An Enhanced Visualization of DBT Imaging Using Blind Deconvolution and Total Variation Minimization Regularization

Digital Breast Tomosynthesis (DBT) presents out-of-plane artifacts caused by features of high intensity. Given observed data and knowledge about the point spread function (PSF), deconvolution techniques recover data from a blurred version. However, a correct PSF is difficult to achieve and these methods amplify noise. When no information is available about the PSF, blind deconvolution can be used. Additionally, Total Variation (TV) minimization algorithms have achieved great success due to its virtue of preserving edges while reducing image noise. This work presents a novel approach in DBT through the study of out-of-plane artifacts using blind deconvolution and noise regularization based on TV minimization. Gradient information was also included. The methodology was tested using real phantom data and one clinical data set. The results were investigated using conventional 2D slice-by-slice visualization and 3D volume rendering. For the 2D analysis, the artifact spread function (ASF) and Full Width at Half Maximum (FWHMMASF) of the ASF were considered. The 3D quantitative analysis was based on the FWHM of disks profiles at 90°, noise and signal to noise ratio (SNR) at 0° and 90°. A marked visual decrease of the artifact with reductions of FWHMASF (2D) and FWHM90° (volume rendering) of 23.8% and 23.6%, respectively, was observed. Although there was an expected increase in noise level, SNR values were preserved after deconvolution. Regardless of the methodology and visualization approach, the objective of reducing the out-of-plane artifact was accomplished. Both for the phantom and clinical case, the artifact reduction in the z was markedly visible

Impact of total variation minimization in volume rendering visualization of breast tomosynthesis data

Background and objective: Total Variation (TV) minimization algorithms have achieved great attention due to the virtue of decreasing noise while preserving edges. The purpose of this work is to implement and evaluate two TV minimization methods in 3D. Their performance is analyzed through 3D visualization of digital breast tomosynthesis (DBT) data with volume rendering. Methods: Both filters were studied with real phantom and one clinical DBT data. One algorithm was applied sequentially to all slices and the other was applied to the entire volume at once. The suitable Lagrange multiplier used in each filter equation was studied to reach the minimum 3D TV and the maximum contrast-to-noise ratio (CNR). Imaging blur was measured at 0° and 90° using two disks with different diameters (0.5 mm and 5.0 mm) and equal thickness. The quality of unfiltered and filtered data was analyzed with volume rendering at 0° and 90°. Results: For phantom data, with the sequential filter, a decrease of 25% in 3D TV value and an increase of 19% and 30% in CNR at 0° and 90°, respectively, were observed. When the filter is applied directly in 3D, TV value was reduced by 35% and an increase of 36% was achieved both for CNR at 0° and 90°. For the smaller disk, variations of 0% in width at half maximum (FWHM) at 0° and a decrease of about 2.5% for FWHM at 90° were observed for both filters. For the larger disk, there was a 2.5% increase in FWHM at 0° for both filters and a decrease of 6.28% and 1.69% in FWHM at 90° with the sequential filter and the 3D filter, respectively. When applied to clinical data, the performance of each filter was consistent with that obtained with the phantom. Conclusions: Data analysis confirmed the relevance of these methods in improving quality of DBT images. Additionally, this type of 3D visualization showed that it may play an important complementary role in DBT imaging. It allows to visualize all DBT data at once and to analyze properly filters applied to all the three dimensions

Cortisol salivar? como, quando e porquê? – análise de 15 anos de doseamentos de cortisol

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The technical challenge of Functional 18F-FDG-PET Brain imaging in paediatric epilepsy

Epilepsy is a chronic brain disease, characterized by the appearance of crisis (whit or without convulsions), caused by abnormal electric activity on brain cells. Neuroimaging might be necessary in the work-up of epilepsy for localisation of the seizure focus for possible surgical cure. In our department, we started performing inter-ictal 18F-2-deoxyglucose (FDG)-PET/TC Brain imaging in 2009, in paediatric patients, following EANM procedure guidelines. Aim: the aim of the study was to retrospectively review all the performed inter-ictal 18F-FDG-PET/TC brain imaging, to assess the difficulties found during these procedures and the deviation according to guideline recommendations. We also intend to focus on the major importance of an optimal cooperation with other departments, such as anaesthesiology and neurophysiology. Material and Methods: between 2009 and 2012, eleven patients (pt) were referred for an 18F-FDG-PET-TC brain study, with ages between 10 months - 18 years old all with medically intractable epilepsy. The exams were performed with different conditions according to the needs of each patient, because we know that exceptional procedures call for special conditions. Results: All files were review for pt information pertinent to performance of the procedure, pt pre-arrival preparation, pt pre-injection preparation, pt monitoring for ictal crises before injection (EEG), pt sedation, variability of radiopharmaceutical administration and data acquisition parameters. 8 of the pt were performed with anaesthesia while 3 without since the pediatric patient were cooperative. All of the pt were monitored under parental surveillance, one with additional movie recording and other with EEG. Conclusion: We found that this process of retrospective review of this pool of paediatric patients with epilepsy enhanced the learning curve in this very specific procedure. We also found it critical to request the collaboration of the departments of anaesthesiology and neurophysiology

OFF-LABEL USE OF ANTIBACTERIALS IN A CONTEXT OF ANTIMICROBIAL RESISTANCE THREAT

Objective: The objective of the study was to describe the off-label use of antibacterial in prescriptions for hospitalized adult patients as per the Brazilian drug regulatory agency, namely, the National Health Surveillance Agency (ANVISA). Methods: This is a cross-sectional study with prescriptions for inpatients in a teaching hospital. Data collection and analysis were based on the checklist of the Medicine Prescription, Use and Administration Protocol of the Ministry of Health, where the off-label use is classified as per information of ANVISA’s Electronic Bulletin. Descriptive analyses were performed, and the method of logistic regression was used to evaluate the association between the off-label use of antibacterial and the explanatory variables age, gender, hospitalization clinic, and medical specialty. Results: About one-third of the antibacterial was prescribed for off-label use, and the frequency of administration was the primary use outside standards established in the products’ licenses (87.3%), and dose (7.4%) and the administration route was next. The third-generation cephalosporin was the most consumed class in this regimen (69.5%). In some cases, the off-label use was not supported by scientific evidence. The off-label use was positively associated with the variables gender (odds ratio [OR] = 2.48; confidence interval [CI] = 1.23–4.92) and the prescribing clinic (OR = 4.94; CI = 2.61–8.96). Conclusion: Off-label use is a frequent practice in the studied environment, and in the face of a dramatic scenario of increased antibacterial resistance, it is imperative to adopt measures for the standardization of records and the rational use of this class of drugs

Micro-costing analysis of guideline-based treatment by direct-acting agents: the real-life case of hepatitis C management in Brazil

Background Eradication of hepatitis C virus (HCV) using direct-acting agents (DAA) has been associated with a financial burden to health authorities worldwide. We aimed to evaluate the guideline-based treatment costs by DAAs from the perspective of the Brazilian Ministry of Health (BMoH). Methods The activity based costing method was used to estimate the cost for monitoring/treatment of genotype-1 (GT1) HCV patients by the following strategies: peg-interferon (PEG-IFN)/ribavirin (RBV) for 48 weeks, PEG-IFN/RBV plus boceprevir (BOC) or telaprevir (TEL) for 48 weeks, and sofosbuvir (SOF) plus daclastavir (DCV) or simeprevir (SIM) for 12 weeks. Costs were reported in United States Dollars without (US$) and with adjustment for purchasing power parity (PPP$). Drug costs were collected at the National Database of Health Prices and an overview of the literature was performed to assess effectiveness of SOF/DCV and SOF/SIM regimens in real-world cohorts. Results Treatment costs of GT1-HCV patients were PPP$43,176.28 (US$ 24,020.16) for PEG-IFN/RBV, PPP$71,196.03 (US$ 39,578.23) for PEG-IFN/RBV/BOC and PPP$86,250.33 (US$ 47,946.92) for PEG-IFN/RBV/TEL. Treatment by all-oral interferon-free regimens were the less expensive approach: PPP$19,761.72 (US$ 10,985.90) for SOF/DCV and PPP$21,590.91 (US$ 12,002.75) for SOF/SIM. The overview reported HCV eradication in up to 98% for SOF/DCV and 96% for SOF/SIM. Conclusion Strategies with all oral interferon-free might lead to lower costs for management of GT1-HCV patients compared to IFN-based regimens in Brazil. This occurred mainly because of high discounts over international DAA prices due to negotiation between BMoH and pharmaceutical industries

Changes of Soluble CD40 Ligand in the Progression of Acute Myocardial Infarction Associate to Endothelial Nitric Oxide Synthase Polymorphisms and Vascular Endothelial Growth Factor But Not to Platelet CD62P Expression

Reported in vitro data implicated soluble CD40 ligand (sCD40L) in endothelial dysfunction and angiogenesis. However, whether sCD40L could exert that influence in endothelial dysfunction and angiogenesis after injury in acute myocardial infarction (AMI) patients remains unclear. In the present study, we evaluated the association of sCD40L with markers of platelet activation, endothelial, and vascular function during a recovery period early after AMI. To achieve this goal, the time changes of soluble, platelet-bound, and microparticle-bound CD40L levels over 1 month were assessed in AMI patients and correlated with endothelial nitric oxide synthase (eNOS) polymorphisms, vascular endothelial growth factor (VEGF) concentrations, and platelet expression of P-selectin (CD62P). The association of soluble form, platelet-bound, and microparticle-bound CD40L with CD62P expression on platelets, a marker of platelet activation, was also assessed to evaluate the role of CD40L in the thrombosis, whereas the association with eNOS and VEGF was to evaluate the role of CD40L in vascular dysfunction. This work shows for the first time that time changes of sCD40L over 1 month after myocardial infarct onset were associated with G894T eNOS polymorphism and with the VEGF concentrations, but not to the platelet CD62P expression. These results indicate that, in terms of AMI pathophysiology, the sCD40L cannot be consider just as being involved in thrombosis and inflammation but also as having a relevant role in vascular and endothelial dysfunction

Stratification of ST-Elevation Myocardial Infarction Patients Based on Soluble CD40L Longitudinal Changes

Involvement of soluble CD40 ligand (sCD40L) in thrombosis and inflammation on the context of coronary artery disease is currently being revised. In that perspective, we had studied the association of sCD40L with markers of platelet activation and markers of endothelial and vascular function. On that cohort, a stratification of patients with acute myocardial infarction (AMI) 1 month after percutaneous coronary intervention (PCI) was observed based on concentrations of sCD40L. The study intended to identify the groups of AMI patients with different profiles of sCD40L concentrations and verify how medication, clinical evolution, biochemical data, and markers of regulation of endothelial function at genetic (endothelial nitric oxide synthase polymorphisms) and post-transcriptional levels (circulating microRNAs) affect sCD40L serum levels. Lower quartiles of sCD40L (<2.3 ng/mL) were associated with higher concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP), high frequency of G894T polymorphism, and altered expression of a set of microRNAs assumed to be involved in the regulation of endothelial and cardiac function and myocardium hypertrophy, relative to patients in sCD40L upper quartiles. A characteristic sCD40L variation pattern in STEMI patients was identified. Low levels of sCD40L 1 month after PCI distinguish STEMI patients with worse prognosis, a compromised cardiac healing, and a persistent endothelial dysfunction, as given by the association between sCD40L, NT-proBNP, G894T polymorphism, and specific profile of miRNA expression. These results suggest sCD40L could have a prognostic value in STEMI patients.info:eu-repo/semantics/publishedVersio

An Evaluation of Prediction Equations for the 6 Minute Walk Test in Healthy European Adults Aged 50-85 Years

This study compared actual 6 minute walk test (6MWT) performance with predicted 6MWT using previously validated equations and then determined whether allometric modelling offers a sounder alternative to estimating 6MWT in adults aged 50-80 years.We compared actual 6MWT performance against predicted 6MWT in 125 adults aged 50-85 years (62 male, 63 female). In a second sample of 246 adults aged 50-85 years (74 male, 172 female), a new prediction equation for 6MWT performance was developed using allometric modelling. This equation was then cross validated using the same sample that the other prediction equations were compared with.Significant relationships were evident between 6MWT actual and 6MWT predicted using all of the commonly available prediction equations (all P<0.05 or better) with the exception of the Alameri et al prediction equation (P>0.05). A series of paired t-tests indicated significant differences between 6MWT actual and 6MWT predicted for all available prediction equations (all P<0.05 or better) with the exception of the Iwama et al equation (P = .540). The Iwama et al equation also had similar bias (79.8m) and a coefficient of variation of over 15%. Using sample 2, a log-linear model significantly predicted 6MWT from the log of body mass and height and age (P = 0.001, adjusted R2 = .526), predicting 52.6% of the variance in actual 6MWT. When this allometric equation was applied to the original sample, the relationship between 6MWT actual and 6MWT predicted was in excess of values reported for the other previously validated prediction equations (r = .706, P = 0.001). There was a significant difference between actual 6MWT and 6MWT predicted using this new equation (P = 0.001) but the bias, standard deviation of differences and coefficient of variation were all less than for the other equations.Where actual assessment of the 6MWT is not possible, the allometrically derived equation presented in the current study, offers a viable alternative which has been cross validated and has the least SD of differences and smallest coefficient of variation compared to any of the previously validated equations for the 6MWT