73 research outputs found

    Can cartilage loss be detected in knee osteoarthritis (OA) patients with 3–6 months' observation using advanced image analysis of 3T MRI?

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    SummaryPurposePrior investigations of magnetic resonance imaging (MRI) biomarkers of cartilage loss in knee osteoarthritis (OA) suggest that trials of interventions which affect this biomarker with adequate statistical power would require large clinical studies of 1–2 years duration. We hypothesized that smaller, shorter duration, “Proof of Concept” (PoC) studies might be achievable by: (1) selecting a population at high risk of rapid medial tibio-femoral (TF) progression, in conjunction with; (2) high-field MRI (3T), and; (3) using advanced image analysis. The primary outcome was the cartilage thickness in the central medial femur.MethodsMulti-centre, non-randomized, observational cohort study at four sites in the US. Eligible participants were females with knee pain, a body mass index (BMI)≥25kg/m2, symptomatic radiographic evidence of medial TF OA, and varus mal-alignment. The 29 participants had a mean age of 62 years, mean BMI of 36kg/m2, with eight index knees graded as Kellgren–Lawrence (K&L)=2 and 21 as K&L=3. Eligible participants had four MRI scans of one knee: two MRIs (1 week apart) were acquired as a baseline with follow-up MRI at 3 and 6 months. A trained operator, blind to time-point but not subject, manually segmented the cartilage from the Dual Echo Steady State water excitation MR images. Anatomically corresponding regions of interest were identified on each image by using a three-dimensional statistical shape model of the endosteal bone surface, and the cartilage thickness (with areas denuded of cartilage included as having zero thickness – ThCtAB) within each region was calculated. The percentage change from baseline at 3 and 6 months was assessed using a log-scale analysis of variance (ANOVA) model including baseline as a covariate. The primary outcome was the change in cartilage thickness within the aspect of central medial femoral condyle exposed within the meniscal window (w) during articulation, neglecting cartilage edges [nuclear (n)] (nwcMF·ThCtAB), with changes in other regions considered as secondary endpoints.ResultsAnatomical mal-alignment ranged from −1.9° to 6.3°, with mean 0.9°. With one exception, no changes in ThCtAB were detected at the 5% level for any of the regions of interest on the TF joint at 3 or 6 months of follow-up. The change in the primary variable (nwcMF·ThCtAB) from (mean) baseline at 3 months from the log-scale ANOVA model was −2.1% [95% confidence interval (CI) (−4.4%, +0.2%)]. The change over 6 months was 0.0% [95% CI (−2.7%, +2.8%)]. The 95% CI for the change from baseline did not include zero for the cartilage thickness within the meniscal window of the lateral tibia (wLT·ThCtAB) at 6 month follow-up (−1.5%, 95% CI [−2.9, −0.2]), but was not significant at the 5% level after correction for multiple comparisons.ConclusionsThe small inconsistent compartment changes, and the relatively high variabilities in cartilage thickness changes seen over time in this study, provide no additional confidence for a 3- or 6-month PoC study using a patient population selected on the basis of risk for rapid progression with the MRI acquisition and analyses employed

    Race and sex differences in willingness to undergo total joint replacement: The Johnston County Osteoarthritis Project

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    Objective Using data from the community-based Johnston County Osteoarthritis Project, we examined race and sex variations in willingness to undergo, and perceptions regarding, total joint replacement (TJR). Methods Analyses were conducted for the total sample who participated in a followup measurement period from 2006-2010 (n = 1,522) and a subsample with symptomatic hip and/or knee osteoarthritis (sOA; n = 445). Participants indicated how willing they would be to have TJR (hip or knee) if their doctor recommended it; responses were categorized as "definitely" or "probably" willing versus "unsure," "probably not," or "definitely not" willing, or "don't know." Participants answered 7 questions regarding perceptions of TJR outcomes. Multivariable logistic regression models of willingness included participant characteristics (including socioeconomic status) and TJR perception variables that were associated with willingness at the P < 0.1 level in bivariate analyses. Results African Americans had lower odds of willingness to undergo TJR than whites in the total sample (adjusted odds ratio [OR] 0.47 [95% confidence interval (95% CI) 0.31-0.72]) and the sOA subsample (adjusted OR 0.42 [95% CI 0.25-0.69]). There were no sex differences in willingness. African Americans expected poorer TJR outcomes than whites, but sex differences were minimal; perceptions of TJR outcomes were not significantly associated with willingness. Conclusion In this community sample, race differences in TJR willingness and perceptions were substantial, but sex differences were small. Perceptions of TJR did not appear to affect willingness or explain race differences in willingness

    Probabilistic reasoning from correlated objective data

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    SIGLEAvailable from British Library Document Supply Centre-DSC:DXN005492 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    INVERTER: INtegrated variable number tandem rEpeat findeR

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    10.1007/978-3-642-16750-8_14Communications in Computer and Information Science115 CCIS151-16

    A New Measure for the Accuracy of a Bayesian Network

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