Cost evaluation and comparison of three decision strategies for cardiac revascularization : results of the suspected CAD protocol of the European CMR registry

Background: The public health burden of coronary artery disease (CAD) is important. Perfusion cardiac magnetic resonance (CMR) is generally accepted to detect and monitor CAD. Few studies have so far addressed its costs and costeffectiveness. Objectives: To compare in a large CMR registry the costs of a CMR-guided strategy vs two hypothetical invasive strategies for the diagnosis and the treatment of patients with suspected CAD. Methods: In 3'647 patients with suspected CAD included prospectively in the EuroCMR Registry (59 centers; 18 countries) costs were calculated for diagnostic examinations, revascularizations as well as for complication management over a 1-year follow-up. Patients with ischemia-positive CMR underwent an invasive X-ray coronary angiography (CXA) and revascularization at the discretion of the treating physician (=CMR+CXA strategy). Ischemia was found in 20.9% of patients and 17.4% of them were revascularized. In ischemia-negative patients by CMR, cardiac death and non-fatal myocardial infarctions occurred in 0.38%/y. In a hypothetical invasive arm the costs were calculated for an initial CXA followed by FFR testing in vessels with ≥50% diameter stenoses (=CXA+FFR strategy). To model this hypothetical arm, the same proportion of ischemic patients and outcome was assumed as for the CMR+CXA strategy. The coronary stenosis - FFR relationship reported in the literature was used to derive the proportion of patients with ≥50% diameter stenoses (Psten) in the study cohort. The costs of a CXA-only strategy were also calculated. Calculations were performed from a third payer perspective for the German, UK, Swiss, and US healthcare systems.

Cost-minimization analysis of three decision strategies for cardiac revascularization : results of the "suspected CAD"cohort of the european cardiovascular magnetic resonance registry.

BACKGROUND: Coronary artery disease (CAD) continues to be one of the top public health burden. Perfusion cardiovascular magnetic resonance (CMR) is generally accepted to detect CAD, while data on its cost effectiveness are scarce. Therefore, the goal of the study was to compare the costs of a CMR-guided strategy vs two invasive strategies in a large CMR registry. METHODS: In 3'647 patients with suspected CAD of the EuroCMR-registry (59 centers/18 countries) costs were calculated for diagnostic examinations (CMR, X-ray coronary angiography (CXA) with/without FFR), revascularizations, and complications during a 1-year follow-up. Patients with ischemia-positive CMR underwent an invasive CXA and revascularization at the discretion of the treating physician (=CMR + CXA-strategy). In the hypothetical invasive arm, costs were calculated for an initial CXA and a FFR in vessels with ≥50 % stenoses (=CXA + FFR-strategy) and the same proportion of revascularizations and complications were applied as in the CMR + CXA-strategy. In the CXA-only strategy, costs included those for CXA and for revascularizations of all ≥50 % stenoses. To calculate the proportion of patients with ≥50 % stenoses, the stenosis-FFR relationship from the literature was used. Costs of the three strategies were determined based on a third payer perspective in 4 healthcare systems. RESULTS: Revascularizations were performed in 6.2 %, 4.5 %, and 12.9 % of all patients, patients with atypical chest pain (n = 1'786), and typical angina (n = 582), respectively; whereas complications (=all-cause death and non-fatal infarction) occurred in 1.3 %, 1.1 %, and 1.5 %, respectively. The CMR + CXA-strategy reduced costs by 14 %, 34 %, 27 %, and 24 % in the German, UK, Swiss, and US context, respectively, when compared to the CXA + FFR-strategy; and by 59 %, 52 %, 61 % and 71 %, respectively, versus the CXA-only strategy. In patients with typical angina, cost savings by CMR + CXA vs CXA + FFR were minimal in the German (2.3 %), intermediate in the US and Swiss (11.6 % and 12.8 %, respectively), and remained substantial in the UK (18.9 %) systems. Sensitivity analyses proved the robustness of results. CONCLUSIONS: A CMR + CXA-strategy for patients with suspected CAD provides substantial cost reduction compared to a hypothetical CXA + FFR-strategy in patients with low to intermediate disease prevalence. However, in the subgroup of patients with typical angina, cost savings were only minimal to moderate.

CAD e mamografia: por que usar esta ferramenta?

A mamografia representa o melhor método de detecção precoce do câncer de mama, porém cerca de 10% a 30% das lesões mamárias são perdidas no rastreamento, devido a limitações próprias dos observadores humanos. A detecção auxiliada por computador (computer-aided detection - CAD) é uma tecnologia relativamente nova que tem sido implementada em alguns serviços de mamografia, com o intuito de prover uma dupla leitura. Estudos clínicos têm demonstrado que o CAD aumenta a sensibilidade de detecção do câncer da mama, por radiologistas, em até 21%. Um sistema CAD é útil em situações em que exista alta variabilidade interobservador, falta de observadores treinados, ou na impossibilidade de se realizar a dupla leitura com dois ou mais radiologistas. O objetivo desta revisão está baseado na necessidade de atualizar a comunidade médica acerca desta ferramenta, como um método auxiliar, quantitativo, não operador-dependente, e que visa a melhorar a qualidade do diagnóstico do câncer de mama.

Més de tres segles d"història: les exploracions florístiques al Cadí-Moixeró i muntanyes veïnes.

El 2003 es va publicar el catàleg de plantes vasculars del Parc del Cadí-Moixeró i les serres veïnes; poc després un de nosaltres en va presentar una síntesi en el número 3 d"aquesta revista. Al·ludíem aleshores a l"important bagatge tant d"exploracions científiques com de dades sobre la flora del territori existents en el moment de redactar el catàleg; de fet, gairebé tots els botànics catalans, i molts de francesos i d"espanyols, hi han passat en algun moment i han contribuït al coneixement de la seva flora.

La Formación de Bellmunt (Unidad del Cadí, Pirineo Oriental): aportaciones bioestratigráficas de los sistemas lacustres y palustres asociados

La Formación de Bellmunt es una unidad aluvial de carácter sinorogénico relacionada con el emplaiamiento de 1os mantos pirenaicos.En suzonainferior-media intercala numerosos tramos lacustres y palustres que contienen una abundante fauna y flora fósil. Estos restos fósiles han permitido realizar la reconstrucción paleoambiental y paleoclimática de la zona, asi como precisar la cronoestratigrafia de la unidad, que corresponde a Bartoniense inferior-rnedio en base a las carófitas y a 1os restos de mamíferos.

Estudo comparativo sobre filtragem de sinais instrumentais usando transformadas de Fourier e Wavelet

A comparative study of the Fourier (FT) and the wavelet transforms (WT) for instrumental signal denoising is presented. The basic principles of wavelet theory are described in a succinct and simplified manner. For illustration, FT and WT are used to filter UV-VIS and plasma emission spectra using MATLAB software for computation. Results show that FT and WT filters are comparable when the signal does not display sharp peaks (UV-VIS spectra), but the WT yields a better filtering when the filling factor of the signal is small (plasma spectra), since it causes low peak distortion.

Combined application of continuous wavelet transform-zero crossing technique in the simultaneous spectrophotometric determination of perindopril and indapamid in tablets

Signal processing methods based on the combined use of the continuous wavelet transform (CWT) and zero-crossing technique were applied to the simultaneous spectrophotometric determination of perindopril (PER) and indapamide (IND) in tablets. These signal processing methods do not require any priory separation step. Initially, various wavelet families were tested to identify the optimum signal processing giving the best recovery results. From this procedure, the Haar and Biorthogonal1.5 continuous wavelet transform (HAAR-CWT and BIOR1.5-CWT, respectively) were found suitable for the analysis of the related compounds. After transformation of the absorbance vectors by using HAAR-CWT and BIOR1.5-CWT, the CWT-coefficients were drawn as a graph versus wavelength and then the HAAR-CWT and BIOR1.5-CWT spectra were obtained. Calibration graphs for PER and IND were obtained by measuring the CWT amplitudes at 231.1 and 291.0 nm in the HAAR-CWT spectra and at 228.5 and 246.8 nm in BIOR1.5-CWT spectra, respectively. In order to compare the performance of HAAR-CWT and BIOR1.5-CWT approaches, derivative spectrophotometric (DS) method and HPLC as comparison methods, were applied to the PER-IND samples. In this DS method, first derivative absorbance values at 221.6 for PER and 282.7 nm for IND were used to obtain the calibration graphs. The validation of the CWT and DS signal processing methods was carried out by using the recovery study and standard addition technique. In the following step, these methods were successfully applied to the commercial tablets containing PER and IND compounds and good accuracy and precision were reported for the experimental results obtained by all proposed signal processing methods.

CAD-CAM –tekniikalla valmistetut kokokeraamiset kruunut hammasimplanttihoidossa

Tämän kirjallisuuskatsauksen aiheena on CAD-CAM –tekniikalla valmistetut kokokeraamiset kruunut hammasimplanttihoidossa. Tarkoituksena on perehtyä implanttihoidossa käytettyjen kokokeraamisten kruunumateriaalien mekaanisiin ominaisuuksiin implanttien päällä, tarkastella niiden soveltuvuutta suun olosuhteisiin sekä kiinnittää huomiota myös ulkonäöllisiin seikkoihin. Toinen kirjallisuuskatsauksen tarkoitus on vertailla kokokeraamisia rakenteita aiemmin ja yhä yleisesti käytössä oleviin metallokeraamisiin kruunuihin. Kokokeraamiset kiinnikejatkeet sekä niiden päälle rakennetut kruunut ovat yleisesti kliinisessä käytössä, vaikka niiden käytöstä on pitkältä ajalta vain vähän tutkittua tietoa. Kirjallisuuskatsaukseen valitut tutkimukset käsittelevät kliinisesti yleisimmin käytettyjä materiaaleja. Kirjallisuuden lähteinä on käytetty Pubmed-tietokantaa. Tarkastelun kohteina ovat kokokeraamiset materiaalit: zirkonia, alumiinioksidi sekä vahvistetut lasikeraamiset materiaalit. Vertailu-materiaaleina ovat siltojen ja kruunujen runkorakenteena usein käytetyt metallit, kuten kromi-koboltti-, titaani- ja kultaseokset, ja tarkasteltavana on etenkin runkomateriaalin vaikutus kruunu-rakenteiden kestävyyksiin. Kirjallisuuskatsauksessa lähteinä käytetyissä tutkimuksissa on tarkasteltu materiaalien murtumislujuusarvoja, analysoitu murtumisten luonnetta sekä mitattu proteettisten rakenteiden istuvuuksia implanttien päällä. Kokokeraamiset kiinnikejatkeet eli ns. abutmentit ovat ulkonäöllisesti luonnollisen näköinen ratkaisu etualueilla. Zirkonian mekaaniset ominaisuudet ovat riittävät suurienkin purentavoimien alueilla, kuten molaarialueille asennettujen implanttien päällä. Zirkonian huokoisuus on alhainen ja sen bioyhteensopivuus erinomainen. Litiumdisilikaattilla vahvistettujen lasikeraamisten kruunujen murtumislujuusarvot ovat merkittävästi suuremmat titaanisten kiinnikejatkeiden päällä kuin zirkonia-kiinnikejatkeiden päällä, mutta materiaalin läpikuultavuus voi olla esteenä sen käytölle metallirakenteiden kanssa. Metallokeraamisten kruunujen ja siltojen murtumislujuusarvot implanttien päällä ovat suuremmat kuin kokokeraamisten rakenteiden. Kokokeraamisten kruunujen istuvuudet vaihtelivat tutkimuksesta ja mittaustavasta riippuen, mutta usein arvot vastasivat valumenetelmällä tehtyjen metallokeraamisten rakenteiden arvoja, ja olivat kliinisesti hyväksyttäviä.

Detection of patients with functional dyspepsia using wavelet transform applied to their electrogastrogram

The aim of the present study was to develop a classifier able to discriminate between healthy controls and dyspeptic patients by analysis of their electrogastrograms. Fifty-six electrogastrograms were analyzed, corresponding to 42 dyspeptic patients and 14 healthy controls. The original signals were subsampled, filtered and divided into the pre-, post-, and prandial stages. A time-frequency transformation based on wavelets was used to extract the signal characteristics, and a special selection procedure based on correlation was used to reduce their number. The analysis was carried out by evaluating different neural network structures to classify the wavelet coefficients into two groups (healthy subjects and dyspeptic patients). The optimization process of the classifier led to a linear model. A dimension reduction that resulted in only 25% of uncorrelated electrogastrogram characteristics gave 24 inputs for the classifier. The prandial stage gave the most significant results. Under these conditions, the classifier achieved 78.6% sensitivity, 92.9% specificity, and an error of 17.9 ± 6% (with a 95% confidence level). These data show that it is possible to establish significant differences between patients and normal controls when time-frequency characteristics are extracted from an electrogastrogram, with an adequate component reduction, outperforming the results obtained with classical Fourier analysis. These findings can contribute to increasing our understanding of the pathophysiological mechanisms involved in functional dyspepsia and perhaps to improving the pharmacological treatment of functional dyspeptic patients.

3D Mesh Simplification. A survey of algorithms and CAD model simplification tests

Simplification of highly detailed CAD models is an important step when CAD models are visualized or by other means utilized in augmented reality applications. Without simplification, CAD models may cause severe processing and storage is- sues especially in mobile devices. In addition, simplified models may have other advantages like better visual clarity or improved reliability when used for visual pose tracking. The geometry of CAD models is invariably presented in form of a 3D mesh. In this paper, we survey mesh simplification algorithms in general and focus especially to algorithms that can be used to simplify CAD models. We test some commonly known algorithms with real world CAD data and characterize some new CAD related simplification algorithms that have not been surveyed in previous mesh simplification reviews.

Diseño de una función wavelet madre para distinguir eventos transitorios en sistemas eléctricos de potencia.

Tesis (Maestría en Ciencias de la Ingeniería Eléctrica con Orientación en Sistemas Eléctricos de Potencia) UANL, 2010.

Estudio comparativo in vitro sobre la adaptación marginal en coronas de disilicato de litio : prensadas vs CAD

Tesis (Maestría en Odontología Restauradora) UANL, 2012.

Detection of microcalcifications in mammograms using local maxima andadaptive wavelet transform analysis

A method for computer- aided diagnosis of micro calcification clusters in mammograms images presented . Micro calcification clus.eni which are an early sign of bread cancer appear as isolated bright spots in mammograms. Therefore they correspond to local maxima of the image. The local maxima of the image is lint detected and they are ranked according to it higher-order statistical test performed over the sub band domain data