The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Monique M B Breteler - One of the best experts on this subject based on the ideXlab platform.
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progression of cerebral small vessel disease in relation to risk factors and cognitive consequences rotterdam scan study
Stroke, 2008Co-Authors: Ewoud J Van Dijk, N D Prins, Henri A Vrooman, Albert Hofman, Peter J Koudstaal, Monique M B BretelerAbstract:Background and Purpose— Cerebral white matter Lesions and lacunar infarcts are small vessel disease-related Lesions, which are associated with cognitive decline and dementia. We aimed to assess the relationship between risk factors, effect modifiers, and progression of these Lesions. Furthermore, we studied the cognitive consequences of Lesion progression. Methods— Six hundred sixty-eight people, aged 60 to 90 years, underwent repeated MRI scanning and neuropsychological testing within 3-year follow-up. We rated incident lacunar infarcts and change in periventricular and subcortical white matter Lesion severity with a semiquantitative scale. We assessed the relationships between age, sex, baseline Lesion load, risk factors, Lesion progression, and change in cognitive function by multivariate regression analyses and additional stratified analyses. Results— Baseline Lesion load, higher age, high blood pressure, and current smoking were independently associated with progression of white matter Lesions. Women...
Robert W. Wissler - One of the best experts on this subject based on the ideXlab platform.
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a definition of advanced types of atherosclerotic Lesions and a histological classification of atherosclerosis a report from the committee on vascular Lesions of the council on arteriosclerosis american heart association
Circulation, 1995Co-Authors: H C Stary, A B Chandler, W D Wagner, C. J. Schwartz, Seymour Glagov, Michael E Rosenfeld, William Insull, R E Dinsmore, Valentin Fuster, Robert W. WisslerAbstract:This report is the continuation of two earlier reports that defined human arterial intima and precursors of advanced atherosclerotic Lesions in humans. This report describes the characteristic components and pathogenic mechanisms of the various advanced atherosclerotic Lesions. These, with the earlier definitions of precursor Lesions, led to the histological classification of human atherosclerotic Lesions found in the second part of this report. The Committee on Vascular Lesions also attempted to correlate the appearance of Lesions noted in clinical imaging studies with histological Lesion types and corresponding clinical syndromes. In the histological classification, Lesions are designated by Roman numerals, which indicate the usual sequence of Lesions progression. The initial (type I) Lesion contains enough atherogenic lipoprotein to elicit an increase in macrophages and formation of scattered macrophage foam cells. As in subsequent Lesion types, the changes are more marked in locations of arteries with adaptive intimal thickening. (Adaptive thickenings, which are present at constant locations in everyone from birth, do not obstruct the lumen and represent adaptations to local mechanical forces). Type II Lesions consist primarily of layers of macrophage foam cells and lipid-laden smooth muscle cells and include Lesions grossly designated as fatty streaks. Type III is the intermediate stage between type II and type IV (atheroma, a Lesion that is potentially symptom-producing). In addition to the lipid-laden cells of type II, type III Lesions contain scattered collections of extracellular lipid droplets and particles that disrupt the coherence of some intimal smooth muscle cells. This extracellular lipid is the immediate precursor of the larger, confluent, and more disruptive core of extracellular lipid that characterizes type IV Lesions. Beginning around the fourth decade of life, Lesions that usually have a lipid core may also contain thick layers of fibrous connective tissue (type V Lesion) and/or fissure, hematoma, and thrombus (type VI Lesion). Some type V Lesions are largely calcified (type Vb), and some consist mainly of fibrous connective tissue and little or no accumulated lipid or calcium (type Vc).
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a definition of initial fatty streak and intermediate Lesions of atherosclerosis a report from the committee on vascular Lesions of the council on arteriosclerosis american heart association
Circulation, 1994Co-Authors: H C Stary, A B Chandler, S A Schaffer, W D Wagner, C. J. Schwartz, John R Guyton, Seymour Glagov, Michael E Rosenfeld, William Insull, Robert W. WisslerAbstract:The compositions of Lesion types that precede and that may initiate the development of advanced atherosclerotic Lesions are described and the possible mechanisms of their development are reviewed. While advanced Lesions involve disorganization of the intima and deformity of the artery, such changes are absent or minimal in their precursors. Advanced Lesions are either overtly clinical or they predispose to the complications that cause ischemic episodes; precursors are silent and do not lead directly to complications. The precursors are arranged in a temporal sequence of three characteristic Lesion types. Types I and II are generally the only Lesion types found in children, although they may also occur in adults. Type I Lesions represent the very initial changes and are recognized as an increase in the number of intimal macrophages and the appearance of macrophages filled with lipid droplets (foam cells). Type II Lesions include the fatty streak Lesion, the first grossly visible Lesion, and are characteriz...
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a definition of initial fatty streak and intermediate Lesions of atherosclerosis a report from the committee on vascular Lesions of the council on arteriosclerosis american heart association
Arteriosclerosis Thrombosis and Vascular Biology, 1994Co-Authors: H C Stary, A B Chandler, S A Schaffer, W D Wagner, C. J. Schwartz, John R Guyton, Seymour Glagov, Michael E Rosenfeld, William Insull, Robert W. WisslerAbstract:The compositions of Lesion types that precede and that may initiate the development of advanced atherosclerotic Lesions are described and the possible mechanisms of their development are reviewed. While advanced Lesions involve disorganization of the intima and deformity of the artery, such changes are absent or minimal in their precursors. Advanced Lesions are either overtly clinical or they predispose to the complications that cause ischemic episodes; precursors are silent and do not lead directly to complications. The precursors are arranged in a temporal sequence of three characteristic Lesion types. Types I and II are generally the only Lesion types found in children, although they may also occur in adults. Type I Lesions represent the very initial changes and are recognized as an increase in the number of intimal macrophages and the appearance of macrophages filled with lipid droplets (foam cells). Type II Lesions include the fatty streak Lesion, the first grossly visible Lesion, and are characterized by layers of macrophage foam cells and lipid droplets within intimal smooth muscle cells and minimal coarse-grained particles and heterogeneous droplets of extracellular lipid. Type III (intermediate) Lesions are the morphological and chemical bridge between type II and advanced Lesions. Type III Lesions appear in some adaptive intimal thickenings (progression-prone locations) in young adults and are characterized by pools of extracellular lipid in addition to all the components of type II Lesions.
Al Reaves - One of the best experts on this subject based on the ideXlab platform.
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effect of Lesion size visual acuity and Lesion composition on visual acuity change with and without verteporfin therapy for choroidal neovascularization secondary to age related macular degeneration tap and vip report no 1
American Journal of Ophthalmology, 2003Co-Authors: Kevin J Blinder, S Bradley, N M Bressler, Susan B Bressler, G Donati, Ugo Menchini, Joan W Miller, Michael J Potter, Constantin J Pournaras, Al ReavesAbstract:PURPOSE: To determine whether differences in baseline Lesion size and visual acuity might explain differing results found in three different Lesion compositions (predominantly classic, minimally classic, and occult with no classic) among three placebo-controlled, randomized clinical trials evaluating photodynamic therapy with verteporfin (Visudyne, Novartis AG), also termed verteporfin therapy, in patients with subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration (AMD). METHODS: Exploratory analyses were conducted in patients with predominantly classic or minimally classic Lesions at enrollment in the Treatment of AMD with Photodynamic Therapy (TAP) Investigation and in AMD patients with occult with no classic CNV in the Verteporfin In Photodynamic Therapy (VIP) Trial. Baseline characteristics of patients among these three Lesion compositions were compared. In addition, multiple linear regression modeling was used to explore the effect of baseline Lesion size, visual acuity, and Lesion composition on mean change in visual acuity from baseline to 24 months. RESULTS: At baseline, the mean size of predominantly classic Lesions (3.4 disk areas) was smaller than that of minimally classic (4.7 disk areas) and occult with no classic Lesions (4.3 disk areas). In the multiple linear regression model of individual Lesion compositions, there was a significant treatment-by-Lesion-size interaction for minimally classic and occult with no classic Lesions, but not for predominantly classic Lesions. Interaction between treatment and baseline visual acuity was not significant for any Lesion composition. Small verteporfin-treated Lesions lost less vision than large verteporfin-treated Lesions in each Lesion composition. In the multiple linear regression model that included all Lesion compositions, Lesion size was a more significant predictive factor for the magnitude of treatment benefit than either Lesion composition or visual acuity. Smaller (4.0 disk areas or less) minimally classic and occult with no classic Lesions had similar visual acuity outcomes to those observed in predominantly classic Lesions. CONCLUSIONS: Based on exploratory analyses, Lesion size in the TAP Investigation and VIP Trial was an important predictor of the magnitude of treatment benefit with verteporfin therapy in occult with no classic and minimally classic Lesion compositions. In patients with AMD, treating smaller rather than larger neovascular Lesions, regardless of Lesion composition, likely will result in a better level of visual acuity.
Claudia A M Wheelerkingshott - One of the best experts on this subject based on the ideXlab platform.
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reducing the impact of white matter Lesions on automated measures of brain gray and white matter volumes
Journal of Magnetic Resonance Imaging, 2010Co-Authors: D T Chard, J S Jackson, David H Miller, Claudia A M WheelerkingshottAbstract:Purpose: To develop an automated Lesion-filling technique (LEAP; Lesion Automated Preprocessing) that would reduce Lesion-associated brain tissue segmentation bias (which is known to affect automated brain gray [GM] and white matter [WM] tissue segmentations in people who have multiple sclerosis), and a WM Lesion simulation tool with which to Lest it.Materials and Methods: Simulated Lesions with differing volumes and signal intensities were added to volumetric brain images from three healthy subjects and then automatically filled with values approximating normal WM. We tested the effects of simulated Lesions and Lesion-filling correction with LEAP on SPM-derived tissue volume estimates.Results: GM and WM tissue volume estimates were affected by the presence of WM Lesions. With simulated Lesion volumes of 15 mL at 70% of normal WM intensity, the effect was to increase GM fractional (relative to intracranial) volumes by approximate to 2.3%, and reduce WM fractions by approximate to 3.6%. Lesion filling reduced these errors toConclusion: The effect of WM Lesions on automated GM and WM volume measures may be considerable and thereby obscure real disease-mediated volume changes. Lesion filling with values approximating normal WM enables more accurate GM and WM volume measures and should be applicable to structural scans independently of the software used for the segmentation.
Bernhard Hemmer - One of the best experts on this subject based on the ideXlab platform.
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an automated tool for detection of flair hyperintense white matter Lesions in multiple sclerosis
NeuroImage, 2012Co-Authors: Paul Schmidt, Christian Gaser, Milan Arsic, Dorothea Buck, Annette Forschler, Achim Berthele, Muna Hoshi, Volker Schmid, Claus Zimmer, Bernhard HemmerAbstract:In Multiple Sclerosis (MS), detection of T2-hyperintense white matter (WM) Lesions on magnetic resonance imaging (MRI) has become a crucial criterion for diagnosis and predicting prognosis in early disease. Automated Lesion detection is not only desirable with regard to time and cost effectiveness but also constitutes a prerequisite to minimize user bias. Here, we developed and evaluated an algorithm for automated Lesion detection requiring a three-dimensional (3D) gradient echo (GRE) T1-weighted and a FLAIR image at 3 Tesla (T). Our tool determines the three tissue classes of gray matter (GM) and WM as well as cerebrospinal fluid (CSF) from the T1-weighted image, and, then, the FLAIR intensity distribution of each tissue class in order to detect outliers, which are interpreted as Lesion beliefs. Next, a conservative Lesion belief is expanded toward a liberal Lesion belief. To this end, neighboring voxels are analyzed and assigned to Lesions under certain conditions. This is done iteratively until no further voxels are assigned to Lesions. Herein, the likelihood of belonging to WM or GM is weighed against the likelihood of belonging to Lesions. We evaluated our algorithm in 53 MS patients with different Lesion volumes, in 10 patients with posterior fossa Lesions, and 18 control subjects that were all scanned at the same 3T scanner (Achieva, Philips, Netherlands). We found good agreement with Lesions determined by manual tracing (R2 values of over 0.93 independent of FLAIR slice thickness up to 6 mm). These results require validation with data from other protocols based on a conventional FLAIR sequence and a 3D GRE T1-weighted sequence. Yet, we believe that our tool allows fast and reliable segmentation of FLAIR-hyperintense Lesions, which might simplify the quantification of Lesions in basic research and even clinical trials.
