH volume and shape (concavity index, solidity, convexity, fractal dimension, and eccentricity) and memory and executive functioning, adjusted for age, sex, educational level, and reading ability.Larger WMH volumes were associated with lower executive functioning Z-scores ( b (95%-CI):-0.09 (-0.17;-0.01)). Increased shape complexity of periventricular/confluent WMH associated with lower exec-utive functioning (concavity index + 1SD:-0.13 (-0.20;-0.06); solidity-1SD:-0.09 (-0.17;-0.02)) and lower memory function (fractal dimension + 1SD:-0.10 (-0.18;-0.02)). Of note, the association between concav-ity index and executive functioning was independent of WMH volume (-0.12 (-0.19;-0.04)). Our results suggest that WMH shape contains additional information about WMH burden, not other-wise captured by WMH volume.(c) 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/
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