53 research outputs found

    PET/CT Scanner and Bone Marrow Biopsy in Detection of Bone Marrow Involvement in Diffuse Large B-Cell Lymphoma.

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    Evaluation of bone marrow involvement (BMI) is paramount in diffuse large B-cell lymphoma (DLBCL) for prognostic and therapeutic reasons. PET/CT scanner (PET) is now a routine examination for the staging of DLBCL with prognostic and therapeutic implications. This study evaluates the role of PET for detecting marrow involvement compared to bone marrow biopsy (BMB). This monocentric study included 54 patients diagnosed with DLBCL between 2009 and 2013 and who had FDG PET/CT in a pre-treatment setting. A correlation analysis of the detection of BMI by PET and BMB was performed. A prognostic evaluation of BMI by BMB and/or PET/CT and correlation with an overall 2-year survival were analyzed. PET was more sensitive for the detection of BMI than BMB (92.3% vs. 38.5%). It can be considered a discriminatory Pre-BMB test with a negative predictive value of 97.6%. In addition, BMI by PET had a prognostic value with strong correlation with progression-free survival (PFS) (HR = 3.81; p = 0.013) and overall survival (OS) (HR = 4.12; p = 0.03) while the BMB had not. PET shows superior performance to the BMB for the detection of marrow involvement in DLBCL. It may be considered as the first line examination of bone marrow instead of the biopsy

    Signature of survival: a <sup>18</sup>F-FDG PET based whole-liver radiomic analysis predicts survival after <sup>90</sup>Y-TARE for hepatocellular carcinoma.

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    To generate a predictive whole-liver radiomics scoring system for progression-free survival (PFS) and overall survival (OS) in patients undergoing transarterial radioembolization using Yttrium-90 ( &lt;sup&gt;90&lt;/sup&gt; Y-TARE) for unresectable hepatocellular carcinoma (uHCC). The generated pPET-RadScores were significantly correlated with survival for PFS (median of 11.4 mo [95% confidence interval CI: 6.3-16.5 mo] in low-risk group [PFS-pPET-RadScore &lt; 0.09] vs. 4.0 mo [95% CI: 2.3-5.7 mo] in high-risk group [PFS-pPET-RadScore &gt; 0.09]; &lt;i&gt;P&lt;/i&gt; = 0.0004) and OS (median of 20.3 mo [95% CI: 5.7-35 mo] in low-risk group [OS-pPET-RadScore &lt; 0.11] vs. 7.7 mo [95% CI: 6.0-9.5 mo] in high-risk group [OS-pPET-RadScore &gt; 0.11]; &lt;i&gt;P&lt;/i&gt; = 0.007). The multivariate analysis confirmed PFS-pPET-RadScore ( &lt;i&gt;P&lt;/i&gt; = 0.006) and OS-pPET-RadScore ( &lt;i&gt;P&lt;/i&gt; = 0.001) as independent negative predictors. Pretreatment &lt;sup&gt;18&lt;/sup&gt; F-FDG PET whole-liver radiomics signature appears as an independent negative predictor for PFS and OS in patients undergoing &lt;sup&gt;90&lt;/sup&gt; Y-TARE for uHCC. Pretreatment &lt;sup&gt;18&lt;/sup&gt; F-FDG PET of 47 consecutive patients undergoing &lt;sup&gt;90&lt;/sup&gt; Y-TARE for uHCC (31 resin spheres, 16 glass spheres) were retrospectively analyzed. For each patient, based on PET radiomics signature from whole-liver semi-automatic segmentation, PFS and OS predictive PET-radiomics scores (pPET-RadScores) were obtained using LASSO Cox regression. Using X-tile software, the optimal score to predict PFS (PFS-pPET-RadScore) and OS (OS-pPET-RadScore) served as cutoff to separate high and low-risk patients. Survival curves were estimated using the Kaplan-Meier method. The prognostic value of PFS and OS-pPET-RadScore, Barcelona-Clinic Liver Cancer staging system and serum alpha-fetoprotein level was analyzed to predict PFS and OS in multivariate analysis

    Automatic Head and Neck Tumor segmentation and outcome prediction relying on FDG-PET/CT images: Findings from the second edition of the HECKTOR challenge.

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    By focusing on metabolic and morphological tissue properties respectively, FluoroDeoxyGlucose (FDG)-Positron Emission Tomography (PET) and Computed Tomography (CT) modalities include complementary and synergistic information for cancerous lesion delineation and characterization (e.g. for outcome prediction), in addition to usual clinical variables. This is especially true in Head and Neck Cancer (HNC). The goal of the HEad and neCK TumOR segmentation and outcome prediction (HECKTOR) challenge was to develop and compare modern image analysis methods to best extract and leverage this information automatically. We present here the post-analysis of HECKTOR 2nd edition, at the 24th International Conference on Medical Image Computing and Computer-Assisted Intervention (MICCAI) 2021. The scope of the challenge was substantially expanded compared to the first edition, by providing a larger population (adding patients from a new clinical center) and proposing an additional task to the challengers, namely the prediction of Progression-Free Survival (PFS). To this end, the participants were given access to a training set of 224 cases from 5 different centers, each with a pre-treatment FDG-PET/CT scan and clinical variables. Their methods were subsequently evaluated on a held-out test set of 101 cases from two centers. For the segmentation task (Task 1), the ranking was based on a Borda counting of their ranks according to two metrics: mean Dice Similarity Coefficient (DSC) and median Hausdorff Distance at 95th percentile (HD95). For the PFS prediction task, challengers could use the tumor contours provided by experts (Task 3) or rely on their own (Task 2). The ranking was obtained according to the Concordance index (C-index) calculated on the predicted risk scores. A total of 103 teams registered for the challenge, for a total of 448 submissions and 29 papers. The best method in the segmentation task obtained an average DSC of 0.759, and the best predictions of PFS obtained a C-index of 0.717 (without relying on the provided contours) and 0.698 (using the expert contours). An interesting finding was that best PFS predictions were reached by relying on DL approaches (with or without explicit tumor segmentation, 4 out of the 5 best ranked) compared to standard radiomics methods using handcrafted features extracted from delineated tumors, and by exploiting alternative tumor contours (automated and/or larger volumes encompassing surrounding tissues) rather than relying on the expert contours. This second edition of the challenge confirmed the promising performance of fully automated primary tumor delineation in PET/CT images of HNC patients, although there is still a margin for improvement in some difficult cases. For the first time, the prediction of outcome was also addressed and the best methods reached relatively good performance (C-index above 0.7). Both results constitute another step forward toward large-scale outcome prediction studies in HNC

    68Ga-NODAGA-RGDyK PET/CT Imaging in Esophageal Cancer: First-in-Human Imaging.

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    Ga-NODAGA-RGDyK(cyclic) and FDG PET/CT were performed in a 39-year-old man for the work-up of a moderately differentiated carcinoma of the gastro-esophageal junction within a clinical study protocol. Although FDG PET images showed intense, diffuse hypermetabolic lesion activity, NODAGA-RGDyK illustrated the neo-angiogenesis process with tracer uptake clearly localized in non-FDG-avid perilesional structures. Neo-angiogenesis is characterized by ανβ3 integrin expression at the lesion surface of newly formed vessels. This case supports evidence that angiogenesis imaging might therefore be a crucial step in early disease identification and localization, metastatization potential, and in monitoring the efficacy of antiangiogenic therapies

    Diagnostic Performance of PET or PET/CT Using <sup>18</sup>F-FDG Labeled White Blood Cells in Infectious Diseases: A Systematic Review and a Bivariate Meta-Analysis.

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    Diagnostic performance of positron emission tomography using white blood cells labeled with fluorine-18-fluorodeoxyglucose ( &lt;sup&gt;18&lt;/sup&gt; F-FDG-WBC PET or PET/CT) in patients with suspicious infectious diseases has been evaluated in several studies; however, there is no consensus about the diagnostic accuracy of this method. Therefore, a systematic review and meta-analysis was carried out on this topic. A comprehensive computer literature search screening PubMed/MEDLINE, Embase and Cochrane library databases through March 2019 was performed. Pooled sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-), and diagnostic odds ratio (DOR) of &lt;sup&gt;18&lt;/sup&gt; F-FDG-WBC PET or PET/CT in patients with infectious diseases were calculated. Eight studies on the use of &lt;sup&gt;18&lt;/sup&gt; F-FDG-WBC PET or PET/CT in suspicious infectious diseases were discussed in the systematic review. The meta-analysis of seven studies (236 patients) provided these pooled results on a per patient-based analysis: sensitivity was 86.3% [95% confidence interval (95%CI) 75-92.9%], specificity 92% (95%CI 79.8-97.1%), LR+ 6.6 (95%CI: 3.1-14.1), LR- 0.2 (95%CI: 0.12-0.33), DOR 43.5 (95%CI: 12.2-155). A statistically significant heterogeneity was not detected. Despite limited literature data, &lt;sup&gt;18&lt;/sup&gt; F-FDG-WBC PET or PET/CT demonstrated a good diagnostic accuracy for the diagnosis of infectious diseases; nevertheless, larger studies are needed

    17 ways to say yes:Toward nuanced tone of voice in AAC and speech technology

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    People with complex communication needs who use speech-generating devices have very little expressive control over their tone of voice. Despite its importance in human interaction, the issue of tone of voice remains all but absent from AAC research and development however. In this paper, we describe three interdisciplinary projects, past, present and future: The critical design collection Six Speaking Chairs has provoked deeper discussion and inspired a social model of tone of voice; the speculative concept Speech Hedge illustrates challenges and opportunities in designing more expressive user interfaces; the pilot project Tonetable could enable participatory research and seed a research network around tone of voice. We speculate that more radical interactions might expand frontiers of AAC and disrupt speech technology as a whole

    The Term Structure of Interest Rates and its Impact on the Liability Adequacy Test for Insurance Companies in Brazil

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    The Brazilian regulation for applying the Liability Adequacy Test (LAT) to technical provisions in insurance companies requires that the current estimate is discounted by a term structure of interest rates (hereafter TSIR). This article aims to analyze the LAT results, derived from the use of various models to build the TSIR: the cubic spline interpolation technique, Svensson's model (adopted by the regulator) and Vasicek's model. In order to achieve the objective proposed, the exchange rates of BM&FBOVESPA trading days were used to model the ETTJ and, consequently, to discount the cash flow of the insurance company. The results indicate that: (i) LAT is sensitive to the choice of the model used to build the TSIR; (ii) this sensitivity increases with cash flow longevity; (iii) the adoption of an ultimate forward rate (UFR) for the Brazilian insurance market should be evaluated by the regulator, in order to stabilize the trajectory of the yield curve at longer maturities. The technical provision is among the main solvency items of insurance companies and the LAT result is a significant indicator of the quality of this provision, as this evaluates its sufficiency or insufficiency. Thus, this article bridges a gap in the Brazilian actuarial literature, introducing the main methodologies available for modeling the yield curve and a practical application to analyze the impact of its choice on LAT.</p

    Social disclosure and cost of equity in public companies in Brazil

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    Esta pesquisa tem por objetivo analisar a relação entre o nível de social disclosure e o custo de capital próprio em companhias abertas no Brasil. Assume-se a hipótese de que os programas sociais externos promovidos ou apoiados pelas empresas contribuem para a construção da imagem reputacional das organizações, compensando as externalidades, trazendo benefícios sob o ponto de vista econômico, pela relação negativa com o custo do capital. Para testar essa hipótese, foram coletados e analisados os relatórios de responsabilidade social de 83 empresas listadas na Bolsa de Valores, Mercadorias e Futuros de São Paulo (BM&FBovespa), no período de 2005 a 2009. Para avaliação do nível de social disclosure das empresas analisadas, foi utilizado um índice composto de 13 indicadores. O custo de capital próprio foi ajustado ao risco mediante o Capital Asset Pricing Model (CAPM) e testado por meio de regressão com dados em painel com efeitos fixos seccionais. Os resultados evidenciam que há relação negativa entre custo de capital próprio e nível de social disclosure, indicando, para o mercado acionário brasileiro, uma forma semiforte de eficiência de mercado. _________________________________________________________________________________ ABSTRACTThis study aims to analyze the relationship between the level of social disclosure and the cost of equity in public companies in Brazil. The hypothesis is that external social programs promoted or supported by a company increase the organization's reputation, compensate for externalities and bring economic benefits through the negative relationship with the cost of equity. To test this hypothesis, social responsibility reports of 83 companies listed on the São Paulo Stock, Mercantile and Futures Exchanges (Bolsa de Valores, Mercadorias e Futuros de São Paulo - BM&FBovespa) from the period 2005-2009 were collected and analyzed. A composite index of 13 indicators was used to evaluate the social disclosure level of the companies analyzed. The cost of equity was risk-adjusted using the capital asset-pricing model (CAPM) and regression tested using panel data with cross-sectional fixed effects. The results show a negative relationship between the cost of equity and level of social disclosure, indicating that the Brazilian stock market has a semi-strong form of market efficiency
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