In Vitro Analysis of the Fracture Resistance of CAD/CAM Denture Base Resins

PubMed Central

Stöckl, Wolfgang; Dumfahrt, Herbert; Grunert, Ingrid

2018-01-01

Computer-aided design and computer-aided manufacturing (CAD/CAM) denture base manufacturers claim to produce their resin pucks under high heat and pressure. Therefore, CAD/CAM dentures are assumed to have enhanced mechanical properties and, as a result, are often produced with lower denture base thicknesses than conventional, manually fabricated dentures. The aim of this study was to investigate if commercially available CAD/CAM denture base resins have more favourable mechanical properties than conventionally processed denture base resins. For this purpose, a series of three-point bending tests conforming to ISO specifications were performed on a total of 80 standardised, rectangular CAD/CAM denture base resin specimens from five different manufacturers (AvaDent, Baltic Denture System, Vita VIONIC, Whole You Nexteeth, and Wieland Digital Dentures). A heat-polymerising resin and an autopolymerising resin served as the control groups. The breaking load, fracture toughness, and the elastic modulus were assessed. Additionally, the fracture surface roughness and texture were investigated. Only one CAD/CAM resin showed a significantly increased breaking load. Two CAD/CAM resins had a significantly higher fracture toughness than the control groups, and all CAD/CAM resins had higher elastic moduli than the controls. Our results indicate that CAD/CAM denture base resins do not generally have better mechanical properties than manually processed resins. Therefore, the lower minimum denture base thicknesses should be regarded with some caution. PMID:29518022

On the Use of Parmetric-CAD Systems and Cartesian Methods for Aerodynamic Design

NASA Technical Reports Server (NTRS)

Nemec, Marian; Aftosmis, Michael J.; Pulliam, Thomas H.

2004-01-01

Automated, high-fidelity tools for aerodynamic design face critical issues in attempting to optimize real-life geometry arid in permitting radical design changes. Success in these areas promises not only significantly shorter design- cycle times, but also superior and unconventional designs. To address these issues, we investigate the use of a parmetric-CAD system in conjunction with an embedded-boundary Cartesian method. Our goal is to combine the modeling capabilities of feature-based CAD with the robustness and flexibility of component-based Cartesian volume-mesh generation for complex geometry problems. We present the development of an automated optimization frame-work with a focus on the deployment of such a CAD-based design approach in a heterogeneous parallel computing environment.

Space crew radiation exposure analysis system based on a commercial stand-alone CAD system

NASA Technical Reports Server (NTRS)

Appleby, Matthew H.; Golightly, Michael J.; Hardy, Alva C.

1992-01-01

Major improvements have recently been completed in the approach to spacecraft shielding analysis. A Computer-Aided Design (CAD)-based system has been developed for determining the shielding provided to any point within or external to the spacecraft. Shielding analysis is performed using a commercially available stand-alone CAD system and a customized ray-tracing subroutine contained within a standard engineering modeling software package. This improved shielding analysis technique has been used in several vehicle design projects such as a Mars transfer habitat, pressurized lunar rover, and the redesigned Space Station. Results of these analyses are provided to demonstrate the applicability and versatility of the system.

CAD-RADS - a new clinical decision support tool for coronary computed tomography angiography.

PubMed

Foldyna, Borek; Szilveszter, Bálint; Scholtz, Jan-Erik; Banerji, Dahlia; Maurovich-Horvat, Pál; Hoffmann, Udo

2018-04-01

Coronary computed tomography angiography (CTA) has been established as an accurate method to non-invasively assess coronary artery disease (CAD). The proposed 'Coronary Artery Disease Reporting and Data System' (CAD-RADS) may enable standardised reporting of the broad spectrum of coronary CTA findings related to the presence, extent and composition of coronary atherosclerosis. The CAD-RADS classification is a comprehensive tool for summarising findings on a per-patient-basis dependent on the highest-grade coronary artery lesion, ranging from CAD-RADS 0 (absence of CAD) to CAD-RADS 5 (total occlusion of a coronary artery). In addition, it provides suggestions for clinical management for each classification, including further testing and therapeutic options. Despite some limitations, CAD-RADS may facilitate improved communication between imagers and patient caregivers. As such, CAD-RADS may enable a more efficient use of coronary CTA leading to more accurate utilisation of invasive coronary angiograms. Furthermore, widespread use of CAD-RADS may facilitate registry-based research of diagnostic and prognostic aspects of CTA. • CAD-RADS is a tool for standardising coronary CTA reports. • CAD-RADS includes clinical treatment recommendations based on CTA findings. • CAD-RADS has the potential to reduce variability of CTA reports.

A step-by-step introduction to rule-based design of synthetic genetic constructs using GenoCAD.

PubMed

Wilson, Mandy L; Hertzberg, Russell; Adam, Laura; Peccoud, Jean

2011-01-01

GenoCAD is an open source web-based system that provides a streamlined, rule-driven process for designing genetic sequences. GenoCAD provides a graphical interface that allows users to design sequences consistent with formalized design strategies specific to a domain, organization, or project. Design strategies include limited sets of user-defined parts and rules indicating how these parts are to be combined in genetic constructs. In addition to reducing design time to minutes, GenoCAD improves the quality and reliability of the finished sequence by ensuring that the designs follow established rules of sequence construction. GenoCAD.org is a publicly available instance of GenoCAD that can be found at www.genocad.org. The source code and latest build are available from SourceForge to allow advanced users to install and customize GenoCAD for their unique needs. This chapter focuses primarily on how the GenoCAD tools can be used to organize genetic parts into customized personal libraries, then how these libraries can be used to design sequences. In addition, GenoCAD's parts management system and search capabilities are described in detail. Instructions are provided for installing a local instance of GenoCAD on a server. Some of the future enhancements of this rapidly evolving suite of applications are briefly described. Copyright © 2011 Elsevier Inc. All rights reserved.

An online real-time DICOM web-based computer-aided diagnosis system for bone age assessment of children in a PACS environment

NASA Astrophysics Data System (ADS)

Ma, Kevin C.; Zhang, Aifeng; Moin, Paymann; Fleshman, Mariam; Vachon, Linda; Liu, Brent; Huang, H. K.

2009-02-01

Bone age assessment is a radiological procedure to evaluate a child's bone age based on his or her left-hand x-ray image. The current standard is to match patient's hand with Greulich & Pyle hand atlas, which is outdated by 50 years and only uses subjects from one region and one ethnicity. To improve bone age assessment accuracy for today's children, an automated race- and gender-specific bone age assessment (BAA) system has been developed in IPILab. 1390 normal left-hand x-ray images have been collected at Children's Hospital of Los Angeles (CHLA) to form the digital hand atlas (DHA). DHA includes both male and female children of ages one to eighteen and of four ethnic groups: African American, Asian American, Caucasian, and Hispanic. In order to apply DHA and BAA CAD into a clinical environment, a web-based BAA CAD system and graphical user interface (GUI) has been implemented in Women and Children's Hospital at Los Angeles County (WCH-LAC). A CAD server has been integrated in WCH's PACS environment, and a clinical validation workflow has been designed for radiologists, who compare CAD readings with G&P readings and determine which reading is more suited for a certain case. Readings are logged in database and analyzed to assess BAA CAD performance in a clinical setting. The result is a successful installation of web-based BAA CAD system in a clinical setting.

Computer-aided diagnosis of prostate cancer using multi-parametric MRI: comparison between PUN and Tofts models

NASA Astrophysics Data System (ADS)

Mazzetti, S.; Giannini, V.; Russo, F.; Regge, D.

2018-05-01

Computer-aided diagnosis (CAD) systems are increasingly being used in clinical settings to report multi-parametric magnetic resonance imaging (mp-MRI) of the prostate. Usually, CAD systems automatically highlight cancer-suspicious regions to the radiologist, reducing reader variability and interpretation errors. Nevertheless, implementing this software requires the selection of which mp-MRI parameters can best discriminate between malignant and non-malignant regions. To exploit functional information, some parameters are derived from dynamic contrast-enhanced (DCE) acquisitions. In particular, much CAD software employs pharmacokinetic features, such as K trans and k ep, derived from the Tofts model, to estimate a likelihood map of malignancy. However, non-pharmacokinetic models can be also used to describe DCE-MRI curves, without any requirement for prior knowledge or measurement of the arterial input function, which could potentially lead to large errors in parameter estimation. In this work, we implemented an empirical function derived from the phenomenological universalities (PUN) class to fit DCE-MRI. The parameters of the PUN model are used in combination with T2-weighted and diffusion-weighted acquisitions to feed a support vector machine classifier to produce a voxel-wise malignancy likelihood map of the prostate. The results were all compared to those for a CAD system based on Tofts pharmacokinetic features to describe DCE-MRI curves, using different quality aspects of image segmentation, while also evaluating the number and size of false positive (FP) candidate regions. This study included 61 patients with 70 biopsy-proven prostate cancers (PCa). The metrics used to evaluate segmentation quality between the two CAD systems were not statistically different, although the PUN-based CAD reported a lower number of FP, with reduced size compared to the Tofts-based CAD. In conclusion, the CAD software based on PUN parameters is a feasible means with which to detect PCa, without affecting segmentation quality, and hence it could be successfully applied in clinical settings, improving the automated diagnosis process and reducing computational complexity.

Development of Cad System for Diffuse Disease Based on Ultrasound Elasticity Images

NASA Astrophysics Data System (ADS)

Yamazaki, M.; Shiina, T.; Yamakawa, M.; Takizawa, H.; Tonomura, A.; Mitake, T.

It is well known that as hepatic cirrhosis progresses, hepatocyte fibrosis spreads and nodule increases. However, it is not easy to diagnosis its early stage by conventional B-mode image because we have to read subtle change of speckle pattern which is not sensitive to the stage of fibrosis. Ultrasonic tissue elasticity imaging can provide us novel diagnostic information based on tissue hardness. We recently developed commercial-based equipment for tissue elasticity imaging. In this work, we investigated to develop the CAD system based on elasticity image for diagnosing defused type diseases such as hepatic cirrhosis. The results of clinical data analysis indicate that the CAD system is promising as means for diagnosis of diffuse disease with simple criterion.

PACS-Based Computer-Aided Detection and Diagnosis

NASA Astrophysics Data System (ADS)

Huang, H. K. (Bernie); Liu, Brent J.; Le, Anh HongTu; Documet, Jorge

The ultimate goal of Picture Archiving and Communication System (PACS)-based Computer-Aided Detection and Diagnosis (CAD) is to integrate CAD results into daily clinical practice so that it becomes a second reader to aid the radiologist's diagnosis. Integration of CAD and Hospital Information System (HIS), Radiology Information System (RIS) or PACS requires certain basic ingredients from Health Level 7 (HL7) standard for textual data, Digital Imaging and Communications in Medicine (DICOM) standard for images, and Integrating the Healthcare Enterprise (IHE) workflow profiles in order to comply with the Health Insurance Portability and Accountability Act (HIPAA) requirements to be a healthcare information system. Among the DICOM standards and IHE workflow profiles, DICOM Structured Reporting (DICOM-SR); and IHE Key Image Note (KIN), Simple Image and Numeric Report (SINR) and Post-processing Work Flow (PWF) are utilized in CAD-HIS/RIS/PACS integration. These topics with examples are presented in this chapter.

Impact of IPAD on CAD/CAM database university research

NASA Technical Reports Server (NTRS)

Leach, L. M.; Wozny, M. J.

1984-01-01

IPAD program has provided direction, focus and software products which impacted on CAD/CAM data base research and follow-on research. The relationship of IPAD to the research projects which involve the storage of geometric data in common data ase facilities such as data base machines, the exchange of data between heterogeneous data bases, the development of IGES processors, the migration of lrge CAD/CAM data base management systems to noncompatible hosts, and the value of RIM as a research tool is described.

The design and integration of retinal CAD-SR to diabetes patient ePR system

NASA Astrophysics Data System (ADS)

Wu, Huiqun; Wei, Yufang; Liu, Brent J.; Shang, Yujuan; Shi, Lili; Jiang, Kui; Dong, Jiancheng

2017-03-01

Diabetic retinopathy (DR) is one of the serious complications of diabetes that could lead to blindness. Digital fundus camera is often used to detect retinal changes but the diagnosis relies too much on ophthalmologist's experience. Based on our previously developed algorithms for quantifying retinal vessels and lesions, we developed a computer aided detection-structured report (CAD-SR) template and implemented it into picture archiving and communication system (PACS). Furthermore, we mapped our CAD-SR into HL7 CDA to integrate CAD findings into diabetes patient electronic patient record (ePR) system. Such integration could provide more quantitative features from fundus image into ePR system, which is valuable for further data mining researches.

True Concurrent Thermal Engineering Integrating CAD Model Building with Finite Element and Finite Difference Methods

NASA Technical Reports Server (NTRS)

Panczak, Tim; Ring, Steve; Welch, Mark

1999-01-01

Thermal engineering has long been left out of the concurrent engineering environment dominated by CAD (computer aided design) and FEM (finite element method) software. Current tools attempt to force the thermal design process into an environment primarily created to support structural analysis, which results in inappropriate thermal models. As a result, many thermal engineers either build models "by hand" or use geometric user interfaces that are separate from and have little useful connection, if any, to CAD and FEM systems. This paper describes the development of a new thermal design environment called the Thermal Desktop. This system, while fully integrated into a neutral, low cost CAD system, and which utilizes both FEM and FD methods, does not compromise the needs of the thermal engineer. Rather, the features needed for concurrent thermal analysis are specifically addressed by combining traditional parametric surface based radiation and FD based conduction modeling with CAD and FEM methods. The use of flexible and familiar temperature solvers such as SINDA/FLUINT (Systems Improved Numerical Differencing Analyzer/Fluid Integrator) is retained.

Computer-aided diagnosis: A survey with bibliometric analysis.

PubMed

Takahashi, Ryohei; Kajikawa, Yuya

2017-05-01

Computer-aided diagnosis (CAD) has been a promising area of research over the last two decades. However, CAD is a very complicated subject because it involves a number of medicine and engineering-related fields. To develop a research overview of CAD, we conducted a literature survey with bibliometric analysis, which we report here. Our study determined that CAD research has been classified and categorized according to disease type and imaging modality. This classification began with the CAD of mammograms and eventually progressed to that of brain disease. Furthermore, based on our results, we discuss future directions and opportunities for CAD research. First, in contrast to the typical hypothetical approach, the data-driven approach has shown promise. Second, the normalization of the test datasets and an evaluation method is necessary when adopting an algorithm and a system. Third, we discuss opportunities for the co-evolution of CAD research and imaging instruments-for example, the CAD of bones and pancreatic cancer. Fourth, the potential of synergy with CAD and clinical decision support systems is also discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Computer-aided detection of breast lesions in DCE-MRI using region growing based on fuzzy C-means clustering and vesselness filter

NASA Astrophysics Data System (ADS)

B. Shokouhi, Shahriar; Fooladivanda, Aida; Ahmadinejad, Nasrin

2017-12-01

A computer-aided detection (CAD) system is introduced in this paper for detection of breast lesions in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The proposed CAD system firstly compensates motion artifacts and segments the breast region. Then, the potential lesion voxels are detected and used as the initial seed points for the seeded region-growing algorithm. A new and robust region-growing algorithm incorporating with Fuzzy C-means (FCM) clustering and vesselness filter is proposed to segment any potential lesion regions. Subsequently, the false positive detections are reduced by applying a discrimination step. This is based on 3D morphological characteristics of the potential lesion regions and kinetic features which are fed to the support vector machine (SVM) classifier. The performance of the proposed CAD system is evaluated using the free-response operating characteristic (FROC) curve. We introduce our collected dataset that includes 76 DCE-MRI studies, 63 malignant and 107 benign lesions. The prepared dataset has been used to verify the accuracy of the proposed CAD system. At 5.29 false positives per case, the CAD system accurately detects 94% of the breast lesions.

Evaluation of information-theoretic similarity measures for content-based retrieval and detection of masses in mammograms.

PubMed

Tourassi, Georgia D; Harrawood, Brian; Singh, Swatee; Lo, Joseph Y; Floyd, Carey E

2007-01-01

The purpose of this study was to evaluate image similarity measures employed in an information-theoretic computer-assisted detection (IT-CAD) scheme. The scheme was developed for content-based retrieval and detection of masses in screening mammograms. The study is aimed toward an interactive clinical paradigm where physicians query the proposed IT-CAD scheme on mammographic locations that are either visually suspicious or indicated as suspicious by other cuing CAD systems. The IT-CAD scheme provides an evidence-based, second opinion for query mammographic locations using a knowledge database of mass and normal cases. In this study, eight entropy-based similarity measures were compared with respect to retrieval precision and detection accuracy using a database of 1820 mammographic regions of interest. The IT-CAD scheme was then validated on a separate database for false positive reduction of progressively more challenging visual cues generated by an existing, in-house mass detection system. The study showed that the image similarity measures fall into one of two categories; one category is better suited to the retrieval of semantically similar cases while the second is more effective with knowledge-based decisions regarding the presence of a true mass in the query location. In addition, the IT-CAD scheme yielded a substantial reduction in false-positive detections while maintaining high detection rate for malignant masses.

Evaluation of information-theoretic similarity measures for content-based retrieval and detection of masses in mammograms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tourassi, Georgia D.; Harrawood, Brian; Singh, Swatee

The purpose of this study was to evaluate image similarity measures employed in an information-theoretic computer-assisted detection (IT-CAD) scheme. The scheme was developed for content-based retrieval and detection of masses in screening mammograms. The study is aimed toward an interactive clinical paradigm where physicians query the proposed IT-CAD scheme on mammographic locations that are either visually suspicious or indicated as suspicious by other cuing CAD systems. The IT-CAD scheme provides an evidence-based, second opinion for query mammographic locations using a knowledge database of mass and normal cases. In this study, eight entropy-based similarity measures were compared with respect to retrievalmore » precision and detection accuracy using a database of 1820 mammographic regions of interest. The IT-CAD scheme was then validated on a separate database for false positive reduction of progressively more challenging visual cues generated by an existing, in-house mass detection system. The study showed that the image similarity measures fall into one of two categories; one category is better suited to the retrieval of semantically similar cases while the second is more effective with knowledge-based decisions regarding the presence of a true mass in the query location. In addition, the IT-CAD scheme yielded a substantial reduction in false-positive detections while maintaining high detection rate for malignant masses.« less

Recommendations for research design and reporting in computer-assisted diagnosis to facilitate meta-analysis.

PubMed

Eadie, Leila H; Taylor, Paul; Gibson, Adam P

2012-04-01

Computer-assisted diagnosis (CAD) describes a diverse, heterogeneous range of applications rather than a single entity. The aims and functions of CAD systems vary considerably and comparing studies and systems is challenging due to methodological and design differences. In addition, poor study quality and reporting can reduce the value of some publications. Meta-analyses of CAD are therefore difficult and may not provide reliable conclusions. Aiming to determine the major sources of heterogeneity and thereby what CAD researchers could change to allow this sort of assessment, this study reviews a sample of 147 papers concerning CAD used with imaging for cancer diagnosis. It discusses sources of variability, including the goal of the CAD system, learning methodology, study population, design, outcome measures, inclusion of radiologists, and study quality. Based upon this evidence, recommendations are made to help researchers optimize the quality and comparability of their trial design and reporting. Copyright © 2011 Elsevier Inc. All rights reserved.

Mass detection in digital breast tomosynthesis: Deep convolutional neural network with transfer learning from mammography.

PubMed

Samala, Ravi K; Chan, Heang-Ping; Hadjiiski, Lubomir; Helvie, Mark A; Wei, Jun; Cha, Kenny

2016-12-01

Develop a computer-aided detection (CAD) system for masses in digital breast tomosynthesis (DBT) volume using a deep convolutional neural network (DCNN) with transfer learning from mammograms. A data set containing 2282 digitized film and digital mammograms and 324 DBT volumes were collected with IRB approval. The mass of interest on the images was marked by an experienced breast radiologist as reference standard. The data set was partitioned into a training set (2282 mammograms with 2461 masses and 230 DBT views with 228 masses) and an independent test set (94 DBT views with 89 masses). For DCNN training, the region of interest (ROI) containing the mass (true positive) was extracted from each image. False positive (FP) ROIs were identified at prescreening by their previously developed CAD systems. After data augmentation, a total of 45 072 mammographic ROIs and 37 450 DBT ROIs were obtained. Data normalization and reduction of non-uniformity in the ROIs across heterogeneous data was achieved using a background correction method applied to each ROI. A DCNN with four convolutional layers and three fully connected (FC) layers was first trained on the mammography data. Jittering and dropout techniques were used to reduce overfitting. After training with the mammographic ROIs, all weights in the first three convolutional layers were frozen, and only the last convolution layer and the FC layers were randomly initialized again and trained using the DBT training ROIs. The authors compared the performances of two CAD systems for mass detection in DBT: one used the DCNN-based approach and the other used their previously developed feature-based approach for FP reduction. The prescreening stage was identical in both systems, passing the same set of mass candidates to the FP reduction stage. For the feature-based CAD system, 3D clustering and active contour method was used for segmentation; morphological, gray level, and texture features were extracted and merged with a linear discriminant classifier to score the detected masses. For the DCNN-based CAD system, ROIs from five consecutive slices centered at each candidate were passed through the trained DCNN and a mass likelihood score was generated. The performances of the CAD systems were evaluated using free-response ROC curves and the performance difference was analyzed using a non-parametric method. Before transfer learning, the DCNN trained only on mammograms with an AUC of 0.99 classified DBT masses with an AUC of 0.81 in the DBT training set. After transfer learning with DBT, the AUC improved to 0.90. For breast-based CAD detection in the test set, the sensitivity for the feature-based and the DCNN-based CAD systems was 83% and 91%, respectively, at 1 FP/DBT volume. The difference between the performances for the two systems was statistically significant (p-value < 0.05). The image patterns learned from the mammograms were transferred to the mass detection on DBT slices through the DCNN. This study demonstrated that large data sets collected from mammography are useful for developing new CAD systems for DBT, alleviating the problem and effort of collecting entirely new large data sets for the new modality.

Prototypes for Content-Based Image Retrieval in Clinical Practice

PubMed Central

Depeursinge, Adrien; Fischer, Benedikt; Müller, Henning; Deserno, Thomas M

2011-01-01

Content-based image retrieval (CBIR) has been proposed as key technology for computer-aided diagnostics (CAD). This paper reviews the state of the art and future challenges in CBIR for CAD applied to clinical practice. We define applicability to clinical practice by having recently demonstrated the CBIR system on one of the CAD demonstration workshops held at international conferences, such as SPIE Medical Imaging, CARS, SIIM, RSNA, and IEEE ISBI. From 2009 to 2011, the programs of CADdemo@CARS and the CAD Demonstration Workshop at SPIE Medical Imaging were sought for the key word “retrieval” in the title. The systems identified were analyzed and compared according to the hierarchy of gaps for CBIR systems. In total, 70 software demonstrations were analyzed. 5 systems were identified meeting the criterions. The fields of application are (i) bone age assessment, (ii) bone fractures, (iii) interstitial lung diseases, and (iv) mammography. Bridging the particular gaps of semantics, feature extraction, feature structure, and evaluation have been addressed most frequently. In specific application domains, CBIR technology is available for clinical practice. While system development has mainly focused on bridging content and feature gaps, performance and usability have become increasingly important. The evaluation must be based on a larger set of reference data, and workflow integration must be achieved before CBIR-CAD is really established in clinical practice. PMID:21892374

Computer-aided diagnosis for classifying benign versus malignant thyroid nodules based on ultrasound images: A comparison with radiologist-based assessments.

PubMed

Chang, Yongjun; Paul, Anjan Kumar; Kim, Namkug; Baek, Jung Hwan; Choi, Young Jun; Ha, Eun Ju; Lee, Kang Dae; Lee, Hyoung Shin; Shin, DaeSeock; Kim, Nakyoung

2016-01-01

To develop a semiautomated computer-aided diagnosis (cad) system for thyroid cancer using two-dimensional ultrasound images that can be used to yield a second opinion in the clinic to differentiate malignant and benign lesions. A total of 118 ultrasound images that included axial and longitudinal images from patients with biopsy-confirmed malignant (n = 30) and benign (n = 29) nodules were collected. Thyroid cad software was developed to extract quantitative features from these images based on thyroid nodule segmentation in which adaptive diffusion flow for active contours was used. Various features, including histogram, intensity differences, elliptical fit, gray-level co-occurrence matrixes, and gray-level run-length matrixes, were evaluated for each region imaged. Based on these imaging features, a support vector machine (SVM) classifier was used to differentiate benign and malignant nodules. Leave-one-out cross-validation with sequential forward feature selection was performed to evaluate the overall accuracy of this method. Additionally, analyses with contingency tables and receiver operating characteristic (ROC) curves were performed to compare the performance of cad with visual inspection by expert radiologists based on established gold standards. Most univariate features for this proposed cad system attained accuracies that ranged from 78.0% to 83.1%. When optimal SVM parameters that were established using a grid search method with features that radiologists use for visual inspection were employed, the authors could attain rates of accuracy that ranged from 72.9% to 84.7%. Using leave-one-out cross-validation results in a multivariate analysis of various features, the highest accuracy achieved using the proposed cad system was 98.3%, whereas visual inspection by radiologists reached 94.9% accuracy. To obtain the highest accuracies, "axial ratio" and "max probability" in axial images were most frequently included in the optimal feature sets for the authors' proposed cad system, while "shape" and "calcification" in longitudinal images were most frequently included in the optimal feature sets for visual inspection by radiologists. The computed areas under curves in the ROC analysis were 0.986 and 0.979 for the proposed cad system and visual inspection by radiologists, respectively; no significant difference was detected between these groups. The use of thyroid cad to differentiate malignant from benign lesions shows accuracy similar to that obtained via visual inspection by radiologists. Thyroid cad might be considered a viable way to generate a second opinion for radiologists in clinical practice.

Computer-aided diagnosis for classifying benign versus malignant thyroid nodules based on ultrasound images: A comparison with radiologist-based assessments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Yongjun; Paul, Anjan Kumar; Kim, Namkug, E-mail: namkugkim@gmail.com

Purpose: To develop a semiautomated computer-aided diagnosis (CAD) system for thyroid cancer using two-dimensional ultrasound images that can be used to yield a second opinion in the clinic to differentiate malignant and benign lesions. Methods: A total of 118 ultrasound images that included axial and longitudinal images from patients with biopsy-confirmed malignant (n = 30) and benign (n = 29) nodules were collected. Thyroid CAD software was developed to extract quantitative features from these images based on thyroid nodule segmentation in which adaptive diffusion flow for active contours was used. Various features, including histogram, intensity differences, elliptical fit, gray-level co-occurrencemore » matrixes, and gray-level run-length matrixes, were evaluated for each region imaged. Based on these imaging features, a support vector machine (SVM) classifier was used to differentiate benign and malignant nodules. Leave-one-out cross-validation with sequential forward feature selection was performed to evaluate the overall accuracy of this method. Additionally, analyses with contingency tables and receiver operating characteristic (ROC) curves were performed to compare the performance of CAD with visual inspection by expert radiologists based on established gold standards. Results: Most univariate features for this proposed CAD system attained accuracies that ranged from 78.0% to 83.1%. When optimal SVM parameters that were established using a grid search method with features that radiologists use for visual inspection were employed, the authors could attain rates of accuracy that ranged from 72.9% to 84.7%. Using leave-one-out cross-validation results in a multivariate analysis of various features, the highest accuracy achieved using the proposed CAD system was 98.3%, whereas visual inspection by radiologists reached 94.9% accuracy. To obtain the highest accuracies, “axial ratio” and “max probability” in axial images were most frequently included in the optimal feature sets for the authors’ proposed CAD system, while “shape” and “calcification” in longitudinal images were most frequently included in the optimal feature sets for visual inspection by radiologists. The computed areas under curves in the ROC analysis were 0.986 and 0.979 for the proposed CAD system and visual inspection by radiologists, respectively; no significant difference was detected between these groups. Conclusions: The use of thyroid CAD to differentiate malignant from benign lesions shows accuracy similar to that obtained via visual inspection by radiologists. Thyroid CAD might be considered a viable way to generate a second opinion for radiologists in clinical practice.« less

Potential effect of CAD systems on the detection of actionable nodules in chest CT scans during routine reporting

NASA Astrophysics Data System (ADS)

Wormanns, Dag; Beyer, Florian; Butzbach, Arnauld; Zierott, Livia; Heindel, Walter

2006-03-01

The purpose of the presented study was to determine the impact of two different CAD systems used as concur-rent reader for detection of actionable nodules (>4 mm) on the interpretation of chest CT scans during routine reporting. Fifty consecutive MDCT scans (1 mm or 1.25 mm slice thickness, 0.8 mm reconstruction increment) were se-lected from clinical routine. All cases were read by a resident and a staff radiologist, and a written report was available in the radiology information system (RIS). The RIS report mentioned at least one actionable pulmonary nodule in 18 cases (50%) and did not report any pulmonary nodule in the remaining 32 cases. Two different recent CAD systems were independently applied to the 50 CT scans as concurrent reader with two radiologists: Siemens LungCare NEV and MEDIAN CAD-Lung. Two radiologists independently reviewed the CAD results and determined if a CAD result was a true positive or a false positive finding. Patients were classified into two groups: in group A if at least one actionable nodule was detected and in group B if no actionable nodules were found. The effect of CAD on routine reporting was simulated as set union of the findings of routine reporting and CAD thus applying CAD as concurrent reader. According to the RIS report group A (patients with at least one actionable nodule) contained 18 cases (36% of all 50 cases), and group B contained 32 cases. Application of a CAD system as concurrent reader resulted in detec-tion of additional CT scans with actionable nodules and reclassification into group A in 16 resp. 18 cases (radi-ologist 1 resp. radiologist 2) with Siemens NEV and in 19 resp. 18 cases with MEDIAN CAD-Lung. In seven cases MEDIAN CAD-Lung and in four cases Siemens NEV reclassified a case into group A while the other CAD system missed the relevant finding. Sensitivity on a nodule (>4 mm) base was .45 for Siemens NEV and .55 for MEDIAN CAD-Lung; the difference was not yet significant (p=.077). In our study use of CAD as second reader in routine reporting doubled the percentage of patients with actionable nodules larger than 4 mm.

An automated distinction of DICOM images for lung cancer CAD system

NASA Astrophysics Data System (ADS)

Suzuki, H.; Saita, S.; Kubo, M.; Kawata, Y.; Niki, N.; Nishitani, H.; Ohmatsu, H.; Eguchi, K.; Kaneko, M.; Moriyama, N.

2009-02-01

Automated distinction of medical images is an important preprocessing in Computer-Aided Diagnosis (CAD) systems. The CAD systems have been developed using medical image sets with specific scan conditions and body parts. However, varied examinations are performed in medical sites. The specification of the examination is contained into DICOM textual meta information. Most DICOM textual meta information can be considered reliable, however the body part information cannot always be considered reliable. In this paper, we describe an automated distinction of DICOM images as a preprocessing for lung cancer CAD system. Our approach uses DICOM textual meta information and low cost image processing. Firstly, the textual meta information such as scan conditions of DICOM image is distinguished. Secondly, the DICOM image is set to distinguish the body parts which are identified by image processing. The identification of body parts is based on anatomical structure which is represented by features of three regions, body tissue, bone, and air. The method is effective to the practical use of lung cancer CAD system in medical sites.

Development of a web-based DICOM-SR viewer for CAD data of multiple sclerosis lesions in an imaging informatics-based efolder

NASA Astrophysics Data System (ADS)

Ma, Kevin; Wong, Jonathan; Zhong, Mark; Zhang, Jeff; Liu, Brent

2014-03-01

In the past, we have presented an imaging-informatics based eFolder system for managing and analyzing imaging and lesion data of multiple sclerosis (MS) patients, which allows for data storage, data analysis, and data mining in clinical and research settings. The system integrates the patient's clinical data with imaging studies and a computer-aided detection (CAD) algorithm for quantifying MS lesion volume, lesion contour, locations, and sizes in brain MRI studies. For compliance with IHE integration protocols, long-term storage in PACS, and data query and display in a DICOM compliant clinical setting, CAD results need to be converted into DICOM-Structured Report (SR) format. Open-source dcmtk and customized XML templates are used to convert quantitative MS CAD results from MATLAB to DICOM-SR format. A web-based GUI based on our existing web-accessible DICOM object (WADO) image viewer has been designed to display the CAD results from generated SR files. The GUI is able to parse DICOM-SR files and extract SR document data, then display lesion volume, location, and brain matter volume along with the referenced DICOM imaging study. In addition, the GUI supports lesion contour overlay, which matches a detected MS lesion with its corresponding DICOM-SR data when a user selects either the lesion or the data. The methodology of converting CAD data in native MATLAB format to DICOM-SR and displaying the tabulated DICOM-SR along with the patient's clinical information, and relevant study images in the GUI will be demonstrated. The developed SR conversion model and GUI support aim to further demonstrate how to incorporate CAD post-processing components in a PACS and imaging informatics-based environment.

Protection of Nonhuman Primates Against Two Species of Ebola Virus Infection With a Single Complex Adenovirus Vector

DTIC Science & Technology

2010-04-01

glycoproteins of Zaire ebolavirus (ZEBOV) and Sudan ebolavirus (SEBOV) in a single complex adenovirus -based vector (CAdVax). We evaluated our vaccine ...recombinant complex adenovirus vaccine (CAdVax) system, which provides multivalent protection of NHPs against multiple species of filoviruses (33). The...CAdVax vaccine platform is based on a complex, replication-defective adenovirus 5 (Ad5) vector (28–30, 37, 38) that allows for the incorporation of

Application of virtual surgical planning with computer assisted design and manufacturing technology to cranio-maxillofacial surgery.

PubMed

Zhao, Linping; Patel, Pravin K; Cohen, Mimis

2012-07-01

Computer aided design and manufacturing (CAD/CAM) technology today is the standard in manufacturing industry. The application of the CAD/CAM technology, together with the emerging 3D medical images based virtual surgical planning (VSP) technology, to craniomaxillofacial reconstruction has been gaining increasing attention to reconstructive surgeons. This article illustrates the components, system and clinical management of the VSP and CAD/CAM technology including: data acquisition, virtual surgical and treatment planning, individual implant design and fabrication, and outcome assessment. It focuses primarily on the technical aspects of the VSP and CAD/CAM system to improve the predictability of the planning and outcome.

Bridging the integration gap between imaging and information systems: a uniform data concept for content-based image retrieval in computer-aided diagnosis.

PubMed

Welter, Petra; Riesmeier, Jörg; Fischer, Benedikt; Grouls, Christoph; Kuhl, Christiane; Deserno, Thomas M

2011-01-01

It is widely accepted that content-based image retrieval (CBIR) can be extremely useful for computer-aided diagnosis (CAD). However, CBIR has not been established in clinical practice yet. As a widely unattended gap of integration, a unified data concept for CBIR-based CAD results and reporting is lacking. Picture archiving and communication systems and the workflow of radiologists must be considered for successful data integration to be achieved. We suggest that CBIR systems applied to CAD should integrate their results in a picture archiving and communication systems environment such as Digital Imaging and Communications in Medicine (DICOM) structured reporting documents. A sample DICOM structured reporting template adaptable to CBIR and an appropriate integration scheme is presented. The proposed CBIR data concept may foster the promulgation of CBIR systems in clinical environments and, thereby, improve the diagnostic process.

Bridging the integration gap between imaging and information systems: a uniform data concept for content-based image retrieval in computer-aided diagnosis

PubMed Central

Riesmeier, Jörg; Fischer, Benedikt; Grouls, Christoph; Kuhl, Christiane; Deserno (né Lehmann), Thomas M

2011-01-01

It is widely accepted that content-based image retrieval (CBIR) can be extremely useful for computer-aided diagnosis (CAD). However, CBIR has not been established in clinical practice yet. As a widely unattended gap of integration, a unified data concept for CBIR-based CAD results and reporting is lacking. Picture archiving and communication systems and the workflow of radiologists must be considered for successful data integration to be achieved. We suggest that CBIR systems applied to CAD should integrate their results in a picture archiving and communication systems environment such as Digital Imaging and Communications in Medicine (DICOM) structured reporting documents. A sample DICOM structured reporting template adaptable to CBIR and an appropriate integration scheme is presented. The proposed CBIR data concept may foster the promulgation of CBIR systems in clinical environments and, thereby, improve the diagnostic process. PMID:21672913

BioNetCAD: design, simulation and experimental validation of synthetic biochemical networks

PubMed Central

Rialle, Stéphanie; Felicori, Liza; Dias-Lopes, Camila; Pérès, Sabine; El Atia, Sanaâ; Thierry, Alain R.; Amar, Patrick; Molina, Franck

2010-01-01

Motivation: Synthetic biology studies how to design and construct biological systems with functions that do not exist in nature. Biochemical networks, although easier to control, have been used less frequently than genetic networks as a base to build a synthetic system. To date, no clear engineering principles exist to design such cell-free biochemical networks. Results: We describe a methodology for the construction of synthetic biochemical networks based on three main steps: design, simulation and experimental validation. We developed BioNetCAD to help users to go through these steps. BioNetCAD allows designing abstract networks that can be implemented thanks to CompuBioTicDB, a database of parts for synthetic biology. BioNetCAD enables also simulations with the HSim software and the classical Ordinary Differential Equations (ODE). We demonstrate with a case study that BioNetCAD can rationalize and reduce further experimental validation during the construction of a biochemical network. Availability and implementation: BioNetCAD is freely available at http://www.sysdiag.cnrs.fr/BioNetCAD. It is implemented in Java and supported on MS Windows. CompuBioTicDB is freely accessible at http://compubiotic.sysdiag.cnrs.fr/ Contact: stephanie.rialle@sysdiag.cnrs.fr; franck.molina@sysdiag.cnrs.fr Supplementary information: Supplementary data are available at Bioinformatics online. PMID:20628073

Three dimensional display of underground water-supplying network by combining VTK with SiCAD/open GIS system

NASA Astrophysics Data System (ADS)

Chen, Shaobin; Zhang, Xubo; Wang, Wenyuan; Zhou, Chengping; Ding, Mingyue

2007-11-01

Nowadays many Geographic Information System (GIS) have been widely used in many municipal corporations. Water-supplying corporations in many cities developed GIS application system based on SiCAD/Open GIS platform several years ago for their daily management and engineering construction. With the increasing of commercial business, many corporations now need to add the functionality of three dimensional to display to their GIS System without too much financial cost. Because of the expensiveness of updating SiCAD/Open GIS system to the up-to-date version, the introduction of a third-part 3D display technology is considered. In our solution, Visualization Toolkit (VTK) is used to achieve three dimensional display of underground water-supplying network on the basis of an existing SiCAD/Open GIS system. This paper addresses on the system architecture and key implementation technologies of this solution.

Detection of Anomalous Insiders in Collaborative Environments via Relational Analysis of Access Logs

PubMed Central

Chen, You; Malin, Bradley

2014-01-01

Collaborative information systems (CIS) are deployed within a diverse array of environments, ranging from the Internet to intelligence agencies to healthcare. It is increasingly the case that such systems are applied to manage sensitive information, making them targets for malicious insiders. While sophisticated security mechanisms have been developed to detect insider threats in various file systems, they are neither designed to model nor to monitor collaborative environments in which users function in dynamic teams with complex behavior. In this paper, we introduce a community-based anomaly detection system (CADS), an unsupervised learning framework to detect insider threats based on information recorded in the access logs of collaborative environments. CADS is based on the observation that typical users tend to form community structures, such that users with low a nity to such communities are indicative of anomalous and potentially illicit behavior. The model consists of two primary components: relational pattern extraction and anomaly detection. For relational pattern extraction, CADS infers community structures from CIS access logs, and subsequently derives communities, which serve as the CADS pattern core. CADS then uses a formal statistical model to measure the deviation of users from the inferred communities to predict which users are anomalies. To empirically evaluate the threat detection model, we perform an analysis with six months of access logs from a real electronic health record system in a large medical center, as well as a publicly-available dataset for replication purposes. The results illustrate that CADS can distinguish simulated anomalous users in the context of real user behavior with a high degree of certainty and with significant performance gains in comparison to several competing anomaly detection models. PMID:25485309

A CAD system and quality assurance protocol for bone age assessment utilizing digital hand atlas

NASA Astrophysics Data System (ADS)

Gertych, Arakadiusz; Zhang, Aifeng; Ferrara, Benjamin; Liu, Brent J.

2007-03-01

Determination of bone age assessment (BAA) in pediatric radiology is a task based on detailed analysis of patient's left hand X-ray. The current standard utilized in clinical practice relies on a subjective comparison of the hand with patterns in the book atlas. The computerized approach to BAA (CBAA) utilizes automatic analysis of the regions of interest in the hand image. This procedure is followed by extraction of quantitative features sensitive to skeletal development that are further converted to a bone age value utilizing knowledge from the digital hand atlas (DHA). This also allows providing BAA results resembling current clinical approach. All developed methodologies have been combined into one CAD module with a graphical user interface (GUI). CBAA can also improve the statistical and analytical accuracy based on a clinical work-flow analysis. For this purpose a quality assurance protocol (QAP) has been developed. Implementation of the QAP helped to make the CAD more robust and find images that cannot meet conditions required by DHA standards. Moreover, the entire CAD-DHA system may gain further benefits if clinical acquisition protocol is modified. The goal of this study is to present the performance improvement of the overall CAD-DHA system with QAP and the comparison of the CAD results with chronological age of 1390 normal subjects from the DHA. The CAD workstation can process images from local image database or from a PACS server.

Mass detection in digital breast tomosynthesis: Deep convolutional neural network with transfer learning from mammography

PubMed Central

Chan, Heang-Ping; Hadjiiski, Lubomir; Helvie, Mark A.; Wei, Jun; Cha, Kenny

2016-01-01

Purpose: Develop a computer-aided detection (CAD) system for masses in digital breast tomosynthesis (DBT) volume using a deep convolutional neural network (DCNN) with transfer learning from mammograms. Methods: A data set containing 2282 digitized film and digital mammograms and 324 DBT volumes were collected with IRB approval. The mass of interest on the images was marked by an experienced breast radiologist as reference standard. The data set was partitioned into a training set (2282 mammograms with 2461 masses and 230 DBT views with 228 masses) and an independent test set (94 DBT views with 89 masses). For DCNN training, the region of interest (ROI) containing the mass (true positive) was extracted from each image. False positive (FP) ROIs were identified at prescreening by their previously developed CAD systems. After data augmentation, a total of 45 072 mammographic ROIs and 37 450 DBT ROIs were obtained. Data normalization and reduction of non-uniformity in the ROIs across heterogeneous data was achieved using a background correction method applied to each ROI. A DCNN with four convolutional layers and three fully connected (FC) layers was first trained on the mammography data. Jittering and dropout techniques were used to reduce overfitting. After training with the mammographic ROIs, all weights in the first three convolutional layers were frozen, and only the last convolution layer and the FC layers were randomly initialized again and trained using the DBT training ROIs. The authors compared the performances of two CAD systems for mass detection in DBT: one used the DCNN-based approach and the other used their previously developed feature-based approach for FP reduction. The prescreening stage was identical in both systems, passing the same set of mass candidates to the FP reduction stage. For the feature-based CAD system, 3D clustering and active contour method was used for segmentation; morphological, gray level, and texture features were extracted and merged with a linear discriminant classifier to score the detected masses. For the DCNN-based CAD system, ROIs from five consecutive slices centered at each candidate were passed through the trained DCNN and a mass likelihood score was generated. The performances of the CAD systems were evaluated using free-response ROC curves and the performance difference was analyzed using a non-parametric method. Results: Before transfer learning, the DCNN trained only on mammograms with an AUC of 0.99 classified DBT masses with an AUC of 0.81 in the DBT training set. After transfer learning with DBT, the AUC improved to 0.90. For breast-based CAD detection in the test set, the sensitivity for the feature-based and the DCNN-based CAD systems was 83% and 91%, respectively, at 1 FP/DBT volume. The difference between the performances for the two systems was statistically significant (p-value < 0.05). Conclusions: The image patterns learned from the mammograms were transferred to the mass detection on DBT slices through the DCNN. This study demonstrated that large data sets collected from mammography are useful for developing new CAD systems for DBT, alleviating the problem and effort of collecting entirely new large data sets for the new modality. PMID:27908154

A Knowledge Based Approach to VLSI CAD

DTIC Science & Technology

1983-09-01

Avail-and/or Dist ISpecial L| OI. SEICURITY CLASIIrCATION OP THIS IPA.lErllm S Daene." A KNOwLEDE BASED APPROACH TO VLSI CAD’ Louis L Steinberg and...major issues lies in building up and managing the knowledge base of oesign expertise. We expect that, as with many recent expert systems, in order to

Evolution of Geometric Sensitivity Derivatives from Computer Aided Design Models

NASA Technical Reports Server (NTRS)

Jones, William T.; Lazzara, David; Haimes, Robert

2010-01-01

The generation of design parameter sensitivity derivatives is required for gradient-based optimization. Such sensitivity derivatives are elusive at best when working with geometry defined within the solid modeling context of Computer-Aided Design (CAD) systems. Solid modeling CAD systems are often proprietary and always complex, thereby necessitating ad hoc procedures to infer parameter sensitivity. A new perspective is presented that makes direct use of the hierarchical associativity of CAD features to trace their evolution and thereby track design parameter sensitivity. In contrast to ad hoc methods, this method provides a more concise procedure following the model design intent and determining the sensitivity of CAD geometry directly to its respective defining parameters.

Integrated computer-aided design using minicomputers

NASA Technical Reports Server (NTRS)

Storaasli, O. O.

1980-01-01

Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM), a highly interactive software, has been implemented on minicomputers at the NASA Langley Research Center. CAD/CAM software integrates many formerly fragmented programs and procedures into one cohesive system; it also includes finite element modeling and analysis, and has been interfaced via a computer network to a relational data base management system and offline plotting devices on mainframe computers. The CAD/CAM software system requires interactive graphics terminals operating at a minimum of 4800 bits/sec transfer rate to a computer. The system is portable and introduces 'interactive graphics', which permits the creation and modification of models interactively. The CAD/CAM system has already produced designs for a large area space platform, a national transonic facility fan blade, and a laminar flow control wind tunnel model. Besides the design/drafting element analysis capability, CAD/CAM provides options to produce an automatic program tooling code to drive a numerically controlled (N/C) machine. Reductions in time for design, engineering, drawing, finite element modeling, and N/C machining will benefit productivity through reduced costs, fewer errors, and a wider range of configuration.

Automated extraction of knowledge for model-based diagnostics

NASA Technical Reports Server (NTRS)

Gonzalez, Avelino J.; Myler, Harley R.; Towhidnejad, Massood; Mckenzie, Frederic D.; Kladke, Robin R.

1990-01-01

The concept of accessing computer aided design (CAD) design databases and extracting a process model automatically is investigated as a possible source for the generation of knowledge bases for model-based reasoning systems. The resulting system, referred to as automated knowledge generation (AKG), uses an object-oriented programming structure and constraint techniques as well as internal database of component descriptions to generate a frame-based structure that describes the model. The procedure has been designed to be general enough to be easily coupled to CAD systems that feature a database capable of providing label and connectivity data from the drawn system. The AKG system is capable of defining knowledge bases in formats required by various model-based reasoning tools.

An interactive system for computer-aided diagnosis of breast masses.

PubMed

Wang, Xingwei; Li, Lihua; Liu, Wei; Xu, Weidong; Lederman, Dror; Zheng, Bin

2012-10-01

Although mammography is the only clinically accepted imaging modality for screening the general population to detect breast cancer, interpreting mammograms is difficult with lower sensitivity and specificity. To provide radiologists "a visual aid" in interpreting mammograms, we developed and tested an interactive system for computer-aided detection and diagnosis (CAD) of mass-like cancers. Using this system, an observer can view CAD-cued mass regions depicted on one image and then query any suspicious regions (either cued or not cued by CAD). CAD scheme automatically segments the suspicious region or accepts manually defined region and computes a set of image features. Using content-based image retrieval (CBIR) algorithm, CAD searches for a set of reference images depicting "abnormalities" similar to the queried region. Based on image retrieval results and a decision algorithm, a classification score is assigned to the queried region. In this study, a reference database with 1,800 malignant mass regions and 1,800 benign and CAD-generated false-positive regions was used. A modified CBIR algorithm with a new function of stretching the attributes in the multi-dimensional space and decision scheme was optimized using a genetic algorithm. Using a leave-one-out testing method to classify suspicious mass regions, we compared the classification performance using two CBIR algorithms with either equally weighted or optimally stretched attributes. Using the modified CBIR algorithm, the area under receiver operating characteristic curve was significantly increased from 0.865 ± 0.006 to 0.897 ± 0.005 (p < 0.001). This study demonstrated the feasibility of developing an interactive CAD system with a large reference database and achieving improved performance.

Use of CAD systems in design of Space Station and space robots

NASA Technical Reports Server (NTRS)

Dwivedi, Suren N.; Yadav, P.; Jones, Gary; Travis, Elmer W.

1988-01-01

The evolution of CAD systems is traced. State-of-the-art CAD systems are reviewed and various advanced CAD facilities and supplementing systems being used at NASA-Goddard are described. CAD hardware, computer software, and protocols are detailed.

CAD/CAM interface design of excimer laser micro-processing system

NASA Astrophysics Data System (ADS)

Jing, Liang; Chen, Tao; Zuo, Tiechuan

2005-12-01

Recently CAD/CAM technology has been gradually used in the field of laser processing. The excimer laser micro-processing system just identified G instruction before CAD/CAM interface was designed. However the course of designing a part with G instruction for users is too hard. The efficiency is low and probability of making errors is high. By secondary development technology of AutoCAD with Visual Basic, an application was developed to pick-up each entity's information in graph and convert them to each entity's processing parameters. Also an additional function was added into former controlling software to identify these processing parameters of each entity and realize continue processing of graphic. Based on the above CAD/CAM interface, Users can design a part in AutoCAD instead of using G instruction. The period of designing a part is sharply shortened. This new way of design greatly guarantees the processing parameters of the part is right and exclusive. The processing of complex novel bio-chip has been realized by this new function.

Surface Modeling, Solid Modeling and Finite Element Modeling. Analysis Capabilities of Computer-Assisted Design and Manufacturing Systems.

ERIC Educational Resources Information Center

Nee, John G.; Kare, Audhut P.

1987-01-01

Explores several concepts in computer assisted design/computer assisted manufacturing (CAD/CAM). Defines, evaluates, reviews and compares advanced computer-aided geometric modeling and analysis techniques. Presents the results of a survey to establish the capabilities of minicomputer based-systems with the CAD/CAM packages evaluated. (CW)

ACSYNT - A standards-based system for parametric, computer aided conceptual design of aircraft

NASA Technical Reports Server (NTRS)

Jayaram, S.; Myklebust, A.; Gelhausen, P.

1992-01-01

A group of eight US aerospace companies together with several NASA and NAVY centers, led by NASA Ames Systems Analysis Branch, and Virginia Tech's CAD Laboratory agreed, through the assistance of Americal Technology Initiative, in 1990 to form the ACSYNT (Aircraft Synthesis) Institute. The Institute is supported by a Joint Sponsored Research Agreement to continue the research and development in computer aided conceptual design of aircraft initiated by NASA Ames Research Center and Virginia Tech's CAD Laboratory. The result of this collaboration, a feature-based, parametric computer aided aircraft conceptual design code called ACSYNT, is described. The code is based on analysis routines begun at NASA Ames in the early 1970's. ACSYNT's CAD system is based entirely on the ISO standard Programmer's Hierarchical Interactive Graphics System and is graphics-device independent. The code includes a highly interactive graphical user interface, automatically generated Hermite and B-Spline surface models, and shaded image displays. Numerous features to enhance aircraft conceptual design are described.

The 28-entity IGES test file results using ComputerVision CADDS 4X

NASA Technical Reports Server (NTRS)

Kuan, Anchyi; Shah, Saurin; Smith, Kevin

1987-01-01

The investigation was based on the following steps: (1) Read the 28 Entity IGES (Initial Graphics Exchange Specification) Test File into the CAD data base with the IGES post-processor; (2) Make the modifications to the displayed geometries, which should produce the normalized front view and the drawing entity defined display; (3) Produce the drawing entity defined display of the file as it appears in the CAD system after modification to the geometry; (4) Translate the file back to IGES format using IGES pre-processor; (5) Read the IGES file produced by the pre-processor back into the CAD data base; (6) Produce another drawing entity defined display of the CAD display; and (7) Compare the plots resulting from steps 3 and 6 - they should be identical to each other.

Convolutional neural network based deep-learning architecture for prostate cancer detection on multiparametric magnetic resonance images

NASA Astrophysics Data System (ADS)

Tsehay, Yohannes K.; Lay, Nathan S.; Roth, Holger R.; Wang, Xiaosong; Kwak, Jin Tae; Turkbey, Baris I.; Pinto, Peter A.; Wood, Brad J.; Summers, Ronald M.

2017-03-01

Prostate cancer (PCa) is the second most common cause of cancer related deaths in men. Multiparametric MRI (mpMRI) is the most accurate imaging method for PCa detection; however, it requires the expertise of experienced radiologists leading to inconsistency across readers of varying experience. To increase inter-reader agreement and sensitivity, we developed a computer-aided detection (CAD) system that can automatically detect lesions on mpMRI that readers can use as a reference. We investigated a convolutional neural network based deep-learing (DCNN) architecture to find an improved solution for PCa detection on mpMRI. We adopted a network architecture from a state-of-the-art edge detector that takes an image as an input and produces an image probability map. Two-fold cross validation along with a receiver operating characteristic (ROC) analysis and free-response ROC (FROC) were used to determine our deep-learning based prostate-CAD's (CADDL) performance. The efficacy was compared to an existing prostate CAD system that is based on hand-crafted features, which was evaluated on the same test-set. CADDL had an 86% detection rate at 20% false-positive rate while the top-down learning CAD had 80% detection rate at the same false-positive rate, which translated to 94% and 85% detection rate at 10 false-positives per patient on the FROC. A CNN based CAD is able to detect cancerous lesions on mpMRI of the prostate with results comparable to an existing prostate-CAD showing potential for further development.

Diagnostic performance of an acoustic-based system for coronary artery disease risk stratification.

PubMed

Winther, Simon; Nissen, Louise; Schmidt, Samuel Emil; Westra, Jelmer Sybren; Rasmussen, Laust Dupont; Knudsen, Lars Lyhne; Madsen, Lene Helleskov; Kirk Johansen, Jane; Larsen, Bjarke Skogstad; Struijk, Johannes Jan; Frost, Lars; Holm, Niels Ramsing; Christiansen, Evald Høj; Botker, Hans Erik; Bøttcher, Morten

2018-06-01

Diagnosing coronary artery disease (CAD) continues to require substantial healthcare resources. Acoustic analysis of transcutaneous heart sounds of cardiac movement and intracoronary turbulence due to obstructive coronary disease could potentially change this. The aim of this study was thus to test the diagnostic accuracy of a new portable acoustic device for detection of CAD. We included 1675 patients consecutively with low to intermediate likelihood of CAD who had been referred for cardiac CT angiography. If significant obstruction was suspected in any coronary segment, patients were referred to invasive angiography and fractional flow reserve (FFR) assessment. Heart sound analysis was performed in all patients. A predefined acoustic CAD-score algorithm was evaluated; subsequently, we developed and validated an updated CAD-score algorithm that included both acoustic features and clinical risk factors. Low risk is indicated by a CAD-score value ≤20. Haemodynamically significant CAD assessed from FFR was present in 145 (10.0%) patients. In the entire cohort, the predefined CAD-score had a sensitivity of 63% and a specificity of 44%. In total, 50% had an updated CAD-score value ≤20. At this cut-off, sensitivity was 81% (95% CI 73% to 87%), specificity 53% (95% CI 50% to 56%), positive predictive value 16% (95% CI 13% to 18%) and negative predictive value 96% (95% CI 95% to 98%) for diagnosing haemodynamically significant CAD. Sound-based detection of CAD enables risk stratification superior to clinical risk scores. With a negative predictive value of 96%, this new acoustic rule-out system could potentially supplement clinical assessment to guide decisions on the need for further diagnostic investigation. ClinicalTrials.gov identifier NCT02264717; Results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Potential clinical impact of advanced imaging and computer-aided diagnosis in chest radiology: importance of radiologist's role and successful observer study.

PubMed

Li, Feng

2015-07-01

This review paper is based on our research experience in the past 30 years. The importance of radiologists' role is discussed in the development or evaluation of new medical images and of computer-aided detection (CAD) schemes in chest radiology. The four main topics include (1) introducing what diseases can be included in a research database for different imaging techniques or CAD systems and what imaging database can be built by radiologists, (2) understanding how radiologists' subjective judgment can be combined with technical objective features to improve CAD performance, (3) sharing our experience in the design of successful observer performance studies, and (4) finally, discussing whether the new images and CAD systems can improve radiologists' diagnostic ability in chest radiology. In conclusion, advanced imaging techniques and detection/classification of CAD systems have a potential clinical impact on improvement of radiologists' diagnostic ability, for both the detection and the differential diagnosis of various lung diseases, in chest radiology.

CAD/CAM complete dentures: a review of two commercial fabrication systems.

PubMed

Kattadiyil, Mathew T; Goodacre, Charles J; Baba, Nadim Z

2013-06-01

The use of computer-aided design and computer-aided manufacturing (CAD/CAM) has become available for complete dentures through the AvaDent and Dentca systems. AvaDent uses laser scanning and computer technology. Teeth are arranged and bases formed using proprietary software.The bases are milled from prepolymerized pucks of resin. Dentca uses computer software to produce virtual maxillary and mandibular edentulous ridges, arrange the teeth and form bases. The dentures are fabricated using a conventional processing technique.

An esthetics rehabilitation with computer-aided design/ computer-aided manufacturing technology.

PubMed

Mazaro, Josá Vitor Quinelli; de Mello, Caroline Cantieri; Zavanelli, Adriana Cristina; Santiago, Joel Ferreira; Amoroso, Andressa Paschoal; Pellizzer, Eduardo Piza

2014-07-01

This paper describes a case of a rehabilitation involving Computer Aided Design/Computer Aided Manufacturing (CAD-CAM) system in implant supported and dental supported prostheses using zirconia as framework. The CAD-CAM technology has developed considerably over last few years, becoming a reality in dental practice. Among the widely used systems are the systems based on zirconia which demonstrate important physical and mechanical properties of high strength, adequate fracture toughness, biocompatibility and esthetics, and are indicated for unitary prosthetic restorations and posterior and anterior framework. All the modeling was performed by using CAD-CAM system and prostheses were cemented using resin cement best suited for each situation. The rehabilitation of the maxillary arch using zirconia framework demonstrated satisfactory esthetic and functional results after a 12-month control and revealed no biological and technical complications. This article shows the important of use technology CAD/CAM in the manufacture of dental prosthesis and implant-supported.

[Coloration of mica glass ceramic for use in dental CAD/CAM system].

PubMed

Sun, Ying; Wang, Zhong-yi; Tian, Jie-mo; Cao, Xiao-gang

2003-03-01

An intrinsically colored machinable glass-ceramic containing tetrasilicic fluormica as the predominant crystal phase was studied, which was used in molar crown in dental CAD/CAM system. Orthogonal design analysis was used to select appropriate base formula, coloration and heat treatment process. Factors influencing the color appearance of mica glass ceramic were nucleation agent and the ratio of Mg(2+) to K(+) in base formula; Cerium oxide (CeO(2)) was used as the main coloration; The preferred heat treatment was 650 degrees C for 1 h and 1,000 degrees C or 1,050 degrees C for 3 h - 4 h. This mica glass-ceramic could provide 4 to 5 color appearance for dental use, it showed excellent machinability which was eminently suitable for use in dental CAD/CAM system.

CAPRI (Computational Analysis PRogramming Interface): A Solid Modeling Based Infra-Structure for Engineering Analysis and Design Simulations

NASA Technical Reports Server (NTRS)

Haimes, Robert; Follen, Gregory J.

1998-01-01

CAPRI is a CAD-vendor neutral application programming interface designed for the construction of analysis and design systems. By allowing access to the geometry from within all modules (grid generators, solvers and post-processors) such tasks as meshing on the actual surfaces, node enrichment by solvers and defining which mesh faces are boundaries (for the solver and visualization system) become simpler. The overall reliance on file 'standards' is minimized. This 'Geometry Centric' approach makes multi-physics (multi-disciplinary) analysis codes much easier to build. By using the shared (coupled) surface as the foundation, CAPRI provides a single call to interpolate grid-node based data from the surface discretization in one volume to another. Finally, design systems are possible where the results can be brought back into the CAD system (and therefore manufactured) because all geometry construction and modification are performed using the CAD system's geometry kernel.

CAD Services: an Industry Standard Interface for Mechanical CAD Interoperability

NASA Technical Reports Server (NTRS)

Claus, Russell; Weitzer, Ilan

2002-01-01

Most organizations seek to design and develop new products in increasingly shorter time periods. At the same time, increased performance demands require a team-based multidisciplinary design process that may span several organizations. One approach to meet these demands is to use 'Geometry Centric' design. In this approach, design engineers team their efforts through one united representation of the design that is usually captured in a CAD system. Standards-based interfaces are critical to provide uniform, simple, distributed services that enable the 'Geometry Centric' design approach. This paper describes an industry-wide effort, under the Object Management Group's (OMG) Manufacturing Domain Task Force, to define interfaces that enable the interoperability of CAD, Computer Aided Manufacturing (CAM), and Computer Aided Engineering (CAE) tools. This critical link to enable 'Geometry Centric' design is called: Cad Services V1.0. This paper discusses the features of this standard and proposed application.

Application programs written by using customizing tools of a computer-aided design system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, X.; Huang, R.; Juricic, D.

1995-12-31

Customizing tools of Computer-Aided Design Systems have been developed to such a degree as to become equivalent to powerful higher-level programming languages that are especially suitable for graphics applications. Two examples of application programs written by using AutoCAD`s customizing tools are given in some detail to illustrate their power. One tool uses AutoLISP list-processing language to develop an application program that produces four views of a given solid model. The other uses AutoCAD Developmental System, based on program modules written in C, to produce an application program that renders a freehand sketch from a given CAD drawing.

Marginal fit of all-ceramic crowns fabricated using two extraoral CAD/CAM systems in comparison with the conventional technique.

PubMed

Alqahtani, Fawaz

2017-01-01

The purpose of this study was to determine the effect of two extraoral computer-aided design (CAD) and computer-aided manufacturing (CAM) systems, in comparison with conventional techniques, on the marginal fit of monolithic CAD/CAM lithium disilicate ceramic crowns. This is an in vitro interventional study. The study was carried out at the Department of Prosthodontics, School of Dentistry, Prince Sattam Bin Abdul-Aziz University, Saudi Arabia, from December 2015 to April 2016. A marginal gap of 60 lithium disilicate crowns was evaluated by scanning electron microscopy. In total, 20 pressable lithium disilicate (IPS e.max Press [Ivoclar Vivadent]) ceramic crowns were fabricated using the conventional lost-wax technique as a control group. The experimental all-ceramic crowns were produced based on a scan stone model and milled using two extraoral CAD/CAM systems: the Cerec group was fabricated using the Cerec CAD/CAM system, and the Trios group was fabricated using Trios CAD and milled using Wieland Zenotec CAM. One-way analysis of variance (ANOVA) and the Scheffe post hoc test were used for statistical comparison of the groups (α=0.05). The mean (±standard deviation) of the marginal gap of each group was as follows: the Control group was 91.15 (±15.35) µm, the Cerec group was 111.07 (±6.33) µm, and the Trios group was 60.17 (±11.09) µm. One-way ANOVA and the Scheffe post hoc test showed a statistically significant difference in the marginal gap between all groups. It can be concluded from the current study that all-ceramic crowns, fabricated using the CAD/CAM system, show a marginal accuracy that is acceptable in clinical environments. The Trios CAD group displayed the smallest marginal gap.

Selection of examples in case-based computer-aided decision systems

PubMed Central

Mazurowski, Maciej A.; Zurada, Jacek M.; Tourassi, Georgia D.

2013-01-01

Case-based computer-aided decision (CB-CAD) systems rely on a database of previously stored, known examples when classifying new, incoming queries. Such systems can be particularly useful since they do not need retraining every time a new example is deposited in the case base. The adaptive nature of case-based systems is well suited to the current trend of continuously expanding digital databases in the medical domain. To maintain efficiency, however, such systems need sophisticated strategies to effectively manage the available evidence database. In this paper, we discuss the general problem of building an evidence database by selecting the most useful examples to store while satisfying existing storage requirements. We evaluate three intelligent techniques for this purpose: genetic algorithm-based selection, greedy selection and random mutation hill climbing. These techniques are compared to a random selection strategy used as the baseline. The study is performed with a previously presented CB-CAD system applied for false positive reduction in screening mammograms. The experimental evaluation shows that when the development goal is to maximize the system’s diagnostic performance, the intelligent techniques are able to reduce the size of the evidence database to 37% of the original database by eliminating superfluous and/or detrimental examples while at the same time significantly improving the CAD system’s performance. Furthermore, if the case-base size is a main concern, the total number of examples stored in the system can be reduced to only 2–4% of the original database without a decrease in the diagnostic performance. Comparison of the techniques shows that random mutation hill climbing provides the best balance between the diagnostic performance and computational efficiency when building the evidence database of the CB-CAD system. PMID:18854606

Computer-aided detection of breast masses: Four-view strategy for screening mammography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei Jun; Chan Heangping; Zhou Chuan

2011-04-15

Purpose: To improve the performance of a computer-aided detection (CAD) system for mass detection by using four-view information in screening mammography. Methods: The authors developed a four-view CAD system that emulates radiologists' reading by using the craniocaudal and mediolateral oblique views of the ipsilateral breast to reduce false positives (FPs) and the corresponding views of the contralateral breast to detect asymmetry. The CAD system consists of four major components: (1) Initial detection of breast masses on individual views, (2) information fusion of the ipsilateral views of the breast (referred to as two-view analysis), (3) information fusion of the corresponding viewsmore » of the contralateral breast (referred to as bilateral analysis), and (4) fusion of the four-view information with a decision tree. The authors collected two data sets for training and testing of the CAD system: A mass set containing 389 patients with 389 biopsy-proven masses and a normal set containing 200 normal subjects. All cases had four-view mammograms. The true locations of the masses on the mammograms were identified by an experienced MQSA radiologist. The authors randomly divided the mass set into two independent sets for cross validation training and testing. The overall test performance was assessed by averaging the free response receiver operating characteristic (FROC) curves of the two test subsets. The FP rates during the FROC analysis were estimated by using the normal set only. The jackknife free-response ROC (JAFROC) method was used to estimate the statistical significance of the difference between the test FROC curves obtained with the single-view and the four-view CAD systems. Results: Using the single-view CAD system, the breast-based test sensitivities were 58% and 77% at the FP rates of 0.5 and 1.0 per image, respectively. With the four-view CAD system, the breast-based test sensitivities were improved to 76% and 87% at the corresponding FP rates, respectively. The improvement was found to be statistically significant (p<0.0001) by JAFROC analysis. Conclusions: The four-view information fusion approach that emulates radiologists' reading strategy significantly improves the performance of breast mass detection of the CAD system in comparison with the single-view approach.« less

Study on the integration approaches to CAD/CAPP/FMS in garment CIMS

NASA Astrophysics Data System (ADS)

Wang, Xiankui; Tian, Wensheng; Liu, Chengying; Li, Zhizhong

1995-08-01

Computer integrated manufacturing system (CIMS), as an advanced methodology, has been applied in many industry fields. There is, however, little research on the application of CIMS in the garment industry, especially on the integrated approach to CAD, CAPP, and FMS in garment CIMS. In this paper, the current situations of CAD, CAPP, and FMS in the garment industry are discussed, and information requirements between them as well as the integrated approaches are also investigated. The representation of the garments' product data by the group technology coding is proposed. Based on the group technology, a shared data base as an integration element can be constructed, which leads to the integration of CAD/CAPP/FMS in garment CIMS.

Computer-aided detection in musculoskeletal projection radiography: A systematic review.

PubMed

Gundry, M; Knapp, K; Meertens, R; Meakin, J R

2018-05-01

To investigated the accuracy of computer-aided detection (CAD) software in musculoskeletal projection radiography via a systematic review. Following selection screening, eligible studies were assessed for bias, and had their study characteristics extracted resulting in 22 studies being included. Of these 22 three studies had tested their CAD software in a clinical setting; the first study investigated vertebral fractures, reporting a sensitivity score of 69.3% with CAD, compared to 59.8% sensitivity without CAD. The second study tested dental caries diagnosis producing a sensitivity score of 68.8% and specificity of 94.1% with CAD, compared to sensitivity of 39.3% and specificity of 96.7% without CAD. The third indicated osteoporotic cases based on CAD, resulting in 100% sensitivity and 81.3% specificity. The current evidence reported shows a lack of development into the clinical testing phase; however the research does show future promise in the variation of different CAD systems. Copyright © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

Case-based lung image categorization and retrieval for interstitial lung diseases: clinical workflows.

PubMed

Depeursinge, Adrien; Vargas, Alejandro; Gaillard, Frédéric; Platon, Alexandra; Geissbuhler, Antoine; Poletti, Pierre-Alexandre; Müller, Henning

2012-01-01

Clinical workflows and user interfaces of image-based computer-aided diagnosis (CAD) for interstitial lung diseases in high-resolution computed tomography are introduced and discussed. Three use cases are implemented to assist students, radiologists, and physicians in the diagnosis workup of interstitial lung diseases. In a first step, the proposed system shows a three-dimensional map of categorized lung tissue patterns with quantification of the diseases based on texture analysis of the lung parenchyma. Then, based on the proportions of abnormal and normal lung tissue as well as clinical data of the patients, retrieval of similar cases is enabled using a multimodal distance aggregating content-based image retrieval (CBIR) and text-based information search. The global system leads to a hybrid detection-CBIR-based CAD, where detection-based and CBIR-based CAD show to be complementary both on the user's side and on the algorithmic side. The proposed approach is in accordance with the classical workflow of clinicians searching for similar cases in textbooks and personal collections. The developed system enables objective and customizable inter-case similarity assessment, and the performance measures obtained with a leave-one-patient-out cross-validation (LOPO CV) are representative of a clinical usage of the system.

Coronary Artery Disease - Reporting and Data System (CAD-RADS): An Expert Consensus Document of SCCT, ACR and NASCI: Endorsed by the ACC.

PubMed

Cury, Ricardo C; Abbara, Suhny; Achenbach, Stephan; Agatston, Arthur; Berman, Daniel S; Budoff, Matthew J; Dill, Karin E; Jacobs, Jill E; Maroules, Christopher D; Rubin, Geoffrey D; Rybicki, Frank J; Schoepf, U Joseph; Shaw, Leslee J; Stillman, Arthur E; White, Charles S; Woodard, Pamela K; Leipsic, Jonathon A

2016-09-01

The intent of CAD-RADS - Coronary Artery Disease Reporting and Data System is to create a standardized method to communicate findings of coronary CT angiography (coronary CTA) in order to facilitate decision-making regarding further patient management. The suggested CAD-RADS classification is applied on a per-patient basis and represents the highest-grade coronary artery lesion documented by coronary CTA. It ranges from CAD-RADS 0 (Zero) for the complete absence of stenosis and plaque to CAD-RADS 5 for the presence of at least one totally occluded coronary artery and should always be interpreted in conjunction with the impression found in the report. Specific recommendations are provided for further management of patients with stable or acute chest pain based on the CAD-RADS classification. The main goal of CAD-RADS is to standardize reporting of coronary CTA results and to facilitate communication of test results to referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will provide a framework of standardization that may benefit education, research, peer-review and quality assurance with the potential to ultimately result in improved quality of care. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Computer aided detection of clusters of microcalcifications on full field digital mammograms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ge Jun; Sahiner, Berkman; Hadjiiski, Lubomir M.

2006-08-15

We are developing a computer-aided detection (CAD) system to identify microcalcification clusters (MCCs) automatically on full field digital mammograms (FFDMs). The CAD system includes six stages: preprocessing; image enhancement; segmentation of microcalcification candidates; false positive (FP) reduction for individual microcalcifications; regional clustering; and FP reduction for clustered microcalcifications. At the stage of FP reduction for individual microcalcifications, a truncated sum-of-squares error function was used to improve the efficiency and robustness of the training of an artificial neural network in our CAD system for FFDMs. At the stage of FP reduction for clustered microcalcifications, morphological features and features derived from themore » artificial neural network outputs were extracted from each cluster. Stepwise linear discriminant analysis (LDA) was used to select the features. An LDA classifier was then used to differentiate clustered microcalcifications from FPs. A data set of 96 cases with 192 images was collected at the University of Michigan. This data set contained 96 MCCs, of which 28 clusters were proven by biopsy to be malignant and 68 were proven to be benign. The data set was separated into two independent data sets for training and testing of the CAD system in a cross-validation scheme. When one data set was used to train and validate the convolution neural network (CNN) in our CAD system, the other data set was used to evaluate the detection performance. With the use of a truncated error metric, the training of CNN could be accelerated and the classification performance was improved. The CNN in combination with an LDA classifier could substantially reduce FPs with a small tradeoff in sensitivity. By using the free-response receiver operating characteristic methodology, it was found that our CAD system can achieve a cluster-based sensitivity of 70, 80, and 90 % at 0.21, 0.61, and 1.49 FPs/image, respectively. For case-based performance evaluation, a sensitivity of 70, 80, and 90 % can be achieved at 0.07, 0.17, and 0.65 FPs/image, respectively. We also used a data set of 216 mammograms negative for clustered microcalcifications to further estimate the FP rate of our CAD system. The corresponding FP rates were 0.15, 0.31, and 0.86 FPs/image for cluster-based detection when negative mammograms were used for estimation of FP rates.« less

Dynamic MRI-based computer aided diagnostic systems for early detection of kidney transplant rejection: A survey

NASA Astrophysics Data System (ADS)

Mostapha, Mahmoud; Khalifa, Fahmi; Alansary, Amir; Soliman, Ahmed; Gimel'farb, Georgy; El-Baz, Ayman

2013-10-01

Early detection of renal transplant rejection is important to implement appropriate medical and immune therapy in patients with transplanted kidneys. In literature, a large number of computer-aided diagnostic (CAD) systems using different image modalities, such as ultrasound (US), magnetic resonance imaging (MRI), computed tomography (CT), and radionuclide imaging, have been proposed for early detection of kidney diseases. A typical CAD system for kidney diagnosis consists of a set of processing steps including: motion correction, segmentation of the kidney and/or its internal structures (e.g., cortex, medulla), construction of agent kinetic curves, functional parameter estimation, diagnosis, and assessment of the kidney status. In this paper, we survey the current state-of-the-art CAD systems that have been developed for kidney disease diagnosis using dynamic MRI. In addition, the paper addresses several challenges that researchers face in developing efficient, fast and reliable CAD systems for the early detection of kidney diseases.

Haptic feedback improves surgeons' user experience and fracture reduction in facial trauma simulation.

PubMed

Girod, Sabine; Schvartzman, Sara C; Gaudilliere, Dyani; Salisbury, Kenneth; Silva, Rebeka

2016-01-01

Computer-assisted surgical (CAS) planning tools are available for craniofacial surgery, but are usually based on computer-aided design (CAD) tools that lack the ability to detect the collision of virtual objects (i.e., fractured bone segments). We developed a CAS system featuring a sense of touch (haptic) that enables surgeons to physically interact with individual, patient-specific anatomy and immerse in a three-dimensional virtual environment. In this study, we evaluated initial user experience with our novel system compared to an existing CAD system. Ten surgery resident trainees received a brief verbal introduction to both the haptic and CAD systems. Users simulated mandibular fracture reduction in three clinical cases within a 15 min time limit for each system and completed a questionnaire to assess their subjective experience. We compared standard landmarks and linear and angular measurements between the simulated results and the actual surgical outcome and found that haptic simulation results were not significantly different from actual postoperative outcomes. In contrast, CAD results significantly differed from both the haptic simulation and actual postoperative results. In addition to enabling a more accurate fracture repair, the haptic system provided a better user experience than the CAD system in terms of intuitiveness and self-reported quality of repair.

Computer-Aided Diagnosis Based on Convolutional Neural Network System for Colorectal Polyp Classification: Preliminary Experience.

PubMed

Komeda, Yoriaki; Handa, Hisashi; Watanabe, Tomohiro; Nomura, Takanobu; Kitahashi, Misaki; Sakurai, Toshiharu; Okamoto, Ayana; Minami, Tomohiro; Kono, Masashi; Arizumi, Tadaaki; Takenaka, Mamoru; Hagiwara, Satoru; Matsui, Shigenaga; Nishida, Naoshi; Kashida, Hiroshi; Kudo, Masatoshi

2017-01-01

Computer-aided diagnosis (CAD) is becoming a next-generation tool for the diagnosis of human disease. CAD for colon polyps has been suggested as a particularly useful tool for trainee colonoscopists, as the use of a CAD system avoids the complications associated with endoscopic resections. In addition to conventional CAD, a convolutional neural network (CNN) system utilizing artificial intelligence (AI) has been developing rapidly over the past 5 years. We attempted to generate a unique CNN-CAD system with an AI function that studied endoscopic images extracted from movies obtained with colonoscopes used in routine examinations. Here, we report our preliminary results of this novel CNN-CAD system for the diagnosis of colon polyps. A total of 1,200 images from cases of colonoscopy performed between January 2010 and December 2016 at Kindai University Hospital were used. These images were extracted from the video of actual endoscopic examinations. Additional video images from 10 cases of unlearned processes were retrospectively assessed in a pilot study. They were simply diagnosed as either an adenomatous or nonadenomatous polyp. The number of images used by AI to learn to distinguish adenomatous from nonadenomatous was 1,200:600. These images were extracted from the videos of actual endoscopic examinations. The size of each image was adjusted to 256 × 256 pixels. A 10-hold cross-validation was carried out. The accuracy of the 10-hold cross-validation is 0.751, where the accuracy is the ratio of the number of correct answers over the number of all the answers produced by the CNN. The decisions by the CNN were correct in 7 of 10 cases. A CNN-CAD system using routine colonoscopy might be useful for the rapid diagnosis of colorectal polyp classification. Further prospective studies in an in vivo setting are required to confirm the effectiveness of a CNN-CAD system in routine colonoscopy. © 2017 S. Karger AG, Basel.

Machine Learning in Ultrasound Computer-Aided Diagnostic Systems: A Survey

PubMed Central

Zhang, Fan; Li, Xuelong

2018-01-01

The ultrasound imaging is one of the most common schemes to detect diseases in the clinical practice. There are many advantages of ultrasound imaging such as safety, convenience, and low cost. However, reading ultrasound imaging is not easy. To support the diagnosis of clinicians and reduce the load of doctors, many ultrasound computer-aided diagnosis (CAD) systems are proposed. In recent years, the success of deep learning in the image classification and segmentation led to more and more scholars realizing the potential of performance improvement brought by utilizing the deep learning in the ultrasound CAD system. This paper summarized the research which focuses on the ultrasound CAD system utilizing machine learning technology in recent years. This study divided the ultrasound CAD system into two categories. One is the traditional ultrasound CAD system which employed the manmade feature and the other is the deep learning ultrasound CAD system. The major feature and the classifier employed by the traditional ultrasound CAD system are introduced. As for the deep learning ultrasound CAD, newest applications are summarized. This paper will be useful for researchers who focus on the ultrasound CAD system. PMID:29687000

Machine Learning in Ultrasound Computer-Aided Diagnostic Systems: A Survey.

PubMed

Huang, Qinghua; Zhang, Fan; Li, Xuelong

2018-01-01

The ultrasound imaging is one of the most common schemes to detect diseases in the clinical practice. There are many advantages of ultrasound imaging such as safety, convenience, and low cost. However, reading ultrasound imaging is not easy. To support the diagnosis of clinicians and reduce the load of doctors, many ultrasound computer-aided diagnosis (CAD) systems are proposed. In recent years, the success of deep learning in the image classification and segmentation led to more and more scholars realizing the potential of performance improvement brought by utilizing the deep learning in the ultrasound CAD system. This paper summarized the research which focuses on the ultrasound CAD system utilizing machine learning technology in recent years. This study divided the ultrasound CAD system into two categories. One is the traditional ultrasound CAD system which employed the manmade feature and the other is the deep learning ultrasound CAD system. The major feature and the classifier employed by the traditional ultrasound CAD system are introduced. As for the deep learning ultrasound CAD, newest applications are summarized. This paper will be useful for researchers who focus on the ultrasound CAD system.

TopoCad - A unified system for geospatial data and services

NASA Astrophysics Data System (ADS)

Felus, Y. A.; Sagi, Y.; Regev, R.; Keinan, E.

2013-10-01

"E-government" is a leading trend in public sector activities in recent years. The Survey of Israel set as a vision to provide all of its services and datasets online. The TopoCad system is the latest software tool developed in order to unify a number of services and databases into one on-line and user friendly system. The TopoCad system is based on Web 1.0 technology; hence the customer is only a consumer of data. All data and services are accessible for the surveyors and geo-information professional in an easy and comfortable way. The future lies in Web 2.0 and Web 3.0 technologies through which professionals can upload their own data for quality control and future assimilation with the national database. A key issue in the development of this complex system was to implement a simple and easy (comfortable) user experience (UX). The user interface employs natural language dialog box in order to understand the user requirements. The system then links spatial data with alpha-numeric data in a flawless manner. The operation of the TopoCad requires no user guide or training. It is intuitive and self-taught. The system utilizes semantic engines and machine understanding technologies to link records from diverse databases in a meaningful way. Thus, the next generation of TopoCad will include five main modules: users and projects information, coordinates transformations and calculations services, geospatial data quality control, linking governmental systems and databases, smart forms and applications. The article describes the first stage of the TopoCad system and gives an overview of its future development.

CAD-model-based vision for space applications

NASA Technical Reports Server (NTRS)

Shapiro, Linda G.

1988-01-01

A pose acquisition system operating in space must be able to perform well in a variety of different applications including automated guidance and inspections tasks with many different, but known objects. Since the space station is being designed with automation in mind, there will be CAD models of all the objects, including the station itself. The construction of vision models and procedures directly from the CAD models is the goal of this project. The system that is being designed and implementing must convert CAD models to vision models, predict visible features from a given view point from the vision models, construct view classes representing views of the objects, and use the view class model thus derived to rapidly determine the pose of the object from single images and/or stereo pairs.

CAD-Based Shielding Analysis for ITER Port Diagnostics

NASA Astrophysics Data System (ADS)

Serikov, Arkady; Fischer, Ulrich; Anthoine, David; Bertalot, Luciano; De Bock, Maartin; O'Connor, Richard; Juarez, Rafael; Krasilnikov, Vitaly

2017-09-01

Radiation shielding analysis conducted in support of design development of the contemporary diagnostic systems integrated inside the ITER ports is relied on the use of CAD models. This paper presents the CAD-based MCNP Monte Carlo radiation transport and activation analyses for the Diagnostic Upper and Equatorial Port Plugs (UPP #3 and EPP #8, #17). The creation process of the complicated 3D MCNP models of the diagnostics systems was substantially accelerated by application of the CAD-to-MCNP converter programs MCAM and McCad. High performance computing resources of the Helios supercomputer allowed to speed-up the MCNP parallel transport calculations with the MPI/OpenMP interface. The found shielding solutions could be universal, reducing ports R&D costs. The shield block behind the Tritium and Deposit Monitor (TDM) optical box was added to study its influence on Shut-Down Dose Rate (SDDR) in Port Interspace (PI) of EPP#17. Influence of neutron streaming along the Lost Alpha Monitor (LAM) on the neutron energy spectra calculated in the Tangential Neutron Spectrometer (TNS) of EPP#8. For the UPP#3 with Charge eXchange Recombination Spectroscopy (CXRS-core), an excessive neutron streaming along the CXRS shutter, which should be prevented in further design iteration.

Improving Perceptual Skills with 3-Dimensional Animations.

ERIC Educational Resources Information Center

Johns, Janet Faye; Brander, Julianne Marie

1998-01-01

Describes three-dimensional computer aided design (CAD) models for every component in a representative mechanical system; the CAD models made it easy to generate 3-D animations that are ideal for teaching perceptual skills in multimedia computer-based technical training. Fifteen illustrations are provided. (AEF)

Integration of a CAD System Into an MDO Framework

NASA Technical Reports Server (NTRS)

Townsend, J. C.; Samareh, J. A.; Weston, R. P.; Zorumski, W. E.

1998-01-01

NASA Langley has developed a heterogeneous distributed computing environment, called the Framework for Inter-disciplinary Design Optimization, or FIDO. Its purpose has been to demonstrate framework technical feasibility and usefulness for optimizing the preliminary design of complex systems and to provide a working environment for testing optimization schemes. Its initial implementation has been for a simplified model of preliminary design of a high-speed civil transport. Upgrades being considered for the FIDO system include a more complete geometry description, required by high-fidelity aerodynamics and structures codes and based on a commercial Computer Aided Design (CAD) system. This report presents the philosophy behind some of the decisions that have shaped the FIDO system and gives a brief case study of the problems and successes encountered in integrating a CAD system into the FEDO framework.

A feasibility study of automatic lung nodule detection in chest digital tomosynthesis with machine learning based on support vector machine

NASA Astrophysics Data System (ADS)

Lee, Donghoon; Kim, Ye-seul; Choi, Sunghoon; Lee, Haenghwa; Jo, Byungdu; Choi, Seungyeon; Shin, Jungwook; Kim, Hee-Joung

2017-03-01

The chest digital tomosynthesis(CDT) is recently developed medical device that has several advantage for diagnosing lung disease. For example, CDT provides depth information with relatively low radiation dose compared to computed tomography (CT). However, a major problem with CDT is the image artifacts associated with data incompleteness resulting from limited angle data acquisition in CDT geometry. For this reason, the sensitivity of lung disease was not clear compared to CT. In this study, to improve sensitivity of lung disease detection in CDT, we developed computer aided diagnosis (CAD) systems based on machine learning. For design CAD systems, we used 100 cases of lung nodules cropped images and 100 cases of normal lesion cropped images acquired by lung man phantoms and proto type CDT. We used machine learning techniques based on support vector machine and Gabor filter. The Gabor filter was used for extracting characteristics of lung nodules and we compared performance of feature extraction of Gabor filter with various scale and orientation parameters. We used 3, 4, 5 scales and 4, 6, 8 orientations. After extracting features, support vector machine (SVM) was used for classifying feature of lesions. The linear, polynomial and Gaussian kernels of SVM were compared to decide the best SVM conditions for CDT reconstruction images. The results of CAD system with machine learning showed the capability of automatically lung lesion detection. Furthermore detection performance was the best when Gabor filter with 5 scale and 8 orientation and SVM with Gaussian kernel were used. In conclusion, our suggested CAD system showed improving sensitivity of lung lesion detection in CDT and decide Gabor filter and SVM conditions to achieve higher detection performance of our developed CAD system for CDT.

Research on AutoCAD secondary development and function expansion based on VBA technology

NASA Astrophysics Data System (ADS)

Zhang, Runmei; Gu, Yehuan

2017-06-01

AutoCAD is the most widely used drawing tool among the similar design drawing products. In the process of drawing different types of design drawings of the same product, there are a lot of repetitive and single work contents. The traditional manual method uses a drawing software AutoCAD drawing graphics with low efficiency, high error rate and high input cost shortcomings and many more. In order to solve these problems, the design of the parametric drawing system of the hot-rolled I-beam (steel beam) cross-section is completed by using the VBA secondary development tool and the Access database software with large-capacity storage data, and the analysis of the functional extension of the plane drawing and the parametric drawing design in this paper. For the secondary development of AutoCAD functions, the system drawing work will be simplified and work efficiency also has been greatly improved. This introduction of parametric design of AutoCAD drawing system to promote the industrial mass production and related industries economic growth rate similar to the standard I-beam hot-rolled products.

Implant-supported fixed dental prostheses with CAD/CAM-fabricated porcelain crown and zirconia-based framework.

PubMed

Takaba, Masayuki; Tanaka, Shinpei; Ishiura, Yuichi; Baba, Kazuyoshi

2013-07-01

Recently, fixed dental prostheses (FDPs) with a hybrid structure of CAD/CAM porcelain crowns adhered to a CAD/CAM zirconia framework (PAZ) have been developed. The aim of this report was to describe the clinical application of a newly developed implant-supported FDP fabrication system, which uses PAZ, and to evaluate the outcome after a maximum application period of 36 months. Implants were placed in three patients with edentulous areas in either the maxilla or mandible. After the implant fixtures had successfully integrated with bone, gold-platinum alloy or zirconia custom abutments were first fabricated. Zirconia framework wax-up was performed on the custom abutments, and the CAD/CAM zirconia framework was prepared using the CAD/CAM system. Next, wax-up was performed on working models for porcelain crown fabrication, and CAD/CAM porcelain crowns were fabricated. The CAD/CAM zirconia frameworks and CAD/CAM porcelain crowns were bonded using adhesive resin cement, and the PAZ was cemented. Cementation of the implant superstructure improved the esthetics and masticatory efficiency in all patients. No undesirable outcomes, such as superstructure chipping, stomatognathic dysfunction, or periimplant bone resorption, were observed in any of the patients. PAZ may be a potential solution for ceramic-related clinical problems such as chipping and fracture and associated complicated repair procedures in implant-supported FDPs. © 2012 by the American College of Prosthodontists.

CAD-RADS(TM) Coronary Artery Disease - Reporting and Data System. An expert consensus document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Radiology (ACR) and the North American Society for Cardiovascular Imaging (NASCI). Endorsed by the American College of Cardiology.

PubMed

Cury, Ricardo C; Abbara, Suhny; Achenbach, Stephan; Agatston, Arthur; Berman, Daniel S; Budoff, Matthew J; Dill, Karin E; Jacobs, Jill E; Maroules, Christopher D; Rubin, Geoffrey D; Rybicki, Frank J; Schoepf, U Joseph; Shaw, Leslee J; Stillman, Arthur E; White, Charles S; Woodard, Pamela K; Leipsic, Jonathon A

2016-01-01

The intent of CAD-RADS - Coronary Artery Disease Reporting and Data System is to create a standardized method to communicate findings of coronary CT angiography (coronary CTA) in order to facilitate decision-making regarding further patient management. The suggested CAD-RADS classification is applied on a per-patient basis and represents the highest-grade coronary artery lesion documented by coronary CTA. It ranges from CAD-RADS 0 (Zero) for the complete absence of stenosis and plaque to CAD-RADS 5 for the presence of at least one totally occluded coronary artery and should always be interpreted in conjunction with the impression found in the report. Specific recommendations are provided for further management of patients with stable or acute chest pain based on the CAD-RADS classification. The main goal of CAD-RADS is to standardize reporting of coronary CTA results and to facilitate communication of test results to referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will provide a framework of standardization that may benefit education, research, peer-review and quality assurance with the potential to ultimately result in improved quality of care. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

High-performance computer aided detection system for polyp detection in CT colonography with fluid and fecal tagging

NASA Astrophysics Data System (ADS)

Liu, Jiamin; Wang, Shijun; Kabadi, Suraj; Summers, Ronald M.

2009-02-01

CT colonography (CTC) is a feasible and minimally invasive method for the detection of colorectal polyps and cancer screening. Computer-aided detection (CAD) of polyps has improved consistency and sensitivity of virtual colonoscopy interpretation and reduced interpretation burden. A CAD system typically consists of four stages: (1) image preprocessing including colon segmentation; (2) initial detection generation; (3) feature selection; and (4) detection classification. In our experience, three existing problems limit the performance of our current CAD system. First, highdensity orally administered contrast agents in fecal-tagging CTC have scatter effects on neighboring tissues. The scattering manifests itself as an artificial elevation in the observed CT attenuation values of the neighboring tissues. This pseudo-enhancement phenomenon presents a problem for the application of computer-aided polyp detection, especially when polyps are submerged in the contrast agents. Second, general kernel approach for surface curvature computation in the second stage of our CAD system could yield erroneous results for thin structures such as small (6-9 mm) polyps and for touching structures such as polyps that lie on haustral folds. Those erroneous curvatures will reduce the sensitivity of polyp detection. The third problem is that more than 150 features are selected from each polyp candidate in the third stage of our CAD system. These high dimensional features make it difficult to learn a good decision boundary for detection classification and reduce the accuracy of predictions. Therefore, an improved CAD system for polyp detection in CTC data is proposed by introducing three new techniques. First, a scale-based scatter correction algorithm is applied to reduce pseudo-enhancement effects in the image pre-processing stage. Second, a cubic spline interpolation method is utilized to accurately estimate curvatures for initial detection generation. Third, a new dimensionality reduction classifier, diffusion map and local linear embedding (DMLLE), is developed for classification and false positives (FP) reduction. Performance of the improved CAD system is evaluated and compared with our existing CAD system (without applying those techniques) using CT scans of 1186 patients. These scans are divided into a training set and a test set. The sensitivity of the improved CAD system increased 18% on training data at a rate of 5 FPs per patient and 15% on test data at a rate of 5 FPs per patient. Our results indicated that the improved CAD system achieved significantly better performance on medium-sized colonic adenomas with higher sensitivity and lower FP rate in CTC.

Computer-Aided Diagnosis System for Alzheimer's Disease Using Different Discrete Transform Techniques.

PubMed

Dessouky, Mohamed M; Elrashidy, Mohamed A; Taha, Taha E; Abdelkader, Hatem M

2016-05-01

The different discrete transform techniques such as discrete cosine transform (DCT), discrete sine transform (DST), discrete wavelet transform (DWT), and mel-scale frequency cepstral coefficients (MFCCs) are powerful feature extraction techniques. This article presents a proposed computer-aided diagnosis (CAD) system for extracting the most effective and significant features of Alzheimer's disease (AD) using these different discrete transform techniques and MFCC techniques. Linear support vector machine has been used as a classifier in this article. Experimental results conclude that the proposed CAD system using MFCC technique for AD recognition has a great improvement for the system performance with small number of significant extracted features, as compared with the CAD system based on DCT, DST, DWT, and the hybrid combination methods of the different transform techniques. © The Author(s) 2015.

Computer-aided mass detection in mammography: False positive reduction via gray-scale invariant ranklet texture features

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masotti, Matteo; Lanconelli, Nico; Campanini, Renato

In this work, gray-scale invariant ranklet texture features are proposed for false positive reduction (FPR) in computer-aided detection (CAD) of breast masses. Two main considerations are at the basis of this proposal. First, false positive (FP) marks surviving our previous CAD system seem to be characterized by specific texture properties that can be used to discriminate them from masses. Second, our previous CAD system achieves invariance to linear/nonlinear monotonic gray-scale transformations by encoding regions of interest into ranklet images through the ranklet transform, an image transformation similar to the wavelet transform, yet dealing with pixels' ranks rather than with theirmore » gray-scale values. Therefore, the new FPR approach proposed herein defines a set of texture features which are calculated directly from the ranklet images corresponding to the regions of interest surviving our previous CAD system, hence, ranklet texture features; then, a support vector machine (SVM) classifier is used for discrimination. As a result of this approach, texture-based information is used to discriminate FP marks surviving our previous CAD system; at the same time, invariance to linear/nonlinear monotonic gray-scale transformations of the new CAD system is guaranteed, as ranklet texture features are calculated from ranklet images that have this property themselves by construction. To emphasize the gray-scale invariance of both the previous and new CAD systems, training and testing are carried out without any in-between parameters' adjustment on mammograms having different gray-scale dynamics; in particular, training is carried out on analog digitized mammograms taken from a publicly available digital database, whereas testing is performed on full-field digital mammograms taken from an in-house database. Free-response receiver operating characteristic (FROC) curve analysis of the two CAD systems demonstrates that the new approach achieves a higher reduction of FP marks when compared to the previous one. Specifically, at 60%, 65%, and 70% per-mammogram sensitivity, the new CAD system achieves 0.50, 0.68, and 0.92 FP marks per mammogram, whereas at 70%, 75%, and 80% per-case sensitivity it achieves 0.37, 0.48, and 0.71 FP marks per mammogram, respectively. Conversely, at the same sensitivities, the previous CAD system reached 0.71, 0.87, and 1.15 FP marks per mammogram, and 0.57, 0.73, and 0.92 FPs per mammogram. Also, statistical significance of the difference between the two per-mammogram and per-case FROC curves is demonstrated by the p-value<0.001 returned by jackknife FROC analysis performed on the two CAD systems.« less

Phylogeny and expression profiling of CAD and CAD-like genes in hybrid Populus (P. deltoides × P. nigra): evidence from herbivore damage for subfunctionalization and functional divergence

PubMed Central

2010-01-01

Background Cinnamyl Alcohol Dehydrogenase (CAD) proteins function in lignin biosynthesis and play a critical role in wood development and plant defense against stresses. Previous phylogenetic studies did not include genes from seedless plants and did not reflect the deep evolutionary history of this gene family. We reanalyzed the phylogeny of CAD and CAD-like genes using a representative dataset including lycophyte and bryophyte sequences. Many CAD/CAD-like genes do not seem to be associated with wood development under normal growth conditions. To gain insight into the functional evolution of CAD/CAD-like genes, we analyzed their expression in Populus plant tissues in response to feeding damage by gypsy moth larvae (Lymantria dispar L.). Expression of CAD/CAD-like genes in Populus tissues (xylem, leaves, and barks) was analyzed in herbivore-treated and non-treated plants by real time quantitative RT-PCR. Results CAD family genes were distributed in three classes based on sequence conservation. All the three classes are represented by seedless as well as seed plants, including the class of bona fide lignin pathway genes. The expression of some CAD/CAD-like genes that are not associated with xylem development were induced following herbivore damage in leaves, while other genes were induced in only bark or xylem tissues. Five of the CAD/CAD-like genes, however, showed a shift in expression from one tissue to another between non-treated and herbivore-treated plants. Systemic expression of the CAD/CAD-like genes was generally suppressed. Conclusions Our results indicated a correlation between the evolution of the CAD gene family and lignin and that the three classes of genes may have evolved in the ancestor of land plants. Our results also suggest that the CAD/CAD-like genes have evolved a diversity of expression profiles and potentially different functions, but that they are nonetheless co-regulated under stress conditions. PMID:20509918

Wind Turbine Blade CAD Models Used as Scaffolding Technique to Teach Design Engineers

ERIC Educational Resources Information Center

Irwin, John

2013-01-01

The Siemens PLM CAD software NX is commonly used for designing mechanical systems, and in complex systems such as the emerging area of wind power, the ability to have a model controlled by design parameters is a certain advantage. Formula driven expressions based on the amount of available wind in an area can drive the amount of effective surface…

WE-E-217A-02: Methodologies for Evaluation of Standalone CAD System Performance.

PubMed

Sahiner, B

2012-06-01

Standalone performance evaluation of a CAD system provides information about the abnormality detection or classification performance of the computerized system alone. Although the performance of the reader with CAD is the final step in CAD system assessment, standalone performance evaluation is an important component for several reasons: First, standalone evaluation informs the reader about the performance level of the CAD system and may have an impact on how the reader uses the system. Second, it provides essential information to the system designer for algorithm optimization during system development. Third, standalone evaluation can provide a detailed description of algorithm performance (e.g., on subgroups of the population) because a larger data set with more samples from different subgroups can be included in standalone studies compared to reader studies. Proper standalone evaluation of a CAD system involves a number of key components, some of which are shared with the assessment of reader performance with CAD. These include (1) selection of a test data set that allows performance assessment with little or no bias and acceptable uncertainty; (2) a reference standard that indicates disease status as well as the location and extent of disease; (3) a clearly defined method for labeling each CAD mark as a true-positive or false-positive; and (4) a properly selected set of metrics to summarize the accuracy of the computer marks and their corresponding scores. In this lecture, we will discuss various approaches for the key components of standalone CAD performance evaluation listed above, and present some of the recommendations and opinions from the AAPM CAD subcommittee on these issues. Learning Objectives 1. Identify basic components and metrics in the assessment of standalone CAD systems 2. Understand how each component may affect the assessed performance 3. Learn about AAPM CAD subcommittee's opinions and recommendations on factors and metrics related to the evaluation of standalone CAD system performance. © 2012 American Association of Physicists in Medicine.

Automated knowledge base development from CAD/CAE databases

NASA Technical Reports Server (NTRS)

Wright, R. Glenn; Blanchard, Mary

1988-01-01

Knowledge base development requires a substantial investment in time, money, and resources in order to capture the knowledge and information necessary for anything other than trivial applications. This paper addresses a means to integrate the design and knowledge base development process through automated knowledge base development from CAD/CAE databases and files. Benefits of this approach include the development of a more efficient means of knowledge engineering, resulting in the timely creation of large knowledge based systems that are inherently free of error.

CAD/CAM produces dentures with improved fit.

PubMed

Steinmassl, Otto; Dumfahrt, Herbert; Grunert, Ingrid; Steinmassl, Patricia-Anca

2018-02-22

Resin polymerisation shrinkage reduces the congruence of the denture base with denture-bearing tissues and thereby decreases the retention of conventionally fabricated dentures. CAD/CAM denture manufacturing is a subtractive process, and polymerisation shrinkage is not an issue anymore. Therefore, CAD/CAM dentures are assumed to show a higher denture base congruence than conventionally fabricated dentures. It has been the aim of this study to test this hypothesis. CAD/CAM dentures provided by four different manufacturers (AvaDent, Merz Dental, Whole You, Wieland/Ivoclar) were generated from ten different master casts. Ten conventional dentures (pack and press, long-term heat polymerisation) made from the same master casts served as control group. The master casts and all denture bases were scanned and matched digitally. The absolute incongruences were measured using a 2-mm mesh. Conventionally fabricated dentures showed a mean deviation of 0.105 mm, SD = 0.019 from the master cast. All CAD/CAM dentures showed lower mean incongruences. From all CAD/CAM dentures, AvaDent Digital Dentures showed the highest congruence with the master cast surface with a mean deviation of 0.058 mm, SD = 0.005. Wieland Digital Dentures showed a mean deviation of 0.068 mm, SD = 0.005, Whole You Nexteeth prostheses showed a mean deviation of 0.074 mm, SD = 0.011 and Baltic Denture System prostheses showed a mean deviation of 0.086 mm, SD = 0.012. CAD/CAM produces dentures with better fit than conventional dentures. The present study explains the clinically observed enhanced retention and lower traumatic ulcer-frequency in CAD/CAM dentures.

Combining Feature Extraction Methods to Assist the Diagnosis of Alzheimer's Disease.

PubMed

Segovia, F; Górriz, J M; Ramírez, J; Phillips, C

2016-01-01

Neuroimaging data as (18)F-FDG PET is widely used to assist the diagnosis of Alzheimer's disease (AD). Looking for regions with hypoperfusion/ hypometabolism, clinicians may predict or corroborate the diagnosis of the patients. Modern computer aided diagnosis (CAD) systems based on the statistical analysis of whole neuroimages are more accurate than classical systems based on quantifying the uptake of some predefined regions of interests (ROIs). In addition, these new systems allow determining new ROIs and take advantage of the huge amount of information comprised in neuroimaging data. A major branch of modern CAD systems for AD is based on multivariate techniques, which analyse a neuroimage as a whole, considering not only the voxel intensities but also the relations among them. In order to deal with the vast dimensionality of the data, a number of feature extraction methods have been successfully applied. In this work, we propose a CAD system based on the combination of several feature extraction techniques. First, some commonly used feature extraction methods based on the analysis of the variance (as principal component analysis), on the factorization of the data (as non-negative matrix factorization) and on classical magnitudes (as Haralick features) were simultaneously applied to the original data. These feature sets were then combined by means of two different combination approaches: i) using a single classifier and a multiple kernel learning approach and ii) using an ensemble of classifier and selecting the final decision by majority voting. The proposed approach was evaluated using a labelled neuroimaging database along with a cross validation scheme. As conclusion, the proposed CAD system performed better than approaches using only one feature extraction technique. We also provide a fair comparison (using the same database) of the selected feature extraction methods.

Do CAD/CAM dentures really release less monomer than conventional dentures?

PubMed

Steinmassl, Patricia-Anca; Wiedemair, Verena; Huck, Christian; Klaunzer, Florian; Steinmassl, Otto; Grunert, Ingrid; Dumfahrt, Herbert

2017-06-01

Computer-aided design (CAD)/computer-aided manufacturing (CAM) dentures are assumed to have more favourable material properties than conventionally fabricated dentures, among them a lower methacrylate monomer release. The aim of this study was to test this hypothesis. CAD/CAM dentures were generated from ten different master casts by using four different CAD/CAM systems. Conventional, heat-polymerised dentures served as control group. Denture weight and volume were measured; the density was calculated, and the denture surface area was assessed digitally. The monomer release after 7 days of water storage was measured by high-performance liquid chromatography. Whole You Nexteeth and Wieland Digital Dentures had significantly lower mean volume and weight than conventional dentures. Baltic Denture System and Whole You Nexteeth had a significantly increased density. Baltic Denture System had a significantly smaller surface area. None of the CAD/CAM dentures released significantly less monomer than the control group. All tested dentures released very low amounts of methacrylate monomer, but not significantly less than conventional dentures. A statistically significant difference might nevertheless exist in comparison to other, less recommendable denture base materials, such as the frequently used autopolymerising resins. CAD/CAM denture fabrication has numerous advantages. It enables the fabrication of dentures with lower resin volume and lower denture weight. Both could increase the patient comfort. Dentures with higher density might exhibit more favourable mechanical properties. The hypothesis that CAD/CAM dentures release less monomer than conventional dentures could, however, not be verified.

Marginal fit of all-ceramic crowns fabricated using two extraoral CAD/CAM systems in comparison with the conventional technique

PubMed Central

Alqahtani, Fawaz

2017-01-01

Objective The purpose of this study was to determine the effect of two extraoral computer-aided design (CAD) and computer-aided manufacturing (CAM) systems, in comparison with conventional techniques, on the marginal fit of monolithic CAD/CAM lithium disilicate ceramic crowns. Study design This is an in vitro interventional study. Place and duration of study The study was carried out at the Department of Prosthodontics, School of Dentistry, Prince Sattam Bin Abdul-Aziz University, Saudi Arabia, from December 2015 to April 2016. Methodology A marginal gap of 60 lithium disilicate crowns was evaluated by scanning electron microscopy. In total, 20 pressable lithium disilicate (IPS e.max Press [Ivoclar Vivadent]) ceramic crowns were fabricated using the conventional lost-wax technique as a control group. The experimental all-ceramic crowns were produced based on a scan stone model and milled using two extraoral CAD/CAM systems: the Cerec group was fabricated using the Cerec CAD/CAM system, and the Trios group was fabricated using Trios CAD and milled using Wieland Zenotec CAM. One-way analysis of variance (ANOVA) and the Scheffe post hoc test were used for statistical comparison of the groups (α=0.05). Results The mean (±standard deviation) of the marginal gap of each group was as follows: the Control group was 91.15 (±15.35) µm, the Cerec group was 111.07 (±6.33) µm, and the Trios group was 60.17 (±11.09) µm. One-way ANOVA and the Scheffe post hoc test showed a statistically significant difference in the marginal gap between all groups. Conclusion It can be concluded from the current study that all-ceramic crowns, fabricated using the CAD/CAM system, show a marginal accuracy that is acceptable in clinical environments. The Trios CAD group displayed the smallest marginal gap. PMID:28352204

Computer-aided detection (CAD) of breast cancer on full field digital and screening film mammograms

NASA Astrophysics Data System (ADS)

Sun, Xuejun; Qian, Wei; Song, Xiaoshan; Qian, Yuyan; Song, Dansheng; Clark, Robert A.

2003-05-01

Full-field digital mammography (FFDM) as a new breast imaging modality has potential to detect more breast cancers or to detect them at smaller sizes and earlier stages compared with screening film mammography (SFM). However, its performance needs verification, and it would pose new problems for the development of CAD methods for breast cancer detection and diagnosis. Performance evaluation of CAD systems on FFDM and SFM has been conducted in this study, respectively. First, an adaptive CAD system employing a series of advanced modules has been developed on FFDM. Second, a standardization approach has been developed to make the CAD system independent of characteristics of digitizer or imaging modalities for mammography. CAD systems developed previously for SFM and developed in this study for FFDM have been evaluated on FFDM and SFM images without and with standardization, respectively, to examine the performance improvement of the CAD system developed in this study. Computerized free-response receiver operating characteristic (FROC) analysis has been adopted as performance evaluation method. Compared with previous one, the CAD system developed in this study demonstrated significantly performance improvements. However, the comparison results have shown that the performances of final CAD system in this study are not significantly different on FFDM and on SFM after standardization. It needs further study on the assessment of CAD system performance on FFDM and SFM modalities.

When and why might a Computer Aided Detection (CAD) system interfere with visual search? An eye-tracking study

PubMed Central

Drew, Trafton; Cunningham, Corbin; Wolfe, Jeremy

2012-01-01

Rational and Objectives Computer Aided Detection (CAD) systems are intended to improve performance. This study investigates how CAD might actually interfere with a visual search task. This is a laboratory study with implications for clinical use of CAD. Methods 47 naïve observers in two studies were asked to search for a target, embedded in 1/f2.4 noise while we monitored their eye-movements. For some observers, a CAD system marked 75% of targets and 10% of distractors while other observers completed the study without CAD. In Experiment 1, the CAD system’s primary function was to tell observers where the target might be. In Experiment 2, CAD provided information about target identity. Results In Experiment 1, there was a significant enhancement of observer sensitivity in the presence of CAD (t(22)=4.74, p<.001), but there was also a substantial cost. Targets that were not marked by the CAD system were missed more frequently than equivalent targets in No CAD blocks of the experiment (t(22)=7.02, p<.001). Experiment 2 showed no behavioral benefit from CAD, but also no significant cost on sensitivity to unmarked targets (t(22)=0.6, p=n.s.). Finally, in both experiments, CAD produced reliable changes in eye-movements: CAD observers examined a lower total percentage of the search area than the No CAD observers (Ex 1: t(48)=3.05, p<.005; Ex 2: t(50)=7.31, p<.001). Conclusions CAD signals do not combine with observers’ unaided performance in a straight-forward manner. CAD can engender a sense of certainty that can lead to incomplete search and elevated chances of missing unmarked stimuli. PMID:22958720

The influence of polishing techniques on pre-polymerized CAD\\CAM acrylic resin denture bases

PubMed Central

Alammari, Manal Rahma

2017-01-01

Background Lately, computer-aided design and computer-aided manufacturing (CAD/CAM) has broadly been successfully employed in dentistry. The CAD/CAM systems have recently become commercially available for fabrication of complete dentures, and are considered as an alternative technique to conventionally processed acrylic resin bases. However, they have not yet been fully investigated. Objective The purpose of this study was to inspect the effects of mechanical polishing and chemical polishing on the surface roughness (Ra) and contact angle (wettability) of heat-cured, auto-cured and CAD/CAM denture base acrylic resins. Methods This study was conducted at the Advanced Dental Research Laboratory Center of King Abdulaziz University from March to June 2017. Three denture base materials were selected: heat cure poly-methylmethacrylate resin, thermoplastic (polyamide resin) and (CAD\\CAM) denture base resin. Sixty specimens were prepared and divided into three groups, twenty in each. Each group was divided according to the polishing techniques into (Mech P) and (Chem P), ten specimens in each; surface roughness and wettability were investigated. Data were analyzed by SPSS version 22, using one-way ANOVA and Pearson coefficient. Results One-way analysis of variance (ANOVA) and post hoc tests were used for comparing the surface roughness values between three groups which revealed a statistical significant difference between them (p1<0.001). Heat-cured denture base material of (Group I) in both methods, showed the highest mean surface roughness value (2.44±0.07, 2.72±0.09, Mech P and Chem P respectively); while CAD\\CAM denture base material (group III) showed the least mean values (1.08±0.23, 1.39±0.31, Mech P and Chem P respectively). CAD/CAM showed the least contact angle in both polishing methods, which were statistically significant at 5% level (p=0.034 and p<0.001). Conclusion Mechanical polishing produced lower surface roughness of CAD\\CAM denture base resin with superior smooth surface compared to chemical polishing. Mechanical polishing is considered the best effective polishing technique. CAD/CAM denture base material should be considered as the material of choice for complete denture construction in the near future, especially for older dental patients with changed salivary functions, because of its wettability. PMID:29238483

The influence of polishing techniques on pre-polymerized CAD\\CAM acrylic resin denture bases.

PubMed

Alammari, Manal Rahma

2017-10-01

Lately, computer-aided design and computer-aided manufacturing (CAD/CAM) has broadly been successfully employed in dentistry. The CAD/CAM systems have recently become commercially available for fabrication of complete dentures, and are considered as an alternative technique to conventionally processed acrylic resin bases. However, they have not yet been fully investigated. The purpose of this study was to inspect the effects of mechanical polishing and chemical polishing on the surface roughness (Ra) and contact angle (wettability) of heat-cured, auto-cured and CAD/CAM denture base acrylic resins. This study was conducted at the Advanced Dental Research Laboratory Center of King Abdulaziz University from March to June 2017. Three denture base materials were selected: heat cure poly-methylmethacrylate resin, thermoplastic (polyamide resin) and (CAD\\CAM) denture base resin. Sixty specimens were prepared and divided into three groups, twenty in each. Each group was divided according to the polishing techniques into (Mech P) and (Chem P), ten specimens in each; surface roughness and wettability were investigated. Data were analyzed by SPSS version 22, using one-way ANOVA and Pearson coefficient. One-way analysis of variance (ANOVA) and post hoc tests were used for comparing the surface roughness values between three groups which revealed a statistical significant difference between them (p 1 <0.001). Heat-cured denture base material of (Group I) in both methods, showed the highest mean surface roughness value (2.44±0.07, 2.72±0.09, Mech P and Chem P respectively); while CAD\\CAM denture base material (group III) showed the least mean values (1.08±0.23, 1.39±0.31, Mech P and Chem P respectively). CAD/CAM showed the least contact angle in both polishing methods, which were statistically significant at 5% level (p=0.034 and p<0.001). Mechanical polishing produced lower surface roughness of CAD\\CAM denture base resin with superior smooth surface compared to chemical polishing. Mechanical polishing is considered the best effective polishing technique. CAD/CAM denture base material should be considered as the material of choice for complete denture construction in the near future, especially for older dental patients with changed salivary functions, because of its wettability.

Analog Computer-Aided Detection (CAD) information can be more effective than binary marks.

PubMed

Cunningham, Corbin A; Drew, Trafton; Wolfe, Jeremy M

2017-02-01

In socially important visual search tasks, such as baggage screening and diagnostic radiology, experts miss more targets than is desirable. Computer-aided detection (CAD) programs have been developed specifically to improve performance in these professional search tasks. For example, in breast cancer screening, many CAD systems are capable of detecting approximately 90% of breast cancer, with approximately 0.5 false-positive detections per image. Nevertheless, benefits of CAD in clinical settings tend to be small (Birdwell, 2009) or even absent (Meziane et al., 2011; Philpotts, 2009). The marks made by a CAD system can be "binary," giving the same signal to any location where the signal is above some threshold. Alternatively, a CAD system presents an analog signal that reflects strength of the signal at a location. In the experiments reported, we compare analog and binary CAD presentations using nonexpert observers and artificial stimuli defined by two noisy signals: a visible color signal and an "invisible" signal that informed our simulated CAD system. We found that analog CAD generally yielded better overall performance than binary CAD. The analog benefit is similar at high and low target prevalence. Our data suggest that the form of the CAD signal can directly influence performance. Analog CAD may allow the computer to be more helpful to the searcher.

Two-view information fusion for improvement of computer-aided detection (CAD) of breast masses on mammograms

NASA Astrophysics Data System (ADS)

Wei, Jun; Sahiner, Berkman; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Helvie, Mark A.; Roubidoux, Marilyn A.; Zhou, Chuan; Ge, Jun; Zhang, Yiheng

2006-03-01

We are developing a two-view information fusion method to improve the performance of our CAD system for mass detection. Mass candidates on each mammogram were first detected with our single-view CAD system. Potential object pairs on the two-view mammograms were then identified by using the distance between the object and the nipple. Morphological features, Hessian feature, correlation coefficients between the two paired objects and texture features were used as input to train a similarity classifier that estimated a similarity scores for each pair. Finally, a linear discriminant analysis (LDA) classifier was used to fuse the score from the single-view CAD system and the similarity score. A data set of 475 patients containing 972 mammograms with 475 biopsy-proven masses was used to train and test the CAD system. All cases contained the CC view and the MLO or LM view. We randomly divided the data set into two independent sets of 243 cases and 232 cases. The training and testing were performed using the 2-fold cross validation method. The detection performance of the CAD system was assessed by free response receiver operating characteristic (FROC) analysis. The average test FROC curve was obtained from averaging the FP rates at the same sensitivity along the two corresponding test FROC curves from the 2-fold cross validation. At the case-based sensitivities of 90%, 85% and 80% on the test set, the single-view CAD system achieved an FP rate of 2.0, 1.5, and 1.2 FPs/image, respectively. With the two-view fusion system, the FP rates were reduced to 1.7, 1.3, and 1.0 FPs/image, respectively, at the corresponding sensitivities. The improvement was found to be statistically significant (p<0.05) by the AFROC method. Our results indicate that the two-view fusion scheme can improve the performance of mass detection on mammograms.

JAMSTEC Compact Arctic Drifter (J-CAD): A new Generation drifting buoy to observe the Arctic Ocean

NASA Astrophysics Data System (ADS)

Hatakeyama, Kiyoshi; Hosono, Masuo; Shimada, Koji; Kikuchi, Takashi; Nishino, Shigeto

The Arctic Ocean is one of the most sensitive regions to the earth environment changes. Japan Marine Science and Technology Center developed a new drift buoy to observe the Arctic Ocean. The name of the buoy is J-CAD (JAMSTEC Compact Arctic Drifter). From 1991 to 1993, JAMSTEC developed Ice-Ocean Environmental Buoy (IOEB) as a buoy to observe the Arctic Ocean in cooperation with Woods Hole Oceanographic Institution. The J-CAD is the buoy, which adopted the latest technology based on the knowledge and experience of IOEB development. The J-CAD was designed and developed by JAMSTEC and made by a Canadian Company MetOcean. JAMSTEC did design and development, and a Canadian company Met-Ocean made the J-CAD. It acquires meteorological and oceanographic data of the Arctic Ocean, and transmits the data that it measured via satellite. It dose also store the data inside its memory. An Inductive Modem system, which was developed by Sea-Bird Electronics, Inc. in the United States, was adopted in the underwater transmission system that data on each ocean sensor were collected. An ORBCOMM communication system was adopted for the satellite data transmission. J-CAD-1 was installed at 89°41'N 130°20'W on April 24, 2000, and the observation was started. August 1st was the day when 100 days have passed since the J-CAD-1 was installed on the North Pole. And now, the distance J-CAD-1 has covered exceeds 400 km, and it has transmitted data more than 500 k byte. A part of the data is introduced to the public in the homepage (http://w3.jamstec.go.jp: 8338) of the Arctic research group of JAMSTEC.

CAD-RADS™: Coronary Artery Disease - Reporting and Data System: An Expert Consensus Document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Radiology (ACR) and the North American Society for Cardiovascular Imaging (NASCI). Endorsed by the American College of Cardiology.

PubMed

Cury, Ricardo C; Abbara, Suhny; Achenbach, Stephan; Agatston, Arthur; Berman, Daniel S; Budoff, Matthew J; Dill, Karin E; Jacobs, Jill E; Maroules, Christopher D; Rubin, Geoffrey D; Rybicki, Frank J; Schoepf, U Joseph; Shaw, Leslee J; Stillman, Arthur E; White, Charles S; Woodard, Pamela K; Leipsic, Jonathon A

2016-12-01

The intent of CAD-RADS - Coronary Artery Disease Reporting and Data System is to create a standardized method to communicate findings of coronary CT angiography (coronary CTA) in order to facilitate decision-making regarding further patient management. The suggested CAD-RADS classification is applied on a per-patient basis and represents the highest-grade coronary artery lesion documented by coronary CTA. It ranges from CAD-RADS 0 (Zero) for the complete absence of stenosis and plaque to CAD-RADS 5 for the presence of at least one totally occluded coronary artery and should always be interpreted in conjunction with the impression found in the report. Specific recommendations are provided for further management of patients with stable or acute chest pain based on the CAD-RADS classification. The main goal of CAD-RADS is to standardize reporting of coronary CTA results and to facilitate communication of test results to referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will provide a framework of standardization that may benefit education, research, peer-review and quality assurance with the potential to ultimately result in improved quality of care. Copyright © 2016 Society of Cardiovascular Computed Tomography and the American College of Radiology. Published by Elsevier Inc. All rights reserved.

Computer-Aided Drafting. Education for Technology Employment.

ERIC Educational Resources Information Center

Northern Illinois Univ., De Kalb. Dept. of Technology.

This computer-aided drafting (CAD) curriculum was developed to provide drafting instructors in Illinois with a useful guide for relating an important new technological advance to the vocational classroom. The competency-based learning activity guides are written to be used with any CAD system being used at the secondary and postsecondary levels.…

Gaps Analysis of Integrating Product Design, Manufacturing, and Quality Data in The Supply Chain Using Model-Based Definition.

PubMed

Trainer, Asa; Hedberg, Thomas; Feeney, Allison Barnard; Fischer, Kevin; Rosche, Phil

2016-01-01

Advances in information technology triggered a digital revolution that holds promise of reduced costs, improved productivity, and higher quality. To ride this wave of innovation, manufacturing enterprises are changing how product definitions are communicated - from paper to models. To achieve industry's vision of the Model-Based Enterprise (MBE), the MBE strategy must include model-based data interoperability from design to manufacturing and quality in the supply chain. The Model-Based Definition (MBD) is created by the original equipment manufacturer (OEM) using Computer-Aided Design (CAD) tools. This information is then shared with the supplier so that they can manufacture and inspect the physical parts. Today, suppliers predominantly use Computer-Aided Manufacturing (CAM) and Coordinate Measuring Machine (CMM) models for these tasks. Traditionally, the OEM has provided design data to the supplier in the form of two-dimensional (2D) drawings, but may also include a three-dimensional (3D)-shape-geometry model, often in a standards-based format such as ISO 10303-203:2011 (STEP AP203). The supplier then creates the respective CAM and CMM models and machine programs to produce and inspect the parts. In the MBE vision for model-based data exchange, the CAD model must include product-and-manufacturing information (PMI) in addition to the shape geometry. Today's CAD tools can generate models with embedded PMI. And, with the emergence of STEP AP242, a standards-based model with embedded PMI can now be shared downstream. The on-going research detailed in this paper seeks to investigate three concepts. First, that the ability to utilize a STEP AP242 model with embedded PMI for CAD-to-CAM and CAD-to-CMM data exchange is possible and valuable to the overall goal of a more efficient process. Second, the research identifies gaps in tools, standards, and processes that inhibit industry's ability to cost-effectively achieve model-based-data interoperability in the pursuit of the MBE vision. Finally, it also seeks to explore the interaction between CAD and CMM processes and determine if the concept of feedback from CAM and CMM back to CAD is feasible. The main goal of our study is to test the hypothesis that model-based-data interoperability from CAD-to-CAM and CAD-to-CMM is feasible through standards-based integration. This paper presents several barriers to model-based-data interoperability. Overall, the project team demonstrated the exchange of product definition data between CAD, CAM, and CMM systems using standards-based methods. While gaps in standards coverage were identified, the gaps should not stop industry's progress toward MBE. The results of our study provide evidence in support of an open-standards method to model-based-data interoperability, which would provide maximum value and impact to industry.

Improving digital breast tomosynthesis reading time: A pilot multi-reader, multi-case study using concurrent Computer-Aided Detection (CAD).

PubMed

Balleyguier, Corinne; Arfi-Rouche, Julia; Levy, Laurent; Toubiana, Patrick R; Cohen-Scali, Franck; Toledano, Alicia Y; Boyer, Bruno

2017-12-01

Evaluate concurrent Computer-Aided Detection (CAD) with Digital Breast Tomosynthesis (DBT) to determine impact on radiologist performance and reading time. The CAD system detects and extracts suspicious masses, architectural distortions and asymmetries from DBT planes that are blended into corresponding synthetic images to form CAD-enhanced synthetic images. Review of CAD-enhanced images and navigation to corresponding planes to confirm or dismiss potential lesions allows radiologists to more quickly review DBT planes. A retrospective, crossover study with and without CAD was conducted with six radiologists who read an enriched sample of 80 DBT cases including 23 malignant lesions in 21 women. Area Under the Receiver Operating Characteristic (ROC) Curve (AUC) compared the readings with and without CAD to determine the effect of CAD on overall interpretation performance. Sensitivity, specificity, recall rate and reading time were also assessed. Multi-reader, multi-case (MRMC) methods accounting for correlation and requiring correct lesion localization were used to analyze all endpoints. AUCs were based on a 0-100% probability of malignancy (POM) score. Sensitivity and specificity were based on BI-RADS scores, where 3 or higher was positive. Average AUC across readers without CAD was 0.854 (range: 0.785-0.891, 95% confidence interval (CI): 0.769,0.939) and 0.850 (range: 0.746-0.905, 95% CI: 0.751,0.949) with CAD (95% CI for difference: -0.046,0.039), demonstrating non-inferiority of AUC. Average reduction in reading time with CAD was 23.5% (95% CI: 7.0-37.0% improvement), from an average 48.2 (95% CI: 39.1,59.6) seconds without CAD to 39.1 (95% CI: 26.2,54.5) seconds with CAD. Per-patient sensitivity was the same with and without CAD (0.865; 95% CI for difference: -0.070,0.070), and there was a small 0.022 improvement (95% CI for difference: -0.046,0.089) in per-lesion sensitivity from 0.790 without CAD to 0.812 with CAD. A slight reduction in specificity with a -0.014 difference (95% CI for difference: -0.079,0.050) and a small 0.025 increase (95% CI for difference: -0.036,0.087) in recall rate in non-cancer cases were observed with CAD. Concurrent CAD resulted in faster reading time with non-inferiority of radiologist interpretation performance. Radiologist sensitivity, specificity and recall rate were similar with and without CAD. Copyright © 2017 Elsevier B.V. All rights reserved.

A Geometry Based Infra-Structure for Computational Analysis and Design

NASA Technical Reports Server (NTRS)

Haimes, Robert

1998-01-01

The computational steps traditionally taken for most engineering analysis suites (computational fluid dynamics (CFD), structural analysis, heat transfer and etc.) are: (1) Surface Generation -- usually by employing a Computer Assisted Design (CAD) system; (2) Grid Generation -- preparing the volume for the simulation; (3) Flow Solver -- producing the results at the specified operational point; (4) Post-processing Visualization -- interactively attempting to understand the results. For structural analysis, integrated systems can be obtained from a number of commercial vendors. These vendors couple directly to a number of CAD systems and are executed from within the CAD Graphical User Interface (GUI). It should be noted that the structural analysis problem is more tractable than CFD; there are fewer mesh topologies used and the grids are not as fine (this problem space does not have the length scaling issues of fluids). For CFD, these steps have worked well in the past for simple steady-state simulations at the expense of much user interaction. The data was transmitted between phases via files. In most cases, the output from a CAD system could go to Initial Graphics Exchange Specification (IGES) or Standard Exchange Program (STEP) files. The output from Grid Generators and Solvers do not really have standards though there are a couple of file formats that can be used for a subset of the gridding (i.e. PLOT3D data formats). The user would have to patch up the data or translate from one format to another to move to the next step. Sometimes this could take days. Specifically the problems with this procedure are:(1) File based -- Information flows from one step to the next via data files with formats specified for that procedure. File standards, when they exist, are wholly inadequate. For example, geometry from CAD systems (transmitted via IGES files) is defined as disjoint surfaces and curves (as well as masses of other information of no interest for the Grid Generator). This is particularly onerous for modern CAD systems based on solid modeling. The part was a proper solid and in the translation to IGES has lost this important characteristic. STEP is another standard for CAD data that exists and supports the concept of a solid. The problem with STEP is that a solid modeling geometry kernel is required to query and manipulate the data within this type of file. (2) 'Good' Geometry. A bottleneck in getting results from a solver is the construction of proper geometry to be fed to the grid generator. With 'good' geometry a grid can be constructed in tens of minutes (even with a complex configuration) using unstructured techniques. Adroit multi-block methods are not far behind. This means that a million node steady-state solution can be computed on the order of hours (using current high performance computers) starting from this 'good' geometry. Unfortunately, the geometry usually transmitted from the CAD system is not 'good' in the grid generator sense. The grid generator needs smooth closed solid geometry. It can take a week (or more) of interaction with the CAD output (sometimes by hand) before the process can begin. One way Communication. (3) One-way Communication -- All information travels on from one phase to the next. This makes procedures like node adaptation difficult when attempting to add or move nodes that sit on bounding surfaces (when the actual surface data has been lost after the grid generation phase). Until this process can be automated, more complex problems such as multi-disciplinary analysis or using the above procedure for design becomes prohibitive. There is also no way to easily deal with this system in a modular manner. One can only replace the grid generator, for example, if the software reads and writes the same files. Instead of the serial approach to analysis as described above, CAPRI takes a geometry centric approach. This makes the actual geometry (not a discretized version) accessible to all phases of the analysis. The connection to the geometry is made through an Application Programming Interface (API) and NOT a file system. This API isolates the top-level applications (grid generators, solvers and visualization components) from the geometry engine. Also this allows the replacement of one geometry kernel with another, without effecting these top-level applications. For example, if UniGraphics is used as the CAD package then Parasolid (UG's own geometry engine) can be used for all geometric queries so that no solid geometry information is lost in a translation. This is much better than STEP because when the data is queried, the same software is executed as used in the CAD system. Therefore, one analyzes the exact part that is in the CAD system. CAPRI uses the same idea as the commercial structural analysis codes but does not specify control. Software components of the CAD system are used, but the analysis suite, not the CAD operator, specifies the control of the software session. This also means that the license issues (may be) minimized and individuals need not have to know how to operate a CAD system in order to run the suite.

The prediction of breast cancer biopsy outcomes using two CAD approaches that both emphasize an intelligible decision process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elter, M.; Schulz-Wendtland, R.; Wittenberg, T.

2007-11-15

Mammography is the most effective method for breast cancer screening available today. However, the low positive predictive value of breast biopsy resulting from mammogram interpretation leads to approximately 70% unnecessary biopsies with benign outcomes. To reduce the high number of unnecessary breast biopsies, several computer-aided diagnosis (CAD) systems have been proposed in the last several years. These systems help physicians in their decision to perform a breast biopsy on a suspicious lesion seen in a mammogram or to perform a short term follow-up examination instead. We present two novel CAD approaches that both emphasize an intelligible decision process to predictmore » breast biopsy outcomes from BI-RADS findings. An intelligible reasoning process is an important requirement for the acceptance of CAD systems by physicians. The first approach induces a global model based on decison-tree learning. The second approach is based on case-based reasoning and applies an entropic similarity measure. We have evaluated the performance of both CAD approaches on two large publicly available mammography reference databases using receiver operating characteristic (ROC) analysis, bootstrap sampling, and the ANOVA statistical significance test. Both approaches outperform the diagnosis decisions of the physicians. Hence, both systems have the potential to reduce the number of unnecessary breast biopsies in clinical practice. A comparison of the performance of the proposed decision tree and CBR approaches with a state of the art approach based on artificial neural networks (ANN) shows that the CBR approach performs slightly better than the ANN approach, which in turn results in slightly better performance than the decision-tree approach. The differences are statistically significant (p value <0.001). On 2100 masses extracted from the DDSM database, the CRB approach for example resulted in an area under the ROC curve of A(z)=0.89{+-}0.01, the decision-tree approach in A(z)=0.87{+-}0.01, and the ANN approach in A(z)=0.88{+-}0.01.« less

CAD/CAE Integration Enhanced by New CAD Services Standard

NASA Technical Reports Server (NTRS)

Claus, Russell W.

2002-01-01

A Government-industry team led by the NASA Glenn Research Center has developed a computer interface standard for accessing data from computer-aided design (CAD) systems. The Object Management Group, an international computer standards organization, has adopted this CAD services standard. The new standard allows software (e.g., computer-aided engineering (CAE) and computer-aided manufacturing software to access multiple CAD systems through one programming interface. The interface is built on top of a distributed computing system called the Common Object Request Broker Architecture (CORBA). CORBA allows the CAD services software to operate in a distributed, heterogeneous computing environment.

Analog Computer-Aided Detection (CAD) information can be more effective than binary marks

PubMed Central

Cunningham, Corbin A.; Drew, Trafton; Wolfe, Jeremy M.

2017-01-01

In socially important visual search tasks such as baggage screening and diagnostic radiology, experts miss more targets than is desirable. Computer Aided Detection (CAD) programs have been developed specifically to help improve performance in these professional search tasks. For example, in breast cancer screening, many CAD systems are capable of detecting approximately 90% of breast cancer, with approximately 0.5 false positive detections per image. Nevertheless, benefits of CAD in clinical settings tend to be small (Birdwell, 2009) or even absent (Meziane et al., 2011; Philpotts, 2009). The marks made by a CAD system can be “Binary”, giving the same signal to any location where the signal is above some threshold. Alternatively, a CAD system present an Analog signal that reflected strength of the signal at a location. In the experiments reported here, we compare analog and binary CAD presentations using non-expert observers and artificial stimuli defined by two noisy signals: a visible color signal and an "invisible" signal that informed our simulated CAD system. We found that analog CAD generally yielded better overall performance than binary CAD. The analog benefit is similar at high and low target prevalence. Our data suggest that the form of the CAD signal can directly influence performance. Analog CAD may allow the computer to be more helpful to the searcher. PMID:27928658

Adhesive Bonding to Computer-aided Design/ Computer-aided Manufacturing Esthetic Dental Materials: An Overview.

PubMed

Awad, Mohamed Moustafa; Alqahtani, H; Al-Mudahi, A; Murayshed, M S; Alrahlah, A; Bhandi, Shilpa H

2017-07-01

To review the adhesive bonding to different computer-aided design/computer-aided manufacturing (CAD/CAM) esthetic restorative materials. The use of CAD/CAM esthetic restorative materials has gained popularity in recent years. Several CAD/ CAM esthetic restorative materials are commercially available. Adhesive bonding is a major determinant of success of CAD/ CAM restorations. Review result: An account of the currently available bonding strategies are discussed with their rationale in various CAD/ CAM materials. Different surface treatment methods as well as adhesion promoters can be used to achieve reliable bonding of CAD/CAM restorative materials. Selection of bonding strategy to such material is determined based on its composition. Further evidence is required to evaluate the effect of new surface treatment methods, such as nonthermal atmospheric plasma and self-etching ceramic primer on bonding to different dental ceramics. An understanding of the currently available bonding strategies to CA/CAM materials can help the clinician to select the most indicated system for each category of materials.

Novel method for titanium crown casting using a combination of wax patterns fabricated by a CAD/CAM system and a non-expanded investment.

PubMed

Zhang, Zutai; Tamaki, Yukimichi; Hotta, Yasuhiro; Miyazaki, Takashi

2006-07-01

For titanium casting, most commercial investments for titanium recommend casting at a low mold temperature to reduce oxidation. However, the thermal expansion values of the molds at low casting temperatures may be insufficient. The purpose of the current study was to investigate the possibility of obtaining accurate titanium crown casts using wax pattern fabricated by a CAD/CAM system with a non-expanded mold. Three types of experimental magnesia-based investments (A, B and C) were made and their properties were evaluated for dental use. Two kinds of wax patterns for full-coverage coping crowns (S-0: cement space of 0 microm; S-20: cement space of 20 microm) were fabricated using a commercial CAD/CAM system. A traditional method (TM) using inlay wax was performed for comparison. The investment for titanium casting was decided from the fundamental data of experimental investments. Titanium crowns were replaced on the stone die and the thickness of the cement layer was evaluated. There were no significant differences for the setting time and setting expansion among the experimental investments, but the aluminous cement content played a role in hardening and contracting the mold. The fit of the titanium crowns differed significantly between the TM and the CAD/CAM system. The ranges of thickness obtained from the TM, S-0 and S-20 were 20.78-357.88 microm, 25.12-107.46 microm and 17.84-58.92 microm, respectively. High quality titanium crown casting was obtained using a combination of wax patterns fabricated by a CAD/CAM system and a non-expanded MgO-based investment.

Implementing an integrated engineering data base system: A developer's experience and the application to IPAD

NASA Technical Reports Server (NTRS)

Bruce, E. A.

1980-01-01

The software developed by the IPAD project, a new and very powerful tool for the implementation of integrated Computer Aided Design (CAD) systems in the aerospace engineering community, is discussed. The IPAD software is a tool and, as such, can be well applied or misapplied in any particular environment. The many benefits of an integrated CAD system are well documented, but there are few such systems in existence, especially in the mechanical engineering disciplines, and therefore little available experience to guide the implementor.

The Coronary Artery Disease-Reporting and Data System (CAD-RADS): Prognostic and Clinical Implications Associated With Standardized Coronary Computed Tomography Angiography Reporting.

PubMed

Xie, Joe X; Cury, Ricardo C; Leipsic, Jonathon; Crim, Matthew T; Berman, Daniel S; Gransar, Heidi; Budoff, Matthew J; Achenbach, Stephan; Ó Hartaigh, Bríain; Callister, Tracy Q; Marques, Hugo; Rubinshtein, Ronen; Al-Mallah, Mouaz H; Andreini, Daniele; Pontone, Gianluca; Cademartiri, Filippo; Maffei, Erica; Chinnaiyan, Kavitha; Raff, Gilbert; Hadamitzky, Martin; Hausleiter, Joerg; Feuchtner, Gudrun; Dunning, Allison; DeLago, Augustin; Kim, Yong-Jin; Kaufmann, Philipp A; Villines, Todd C; Chow, Benjamin J W; Hindoyan, Niree; Gomez, Millie; Lin, Fay Y; Jones, Erica; Min, James K; Shaw, Leslee J

2018-01-01

This study sought to assess clinical outcomes associated with the novel Coronary Artery Disease-Reporting and Data System (CAD-RADS) scores used to standardize coronary computed tomography angiography (CTA) reporting and their potential utility in guiding post-coronary CTA care. Clinical decision support is a major focus of health care policies aimed at improving guideline-directed care. Recently, CAD-RADS was developed to standardize coronary CTA reporting and includes clinical recommendations to facilitate patient management after coronary CTA. In the multinational CONFIRM (COronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter) registry, 5,039 patients without known coronary artery disease (CAD) underwent coronary CTA and were stratified by CAD-RADS scores, which rank CAD stenosis severity as 0 (0%), 1 (1% to 24%), 2 (25% to 49%), 3 (50% to 69%), 4A (70% to 99% in 1 to 2 vessels), 4B (70% to 99% in 3 vessels or ≥50% left main), or 5 (100%). Kaplan-Meier and multivariable Cox models were used to estimate all-cause mortality or myocardial infarction (MI). Receiver-operating characteristic (ROC) curves were used to compare CAD-RADS to the Duke CAD Index and traditional CAD classification. Referrals to invasive coronary angiography (ICA) after coronary CTA were also assessed. Cumulative 5-year event-free survival ranged from 95.2% to 69.3% for CAD-RADS 0 to 5 (p < 0.0001). Higher scores were associated with elevations in event risk (hazard ratio: 2.46 to 6.09; p < 0.0001). The ROC curve for prediction of death or MI was 0.7052 for CAD-RADS, which was noninferior to the Duke Index (0.7073; p = 0.893) and traditional CAD classification (0.7095; p = 0.783). ICA rates were 13% for CAD-RADS 0 to 2, 66% for CAD-RADS 3, and 84% for CAD-RADS ≥4A. For CAD-RADS 3, 58% of all catheterizations occurred within the first 30 days of follow-up. In a patient subset with available medication data, 57% of CAD-RADS 3 patients who received 30-day ICA were either asymptomatic or not receiving antianginal therapy at baseline, whereas only 32% had angina and were receiving medical therapy. CAD-RADS effectively identified patients at risk for adverse events. Frequent ICA use was observed among patients without severe CAD, many of whom were asymptomatic or not taking antianginal drugs. Incorporating CAD-RADS into coronary CTA reports may provide a novel opportunity to promote evidence-based care post-coronary CTA. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

A combined system for 3D printing cybersecurity

NASA Astrophysics Data System (ADS)

Straub, Jeremy

2017-06-01

Previous work has discussed the impact of cybersecurity breaches on 3D printed objects. Multiple attack types that could weaken objects, make them unsuitable for certain applications and even create safety hazards have been presented. This paper considers a visible light sensing-based verification system's efficacy as a means of thwarting cybersecurity threats to 3D printing. This system detects discrepancies between expected and actual printed objects (based on an independent pristine CAD model). Whether reliance on an independent CAD model is appropriate is also considered. The future of 3D printing is projected and the importance of cybersecurity in this future is discussed.

Management of CAD/CAM information: Key to improved manufacturing productivity

NASA Technical Reports Server (NTRS)

Fulton, R. E.; Brainin, J.

1984-01-01

A key element to improved industry productivity is effective management of CAD/CAM information. To stimulate advancements in this area, a joint NASA/Navy/Industry project designated Integrated Programs for Aerospace-Vehicle Design (IPAD) is underway with the goal of raising aerospace industry productivity through advancement of technology to integrate and manage information involved in the design and manufacturing process. The project complements traditional NASA/DOD research to develop aerospace design technology and the Air Force's Integrated Computer-Aided Manufacturing (ICAM) program to advance CAM technology. IPAD research is guided by an Industry Technical Advisory Board (ITAB) composed of over 100 repesentatives from aerospace and computer companies. The IPAD accomplishments to date in development of requirements and prototype software for various levels of company-wide CAD/CAM data management are summarized and plans for development of technology for management of distributed CAD/CAM data and information required to control future knowledge-based CAD/CAM systems are discussed.

Investigation of IGES for CAD/CAE data transfer

NASA Technical Reports Server (NTRS)

Zobrist, George W.

1989-01-01

In a CAD/CAE facility there is always the possibility that one may want to transfer the design graphics database from the native system to a non-native system. This may occur because of dissimilar systems within an organization or a new CAD/CAE system is to be purchased. The Initial Graphics Exchange Specification (IGES) was developed in an attempt to solve this scenario. IGES is a neutral database format into which the CAD/CAE native database format can be translated to and from. Translating the native design database format to IGES requires a pre-processor and transling from IGES to the native database format requires a post-processor. IGES is an artifice to represent CAD/CAE product data in a neutral environment to allow interfacing applications, archive the database, interchange of product data between dissimilar CAD/CAE systems, and other applications. The intent here is to present test data on translating design product data from a CAD/CAE system to itself and to translate data initially prepared in IGES format to various native design formats. This information can be utilized in planning potential procurement and developing a design discipline within the CAD/CAE community.

A CAD System for Hemorrhagic Stroke.

PubMed

Nowinski, Wieslaw L; Qian, Guoyu; Hanley, Daniel F

2014-09-01

Computer-aided detection/diagnosis (CAD) is a key component of routine clinical practice, increasingly used for detection, interpretation, quantification and decision support. Despite a critical need, there is no clinically accepted CAD system for stroke yet. Here we introduce a CAD system for hemorrhagic stroke. This CAD system segments, quantifies, and displays hematoma in 2D/3D, and supports evacuation of hemorrhage by thrombolytic treatment monitoring progression and quantifying clot removal. It supports seven-step workflow: select patient, add a new study, process patient's scans, show segmentation results, plot hematoma volumes, show 3D synchronized time series hematomas, and generate report. The system architecture contains four components: library, tools, application with user interface, and hematoma segmentation algorithm. The tools include a contour editor, 3D surface modeler, 3D volume measure, histogramming, hematoma volume plot, and 3D synchronized time-series hematoma display. The CAD system has been designed and implemented in C++. It has also been employed in the CLEAR and MISTIE phase-III, multicenter clinical trials. This stroke CAD system is potentially useful in research and clinical applications, particularly for clinical trials.

Quantitative assessment of multiple sclerosis lesion load using CAD and expert input

NASA Astrophysics Data System (ADS)

Gertych, Arkadiusz; Wong, Alexis; Sangnil, Alan; Liu, Brent J.

2008-03-01

Multiple sclerosis (MS) is a frequently encountered neurological disease with a progressive but variable course affecting the central nervous system. Outline-based lesion quantification in the assessment of lesion load (LL) performed on magnetic resonance (MR) images is clinically useful and provides information about the development and change reflecting overall disease burden. Methods of LL assessment that rely on human input are tedious, have higher intra- and inter-observer variability and are more time-consuming than computerized automatic (CAD) techniques. At present it seems that methods based on human lesion identification preceded by non-interactive outlining by CAD are the best LL quantification strategies. We have developed a CAD that automatically quantifies MS lesions, displays 3-D lesion map and appends radiological findings to original images according to current DICOM standard. CAD is also capable to display and track changes and make comparison between patient's separate MRI studies to determine disease progression. The findings are exported to a separate imaging tool for review and final approval by expert. Capturing and standardized archiving of manual contours is also implemented. Similarity coefficients calculated from quantities of LL in collected exams show a good correlation of CAD-derived results vs. those incorporated as expert's reading. Combining the CAD approach with an expert interaction may impact to the diagnostic work-up of MS patients because of improved reproducibility in LL assessment and reduced time for single MR or comparative exams reading. Inclusion of CAD-generated outlines as DICOM-compliant overlays into the image data can serve as a better reference in MS progression tracking.

Computer-aided design development transition for IPAD environment

NASA Technical Reports Server (NTRS)

Owens, H. G.; Mock, W. D.; Mitchell, J. C.

1980-01-01

The relationship of federally sponsored computer-aided design/computer-aided manufacturing (CAD/CAM) programs to the aircraft life cycle design process, an overview of NAAD'S CAD development program, an evaluation of the CAD design process, a discussion of the current computing environment within which NAAD is developing its CAD system, some of the advantages/disadvantages of the NAAD-IPAD approach, and CAD developments during transition into the IPAD system are discussed.

Computer Aided Drafting. Instructor's Guide.

ERIC Educational Resources Information Center

Henry, Michael A.

This guide is intended for use in introducing students to the operation and applications of computer-aided drafting (CAD) systems. The following topics are covered in the individual lessons: understanding CAD (CAD versus traditional manual drafting and care of software and hardware); using the components of a CAD system (primary and other input…

Computer-Aided Diagnosis in Medical Imaging: Historical Review, Current Status and Future Potential

PubMed Central

Doi, Kunio

2007-01-01

Computer-aided diagnosis (CAD) has become one of the major research subjects in medical imaging and diagnostic radiology. In this article, the motivation and philosophy for early development of CAD schemes are presented together with the current status and future potential of CAD in a PACS environment. With CAD, radiologists use the computer output as a “second opinion” and make the final decisions. CAD is a concept established by taking into account equally the roles of physicians and computers, whereas automated computer diagnosis is a concept based on computer algorithms only. With CAD, the performance by computers does not have to be comparable to or better than that by physicians, but needs to be complementary to that by physicians. In fact, a large number of CAD systems have been employed for assisting physicians in the early detection of breast cancers on mammograms. A CAD scheme that makes use of lateral chest images has the potential to improve the overall performance in the detection of lung nodules when combined with another CAD scheme for PA chest images. Because vertebral fractures can be detected reliably by computer on lateral chest radiographs, radiologists’ accuracy in the detection of vertebral fractures would be improved by the use of CAD, and thus early diagnosis of osteoporosis would become possible. In MRA, a CAD system has been developed for assisting radiologists in the detection of intracranial aneurysms. On successive bone scan images, a CAD scheme for detection of interval changes has been developed by use of temporal subtraction images. In the future, many CAD schemes could be assembled as packages and implemented as a part of PACS. For example, the package for chest CAD may include the computerized detection of lung nodules, interstitial opacities, cardiomegaly, vertebral fractures, and interval changes in chest radiographs as well as the computerized classification of benign and malignant nodules and the differential diagnosis of interstitial lung diseases. In order to assist in the differential diagnosis, it would be possible to search for and retrieve images (or lesions) with known pathology, which would be very similar to a new unknown case, from PACS when a reliable and useful method has been developed for quantifying the similarity of a pair of images for visual comparison by radiologists. PMID:17349778

Computer-aided detection system for chest radiography: reducing report turnaround times of examinations with abnormalities.

PubMed

Kao, E-Fong; Liu, Gin-Chung; Lee, Lo-Yeh; Tsai, Huei-Yi; Jaw, Twei-Shiun

2015-06-01

The ability to give high priority to examinations with pathological findings could be very useful to radiologists with large work lists who wish to first evaluate the most critical studies. A computer-aided detection (CAD) system for identifying chest examinations with abnormalities has therefore been developed. To evaluate the effectiveness of a CAD system on report turnaround times of chest examinations with abnormalities. The CAD system was designed to automatically mark chest examinations with possible abnormalities in the work list of radiologists interpreting chest examinations. The system evaluation was performed in two phases: two radiologists interpreted the chest examinations without CAD in phase 1 and with CAD in phase 2. The time information recorded by the radiology information system was then used to calculate the turnaround times. All chest examinations were reviewed by two other radiologists and were divided into normal and abnormal groups. The turnaround times for the examinations with pathological findings with and without the CAD system assistance were compared. The sensitivity and specificity of the CAD for chest abnormalities were 0.790 and 0.697, respectively, and use of the CAD system decreased the turnaround time for chest examinations with abnormalities by 44%. The turnaround times required for radiologists to identify chest examinations with abnormalities could be reduced by using the CAD system. This system could be useful for radiologists with large work lists who wish to first evaluate the most critical studies. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Gaps Analysis of Integrating Product Design, Manufacturing, and Quality Data in The Supply Chain Using Model-Based Definition

PubMed Central

Trainer, Asa; Hedberg, Thomas; Feeney, Allison Barnard; Fischer, Kevin; Rosche, Phil

2017-01-01

Advances in information technology triggered a digital revolution that holds promise of reduced costs, improved productivity, and higher quality. To ride this wave of innovation, manufacturing enterprises are changing how product definitions are communicated – from paper to models. To achieve industry's vision of the Model-Based Enterprise (MBE), the MBE strategy must include model-based data interoperability from design to manufacturing and quality in the supply chain. The Model-Based Definition (MBD) is created by the original equipment manufacturer (OEM) using Computer-Aided Design (CAD) tools. This information is then shared with the supplier so that they can manufacture and inspect the physical parts. Today, suppliers predominantly use Computer-Aided Manufacturing (CAM) and Coordinate Measuring Machine (CMM) models for these tasks. Traditionally, the OEM has provided design data to the supplier in the form of two-dimensional (2D) drawings, but may also include a three-dimensional (3D)-shape-geometry model, often in a standards-based format such as ISO 10303-203:2011 (STEP AP203). The supplier then creates the respective CAM and CMM models and machine programs to produce and inspect the parts. In the MBE vision for model-based data exchange, the CAD model must include product-and-manufacturing information (PMI) in addition to the shape geometry. Today's CAD tools can generate models with embedded PMI. And, with the emergence of STEP AP242, a standards-based model with embedded PMI can now be shared downstream. The on-going research detailed in this paper seeks to investigate three concepts. First, that the ability to utilize a STEP AP242 model with embedded PMI for CAD-to-CAM and CAD-to-CMM data exchange is possible and valuable to the overall goal of a more efficient process. Second, the research identifies gaps in tools, standards, and processes that inhibit industry's ability to cost-effectively achieve model-based-data interoperability in the pursuit of the MBE vision. Finally, it also seeks to explore the interaction between CAD and CMM processes and determine if the concept of feedback from CAM and CMM back to CAD is feasible. The main goal of our study is to test the hypothesis that model-based-data interoperability from CAD-to-CAM and CAD-to-CMM is feasible through standards-based integration. This paper presents several barriers to model-based-data interoperability. Overall, the project team demonstrated the exchange of product definition data between CAD, CAM, and CMM systems using standards-based methods. While gaps in standards coverage were identified, the gaps should not stop industry's progress toward MBE. The results of our study provide evidence in support of an open-standards method to model-based-data interoperability, which would provide maximum value and impact to industry. PMID:28691120

Role of Computer Aided Diagnosis (CAD) in the detection of pulmonary nodules on 64 row multi detector computed tomography.

PubMed

Prakashini, K; Babu, Satish; Rajgopal, K V; Kokila, K Raja

2016-01-01

To determine the overall performance of an existing CAD algorithm with thin-section computed tomography (CT) in the detection of pulmonary nodules and to evaluate detection sensitivity at a varying range of nodule density, size, and location. A cross-sectional prospective study was conducted on 20 patients with 322 suspected nodules who underwent diagnostic chest imaging using 64-row multi-detector CT. The examinations were evaluated on reconstructed images of 1.4 mm thickness and 0.7 mm interval. Detection of pulmonary nodules, initially by a radiologist of 2 years experience (RAD) and later by CAD lung nodule software was assessed. Then, CAD nodule candidates were accepted or rejected accordingly. Detected nodules were classified based on their size, density, and location. The performance of the RAD and CAD system was compared with the gold standard that is true nodules confirmed by consensus of senior RAD and CAD together. The overall sensitivity and false-positive (FP) rate of CAD software was calculated. Of the 322 suspected nodules, 221 were classified as true nodules on the consensus of senior RAD and CAD together. Of the true nodules, the RAD detected 206 (93.2%) and 202 (91.4%) by the CAD. CAD and RAD together picked up more number of nodules than either CAD or RAD alone. Overall sensitivity for nodule detection with the CAD program was 91.4%, and FP detection per patient was 5.5%. The CAD showed comparatively higher sensitivity for nodules of size 4-10 mm (93.4%) and nodules in hilar (100%) and central (96.5%) location when compared to RAD's performance. CAD performance was high in detecting pulmonary nodules including the small size and low-density nodules. CAD even with relatively high FP rate, assists and improves RAD's performance as a second reader, especially for nodules located in the central and hilar region and for small nodules by saving RADs time.

Is computer aided detection (CAD) cost effective in screening mammography? A model based on the CADET II study

PubMed Central

2011-01-01

Background Single reading with computer aided detection (CAD) is an alternative to double reading for detecting cancer in screening mammograms. The aim of this study is to investigate whether the use of a single reader with CAD is more cost-effective than double reading. Methods Based on data from the CADET II study, the cost-effectiveness of single reading with CAD versus double reading was measured in terms of cost per cancer detected. Cost (Pound (£), year 2007/08) of single reading with CAD versus double reading was estimated assuming a health and social service perspective and a 7 year time horizon. As the equipment cost varies according to the unit size a separate analysis was conducted for high, average and low volume screening units. One-way sensitivity analyses were performed by varying the reading time, equipment and assessment cost, recall rate and reader qualification. Results CAD is cost increasing for all sizes of screening unit. The introduction of CAD is cost-increasing compared to double reading because the cost of CAD equipment, staff training and the higher assessment cost associated with CAD are greater than the saving in reading costs. The introduction of single reading with CAD, in place of double reading, would produce an additional cost of £227 and £253 per 1,000 women screened in high and average volume units respectively. In low volume screening units, the high cost of purchasing the equipment will results in an additional cost of £590 per 1,000 women screened. One-way sensitivity analysis showed that the factors having the greatest effect on the cost-effectiveness of CAD with single reading compared with double reading were the reading time and the reader's professional qualification (radiologist versus advanced practitioner). Conclusions Without improvements in CAD effectiveness (e.g. a decrease in the recall rate) CAD is unlikely to be a cost effective alternative to double reading for mammography screening in UK. This study provides updated estimates of CAD costs in a full-field digital system and assessment cost for women who are re-called after initial screening. However, the model is highly sensitive to various parameters e.g. reading time, reader qualification, and equipment cost. PMID:21241473

Vagus-brain communication in atherosclerosis-related inflammation: a neuroimmunomodulation perspective of CAD.

PubMed

Gidron, Yori; Kupper, Nina; Kwaijtaal, Martijn; Winter, Jobst; Denollet, Johan

2007-12-01

The current understanding of the pathophysiology of atherosclerosis leading to coronary artery disease (CAD) emphasizes the role of inflammatory mediators. Given the bidirectional communication between the immune and central nervous systems, an important question is whether the brain can be "informed" about and modulate CAD-related inflammation. A candidate communicator and modulator is the vagus nerve. Until now, the vagus nerve has received attention in cardiology mainly due to its role in the parasympathetic cardiovascular response. However, the vagus nerve can also "inform" the brain about peripheral inflammation since its paraganglia have receptors for interleukin-1. Furthermore, its efferent branch has a local anti-inflammatory effect. These effects have not been considered in research on the vagus nerve in CAD or in vagus nerve stimulation trials in CAD. In addition, various behavioural interventions, including relaxation, may influence CAD prognosis by affecting vagal activity. Based on this converging evidence, we propose a neuroimmunomodulation approach to atherogenesis. In this model, the vagus nerve "informs" the brain about CAD-related cytokines; in turn, activation of the vagus (via vagus nerve stimulation, vagomimetic drugs or relaxation) induces an anti-inflammatory response that can slow down the chronic process of atherogenesis.

Software Tools for Shipbuilding Productivity

DTIC Science & Technology

1984-12-01

shipbuilding, is that design, manufacturing and robotic technology applications to shipbuilding have been proven. all aspects of shipbuilding is now a task...technical information about the process of Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) effectively has been a problem of serious and...Design (CAD) 3.4.1 CAD System Components 3.4.2 CAD System Benefits 3.4.3 New and Future CAD Technologies Computer Aided Manufacturing (CAM) 3.5.1 CAM

A method for using solid modeling CAD software to create an implant library for the fabrication of a custom abutment.

PubMed

Zhang, Jing; Zhang, Rimei; Ren, Guanghui; Zhang, Xiaojie

2017-02-01

This article describes a method that incorporates the solid modeling CAD software Solidworks with a dental milling machine to fabricate individual abutments in house. This process involves creating an implant library with 3-dimensional (3D) models and manufacturing a base, scan element, abutment, and crown anatomy. The 3D models can be imported into any dental computer-aided design and computer-aided (CAD-CAM) manufacturing system. This platform increases abutment design flexibility, as the base and scan elements can be designed to fit several shapes as needed to meet clinical requirements. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

21 CFR 872.3661 - Optical Impression Systems for CAD/CAM.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Optical Impression Systems for CAD/CAM. 872.3661... (CAD/CAM) is a device used to record the topographical characteristics of teeth, dental impressions, or... Design and Manufacturing (CAD/CAM) of Dental Restorations; Guidance for Industry and FDA.” For the...

21 CFR 872.3661 - Optical Impression Systems for CAD/CAM.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Optical Impression Systems for CAD/CAM. 872.3661... (CAD/CAM) is a device used to record the topographical characteristics of teeth, dental impressions, or... Design and Manufacturing (CAD/CAM) of Dental Restorations; Guidance for Industry and FDA.” For the...

21 CFR 872.3661 - Optical Impression Systems for CAD/CAM.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Optical Impression Systems for CAD/CAM. 872.3661... (CAD/CAM) is a device used to record the topographical characteristics of teeth, dental impressions, or... Design and Manufacturing (CAD/CAM) of Dental Restorations; Guidance for Industry and FDA.” For the...

Automated image-based colon cleansing for laxative-free CT colonography computer-aided polyp detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Linguraru, Marius George; Panjwani, Neil; Fletcher, Joel G.

2011-12-15

Purpose: To evaluate the performance of a computer-aided detection (CAD) system for detecting colonic polyps at noncathartic computed tomography colonography (CTC) in conjunction with an automated image-based colon cleansing algorithm. Methods: An automated colon cleansing algorithm was designed to detect and subtract tagged-stool, accounting for heterogeneity and poor tagging, to be used in conjunction with a colon CAD system. The method is locally adaptive and combines intensity, shape, and texture analysis with probabilistic optimization. CTC data from cathartic-free bowel preparation were acquired for testing and training the parameters. Patients underwent various colonic preparations with barium or Gastroview in divided dosesmore » over 48 h before scanning. No laxatives were administered and no dietary modifications were required. Cases were selected from a polyp-enriched cohort and included scans in which at least 90% of the solid stool was visually estimated to be tagged and each colonic segment was distended in either the prone or supine view. The CAD system was run comparatively with and without the stool subtraction algorithm. Results: The dataset comprised 38 CTC scans from prone and/or supine scans of 19 patients containing 44 polyps larger than 10 mm (22 unique polyps, if matched between prone and supine scans). The results are robust on fine details around folds, thin-stool linings on the colonic wall, near polyps and in large fluid/stool pools. The sensitivity of the CAD system is 70.5% per polyp at a rate of 5.75 false positives/scan without using the stool subtraction module. This detection improved significantly (p = 0.009) after automated colon cleansing on cathartic-free data to 86.4% true positive rate at 5.75 false positives/scan. Conclusions: An automated image-based colon cleansing algorithm designed to overcome the challenges of the noncathartic colon significantly improves the sensitivity of colon CAD by approximately 15%.« less

Turnkey CAD/CAM systems' integration with IPAD systems

NASA Technical Reports Server (NTRS)

Blauth, R. E.

1980-01-01

Today's commercially available turnkey CAD/CAM systems provide a highly interactive environment, and support many specialized application functions for the design/drafting/manufacturing process. This paper presents an overview of several aerospace companies which have successfully integrated turnkey CAD/CAM systems with their own company wide engineering and manufacturing systems. It also includes a vendor's view of the benefits as well as the disadvantages of such integration efforts. Specific emphasis is placed upon the selection of standards for representing geometric engineering data and for communicating such information between different CAD/CAM systems.

Cost-effectiveness of anatomical and functional test strategies for stable chest pain: public health perspective from a middle-income country.

PubMed

Bertoldi, Eduardo G; Stella, Steffen F; Rohde, Luis Eduardo P; Polanczyk, Carisi A

2017-05-04

The aim of this research is to evaluate the relative cost-effectiveness of functional and anatomical strategies for diagnosing stable coronary artery disease (CAD), using exercise (Ex)-ECG, stress echocardiogram (ECHO), single-photon emission CT (SPECT), coronary CT angiography (CTA) or stress cardiacmagnetic resonance (C-MRI). Decision-analytical model, comparing strategies of sequential tests for evaluating patients with possible stable angina in low, intermediate and high pretest probability of CAD, from the perspective of a developing nation's public healthcare system. Hypothetical cohort of patients with pretest probability of CAD between 20% and 70%. The primary outcome is cost per correct diagnosis of CAD. Proportion of false-positive or false-negative tests and number of unnecessary tests performed were also evaluated. Strategies using Ex-ECG as initial test were the least costly alternatives but generated more frequent false-positive initial tests and false-negative final diagnosis. Strategies based on CTA or ECHO as initial test were the most attractive and resulted in similar cost-effectiveness ratios (I$ 286 and I$ 305 per correct diagnosis, respectively). A strategy based on C-MRI was highly effective for diagnosing stable CAD, but its high cost resulted in unfavourable incremental cost-effectiveness (ICER) in moderate-risk and high-risk scenarios. Non-invasive strategies based on SPECT have been dominated. An anatomical diagnostic strategy based on CTA is a cost-effective option for CAD diagnosis. Functional strategies performed equally well when based on ECHO. C-MRI yielded acceptable ICER only at low pretest probability, and SPECT was not cost-effective in our analysis. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Correlation coefficient based supervised locally linear embedding for pulmonary nodule recognition.

PubMed

Wu, Panpan; Xia, Kewen; Yu, Hengyong

2016-11-01

Dimensionality reduction techniques are developed to suppress the negative effects of high dimensional feature space of lung CT images on classification performance in computer aided detection (CAD) systems for pulmonary nodule detection. An improved supervised locally linear embedding (SLLE) algorithm is proposed based on the concept of correlation coefficient. The Spearman's rank correlation coefficient is introduced to adjust the distance metric in the SLLE algorithm to ensure that more suitable neighborhood points could be identified, and thus to enhance the discriminating power of embedded data. The proposed Spearman's rank correlation coefficient based SLLE (SC(2)SLLE) is implemented and validated in our pilot CAD system using a clinical dataset collected from the publicly available lung image database consortium and image database resource initiative (LICD-IDRI). Particularly, a representative CAD system for solitary pulmonary nodule detection is designed and implemented. After a sequential medical image processing steps, 64 nodules and 140 non-nodules are extracted, and 34 representative features are calculated. The SC(2)SLLE, as well as SLLE and LLE algorithm, are applied to reduce the dimensionality. Several quantitative measurements are also used to evaluate and compare the performances. Using a 5-fold cross-validation methodology, the proposed algorithm achieves 87.65% accuracy, 79.23% sensitivity, 91.43% specificity, and 8.57% false positive rate, on average. Experimental results indicate that the proposed algorithm outperforms the original locally linear embedding and SLLE coupled with the support vector machine (SVM) classifier. Based on the preliminary results from a limited number of nodules in our dataset, this study demonstrates the great potential to improve the performance of a CAD system for nodule detection using the proposed SC(2)SLLE. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Computer-aided diagnosis of breast microcalcifications based on dual-tree complex wavelet transform.

PubMed

Jian, Wushuai; Sun, Xueyan; Luo, Shuqian

2012-12-19

Digital mammography is the most reliable imaging modality for breast carcinoma diagnosis and breast micro-calcifications is regarded as one of the most important signs on imaging diagnosis. In this paper, a computer-aided diagnosis (CAD) system is presented for breast micro-calcifications based on dual-tree complex wavelet transform (DT-CWT) to facilitate radiologists like double reading. Firstly, 25 abnormal ROIs were extracted according to the center and diameter of the lesions manually and 25 normal ROIs were selected randomly. Then micro-calcifications were segmented by combining space and frequency domain techniques. We extracted three texture features based on wavelet (Haar, DB4, DT-CWT) transform. Totally 14 descriptors were introduced to define the characteristics of the suspicious micro-calcifications. Principal Component Analysis (PCA) was used to transform these descriptors to a compact and efficient vector expression. Support Vector Machine (SVM) classifier was used to classify potential micro-calcifications. Finally, we used the receiver operating characteristic (ROC) curve and free-response operating characteristic (FROC) curve to evaluate the performance of the CAD system. The results of SVM classifications based on different wavelets shows DT-CWT has a better performance. Compared with other results, DT-CWT method achieved an accuracy of 96% and 100% for the classification of normal and abnormal ROIs, and the classification of benign and malignant micro-calcifications respectively. In FROC analysis, our CAD system for clinical dataset detection achieved a sensitivity of 83.5% at a false positive per image of 1.85. Compared with general wavelets, DT-CWT could describe the features more effectively, and our CAD system had a competitive performance.

Computer-aided diagnosis of breast microcalcifications based on dual-tree complex wavelet transform

PubMed Central

2012-01-01

Background Digital mammography is the most reliable imaging modality for breast carcinoma diagnosis and breast micro-calcifications is regarded as one of the most important signs on imaging diagnosis. In this paper, a computer-aided diagnosis (CAD) system is presented for breast micro-calcifications based on dual-tree complex wavelet transform (DT-CWT) to facilitate radiologists like double reading. Methods Firstly, 25 abnormal ROIs were extracted according to the center and diameter of the lesions manually and 25 normal ROIs were selected randomly. Then micro-calcifications were segmented by combining space and frequency domain techniques. We extracted three texture features based on wavelet (Haar, DB4, DT-CWT) transform. Totally 14 descriptors were introduced to define the characteristics of the suspicious micro-calcifications. Principal Component Analysis (PCA) was used to transform these descriptors to a compact and efficient vector expression. Support Vector Machine (SVM) classifier was used to classify potential micro-calcifications. Finally, we used the receiver operating characteristic (ROC) curve and free-response operating characteristic (FROC) curve to evaluate the performance of the CAD system. Results The results of SVM classifications based on different wavelets shows DT-CWT has a better performance. Compared with other results, DT-CWT method achieved an accuracy of 96% and 100% for the classification of normal and abnormal ROIs, and the classification of benign and malignant micro-calcifications respectively. In FROC analysis, our CAD system for clinical dataset detection achieved a sensitivity of 83.5% at a false positive per image of 1.85. Conclusions Compared with general wavelets, DT-CWT could describe the features more effectively, and our CAD system had a competitive performance. PMID:23253202

A Review of Developments in Computer-Based Systems to Image Teeth and Produce Dental Restorations

PubMed Central

Rekow, E. Dianne; Erdman, Arthur G.; Speidel, T. Michael

1987-01-01

Computer-aided design and manufacturing (CAD/CAM) make it possible to automate the creation of dental restorations. Currently practiced techniques are described. Three automated systems currently under development are described and compared. Advances in computer-aided design and computer-aided manufacturing (CAD/CAM) provide a new option for dentistry, creating an alternative technique for producing dental restorations. It is possible to create dental restorations that are automatically produced and meet or exceed current requirements for fit and occlusion.

A method for evaluating the performance of computer-aided detection of pulmonary nodules in lung cancer CT screening: detection limit for nodule size and density

PubMed Central

Kobayashi, Hajime; Ohkubo, Masaki; Narita, Akihiro; Marasinghe, Janaka C; Murao, Kohei; Matsumoto, Toru; Sone, Shusuke

2017-01-01

Objective: We propose the application of virtual nodules to evaluate the performance of computer-aided detection (CAD) of lung nodules in cancer screening using low-dose CT. Methods: The virtual nodules were generated based on the spatial resolution measured for a CT system used in an institution providing cancer screening and were fused into clinical lung images obtained at that institution, allowing site specificity. First, we validated virtual nodules as an alternative to artificial nodules inserted into a phantom. In addition, we compared the results of CAD analysis between the real nodules (n = 6) and the corresponding virtual nodules. Subsequently, virtual nodules of various sizes and contrasts between nodule density and background density (ΔCT) were inserted into clinical images (n = 10) and submitted for CAD analysis. Results: In the validation study, 46 of 48 virtual nodules had the same CAD results as artificial nodules (kappa coefficient = 0.913). Real nodules and the corresponding virtual nodules showed the same CAD results. The detection limits of the tested CAD system were determined in terms of size and density of peripheral lung nodules; we demonstrated that a nodule with a 5-mm diameter was detected when the nodule had a ΔCT > 220 HU. Conclusion: Virtual nodules are effective in evaluating CAD performance using site-specific scan/reconstruction conditions. Advances in knowledge: Virtual nodules can be an effective means of evaluating site-specific CAD performance. The methodology for guiding the detection limit for nodule size/density might be a useful evaluation strategy. PMID:27897029

Automatic detection of pulmonary nodules at spiral CT: first clinical experience with a computer-aided diagnosis system

NASA Astrophysics Data System (ADS)

Wormanns, Dag; Fiebich, Martin; Wietholt, Christian; Diederich, Stefan; Heindel, Walter

2000-06-01

We evaluated the practical application of a Computer-Aided Diagnosis (CAD) system for viewing spiral computed tomography (CT) of the chest low-dose screening examinations which includes an automatic detection of pulmonary nodules. A UNIX- based CAD system was developed including a detection algorithm for pulmonary nodules and a user interface providing an original axial image, the same image with nodules highlighted, a thin-slab MIP, and a cine mode. As yet, 26 CT examinations with 1625 images were reviewed in a clinical setting and reported by an experienced radiologist using both the CAD system and hardcopies. The CT studies exhibited 19 nodules found on the hardcopies in consensus reporting of 2 experienced radiologists. Viewing with the CAD system was more time consuming than using hardcopies (4.16 vs. 2.92 min) due to analyzing MIP and cine mode. The algorithm detected 49% (18/37) pulmonary nodules larger than 5 mm and 30% (21/70) of all nodules. It produced an average of 6.3 false positive findings per CT study. Most of the missed nodules were adjacent to the pleura. However, the program detected 6 nodules missed by the radiologists. Automatic nodule detection increases the radiologists's awareness of pulmonary lesions. Simultaneous display of axial image and thin-slab MIP makes the radiologist more confident in diagnosis of smaller pulmonary nodules. The CAD system improves the detection of pulmonary nodules at spiral CT. Lack of sensitivity and specificity is still an issue to be addressed but does not prevent practical use.

Automated computer-aided detection of prostate cancer in MR images: from a whole-organ to a zone-based approach

NASA Astrophysics Data System (ADS)

Litjens, G. J. S.; Barentsz, J. O.; Karssemeijer, N.; Huisman, H. J.

2012-03-01

MRI has shown to have great potential in prostate cancer localization and grading, but interpreting those exams requires expertise that is not widely available. Therefore, CAD applications are being developed to aid radiologists in detecting prostate cancer. Existing CAD applications focus on the prostate as a whole. However, in clinical practice transition zone cancer and peripheral zone cancer are considered to have different appearances. In this paper we present zone-specific CAD, in addition to an atlas based segmentation technique which includes zonal segmentation. Our CAD system consists of a detection and a classification stage. Prior to the detection stage the prostate is segmented into two zones. After segmentation features are extracted. Subsequently a likelihood map is generated on which local maxima detection is performed. For each local maximum a region is segmented. In the classification stage additional shape features are calculated, after which the regions are classified. Validation was performed on 288 data sets with MR-guided biopsy results as ground truth. Freeresponse Receiver Operating Characteristic (FROC) analysis was used for statistical evaluation. The difference between whole-prostate and zone-specific CAD was assessed using the difference between the FROCs. Our results show that evaluating the two zones separately results in an increase in performance compared to whole-prostate CAD. The FROC curves at .1, 1 and 3 false positives have a sensitivity of 0.0, 0.55 and 0.72 for whole-prostate and 0.08, 0.57 and 0.80 for zone-specific CAD. The FROC curve of the zone-specific CAD also showed significantly better performance overall (p < 0.05).

Flume Computer-Aided Design (CAD): Integrated CAD for Microflume Components and Systems

DTIC Science & Technology

2002-04-01

31 3.3: Matching the Mix Ratio (Part B...sizes) will be optimized based on the required flow rates and mixing ratios of the different species. The influence of etch depth is investigated on a...Inhibition Study In this network, the target protein is mixed with protease (i.e. enzyme that cleaves the target protein) and the protease inhibitor (the

CBT Pilot Program Instructional Guide. Basic Drafting Skills Curriculum Delivered through CAD Workstations and Artificial Intelligence Software.

ERIC Educational Resources Information Center

Smith, Richard J.; Sauer, Mardelle A.

This guide is intended to assist teachers in using computer-aided design (CAD) workstations and artificial intelligence software to teach basic drafting skills. The guide outlines a 7-unit shell program that may also be used as a generic authoring system capable of supporting computer-based training (CBT) in other subject areas. The first section…

Shape optimization and CAD

NASA Technical Reports Server (NTRS)

Rasmussen, John

1990-01-01

Structural optimization has attracted the attention since the days of Galileo. Olhoff and Taylor have produced an excellent overview of the classical research within this field. However, the interest in structural optimization has increased greatly during the last decade due to the advent of reliable general numerical analysis methods and the computer power necessary to use them efficiently. This has created the possibility of developing general numerical systems for shape optimization. Several authors, eg., Esping; Braibant & Fleury; Bennet & Botkin; Botkin, Yang, and Bennet; and Stanton have published practical and successful applications of general optimization systems. Ding and Homlein have produced extensive overviews of available systems. Furthermore, a number of commercial optimization systems based on well-established finite element codes have been introduced. Systems like ANSYS, IDEAS, OASIS, and NISAOPT are widely known examples. In parallel to this development, the technology of computer aided design (CAD) has gained a large influence on the design process of mechanical engineering. The CAD technology has already lived through a rapid development driven by the drastically growing capabilities of digital computers. However, the systems of today are still considered as being only the first generation of a long row of computer integrated manufacturing (CIM) systems. These systems to come will offer an integrated environment for design, analysis, and fabrication of products of almost any character. Thus, the CAD system could be regarded as simply a database for geometrical information equipped with a number of tools with the purpose of helping the user in the design process. Among these tools are facilities for structural analysis and optimization as well as present standard CAD features like drawing, modeling, and visualization tools. The state of the art of structural optimization is that a large amount of mathematical and mechanical techniques are available for the solution of single problems. By implementing collections of the available techniques into general software systems, operational environments for structural optimization have been created. The forthcoming years must bring solutions to the problem of integrating such systems into more general design environments. The result of this work should be CAD systems for rational design in which structural optimization is one important design tool among many others.

Lesion classification using clinical and visual data fusion by multiple kernel learning

NASA Astrophysics Data System (ADS)

Kisilev, Pavel; Hashoul, Sharbell; Walach, Eugene; Tzadok, Asaf

2014-03-01

To overcome operator dependency and to increase diagnosis accuracy in breast ultrasound (US), a lot of effort has been devoted to developing computer-aided diagnosis (CAD) systems for breast cancer detection and classification. Unfortunately, the efficacy of such CAD systems is limited since they rely on correct automatic lesions detection and localization, and on robustness of features computed based on the detected areas. In this paper we propose a new approach to boost the performance of a Machine Learning based CAD system, by combining visual and clinical data from patient files. We compute a set of visual features from breast ultrasound images, and construct the textual descriptor of patients by extracting relevant keywords from patients' clinical data files. We then use the Multiple Kernel Learning (MKL) framework to train SVM based classifier to discriminate between benign and malignant cases. We investigate different types of data fusion methods, namely, early, late, and intermediate (MKL-based) fusion. Our database consists of 408 patient cases, each containing US images, textual description of complaints and symptoms filled by physicians, and confirmed diagnoses. We show experimentally that the proposed MKL-based approach is superior to other classification methods. Even though the clinical data is very sparse and noisy, its MKL-based fusion with visual features yields significant improvement of the classification accuracy, as compared to the image features only based classifier.

Role of CadC and CadD in the 2,4-dichlorophenoxyacetic acid oxygenase system of Sphingomonas agrestis 58-1.

PubMed

Kijima, Kumiko; Mita, Hajime; Kawakami, Mitsuyasu; Amada, Kei

2018-02-02

In the present study, we confirm that 2,4-dichlorophenoxyacetic acid (2,4-D) oxygenase from Sphingomonas agrestis 58-1 belongs to the family of Rieske non-heme iron aromatic ring-hydroxylating oxygenases, which comprise a core enzyme (oxygenase), ferredoxin, and oxidoreductase. It has previously been shown that cadAB genes are necessary for the conversion of 2,4-D to 2,4-dichlorophenol; however, the respective roles of ferredoxin and oxidoreductase in the 2,4-D oxygenase system from S. agrestis 58-1 remain unknown. Using nucleotide sequence analysis of the plasmid pCADAB1 from Sphingomonas sp. ERG5, which degrades 4-chloro-2-methylphenoxyacetic acid and 2,4-D, Nielsen et al. identified orf95, upstream of cadA, and orf98, downstream of cadB, which were predicted and designated as cadD (oxidoreductase) and cadC (ferredoxin), respectively (Nielsen et al., PLoS One, 8, 1-9, 2013). These designations were the result of sequence analysis; therefore, we constructed an expression system of CadABC and CadABCD in Escherichia coli and assayed their enzyme activities. Our findings indicate that CadC is essential for the activity of 2,4-D oxygenase and CadD promotes CadABC activity in recombinant E. coli cells. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

A new CAD approach for improving efficacy of cancer screening

NASA Astrophysics Data System (ADS)

Zheng, Bin; Qian, Wei; Li, Lihua; Pu, Jiantao; Kang, Yan; Lure, Fleming; Tan, Maxine; Qiu, Yuchen

2015-03-01

Since performance and clinical utility of current computer-aided detection (CAD) schemes of detecting and classifying soft tissue lesions (e.g., breast masses and lung nodules) is not satisfactory, many researchers in CAD field call for new CAD research ideas and approaches. The purpose of presenting this opinion paper is to share our vision and stimulate more discussions of how to overcome or compensate the limitation of current lesion-detection based CAD schemes in the CAD research community. Since based on our observation that analyzing global image information plays an important role in radiologists' decision making, we hypothesized that using the targeted quantitative image features computed from global images could also provide highly discriminatory power, which are supplementary to the lesion-based information. To test our hypothesis, we recently performed a number of independent studies. Based on our published preliminary study results, we demonstrated that global mammographic image features and background parenchymal enhancement of breast MR images carried useful information to (1) predict near-term breast cancer risk based on negative screening mammograms, (2) distinguish between true- and false-positive recalls in mammography screening examinations, and (3) classify between malignant and benign breast MR examinations. The global case-based CAD scheme only warns a risk level of the cases without cueing a large number of false-positive lesions. It can also be applied to guide lesion-based CAD cueing to reduce false-positives but enhance clinically relevant true-positive cueing. However, before such a new CAD approach is clinically acceptable, more work is needed to optimize not only the scheme performance but also how to integrate with lesion-based CAD schemes in the clinical practice.

Evaluation of computer-aided detection of lesions in mammograms obtained with a digital phase-contrast mammography system.

PubMed

Tanaka, Toyohiko; Nitta, Norihisa; Ohta, Shinichi; Kobayashi, Tsuyoshi; Kano, Akiko; Tsuchiya, Keiko; Murakami, Yoko; Kitahara, Sawako; Wakamiya, Makoto; Furukawa, Akira; Takahashi, Masashi; Murata, Kiyoshi

2009-12-01

A computer-aided detection (CAD) system was evaluated for its ability to detect microcalcifications and masses on images obtained with a digital phase-contrast mammography (PCM) system, a system characterised by the sharp images provided by phase contrast and by the high resolution of 25-μm-pixel mammograms. Fifty abnormal and 50 normal mammograms were collected from about 3,500 mammograms and printed on film for reading on a light box. Seven qualified radiologists participated in an observer study based on receiver operating characteristic (ROC) analysis. The average of the areas under ROC curve (AUC) values for the ROC analysis with and without CAD were 0.927 and 0.897 respectively (P = 0.015). The AUC values improved from 0.840 to 0.888 for microcalcifications (P = 0.034) and from 0.947 to 0.962 for masses (P = 0.025) respectively. The application of CAD to the PCM system is a promising approach for the detection of breast cancer in its early stages.

Job expansion : an additional benefit of a computer aided dispatch/automatic vehicle locator (CAD/AVL) system

DOT National Transportation Integrated Search

2000-03-01

The Denver Regional Transportation District (RTD) acquired a CAD/AVL system that became fully operational in 1996. The CAD/AVL system added radio channels and covert alarms in buses, located vehicles in real time, and monitored schedule adherence. Th...

Comparison of Marginal and Internal Adaptation of CAD/CAM and Conventional Cement Retained Implant-Supported Single Crowns.

PubMed

Nejatidanesh, Farahnaz; Shakibamehr, Amir Hossein; Savabi, Omid

2016-02-01

To evaluate the accuracy of marginal and internal adaptation of 2 computer-aided design/computer-aided manufacturing (CAD/CAM) and 2 conventionally made cement retained implant-supported restorations. An abutment and its corresponding fixture analog (Astra Tech) were inserted in left central incisor area of a maxillary cast. Four types of implant-supported single restorations were fabricated on the abutment (n = 10): e.max CAD (Cerec AC system), zirconia-based (Cercon system), IPS e.max Press, and metal-ceramic restorations. The internal and marginal gaps of the studied groups were measured by replica method and stereomicroscope. Data were subjected to 1-way ANOVA and Scheffe post hoc tests (α = 0.05). Mean internal gaps of Cercon (59.48 ± 16.49 μm) and e.max Press (75.62 ± 26.92 μm) groups were significantly different from e.max CAD (120.29 ± 16.74 μm) group, but there was no significant difference between metal-ceramic restorations (89.65 ± 47.84 μm) and e.max CAD. The marginal gaps of e.max CAD (32.02 ± 10.38 μm) and Cercon restorations (34.26 ± 11.41 μm) were significantly superior from metal ceramics (59.19 ± 17.81 μm) and e.max press (74.99 ± 24.51 μm). Within the limitations of this study, it can be concluded that although the marginal and internal gaps of the studied implant-supported restorations were in the clinically acceptable range, single crowns made with CAD/CAM technology provide better marginal fit.

Evaluation of flexural strength and surface properties of prepolymerized CAD/CAM PMMA-based polymers used for digital 3D complete dentures.

PubMed

Arslan, Mustafa; Murat, Sema; Alp, Gulce; Zaimoglu, Ali

2018-01-01

The objectives of this in vitro study were to evaluate the flexural strength (FS), surface roughness (Ra), and hydrophobicity of polymethylmethacrylate (PMMA)-based computer-aided design/computer-aided manufacturing (CAD/CAM) polymers and to compare the properties of different CAD/CAM PMMA-based polymers with conventional heat-polymerized PMMA following thermal cycling. Twenty rectangular-shaped specimens (64 × 10 × 3.3 mm) were fabricated from three CAD/CAM PMMA-based polymers (M-PM Disc [M], AvaDent Puck Disc [A], and Pink CAD/CAM Disc Polident [P], and one conventional heat-polymerized PMMA (Promolux [C]), according to ISO 20795-1:2013 standards. The specimens were divided into two subgroups (n = 10), a control and a thermocycled group. The specimens in the thermocycled group were subjected to 5000 thermal cycling procedures (5 to 55°C; 30 s dwell times). The Ra value was measured using a profilometer. Contact angle (CA) was assessed using the sessile drop method to evaluate surface hydrophobicity. In addition, the FS of the specimens was tested in a universal testing machine at a crosshead speed of 1.0 mm/min. Surface texture of the materials was assessed using scanning electron microscope (SEM). The data were analyzed using two-way analysis of variance (ANOVA), followed by Tukey's HSD post-hoc test (α < 0.05). CAD/CAM PMMA-based polymers showed significantly higher FS than conventional heat-polymerized PMMA for each group (P < 0.001). CAD/CAM PMMA-based polymer [P] showed the highest FS, whereas conventional PMMA [C] showed the lowest FS before and after thermal cycling (P < 0.001). There were no significant differences among the Ra values of the tested denture base polymers in the control group (P > 0.05). In the thermocycled group, the lowest Ra value was observed for CAD/CAM PMMA-based polymer [M] (P < 0.001), whereas CAD/CAM PMMA-based polymers [A] and [P], and conventional PMMA [C] had similar Ra values (P > 0.05). Conventional PMMA [C] had a significantly lower CA and consequently lower hydrophobicity compared to the CAD/CAM polymers in the control group (P < 0.001). In the thermocycled group, CAD/CAM PMMA-based polymer [A] and conventional PMMA [C] had significantly higher CA, and consequently higher hydrophobicity when compared to CAD/CAM polymers [M] and [P] (P < 0.001). However, no significant differences were found among the other materials (P > 0.05). The FS and hydrophobicity of the CAD/CAM PMMA-based polymers were higher than the conventional heat-polymerized PMMA, whereas the CAD/CAM PMMA-based polymers had similar Ra values to the conventional PMMA. Thermocycling had a significant effect on FS and hydrophobicity except for the Ra of denture base materials.

Marginal adaptation and CAD-CAM technology: A systematic review of restorative material and fabrication techniques.

PubMed

Papadiochou, Sofia; Pissiotis, Argirios L

2018-04-01

The comparative assessment of computer-aided design and computer-aided manufacturing (CAD-CAM) technology and other fabrication techniques pertaining to marginal adaptation should be documented. Limited evidence exists on the effect of restorative material on the performance of a CAD-CAM system relative to marginal adaptation. The purpose of this systematic review was to investigate whether the marginal adaptation of CAD-CAM single crowns, fixed dental prostheses, and implant-retained fixed dental prostheses or their infrastructures differs from that obtained by other fabrication techniques using a similar restorative material and whether it depends on the type of restorative material. An electronic search of English-language literature published between January 1, 2000, and June 30, 2016, was conducted of the Medline/PubMed database. Of the 55 included comparative studies, 28 compared CAD-CAM technology with conventional fabrication techniques, 12 contrasted CAD-CAM technology and copy milling, 4 compared CAD-CAM milling with direct metal laser sintering (DMLS), and 22 investigated the performance of a CAD-CAM system regarding marginal adaptation in restorations/infrastructures produced with different restorative materials. Most of the CAD-CAM restorations/infrastructures were within the clinically acceptable marginal discrepancy (MD) range. The performance of a CAD-CAM system relative to marginal adaptation is influenced by the restorative material. Compared with CAD-CAM, most of the heat-pressed lithium disilicate crowns displayed equal or smaller MD values. Slip-casting crowns exhibited similar or better marginal accuracy than those fabricated with CAD-CAM. Cobalt-chromium and titanium implant infrastructures produced using a CAD-CAM system elicited smaller MD values than zirconia. The majority of cobalt-chromium restorations/infrastructures produced by DMLS displayed better marginal accuracy than those fabricated with the casting technique. Compared with copy milling, the majority of zirconia restorations/infrastructures produced by CAD-CAM milling exhibited better marginal adaptation. No clear conclusions can be drawn about the superiority of CAD-CAM milling over the casting technique and DMLS regarding marginal adaptation. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Non-localization and localization ROC analyses using clinically based scoring

NASA Astrophysics Data System (ADS)

Paquerault, Sophie; Samuelson, Frank W.; Myers, Kyle J.; Smith, Robert C.

2009-02-01

We are investigating the potential for differences in study conclusions when assessing the estimated impact of a computer-aided detection (CAD) system on readers' performance. The data utilized in this investigation were derived from a multi-reader multi-case observer study involving one hundred mammographic background images to which fixed-size and fixed-intensity Gaussian signals were added, generating a low- and high-intensity signal sets. The study setting allowed CAD assessment in two situations: when CAD sensitivity was 1) superior or 2) lower than the average reader. Seven readers were asked to review each set in the unaided and CAD-aided reading modes, mark and rate their findings. Using this data, we studied the effect on study conclusion of three clinically-based receiver operating characteristic (ROC) scoring definitions. These scoring definitions included both location-specific and non-location-specific rules. The results showed agreement in the estimated impact of CAD on the overall reader performance. In the study setting where CAD sensitivity is superior to the average reader, the mean difference in AUC between the CAD-aided read and unaided read was 0.049 (95%CIs: -0.027; 0.130) for the image scoring definition that is based on non-location-specific rules, and 0.104 (95%CIs: 0.036; 0.174) and 0.090 (95%CIs: 0.031; 0.155) for image scoring definitions that are based on location-specific rules. The increases in AUC were statistically significant for the location-specific scoring definitions. It was further observed that the variance on these estimates was reduced when using the location-specific scoring definitions compared to that using a non-location-specific scoring definition. In the study setting where CAD sensitivity is equivalent or lower than the average reader, the mean differences in AUC are slightly above 0.01 for all image scoring definitions. These increases in AUC were not statistical significant for any of the image scoring definitions. The results on the variance analysis differed from those observed in the other study setting. This investigation furthers our understanding of the relationships between non-localization-specific and localization-specific ROC assessment methodologies and their relevance to clinical practice.

CATO: a CAD tool for intelligent design of optical networks and interconnects

NASA Astrophysics Data System (ADS)

Chlamtac, Imrich; Ciesielski, Maciej; Fumagalli, Andrea F.; Ruszczyk, Chester; Wedzinga, Gosse

1997-10-01

Increasing communication speed requirements have created a great interest in very high speed optical and all-optical networks and interconnects. The design of these optical systems is a highly complex task, requiring the simultaneous optimization of various parts of the system, ranging from optical components' characteristics to access protocol techniques. Currently there are no computer aided design (CAD) tools on the market to support the interrelated design of all parts of optical communication systems, thus the designer has to rely on costly and time consuming testbed evaluations. The objective of the CATO (CAD tool for optical networks and interconnects) project is to develop a prototype of an intelligent CAD tool for the specification, design, simulation and optimization of optical communication networks. CATO allows the user to build an abstract, possible incomplete, model of the system, and determine its expected performance. Based on design constraints provided by the user, CATO will automatically complete an optimum design, using mathematical programming techniques, intelligent search methods and artificial intelligence (AI). Initial design and testing of a CATO prototype (CATO-1) has been completed recently. The objective was to prove the feasibility of combining AI techniques, simulation techniques, an optical device library and a graphical user interface into a flexible CAD tool for obtaining optimal communication network designs in terms of system cost and performance. CATO-1 is an experimental tool for designing packet-switching wavelength division multiplexing all-optical communication systems using a LAN/MAN ring topology as the underlying network. The two specific AI algorithms incorporated are simulated annealing and a genetic algorithm. CATO-1 finds the optimal number of transceivers for each network node, using an objective function that includes the cost of the devices and the overall system performance.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, K.L.

This document has been developed to provide guidance in the interchange of electronic CAD data with Martin Marietta Energy Systems, Inc., Oak Ridge, Tennessee. It is not meant to be as comprehensive as the existing standards and specifications, but to provide a minimum set of practices that will enhance the success of the CAD data exchange. It is now a Department of Energy (DOE) Oak Ridge Field Office requirement that Architect-Engineering (A-E) firms prepare all new drawings using a Computer Aided Design (CAD) system that is compatible with the Facility Manager`s (FM) CAD system. For Oak Ridge facilities, the CADmore » system used for facility design by the FM, Martin Marietta Energy Systems, Inc., is Intregraph. The format for interchange of CAD data for Oak Ridge facilities will be the Intergraph MicroStation/IGDS format.« less

Costs of management of patients with coronary artery disease in Poland: the multicenter RECENT study.

PubMed

Jaworski, Rafał; Jankowska, Ewa A; Ponikowski, Piotr; Banasiak, Waldemar

2012-01-01

Treatment of coronary artery disease (CAD) generates the major part of public health expenditure in the developed countries. The aim of the study was to estimate costs associated with the diagnosis and treatment of patients with CAD in Poland. Costs were estimated in a representative sample of 2593 patients with CAD receiving general practitioner (n = 1977) or specialist care (n = 616) in 2005 (the multicenter RECENT study). Data from the National Health Fund, Social Insurance Institution, Central Statistical Office, and current literature were used. The total annual cost of CAD reached €2254.17 per patient, with 48% accounting for direct medical costs (drugs, medical consultations, laboratory tests, diagnostic procedures, invasive treatment, hospitalizations, emergency care) and 52% for indirect costs (related to absence at work and disability). Eighty-one percent of total direct medical costs were covered by the public payer (including 30% of pharmacological treatment costs). Direct medical costs covered by the public payer were higher in men and in patients with more severe angina symptoms (both P <0.05). In the model based on the lowest prevalence of CAD (estimated based on the real population of patients treated in 2005), direct medical costs covered by the public payer reached €617.6 million, i.e., around 7% of the total public health expenditure in Poland in 2005. Modern management of CAD imposes enormous economic burden on the public health system in Poland. There is a need to develop and implement strategies that would optimize health care costs associated with the treatment of CAD.

Deep neural network-based computer-assisted detection of cerebral aneurysms in MR angiography.

PubMed

Nakao, Takahiro; Hanaoka, Shouhei; Nomura, Yukihiro; Sato, Issei; Nemoto, Mitsutaka; Miki, Soichiro; Maeda, Eriko; Yoshikawa, Takeharu; Hayashi, Naoto; Abe, Osamu

2018-04-01

The usefulness of computer-assisted detection (CAD) for detecting cerebral aneurysms has been reported; therefore, the improved performance of CAD will help to detect cerebral aneurysms. To develop a CAD system for intracranial aneurysms on unenhanced magnetic resonance angiography (MRA) images based on a deep convolutional neural network (CNN) and a maximum intensity projection (MIP) algorithm, and to demonstrate the usefulness of the system by training and evaluating it using a large dataset. Retrospective study. There were 450 cases with intracranial aneurysms. The diagnoses of brain aneurysms were made on the basis of MRA, which was performed as part of a brain screening program. Noncontrast-enhanced 3D time-of-flight (TOF) MRA on 3T MR scanners. In our CAD, we used a CNN classifier that predicts whether each voxel is inside or outside aneurysms by inputting MIP images generated from a volume of interest (VOI) around the voxel. The CNN was trained in advance using manually inputted labels. We evaluated our method using 450 cases with intracranial aneurysms, 300 of which were used for training, 50 for parameter tuning, and 100 for the final evaluation. Free-response receiver operating characteristic (FROC) analysis. Our CAD system detected 94.2% (98/104) of aneurysms with 2.9 false positives per case (FPs/case). At a sensitivity of 70%, the number of FPs/case was 0.26. We showed that the combination of a CNN and an MIP algorithm is useful for the detection of intracranial aneurysms. 4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:948-953. © 2017 International Society for Magnetic Resonance in Medicine.

Recent advances in laser triangulation-based measurement of airfoil surfaces

NASA Astrophysics Data System (ADS)

Hageniers, Omer L.

1995-01-01

The measurement of aircraft jet engine turbine and compressor blades requires a high degree of accuracy. This paper will address the development and performance attributes of a noncontact electro-optical gaging system specifically designed to meet the airfoil dimensional measurement requirements inherent in turbine and compressor blade manufacture and repair. The system described consists of the following key components: a high accuracy, dual channel, laser based optical sensor, a four degree of freedom mechanical manipulator system and a computer based operator interface. Measurement modes of the system include point by point data gathering at rates up to 3 points per second and an 'on-the-fly' mode where points can be gathered at data rates up to 20 points per second at surface scanning speeds of up to 1 inch per second. Overall system accuracy is +/- 0.0005 inches in a configuration that is useable in the blade manufacturing area. The systems ability to input design data from CAD data bases and output measurement data in a CAD compatible data format is discussed.

Role of Computer Aided Diagnosis (CAD) in the detection of pulmonary nodules on 64 row multi detector computed tomography

PubMed Central

Prakashini, K; Babu, Satish; Rajgopal, KV; Kokila, K Raja

2016-01-01

Aims and Objectives: To determine the overall performance of an existing CAD algorithm with thin-section computed tomography (CT) in the detection of pulmonary nodules and to evaluate detection sensitivity at a varying range of nodule density, size, and location. Materials and Methods: A cross-sectional prospective study was conducted on 20 patients with 322 suspected nodules who underwent diagnostic chest imaging using 64-row multi-detector CT. The examinations were evaluated on reconstructed images of 1.4 mm thickness and 0.7 mm interval. Detection of pulmonary nodules, initially by a radiologist of 2 years experience (RAD) and later by CAD lung nodule software was assessed. Then, CAD nodule candidates were accepted or rejected accordingly. Detected nodules were classified based on their size, density, and location. The performance of the RAD and CAD system was compared with the gold standard that is true nodules confirmed by consensus of senior RAD and CAD together. The overall sensitivity and false-positive (FP) rate of CAD software was calculated. Observations and Results: Of the 322 suspected nodules, 221 were classified as true nodules on the consensus of senior RAD and CAD together. Of the true nodules, the RAD detected 206 (93.2%) and 202 (91.4%) by the CAD. CAD and RAD together picked up more number of nodules than either CAD or RAD alone. Overall sensitivity for nodule detection with the CAD program was 91.4%, and FP detection per patient was 5.5%. The CAD showed comparatively higher sensitivity for nodules of size 4–10 mm (93.4%) and nodules in hilar (100%) and central (96.5%) location when compared to RAD's performance. Conclusion: CAD performance was high in detecting pulmonary nodules including the small size and low-density nodules. CAD even with relatively high FP rate, assists and improves RAD's performance as a second reader, especially for nodules located in the central and hilar region and for small nodules by saving RADs time. PMID:27578931

An application protocol for CAD to CAD transfer of electronic information

NASA Technical Reports Server (NTRS)

Azu, Charles C., Jr.

1993-01-01

The exchange of Computer Aided Design (CAD) information between dissimilar CAD systems is a problem. This is especially true for transferring electronics CAD information such as multi-chip module (MCM), hybrid microcircuit assembly (HMA), and printed circuit board (PCB) designs. Currently, there exists several neutral data formats for transferring electronics CAD information. These include IGES, EDIF, and DXF formats. All these formats have limitations for use in exchanging electronic data. In an attempt to overcome these limitations, the Navy's MicroCIM program implemented a project to transfer hybrid microcircuit design information between dissimilar CAD systems. The IGES (Initial Graphics Exchange Specification) format is used since it is well established within the CAD industry. The goal of the project is to have a complete transfer of microelectronic CAD information, using IGES, without any data loss. An Application Protocol (AP) is being developed to specify how hybrid microcircuit CAD information will be represented by IGES entity constructs. The AP defines which IGES data items are appropriate for describing HMA geometry, connectivity, and processing as well as HMA material characteristics.

Digital hand atlas for web-based bone age assessment: system design and implementation

NASA Astrophysics Data System (ADS)

Cao, Fei; Huang, H. K.; Pietka, Ewa; Gilsanz, Vicente

2000-04-01

A frequently used assessment method of skeletal age is atlas matching by a radiological examination of a hand image against a small set of Greulich-Pyle patterns of normal standards. The method however can lead to significant deviation in age assessment, due to a variety of observers with different levels of training. The Greulich-Pyle atlas based on middle upper class white populations in the 1950s, is also not fully applicable for children of today, especially regarding the standard development in other racial groups. In this paper, we present our system design and initial implementation of a digital hand atlas and computer-aided diagnostic (CAD) system for Web-based bone age assessment. The digital atlas will remove the disadvantages of the currently out-of-date one and allow the bone age assessment to be computerized and done conveniently via Web. The system consists of a hand atlas database, a CAD module and a Java-based Web user interface. The atlas database is based on a large set of clinically normal hand images of diverse ethnic groups. The Java-based Web user interface allows users to interact with the hand image database form browsers. Users can use a Web browser to push a clinical hand image to the CAD server for a bone age assessment. Quantitative features on the examined image, which reflect the skeletal maturity, is then extracted and compared with patterns from the atlas database to assess the bone age.

A Multidisciplinary Research Team Approach to Computer-Aided Drafting (CAD) System Selection. Final Report.

ERIC Educational Resources Information Center

Franken, Ken; And Others

A multidisciplinary research team was assembled to review existing computer-aided drafting (CAD) systems for the purpose of enabling staff in the Design Drafting Department at Linn Technical College (Missouri) to select the best system out of the many CAD systems in existence. During the initial stage of the evaluation project, researchers…

Bone age assessment by content-based image retrieval and case-based reasoning

NASA Astrophysics Data System (ADS)

Fischer, Benedikt; Welter, Petra; Grouls, Christoph; Günther, Rolf W.; Deserno, Thomas M.

2011-03-01

Skeletal maturity is assessed visually by comparing hand radiographs to a standardized reference image atlas. Most common are the methods by Greulich & Pyle and Tanner & Whitehouse. For computer-aided diagnosis (CAD), local image regions of interest (ROI) such as the epiphysis or the carpal areas are extracted and evaluated. Heuristic approaches trying to automatically extract, measure and classify bones and distances between bones suffer from the high variability of biological material and the differences in bone development resulting from age, gender and ethnic origin. Content-based image retrieval (CBIR) provides a robust solution without delineating and measuring bones. In this work, epiphyseal ROIs (eROIS) of a hand radiograph are compared to previous cases with known age, mimicking a human observer. Leaving-one-out experiments are conducted on 1,102 left hand radiographs and 15,428 metacarpal and phalangeal eROIs from the publicly available USC hand atlas. The similarity of the eROIs is assessed by a combination of cross-correlation, image distortion model, and Tamura texture features, yielding a mean error rate of 0.97 years and a variance of below 0.63 years. Furthermore, we introduce a publicly available online-demonstration system, where queries on the USC dataset as well as on uploaded radiographs are performed for instant CAD. In future, we plan to evaluate physician with CBIR-CAD against physician without CBIR-CAD rather than physician vs. CBIR-CAD.

Understanding dental CAD/CAM for restorations--accuracy from a mechanical engineering viewpoint.

PubMed

Tapie, Laurent; Lebon, Nicolas; Mawussi, Bernardin; Fron-Chabouis, Hélène; Duret, Francois; Attal, Jean-Pierre

2015-01-01

As is the case in the field of medicine, as well as in most areas of daily life, digital technology is increasingly being introduced into dental practice. Computer-aided design/ computer-aided manufacturing (CAD/CAM) solutions are available not only for chairside practice but also for creating inlays, crowns, fixed partial dentures (FPDs), implant abutments, and other dental prostheses. CAD/CAM dental practice can be considered as the handling of devices and software processing for the almost automatic design and creation of dental restorations. However, dentists who want to use dental CAD/CAM systems often do not have enough information to understand the variations offered by such technology practice. Knowledge of the random and systematic errors in accuracy with CAD/CAM systems can help to achieve successful restorations with this technology, and help with the purchasing of a CAD/CAM system that meets the clinical needs of restoration. This article provides a mechanical engineering viewpoint of the accuracy of CAD/ CAM systems, to help dentists understand the impact of this technology on restoration accuracy.

Tuner control system of Spoke012 SRF cavity for C-ADS injector I

NASA Astrophysics Data System (ADS)

Liu, Na; Sun, Yi; Wang, Guang-Wei; Mi, Zheng-Hui; Lin, Hai-Ying; Wang, Qun-Yao; Liu, Rong; Ma, Xin-Peng

2016-09-01

A new tuner control system for spoke superconducting radio frequency (SRF) cavities has been developed and applied to cryomodule I of the C-ADS injector I at the Institute of High Energy Physics, Chinese Academy of Sciences. We have successfully implemented the tuner controller based on Programmable Logic Controller (PLC) for the first time and achieved a cavity tuning phase error of ±0.7° (about ±4 Hz peak to peak) in the presence of electromechanical coupled resonance. This paper presents preliminary experimental results based on the PLC tuner controller under proton beam commissioning. Supported by Proton linac accelerator I of China Accelerator Driven sub-critical System (Y12C32W129)

Enhancements in medicine by integrating content based image retrieval in computer-aided diagnosis

NASA Astrophysics Data System (ADS)

Aggarwal, Preeti; Sardana, H. K.

2010-02-01

Computer-aided diagnosis (CAD) has become one of the major research subjects in medical imaging and diagnostic radiology. With cad, radiologists use the computer output as a "second opinion" and make the final decisions. Retrieving images is a useful tool to help radiologist to check medical image and diagnosis. The impact of contentbased access to medical images is frequently reported but existing systems are designed for only a particular context of diagnosis. The challenge in medical informatics is to develop tools for analyzing the content of medical images and to represent them in a way that can be efficiently searched and compared by the physicians. CAD is a concept established by taking into account equally the roles of physicians and computers. To build a successful computer aided diagnostic system, all the relevant technologies, especially retrieval need to be integrated in such a manner that should provide effective and efficient pre-diagnosed cases with proven pathology for the current case at the right time. In this paper, it is suggested that integration of content-based image retrieval (CBIR) in cad can bring enormous results in medicine especially in diagnosis. This approach is also compared with other approaches by highlighting its advantages over those approaches.

CAD system for footwear design based on whole real 3D data of last surface

NASA Astrophysics Data System (ADS)

Song, Wanzhong; Su, Xianyu

2000-10-01

Two major parts of application of CAD in footwear design are studied: the development of last surface; computer-aided design of planar shoe-template. A new quasi-experiential development algorithm of last surface based on triangulation approximation is presented. This development algorithm consumes less time and does not need any interactive operation for precisely development compared with other development algorithm of last surface. Based on this algorithm, a software, SHOEMAKERTM, which contains computer aided automatic measurement, automatic development of last surface and computer aide design of shoe-template has been developed.

Computer-aided diagnosis (CAD) for colonoscopy

NASA Astrophysics Data System (ADS)

Gu, Jia; Poirson, Allen

2007-03-01

Colorectal cancer is the second leading cause of cancer deaths, and ranks third for new cancer cases and cancer mortality for both men and women. However, its death rate can be dramatically reduced by appropriate treatment when early detection is available. The purpose of colonoscopy is to identify and assess the severity of lesions, which may be flat or protruding. Due to the subjective nature of the examination, colonoscopic proficiency is highly variable and dependent upon the colonoscopist's knowledge and experience. An automated image processing system providing an objective, rapid, and inexpensive analysis of video from a standard colonoscope could provide a valuable tool for screening and diagnosis. In this paper, we present the design, functionality and preliminary results of its Computer-Aided-Diagnosis (CAD) system for colonoscopy - ColonoCAD TM. ColonoCAD is a complex multi-sensor, multi-data and multi-algorithm image processing system, incorporating data management and visualization, video quality assessment and enhancement, calibration, multiple view based reconstruction, feature extraction and classification. As this is a new field in medical image processing, our hope is that this paper will provide the framework to encourage and facilitate collaboration and discussion between industry, academia, and medical practitioners.

Data engineering systems: Computerized modeling and data bank capabilities for engineering analysis

NASA Technical Reports Server (NTRS)

Kopp, H.; Trettau, R.; Zolotar, B.

1984-01-01

The Data Engineering System (DES) is a computer-based system that organizes technical data and provides automated mechanisms for storage, retrieval, and engineering analysis. The DES combines the benefits of a structured data base system with automated links to large-scale analysis codes. While the DES provides the user with many of the capabilities of a computer-aided design (CAD) system, the systems are actually quite different in several respects. A typical CAD system emphasizes interactive graphics capabilities and organizes data in a manner that optimizes these graphics. On the other hand, the DES is a computer-aided engineering system intended for the engineer who must operationally understand an existing or planned design or who desires to carry out additional technical analysis based on a particular design. The DES emphasizes data retrieval in a form that not only provides the engineer access to search and display the data but also links the data automatically with the computer analysis codes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bueno, G.; Ruiz, M.; Sanchez, S

Breast cancer continues to be an important health problem between women population. Early detection is the only way to improve breast cancer prognosis and significantly reduce women mortality. It is by using CAD systems that radiologist can improve their ability to detect, and classify lesions in mammograms. In this study the usefulness of using B-spline based on a gradient scheme and compared to wavelet and adaptative filtering has been investigated for calcification lesion detection and as part of CAD systems. The technique has been applied to different density tissues. A qualitative validation shows the success of the method.

Wavelet method for CT colonography computer-aided polyp detection.

PubMed

Li, Jiang; Van Uitert, Robert; Yao, Jianhua; Petrick, Nicholas; Franaszek, Marek; Huang, Adam; Summers, Ronald M

2008-08-01

Computed tomographic colonography (CTC) computer aided detection (CAD) is a new method to detect colon polyps. Colonic polyps are abnormal growths that may become cancerous. Detection and removal of colonic polyps, particularly larger ones, has been shown to reduce the incidence of colorectal cancer. While high sensitivities and low false positive rates are consistently achieved for the detection of polyps sized 1 cm or larger, lower sensitivities and higher false positive rates occur when the goal of CAD is to identify "medium"-sized polyps, 6-9 mm in diameter. Such medium-sized polyps may be important for clinical patient management. We have developed a wavelet-based postprocessor to reduce false positives for this polyp size range. We applied the wavelet-based postprocessor to CTC CAD findings from 44 patients in whom 45 polyps with sizes of 6-9 mm were found at segmentally unblinded optical colonoscopy and visible on retrospective review of the CT colonography images. Prior to the application of the wavelet-based postprocessor, the CTC CAD system detected 33 of the polyps (sensitivity 73.33%) with 12.4 false positives per patient, a sensitivity comparable to that of expert radiologists. Fourfold cross validation with 5000 bootstraps showed that the wavelet-based postprocessor could reduce the false positives by 56.61% (p <0.001), to 5.38 per patient (95% confidence interval [4.41, 6.34]), without significant sensitivity degradation (32/45, 71.11%, 95% confidence interval [66.39%, 75.74%], p=0.1713). We conclude that this wavelet-based postprocessor can substantially reduce the false positive rate of our CTC CAD for this important polyp size range.

Computer-aided diagnostic system for detection of Hashimoto thyroiditis on ultrasound images from a Polish population.

PubMed

Acharya, U Rajendra; Sree, S Vinitha; Krishnan, M Muthu Rama; Molinari, Filippo; Zieleźnik, Witold; Bardales, Ricardo H; Witkowska, Agnieszka; Suri, Jasjit S

2014-02-01

Computer-aided diagnostic (CAD) techniques aid physicians in better diagnosis of diseases by extracting objective and accurate diagnostic information from medical data. Hashimoto thyroiditis is the most common type of inflammation of the thyroid gland. The inflammation changes the structure of the thyroid tissue, and these changes are reflected as echogenic changes on ultrasound images. In this work, we propose a novel CAD system (a class of systems called ThyroScan) that extracts textural features from a thyroid sonogram and uses them to aid in the detection of Hashimoto thyroiditis. In this paradigm, we extracted grayscale features based on stationary wavelet transform from 232 normal and 294 Hashimoto thyroiditis-affected thyroid ultrasound images obtained from a Polish population. Significant features were selected using a Student t test. The resulting feature vectors were used to build and evaluate the following 4 classifiers using a 10-fold stratified cross-validation technique: support vector machine, decision tree, fuzzy classifier, and K-nearest neighbor. Using 7 significant features that characterized the textural changes in the images, the fuzzy classifier had the highest classification accuracy of 84.6%, sensitivity of 82.8%, specificity of 87.0%, and a positive predictive value of 88.9%. The proposed ThyroScan CAD system uses novel features to noninvasively detect the presence of Hashimoto thyroiditis on ultrasound images. Compared to manual interpretations of ultrasound images, the CAD system offers a more objective interpretation of the nature of the thyroid. The preliminary results presented in this work indicate the possibility of using such a CAD system in a clinical setting after evaluating it with larger databases in multicenter clinical trials.

A new data integration approach for AutoCAD and GIS

NASA Astrophysics Data System (ADS)

Ye, Hongmei; Li, Yuhong; Wang, Cheng; Li, Lijun

2006-10-01

GIS has its advantages both on spatial data analysis and management, particularly on the geometric and attributive information management, which has also attracted lots attentions among researchers around world. AutoCAD plays more and more important roles as one of the main data sources of GIS. Various work and achievements can be found in the related literature. However, the conventional data integration from AutoCAD to GIS is time-consuming, which also can cause the information loss both in the geometric aspects and the attributive aspects for a large system. It is necessary and urgent to sort out new approach and algorithm for the efficient high-quality data integration. In this paper, a novel data integration approach from AutoCAD to GIS will be introduced based on the spatial data mining technique through the data structure analysis both in the AutoCAD and GIS. A practicable algorithm for the data conversion from CAD to GIS will be given as well. By a designed evaluation scheme, the accuracy of the conversion both in the geometric and the attributive information will be demonstrated. Finally, the validity and feasibility of the new approach will be shown by an experimental analysis.

Deep learning in mammography and breast histology, an overview and future trends.

PubMed

Hamidinekoo, Azam; Denton, Erika; Rampun, Andrik; Honnor, Kate; Zwiggelaar, Reyer

2018-07-01

Recent improvements in biomedical image analysis using deep learning based neural networks could be exploited to enhance the performance of Computer Aided Diagnosis (CAD) systems. Considering the importance of breast cancer worldwide and the promising results reported by deep learning based methods in breast imaging, an overview of the recent state-of-the-art deep learning based CAD systems developed for mammography and breast histopathology images is presented. In this study, the relationship between mammography and histopathology phenotypes is described, which takes biological aspects into account. We propose a computer based breast cancer modelling approach: the Mammography-Histology-Phenotype-Linking-Model, which develops a mapping of features/phenotypes between mammographic abnormalities and their histopathological representation. Challenges are discussed along with the potential contribution of such a system to clinical decision making and treatment management. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

A review of intelligent systems for heart sound signal analysis.

PubMed

Nabih-Ali, Mohammed; El-Dahshan, El-Sayed A; Yahia, Ashraf S

2017-10-01

Intelligent computer-aided diagnosis (CAD) systems can enhance the diagnostic capabilities of physicians and reduce the time required for accurate diagnosis. CAD systems could provide physicians with a suggestion about the diagnostic of heart diseases. The objective of this paper is to review the recent published preprocessing, feature extraction and classification techniques and their state of the art of phonocardiogram (PCG) signal analysis. Published literature reviewed in this paper shows the potential of machine learning techniques as a design tool in PCG CAD systems and reveals that the CAD systems for PCG signal analysis are still an open problem. Related studies are compared to their datasets, feature extraction techniques and the classifiers they used. Current achievements and limitations in developing CAD systems for PCG signal analysis using machine learning techniques are presented and discussed. In the light of this review, a number of future research directions for PCG signal analysis are provided.

A flexible 3D laser scanning system using a robotic arm

NASA Astrophysics Data System (ADS)

Fei, Zixuan; Zhou, Xiang; Gao, Xiaofei; Zhang, Guanliang

2017-06-01

In this paper, we present a flexible 3D scanning system based on a MEMS scanner mounted on an industrial arm with a turntable. This system has 7-degrees of freedom and is able to conduct a full field scan from any angle, suitable for scanning object with the complex shape. The existing non-contact 3D scanning system usually uses laser scanner that projects fixed stripe mounted on the Coordinate Measuring Machine (CMM) or industrial robot. These existing systems can't perform path planning without CAD models. The 3D scanning system presented in this paper can scan the object without CAD models, and we introduced this path planning method in the paper. We also propose a practical approach to calibrating the hand-in-eye system based on binocular stereo vision and analyzes the errors of the hand-eye calibration.

Novel Cadmium Resistance Determinant in Listeria monocytogenes.

PubMed

Parsons, Cameron; Lee, Sangmi; Jayeola, Victor; Kathariou, Sophia

2017-03-01

Listeria monocytogenes is a foodborne pathogen that can cause severe disease (listeriosis) in susceptible individuals. It is ubiquitous in the environment and often exhibits resistance to heavy metals. One of the determinants that enables Listeria to tolerate exposure to cadmium is the cadAC efflux system, with CadA being a P-type ATPase. Three different cadA genes (designated cadA1 to cadA3 ) were previously characterized in L. monocytogenes A novel putative cadmium resistance gene ( cadA4 ) was recently identified through whole-genome sequencing, but experimental confirmation for its involvement in cadmium resistance is lacking. In this study, we characterized cadA4 in L. monocytogenes strain F8027, a cadmium-resistant strain of serotype 4b. By screening a mariner-based transposon library of this strain, we identified a mutant with reduced tolerance to cadmium and that harbored a single transposon insertion in cadA4 The tolerance to cadmium was restored by genetic complementation with the cadmium resistance cassette ( cadA4C ), and enhanced cadmium tolerance was conferred to two unrelated cadmium-sensitive strains via heterologous complementation with cadA4C Cadmium exposure induced cadA4 expression, even at noninhibitory levels. Virulence assessments in the Galleria mellonella model suggested that a functional cadA4 suppressed virulence, potentially promoting commensal colonization of the insect larvae. Biofilm assays suggested that cadA4 inactivation reduced biofilm formation. These data not only confirm cadA4 as a novel cadmium resistance determinant in L. monocytogenes but also provide evidence for roles in virulence and biofilm formation. IMPORTANCE Listeria monocytogenes is an intracellular foodborne pathogen causing the disease listeriosis, which is responsible for numerous hospitalizations and deaths every year. Among the adaptations that enable the survival of Listeria in the environment are the abilities to persist in biofilms, grow in the cold, and tolerate toxic compounds, such as heavy metals. Here, we characterized a novel determinant that was recently identified on a larger mobile genetic island through whole-genome sequencing. This gene ( cadA4 ) was found to be responsible for cadmium detoxification and to be a divergent member of the Cad family of cadmium efflux pumps. Virulence assessments in a Galleria mellonella model suggested that cadA4 may suppress virulence. Additionally, cadA4 may be involved in the ability of Listeria to form biofilms. Beyond the role in cadmium detoxification, the involvement of cadA4 in other cellular functions potentially explains its retention and wide distribution in L. monocytogenes . Copyright © 2017 American Society for Microbiology.

Exploring the color feature power for psoriasis risk stratification and classification: A data mining paradigm.

PubMed

Shrivastava, Vimal K; Londhe, Narendra D; Sonawane, Rajendra S; Suri, Jasjit S

2015-10-01

A large percentage of dermatologist׳s decision in psoriasis disease assessment is based on color. The current computer-aided diagnosis systems for psoriasis risk stratification and classification lack the vigor of color paradigm. The paper presents an automated psoriasis computer-aided diagnosis (pCAD) system for classification of psoriasis skin images into psoriatic lesion and healthy skin, which solves the two major challenges: (i) fulfills the color feature requirements and (ii) selects the powerful dominant color features while retaining high classification accuracy. Fourteen color spaces are discovered for psoriasis disease analysis leading to 86 color features. The pCAD system is implemented in a support vector-based machine learning framework where the offline image data set is used for computing machine learning offline color machine learning parameters. These are then used for transformation of the online color features to predict the class labels for healthy vs. diseased cases. The above paradigm uses principal component analysis for color feature selection of dominant features, keeping the original color feature unaltered. Using the cross-validation protocol, the above machine learning protocol is compared against the standalone grayscale features with 60 features and against the combined grayscale and color feature set of 146. Using a fixed data size of 540 images with equal number of healthy and diseased, 10 fold cross-validation protocol, and SVM of polynomial kernel of type two, pCAD system shows an accuracy of 99.94% with sensitivity and specificity of 99.93% and 99.96%. Using a varying data size protocol, the mean classification accuracies for color, grayscale, and combined scenarios are: 92.85%, 93.83% and 93.99%, respectively. The reliability of the system in these three scenarios are: 94.42%, 97.39% and 96.00%, respectively. We conclude that pCAD system using color space alone is compatible to grayscale space or combined color and grayscale spaces. We validated our pCAD system against facial color databases and the results are consistent in accuracy and reliability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Creation of system of computer-aided design for technological objects

NASA Astrophysics Data System (ADS)

Zubkova, T. M.; Tokareva, M. A.; Sultanov, N. Z.

2018-05-01

Due to the competition in the market of process equipment, its production should be flexible, retuning to various product configurations, raw materials and productivity, depending on the current market needs. This process is not possible without CAD (computer-aided design). The formation of CAD begins with planning. Synthesizing, analyzing, evaluating, converting operations, as well as visualization and decision-making operations, can be automated. Based on formal description of the design procedures, the design route in the form of an oriented graph is constructed. The decomposition of the design process, represented by the formalized description of the design procedures, makes it possible to make an informed choice of the CAD component for the solution of the task. The object-oriented approach allows us to consider the CAD as an independent system whose properties are inherited from the components. The first step determines the range of tasks to be performed by the system, and a set of components for their implementation. The second one is the configuration of the selected components. The interaction between the selected components is carried out using the CALS standards. The chosen CAD / CAE-oriented approach allows creating a single model, which is stored in the database of the subject area. Each of the integration stages is implemented as a separate functional block. The transformation of the CAD model into the model of the internal representation is realized by the block of searching for the geometric parameters of the technological machine, in which the XML-model of the construction is obtained on the basis of the feature method from the theory of image recognition. The configuration of integrated components is divided into three consecutive steps: configuring tasks, components, interfaces. The configuration of the components is realized using the theory of "soft computations" using the Mamdani fuzzy inference algorithm.

Pathologists' Computer-Assisted Diagnosis: A Mock-up of a Prototype Information System to Facilitate Automation of Pathology Sign-out.

PubMed

Farahani, Navid; Liu, Zheng; Jutt, Dylan; Fine, Jeffrey L

2017-10-01

- Pathologists' computer-assisted diagnosis (pCAD) is a proposed framework for alleviating challenges through the automation of their routine sign-out work. Currently, hypothetical pCAD is based on a triad of advanced image analysis, deep integration with heterogeneous information systems, and a concrete understanding of traditional pathology workflow. Prototyping is an established method for designing complex new computer systems such as pCAD. - To describe, in detail, a prototype of pCAD for the sign-out of a breast cancer specimen. - Deidentified glass slides and data from breast cancer specimens were used. Slides were digitized into whole-slide images with an Aperio ScanScope XT, and screen captures were created by using vendor-provided software. The advanced workflow prototype was constructed by using PowerPoint software. - We modeled an interactive, computer-assisted workflow: pCAD previews whole-slide images in the context of integrated, disparate data and predefined diagnostic tasks and subtasks. Relevant regions of interest (ROIs) would be automatically identified and triaged by the computer. A pathologist's sign-out work would consist of an interactive review of important ROIs, driven by required diagnostic tasks. The interactive session would generate a pathology report automatically. - Using animations and real ROIs, the pCAD prototype demonstrates the hypothetical sign-out in a stepwise fashion, illustrating various interactions and explaining how steps can be automated. The file is publicly available and should be widely compatible. This mock-up is intended to spur discussion and to help usher in the next era of digitization for pathologists by providing desperately needed and long-awaited automation.

Comparative characterization of a novel cad-cam polymer-infiltrated-ceramic-network

PubMed Central

Pascual, Agustín; Camps, Isabel; Grau-Benitez, María

2015-01-01

Background The field of dental ceramics for CAD-CAM is enriched with a new innovative material composition having a porous three-dimensional structure of feldspathic ceramic infiltrated with acrylic resins.The aim of this study is to determine the mechanical properties of Polymer-Infiltrated-Ceramic-Network (PICN) and compare its performance with other ceramics and a nano-ceramic resin available for CAD-CAM systems. Material and Methods In this study a total of five different materials for CAD-CAM were investigated. A polymer-infiltrated ceramic (Vita Enamic), a nano-ceramic resin (Lava Ultimate), a feldspathic ceramic (Mark II), a lithium disilicate ceramic (IPS-e max CAD) and finally a Leucite based ceramic (Empress - CAD). From CAD-CAM blocks, 120 bars (30 for each material cited above) were cut to measure the flexural strength with a three-point-bending test. Strain at failure, fracture stress and Weibull modulus was calculated. Vickers hardness of each material was also measured. Results IPS-EMAX presents mechanical properties significantly better from the other materials studied. Its strain at failure, flexural strength and hardness exhibited significantly higher values in comparison with the others. VITA ENAMIC and LAVA ULTIMATE stand out as the next most resistant materials. Conclusions The flexural strength, elastic modulus similar to a tooth as well as having less hardness than ceramics make PICN materials an option to consider as a restorative material. Key words:Ceramic infiltrated with resin, CAD-CAM, Weibull modulus, flexural strength, micro hardness. PMID:26535096

Modified Framingham Risk Factor Score for Systemic Lupus Erythematosus.

PubMed

Urowitz, Murray B; Ibañez, Dominique; Su, Jiandong; Gladman, Dafna D

2016-05-01

The traditional Framingham Risk Factor Score (FRS) underestimates the risk for coronary artery disease (CAD) in patients with systemic lupus erythematosus (SLE). We aimed to determine whether an adjustment to the FRS would more accurately reflect the higher prevalence of CAD among patients with SLE. Patients with SLE without a previous history of CAD or diabetes followed regularly at the University of Toronto Lupus Clinic were included. A modified FRS (mFRS) was calculated by multiplying the items by 1.5, 2, 3, or 4. In the first part of the study, using one-third of all eligible patients, we evaluated the sensitivity and specificity of the FRS and the different multipliers for the mFRS. In the second part of the study, using the remaining 2/3 of the eligible patients, we compared the predictive ability of the FRS to the mFRS. In the third part of the study, we assessed the prediction for CAD in a time-dependent analysis of the FRS and mFRS. There were 905 women (89.3%) with a total of 95 CAD events included. In part 1, we determined that a multiplier of 2 provided the best combination of sensitivity and specificity. In part 2, 2.4% of the patients were classified as moderate/high risk based on the classic FRS and 17.3% using the 2FRS (the FRS with a multiplier of 2). In part 3, a time-dependent covariate analysis for the prediction of the first CAD event revealed an HR of 3.22 (p = 0.07) for the classic FRS and 4.37 (p < 0.0001) for the 2FRS. An mFRS in which each item is multiplied by 2 more accurately predicts CAD in patients with SLE.

An adaptive incremental approach to constructing ensemble classifiers: application in an information-theoretic computer-aided decision system for detection of masses in mammograms.

PubMed

Mazurowski, Maciej A; Zurada, Jacek M; Tourassi, Georgia D

2009-07-01

Ensemble classifiers have been shown efficient in multiple applications. In this article, the authors explore the effectiveness of ensemble classifiers in a case-based computer-aided diagnosis system for detection of masses in mammograms. They evaluate two general ways of constructing subclassifiers by resampling of the available development dataset: Random division and random selection. Furthermore, they discuss the problem of selecting the ensemble size and propose two adaptive incremental techniques that automatically select the size for the problem at hand. All the techniques are evaluated with respect to a previously proposed information-theoretic CAD system (IT-CAD). The experimental results show that the examined ensemble techniques provide a statistically significant improvement (AUC = 0.905 +/- 0.024) in performance as compared to the original IT-CAD system (AUC = 0.865 +/- 0.029). Some of the techniques allow for a notable reduction in the total number of examples stored in the case base (to 1.3% of the original size), which, in turn, results in lower storage requirements and a shorter response time of the system. Among the methods examined in this article, the two proposed adaptive techniques are by far the most effective for this purpose. Furthermore, the authors provide some discussion and guidance for choosing the ensemble parameters.

CAD/CAM data management

NASA Technical Reports Server (NTRS)

Bray, O. H.

1984-01-01

The role of data base management in CAD/CAM, particularly for geometric data is described. First, long term and short term objectives for CAD/CAM data management are identified. Second, the benefits of the data base management approach are explained. Third, some of the additional work needed in the data base area is discussed.

Marker-based or model-based RSA for evaluation of hip resurfacing arthroplasty? A clinical validation and 5-year follow-up.

PubMed

Lorenzen, Nina Dyrberg; Stilling, Maiken; Jakobsen, Stig Storgaard; Gustafson, Klas; Søballe, Kjeld; Baad-Hansen, Thomas

2013-11-01

The stability of implants is vital to ensure a long-term survival. RSA determines micro-motions of implants as a predictor of early implant failure. RSA can be performed as a marker- or model-based analysis. So far, CAD and RE model-based RSA have not been validated for use in hip resurfacing arthroplasty (HRA). A phantom study determined the precision of marker-based and CAD and RE model-based RSA on a HRA implant. In a clinical study, 19 patients were followed with stereoradiographs until 5 years after surgery. Analysis of double-examination migration results determined the clinical precision of marker-based and CAD model-based RSA, and at the 5-year follow-up, results of the total translation (TT) and the total rotation (TR) for marker- and CAD model-based RSA were compared. The phantom study showed that comparison of the precision (SDdiff) in marker-based RSA analysis was more precise than model-based RSA analysis in TT (p CAD < 0.001; p RE = 0.04) and TR (p CAD = 0.01; p RE < 0.001). The clinical precision (double examination in 8 patients) comparing the precision SDdiff was better evaluating the TT using the marker-based RSA analysis (p = 0.002), but showed no difference between the marker- and CAD model-based RSA analysis regarding the TR (p = 0.91). Comparing the mean signed values regarding the TT and the TR at the 5-year follow-up in 13 patients, the TT was lower (p = 0.03) and the TR higher (p = 0.04) in the marker-based RSA compared to CAD model-based RSA. The precision of marker-based RSA was significantly better than model-based RSA. However, problems with occluded markers lead to exclusion of many patients which was not a problem with model-based RSA. HRA were stable at the 5-year follow-up. The detection limit was 0.2 mm TT and 1° TR for marker-based and 0.5 mm TT and 1° TR for CAD model-based RSA for HRA.

In Vitro Comparative Analysis of Fracture Resistance in Inlay Restoration Prepared with CAD-CAM and Different Systems in the Primary Teeth

PubMed Central

Derelioglu, Sera

2016-01-01

Objective. The aim of this study was to compare to fracture resistance test of inlay restorations prepared using direct inlay technique (Gradia® Direct Composite) and Indirect Restoration System® (Gradia Indirect Composite) and CAD/CAD system (Vita Enamic® Block). Study Design. 48 noncarious extracted maxillary second primary molars were randomly divided into 4 groups with 12 in each group. All the teeth were prepared based on inlay class II preparations except for the control group. Other groups were restored with Gradia Direct Composite, Gradia Indirect Composite, and Vita Enamic Block, respectively. All restorations were cemented self-adhesive dual cure resin (3M Espe, RelyX™ Unicem Aplicap). A fracture test was performed using a compressive load. Results were analyzed using one-way analysis of variance and Duncan's post hoc multiple comparison tests (α = 0.05). Results. Vita Enamic Block and Gradia Indirect Composite showed significantly higher fracture resistance than Gradia Direct Composite (p < 0.05). There was no significant difference fracture resistance between Vita Enamic Block and Gradia Indirect Composite (p > 0.05). All restorations tested led to a significant reduction in fracture resistance (p < 0.05). Conclusion. In inlay restorations, Indirect Restoration Systems and CAD/CAM systems were applied successfully together with the self-adhesive dual cure resin cements in primary molars. PMID:27830145

TGeoCad: an Interface between ROOT and CAD Systems

NASA Astrophysics Data System (ADS)

Luzzi, C.; Carminati, F.

2014-06-01

In the simulation of High Energy Physics experiment a very high precision in the description of the detector geometry is essential to achieve the required performances. The physicists in charge of Monte Carlo Simulation of the detector need to collaborate efficiently with the engineers working at the mechanical design of the detector. Often, this collaboration is made hard by the usage of different and incompatible software. ROOT is an object-oriented C++ framework used by physicists for storing, analyzing and simulating data produced by the high-energy physics experiments while CAD (Computer-Aided Design) software is used for mechanical design in the engineering field. The necessity to improve the level of communication between physicists and engineers led to the implementation of an interface between the ROOT geometrical modeler used by the virtual Monte Carlo simulation software and the CAD systems. In this paper we describe the design and implementation of the TGeoCad Interface that has been developed to enable the use of ROOT geometrical models in several CAD systems. To achieve this goal, the ROOT geometry description is converted into STEP file format (ISO 10303), which can be imported and used by many CAD systems.

Neural networks: Application to medical imaging

NASA Technical Reports Server (NTRS)

Clarke, Laurence P.

1994-01-01

The research mission is the development of computer assisted diagnostic (CAD) methods for improved diagnosis of medical images including digital x-ray sensors and tomographic imaging modalities. The CAD algorithms include advanced methods for adaptive nonlinear filters for image noise suppression, hybrid wavelet methods for feature segmentation and enhancement, and high convergence neural networks for feature detection and VLSI implementation of neural networks for real time analysis. Other missions include (1) implementation of CAD methods on hospital based picture archiving computer systems (PACS) and information networks for central and remote diagnosis and (2) collaboration with defense and medical industry, NASA, and federal laboratories in the area of dual use technology conversion from defense or aerospace to medicine.

CAD-based stand-alone spacecraft radiation exposure analysis system: An application of the early man-tended Space Station

NASA Technical Reports Server (NTRS)

Appleby, M. H.; Golightly, M. J.; Hardy, A. C.

1993-01-01

Major improvements have been completed in the approach to analyses and simulation of spacecraft radiation shielding and exposure. A computer-aided design (CAD)-based system has been developed for determining the amount of shielding provided by a spacecraft and simulating transmission of an incident radiation environment to any point within or external to the vehicle. Shielding analysis is performed using a customized ray-tracing subroutine contained within a standard engineering modeling software package. This improved shielding analysis technique has been used in several vehicle design programs such as a Mars transfer habitat, pressurized lunar rover, and the redesigned international Space Station. Results of analysis performed for the Space Station astronaut exposure assessment are provided to demonastrate the applicability and versatility of the system.

A Comparison of the Updated Diamond-Forrester, CAD Consortium, and CONFIRM History-Based Risk Scores for Predicting Obstructive Coronary Artery Disease in Patients With Stable Chest Pain: The SCOT-HEART Coronary CTA Cohort.

PubMed

Baskaran, Lohendran; Danad, Ibrahim; Gransar, Heidi; Ó Hartaigh, Bríain; Schulman-Marcus, Joshua; Lin, Fay Y; Peña, Jessica M; Hunter, Amanda; Newby, David E; Adamson, Philip D; Min, James K

2018-04-13

This study sought to compare the performance of history-based risk scores in predicting obstructive coronary artery disease (CAD) among patients with stable chest pain from the SCOT-HEART study. Risk scores for estimating pre-test probability of CAD are derived from referral-based populations with a high prevalence of disease. The generalizability of these scores to lower prevalence populations in the initial patient encounter for chest pain is uncertain. We compared 3 scores among patients with suspected CAD in the coronary computed tomographic angiography (CTA) randomized arm of the SCOT-HEART study for the outcome of obstructive CAD by coronary CTA: the updated Diamond-Forrester score (UDF), CAD Consortium clinical score (CAD2), and CONFIRM risk score (CRS). We tested calibration with goodness-of-fit, discrimination with area under the receiver-operating curve (AUC), and reclassification with net reclassification improvement (NRI) to identify low-risk patients. In 1,738 patients (58 ± 10 years and 44.0% women), overall calibration was best for UDF, with underestimation by CRS and CAD2. Discrimination by AUC was highest for CAD2 at 0.79 (95% confidence interval [CI]: 0.77 to 0.81) than for UDF (0.77 [95% CI: 0.74 to 0.79]) or CRS (0.75 [95% CI: 0.73 to 0.77]) (p < 0.001 for both comparisons). Reclassification of low-risk patients at the 10% probability threshold was best for CAD2 (NRI 0.31, 95% CI: 0.27 to 0.35) followed by CRS (NRI 0.21, 95% CI: 0.17 to 0.25) compared with UDF (p < 0.001 for all comparisons), with a consistent trend at the 15% threshold. In this multicenter clinic-based cohort of patients with suspected CAD and uniform CAD evaluation by coronary CTA, CAD2 provided the best discrimination and classification, despite overestimation of obstructive CAD as evaluated by coronary CTA. CRS exhibited intermediate performance followed by UDF for discrimination and reclassification. Copyright © 2018. Published by Elsevier Inc.

The burden of the variability introduced by the HEp-2 assay kit and the CAD system in ANA indirect immunofluorescence test.

PubMed

Infantino, M; Meacci, F; Grossi, V; Manfredi, M; Benucci, M; Merone, M; Soda, P

2017-02-01

According to the recent recommendations of the American College of Rheumatology, ANA Task Force, IIF technique should be considered the gold standard in antinuclear antibodies (ANAs) testing. To overcome the lack of standardization, biomedical industries have developed several computer-aided diagnosis (CAD) systems. Two hundred and sixty-one consecutive samples with suspected autoimmune diseases were tested for ANA by means of IIF on routinely HEp-2 assay kit (Euroimmun AG). Assignment of result was made if consensus for positive/negative was reached by at least 2 out of 3 expert physicians. ANA-IIF was also carried out using 3 CAD systems: Zenit G-Sight (n = 84), Helios (n = 85) and NOVA View (n = 92); human evaluation was repeated on the same substrate of each CAD system (Immco, Aesku and Inova HEp-2 cells, respectively). To anonymize the results, we randomly named these three systems as A, B and C. We ran a statistical analysis computing several measures of agreement between the ratings, and we also improved the evaluation by using the Wilcoxon's test for nonparametric data. Agreement between the human readings on routinely HEp-2 assay kit and human readings on CAD HEp-2 assay was substantial for A (k = 0.82) and B (k = 0.72), and almost perfect for C (k = 0.89). Such readings were statistically different only in case A. Comparing experts' readings with the readings of CAD systems, when the samples were prepared using CAD HEp-2 assay kits, we found almost perfect agreement for B and C (k = 0.86; k = 0.82) and substantial agreement for A (k = 0.73). Again, human and CAD readings were statistically different only in A. When we compared the readings of medical experts on routinely HEp-2 assay kit with the output of the CAD systems that worked using their own slides, we found substantial agreement for all the systems (A: k = 0.62; B: k = 0.65; C: k = 0.71). Such readings were not statistically different. The change of the assay kit and/or the introduction of a CAD system affect the laboratory reporting, with an evident impact on the autoimmune laboratory workflow. The CAD systems may represent one of the most important novel elements of harmonization in the autoimmunity field, reducing intra- and inter-laboratory variability in a new vision of the diagnostic autoimmune platform.

21 CFR 872.3661 - Optical Impression Systems for CAD/CAM.

Code of Federal Regulations, 2011 CFR

2011-04-01

... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3661 Optical Impression Systems for CAD... (CAD/CAM) is a device used to record the topographical characteristics of teeth, dental impressions, or stone models by analog or digital methods for use in the computer-assisted design and manufacturing of...

Adherence of Candida to complete denture surfaces in vitro: A comparison of conventional and CAD/CAM complete dentures

PubMed Central

Al-mejrad, Lamya A.; Albarrag, Ahmed M.

2017-01-01

PURPOSE The goal of this study was to compare the adhesion of Candida albicans to the surfaces of CAD/CAM and conventionally fabricated complete denture bases. MATERIALS AND METHODS Twenty discs of acrylic resin poly (methyl methacrylate) were fabricated with CAD/CAM and conventional procedures (heat-polymerized acrylic resin). The specimens were divided into two groups: 10 discs were fabricated using the CAD/CAM procedure (Wieland Digital Denture Ivoclar Vivadent), and 10 discs were fabricated using a conventional flasking and pressure-pack technique. Candida colonization was performed on all the specimens using four Candida albicans isolates. The difference in Candida albicans adhesion on the discs was evaluated. The number of adherent yeast cells was calculated by the colony-forming units (CFU) and by Fluorescence microscopy. RESULTS There was a significant difference in the adhesion of Candida albicans to the complete denture bases created with CAD/CAM and the adhesion to those created with the conventional procedure. The CAD/CAM denture bases exhibited less adhesion of Candida albicans than did the denture bases created with the conventional procedure (P<.05). CONCLUSION The CAD/CAM procedure for fabricating complete dentures showed promising potential for reducing the adherence of Candida to the denture base surface. Clinical Implications. Complete dentures made with the CAD/CAM procedure might decrease the incidence of denture stomatitis compared with conventional dentures. PMID:29142649

Adherence of Candida to complete denture surfaces in vitro: A comparison of conventional and CAD/CAM complete dentures.

PubMed

Al-Fouzan, Afnan F; Al-Mejrad, Lamya A; Albarrag, Ahmed M

2017-10-01

The goal of this study was to compare the adhesion of Candida albicans to the surfaces of CAD/CAM and conventionally fabricated complete denture bases. Twenty discs of acrylic resin poly (methyl methacrylate) were fabricated with CAD/CAM and conventional procedures (heat-polymerized acrylic resin). The specimens were divided into two groups: 10 discs were fabricated using the CAD/CAM procedure (Wieland Digital Denture Ivoclar Vivadent), and 10 discs were fabricated using a conventional flasking and pressure-pack technique. Candida colonization was performed on all the specimens using four Candida albicans isolates. The difference in Candida albicans adhesion on the discs was evaluated. The number of adherent yeast cells was calculated by the colony-forming units (CFU) and by Fluorescence microscopy. There was a significant difference in the adhesion of Candida albicans to the complete denture bases created with CAD/CAM and the adhesion to those created with the conventional procedure. The CAD/CAM denture bases exhibited less adhesion of Candida albicans than did the denture bases created with the conventional procedure ( P <.05). The CAD/CAM procedure for fabricating complete dentures showed promising potential for reducing the adherence of Candida to the denture base surface. Clinical Implications. Complete dentures made with the CAD/CAM procedure might decrease the incidence of denture stomatitis compared with conventional dentures.

Is Contrast Enhanced Ultrasonography a useful tool in a beginner's hand? How much can a Computer Assisted Diagnosis prototype help in characterizing the malignancy of focal liver lesions?

PubMed

Moga, Tudor Voicu; Popescu, Alina; Sporea, Ioan; Danila, Mirela; David, Ciprian; Gui, Vasile; Iacob, Nicoleta; Miclaus, Gratian; Sirli, Roxana

2017-08-23

Contrast enhanced ultrasound (CEUS) improved the characterization of focal liver lesions (FLLs), but is an operatordependent method. The goal of this paper was to test a computer assisted diagnosis (CAD) prototype and to see its benefit in assisting a beginner in the evaluation of FLLs. Our cohort included 97 good quality CEUS videos[34% hepatocellular carcinomas (HCC), 12.3% hypervascular metastases (HiperM), 11.3% hypovascular metastases (HipoM), 24.7% hemangiomas (HMG), 17.5% focal nodular hyperplasia (FNH)] that were used to develop a CAD prototype based on an algorithm that tested a binary decision based classifier. Two young medical doctors (1 year CEUS experience), two experts and the CAD prototype, reevaluated 50 FLLs CEUS videos (diagnosis of benign vs. malignant) first blinded to clinical data, in order to evaluate the diagnostic gap beginner vs. expert. The CAD classifier managed a 75.2% overall (benign vs. malignant) correct classification rate. The overall classification rates for the evaluators, before and after clinical data were: first beginner-78%; 94%; second beginner-82%; 96%; first expert-94%; 100%; second expert-96%; 98%. For both beginners, the malignant vs. benign diagnosis significantly improved after knowing the clinical data (p=0.005; p=0,008). The expert was better than the beginner (p=0.04) and better than the CAD (p=0.001). CAD in addition to the beginner can reach the expert diagnosis. The most frequent lesions misdiagnosed at CEUS were FNH and HCC. The CAD prototype is a good comparing tool for a beginner operator that can be developed to assist the diagnosis. In order to increase the classification rate, the CAD system for FLL in CEUS must integrate the clinical data.

Particle tracking acceleration via signed distance fields in direct-accelerated geometry Monte Carlo

DOE PAGES

Shriwise, Patrick C.; Davis, Andrew; Jacobson, Lucas J.; ...

2017-08-26

Computer-aided design (CAD)-based Monte Carlo radiation transport is of value to the nuclear engineering community for its ability to conduct transport on high-fidelity models of nuclear systems, but it is more computationally expensive than native geometry representations. This work describes the adaptation of a rendering data structure, the signed distance field, as a geometric query tool for accelerating CAD-based transport in the direct-accelerated geometry Monte Carlo toolkit. Demonstrations of its effectiveness are shown for several problems. The beginnings of a predictive model for the data structure's utilization based on various problem parameters is also introduced.

A smartphone photogrammetry method for digitizing prosthetic socket interiors.

PubMed

Hernandez, Amaia; Lemaire, Edward

2017-04-01

Prosthetic CAD/CAM systems require accurate 3D limb models; however, difficulties arise when working from the person's socket since current 3D scanners have difficulties scanning socket interiors. While dedicated scanners exist, they are expensive and the cost may be prohibitive for a limited number of scans per year. A low-cost and accessible photogrammetry method for socket interior digitization is proposed, using a smartphone camera and cloud-based photogrammetry services. 15 two-dimensional images of the socket's interior are captured using a smartphone camera. A 3D model is generated using cloud-based software. Linear measurements were comparing between sockets and the related 3D models. 3D reconstruction accuracy averaged 2.6 ± 2.0 mm and 0.086 ± 0.078 L, which was less accurate than models obtained by high quality 3D scanners. However, this method would provide a viable 3D digital socket reproduction that is accessible and low-cost, after processing in prosthetic CAD software. Clinical relevance The described method provides a low-cost and accessible means to digitize a socket interior for use in prosthetic CAD/CAM systems, employing a smartphone camera and cloud-based photogrammetry software.

A ROC-based feature selection method for computer-aided detection and diagnosis

NASA Astrophysics Data System (ADS)

Wang, Songyuan; Zhang, Guopeng; Liao, Qimei; Zhang, Junying; Jiao, Chun; Lu, Hongbing

2014-03-01

Image-based computer-aided detection and diagnosis (CAD) has been a very active research topic aiming to assist physicians to detect lesions and distinguish them from benign to malignant. However, the datasets fed into a classifier usually suffer from small number of samples, as well as significantly less samples available in one class (have a disease) than the other, resulting in the classifier's suboptimal performance. How to identifying the most characterizing features of the observed data for lesion detection is critical to improve the sensitivity and minimize false positives of a CAD system. In this study, we propose a novel feature selection method mR-FAST that combines the minimal-redundancymaximal relevance (mRMR) framework with a selection metric FAST (feature assessment by sliding thresholds) based on the area under a ROC curve (AUC) generated on optimal simple linear discriminants. With three feature datasets extracted from CAD systems for colon polyps and bladder cancer, we show that the space of candidate features selected by mR-FAST is more characterizing for lesion detection with higher AUC, enabling to find a compact subset of superior features at low cost.

Thermogram breast cancer prediction approach based on Neutrosophic sets and fuzzy c-means algorithm.

PubMed

Gaber, Tarek; Ismail, Gehad; Anter, Ahmed; Soliman, Mona; Ali, Mona; Semary, Noura; Hassanien, Aboul Ella; Snasel, Vaclav

2015-08-01

The early detection of breast cancer makes many women survive. In this paper, a CAD system classifying breast cancer thermograms to normal and abnormal is proposed. This approach consists of two main phases: automatic segmentation and classification. For the former phase, an improved segmentation approach based on both Neutrosophic sets (NS) and optimized Fast Fuzzy c-mean (F-FCM) algorithm was proposed. Also, post-segmentation process was suggested to segment breast parenchyma (i.e. ROI) from thermogram images. For the classification, different kernel functions of the Support Vector Machine (SVM) were used to classify breast parenchyma into normal or abnormal cases. Using benchmark database, the proposed CAD system was evaluated based on precision, recall, and accuracy as well as a comparison with related work. The experimental results showed that our system would be a very promising step toward automatic diagnosis of breast cancer using thermograms as the accuracy reached 100%.

Comparison of Flexural Strength of Different CAD/CAM PMMA-Based Polymers.

PubMed

Alp, Gülce; Murat, Sema; Yilmaz, Burak

2018-01-28

To compare the flexural strength of different computer-aided design/computer-aided manufacturing (CAD/CAM) poly(methyl methacrylate)-based (PMMA) polymers and conventional interim resin materials after thermocycling. Rectangular-shaped specimens (n = 15, for each material) (25 × 2 × 2 mm 3 ) were fabricated from 3 CAD/CAM PMMA-based polymers (Telio CAD [T]; M-PM-Disc [M]; Polident-PMMA [P]), 1 bis-acrylate composite resin (Protemp 4 [PT]), and 1 conventional PMMA (ArtConcept Artegral Dentine [C]) according to ISO 10477:2004 Standards (Dentistry-Polymer-Based Crown and Bridge Materials). The specimens were subjected to 10,000 thermocycles (5 to 55°C). Three-point flexural strength of the specimens was tested in a universal testing machine at a 1.0 mm/min crosshead speed, and the flexural strength data (σ) were calculated (MPa). The flexural strength values were statistically analyzed using 1-way ANOVA, and Tukey HSD post-hoc test for multiple comparisons (α = 0.05). Flexural strength values ranged between 66.1 ± 13.1 and 131.9 ± 19.8 MPa. There were significant differences among the flexural strengths of tested materials, except for between T and P CAD/CAM PMMA-based polymers (p > 0.05). CAD/CAM PMMA-based polymer M had the highest flexural strength and conventional PMMA had the lowest (p < 0.05). CAD/CAM PMMA-based T and P polymers had significantly higher flexural strength than the bis-acrylate composite resin (p < 0.05), and conventional PMMA (p < 0.0001), and significantly lower flexural strength compared to CAD/CAM PMMA-based M (p < 0.05). The flexural strength of CAD/CAM PMMA-based polymers was greater than the flexural strength of bis-acrylate composite resin, which had a greater flexural strength compared to conventional PMMA resin. © 2018 by the American College of Prosthodontists.

Repairability of CAD/CAM high-density PMMA- and composite-based polymers.

PubMed

Wiegand, Annette; Stucki, Lukas; Hoffmann, Robin; Attin, Thomas; Stawarczyk, Bogna

2015-11-01

The study aimed to analyse the shear bond strength of computer-aided design and computer-aided manufacturing (CAD/CAM) polymethyl methacrylate (PMMA)- and composite-based polymer materials repaired with a conventional methacrylate-based composite after different surface pretreatments. Each 48 specimens was prepared from six different CAD/CAM polymer materials (Ambarino high-class, artBloc Temp, CAD-Temp, Lava Ultimate, Telio CAD, Everest C-Temp) and a conventional dimethacrylate-based composite (Filtek Supreme XTE, control) and aged by thermal cycling (5000 cycles, 5-55 °C). The surfaces were left untreated or were pretreated by mechanical roughening, aluminium oxide air abrasion or silica coating/silanization (each subgroup n = 12). The surfaces were further conditioned with an etch&rinse adhesive (OptiBond FL) before the repair composite (Filtek Supreme XTE) was adhered to the surface. After further thermal cycling, shear bond strength was tested, and failure modes were assessed. Shear bond strength was statistically analysed by two- and one-way ANOVAs and Weibull statistics, failure mode by chi(2) test (p ≤ 0.05). Shear bond strength was highest for silica coating/silanization > aluminium oxide air abrasion = mechanical roughening > no surface pretreatment. Independently of the repair pretreatment, highest bond strength values were observed in the control group and for the composite-based Everest C-Temp and Ambarino high-class, while PMMA-based materials (artBloc Temp, CAD-Temp and Telio CAD) presented significantly lowest values. For all materials, repair without any surface pretreatment resulted in adhesive failures only, which mostly were reduced when surface pretreatment was performed. Repair of CAD/CAM high-density polymers requires surface pretreatment prior to adhesive and composite application. However, four out of six of the tested CAD/CAM materials did not achieve the repair bond strength of a conventional dimethacrylate-based composite. Repair of PMMA- and composite-based polymers can be achieved by surface pretreatment followed by application of an adhesive and a conventional methacrylate-based composite.

Structured reporting platform improves CAD-RADS assessment.

PubMed

Szilveszter, Bálint; Kolossváry, Márton; Karády, Júlia; Jermendy, Ádám L; Károlyi, Mihály; Panajotu, Alexisz; Bagyura, Zsolt; Vecsey-Nagy, Milán; Cury, Ricardo C; Leipsic, Jonathon A; Merkely, Béla; Maurovich-Horvat, Pál

2017-11-01

Structured reporting in cardiac imaging is strongly encouraged to improve quality through consistency. The Coronary Artery Disease - Reporting and Data System (CAD-RADS) was recently introduced to facilitate interdisciplinary communication of coronary CT angiography (CTA) results. We aimed to assess the agreement between manual and automated CAD-RADS classification using a structured reporting platform. Five readers prospectively interpreted 500 coronary CT angiographies using a structured reporting platform that automatically calculates the CAD-RADS score based on stenosis and plaque parameters manually entered by the reader. In addition, all readers manually assessed CAD-RADS blinded to the automatically derived results, which was used as the reference standard. We evaluated factors influencing reader performance including CAD-RADS training, clinical load, time of the day and level of expertise. Total agreement between manual and automated classification was 80.2%. Agreement in stenosis categories was 86.7%, whereas the agreement in modifiers was 95.8% for "N", 96.8% for "S", 95.6% for "V" and 99.4% for "G". Agreement for V improved after CAD-RADS training (p = 0.047). Time of the day and clinical load did not influence reader performance (p > 0.05 both). Less experienced readers had a higher total agreement as compared to more experienced readers (87.0% vs 78.0%, respectively; p = 0.011). Even though automated CAD-RADS classification uses data filled in by the readers, it outperforms manual classification by preventing human errors. Structured reporting platforms with automated calculation of the CAD-RADS score might improve data quality and support standardization of clinical decision making. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

B-Spline Filtering for Automatic Detection of Calcification Lesions in Mammograms

NASA Astrophysics Data System (ADS)

Bueno, G.; Sánchez, S.; Ruiz, M.

2006-10-01

Breast cancer continues to be an important health problem between women population. Early detection is the only way to improve breast cancer prognosis and significantly reduce women mortality. It is by using CAD systems that radiologist can improve their ability to detect, and classify lesions in mammograms. In this study the usefulness of using B-spline based on a gradient scheme and compared to wavelet and adaptative filtering has been investigated for calcification lesion detection and as part of CAD systems. The technique has been applied to different density tissues. A qualitative validation shows the success of the method.

Computer-aided-diagnosis (CAD) for colposcopy

NASA Astrophysics Data System (ADS)

Lange, Holger; Ferris, Daron G.

2005-04-01

Uterine cervical cancer is the second most common cancer among women worldwide. Colposcopy is a diagnostic method, whereby a physician (colposcopist) visually inspects the lower genital tract (cervix, vulva and vagina), with special emphasis on the subjective appearance of metaplastic epithelium comprising the transformation zone on the cervix. Cervical cancer precursor lesions and invasive cancer exhibit certain distinctly abnormal morphologic features. Lesion characteristics such as margin; color or opacity; blood vessel caliber, intercapillary spacing and distribution; and contour are considered by colposcopists to derive a clinical diagnosis. Clinicians and academia have suggested and shown proof of concept that automated image analysis of cervical imagery can be used for cervical cancer screening and diagnosis, having the potential to have a direct impact on improving women"s health care and reducing associated costs. STI Medical Systems is developing a Computer-Aided-Diagnosis (CAD) system for colposcopy -- ColpoCAD. At the heart of ColpoCAD is a complex multi-sensor, multi-data and multi-feature image analysis system. A functional description is presented of the envisioned ColpoCAD system, broken down into: Modality Data Management System, Image Enhancement, Feature Extraction, Reference Database, and Diagnosis and directed Biopsies. The system design and development process of the image analysis system is outlined. The system design provides a modular and open architecture built on feature based processing. The core feature set includes the visual features used by colposcopists. This feature set can be extended to include new features introduced by new instrument technologies, like fluorescence and impedance, and any other plausible feature that can be extracted from the cervical data. Preliminary results of our research on detecting the three most important features: blood vessel structures, acetowhite regions and lesion margins are shown. As this is a new and very complex field in medical image processing, the hope is that this paper can provide a framework and basis to encourage and facilitate collaboration and discussion between industry, academia, and medical practitioners.

Predicting Long-term Ischemic Events Using Routine Clinical Parameters in Patients with Coronary Artery Disease: The OPT-CAD Risk Score.

PubMed

Han, Yaling; Chen, Jiyan; Qiu, Miaohan; Li, Yi; Li, Jing; Feng, Yingqing; Qiu, Jian; Meng, Liang; Sun, Yihong; Tao, Guizhou; Wu, Zhaohui; Yang, Chunyu; Guo, Jincheng; Pu, Kui; Chen, Shaoliang; Wang, Xiaozeng

2018-06-05

The prognosis of patients with coronary artery disease (CAD) at hospital discharge was constantly varying, and post-discharge risk of ischemic events remain a concern. However, risk prediction tools to identify risk of ischemia for these patients has not yet been reported. We sought to develop a scoring system for predicting long-term ischemic events in CAD patients receiving antiplatelet therapy that would be beneficial in appropriate personalized decision-making for these patients. In this prospective Optimal antiPlatelet Therapy for Chinese patients with Coronary Artery Disease (OPT-CAD, NCT01735305) registry, a total of 14,032 patients with CAD receiving at least one kind of antiplatelet agent were enrolled from 107 centers across China, from January 2012 to March 2014. The risk scoring system was developed in a derivation cohort (enrolled initially 10,000 patients in the database) using a logistic regression model and was subsequently tested in a validation cohort (the last 4,032 patients). Points in risk score was assigned based on the multivariable odds ratio of each factor. Ischemic events were defined as the composite of cardiac death, myocardial infarction or stroke. Ischemic events occurred in 342 (3.4%) patients in the derivation cohort and 160 (4.0%) patients in the validation cohort during 1-year follow-up. The OPT-CAD score, ranging from 0-257 points, consist of 10 independent risk factors, including age (0-71 points), heart rates (0-36 points), hypertension (0-20 points), prior myocardial infarction (16 points), prior stroke (16 points), renal insufficient (21 points), anemia (19 points), low ejection fraction (22 points), positive cardiac troponin (23 points) and ST-segment deviation (13 points). In predicting 1-year ischemic events, the area under receiver operating characteristics curve were 0.73 and 0.72 in derivation and validation cohort, respectively. The incidences of ischemic events in low- (0-90 points), medium- (91-150 points) and high-risk (≥151 points) patients were 1.6%, 5.5%, and 15.0%, respectively. Compared to GRACE score, OPT-CAD score had a better discrimination in predicting ischemic events and all-cause mortality (ischemic events: 0.72 vs 0.65, all-cause mortality: 0.79 vs 0.72, both P<0.001). Among CAD patients, a risk score based on 10 baseline clinical variables performed better than the GRACE risk score in predicting long-term ischemic events. However, further research is needed to assess the value of the OPT-CAD score in guiding the management of antiplatelet therapy for patients with CAD. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Foundation and methodologies in computer-aided diagnosis systems for breast cancer detection.

PubMed

Jalalian, Afsaneh; Mashohor, Syamsiah; Mahmud, Rozi; Karasfi, Babak; Saripan, M Iqbal B; Ramli, Abdul Rahman B

2017-01-01

Breast cancer is the most prevalent cancer that affects women all over the world. Early detection and treatment of breast cancer could decline the mortality rate. Some issues such as technical reasons, which related to imaging quality and human error, increase misdiagnosis of breast cancer by radiologists. Computer-aided detection systems (CADs) are developed to overcome these restrictions and have been studied in many imaging modalities for breast cancer detection in recent years. The CAD systems improve radiologists' performance in finding and discriminating between the normal and abnormal tissues. These procedures are performed only as a double reader but the absolute decisions are still made by the radiologist. In this study, the recent CAD systems for breast cancer detection on different modalities such as mammography, ultrasound, MRI, and biopsy histopathological images are introduced. The foundation of CAD systems generally consist of four stages: Pre-processing, Segmentation, Feature extraction, and Classification. The approaches which applied to design different stages of CAD system are summarised. Advantages and disadvantages of different segmentation, feature extraction and classification techniques are listed. In addition, the impact of imbalanced datasets in classification outcomes and appropriate methods to solve these issues are discussed. As well as, performance evaluation metrics for various stages of breast cancer detection CAD systems are reviewed.

Foundation and methodologies in computer-aided diagnosis systems for breast cancer detection

PubMed Central

Jalalian, Afsaneh; Mashohor, Syamsiah; Mahmud, Rozi; Karasfi, Babak; Saripan, M. Iqbal B.; Ramli, Abdul Rahman B.

2017-01-01

Breast cancer is the most prevalent cancer that affects women all over the world. Early detection and treatment of breast cancer could decline the mortality rate. Some issues such as technical reasons, which related to imaging quality and human error, increase misdiagnosis of breast cancer by radiologists. Computer-aided detection systems (CADs) are developed to overcome these restrictions and have been studied in many imaging modalities for breast cancer detection in recent years. The CAD systems improve radiologists' performance in finding and discriminating between the normal and abnormal tissues. These procedures are performed only as a double reader but the absolute decisions are still made by the radiologist. In this study, the recent CAD systems for breast cancer detection on different modalities such as mammography, ultrasound, MRI, and biopsy histopathological images are introduced. The foundation of CAD systems generally consist of four stages: Pre-processing, Segmentation, Feature extraction, and Classification. The approaches which applied to design different stages of CAD system are summarised. Advantages and disadvantages of different segmentation, feature extraction and classification techniques are listed. In addition, the impact of imbalanced datasets in classification outcomes and appropriate methods to solve these issues are discussed. As well as, performance evaluation metrics for various stages of breast cancer detection CAD systems are reviewed. PMID:28435432

21 CFR 872.3661 - Optical Impression Systems for CAD/CAM.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Optical Impression Systems for CAD/CAM. 872.3661 Section 872.3661 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Design and Manufacturing (CAD/CAM) of Dental Restorations; Guidance for Industry and FDA.” For the...

A new approach of objective quality evaluation on JPEG2000 lossy-compressed lung cancer CT images

NASA Astrophysics Data System (ADS)

Cai, Weihua; Tan, Yongqiang; Zhang, Jianguo

2007-03-01

Image compression has been used to increase the communication efficiency and storage capacity. JPEG 2000 compression, based on the wavelet transformation, has its advantages comparing to other compression methods, such as ROI coding, error resilience, adaptive binary arithmetic coding and embedded bit-stream. However it is still difficult to find an objective method to evaluate the image quality of lossy-compressed medical images so far. In this paper, we present an approach to evaluate the image quality by using a computer aided diagnosis (CAD) system. We selected 77 cases of CT images, bearing benign and malignant lung nodules with confirmed pathology, from our clinical Picture Archiving and Communication System (PACS). We have developed a prototype of CAD system to classify these images into benign ones and malignant ones, the performance of which was evaluated by the receiver operator characteristics (ROC) curves. We first used JPEG 2000 to compress these cases of images with different compression ratio from lossless to lossy, and used the CAD system to classify the cases with different compressed ratio, then compared the ROC curves from the CAD classification results. Support vector machine (SVM) and neural networks (NN) were used to classify the malignancy of input nodules. In each approach, we found that the area under ROC (AUC) decreases with the increment of compression ratio with small fluctuations.

The clinical evaluation of the CADence device in the acoustic detection of coronary artery disease.

PubMed

Thomas, Joseph L; Ridner, Michael; Cole, Jason H; Chambers, Jeffrey W; Bokhari, Sabahat; Yannopoulos, Demetris; Kern, Morton; Wilson, Robert F; Budoff, Matthew J

2018-06-23

The noninvasive detection of turbulent coronary flow may enable diagnosis of significant coronary artery disease (CAD) using novel sensor and analytic technology. Eligible patients (n = 1013) with chest pain and CAD risk factors undergoing nuclear stress testing were studied using the CADence (AUM Cardiovascular Inc., Northfield MN) acoustic detection (AD) system. The trial was designed to demonstrate non-inferiority of AD for diagnostic accuracy in detecting significant CAD as compared to an objective performance criteria (sensitivity 83% and specificity 80%, with 15% non-inferiority margins) for nuclear stress testing. AD analysis was blinded to clinical, core lab-adjudicated angiographic, and nuclear data. The presence of significant CAD was determined by computed tomographic (CCTA) or invasive angiography. A total of 1013 subjects without prior coronary revascularization or Q-wave myocardial infarction were enrolled. Primary analysis was performed on subjects with complete angiographic and AD data (n = 763) including 111 subjects (15%) with severe CAD based on CCTA (n = 34) and invasive angiography (n = 77). The sensitivity and specificity of AD were 78% (p = 0.012 for non-inferiority) and 35% (p < 0.001 for failure to demonstrate non-inferiority), respectively. AD results had a high 91% negative predictive value for the presence of significant CAD. AD testing failed to demonstrate non-inferior diagnostic accuracy as compared to the historical performance of a nuclear stress OPC due to low specificity. AD sensitivity was non-inferior in detecting significant CAD with a high negative predictive value supporting a potential value in excluding CAD.

Education and Training Packages for CAD/CAM.

ERIC Educational Resources Information Center

Wright, I. C.

1986-01-01

Discusses educational efforts in the fields of Computer Assisted Design and Manufacturing (CAD/CAM). Describes two educational training initiatives underway in the United Kingdom, one of which is a resource materials package for teachers of CAD/CAM at the undergraduate level, and the other a training course for managers of CAD/CAM systems. (TW)

Computed-aided diagnosis (CAD) in the detection of breast cancer.

PubMed

Dromain, C; Boyer, B; Ferré, R; Canale, S; Delaloge, S; Balleyguier, C

2013-03-01

Computer-aided detection (CAD) systems have been developed for interpretation to improve mammographic detection of breast cancer at screening by reducing the number of false-negative interpretation that can be caused by subtle findings, radiologist distraction and complex architecture. They use a digitized mammographic image that can be obtained from both screen-film mammography and full field digital mammography. Its performance in breast cancer detection is dependent on the performance of the CAD itself, the population to which it is applied and the radiologists who use it. There is a clear benefit to the use of CAD in less experienced radiologist and in detecting breast carcinomas presenting as microcalcifications. This review gives a detailed description CAD systems used in mammography and their performance in assistance of reading in screening mammography and as an alternative to double reading. Other CAD systems developed for MRI and ultrasound are also presented and discussed. Copyright © 2012. Published by Elsevier Ireland Ltd.

Marginal and internal fits of fixed dental prostheses zirconia retainers.

PubMed

Beuer, Florian; Aggstaller, Hans; Edelhoff, Daniel; Gernet, Wolfgang; Sorensen, John

2009-01-01

CAM (computer-aided manufacturing) and CAD (computer-aided design)/CAM systems facilitate the use of zirconia substructure materials for all-ceramic fixed partial dentures. This in vitro study compared the precision of fit of frameworks milled from semi-sintered zirconia blocks that were designed and machined with two CAD/CAM and one CAM system. Three-unit posterior fixed dental prostheses (FDP) (n=10) were fabricated for standardized dies by: a milling center CAD/CAM system (Etkon), a laboratory CAD/CAM system (Cerec InLab), and a laboratory CAM system (Cercon). After adaptation by a dental technician, the FDP were cemented on definitive dies, embedded and sectioned. The marginal and internal fits were measured under an optical microscope at 50x magnification. A one-way analysis of variance (ANOVA) was used to compare data (alpha=0.05). The mean (S.D.) for the marginal fit and internal fit adaptation were: 29.1 microm (14.0) and 62.7 microm (18.9) for the milling center system, 56.6 microm (19.6) and 73.5 microm (20.6) for the laboratory CAD/CAM system, and 81.4 microm (20.3) and 119.2 microm (37.5) for the laboratory CAM system. One-way ANOVA showed significant differences between systems for marginal fit (P<0.001) and internal fit (P<0.001). All systems showed marginal gaps below 120 microm and were therefore considered clinically acceptable. The CAD/CAM systems were more precise than the CAM system.

Towards a behavioral-matching based compilation of synthetic biology functions.

PubMed

Basso-Blandin, Adrien; Delaplace, Franck

2015-09-01

The field of synthetic biology is looking forward engineering framework for safely designing reliable de-novo biological functions. In this undertaking, Computer-Aided-Design (CAD) environments should play a central role for facilitating the design. Although, CAD environment is widely used to engineer artificial systems the application in synthetic biology is still in its infancy. In this article we address the problem of the design of a high level language which at the core of CAD environment. More specifically the Gubs (Genomic Unified Behavioural Specification) language is a specification language used to describe the observations of the expected behaviour. The compiler appropriately selects components such that the observation of the synthetic biological function resulting to their assembly complies to the programmed behaviour.

Marginal and internal discrepancies of zirconia copings: effects of milling system and finish line design.

PubMed

Ribeiro, Isabella Lima Arrais; Campos, Fernanda; Sousa, Rafael Santiago; Alves, Maria Luiza Lima; Rodrigues, Dalton Matos; Souza, Rodrigo Othavio Assuncão; Bottino, Marco Antonio

2015-01-01

Discrepancies at the abutment/crown interface can affect the longevity of zirconia restorations. The aim was to evaluate the marginal and internal discrepancies (MD and ID) of zirconia copings manufactured by two milling systems with different finish lines. Three aluminum-master-dies (h = 5.5 mm; Ψ =7.5 mm; 6΀), with different finish lines (large chamfer [LC]; tilted chamfer [TC]; rounded shoulder [RS]) were fabricated. Twenty impressions were made from each master die and poured. Sixty zirconia copings were manufactured and divided according to the factors "finish line" and "milling system" (n = 10): CAD LC = Computer-aided design/computer-aided manufacturing (CAD/CAM) + LC; CAD TC = CAD/CAM + TC; CAD RS = CAD/CAM + RS; MAD LC = manually aided design/manually aided manufacturing (MAD/MAM) + LC; MAD TC = MAD/MAM + TC; and MAD RS = MAD/MAM + RS. For MD analysis, each coping was fixed, and the distance between the external edges of the coping and the edge of the cervical preparation was measured (50 points). Using the same copings, the ID of each coping was evaluated, by the replica technique, at 12 points equally distributed among the regions (n = 10): Ray (R), axial (A), and occlusal (Occl). The measurements were performed by optical microscopy (Χ250). The data (μm) were subjected to parametric and non-parametric statistical analyses. For the MAD/MAM system, the "finish line" (P = 0.0001) affected significantly the MD median values (μm): LC = 251.80 a , RS = 68.40 a and TC = 8.10 b (Dunn's test). For the CAD/CAM system, the median MD values (μm) were not affected by the factor "finish line" (P = 0.4037): LC = 0.82 a , RS = 0.52 a , and TC = 0.89 a . For the ID, it was observed interaction between the finish line types and the region (P = 0.0001) and between region and milling system (P = 0.0031) (RM-ANOVA). The CAD/CAM system presented lower MD values, regardless the finish line. However, the MAD/MAM system showed ID values smaller than those of CAD/CAM.

High frame rate imaging systems developed in Northwest Institute of Nuclear Technology

NASA Astrophysics Data System (ADS)

Li, Binkang; Wang, Kuilu; Guo, Mingan; Ruan, Linbo; Zhang, Haibing; Yang, Shaohua; Feng, Bing; Sun, Fengrong; Chen, Yanli

2007-01-01

This paper presents high frame rate imaging systems developed in Northwest Institute of Nuclear Technology in recent years. Three types of imaging systems are included. The first type of system utilizes EG&G RETICON Photodiode Array (PDA) RA100A as the image sensor, which can work at up to 1000 frame per second (fps). Besides working continuously, the PDA system is also designed to switch to capture flash light event working mode. A specific time sequence is designed to satisfy this request. The camera image data can be transmitted to remote area by coaxial or optic fiber cable and then be stored. The second type of imaging system utilizes PHOTOBIT Complementary Metal Oxygen Semiconductor (CMOS) PB-MV13 as the image sensor, which has a high resolution of 1280 (H) ×1024 (V) pixels per frame. The CMOS system can operate at up to 500fps in full frame and 4000fps partially. The prototype scheme of the system is presented. The third type of imaging systems adopts charge coupled device (CCD) as the imagers. MINTRON MTV-1881EX, DALSA CA-D1 and CA-D6 camera head are used in the systems development. The features comparison of the RA100A, PB-MV13, and CA-D6 based systems are given in the end.

A deep-learning based automatic pulmonary nodule detection system

NASA Astrophysics Data System (ADS)

Zhao, Yiyuan; Zhao, Liang; Yan, Zhennan; Wolf, Matthias; Zhan, Yiqiang

2018-02-01

Lung cancer is the deadliest cancer worldwide. Early detection of lung cancer is a promising way to lower the risk of dying. Accurate pulmonary nodule detection in computed tomography (CT) images is crucial for early diagnosis of lung cancer. The development of computer-aided detection (CAD) system of pulmonary nodules contributes to making the CT analysis more accurate and with more efficiency. Recent studies from other groups have been focusing on lung cancer diagnosis CAD system by detecting medium to large nodules. However, to fully investigate the relevance between nodule features and cancer diagnosis, a CAD that is capable of detecting nodules with all sizes is needed. In this paper, we present a deep-learning based automatic all size pulmonary nodule detection system by cascading two artificial neural networks. We firstly use a U-net like 3D network to generate nodule candidates from CT images. Then, we use another 3D neural network to refine the locations of the nodule candidates generated from the previous subsystem. With the second sub-system, we bring the nodule candidates closer to the center of the ground truth nodule locations. We evaluate our system on a public CT dataset provided by the Lung Nodule Analysis (LUNA) 2016 grand challenge. The performance on the testing dataset shows that our system achieves 90% sensitivity with an average of 4 false positives per scan. This indicates that our system can be an aid for automatic nodule detection, which is beneficial for lung cancer diagnosis.

Effect of Finishing and Polishing on Roughness and Gloss of Lithium Disilicate and Lithium Silicate Zirconia Reinforced Glass Ceramic for CAD/CAM Systems.

PubMed

Vichi, A; Fonzar, R Fabian; Goracci, C; Carrabba, M; Ferrari, M

To assess the efficacy of dedicated finishing/polishing systems on roughness and gloss of VITA Suprinity and IPS e.max CAD. A total of 24 blocks of Suprinity and 24 of e.max were cut into a wedge shape using an InLab MC-XL milling unit. After crystallization, the 24 Suprinity wedges were divided into four subgroups: group A.1: Suprinity Polishing Set Clinical used for 30 seconds and group A.2: for 60 seconds; group A.3: VITA Akzent Plus Paste; and group A.4: spray. The 24 e.max wedges (group B) were divided into four subgroups according to the finishing procedure: group B.1: Optrafine Ceramic Polishing System for 30 seconds and group B.2: for 60 seconds; group B.3: IPS e.max CAD Crystall/Glaze paste; and group B.4: spray. After finishing/polishing, gloss was assessed with a glossmeter and roughness evaluated with a profilometer. Results were analyzed by applying a two-way analysis of variance for gloss and another for roughness (α=0.05). One specimen per each subgroup was observed with a scanning electron microscope. For roughness, materials and surface were significant factors ( p<0.001). Suprinity exhibited significantly lower roughness than e.max. Also the Material-Surface Treatment interaction was statistically significant ( p=0.026). For gloss, both material and surface treatment were significant factors ( p<0.001). VITA Suprinity showed significantly higher gloss than e.max. Also the Material-Surface Treatment interaction was statistically significant ( p<0.001). Manual finishing/polishing for 60 seconds and glazing paste are the most effective procedures in lowering the roughness of CAD/CAM silica-based glass ceramics. Manual finishing/polishing for 60 seconds allows milled silica-based glass ceramics to yield a higher gloss. VITA Suprinity displayed higher polishability than IPS e.max CAD.

Evaluation of marginal fit of 2 CAD-CAM anatomic contour zirconia crown systems and lithium disilicate glass-ceramic crown.

PubMed

Ji, Min-Kyung; Park, Ji-Hee; Park, Sang-Won; Yun, Kwi-Dug; Oh, Gye-Jeong; Lim, Hyun-Pil

2015-08-01

This study was to evaluate the marginal fit of two CAD-CAM anatomic contour zirconia crown systems compared to lithium disilicate glass-ceramic crowns. Shoulder and deep chamfer margin were formed on each acrylic resin tooth model of a maxillary first premolar. Two CAD-CAM systems (Prettau®Zirconia and ZENOSTAR®ZR translucent) and lithium disilicate glass ceramic (IPS e.max®press) crowns were made (n=16). Each crown was bonded to stone dies with resin cement (Rely X Unicem). Marginal gap and absolute marginal discrepancy of crowns were measured using a light microscope equipped with a digital camera (Leica DFC295) magnified by a factor of 100. Two-way analysis of variance (ANOVA) and post-hoc Tukey's HSD test were conducted to analyze the significance of crown marginal fit regarding the finish line configuration and the fabrication system. The mean marginal gap of lithium disilicate glass ceramic crowns (IPS e.max®press) was significantly lower than that of the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) (P<.05). Both fabrication systems and finish line configurations significantly influenced the absolute marginal discrepancy (P<.05). The lithium disilicate glass ceramic crown (IPS e.max®press) had significantly smaller marginal gap than the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia). In terms of absolute marginal discrepancy, the CAD-CAM anatomic contour zirconia crown system (ZENOSTAR®ZR translucent) had under-extended margin, whereas the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) and lithium disilicate glass ceramic crowns (IPS e.max®press) had overextended margins.

Identification of Cadherin 11 as a Mediator of Dermal Fibrosis and Possible Role in Systemic Sclerosis

PubMed Central

Wu, Minghua; Pedroza, Mesias; Lafyatis, Robert; George, Anuh-Teresa; Mayes, Maureen D.; Assassi, Shervin; Tan, Filemon K.; Brenner, Michael B.; Agarwal, Sandeep K.

2014-01-01

Objective Systemic sclerosis (SSc) is a chronic autoimmune disease clinically manifesting as progressive fibrosis of the skin and internal organs. Recent microarray studies demonstrated that cadherin 11 (Cad-11) expression is increased in the affected skin of patients with SSc. The purpose of this study was to examine our hypothesis that Cad-11 is a mediator of dermal fibrosis. Methods Biopsy samples of skin from SSc patients and healthy control subjects were used for real-time quantitative polymerase chain reaction analysis to assess Cad-11 expression and for immunohistochemistry to determine the expression pattern of Cad-11. To determine whether Cad-11 is a mediator of dermal fibrosis, Cad-11–deficient mice and anti–Cad-11 monoclonal antibodies (mAb) were used in the bleomycin-induced dermal fibrosis model. In vitro studies with dermal fibroblasts and bone marrow–derived macrophages were used to determine the mechanisms by which Cad-11 contributes to the development of tissue fibrosis. Results Levels of messenger RNA for Cad-11 were increased in skin biopsy samples from patients with SSc and correlated with the modified Rodnan skin thickness scores. Cad-11 expression was localized to dermal fibroblasts and macrophages in SSc skin. Cad-11–knockout mice injected with bleomycin had markedly attenuated dermal fibrosis, as quantified by measurements of skin thickness, collagen levels, myofibroblast accumulation, and profibrotic gene expression, in lesional skin as compared to the skin of wild-type mice. In addition, anti–Cad-11 mAb decreased fibrosis at various time points in the bleomycin-induced dermal fibrosis model. In vitro studies demonstrated that Cad-11 regulated the production of transforming growth factor β (TGFβ) by macrophages and the migration of fibroblasts. Conclusion These data demonstrate that Cad-11 is a mediator of dermal fibrosis and TGFβ production and suggest that Cad-11 may be a therapeutic target in SSc. PMID:24757152

Orion Active Thermal Control System Dynamic Modeling Using Simulink/MATLAB

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen J.; Yuko, James

2010-01-01

This paper presents dynamic modeling of the crew exploration vehicle (Orion) active thermal control system (ATCS) using Simulink (Simulink, developed by The MathWorks). The model includes major components in ATCS, such as heat exchangers and radiator panels. The mathematical models of the heat exchanger and radiator are described first. Four different orbits were used to validate the radiator model. The current model results were compared with an independent Thermal Desktop (TD) (Thermal Desktop, PC/CAD-based thermal model builder, developed in Cullimore & Ring (C&R) Technologies) model results and showed good agreement for all orbits. In addition, the Orion ATCS performance was presented for three orbits and the current model results were compared with three sets of solutions- FloCAD (FloCAD, PC/CAD-based thermal/fluid model builder, developed in C&R Technologies) model results, SINDA/FLUINT (SINDA/FLUINT, a generalized thermal/fluid network-style solver ) model results, and independent Simulink model results. For each case, the fluid temperatures at every component on both the crew module and service module sides were plotted and compared. The overall agreement is reasonable for all orbits, with similar behavior and trends for the system. Some discrepancies exist because the control algorithm might vary from model to model. Finally, the ATCS performance for a 45-hr nominal mission timeline was simulated to demonstrate the capability of the model. The results show that the ATCS performs as expected and approximately 2.3 lb water was consumed in the sublimator within the 45 hr timeline before Orion docked at the International Space Station.

Hormone replacement therapy in women with systemic lupus erythematosus and risk of cardiovascular disease.

PubMed

Hochman, J; Urowitz, M B; Ibañez, D; Gladman, D D

2009-04-01

We sought to determine the impact of hormone replacement therapy (HRT) on the occurrence of coronary artery disease (CAD) in women with systemic lupus erythematosus (SLE). Women in the University of Toronto lupus database who had taken HRT with no history of CAD were compared with all post-menopausal female patients with no history of HRT or CAD. Chi-squared and t-tests were used to compare the risk factors of CAD and Kaplan-Meier curve, log rank test and proportional hazard model with time-dependent covariates were used to compare the time from entry into the clinic to occurrence of CAD. A total of 114 HRT-user patients with no history of CAD were compared with 227 post-menopausal non-HRT user SLE controls. The groups were similar with respect to lupus anticoagulant, antiphospholipid antibody, cumulative steroid dose and classic cardiac risk factors. A similar percentage of patients developed CAD in the control (13.7%) and HRT (11.4%) groups. There was no difference in the time to development of CAD. In the multivariate analysis, HRT was not a risk factor for CAD. Only age (P = 0.0001, HR = 1.11, 95% CI = 1.05, 1.17) and SLEDAI-2K (P = 0.0001, HR = 1.10, 95% CI = 1.05, 1.16) were significantly associated with the risk of CAD. In this small group of patients with SLE, HRT alone did not appear to predispose to CAD.

IGES, a key interface specification for CAD/CAM systems integration

NASA Technical Reports Server (NTRS)

Smith, B. M.; Wellington, J.

1984-01-01

The Initial Graphics Exchange Specification (IGES) program has focused the efforts of 52 companies on the development and documentation of a means of graphics data base exchange among present day CAD/CAM systems. The project's brief history has seen the evolution of the Specification into preliminary industrial usage marked by public demonstrations of vendor capability, mandatory requests in procurement actions, and a formalization into an American National Standard in September 1981. Recent events have demonstrated intersystem data exchange among seven vendor systems with a total of 30 vendors committing to offer IGES capability. A full range of documentation supports the IGES project and the recently approved IGES Version 2.0 of the Specification.

Off-line programming motion and process commands for robotic welding of Space Shuttle main engines

NASA Technical Reports Server (NTRS)

Ruokangas, C. C.; Guthmiller, W. A.; Pierson, B. L.; Sliwinski, K. E.; Lee, J. M. F.

1987-01-01

The off-line-programming software and hardware being developed for robotic welding of the Space Shuttle main engine are described and illustrated with diagrams, drawings, graphs, and photographs. The menu-driven workstation-based interactive programming system is designed to permit generation of both motion and process commands for the robotic workcell by weld engineers (with only limited knowledge of programming or CAD systems) on the production floor. Consideration is given to the user interface, geometric-sources interfaces, overall menu structure, weld-parameter data base, and displays of run time and archived data. Ongoing efforts to address limitations related to automatic-downhand-configuration coordinated motion, a lack of source codes for the motion-control software, CAD data incompatibility, interfacing with the robotic workcell, and definition of the welding data base are discussed.

An adaptive incremental approach to constructing ensemble classifiers: Application in an information-theoretic computer-aided decision system for detection of masses in mammograms

PubMed Central

Mazurowski, Maciej A.; Zurada, Jacek M.; Tourassi, Georgia D.

2009-01-01

Ensemble classifiers have been shown efficient in multiple applications. In this article, the authors explore the effectiveness of ensemble classifiers in a case-based computer-aided diagnosis system for detection of masses in mammograms. They evaluate two general ways of constructing subclassifiers by resampling of the available development dataset: Random division and random selection. Furthermore, they discuss the problem of selecting the ensemble size and propose two adaptive incremental techniques that automatically select the size for the problem at hand. All the techniques are evaluated with respect to a previously proposed information-theoretic CAD system (IT-CAD). The experimental results show that the examined ensemble techniques provide a statistically significant improvement (AUC=0.905±0.024) in performance as compared to the original IT-CAD system (AUC=0.865±0.029). Some of the techniques allow for a notable reduction in the total number of examples stored in the case base (to 1.3% of the original size), which, in turn, results in lower storage requirements and a shorter response time of the system. Among the methods examined in this article, the two proposed adaptive techniques are by far the most effective for this purpose. Furthermore, the authors provide some discussion and guidance for choosing the ensemble parameters. PMID:19673196

Computer aided diagnosis system for the Alzheimer's disease based on partial least squares and random forest SPECT image classification.

PubMed

Ramírez, J; Górriz, J M; Segovia, F; Chaves, R; Salas-Gonzalez, D; López, M; Alvarez, I; Padilla, P

2010-03-19

This letter shows a computer aided diagnosis (CAD) technique for the early detection of the Alzheimer's disease (AD) by means of single photon emission computed tomography (SPECT) image classification. The proposed method is based on partial least squares (PLS) regression model and a random forest (RF) predictor. The challenge of the curse of dimensionality is addressed by reducing the large dimensionality of the input data by downscaling the SPECT images and extracting score features using PLS. A RF predictor then forms an ensemble of classification and regression tree (CART)-like classifiers being its output determined by a majority vote of the trees in the forest. A baseline principal component analysis (PCA) system is also developed for reference. The experimental results show that the combined PLS-RF system yields a generalization error that converges to a limit when increasing the number of trees in the forest. Thus, the generalization error is reduced when using PLS and depends on the strength of the individual trees in the forest and the correlation between them. Moreover, PLS feature extraction is found to be more effective for extracting discriminative information from the data than PCA yielding peak sensitivity, specificity and accuracy values of 100%, 92.7%, and 96.9%, respectively. Moreover, the proposed CAD system outperformed several other recently developed AD CAD systems. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

Black box integration of computer-aided diagnosis into PACS deserves a second chance: results of a usability study concerning bone age assessment.

PubMed

Geldermann, Ina; Grouls, Christoph; Kuhl, Christiane; Deserno, Thomas M; Spreckelsen, Cord

2013-08-01

Usability aspects of different integration concepts for picture archiving and communication systems (PACS) and computer-aided diagnosis (CAD) were inquired on the example of BoneXpert, a program determining the skeletal age from a left hand's radiograph. CAD-PACS integration was assessed according to its levels: data, function, presentation, and context integration focusing on usability aspects. A user-based study design was selected. Statements of seven experienced radiologists using two alternative types of integration provided by BoneXpert were acquired and analyzed using a mixed-methods approach based on think-aloud records and a questionnaire. In both variants, the CAD module (BoneXpert) was easily integrated in the workflow, found comprehensible and fitting in the conceptual framework of the radiologists. Weak points of the software integration referred to data and context integration. Surprisingly, visualization of intermediate image processing states (presentation integration) was found less important as compared to efficient handling and fast computation. Seamlessly integrating CAD into the PACS without additional work steps or unnecessary interrupts and without visualizing intermediate images may considerably improve software performance and user acceptance with efforts in time.

Enforcing compatibility and constraint conditions and information retrieval at the design action

NASA Technical Reports Server (NTRS)

Woodruff, George W.

1990-01-01

The design of complex entities is a multidisciplinary process involving several interacting groups and disciplines. There is a need to integrate the data in such environments to enhance the collaboration between these groups and to enforce compatibility between dependent data entities. This paper discusses the implementation of a workstation based CAD system that is integrated with a DBMS and an expert system, CLIPS, (both implemented on a mini computer) to provide such collaborative and compatibility enforcement capabilities. The current implementation allows for a three way link between the CAD system, the DBMS and CLIPS. The engineering design process associated with the design and fabrication of sheet metal housing for computers in a large computer manufacturing facility provides the basis for this prototype system.

An Integrated Unix-based CAD System for the Design and Testing of Custom VLSI Chips

NASA Technical Reports Server (NTRS)

Deutsch, L. J.

1985-01-01

A computer aided design (CAD) system that is being used at the Jet Propulsion Laboratory for the design of custom and semicustom very large scale integrated (VLSI) chips is described. The system consists of a Digital Equipment Corporation VAX computer with the UNIX operating system and a collection of software tools for the layout, simulation, and verification of microcircuits. Most of these tools were written by the academic community and are, therefore, available to JPL at little or no cost. Some small pieces of software have been written in-house in order to make all the tools interact with each other with a minimal amount of effort on the part of the designer.

Molecular cloning and functional analysis of nine cinnamyl alcohol dehydrogenase family members in Populus tomentosa.

PubMed

Chao, Nan; Liu, Shu-Xin; Liu, Bing-Mei; Li, Ning; Jiang, Xiang-Ning; Gai, Ying

2014-11-01

Nine CAD/CAD-like genes in P. tomentosa were classified into four classes based on expression patterns, phylogenetic analysis and biochemical properties with modification for the previous claim of SAD. Cinnamyl alcohol dehydrogenase (CAD) functions in monolignol biosynthesis and plays a critical role in wood development and defense. In this study, we isolated and cloned nine CAD/CAD-like genes in the Populus tomentosa genome. We investigated differential expression using microarray chips and found that PtoCAD1 was highly expressed in bud, root and vascular tissues (xylem and phloem) with the greatest expression in the root. Differential expression in tissues was demonstrated for PtoCAD3, PtoCAD6 and PtoCAD9. Biochemical analysis of purified PtoCADs in vitro indicated PtoCAD1, PtoCAD2 and PtoCAD8 had detectable activity against both coniferaldehyde and sinapaldehyde. PtoCAD1 used both substrates with high efficiency. PtoCAD2 showed no specific requirement for sinapaldehyde in spite of its high identity with so-called PtrSAD (sinapyl alcohol dehydrogenase). In addition, the enzymatic activity of PtoCAD1 and PtoCAD2 was affected by temperature. We classified these nine CAD/CAD-like genes into four classes: class I included PtoCAD1, which was a bone fide CAD with the highest activity; class II included PtoCAD2, -5, -7, -8, which might function in monolignol biosynthesis and defense; class III genes included PtoCAD3, -6, -9, which have a distinct expression pattern; class IV included PtoCAD12, which has a distinct structure. These data suggest divergence of the PtoCADs and its homologs, related to their functions. We propose genes in class II are a subset of CAD genes that evolved before angiosperms appeared. These results suggest CAD/CAD-like genes in classes I and II play a role in monolignol biosynthesis and contribute to our knowledge of lignin biosynthesis in P. tomentosa.

A Computer-Aided Diagnosis System Using Artificial Intelligence for the Diagnosis and Characterization of Thyroid Nodules on Ultrasound: Initial Clinical Assessment.

PubMed

Choi, Young Jun; Baek, Jung Hwan; Park, Hye Sun; Shim, Woo Hyun; Kim, Tae Yong; Shong, Young Kee; Lee, Jeong Hyun

2017-04-01

An initial clinical assessment is described of a new, commercially available, computer-aided diagnosis (CAD) system using artificial intelligence (AI) for thyroid ultrasound, and its performance is evaluated in the diagnosis of malignant thyroid nodules and categorization of nodule characteristics. Patients with thyroid nodules with decisive diagnosis, whether benign or malignant, were consecutively enrolled from November 2015 to February 2016. An experienced radiologist reviewed the ultrasound image characteristics of the thyroid nodules, while another radiologist assessed the same thyroid nodules using the CAD system, providing ultrasound characteristics and a diagnosis of whether nodules were benign or malignant. The diagnostic performance and agreement of US characteristics between the experienced radiologist and the CAD system were compared. In total, 102 thyroid nodules from 89 patients were included; 59 (57.8%) were benign and 43 (42.2%) were malignant. The CAD system showed a similar sensitivity as the experienced radiologist (90.7% vs. 88.4%, p > 0.99), but a lower specificity and a lower area under the receiver operating characteristic (AUROC) curve (specificity: 74.6% vs. 94.9%, p = 0.002; AUROC: 0.83 vs. 0.92, p = 0.021). Classifications of the ultrasound characteristics (composition, orientation, echogenicity, and spongiform) between radiologist and CAD system were in substantial agreement (κ = 0.659, 0.740, 0.733, and 0.658, respectively), while the margin showed a fair agreement (κ = 0.239). The sensitivity of the CAD system using AI for malignant thyroid nodules was as good as that of the experienced radiologist, while specificity and accuracy were lower than those of the experienced radiologist. The CAD system showed an acceptable agreement with the experienced radiologist for characterization of thyroid nodules.

Epistatic interaction between haplotypes of the ghrelin ligand and receptor genes influence susceptibility to myocardial infarction and coronary artery disease.

PubMed

Baessler, Andrea; Fischer, Marcus; Mayer, Bjoern; Koehler, Martina; Wiedmann, Silke; Stark, Klaus; Doering, Angela; Erdmann, Jeanette; Riegger, Guenter; Schunkert, Heribert; Kwitek, Anne E; Hengstenberg, Christian

2007-04-15

Data from both experimental models and humans provide evidence that ghrelin and its receptor, the growth hormone secretagogue receptor (ghrelin receptor, GHSR), possess a variety of cardiovascular effects. Thus, we hypothesized that genetic variants within the ghrelin system (ligand ghrelin and its receptor GHSR) are associated with susceptibility to myocardial infarction (MI) and coronary artery disease (CAD). Seven single nucleotide polymorphisms (SNPs) covering the GHSR region as well as eight SNPs across the ghrelin gene (GHRL) region were genotyped in index MI patients (864 Caucasians, 'index MI cases') from the German MI family study and in matched controls without evidence of CAD (864 Caucasians, 'controls', MONICA Augsburg). In addition, siblings of these MI patients with documented severe CAD (826 'affected sibs') were matched likewise with controls (n = 826 Caucasian 'controls') and used for verification. The effect of interactions between genetic variants of both genes of the ghrelin system was explored by conditional classification tree models. We found association of several GHSR SNPs with MI [best SNP odds ratio (OR) 1.7 (1.2-2.5); P = 0.002] using a recessive model. Moreover, we identified a common GHSR haplotype which significantly increases the risk for MI [multivariate adjusted OR for homozygous carriers 1.6 (1.1-2.5) and CAD OR 1.6 (1.1-2.5)]. In contrast, no relationship between genetic variants and the disease could be revealed for GHRL. However, the increase in MI/CAD frequency related to the susceptible GHSR haplotype was abolished when it coincided with a common GHRL haplotype. Multivariate adjustments as well as permutation-based methods conveyed the same results. These data are the first to demonstrate an association of SNPs and haplotypes within important genes of the ghrelin system and the susceptibility to MI, whereas association with MI/CAD could be identified for genetic variants across GHSR, no relationship could be revealed for GHRL itself. However, we found an effect of GHRL dependent upon the presence of a common, MI and CAD susceptible haplotype of GHSR. Thus, our data suggest that specific haplotypes of the ghrelin ligand and its receptor act epistatically to affect susceptibility or tolerance to MI and/or CAD.

IFEMS, an Interactive Finite Element Modeling System Using a CAD/CAM System

NASA Technical Reports Server (NTRS)

Mckellip, S.; Schuman, T.; Lauer, S.

1980-01-01

A method of coupling a CAD/CAM system with a general purpose finite element mesh generator is described. The three computer programs which make up the interactive finite element graphics system are discussed.

Version control system of CAD documents and PLC projects

NASA Astrophysics Data System (ADS)

Khudyakov, P. Yu; Kisel’nikov, A. Yu; Startcev, I. M.; Kovalev, A. A.

2018-05-01

The paper presents the process of developing a version control system for CAD documents and PLC projects. The software was tested and the optimal composition of the modules was selected. The introduction of the system has made it possible to increase the safety and stability of the process control systems, as well as to reduce the number of conflicts for versions of CAD files. The number of incidents at the enterprise related to the use of incorrect versions of PLC projects is reduced to 0.

Cool-and Unusual-CAD Applications

ERIC Educational Resources Information Center

Calhoun, Ken

2004-01-01

This article describes several very useful applications of AutoCAD that may lie outside the normal scope of application. AutoCAD commands used in this article are based on AutoCAD 2000I. The author and his students used a Hewlett Packard 750C DesignJet plotter for plotting. (Contains 5 figures and 5 photos.)

A new Fourier transform based CBIR scheme for mammographic mass classification: a preliminary invariance assessment

NASA Astrophysics Data System (ADS)

Gundreddy, Rohith Reddy; Tan, Maxine; Qui, Yuchen; Zheng, Bin

2015-03-01

The purpose of this study is to develop and test a new content-based image retrieval (CBIR) scheme that enables to achieve higher reproducibility when it is implemented in an interactive computer-aided diagnosis (CAD) system without significantly reducing lesion classification performance. This is a new Fourier transform based CBIR algorithm that determines image similarity of two regions of interest (ROI) based on the difference of average regional image pixel value distribution in two Fourier transform mapped images under comparison. A reference image database involving 227 ROIs depicting the verified soft-tissue breast lesions was used. For each testing ROI, the queried lesion center was systematically shifted from 10 to 50 pixels to simulate inter-user variation of querying suspicious lesion center when using an interactive CAD system. The lesion classification performance and reproducibility as the queried lesion center shift were assessed and compared among the three CBIR schemes based on Fourier transform, mutual information and Pearson correlation. Each CBIR scheme retrieved 10 most similar reference ROIs and computed a likelihood score of the queried ROI depicting a malignant lesion. The experimental results shown that three CBIR schemes yielded very comparable lesion classification performance as measured by the areas under ROC curves with the p-value greater than 0.498. However, the CBIR scheme using Fourier transform yielded the highest invariance to both queried lesion center shift and lesion size change. This study demonstrated the feasibility of improving robustness of the interactive CAD systems by adding a new Fourier transform based image feature to CBIR schemes.

Writing DNA with GenoCAD.

PubMed

Czar, Michael J; Cai, Yizhi; Peccoud, Jean

2009-07-01

Chemical synthesis of custom DNA made to order calls for software streamlining the design of synthetic DNA sequences. GenoCAD (www.genocad.org) is a free web-based application to design protein expression vectors, artificial gene networks and other genetic constructs composed of multiple functional blocks called genetic parts. By capturing design strategies in grammatical models of DNA sequences, GenoCAD guides the user through the design process. By successively clicking on icons representing structural features or actual genetic parts, complex constructs composed of dozens of functional blocks can be designed in a matter of minutes. GenoCAD automatically derives the construct sequence from its comprehensive libraries of genetic parts. Upon completion of the design process, users can download the sequence for synthesis or further analysis. Users who elect to create a personal account on the system can customize their workspace by creating their own parts libraries, adding new parts to the libraries, or reusing designs to quickly generate sets of related constructs.

RESEARCH AND DESIGN ABOUT VERSATILE 3D-CAD ENGINE FOR CONSTRUCTION

NASA Astrophysics Data System (ADS)

Tanaka, Shigenori; Kubota, Satoshi; Kitagawa, Etsuji; Monobe, Kantaro; Nakamura, Kenji

In the construction field of Japan, it is an important subject to build the environment where 3D-CAD data is used for CALS/EC, information construction, and an improvement in productivity. However, in the construction field, 3D-CAD software does not exist under the present circumstances. Then, in order to support development of domestic 3D-CAD software, it is required to develop a 3D-CAD engine. In this research, in order to familiarize the 3D-CAD software at low cost and quickly and build the environment where the 3D-CAD software is utilizable, investigation for designing a 3D-CAD engine is proposed. The target for investigation are the use scene of 3D-CAD, the seeds which accompany 3D-CAD, a standardization trend, existing products, IT component engineering. Based on results of the investigation, the functional requirements for the 3D-CAD engine for the construction field were concluded.

Information fusion for diabetic retinopathy CAD in digital color fundus photographs.

PubMed

Niemeijer, Meindert; Abramoff, Michael D; van Ginneken, Bram

2009-05-01

The purpose of computer-aided detection or diagnosis (CAD) technology has so far been to serve as a second reader. If, however, all relevant lesions in an image can be detected by CAD algorithms, use of CAD for automatic reading or prescreening may become feasible. This work addresses the question how to fuse information from multiple CAD algorithms, operating on multiple images that comprise an exam, to determine a likelihood that the exam is normal and would not require further inspection by human operators. We focus on retinal image screening for diabetic retinopathy, a common complication of diabetes. Current CAD systems are not designed to automatically evaluate complete exams consisting of multiple images for which several detection algorithm output sets are available. Information fusion will potentially play a crucial role in enabling the application of CAD technology to the automatic screening problem. Several different fusion methods are proposed and their effect on the performance of a complete comprehensive automatic diabetic retinopathy screening system is evaluated. Experiments show that the choice of fusion method can have a large impact on system performance. The complete system was evaluated on a set of 15,000 exams (60,000 images). The best performing fusion method obtained an area under the receiver operator characteristic curve of 0.881. This indicates that automated prescreening could be applied in diabetic retinopathy screening programs.

CAD/CAM approach to improving industry productivity gathers momentum

NASA Technical Reports Server (NTRS)

Fulton, R. E.

1982-01-01

Recent results and planning for the NASA/industry Integrated Programs for Aerospace-Vehicle Design (IPAD) program for improving productivity with CAD/CAM methods are outlined. The industrial group work is being mainly done by Boeing, and progress has been made in defining the designer work environment, developing requirements and a preliminary design for a future CAD/CAM system, and developing CAD/CAM technology. The work environment was defined by conducting a detailed study of a reference design process, and key software elements for a CAD/CAM system have been defined, specifically for interactive design or experiment control processes. Further work is proceeding on executive, data management, geometry and graphics, and general utility software, and dynamic aspects of the programs being developed are outlined

Quality assurance and training procedures for computer-aided detection and diagnosis systems in clinical usea)

PubMed Central

Huo, Zhimin; Summers, Ronald M.; Paquerault, Sophie; Lo, Joseph; Hoffmeister, Jeffrey; Armato, Samuel G.; Freedman, Matthew T.; Lin, Jesse; Ben Lo, Shih-Chung; Petrick, Nicholas; Sahiner, Berkman; Fryd, David; Yoshida, Hiroyuki; Chan, Heang-Ping

2013-01-01

Computer-aided detection/diagnosis (CAD) is increasingly used for decision support by clinicians for detection and interpretation of diseases. However, there are no quality assurance (QA) requirements for CAD in clinical use at present. QA of CAD is important so that end users can be made aware of changes in CAD performance both due to intentional or unintentional causes. In addition, end-user training is critical to prevent improper use of CAD, which could potentially result in lower overall clinical performance. Research on QA of CAD and user training are limited to date. The purpose of this paper is to bring attention to these issues, inform the readers of the opinions of the members of the American Association of Physicists in Medicine (AAPM) CAD subcommittee, and thus stimulate further discussion in the CAD community on these topics. The recommendations in this paper are intended to be work items for AAPM task groups that will be formed to address QA and user training issues on CAD in the future. The work items may serve as a framework for the discussion and eventual design of detailed QA and training procedures for physicists and users of CAD. Some of the recommendations are considered by the subcommittee to be reasonably easy and practical and can be implemented immediately by the end users; others are considered to be “best practice” approaches, which may require significant effort, additional tools, and proper training to implement. The eventual standardization of the requirements of QA procedures for CAD will have to be determined through consensus from members of the CAD community, and user training may require support of professional societies. It is expected that high-quality CAD and proper use of CAD could allow these systems to achieve their true potential, thus benefiting both the patients and the clinicians, and may bring about more widespread clinical use of CAD for many other diseases and applications. It is hoped that the awareness of the need for appropriate CAD QA and user training will stimulate new ideas and approaches for implementing such procedures efficiently and effectively as well as funding opportunities to fulfill such critical efforts. PMID:23822459

Clinical experience with a computer-aided diagnosis system for automatic detection of pulmonary nodules at spiral CT of the chest

NASA Astrophysics Data System (ADS)

Wormanns, Dag; Fiebich, Martin; Saidi, Mustafa; Diederich, Stefan; Heindel, Walter

2001-05-01

The purpose of the study was to evaluate a computer aided diagnosis (CAD) workstation with automatic detection of pulmonary nodules at low-dose spiral CT in a clinical setting for early detection of lung cancer. Two radiologists in consensus reported 88 consecutive spiral CT examinations. All examinations were reviewed using a UNIX-based CAD workstation with a self-developed algorithm for automatic detection of pulmonary nodules. The algorithm was designed to detect nodules with at least 5 mm diameter. The results of automatic nodule detection were compared to the consensus reporting of two radiologists as gold standard. Additional CAD findings were regarded as nodules initially missed by the radiologists or as false positive results. A total of 153 nodules were detected with all modalities (diameter: 85 nodules <5mm, 63 nodules 5-9 mm, 5 nodules >= 10 mm). Reasons for failure of automatic nodule detection were assessed. Sensitivity of radiologists for nodules >=5 mm was 85%, sensitivity of CAD was 38%. For nodules >=5 mm without pleural contact sensitivity was 84% for radiologists at 45% for CAD. CAD detected 15 (10%) nodules not mentioned in the radiologist's report but representing real nodules, among them 10 (15%) nodules with a diameter $GREW5 mm. Reasons for nodules missed by CAD include: exclusion because of morphological features during region analysis (33%), nodule density below the detection threshold (26%), pleural contact (33%), segmentation errors (5%) and other reasons (2%). CAD improves detection of pulmonary nodules at spiral CT significantly and is a valuable second opinion in a clinical setting for lung cancer screening. Optimization of region analysis and an appropriate density threshold have a potential for further improvement of automatic nodule detection.

Cost-effectiveness of filgrastim and pegfilgrastim as primary prophylaxis against febrile neutropenia in lymphoma patients.

PubMed

Lathia, Nina; Isogai, Pierre K; De Angelis, Carlo; Smith, Thomas J; Cheung, Matthew; Mittmann, Nicole; Hoch, Jeffrey S; Walker, Scott

2013-08-07

Febrile neutropenia is a serious toxicity of cancer chemotherapy that is usually treated in hospital. We assessed the cost-effectiveness of filgrastim and pegfilgrastim as primary prophylaxis against febrile neutropenia in diffuse large B-cell lymphoma (DLBCL) patients undergoing chemotherapy. We used a Markov model that followed patients through induction chemotherapy to compare the three prophylaxis strategies: 1) no primary prophylaxis against febrile neutropenia; 2) primary prophylaxis with 10 days of filgrastim therapy; and 3) primary prophylaxis with a single dose of pegfilgrastim. The target population was a hypothetical cohort of 64-year-old men and women with DLBCL. Data sources included published literature and current clinical practice. The analysis was conducted from a publicly funded health-care system perspective. The main outcome measures included costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs). In the base-case analysis, costs associated with no primary prophylaxis, primary prophylaxis with 10 days of filgrastim, and primary prophylaxis with pegfilgrastim were CaD $7314, CaD $13947, and CaD $16290, respectively. The QALYs associated with the three strategies were 0.2004, 0.2015, and 0.2024, respectively. The ICER for the filgrastim vs no primary prophylaxis strategy was CaD $5796000 per QALY. The ICER for the pegfilgrastim vs filgrastim primary prophylaxis strategy was CaD $2611000 per QALY. All one-way sensitivity analyses yielded ICERs greater than CaD $400000 per QALY. Cost-effectiveness acceptability curves show that 20.0% of iterations are cost-effective at a willingness-to-pay threshold of CaD $1595000 for the filgrastim strategy and CaD $561000 for the pegfilgrastim strategy. Primary prophylaxis against febrile neutropenia with either filgrastim or pegfilgrastim is not cost-effective in DLBCL patients.

A Comparison of the Marginal and Internal Fit of Cobalt- Chromium Copings Fabricated by Two Different CAD/CAM Systems (CAD/ Milling, CAD/ Ceramill Sintron).

PubMed

Vojdani, Mahroo; Torabi, Kianoosh; Atashkar, Berivan; Heidari, Hossein; Torabi Ardakani, Mahshid

2016-12-01

Marginal fitness is the most important criteria for evaluation of the clinical acceptability of a cast restoration. Marginal gap which is due to cement solubility and plaque retention is potentially detrimental to both tooth and periodontal tissues. This in vitro study aimed to evaluate the marginal and internal fit of cobalt- chromium (Co-Cr) copings fabricated by two different CAD/CAM systems: (CAD/ milling and CAD/ Ceramill Sintron). We prepared one machined standard stainless steel master model with following dimensions: 7 mm height, 5mm diameter, 90˚ shoulder marginal finish line with 1 mm width, 10˚ convergence angle and anti-rotational surface on the buccal aspect of the die. There were 10 copings produced from hard presintered Co-Cr blocks according to CAD/ Milling technique and ten copings from soft non- presintered Co-Cr blocks according to CAD/ Ceramill Sintron technique. Marginal and internal accuracies of copings were documented by the replica technique. Replicas were examined at ten reference points under a digital microscope (230X). The Student's t-test was used for statistical analysis. p < 0.001 was considered significant. Statistically significant differences existed between the groups ( p < 0.001). The CAD/milling group (hard copings) had a mean marginal discrepancy (MD) of 104 µm, axial discrepancy (AD) of 23 µm and occlusal discrepancy of 130 µm. For CAD/ Ceramill Sintron group, these values were 195 µm (MD), 46 µm (AD), and 232 µm (OD). Internal total discrepancy (ITD) for the CAD/milling group was 77 µm, whereas for the CAD/Ceramill Sintron group was 143 µm. Hard presintered Co-Cr copings had significantly higher marginal and internal accuracies compared to the soft non-presintered copings.

The efficacy of using computer-aided detection (CAD) for detection of breast cancer in mammography screening: a systematic review.

PubMed

Henriksen, Emilie L; Carlsen, Jonathan F; Vejborg, Ilse Mm; Nielsen, Michael B; Lauridsen, Carsten A

2018-01-01

Background Early detection of breast cancer (BC) is crucial in lowering the mortality. Purpose To present an overview of studies concerning computer-aided detection (CAD) in screening mammography for early detection of BC and compare diagnostic accuracy and recall rates (RR) of single reading (SR) with SR + CAD and double reading (DR) with SR + CAD. Material and Methods PRISMA guidelines were used as a review protocol. Articles on clinical trials concerning CAD for detection of BC in a screening population were included. The literature search resulted in 1522 records. A total of 1491 records were excluded by abstract and 18 were excluded by full text reading. A total of 13 articles were included. Results All but two studies from the SR vs. SR + CAD group showed an increased sensitivity and/or cancer detection rate (CDR) when adding CAD. The DR vs. SR + CAD group showed no significant differences in sensitivity and CDR. Adding CAD to SR increased the RR and decreased the specificity in all but one study. For the DR vs. SR + CAD group only one study reported a significant difference in RR. Conclusion All but two studies showed an increase in RR, sensitivity and CDR when adding CAD to SR. Compared to DR no statistically significant differences in sensitivity or CDR were reported. Additional studies based on organized population-based screening programs, with longer follow-up time, high-volume readers, and digital mammography are needed to evaluate the efficacy of CAD.

Content-Based Image Retrieval System for Pulmonary Nodules: Assisting Radiologists in Self-Learning and Diagnosis of Lung Cancer.

PubMed

Dhara, Ashis Kumar; Mukhopadhyay, Sudipta; Dutta, Anirvan; Garg, Mandeep; Khandelwal, Niranjan

2017-02-01

Visual information of similar nodules could assist the budding radiologists in self-learning. This paper presents a content-based image retrieval (CBIR) system for pulmonary nodules, observed in lung CT images. The reported CBIR systems of pulmonary nodules cannot be put into practice as radiologists need to draw the boundary of nodules during query formation and feature database creation. In the proposed retrieval system, the pulmonary nodules are segmented using a semi-automated technique, which requires a seed point on the nodule from the end-user. The involvement of radiologists in feature database creation is also reduced, as only a seed point is expected from radiologists instead of manual delineation of the boundary of the nodules. The performance of the retrieval system depends on the accuracy of the segmentation technique. Several 3D features are explored to improve the performance of the proposed retrieval system. A set of relevant shape and texture features are considered for efficient representation of the nodules in the feature space. The proposed CBIR system is evaluated for three configurations such as configuration-1 (composite rank of malignancy "1","2" as benign and "4","5" as malignant), configuration-2 (composite rank of malignancy "1","2", "3" as benign and "4","5" as malignant), and configuration-3 (composite rank of malignancy "1","2" as benign and "3","4","5" as malignant). Considering top 5 retrieved nodules and Euclidean distance metric, the precision achieved by the proposed method for configuration-1, configuration-2, and configuration-3 are 82.14, 75.91, and 74.27 %, respectively. The performance of the proposed CBIR system is close to the most recent technique, which is dependent on radiologists for manual segmentation of nodules. A computer-aided diagnosis (CAD) system is also developed based on CBIR paradigm. Performance of the proposed CBIR-based CAD system is close to performance of the CAD system using support vector machine.

Computer-Aided Diagnosis Systems for Lung Cancer: Challenges and Methodologies

PubMed Central

El-Baz, Ayman; Beache, Garth M.; Gimel'farb, Georgy; Suzuki, Kenji; Okada, Kazunori; Elnakib, Ahmed; Soliman, Ahmed; Abdollahi, Behnoush

2013-01-01

This paper overviews one of the most important, interesting, and challenging problems in oncology, the problem of lung cancer diagnosis. Developing an effective computer-aided diagnosis (CAD) system for lung cancer is of great clinical importance and can increase the patient's chance of survival. For this reason, CAD systems for lung cancer have been investigated in a huge number of research studies. A typical CAD system for lung cancer diagnosis is composed of four main processing steps: segmentation of the lung fields, detection of nodules inside the lung fields, segmentation of the detected nodules, and diagnosis of the nodules as benign or malignant. This paper overviews the current state-of-the-art techniques that have been developed to implement each of these CAD processing steps. For each technique, various aspects of technical issues, implemented methodologies, training and testing databases, and validation methods, as well as achieved performances, are described. In addition, the paper addresses several challenges that researchers face in each implementation step and outlines the strengths and drawbacks of the existing approaches for lung cancer CAD systems. PMID:23431282

DOE Office of Scientific and Technical Information (OSTI.GOV)

Setio, Arnaud A. A., E-mail: arnaud.arindraadiyoso@radboudumc.nl; Jacobs, Colin; Gelderblom, Jaap

Purpose: Current computer-aided detection (CAD) systems for pulmonary nodules in computed tomography (CT) scans have a good performance for relatively small nodules, but often fail to detect the much rarer larger nodules, which are more likely to be cancerous. We present a novel CAD system specifically designed to detect solid nodules larger than 10 mm. Methods: The proposed detection pipeline is initiated by a three-dimensional lung segmentation algorithm optimized to include large nodules attached to the pleural wall via morphological processing. An additional preprocessing is used to mask out structures outside the pleural space to ensure that pleural and parenchymalmore » nodules have a similar appearance. Next, nodule candidates are obtained via a multistage process of thresholding and morphological operations, to detect both larger and smaller candidates. After segmenting each candidate, a set of 24 features based on intensity, shape, blobness, and spatial context are computed. A radial basis support vector machine (SVM) classifier was used to classify nodule candidates, and performance was evaluated using ten-fold cross-validation on the full publicly available lung image database consortium database. Results: The proposed CAD system reaches a sensitivity of 98.3% (234/238) and 94.1% (224/238) large nodules at an average of 4.0 and 1.0 false positives/scan, respectively. Conclusions: The authors conclude that the proposed dedicated CAD system for large pulmonary nodules can identify the vast majority of highly suspicious lesions in thoracic CT scans with a small number of false positives.« less

The evaluation of multi-structure, multi-atlas pelvic anatomy features in a prostate MR lymphography CAD system

NASA Astrophysics Data System (ADS)

Meijs, M.; Debats, O.; Huisman, H.

2015-03-01

In prostate cancer, the detection of metastatic lymph nodes indicates progression from localized disease to metastasized cancer. The detection of positive lymph nodes is, however, a complex and time consuming task for experienced radiologists. Assistance of a two-stage Computer-Aided Detection (CAD) system in MR Lymphography (MRL) is not yet feasible due to the large number of false positives in the first stage of the system. By introducing a multi-structure, multi-atlas segmentation, using an affine transformation followed by a B-spline transformation for registration, the organ location is given by a mean density probability map. The atlas segmentation is semi-automatically drawn with ITK-SNAP, using Active Contour Segmentation. Each anatomic structure is identified by a label number. Registration is performed using Elastix, using Mutual Information and an Adaptive Stochastic Gradient optimization. The dataset consists of the MRL scans of ten patients, with lymph nodes manually annotated in consensus by two expert readers. The feature map of the CAD system consists of the Multi-Atlas and various other features (e.g. Normalized Intensity and multi-scale Blobness). The voxel-based Gentleboost classifier is evaluated using ROC analysis with cross validation. We show in a set of 10 studies that adding multi-structure, multi-atlas anatomical structure likelihood features improves the quality of the lymph node voxel likelihood map. Multiple structure anatomy maps may thus make MRL CAD more feasible.

Multi-site evaluation of a computer aided detection (CAD) algorithm for small acute intra-cranial hemorrhage and development of a stand-alone CAD system ready for deployment in a clinical environment

NASA Astrophysics Data System (ADS)

Deshpande, Ruchi R.; Fernandez, James; Lee, Joon K.; Chan, Tao; Liu, Brent J.; Huang, H. K.

2010-03-01

Timely detection of Acute Intra-cranial Hemorrhage (AIH) in an emergency environment is essential for the triage of patients suffering from Traumatic Brain Injury. Moreover, the small size of lesions and lack of experience on the reader's part could lead to difficulties in the detection of AIH. A CT based CAD algorithm for the detection of AIH has been developed in order to improve upon the current standard of identification and treatment of AIH. A retrospective analysis of the algorithm has already been carried out with 135 AIH CT studies with 135 matched normal head CT studies from the Los Angeles County General Hospital/ University of Southern California Hospital System (LAC/USC). In the next step, AIH studies have been collected from Walter Reed Army Medical Center, and are currently being processed using the AIH CAD system as part of implementing a multi-site assessment and evaluation of the performance of the algorithm. The sensitivity and specificity numbers from the Walter Reed study will be compared with the numbers from the LAC/USC study to determine if there are differences in the presentation and detection due to the difference in the nature of trauma between the two sites. Simultaneously, a stand-alone system with a user friendly GUI has been developed to facilitate implementation in a clinical setting.

A cloud platform for remote diagnosis of breast cancer in mammography by fusion of machine and human intelligence

NASA Astrophysics Data System (ADS)

Jiang, Guodong; Fan, Ming; Li, Lihua

2016-03-01

Mammography is the gold standard for breast cancer screening, reducing mortality by about 30%. The application of a computer-aided detection (CAD) system to assist a single radiologist is important to further improve mammographic sensitivity for breast cancer detection. In this study, a design and realization of the prototype for remote diagnosis system in mammography based on cloud platform were proposed. To build this system, technologies were utilized including medical image information construction, cloud infrastructure and human-machine diagnosis model. Specifically, on one hand, web platform for remote diagnosis was established by J2EE web technology. Moreover, background design was realized through Hadoop open-source framework. On the other hand, storage system was built up with Hadoop distributed file system (HDFS) technology which enables users to easily develop and run on massive data application, and give full play to the advantages of cloud computing which is characterized by high efficiency, scalability and low cost. In addition, the CAD system was realized through MapReduce frame. The diagnosis module in this system implemented the algorithms of fusion of machine and human intelligence. Specifically, we combined results of diagnoses from doctors' experience and traditional CAD by using the man-machine intelligent fusion model based on Alpha-Integration and multi-agent algorithm. Finally, the applications on different levels of this system in the platform were also discussed. This diagnosis system will have great importance for the balanced health resource, lower medical expense and improvement of accuracy of diagnosis in basic medical institutes.

Computer Aided Detection (CAD) Systems for Mammography and the Use of GRID in Medicine

NASA Astrophysics Data System (ADS)

Lauria, Adele

It is well known that the most effective way to defeat breast cancer is early detection, as surgery and medical therapies are more efficient when the disease is diagnosed at an early stage. The principal diagnostic technique for breast cancer detection is X-ray mammography. Screening programs have been introduced in many European countries to invite women to have periodic radiological breast examinations. In such screenings, radiologists are often required to examine large numbers of mammograms with a double reading, that is, two radiologists examine the images independently and then compare their results. In this way an increment in sensitivity (the rate of correctly identified images with a lesion) of up to 15% is obtained.1,2 In most radiological centres, it is a rarity to find two radiologists to examine each report. In recent years different Computer Aided Detection (CAD) systems have been developed as a support to radiologists working in mammography: one may hope that the "second opinion" provided by CAD might represent a lower cost alternative to improve the diagnosis. At present, four CAD systems have obtained the FDA approval in the USA. † Studies3,4 show an increment in sensitivity when CAD systems are used. Freer and Ulissey in 2001 5 demonstrated that the use of a commercial CAD system (ImageChecker M1000, R2 Technology) increases the number of cancers detected up to 19.5% with little increment in recall rate. Ciatto et al.,5 in a study simulating a double reading with a commercial CAD system (SecondLook‡), showed a moderate increment in sensitivity while reducing specificity (the rate of correctly identified images without a lesion). Notwithstanding these optimistic results, there is an ongoing debate to define the advantages of the use of CAD as second reader: the main limits underlined, e.g., by Nishikawa6 are that retrospective studies are considered much too optimistic and that clinical studies must be performed to demonstrate a statistically significant benefit from the use of CAD.

Interpretation Time Using a Concurrent-Read Computer-Aided Detection System for Automated Breast Ultrasound in Breast Cancer Screening of Women With Dense Breast Tissue.

PubMed

Jiang, Yulei; Inciardi, Marc F; Edwards, Alexandra V; Papaioannou, John

2018-05-24

The purpose of this study was to compare diagnostic accuracy and interpretation time of screening automated breast ultrasound (ABUS) for women with dense breast tissue without and with use of a recently U.S. Food and Drug Administration-approved computer-aided detection (CAD) system for concurrent read. In a retrospective observer performance study, 18 radiologists interpreted a cancer-enriched set (i.e., cancer prevalence higher than in the original screening cohort) of 185 screening ABUS studies (52 with and 133 without breast cancer). These studies were from a large cohort of ABUS screened patients interpreted as BI-RADS density C or D. Each reader interpreted each case twice in a counterbalanced study, once without the CAD system and once with it, separated by 4 weeks. For each case, each reader identified abnormal findings and reported BI-RADS assessment category and level of suspicion for breast cancer. Interpretation time was recorded. Level of suspicion data were compared to evaluate diagnostic accuracy by means of the Dorfman-Berbaum-Metz method of jackknife with ANOVA ROC analysis. Interpretation times were compared by ANOVA. The ROC AUC was 0.848 with the CAD system, compared with 0.828 without it, for a difference of 0.020 (95% CI, -0.011 to 0.051) and was statistically noninferior to the AUC without the CAD system with respect to a margin of -0.05 (p = 0.000086). The mean interpretation time was 3 minutes 33 seconds per case without the CAD system and 2 minutes 24 seconds with it, for a difference of 1 minute 9 seconds saved (95% CI, 44-93 seconds; p = 0.000014), or a reduction in interpretation time to 67% of the time without the CAD system. Use of the concurrent-read CAD system for interpretation of screening ABUS studies of women with dense breast tissue who do not have symptoms is expected to make interpretation significantly faster and produce noninferior diagnostic accuracy compared with interpretation without the CAD system.

Computing Mass Properties From AutoCAD

NASA Technical Reports Server (NTRS)

Jones, A.

1990-01-01

Mass properties of structures computed from data in drawings. AutoCAD to Mass Properties (ACTOMP) computer program developed to facilitate quick calculations of mass properties of structures containing many simple elements in such complex configurations as trusses or sheet-metal containers. Mathematically modeled in AutoCAD or compatible computer-aided design (CAD) system in minutes by use of three-dimensional elements. Written in Microsoft Quick-Basic (Version 2.0).

A hybrid model for automatic identification of risk factors for heart disease.

PubMed

Yang, Hui; Garibaldi, Jonathan M

2015-12-01

Coronary artery disease (CAD) is the leading cause of death in both the UK and worldwide. The detection of related risk factors and tracking their progress over time is of great importance for early prevention and treatment of CAD. This paper describes an information extraction system that was developed to automatically identify risk factors for heart disease in medical records while the authors participated in the 2014 i2b2/UTHealth NLP Challenge. Our approaches rely on several nature language processing (NLP) techniques such as machine learning, rule-based methods, and dictionary-based keyword spotting to cope with complicated clinical contexts inherent in a wide variety of risk factors. Our system achieved encouraging performance on the challenge test data with an overall micro-averaged F-measure of 0.915, which was competitive to the best system (F-measure of 0.927) of this challenge task. Copyright © 2015 Elsevier Inc. All rights reserved.

Pre-test probability of obstructive coronary stenosis in patients undergoing coronary CT angiography: Comparative performance of the modified diamond-Forrester algorithm versus methods incorporating cardiovascular risk factors.

PubMed

Ferreira, António Miguel; Marques, Hugo; Tralhão, António; Santos, Miguel Borges; Santos, Ana Rita; Cardoso, Gonçalo; Dores, Hélder; Carvalho, Maria Salomé; Madeira, Sérgio; Machado, Francisco Pereira; Cardim, Nuno; de Araújo Gonçalves, Pedro

2016-11-01

Current guidelines recommend the use of the Modified Diamond-Forrester (MDF) method to assess the pre-test likelihood of obstructive coronary artery disease (CAD). We aimed to compare the performance of the MDF method with two contemporary algorithms derived from multicenter trials that additionally incorporate cardiovascular risk factors: the calculator-based 'CAD Consortium 2' method, and the integer-based CONFIRM score. We assessed 1069 consecutive patients without known CAD undergoing coronary CT angiography (CCTA) for stable chest pain. Obstructive CAD was defined as the presence of coronary stenosis ≥50% on 64-slice dual-source CT. The three methods were assessed for calibration, discrimination, net reclassification, and changes in proposed downstream testing based upon calculated pre-test likelihoods. The observed prevalence of obstructive CAD was 13.8% (n=147). Overestimations of the likelihood of obstructive CAD were 140.1%, 9.8%, and 18.8%, respectively, for the MDF, CAD Consortium 2 and CONFIRM methods. The CAD Consortium 2 showed greater discriminative power than the MDF method, with a C-statistic of 0.73 vs. 0.70 (p<0.001), while the CONFIRM score did not (C-statistic 0.71, p=0.492). Reclassification of pre-test likelihood using the 'CAD Consortium 2' or CONFIRM scores resulted in a net reclassification improvement of 0.19 and 0.18, respectively, which would change the diagnostic strategy in approximately half of the patients. Newer risk factor-encompassing models allow for a more precise estimation of pre-test probabilities of obstructive CAD than the guideline-recommended MDF method. Adoption of these scores may improve disease prediction and change the diagnostic pathway in a significant proportion of patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A plant-based diet, atherogenesis, and coronary artery disease prevention.

PubMed

Tuso, Phillip; Stoll, Scott R; Li, William W

2015-01-01

A plant-based diet is increasingly becoming recognized as a healthier alternative to a diet laden with meat. Atherosclerosis associated with high dietary intake of meat, fat, and carbohydrates remains the leading cause of mortality in the US. This condition results from progressive damage to the endothelial cells lining the vascular system, including the heart, leading to endothelial dysfunction. In addition to genetic factors associated with endothelial dysfunction, many dietary and other lifestyle factors, such as tobacco use, high meat and fat intake, and oxidative stress, are implicated in atherogenesis. Polyphenols derived from dietary plant intake have protective effects on vascular endothelial cells, possibly as antioxidants that prevent the oxidation of low-density lipoprotein. Recently, metabolites of L-carnitine, such as trimethylamine-N-oxide, that result from ingestion of red meat have been identified as a potential predictive marker of coronary artery disease (CAD). Metabolism of L-carnitine by the intestinal microbiome is associated with atherosclerosis in omnivores but not in vegetarians, supporting CAD benefits of a plant-based diet. Trimethylamine-N-oxide may cause atherosclerosis via macrophage activation. We suggest that a shift toward a plant-based diet may confer protective effects against atherosclerotic CAD by increasing endothelial protective factors in the circulation while reducing factors that are injurious to endothelial cells. The relative ratio of protective factors to injurious endothelial exposure may be a novel approach to assessing an objective dietary benefit from a plant-based diet. This review provides a mechanistic perspective of the evidence for protection by a plant-based diet against atherosclerotic CAD.

NASA-IGES Translator and Viewer

NASA Technical Reports Server (NTRS)

Chou, Jin J.; Logan, Michael A.

1995-01-01

NASA-IGES Translator (NIGEStranslator) is a batch program that translates a general IGES (Initial Graphics Exchange Specification) file to a NASA-IGES-Nurbs-Only (NINO) file. IGES is the most popular geometry exchange standard among Computer Aided Geometric Design (CAD) systems. NINO format is a subset of IGES, implementing the simple and yet the most popular NURBS (Non-Uniform Rational B-Splines) representation. NIGEStranslator converts a complex IGES file to the simpler NINO file to simplify the tasks of CFD grid generation for models in CAD format. The NASA-IGES Viewer (NIGESview) is an Open-Inventor-based, highly interactive viewer/ editor for NINO files. Geometry in the IGES files can be viewed, copied, transformed, deleted, and inquired. Users can use NIGEStranslator to translate IGES files from CAD systems to NINO files. The geometry then can be examined with NIGESview. Extraneous geometries can be interactively removed, and the cleaned model can be written to an IGES file, ready to be used in grid generation.

Computer-aided diagnosis in radiological imaging: current status and future challenges

NASA Astrophysics Data System (ADS)

Doi, Kunio

2009-10-01

Computer-aided diagnosis (CAD) has become one of the major research subjects in medical imaging and diagnostic radiology. Many different types of CAD schemes are being developed for detection and/or characterization of various lesions in medical imaging, including conventional projection radiography, CT, MRI, and ultrasound imaging. Commercial systems for detection of breast lesions on mammograms have been developed and have received FDA approval for clinical use. CAD may be defined as a diagnosis made by a physician who takes into account the computer output as a "second opinion". The purpose of CAD is to improve the quality and productivity of physicians in their interpretation of radiologic images. The quality of their work can be improved in terms of the accuracy and consistency of their radiologic diagnoses. In addition, the productivity of radiologists is expected to be improved by a reduction in the time required for their image readings. The computer output is derived from quantitative analysis of radiologic images by use of various methods and techniques in computer vision, artificial intelligence, and artificial neural networks (ANNs). The computer output may indicate a number of important parameters, for example, the locations of potential lesions such as lung cancer and breast cancer, the likelihood of malignancy of detected lesions, and the likelihood of various diseases based on differential diagnosis in a given image and clinical parameters. In this review article, the basic concept of CAD is first defined, and the current status of CAD research is then described. In addition, the potential of CAD in the future is discussed and predicted.

Development of a large scale Chimera grid system for the Space Shuttle Launch Vehicle

NASA Technical Reports Server (NTRS)

Pearce, Daniel G.; Stanley, Scott A.; Martin, Fred W., Jr.; Gomez, Ray J.; Le Beau, Gerald J.; Buning, Pieter G.; Chan, William M.; Chiu, Ing-Tsau; Wulf, Armin; Akdag, Vedat

1993-01-01

The application of CFD techniques to large problems has dictated the need for large team efforts. This paper offers an opportunity to examine the motivations, goals, needs, problems, as well as the methods, tools, and constraints that defined NASA's development of a 111 grid/16 million point grid system model for the Space Shuttle Launch Vehicle. The Chimera approach used for domain decomposition encouraged separation of the complex geometry into several major components each of which was modeled by an autonomous team. ICEM-CFD, a CAD based grid generation package, simplified the geometry and grid topology definition by provoding mature CAD tools and patch independent meshing. The resulting grid system has, on average, a four inch resolution along the surface.

Application of computer-aided dispatch in law enforcement: An introductory planning guide

NASA Technical Reports Server (NTRS)

Sohn, R. L.; Gurfield, R. M.; Garcia, E. A.; Fielding, J. E.

1975-01-01

A set of planning guidelines for the application of computer-aided dispatching (CAD) to law enforcement is presented. Some essential characteristics and applications of CAD are outlined; the results of a survey of systems in the operational or planning phases are summarized. Requirements analysis, system concept design, implementation planning, and performance and cost modeling are described and demonstrated with numerous examples. Detailed descriptions of typical law enforcement CAD systems, and a list of vendor sources, are given in appendixes.

Different CAD/CAM-processing routes for zirconia restorations: influence on fitting accuracy.

PubMed

Kohorst, Philipp; Junghanns, Janet; Dittmer, Marc P; Borchers, Lothar; Stiesch, Meike

2011-08-01

The aim of the present in vitro study was to evaluate the influence of different processing routes on the fitting accuracy of four-unit zirconia fixed dental prostheses (FDPs) fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM). Three groups of zirconia frameworks with ten specimens each were fabricated. Frameworks of one group (CerconCAM) were produced by means of a laboratory CAM-only system. The other frameworks were made with different CAD/CAM systems; on the one hand by in-laboratory production (CerconCAD/CAM) and on the other hand by centralized production in a milling center (Compartis) after forwarding geometrical data. Frameworks were then veneered with the recommended ceramics, and marginal accuracy was determined using a replica technique. Horizontal marginal discrepancy, vertical marginal discrepancy, absolute marginal discrepancy, and marginal gap were evaluated. Statistical analyses were performed by one-way analysis of variance (ANOVA), with the level of significance chosen at 0.05. Mean horizontal discrepancies ranged between 22 μm (CerconCAM) and 58 μm (Compartis), vertical discrepancies ranged between 63 μm (CerconCAD/CAM) and 162 μm (CerconCAM), and absolute marginal discrepancies ranged between 94 μm (CerconCAD/CAM) and 181 μm (CerconCAM). The marginal gap varied between 72 μm (CerconCAD/CAM) and 112 μm (CerconCAM, Compartis). Statistical analysis revealed that, with all measurements, the marginal accuracy of the zirconia FDPs was significantly influenced by the processing route used (p < 0.05). Within the limitations of this study, all restorations showed a clinically acceptable marginal accuracy; however, the results suggest that the CAD/CAM systems are more precise than the CAM-only system for the manufacture of four-unit FDPs.

Network-Based Identification and Prioritization of Key Regulators of Coronary Artery Disease Loci

PubMed Central

Zhao, Yuqi; Chen, Jing; Freudenberg, Johannes M.; Meng, Qingying; Rajpal, Deepak K.; Yang, Xia

2017-01-01

Objective Recent genome-wide association studies of coronary artery disease (CAD) have revealed 58 genome-wide significant and 148 suggestive genetic loci. However, the molecular mechanisms through which they contribute to CAD and the clinical implications of these findings remain largely unknown. We aim to retrieve gene subnetworks of the 206 CAD loci and identify and prioritize candidate regulators to better understand the biological mechanisms underlying the genetic associations. Approach and Results We devised a new integrative genomics approach that incorporated (1) candidate genes from the top CAD loci, (2) the complete genetic association results from the 1000 genomes-based CAD genome-wide association studies from the Coronary Artery Disease Genome Wide Replication and Meta-Analysis Plus the Coronary Artery Disease consortium, (3) tissue-specific gene regulatory networks that depict the potential relationship and interactions between genes, and (4) tissue-specific gene expression patterns between CAD patients and controls. The networks and top-ranked regulators according to these data-driven criteria were further queried against literature, experimental evidence, and drug information to evaluate their disease relevance and potential as drug targets. Our analysis uncovered several potential novel regulators of CAD such as LUM and STAT3, which possess properties suitable as drug targets. We also revealed molecular relations and potential mechanisms through which the top CAD loci operate. Furthermore, we found that multiple CAD-relevant biological processes such as extracellular matrix, inflammatory and immune pathways, complement and coagulation cascades, and lipid metabolism interact in the CAD networks. Conclusions Our data-driven integrative genomics framework unraveled tissue-specific relations among the candidate genes of the CAD genome-wide association studies loci and prioritized novel network regulatory genes orchestrating biological processes relevant to CAD. PMID:26966275

Interval training based on ventilatory anaerobic threshold improves aerobic functional capacity and metabolic profile: a randomized controlled trial in coronary artery disease patients.

PubMed

Tamburús, Nayara Y; Kunz, Vandeni C; Salviati, Mariana R; Castello Simões, Viviane; Catai, Aparecida M; Da Silva, Ester

2016-02-01

Exercise training has been an essential component of cardiac rehabilitation. However, it is not known if interval training (IT) based on the ventilatory anaerobic threshold (VAT) could be effective in improving aerobic functional capacity and metabolic profile in patients without or with coronary artery disease (CAD). To investigate the effects of an IT program, based-intensity between 70-110% of workload reached at the VAT, on the aerobic functional capacity and metabolic profile of patients with and without CAD. Randomized controlled trial. Outpatients from a cardiac rehabilitation. A sample was composed of 32 patients with CAD (CAD group) and 32 patients without CAD (noCAD group) that were randomized into a trained or control groups. Submaximal cardiopulmonary exercise test on the cycle ergometer and blood samples were realized at baseline and post 16 weeks of IT program. The cardiorespiratory variables were obtained at the VAT level. Trained groups (CAD-T, N.=15; noCAD-T, N.=15) underwent a supervised three-week session IT program (30-40 minutes each exercise session, at the intensity workloads equivalent to %VAT [70-110%]) for 16 weeks. After 16 weeks of IT program, there were a significant increase of VO(2VAT) and workload in the trained groups (P<0.05), while in the control groups VO(2VAT) and heart rate decreased (P<0.05). Body mass and body index mass decreased in trained groups (P<0.05), and low-density lipoprotein increased only in noCAD group after 16 weeks (P<0.05). The magnitude of the improvement in VO(2VAT) was related to VO(2VAT) (r=-0.57, P<0.05) and workload (r=-0.52, P<0.05) at baseline. The IT program prescribed with intensities based on VAT improved the aerobic functional capacity and decreased body mass and body index mass loss in patients with and without CAD. IT program based on VAT provides new possibilities for cardiac rehabilitation in relation to individualized exercise prescription of the interval training.

Optimizing computer-aided colonic polyp detection for CT colonography by evolving the Pareto front1

PubMed Central

Li, Jiang; Huang, Adam; Yao, Jack; Liu, Jiamin; Van Uitert, Robert L.; Petrick, Nicholas; Summers, Ronald M.

2009-01-01

A multiobjective genetic algorithm is designed to optimize a computer-aided detection (CAD) system for identifying colonic polyps. Colonic polyps appear as elliptical protrusions on the inner surface of the colon. Curvature-based features for colonic polyp detection have proved to be successful in several CT colonography (CTC) CAD systems. Our CTC CAD program uses a sequential classifier to form initial polyp detections on the colon surface. The classifier utilizes a set of thresholds on curvature-based features to cluster suspicious colon surface regions into polyp candidates. The thresholds were previously chosen experimentally by using feature histograms. The chosen thresholds were effective for detecting polyps sized 10 mm or larger in diameter. However, many medium-sized polyps, 6–9 mm in diameter, were missed in the initial detection procedure. In this paper, the task of finding optimal thresholds as a multiobjective optimization problem was formulated, and a genetic algorithm to solve it was utilized by evolving the Pareto front of the Pareto optimal set. The new CTC CAD system was tested on 792 patients. The sensitivities of the optimized system improved significantly, from 61.68% to 74.71% with an increase of 13.03% (95% CI [6.57%, 19.5%], p=7.78×10−5) for the size category of 6–9 mm polyps, from 65.02% to 77.4% with an increase of 12.38% (95% CI [6.23%, 18.53%], p=7.95×10−5) for polyps 6 mm or larger, and from 82.2% to 90.58% with an increase of 8.38% (95%CI [0.75%, 16%], p=0.03) for polyps 8 mm or larger at comparable false positive rates. The sensitivities of the optimized system are nearly equivalent to those of expert radiologists. PMID:19235388

CAD/CAM at a Distance: Assessing the Effectiveness of Web-Based Instruction To Meet Workforce Development Needs. AIR 2000 Annual Forum Paper.

ERIC Educational Resources Information Center

Wilkerson, Joyce A.; Elkins, Susan A.

This qualitative case study assessed web-based instruction in a computer-aided design/computer-assisted manufacturing (CAD/CAM) course designed for workforce development. The study examined students' and instructors' experience in a CAD/CAM course delivered exclusively on the Internet, evaluating course content and delivery, clarity of…

Mobile Technology and CAD Technology Integration in Teaching Architectural Design Process for Producing Creative Product

ERIC Educational Resources Information Center

Bin Hassan, Isham Shah; Ismail, Mohd Arif; Mustafa, Ramlee

2011-01-01

The purpose of this research is to examine the effect of integrating the mobile and CAD technology on teaching architectural design process for Malaysian polytechnic architectural students in producing a creative product. The website is set up based on Caroll's minimal theory, while mobile and CAD technology integration is based on Brown and…

CAD-based Automatic Modeling Method for Geant4 geometry model Through MCAM

NASA Astrophysics Data System (ADS)

Wang, Dong; Nie, Fanzhi; Wang, Guozhong; Long, Pengcheng; LV, Zhongliang; LV, Zhongliang

2014-06-01

Geant4 is a widely used Monte Carlo transport simulation package. Before calculating using Geant4, the calculation model need be established which could be described by using Geometry Description Markup Language (GDML) or C++ language. However, it is time-consuming and error-prone to manually describe the models by GDML. Automatic modeling methods have been developed recently, but there are some problem existed in most of present modeling programs, specially some of them were not accurate or adapted to specifically CAD format. To convert the GDML format models to CAD format accurately, a Geant4 Computer Aided Design (CAD) based modeling method was developed for automatically converting complex CAD geometry model into GDML geometry model. The essence of this method was dealing with CAD model represented with boundary representation (B-REP) and GDML model represented with constructive solid geometry (CSG). At first, CAD model was decomposed to several simple solids which had only one close shell. And then the simple solid was decomposed to convex shell set. Then corresponding GDML convex basic solids were generated by the boundary surfaces getting from the topological characteristic of a convex shell. After the generation of these solids, GDML model was accomplished with series boolean operations. This method was adopted in CAD/Image-based Automatic Modeling Program for Neutronics & Radiation Transport (MCAM), and tested with several models including the examples in Geant4 install package. The results showed that this method could convert standard CAD model accurately, and can be used for Geant4 automatic modeling.

Achieving the desired colour in discoloured teeth, using leucite-based CAD-CAM laminate systems.

PubMed

Turgut, Sedanur; Bagis, Bora; Ayaz, Elif Aydogan

2014-01-01

To evaluate the cumulative effect of the abutment tooth and resin cement colour on the resultant optical properties of porcelain laminate veneers (PLVs) fabricated with leucite-based CAD/CAM blocks with different shades and thicknesses. A total of 224 ceramic specimens were prepared from the IPS Empress CAD with four different shades of HT-A1, LT-A1, MT-A1 and Bl-1. Resin composite discs were prepared with shade A3.5. For the cementation, 4 different shades of light-cure resin cements were chosen. L*, a*, and b* values, as well as the chroma (C) and hue (h) values of each cemented ceramic and the A1 shade table, were recorded. L*, Cab* and hab* values of the cemented ceramics were influenced by ceramic shade, ceramic thickness, cement shade, and interaction terms of the three variables. There were significant differences between the 1-mm-thick ceramic veneers that exhibited higher L* and lower Cab* values compared with veneers that were 0.5mm in thickness. Using the Tr shade cement resulted in lower L* and higher Cab* values for all thicknesses and ceramic shades, whereas the WO shade cement resulted in higher values. The selected colour of a laminate restoration is significantly affected by the ceramic shade, ceramic thickness and resin cement shade. Using the WO shade resin cement seems to be more effective in masking the discoloured abutment tooth. Clinicians should also select the translucency level of the ceramic block with the shade when a leucite-based CAD/CAM system is chosen to treat a discoloured tooth. Copyright © 2013 Elsevier Ltd. All rights reserved.

Restricted Boltzmann machines based oversampling and semi-supervised learning for false positive reduction in breast CAD.

PubMed

Cao, Peng; Liu, Xiaoli; Bao, Hang; Yang, Jinzhu; Zhao, Dazhe

2015-01-01

The false-positive reduction (FPR) is a crucial step in the computer aided detection system for the breast. The issues of imbalanced data distribution and the limitation of labeled samples complicate the classification procedure. To overcome these challenges, we propose oversampling and semi-supervised learning methods based on the restricted Boltzmann machines (RBMs) to solve the classification of imbalanced data with a few labeled samples. To evaluate the proposed method, we conducted a comprehensive performance study and compared its results with the commonly used techniques. Experiments on benchmark dataset of DDSM demonstrate the effectiveness of the RBMs based oversampling and semi-supervised learning method in terms of geometric mean (G-mean) for false positive reduction in Breast CAD.

Evaluation of serum Asymmetric Dimethyl Arginine concentrations in coronary artery disease patients without traditional cardiovascular risk factors.

PubMed

Ghayour-Mobarhan, Majid; Ayati, Nayyereh; Sahebkar, Amirhossein; Moohebati, Mohsen; Ayati, Narjes; Elyasi, Sepideh; Mohammadpour, Amir Houshang

2018-06-07

Previous studies have shown that Asymmetric Dimethyl Arginine (ADMA) is increased significantly during coronary artery diseases (CAD). However it is not clear either this increase is due to cardiovascular disease (CVD) risk factors or ADMA is increased independently in CAD. The aim of this study is to evaluate ADMA's plasma level as an independent biomarker in CADs. In current study a total of 165 subjects with no traditional CVD's RFs, who fulfilled the inclusion and exclusion criteria, were recruited; 55 CAD+ patients which had more than 50% stenosis (CAD+); 55 CAD- patients which had less than 50% stenosis in their coronary arteries (CAD-), based on their angiography record and 55 healthy individuals as controls. CAD+ patients were divided into three groups: single (SVD), double (2VD), and triple vessel (3VD) disease. Plasma level of soluble ADMA was measured with an enzyme-linked immono sorbent assay (ELISA) kit. No significant difference between ADMA's plasma levels was found between CAD+, CAD- and healthy groups. In addition ADMA's plasma levels was not significantly different between CAD+'s subgroups. The result of this study indicates no significant relation between ADMA's plasma levels and either presence or severity of coronary artery stenosis. Therefore, it is presumed that ADMA may not be an independent biomarker for CADs.

The application of CAD, CAE & CAM in development of butterfly valve’s disc

NASA Astrophysics Data System (ADS)

Asiff Razif Shah Ranjit, Muhammad; Hanie Abdullah, Nazlin

2017-06-01

The improved design of a butterfly valve disc is based on the concept of sandwich theory. Butterfly valves are mostly used in various industries such as oil and gas plant. The primary failure modes for valves are indented disc, keyways and shaft failure and the cavitation damage. Emphasis on the application of CAD, a new model of the butterfly valve’s disc structure was designed. The structure analysis was analysed using the finite element analysis. Butterfly valve performance factors can be obtained is by using Computational Fluid Dynamics (CFD) software to simulate the physics of fluid flow in a piping system around a butterfly valve. A comparison analysis was done using the finite element to justify the performance of the structure. The second application of CAE is the computational fluid flow analysis. The upstream pressure and the downstream pressure was analysed to calculate the cavitation index and determine the performance throughout each opening position of the valve. The CAM process was done using 3D printer to produce a prototype and analysed the structure in form of prototype. The structure was downscale fabricated based on the model designed initially through the application of CAD. This study is utilized the application of CAD, CAE and CAM for a better improvement of the butterfly valve’s disc components.

Automated knowledge generation

NASA Technical Reports Server (NTRS)

Myler, Harley R.; Gonzalez, Avelino J.

1988-01-01

The general objectives of the NASA/UCF Automated Knowledge Generation Project were the development of an intelligent software system that could access CAD design data bases, interpret them, and generate a diagnostic knowledge base in the form of a system model. The initial area of concentration is in the diagnosis of the process control system using the Knowledge-based Autonomous Test Engineer (KATE) diagnostic system. A secondary objective was the study of general problems of automated knowledge generation. A prototype was developed, based on object-oriented language (Flavors).

Shear Bond Strength of Repair Systems to New CAD/CAM Restorative Materials.

PubMed

Üstün, Özlem; Büyükhatipoğlu, Işıl Keçik; Seçilmiş, Aslı

2016-11-23

To evaluate the bond strength of repair systems (Ceramic Repair, Clearfil Repair) to computer-aided design/computer-assisted machining (CAD/CAM) restorative materials (IPS e.max CAD, Vita Suprinity, Vita Enamic, Lava Ultimate). Thermally aged CAD/CAM restorative material specimens (5000 cycles between 5°C and 55°C) were randomly divided into two groups according to the repair system: Ceramic Repair (37% phosphoric acid + Monobond-S + Heliobond + Tetric N Ceram) or Clearfil Repair (40% phosphoric acid + mixture of Clearfil Porcelain Bond Activator and Clearfil SE Bond Primer + Clearfil SE Bond + Filtek Z250). The resin composite was light-cured on conditioned specimens. All specimens were stored in distilled water at 37°C for 24 hours and then additionally aged for 5000 thermal cycles. The shear bond strength test was performed using a universal testing machine (0.5 mm/min). Two-way ANOVA was used to detect significance differences according to the CAD/CAM material and composite repair system factors. Subgroup analyses were conducted using the least significant difference post-hoc test. The results of two-way ANOVA indicated that bond strength values varied according to the restorative materials (p < 0.05). No significant differences were observed between the CAD/CAM restorative materials (p > 0.05), except in the Vita Suprinity group (p < 0.05). Moreover, no differences were observed between the repair systems. Both the Clearfil and Ceramic repair systems used in the study allow for successful repairs. © 2016 by the American College of Prosthodontists.

Format conversion between CAD data and GIS data based on ArcGIS

NASA Astrophysics Data System (ADS)

Xie, Qingqing; Wei, Bo; Zhang, Kailin; Wang, Zhichao

2015-12-01

To make full use of the data resources and realize a sharing for the different types of data in different industries, a method of format conversion between CAD data and GIS data based on ArcGIS was proposed. To keep the integrity of the converted data, some key steps to process CAD data before conversion were made in AutoCAD. For examples, deleting unnecessary elements such as title, border and legend avoided the appearance of unnecessary elements after conversion, as layering data again by a national standard avoided the different types of elements to appear in a same layer after conversion. In ArcGIS, converting CAD data to GIS data was executed by the correspondence of graphic element classification between AutoCAD and ArcGIS. In addition, an empty geographic database and feature set was required to create in ArcGIS for storing the text data of CAD data. The experimental results show that the proposed method avoids a large amount of editing work in data conversion and maintains the integrity of spatial data and attribute data between before and after conversion.

[The study on fabrication of dental restoration using PMMA-ZrO2 composites via CAD/CAM].

PubMed

Li, Shi-bao; Wang, Zhong-yi; Chen, Zhao-hui; Hu, Hai-feng; Tang, Li-hui; Ma, Chu-fan

2005-01-01

To obtain dental restorations by machining PMMA-ZrO2 organic-inorganic composites with the dental CAD/CAM system. Partially sintered Zirconia compacts (PSZC) were prepared via isostatic pressing and partially sintering, with Zirconia nanopowder as raw materials. PMMA-Zirconia organic-inorganic composites were prepared by vacuum infiltrating the prepolymerized MMA into the PSZC, followed by in-situ polymerization. The mechanical properties and machinability of composites were studied. The composites were machined on the dental CAD/CAM system to obtain dental restoration. At 71.44% TD of PSZC, the composite had a 3-point bending strength of (202.56 +/- 3.09) MPa, fracture toughness of (4.30 +/- 0.16) MPa.m(1/2), elasticity modulus of (58.71 +/- 1.98) GPa, and Vickers hardness of (3.82 +/- 0.34) GPa, respectively. A premolar crown was fabricated by CAD/CAM system in 16 mins, and was verisimilitude, without any cracks. The composite at 71.44% TD of PSZC has good mechanical properties and dental restorations can be manufactured by PMMA-Zirconia composites via dental CAD/CAM system.

Excretion of anti-angiogenic proteins in patients with chronic allograft dysfunction.

PubMed

Moskowitz-Kassai, Eliza; Mackelaite, Lina; Chen, Jun; Patel, Kaushal; Dadhania, Darshana M; Gross, Steven S; Chander, Praveen; Delaney, Vera; Deng, Luqin; Chen, Ligong; Cui, Xiangqin; Suthanthiran, Manikkam; Goligorsky, Michael S

2012-02-01

We have recently documented the appearance of an anti-angiogenic peptide, endorepellin, in the urine of patients with chronic allograft dysfunction (CAD). Here, we analyzed using enzyme-linked immunosorbent assay the excretion of anti-angiogenic peptides endostatin, pigment epithelium-derived factor (PEDF) and Kruppel-like factor-2 (KLF-2), in healthy individuals, patients with stable graft function and patients with various degrees of CAD. In healthy subjects and patients with CAD-0, endostatin, PEDF and KLF-2 excretions were at the level of detection. In contrast, there were significant differences between the patients with CAD-3 and CAD-0, CAD-1 and healthy controls for endostatin and CAD-0 versus CAD-3 for PEDF, but no differences in KLF-2 excretion. Receiver operating characteristic (ROC) curve analyses demonstrated a highly discriminative profile for all three biomarkers: the combination of these parameters offered 83% sensitivity and 90% specificity in distinguishing CAD-0 from CAD-1-3. The quality of these potential biomarkers of CAD was, however, highest in discriminating CAD status in biopsy-proven cases and dropped when CAD-0 was diagnosed based on clinical criteria. In conclusion, these findings indicate the diagnostic potential of urinary detection of endostatin, PEDF and to lesser degree KLF-2 and suggest a mechanistic role played by anti-angiogenic substances in the developing vasculopathy and vascular rarefaction in patients with CAD.

Genetic variants primarily associated with type 2 diabetes are related to coronary artery disease risk

PubMed Central

Jansen, Henning; Loley, Christina; Lieb, Wolfgang; Pencina, Michael J; Nelson, Christopher P; Kathiresan, Sekar; Peloso, Gina M; Voight, Benjamin F; Reilly, Muredach P; Assimes, Themistocles L; Boerwinkle, Eric; Hengstenberg, Christian; Laaksonen, Reijo; McPherson, Ruth; Roberts, Robert; Thorsteinsdottir, Unnur; Peters, Annette; Gieger, Christian; Rawal, Rajesh; Thompson, John R; König, Inke R; Vasan, Ramachandran S; Erdmann, Jeanette; Samani, Nilesh J; Schunkert, Heribert

2015-01-01

Background The mechanisms underlying the association between diabetes and coronary artery disease (CAD) risk are unclear. We aimed to assess this association by studying genetic variants that have been shown to associate with type 2 diabetes (T2DM). If the association between diabetes and CAD is causal, we expected to observe an association of these variants with CAD as well. Methods and Results We studied all genetic variants currently known to be associated with T2DM at a genome-wide significant level (p<5*10−8) in CARDIoGRAM, a genome-wide data-set of CAD including 22,233 CAD cases and 64,762 controls. Out of the 44 published T2DM SNPs 10 were significantly associated with CAD in CARDIoGRAM (OR>1, p<0.05), more than expected by chance (p=5.0*10−5). Considering all 44 SNPs, the average CAD risk observed per individual T2DM risk allele was 1.0076 (95% confidence interval (CI), 0.9973–1.0180). Such average risk increase was significantly lower than the increase expected based on i) the published effects of the SNPs on T2DM risk and ii) the effect of T2DM on CAD risk as observed in the Framingham Heart Study, which suggested a risk of 1.067 per allele (p=7.2*10−10 vs. the observed effect). Studying two risk scores based on risk alleles of the diabetes SNPs, one score using individual level data in 9856 subjects, and the second score on average effects of reported beta-coefficients from the entire CARDIoGRAM data-set, we again observed a significant - yet smaller than expected - association with CAD. Conclusions Our data indicate that an association between type 2 diabetes related SNPs and CAD exists. However, the effects on CAD risk appear to be by far lower than what would be expected based on the effects of risk alleles on T2DM and the effect of T2DM on CAD in the epidemiological setting. PMID:26074316

Image segmentation of pyramid style identifier based on Support Vector Machine for colorectal endoscopic images.

PubMed

Okamoto, Takumi; Koide, Tetsushi; Sugi, Koki; Shimizu, Tatsuya; Anh-Tuan Hoang; Tamaki, Toru; Raytchev, Bisser; Kaneda, Kazufumi; Kominami, Yoko; Yoshida, Shigeto; Mieno, Hiroshi; Tanaka, Shinji

2015-08-01

With the increase of colorectal cancer patients in recent years, the needs of quantitative evaluation of colorectal cancer are increased, and the computer-aided diagnosis (CAD) system which supports doctor's diagnosis is essential. In this paper, a hardware design of type identification module in CAD system for colorectal endoscopic images with narrow band imaging (NBI) magnification is proposed for real-time processing of full high definition image (1920 × 1080 pixel). A pyramid style image segmentation with SVMs for multi-size scan windows, which can be implemented on an FPGA with small circuit area and achieve high accuracy, is proposed for actual complex colorectal endoscopic images.

Integrated Computer-Aided Drafting Instruction (ICADI).

ERIC Educational Resources Information Center

Chen, C. Y.; McCampbell, David H.

Until recently, computer-aided drafting and design (CAD) systems were almost exclusively operated on mainframes or minicomputers and their cost prohibited many schools from offering CAD instruction. Today, many powerful personal computers are capable of performing the high-speed calculation and analysis required by the CAD application; however,…

Experiments to evolve toward a tangible user interface for computer-aided design parts assembly

NASA Astrophysics Data System (ADS)

Legardeur, Jeremy; Garreau, Ludovic; Couture, Nadine

2004-05-01

In this paper, we present the concepts of the ESKUA (Experimentation of a Kinesics System Usable for Assembly) platform that allows designers to carry out the assembly of mechanical CAD (Computer Aided Design) parts. This platform, based on tangible user interface lead taking into account assembly constraints from the beginning of the design phase and especially during the phase of CAD models manipulation. Our goal is to propose a working environment where the designer is confronted with real assembly constraints which are currently masked by existing CAD software functionalities. Thus, the platform is based on the handling of physical objects, called tangible interactors, which enable having a physical perception of the assembly constraints. In this goal, we have defined a typology of interactors based on concepts proposed in Design For Assembly methods. We present here the results of studies that led to the evolution of this first interactors set. One is concerning an experiment to evaluate the cognitive aspects of the use of interactors. The other is about an analysis of existing mechanical product and fasteners. We will show how these studies lead to the evolution of the interactors based on the functional surfaces use.

CAD/CAM data management needs, requirements and options

NASA Technical Reports Server (NTRS)

Lopatka, R. S.; Johnson, T. G.

1978-01-01

The requirements for a data management system in support of technical or scientific applications and possible courses of action were reviewed. Specific requirements were evolved while working towards higher level integration impacting all phases of the current design process and through examination of commercially marketed systems and related data base research. Arguments are proposed for varied approaches in implementing data base systems ranging from no action necessary to immediate procurement of an existing data base management system.

A completely automated CAD system for mass detection in a large mammographic database.

PubMed

Bellotti, R; De Carlo, F; Tangaro, S; Gargano, G; Maggipinto, G; Castellano, M; Massafra, R; Cascio, D; Fauci, F; Magro, R; Raso, G; Lauria, A; Forni, G; Bagnasco, S; Cerello, P; Zanon, E; Cheran, S C; Lopez Torres, E; Bottigli, U; Masala, G L; Oliva, P; Retico, A; Fantacci, M E; Cataldo, R; De Mitri, I; De Nunzio, G

2006-08-01

Mass localization plays a crucial role in computer-aided detection (CAD) systems for the classification of suspicious regions in mammograms. In this article we present a completely automated classification system for the detection of masses in digitized mammographic images. The tool system we discuss consists in three processing levels: (a) Image segmentation for the localization of regions of interest (ROIs). This step relies on an iterative dynamical threshold algorithm able to select iso-intensity closed contours around gray level maxima of the mammogram. (b) ROI characterization by means of textural features computed from the gray tone spatial dependence matrix (GTSDM), containing second-order spatial statistics information on the pixel gray level intensity. As the images under study were recorded in different centers and with different machine settings, eight GTSDM features were selected so as to be invariant under monotonic transformation. In this way, the images do not need to be normalized, as the adopted features depend on the texture only, rather than on the gray tone levels, too. (c) ROI classification by means of a neural network, with supervision provided by the radiologist's diagnosis. The CAD system was evaluated on a large database of 3369 mammographic images [2307 negative, 1062 pathological (or positive), containing at least one confirmed mass, as diagnosed by an expert radiologist]. To assess the performance of the system, receiver operating characteristic (ROC) and free-response ROC analysis were employed. The area under the ROC curve was found to be Az = 0.783 +/- 0.008 for the ROI-based classification. When evaluating the accuracy of the CAD against the radiologist-drawn boundaries, 4.23 false positives per image are found at 80% of mass sensitivity.

The Effects of Integrating Mobile and CAD Technology in Teaching Design Process for Malaysian Polytechnic Architecture Student in Producing Creative Product

ERIC Educational Resources Information Center

Hassan, Isham Shah; Ismail, Mohd Arif; Mustapha, Ramlee

2010-01-01

The purpose of this research is to examine the effect of integrating the digital media such as mobile and CAD technology on designing process of Malaysian polytechnic architecture students in producing a creative product. A website is developed based on Caroll's minimal theory, while mobile and CAD technology integration is based on Brown and…

Detection of benign prostatic hyperplasia nodules in T2W MR images using fuzzy decision forest

NASA Astrophysics Data System (ADS)

Lay, Nathan; Freeman, Sabrina; Turkbey, Baris; Summers, Ronald M.

2016-03-01

Prostate cancer is the second leading cause of cancer-related death in men MRI has proven useful for detecting prostate cancer, and CAD may further improve detection. One source of false positives in prostate computer-aided diagnosis (CAD) is the presence of benign prostatic hyperplasia (BPH) nodules. These nodules have a distinct appearance with a pseudo-capsule on T2 weighted MR images but can also resemble cancerous lesions in other sequences such as the ADC or high B-value images. Describing their appearance with hand-crafted heuristics (features) that also exclude the appearance of cancerous lesions is challenging. This work develops a method based on fuzzy decision forests to automatically learn discriminative features for the purpose of BPH nodule detection in T2 weighted images for the purpose of improving prostate CAD systems.

A voxel visualization and analysis system based on AutoCAD

NASA Astrophysics Data System (ADS)

Marschallinger, Robert

1996-05-01

A collection of AutoLISP programs is presented which enable the visualization and analysis of voxel models by AutoCAD rel. 12/rel. 13. The programs serve as an interactive, graphical front end for manipulating the results of three-dimensional modeling software producing block estimation data. ASCII data files describing geometry and attributes per estimation block are imported and stored as a voxel array. Each voxel may contain multiple attributes, therefore different parameters may be incorporated in one voxel array. Voxel classification is implemented on a layer basis providing flexible treatment of voxel classes such as recoloring, peeling, or volumetry. A versatile clipping tool enables slicing voxel arrays according to combinations of three perpendicular clipping planes. The programs feature an up-to-date, graphical user interface for user-friendly operation by non AutoCAD specialists.

A new 2D segmentation method based on dynamic programming applied to computer aided detection in mammography.

PubMed

Timp, Sheila; Karssemeijer, Nico

2004-05-01

Mass segmentation plays a crucial role in computer-aided diagnosis (CAD) systems for classification of suspicious regions as normal, benign, or malignant. In this article we present a robust and automated segmentation technique--based on dynamic programming--to segment mass lesions from surrounding tissue. In addition, we propose an efficient algorithm to guarantee resulting contours to be closed. The segmentation method based on dynamic programming was quantitatively compared with two other automated segmentation methods (region growing and the discrete contour model) on a dataset of 1210 masses. For each mass an overlap criterion was calculated to determine the similarity with manual segmentation. The mean overlap percentage for dynamic programming was 0.69, for the other two methods 0.60 and 0.59, respectively. The difference in overlap percentage was statistically significant. To study the influence of the segmentation method on the performance of a CAD system two additional experiments were carried out. The first experiment studied the detection performance of the CAD system for the different segmentation methods. Free-response receiver operating characteristics analysis showed that the detection performance was nearly identical for the three segmentation methods. In the second experiment the ability of the classifier to discriminate between malignant and benign lesions was studied. For region based evaluation the area Az under the receiver operating characteristics curve was 0.74 for dynamic programming, 0.72 for the discrete contour model, and 0.67 for region growing. The difference in Az values obtained by the dynamic programming method and region growing was statistically significant. The differences between other methods were not significant.

A Comparison of the Marginal and Internal Fit of Cobalt- Chromium Copings Fabricated by Two Different CAD/CAM Systems (CAD/ Milling, CAD/ Ceramill Sintron)

PubMed Central

Vojdani, Mahroo; Torabi, Kianoosh; Atashkar, Berivan; Heidari, Hossein; Torabi Ardakani, Mahshid

2016-01-01

Statement of the Problem: Marginal fitness is the most important criteria for evaluation of the clinical acceptability of a cast restoration. Marginal gap which is due to cement solubility and plaque retention is potentially detrimental to both tooth and periodontal tissues. Purpose: This in vitro study aimed to evaluate the marginal and internal fit of cobalt- chromium (Co-Cr) copings fabricated by two different CAD/CAM systems: (CAD/ milling and CAD/ Ceramill Sintron). Materials and Method: We prepared one machined standard stainless steel master model with following dimensions: 7 mm height, 5mm diameter, 90˚ shoulder marginal finish line with 1 mm width, 10˚ convergence angle and anti-rotational surface on the buccal aspect of the die. There were 10 copings produced from hard presintered Co-Cr blocks according to CAD/ Milling technique and ten copings from soft non- presintered Co-Cr blocks according to CAD/ Ceramill Sintron technique. Marginal and internal accuracies of copings were documented by the replica technique. Replicas were examined at ten reference points under a digital microscope (230X). The Student's t-test was used for statistical analysis. p< 0.001 was considered significant. Results: Statistically significant differences existed between the groups (p< 0.001). The CAD/milling group (hard copings) had a mean marginal discrepancy (MD) of 104 µm, axial discrepancy (AD) of 23 µm and occlusal discrepancy of 130 µm. For CAD/ Ceramill Sintron group, these values were 195 µm (MD), 46 µm (AD), and 232 µm (OD). Internal total discrepancy (ITD) for the CAD/milling group was 77 µm, whereas for the CAD/Ceramill Sintron group was 143 µm. Conclusion: Hard presintered Co-Cr copings had significantly higher marginal and internal accuracies compared to the soft non-presintered copings. PMID:27942545

Mass detection in digital breast tomosynthesis data using convolutional neural networks and multiple instance learning.

PubMed

Yousefi, Mina; Krzyżak, Adam; Suen, Ching Y

2018-05-01

Digital breast tomosynthesis (DBT) was developed in the field of breast cancer screening as a new tomographic technique to minimize the limitations of conventional digital mammography breast screening methods. A computer-aided detection (CAD) framework for mass detection in DBT has been developed and is described in this paper. The proposed framework operates on a set of two-dimensional (2D) slices. With plane-to-plane analysis on corresponding 2D slices from each DBT, it automatically learns complex patterns of 2D slices through a deep convolutional neural network (DCNN). It then applies multiple instance learning (MIL) with a randomized trees approach to classify DBT images based on extracted information from 2D slices. This CAD framework was developed and evaluated using 5040 2D image slices derived from 87 DBT volumes. The empirical results demonstrate that this proposed CAD framework achieves much better performance than CAD systems that use hand-crafted features and deep cardinality-restricted Bolzmann machines to detect masses in DBTs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Magnetic Resonance Imaging-Based Assessment of Carotid Atheroma: a Comparative Study of Patients with and without Coronary Artery Disease.

PubMed

Usman, Ammara; Sadat, Umar; Teng, Zhongzhao; Graves, Martin J; Boyle, Jonathan R; Varty, Kevin; Hayes, Paul D; Gillard, Jonathan H

2017-02-01

Functional magnetic resonance (MR) imaging of atheroma using contrast media enables assessment of the systemic severity of atherosclerosis in different arterial beds. Whether black-blood imaging has similar ability remains widely unexplored. In this study, we evaluate whether black-blood imaging can differentiate carotid plaques of patients with and without coronary artery disease (CAD) in terms of morphological and biomechanical features of plaque vulnerability, thereby allowing assessment of the systemic severity nature of atherosclerosis in different arterial beds. Forty-one patients with CAD and 59 patients without CAD underwent carotid black-blood MR imaging. Plaque components were segmented to identify large lipid core (LC), ruptured fibrous cap (FC), and plaque hemorrhage (PH). These segmented contours of plaque components were used to quantify maximum structural biomechanical stress. Patients with CAD and without CAD had comparable demographics and comorbidities. Both groups had comparable prevalence of morphological features of plaque vulnerability (FC rupture, 44% versus 41%, P = .90; PH, 58% versus 47%, P = .78; large LC, 32% versus 47%, P = .17), respectively. The maximum biomechanical stress was not significantly different for both groups (241versus 278 kPa, P = .14) respectively. Black-blood imaging does not appear to have the ability to differentiate between the morphological and biomechanical features of plaque vulnerability when comparing patients with and without symptomatic atherosclerotic disease in a distant arterial territory such as coronary artery. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Measurement of myocardial perfusion and infarction size using computer-aided diagnosis system for myocardial contrast echocardiography.

PubMed

Du, Guo-Qing; Xue, Jing-Yi; Guo, Yanhui; Chen, Shuang; Du, Pei; Wu, Yan; Wang, Yu-Hang; Zong, Li-Qiu; Tian, Jia-Wei

2015-09-01

Proper evaluation of myocardial microvascular perfusion and assessment of infarct size is critical for clinicians. We have developed a novel computer-aided diagnosis (CAD) approach for myocardial contrast echocardiography (MCE) to measure myocardial perfusion and infarct size. Rabbits underwent 15 min of coronary occlusion followed by reperfusion (group I, n = 15) or 60 min of coronary occlusion followed by reperfusion (group II, n = 15). Myocardial contrast echocardiography was performed before and 7 d after ischemia/reperfusion, and images were analyzed with the CAD system on the basis of eliminating particle swarm optimization clustering analysis. The myocardium was quickly and accurately detected using contrast-enhanced images, myocardial perfusion was quantitatively calibrated and a color-coded map calibrated by contrast intensity and automatically produced by the CAD system was used to outline the infarction region. Calibrated contrast intensity was significantly lower in infarct regions than in non-infarct regions, allowing differentiation of abnormal and normal myocardial perfusion. Receiver operating characteristic curve analysis documented that -54-pixel contrast intensity was an optimal cutoff point for the identification of infarcted myocardium with a sensitivity of 95.45% and specificity of 87.50%. Infarct sizes obtained using myocardial perfusion defect analysis of original contrast images and the contrast intensity-based color-coded map in computerized images were compared with infarct sizes measured using triphenyltetrazolium chloride staining. Use of the proposed CAD approach provided observers with more information. The infarct sizes obtained with myocardial perfusion defect analysis, the contrast intensity-based color-coded map and triphenyltetrazolium chloride staining were 23.72 ± 8.41%, 21.77 ± 7.8% and 18.21 ± 4.40% (% left ventricle) respectively (p > 0.05), indicating that computerized myocardial contrast echocardiography can accurately measure infarct size. On the basis of the results, we believe the CAD method can quickly and automatically measure myocardial perfusion and infarct size and will, it is hoped, be very helpful in clinical therapeutics. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Image Processing and Computer Aided Diagnosis in Computed Tomography of the Breast

DTIC Science & Technology

2007-03-01

TERMS breast imaging, breast CT, scatter compensation, denoising, CAD , Cone-beam CT 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...clinical projection images. The CAD tool based on signal known exactly (SKE) scenario is under development. Task 6: Test and compare the...performances of the CAD developed in Task 5 applied to processed projection data from Task 1 with the CAD performance on the projection data without Bayesian

Coronary artery endothelial dysfunction is present in HIV positive individuals without significant coronary artery disease

PubMed Central

IANTORNO, Micaela; SCHÄR, Michael; SOLEIMANIFARD, Sahar; BROWN, Todd T.; MOORE, Richard; BARDITCH-CROVO, Patricia; STUBER, Matthias; LAI, Shenghan; GERSTENBLITH, Gary; WEISS, Robert G.; HAYS, Allison G.

2017-01-01

Objective HIV+ individuals experience an increased burden of coronary artery disease (CAD) not adequately accounted for by traditional CAD risk factors. Coronary endothelial function (CEF), a barometer of vascular health, is depressed early in atherosclerosis and predicts future events but has not been studied in HIV+ individuals. We tested whether CEF is impaired in HIV+ subjects without CAD as compared to an HIV- population matched for cardiac risk factors. Design/Methods In this observational study, CEF was measured noninvasively by quantifying isometric handgrip exercise (IHE)-induced changes in coronary vasoreactivity with MRI in 18 participants with HIV but no CAD (HIV+CAD-, based on prior imaging), 36 age- and cardiac risk factor-matched healthy participants with neither HIV nor CAD (HIV-CAD-), 41 subjects with no HIV but with known CAD (HIV-CAD+) and 17 subjects with both HIV and CAD (HIV+CAD+). Results CEF was significantly depressed in HIV+CAD- subjects as compared to that of risk-factor-matched HIV-CAD- subjects (p<0.0001), and was depressed to the level of that in HIV- participants with established CAD. Mean IL-6 levels were higher in HIV+ participants (p<0.0001), and inversely related to CEF in the HIV+ subjects (p=0.007). Conclusions Marked coronary endothelial dysfunction is present in HIV+ subjects without significant CAD and is as severe as that in clinical CAD patients. Furthermore, endothelial dysfunction appears inversely related to the degree of inflammation in HIV+ subjects, as measured by IL-6. CEF testing in HIV+ patients may be useful for assessing cardiovascular risk and testing new CAD treatment strategies, including those targeting inflammation. PMID:28353539

Implementing a new curriculum for computer-assisted restorations in prosthetic dentistry.

PubMed

Schweyen, R; Beuer, F; Bochskanl, M; Hey, J

2018-05-01

Computer-aided design/computer-aided manufacturing (CAD/CAM) of fixed prosthetic restorations has gained popularity in the last decade. However, this field of dentistry has not been integrated in the dental curriculum at most universities. According to the method of Kern, a curriculum was designed and established on a voluntary basis in the prosthetic education of a German dental school. The success of the implementation was measured by evaluation carried out by the participants on a visual analogue scale. Furthermore, the clinical performance of the fabricated restorations was evaluated. Ninety-four percent of all students participated in the CAD/CAM curriculum indicating considerable interest. Nearly half of all students used the acquired knowledge to design crowns for their patients. All restorations fabricated by participants of the new CAD/CAM programme showed good clinical performance. By phasing-in the CAD/CAM training programme, independent CAD/CAM-based fabrication of all-ceramic crowns increased student's self-confidence in tooth preparation. A tendency was found that students using CAD/CAM technology prepared more teeth than their fellow students who did not use CAD/CAM technology. Further studies are required to investigate the influence of independent CAD/CAM-based single-crown fabrication on the quality of the preparation. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of denture cleaning on abrasion resistance and surface topography of polymerized CAD CAM acrylic resin denture base

PubMed Central

Shinawi, Lana Ahmed

2017-01-01

Background The application of computer-aided design computer-aided manufacturing (CAD CAM) technology in the fabrication of complete dentures, offers numerous advantages as it provides optimum fit and eliminates polymerization shrinkage of the acrylic base. Additionally, the porosity and surface roughness of CAD CAM resins is less compared to conventionally processed resins which leads to a decrease in the adhesion of bacteria on the denture base, which is associated with many conditions including halitosis and aspiration pneumonia in elderly denture wearers. Aim To evaluate the influence of tooth brushing with dentifrices on CAD CAM resin blocks in terms of abrasion resistance, surface roughness and scanning electron photomicrography. Methods This experimental study was carried out at the Faculty of Dentistry of King Abdulaziz University during 2016. A total of 40 rectangular shaped polymerized CAD CAM resin samples were subjected to 40.000 and 60.000 brushing strokes under a 200-gram vertical load simulating three years of tooth brushing strokes using commercially available denture cleaning dentifrice. Data were analyzed by SPSS version 20, using descriptive statistics and ANOVA. Results ANOVA test revealed a statistical significant weight loss of CAD CAM acrylic resin denture base specimens following 40.000 and 60.000 brushing strokes as well as a statistical significant change (p=0.0.5) in the surface roughness following brushing. The CAD CAM resin samples SEM baseline imaging revealed a relatively smooth homogenous surface, but following 40,000 and 60,000 brushing strokes, imaging displayed the presence of small scratches on the surface. Conclusion CAD CAM resin displayed a homogenous surface initially with low surface roughness that was significantly affected following simulating three years of manual brushing, but despite the significant weight loss, the findings are within the clinically acceptable limits. PMID:28713496

Effect of denture cleaning on abrasion resistance and surface topography of polymerized CAD CAM acrylic resin denture base.

PubMed

Shinawi, Lana Ahmed

2017-05-01

The application of computer-aided design computer-aided manufacturing (CAD CAM) technology in the fabrication of complete dentures, offers numerous advantages as it provides optimum fit and eliminates polymerization shrinkage of the acrylic base. Additionally, the porosity and surface roughness of CAD CAM resins is less compared to conventionally processed resins which leads to a decrease in the adhesion of bacteria on the denture base, which is associated with many conditions including halitosis and aspiration pneumonia in elderly denture wearers. To evaluate the influence of tooth brushing with dentifrices on CAD CAM resin blocks in terms of abrasion resistance, surface roughness and scanning electron photomicrography. This experimental study was carried out at the Faculty of Dentistry of King Abdulaziz University during 2016. A total of 40 rectangular shaped polymerized CAD CAM resin samples were subjected to 40.000 and 60.000 brushing strokes under a 200-gram vertical load simulating three years of tooth brushing strokes using commercially available denture cleaning dentifrice. Data were analyzed by SPSS version 20, using descriptive statistics and ANOVA. ANOVA test revealed a statistical significant weight loss of CAD CAM acrylic resin denture base specimens following 40.000 and 60.000 brushing strokes as well as a statistical significant change (p=0.0.5) in the surface roughness following brushing. The CAD CAM resin samples SEM baseline imaging revealed a relatively smooth homogenous surface, but following 40,000 and 60,000 brushing strokes, imaging displayed the presence of small scratches on the surface. CAD CAM resin displayed a homogenous surface initially with low surface roughness that was significantly affected following simulating three years of manual brushing, but despite the significant weight loss, the findings are within the clinically acceptable limits.

Development of CAD prototype system for Crohn's disease

NASA Astrophysics Data System (ADS)

Oda, Masahiro; Kitasaka, Takayuki; Furukawa, Kazuhiro; Watanabe, Osamu; Ando, Takafumi; Goto, Hidemi; Mori, Kensaku

2010-03-01

The purpose of this paper is to present a CAD prototype system for Crohn's disease. Crohn's disease causes inflammation or ulcers of the gastrointestinal tract. The number of patients of Crohn's disease is increasing in Japan. Symptoms of Crohn's disease include intestinal stenosis, longitudinal ulcers, and fistulae. Optical endoscope cannot pass through intestinal stenosis in some cases. We propose a new CAD system using abdominal fecal tagging CT images for efficient diagnosis of Crohn's disease. The system displays virtual unfolded (VU), virtual endoscopic, curved planar reconstruction, multi planar reconstruction, and outside views of both small and large intestines. To generate the VU views, we employ a small and large intestines extraction method followed by a simple electronic cleansing method. The intestine extraction is based on the region growing process, which uses a characteristic that tagged fluid neighbor air in the intestine. The electronic cleansing enables observation of intestinal wall under tagged fluid. We change the height of the VU views according to the perimeter of the intestine. In addition, we developed a method to enhance the longitudinal ulcer on views of the system. We enhance concave parts on the intestinal wall, which are caused by the longitudinal ulcer, based on local intensity structure analysis. We examined the small and the large intestines of eleven CT images by the proposed system. The VU views enabled efficient observation of the intestinal wall. The height change of the VU views helps finding intestinal stenosis on the VU views. The concave region enhancement made longitudinal ulcers clear on the views.

In vitro evaluation of marginal discrepancy of monolithic zirconia restorations fabricated with different CAD-CAM systems.

PubMed

Hamza, Tamer A; Sherif, Rana M

2017-06-01

Dental laboratories use different computer-aided design and computer-aided manufacturing (CAD-CAM) systems to fabricate fixed prostheses; however, limited evidence is available concerning which system provides the best marginal discrepancy. The purpose of this in vitro study was to evaluate the marginal fit of 5 different monolithic zirconia restorations milled with different CAD-CAM systems. Thirty monolithic zirconia crowns were fabricated on a custom-designed stainless steel die and were divided into 5 groups according to the type of monolithic zirconia crown and the CAD-CAM system used: group TZ, milled with an MCXL milling machine; group CZ, translucent zirconia milled with a motion milling machine; group ZZ, zirconia milled with a dental milling unit; group PZ, translucent zirconia milled with a zirconia milling unit; and group BZ, solid zirconia milled using an S1 VHF milling machine. The marginal fit was measured with a binocular microscope at an original magnification of ×100. The results were tabulated and statistically analyzed with 1-way ANOVA and post hoc surface range test, and pairwise multiple comparisons were made using Bonferroni correction (α=.05). The type of CAD-CAM used affected the marginal fit of the monolithic restoration. The mean (±SD) highest marginal discrepancy was recorded in group TZI at 39.3 ±2.3 μm, while the least mean marginal discrepancy was recorded in group IZ (22.8 ±8.9 μm). The Bonferroni post hoc test showed that group TZI was significantly different from all other groups tested (P<.05). Within the limitation of this in vitro study, all tested CAD-CAM systems produced monolithic zirconia restorations with clinically acceptable marginal discrepancies; however, the CAD-CAM system with the 5-axis milling unit produced the best marginal fit. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Immunoglobulins against Tyrosine Nitrated Epitopes in Coronary Artery Disease

PubMed Central

Thomson, Leonor; Tenopoulou, Margarita; Lightfoot, Richard; Tsika, Epida; Parastatidis, Ioannis; Martinez, Marissa; Greco, Todd M.; Doulias, Paschalis-Thomas; Wu, Yuping; Tang, W. H. Wilson; Hazen, Stanley L.; Ischiropoulos, Harry

2012-01-01

Background Several lines of evidence support a pathophysiological role of immunity in atherosclerosis. Tyrosine nitrated proteins, a footprint of oxygen and nitrogen derived oxidants generated by cells of the immune system, are enriched in atheromatous lesions and in circulation of coronary artery disease (CAD) subjects. However, the consequences of possible immune reactions triggered by the presence of nitrated proteins in subjects with clinically documented atherosclerosis have not been explored. Methods and Results Specific immunoglobulins that recognize 3-nitrotyrosine epitopes were identified in human lesions, as well as in circulation of CAD subjects. The levels of circulating immunoglobulins against 3-nitrotyrosine epitopes were quantified in CAD patients (n=374) and subjects without CAD (non CAD controls, n=313). A ten-fold increase in the mean level of circulating immunoglobulins against protein-bound 3-nitrotyrosine was documented in the CAD subjects (3.75 ± 1.8 μg antibody Eq/mL plasma vs. 0.36 ± 0.8 μg antibody Eq/mL plasma), and was strongly associated with angiographic evidence of significant CAD. Conclusions The results of this cross sectional study suggest that post-translational modification of proteins via nitration within atherosclerotic plaque-laden arteries and in circulation serve as neoepitopes for elaboration of immunoglobulins, thereby providing an association between oxidant production and the activation of the immune system in CAD. PMID:23081989

CAD system for automatic analysis of CT perfusion maps

NASA Astrophysics Data System (ADS)

Hachaj, T.; Ogiela, M. R.

2011-03-01

In this article, authors present novel algorithms developed for the computer-assisted diagnosis (CAD) system for analysis of dynamic brain perfusion, computer tomography (CT) maps, cerebral blood flow (CBF), and cerebral blood volume (CBV). Those methods perform both quantitative analysis [detection and measurement and description with brain anatomy atlas (AA) of potential asymmetries/lesions] and qualitative analysis (semantic interpretation of visualized symptoms). The semantic interpretation (decision about type of lesion: ischemic/hemorrhagic, is the brain tissue at risk of infraction or not) of visualized symptoms is done by, so-called, cognitive inference processes allowing for reasoning on character of pathological regions based on specialist image knowledge. The whole system is implemented in.NET platform (C# programming language) and can be used on any standard PC computer with.NET framework installed.

Representing spatial information in a computational model for network management

NASA Technical Reports Server (NTRS)

Blaisdell, James H.; Brownfield, Thomas F.

1994-01-01

While currently available relational database management systems (RDBMS) allow inclusion of spatial information in a data model, they lack tools for presenting this information in an easily comprehensible form. Computer-aided design (CAD) software packages provide adequate functions to produce drawings, but still require manual placement of symbols and features. This project has demonstrated a bridge between the data model of an RDBMS and the graphic display of a CAD system. It is shown that the CAD system can be used to control the selection of data with spatial components from the database and then quickly plot that data on a map display. It is shown that the CAD system can be used to extract data from a drawing and then control the insertion of that data into the database. These demonstrations were successful in a test environment that incorporated many features of known working environments, suggesting that the techniques developed could be adapted for practical use.

Review, Selection and Installation of a Rapid Prototype Machine

NASA Technical Reports Server (NTRS)

McEndree, Caryl

2008-01-01

The objective of this paper is to impress upon the reader the benefits and advantages of investing in rapid prototyping (additive manufacturing) technology thru the procurement of one or two new rapid prototyping machines and the creation of a new Prototype and Model Lab at the Kennedy Space Center (KSC). This new resource will be available to all of United Space Alliance, LLC (USA), enabling engineers from around the company to pursue a more effective means of communication and design with our co-workers, and our customer, the National Aeronautics and Space Administration (NASA). The Rapid Protoyping/3D printing industry mirrors the transition the CAD industry made several years ago, when companies were trying to justify the expenditure of converting to a 3D based system from a 2D based system. The advantages of using a 3D system seemed to be outweighed by the cost it would take to convert not only legacy 2D drawings into 3D models but the training of personnel to use the 3D CAD software. But the reality was that when a 3D CAD system is employed, it gives engineers a much greater ability to conceive new designs and the ability to engineer new tools and products much more effectively. Rapid Prototyping (RP) is the name given to a host of related technologies that are used to fabricate physical objects directly from Computer Aided Design (CAD) data sources. These methods are generally similar to each other in that they add and bond materials in a layer wise-fashion to form objects, instead of machining away material. The machines used in Rapid Prototyping are also sometimes referred to as Rapid Manufacturing machines due to the fact that some of the parts fabricated in a RP machine can be used as the finished product. The name "Rapid Prototyping" is really a misnomer. It is much more than prototypes and it is not always rapid.

Noise detection in heart sound recordings.

PubMed

Zia, Mohammad K; Griffel, Benjamin; Fridman, Vladimir; Saponieri, Cesare; Semmlow, John L

2011-01-01

Coronary artery disease (CAD) is the leading cause of death in the United States. Although progression of CAD can be controlled using drugs and diet, it is usually detected in advanced stages when invasive treatment is required. Current methods to detect CAD are invasive and/or costly, hence not suitable as a regular screening tool to detect CAD in early stages. Currently, we are developing a noninvasive and cost-effective system to detect CAD using the acoustic approach. This method identifies sounds generated by turbulent flow through partially narrowed coronary arteries to detect CAD. The limiting factor of this method is sensitivity to noises commonly encountered in the clinical setting. Because the CAD sounds are faint, these noises can easily obscure the CAD sounds and make detection impossible. In this paper, we propose a method to detect and eliminate noise encountered in the clinical setting using a reference channel. We show that our method is effective in detecting noise, which is essential to the success of the acoustic approach.

CAD tools for detector design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Womersley, J.; DiGiacomo, N.; Killian, K.

1990-04-01

Detailed detector design has traditionally been divided between engineering optimization for structural integrity and subsequent physicist evaluation. The availability of CAD systems for engineering design enables the tasks to be integrated by providing tools for particle simulation within the CAD system. We believe this will speed up detector design and avoid problems due to the late discovery of shortcomings in the detector. This could occur because of the slowness of traditional verification techniques (such as detailed simulation with GEANT). One such new particle simulation tool is described. It is being used with the I-DEAS CAD package for SSC detector designmore » at Martin-Marietta Astronautics and is to be released through the SSC Laboratory.« less

Multi-channel System for Beat to Beat QT Interval Variability and its Use in Screening for Coronary Artery Disease and Cardiomyopathy

NASA Technical Reports Server (NTRS)

Starc, V.; Schlegel, T. T.; Arenare, B.; Greco, E. C.; DePalma, J. L.; Nunez, T.; Medina, R.; Jugo, D.; Rahman, M. A.; Delgado, R.

2007-01-01

We investigated the ability of beat-to-beat QT interval variability (QTV) and related parameters to differentiate healthy individuals from patients with obstructive coronary artery disease (CAD) and cardiomyopathy (CM). For this purpose we developed a PC-based ECG software program that in real time, acquires, analyzes and displays QTV in each of the eight independent channels that constitute the 12-lead conventional ECG. The system also analyzes and displays the QTV from QT interval signals that are derived from multiple channels and from singular value decomposition (SVD) to substantially reduce the effect of noise and other artifacts on the QTV results. It also provides other useful SVD-related parameters such as the normalized 3-dimensional volume of the T wave (nTV) = 100*(rho(sub 2)*rho(sub 3)rho(sub 1^2). Advanced high-fidelity 12-lead ECG tests (approx. 5-min supine) were first performed on a "training set" of 99 individuals: 33 with ischemic or dilated CM and low ejection fraction (EF less than 40%); 33 with catheterization-proven obstructive CAD but normal EF; and 33 age-/gender-matched healthy controls. All QTV parameters that were studied for their accuracy in detecting CM and CAD significantly differentiated both CM and CAD from controls (p less than 0.0001). Retrospective areas under the ROC curve (AUC) of SDNN-QTV, rmsSD-QTV, and QTV Index (QTVI) for CM vs. controls in the lead V5 were 0.85, 0.90, and 0.99, respectively, and those for CAD vs. controls in the lead II were 0.82, 0.82, and 0.89. Other advanced ECG parameters, such as HFQRS RAZ score, LF Lomb of RRV or QRS-T angle, differentiated both CM and CAD from controls less significantly, with the respective AUC values of 0.89, 0.88 and 0.98 for CM vs. controls, and 0.73, 0.71 and 0.80 for CAD vs. controls. QTV parameters (especially QTVI, which is QTV as indexed to RRV) were, diagnostically speaking, amongst the best performing of the advanced ECG techniques studied thus far.

Coronary artery disease in Saudi Arabia.

PubMed

Al-Nozha, Mansour M; Arafah, Mohammed R; Al-Mazrou, Yaqoub Y; Al-Maatouq, Mohammed A; Khan, Nazeer B; Khalil, Mohamed Z; Al-Khadra, Akram H; Al-Marzouki, Khalid; Abdullah, Moheeb A; Al-Harthi, Saad S; Al-Shahid, Maie S; Nouh, Mohammed S; Al-Mobeireek, Abdulellah

2004-09-01

Coronary artery disease (CAD) is a major public health problem worldwide. To our knowledge, there is no national data available from community based studies on prevalence of CAD in the Kingdom of Saudi Arabia (KSA). Therefore, we designed this study with the objective to determine the prevalence of CAD among Saudis of both sexes, between the ages of 30-70-years in rural as well as urban communities. Further, to determine the prevalence and clinical pattern of the major modifiable risk factors for CAD among the same population. This work is part of a major national study on CAD in Saudis Study (CADISS). This is a community based study conducted by examining subjects in the age group of 30-70-years of selected households during 5-year period between 1995 and 2000 in KSA. Data were obtained from history using a validated questionnaire, and electrocardiography. The data were analyzed to provide prevalence of CAD and risk assessment model. Nine hundred and forty-four subjects, out of 17232 were diagnosed to have CAD. Thus, the overall prevalence of CAD obtained from this study is 5.5% in KSA. The prevalence in males and females were 6.6% and 4.4% (P<0.0001). Urban Saudis have a higher prevalence of 6.2% compared to rural Saudis of 4% (P<0.0001). The following variables are found to be statistically significant risk factors in KSA: age, male gender, body mass index (BMI), hypertension, current smoking, fasting blood glucose, fasting cholesterol and triglycerides. The overall prevalence of CAD in KSA is 5.5%. A national prevention program at community level as well as high risk groups should be implemented sooner to prevent the expected epidemic of CAD that we are seeing, beginning. Measures are needed to change lifestyle and to address the management of the metabolic syndrome, to reduce modifiable risk factors for CAD. A longitudinal study is needed to demonstrate the importance of reducing modifiable risk factors for CAD in KSA.

Translucency of zirconia copings made with different CAD/CAM systems.

PubMed

Baldissara, Paolo; Llukacej, Altin; Ciocca, Leonardo; Valandro, Felipe L; Scotti, Roberto

2010-07-01

Zirconia cores are reported to be less translucent than glass, lithium disilicate, or alumina cores. This could affect the esthetic appearance and the clinical choices made when using zirconia-based restorations. The purpose of this in vitro study was to evaluate the translucency of zirconia copings for single crowns fabricated using different CAD/CAM systems, using lithium disilicate glass ceramic as a control. Using impressions made from a stainless steel complete-crown master die, 9 stone cast replicas were fabricated, numbered, and distributed into 8 ceramic ZrO(2) CAD/CAM system groups (Lava Frame 0.3 and 0.5, IPS e.max ZirCAD, VITA YZ, Procera AllZircon, Digizon, DC Zircon, and Cercon Base) and to a lithium disilicate glass-ceramic control group (IPS e.max Press) using a simple computer-generated randomization method. From each die, the manufacturer's authorized milling centers supplied 5 copings per group without applying any dying technique to the ceramic base material. The copings were prepared to allow for a 40-mum cement layer and were of different thicknesses according to system specifications. Translucency was measured by the direct transmission method with a digital photoradiometer mounted in a dark chamber. The light source was a 150-W halogen lamp beam. Measurements were repeated 3 times for each specimen. Data obtained were analyzed using 1-way ANOVA and the Bonferroni multiple comparison test (alpha=.05). Among ZrO(2) copings, Lava (0.3 mm and 0.5 mm thick) showed the highest (P<.05) values of translucency measured as light flow units (3.572 + or - 018 x 10(3) lx and 3.181 + or - 0.13 x 10(3) lx, respectively). These values represent 71.7% and 63.9%, respectively, of the glass-ceramic control group (4.98 x 10(3) lx). All ZrO(2) copings demonstrated different levels of light transmission, with the 2 Lava specimens showing the highest values. Translucency of zirconia copings was significantly lower (P=.001) than that of the lithium disilicate glass-ceramic control. Copyright 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Computer-Aided Design in Further Education.

ERIC Educational Resources Information Center

Ingham, Peter, Ed.

This publication updates the 1982 occasional paper that was intended to foster staff awareness and assist colleges in Great Britain considering the use of computer-aided design (CAD) material in engineering courses. The paper begins by defining CAD and its place in the Integrated Business System with a brief discussion of the effect of CAD on the…

Dynamic Modeling and Simulation of an Underactuated System

NASA Astrophysics Data System (ADS)

Libardo Duarte Madrid, Juan; Ospina Henao, P. A.; González Querubín, E.

2017-06-01

In this paper, is used the Lagrangian classical mechanics for modeling the dynamics of an underactuated system, specifically a rotary inverted pendulum that will have two equations of motion. A basic design of the system is proposed in SOLIDWORKS 3D CAD software, which based on the material and dimensions of the model provides some physical variables necessary for modeling. In order to verify the results obtained, a comparison the CAD model simulated in the environment SimMechanics of MATLAB software with the mathematical model who was consisting of Euler-Lagrange’s equations implemented in Simulink MATLAB, solved with the ODE23tb method, included in the MATLAB libraries for the solution of systems of equations of the type and order obtained. This article also has a topological analysis of pendulum trajectories through a phase space diagram, which allows the identification of stable and unstable regions of the system.

External validation of Medicare claims codes for digital mammography and computer-aided detection.

PubMed

Fenton, Joshua J; Zhu, Weiwei; Balch, Steven; Smith-Bindman, Rebecca; Lindfors, Karen K; Hubbard, Rebecca A

2012-08-01

While Medicare claims are a potential resource for clinical mammography research or quality monitoring, the validity of key data elements remains uncertain. Claims codes for digital mammography and computer-aided detection (CAD), for example, have not been validated against a credible external reference standard. We matched Medicare mammography claims for women who received bilateral mammograms from 2003 to 2006 to corresponding mammography data from the Breast Cancer Surveillance Consortium (BCSC) registries in four U.S. states (N = 253,727 mammograms received by 120,709 women). We assessed the accuracy of the claims-based classifications of bilateral mammograms as either digital versus film and CAD versus non-CAD relative to a reference standard derived from BCSC data. Claims data correctly classified the large majority of film and digital mammograms (97.2% and 97.3%, respectively), yielding excellent agreement beyond chance (κ = 0.90). Claims data correctly classified the large majority of CAD mammograms (96.6%) but a lower percentage of non-CAD mammograms (86.7%). Agreement beyond chance remained high for CAD classification (κ = 0.83). From 2003 to 2006, the predictive values of claims-based digital and CAD classifications increased as the sample prevalences of each technology increased. Medicare claims data can accurately distinguish film and digital bilateral mammograms and mammograms conducted with and without CAD. The validity of Medicare claims data regarding film versus digital mammography and CAD suggests that these data elements can be useful in research and quality improvement. ©2012 AACR.

Machine learning techniques for breast cancer computer aided diagnosis using different image modalities: A systematic review.

PubMed

Yassin, Nisreen I R; Omran, Shaimaa; El Houby, Enas M F; Allam, Hemat

2018-03-01

The high incidence of breast cancer in women has increased significantly in the recent years. Physician experience of diagnosing and detecting breast cancer can be assisted by using some computerized features extraction and classification algorithms. This paper presents the conduction and results of a systematic review (SR) that aims to investigate the state of the art regarding the computer aided diagnosis/detection (CAD) systems for breast cancer. The SR was conducted using a comprehensive selection of scientific databases as reference sources, allowing access to diverse publications in the field. The scientific databases used are Springer Link (SL), Science Direct (SD), IEEE Xplore Digital Library, and PubMed. Inclusion and exclusion criteria were defined and applied to each retrieved work to select those of interest. From 320 studies retrieved, 154 studies were included. However, the scope of this research is limited to scientific and academic works and excludes commercial interests. This survey provides a general analysis of the current status of CAD systems according to the used image modalities and the machine learning based classifiers. Potential research studies have been discussed to create a more objective and efficient CAD systems. Copyright © 2017 Elsevier B.V. All rights reserved.

On the Use of CAD and Cartesian Methods for Aerodynamic Optimization

NASA Technical Reports Server (NTRS)

Nemec, M.; Aftosmis, M. J.; Pulliam, T. H.

2004-01-01

The objective for this paper is to present the development of an optimization capability for Curt3D, a Cartesian inviscid-flow analysis package. We present the construction of a new optimization framework and we focus on the following issues: 1) Component-based geometry parameterization approach using parametric-CAD models and CAPRI. A novel geometry server is introduced that addresses the issue of parallel efficiency while only sparingly consuming CAD resources; 2) The use of genetic and gradient-based algorithms for three-dimensional aerodynamic design problems. The influence of noise on the optimization methods is studied. Our goal is to create a responsive and automated framework that efficiently identifies design modifications that result in substantial performance improvements. In addition, we examine the architectural issues associated with the deployment of a CAD-based approach in a heterogeneous parallel computing environment that contains both CAD workstations and dedicated compute engines. We demonstrate the effectiveness of the framework for a design problem that features topology changes and complex geometry.

Development of a Dynamically Configurable, Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation: Second Year Progress Report

NASA Technical Reports Server (NTRS)

Afjeh, Abdollah A.; Reed, John A.

2003-01-01

Mesh generation has long been recognized as a bottleneck in the CFD process. While much research on automating the volume mesh generation process have been relatively successful,these methods rely on appropriate initial surface triangulation to work properly. Surface discretization has been one of the least automated steps in computational simulation due to its dependence on implicitly defined CAD surfaces and curves. Differences in CAD peometry engines manifest themselves in discrepancies in their interpretation of the same entities. This lack of "good" geometry causes significant problems for mesh generators, requiring users to "repair" the CAD geometry before mesh generation. The problem is exacerbated when CAD geometry is translated to other forms (e.g., IGES )which do not include important topological and construction information in addition to entity geometry. One technique to avoid these problems is to access the CAD geometry directly from the mesh generating software, rather than through files. By accessing the geometry model (not a discretized version) in its native environment, t h s a proach avoids translation to a format which can deplete the model of topological information. Our approach to enable models developed in the Denali software environment to directly access CAD geometry and functions is through an Application Programming Interface (API) known as CAPRI. CAPRI provides a layer of indirection through which CAD-specific data may be accessed by an application program using CAD-system neutral C and FORTRAN language function calls. CAPRI supports a general set of CAD operations such as truth testing, geometry construction and entity queries.

The association of ABO blood groups with extent of coronary atherosclerosis in Croatian patients suffering from chronic coronary artery disease.

PubMed

Karabuva, Svjetlana; Carević, Vedran; Radić, Mislav; Fabijanić, Damir

2013-01-01

The aim of study was to: 1) examine the relationship between ABO blood groups and extent of coronary atherosclerosis in patients with chronic coronary artery disease (CAD), 2) compare ABO blood groups distribution in CAD patients and general population, 3) examine possible differences in traditional risk factors frequency in CAD patients with different ABO blood groups. In the 646 chronic CAD patients (72.4% males) coronary angiograms were scored by quantitative assessment using multiple angiographic scoring system, Traditional risk factors were self reported or measured by standard methods. ABO blood distribution of patients was compared with group of 651 healthy blood donors (74.6% males). Among all ABO blood group patients there was no significant difference between the extent of coronary atherosclerosis with regard to all the three scoring systems: number of affected coronary arteries (P = 0.857), Gensini score (P = 0.818), and number of segments narrowed > 50% (P = 0.781). There was no significant difference in ABO blood group distribution between CAD patients and healthy blood donors. Among CAD patients, men with blood group AB were significantly younger than their pairs with non-AB blood groups (P = 0.008). Among CAD patients with AB blood group, males < 50 yrs were significantly overrepresented when compared with the non-AB groups (P = 0.003). No association between ABO blood groups and the extent of coronary atherosclerosis in Croatian CAD patients is observed. Observation that AB blood group might possibly identify Croatian males at risk to develop the premature CAD has to be tested in larger cohort of patients.

Complete Dentures Fabricated with CAD/CAM Technology and a Traditional Clinical Recording Method.

PubMed

Janeva, Nadica; Kovacevska, Gordana; Janev, Edvard

2017-10-15

The introduction of computer-aided design/computer-aided manufacturing (CAD/CAM) technology into complete denture (CD) fabrication ushered in a new era in removable prosthodontics. Commercially available CAD/CAM denture systems are expected to improve upon the disadvantages associated with conventional fabrication. The purpose of this report is to present the workflow involved in fabricating a CD with a traditional clinical recording method and CAD/CAM technology and to summarize the advantages to the dental practitioner and the patient.

Structural Modeling Using "Scanning and Mapping" Technique

NASA Technical Reports Server (NTRS)

Amos, Courtney L.; Dash, Gerald S.; Shen, J. Y.; Ferguson, Frederick; Noga, Donald F. (Technical Monitor)

2000-01-01

Supported by NASA Glenn Center, we are in the process developing a structural damage diagnostic and monitoring system for rocket engines, which consists of five modules: Structural Modeling, Measurement Data Pre-Processor, Structural System Identification, Damage Detection Criterion, and Computer Visualization. The function of the system is to detect damage as it is incurred by the engine structures. The scientific principle to identify damage is to utilize the changes in the vibrational properties between the pre-damaged and post-damaged structures. The vibrational properties of the pre-damaged structure can be obtained based on an analytic computer model of the structure. Thus, as the first stage of the whole research plan, we currently focus on the first module - Structural Modeling. Three computer software packages are selected, and will be integrated for this purpose. They are PhotoModeler-Pro, AutoCAD-R14, and MSC/NASTRAN. AutoCAD is the most popular PC-CAD system currently available in the market. For our purpose, it plays like an interface to generate structural models of any particular engine parts or assembly, which is then passed to MSC/NASTRAN for extracting structural dynamic properties. Although AutoCAD is a powerful structural modeling tool, the complexity of engine components requires a further improvement in structural modeling techniques. We are working on a so-called "scanning and mapping" technique, which is a relatively new technique. The basic idea is to producing a full and accurate 3D structural model by tracing on multiple overlapping photographs taken from different angles. There is no need to input point positions, angles, distances or axes. Photographs can be taken by any types of cameras with different lenses. With the integration of such a modeling technique, the capability of structural modeling will be enhanced. The prototypes of any complex structural components will be produced by PhotoModeler first based on existing similar components, then passed to AutoCAD for modification and correction of any discrepancies seen in the Photomodeler version of the 3Dmodel. These three software packages are fully compatible. The DXF file can be used to transfer drawings among those packages. To begin this entire process, we are using a small replica of an actual engine blade as a test object. This paper introduces the accomplishment of our recent work.

Apixaban in patients with atrial fibrillation and prior coronary artery disease: insights from the ARISTOTLE trial.

PubMed

Bahit, Maria Cecilia; Lopes, Renato D; Wojdyla, Daniel M; Hohnloser, Stefan H; Alexander, John H; Lewis, Basil S; Aylward, Philip E; Verheugt, Freek W A; Keltai, Matyas; Diaz, Rafael; Hanna, Michael; Granger, Christopher B; Wallentin, Lars

2013-12-10

A substantial portion of patients with atrial fibrillation (AF) also have coronary artery disease (CAD) and are at risk for coronary events. Warfarin is known to reduce these events, but increase the risk of bleeding. We assessed the effects of apixaban compared with warfarin in AF patients with and without prior CAD. In ARISTOTLE, 18,201 patients with AF were randomized to apixaban or warfarin. History of CAD was defined as documented CAD, prior myocardial infarction, and/or history of coronary revascularization. We analyzed baseline characteristics and clinical outcomes of patients with and without prior CAD and compared outcomes by randomized treatment using Cox models. A total of 6639 (36.5%) patients had prior CAD. These patients were more often male, more likely to have prior stroke, diabetes, and hypertension, and more often received aspirin at baseline (42.2% vs. 24.5%). The effects of apixaban were similar among patients with and without prior CAD on reducing stroke or systemic embolism and death from any cause (hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.71-1.27, P for interaction=0.12; HR 0.96, 95% CI 0.81-1.13, P for interaction=0.28). Rates of myocardial infarction were numerically lower with apixaban than warfarin among patients with and without prior CAD. The effect of apixaban on reducing major bleeding and intracranial hemorrhage was consistent in patients with and without CAD. In patients with AF, apixaban more often prevented stroke or systemic embolism and death and caused less bleeding than warfarin, regardless of the presence of prior CAD. Given the common occurrence of AF and CAD and the higher rates of cardiovascular events and death, our results indicate that apixaban may be a better treatment option than warfarin for these high-risk patients. © 2013.

Improving aircraft conceptual design - A PHIGS interactive graphics interface for ACSYNT

NASA Technical Reports Server (NTRS)

Wampler, S. G.; Myklebust, A.; Jayaram, S.; Gelhausen, P.

1988-01-01

A CAD interface has been created for the 'ACSYNT' aircraft conceptual design code that permits the execution and control of the design process via interactive graphics menus. This CAD interface was coded entirely with the new three-dimensional graphics standard, the Programmer's Hierarchical Interactive Graphics System. The CAD/ACSYNT system is designed for use by state-of-the-art high-speed imaging work stations. Attention is given to the approaches employed in modeling, data storage, and rendering.

Improving the performance of lesion-based computer-aided detection schemes of breast masses using a case-based adaptive cueing method

NASA Astrophysics Data System (ADS)

Tan, Maxine; Aghaei, Faranak; Wang, Yunzhi; Qian, Wei; Zheng, Bin

2016-03-01

Current commercialized CAD schemes have high false-positive (FP) detection rates and also have high correlations in positive lesion detection with radiologists. Thus, we recently investigated a new approach to improve the efficacy of applying CAD to assist radiologists in reading and interpreting screening mammograms. Namely, we developed a new global feature based CAD approach/scheme that can cue the warning sign on the cases with high risk of being positive. In this study, we investigate the possibility of fusing global feature or case-based scores with the local or lesion-based CAD scores using an adaptive cueing method. We hypothesize that the information from the global feature extraction (features extracted from the whole breast regions) are different from and can provide supplementary information to the locally-extracted features (computed from the segmented lesion regions only). On a large and diverse full-field digital mammography (FFDM) testing dataset with 785 cases (347 negative and 438 cancer cases with masses only), we ran our lesion-based and case-based CAD schemes "as is" on the whole dataset. To assess the supplementary information provided by the global features, we used an adaptive cueing method to adaptively adjust the original CAD-generated detection scores (Sorg) of a detected suspicious mass region based on the computed case-based score (Scase) of the case associated with this detected region. Using the adaptive cueing method, better sensitivity results were obtained at lower FP rates (<= 1 FP per image). Namely, increases of sensitivities (in the FROC curves) of up to 6.7% and 8.2% were obtained for the ROI and Case-based results, respectively.

Developing a new case based computer-aided detection scheme and an adaptive cueing method to improve performance in detecting mammographic lesions

PubMed Central

Tan, Maxine; Aghaei, Faranak; Wang, Yunzhi; Zheng, Bin

2017-01-01

The purpose of this study is to evaluate a new method to improve performance of computer-aided detection (CAD) schemes of screening mammograms with two approaches. In the first approach, we developed a new case based CAD scheme using a set of optimally selected global mammographic density, texture, spiculation, and structural similarity features computed from all four full-field digital mammography (FFDM) images of the craniocaudal (CC) and mediolateral oblique (MLO) views by using a modified fast and accurate sequential floating forward selection feature selection algorithm. Selected features were then applied to a “scoring fusion” artificial neural network (ANN) classification scheme to produce a final case based risk score. In the second approach, we combined the case based risk score with the conventional lesion based scores of a conventional lesion based CAD scheme using a new adaptive cueing method that is integrated with the case based risk scores. We evaluated our methods using a ten-fold cross-validation scheme on 924 cases (476 cancer and 448 recalled or negative), whereby each case had all four images from the CC and MLO views. The area under the receiver operating characteristic curve was AUC = 0.793±0.015 and the odds ratio monotonically increased from 1 to 37.21 as CAD-generated case based detection scores increased. Using the new adaptive cueing method, the region based and case based sensitivities of the conventional CAD scheme at a false positive rate of 0.71 per image increased by 2.4% and 0.8%, respectively. The study demonstrated that supplementary information can be derived by computing global mammographic density image features to improve CAD-cueing performance on the suspicious mammographic lesions. PMID:27997380

Fracture resistance of computer-aided design and computer-aided manufacturing ceramic crowns cemented on solid abutments.

PubMed

Stona, Deborah; Burnett, Luiz Henrique; Mota, Eduardo Gonçalves; Spohr, Ana Maria

2015-07-01

Because no information was found in the dental literature regarding the fracture resistance of all-ceramic crowns using CEREC (Sirona) computer-aided design and computer-aided manufacturing (CAD-CAM) system on solid abutments, the authors conducted a study. Sixty synOcta (Straumann) implant replicas and regular neck solid abutments were embedded in acrylic resin and randomly assigned (n = 20 per group). Three types of ceramics were used: feldspathic, CEREC VITABLOCS Mark II (VITA); leucite, IPS Empress CAD (Ivoclar Vivadent); and lithium disilicate, IPS e.max CAD (Ivoclar Vivadent). The crowns were fabricated by the CEREC CAD-CAM system. After receiving glaze, the crowns were cemented with RelyX U200 (3M ESPE) resin cement under load of 1 kilogram. For each ceramic, one-half of the specimens were subjected to the fracture resistance testing in a universal testing machine with a crosshead speed of 1 millimeter per minute, and the other half were subjected to the fractured resistance testing after 1,000,000 cyclic fatigue loading at 100 newtons. According to a 2-way analysis of variance, the interaction between the material and mechanical cycling was significant (P = .0001). According to a Tukey test (α = .05), the fracture resistance findings with or without cyclic fatigue loading were as follows, respectively: CEREC VITABLOCKS Mark II (405 N/454 N) was statistically lower than IPS Empress CAD (1169 N/1240 N) and IPS e.max CAD (1378 N/1025 N) (P < .05). The IPS Empress CAD and IPS e.max CAD did not differ statistically (P > .05). According to a t test, there was no statistical difference in the fracture resistance with and without cyclic fatigue loading for CEREC VITABLOCS Mark II and IPS Empress CAD (P > .05). For IPS e.max CAD, the fracture resistance without cyclic fatigue loading was statistically superior to that obtained with cyclic fatigue loading (P < .05). The IPS Empress CAD and IPS e.max CAD showed higher fracture resistance compared with CEREC VITABLOCS Mark II. The cyclic fatigue loading negatively influenced only IPS e.max CAD. The CEREC VITABLOCS Mark II, IPS Empress CAD, and IPS e.max CAD ceramic crowns cemented on solid abutments showed sufficient resistance to withstand normal chewing forces. Copyright © 2015 American Dental Association. Published by Elsevier Inc. All rights reserved.

[Establishment of database with standard 3D tooth crowns based on 3DS MAX].

PubMed

Cheng, Xiaosheng; An, Tao; Liao, Wenhe; Dai, Ning; Yu, Qing; Lu, Peijun

2009-08-01

The database with standard 3D tooth crowns has laid the groundwork for dental CAD/CAM system. In this paper, we design the standard tooth crowns in 3DS MAX 9.0 and create a database with these models successfully. Firstly, some key lines are collected from standard tooth pictures. Then we use 3DS MAX 9.0 to design the digital tooth model based on these lines. During the design process, it is important to refer to the standard plaster tooth model. After some tests, the standard tooth models designed with this method are accurate and adaptable; furthermore, it is very easy to perform some operations on the models such as deforming and translating. This method provides a new idea to build the database with standard 3D tooth crowns and a basis for dental CAD/CAM system.

An Evaluation of Internet-Based CAD Collaboration Tools

ERIC Educational Resources Information Center

Smith, Shana Shiang-Fong

2004-01-01

Due to the now widespread use of the Internet, most companies now require computer aided design (CAD) tools that support distributed collaborative design on the Internet. Such CAD tools should enable designers to share product models, as well as related data, from geographically distant locations. However, integrated collaborative design…

Conditional random field modelling of interactions between findings in mammography

NASA Astrophysics Data System (ADS)

Kooi, Thijs; Mordang, Jan-Jurre; Karssemeijer, Nico

2017-03-01

Recent breakthroughs in training deep neural network architectures, in particular deep Convolutional Neural Networks (CNNs), made a big impact on vision research and are increasingly responsible for advances in Computer Aided Diagnosis (CAD). Since many natural scenes and medical images vary in size and are too large to feed to the networks as a whole, two stage systems are typically employed, where in the first stage, small regions of interest in the image are located and presented to the network as training and test data. These systems allow us to harness accurate region based annotations, making the problem easier to learn. However, information is processed purely locally and context is not taken into account. In this paper, we present preliminary work on the employment of a Conditional Random Field (CRF) that is trained on top the CNN to model contextual interactions such as the presence of other suspicious regions, for mammography CAD. The model can easily be extended to incorporate other sources of information, such as symmetry, temporal change and various patient covariates and is general in the sense that it can have application in other CAD problems.

Computer Assisted Instructional Design for Computer-Based Instruction. Final Report. Working Papers.

ERIC Educational Resources Information Center

Russell, Daniel M.; Pirolli, Peter

Recent advances in artificial intelligence and the cognitive sciences have made it possible to develop successful intelligent computer-aided instructional systems for technical and scientific training. In addition, computer-aided design (CAD) environments that support the rapid development of such computer-based instruction have also been recently…

Experimental CAD Course Uses Low-Cost Systems.

ERIC Educational Resources Information Center

Wohlers, Terry

1984-01-01

Describes the outstanding results obtained when a department of industrial sciences used special software on microcomputers to teach computer-aided design (CAD) as an alternative to much more expensive equipment. The systems used and prospects for the future are also considered. (JN)

Systemic inflammation is higher in peripheral artery disease than in stable coronary artery disease.

PubMed

Rein, Philipp; Saely, Christoph H; Silbernagel, Günther; Vonbank, Alexander; Mathies, Rainer; Drexel, Heinz; Baumgartner, Iris

2015-04-01

The knowledge on the level of systemic inflammation in peripheral artery disease (PAD) is less well established than that in coronary artery disease (CAD). Systemic inflammation frequently coincides with atherosclerosis, but also with various traits of the metabolic syndrome (MetS). The individual contribution of CAD, PAD, and the MetS to inflammation is not known. We enrolled a total of 1396 patients, 460 patients with PAD Fontaine stages IIa-IV verified by duplex ultrasound (PAD group) and 936 patients free of limb claudication undergoing coronary angiography, of whom 507 had significant CAD with coronary stenoses ≥50% (CAD group), and 429 did not have significant CAD at angiography (control group). C-reactive protein (CRP) was significantly higher in the PAD than in the CAD or in the control group (0.86 ± 1.85 mg/dl versus 0.44 ± 0.87 mg/dl and 0.39 ± 0.52 mg/dl, respectively, p < 0.001 for both comparisons). These significant differences were confirmed when patients with and subjects without the MetS were analyzed separately. In particular, within the PAD group, CRP was significantly higher in patients with the MetS than in subjects without the MetS (1.04 ± 2.01 vs. 0.67 ± 1.64 mg/dl; p = 0.001) and both, the presence of PAD and the MetS proved to be independently associated with CRP in analysis of covariance (F = 31.84; p < 0.001 and F = 10.52; p = 0.001, respectively). Inflammatory activity in PAD patients is higher than in CAD patients and is particularly high in PAD patients affected by the MetS. Low grade systemic inflammation is independently associated with both the MetS and PAD. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Effectiveness of computer aided detection for solitary pulmonary nodules

NASA Astrophysics Data System (ADS)

Yan, Jiayong; Li, Wenjie; Du, Xiangying; Lu, Huihai; Xu, Jianrong; Xu, Mantao; Rong, Dongdong

2009-02-01

This study is to investigate the incremental effect of using a high performance computer-aided detection (CAD) system in detection of solitary pulmonary nodules in chest radiographs. The Kodak Chest CAD system was evaluated by a panel of six radiologists at different levels of experience. The observer study consisted of two independent phases: readings without CAD and readings with assistance of CAD. The study was conducted over a set of chest radiographs comprising 150 cancer cases and 150 cancer-free cases. The actual sensitivity of the CAD system is 72% with 3.7 false positives per case. Receiver operating characteristic (ROC) analysis was used to assess the overall observer performance. The AUZ (area under ROC curve) showed a significantly improvement (P=0.0001) from 0.844 to 0.884 after using CAD. The ROC analysis was also applied for observer performances on nodules in different sizes and visibilities. The average AUZs are improved from 0.798 to 0.835 (P=0.0003) for 5-10mm nodules, 0.853 to 0.907 (P=0.001) for 10-15mm nodules, 0.864 to 0.897 (P=0.051) for 15-20 mm nodules and 0.859 to 0.896 (P=0.0342) for 20-30mm nodules, respectively. For different visibilities, the average AUZs are improved from 0.886 to 0.915 (P=0.0337), 0.803 to 0.840 (P=0.063), 0.830 to 0.893 (P=0.0001), and 0.813 to 0.847 (P=0.152), for nodules clearly visible, hidden by ribs, partially overlap with ribs, and overlap with other structures, respectively. These results showed that observer performance could be greatly improved when the CAD system is employed as a second reader, especially for small nodules and nodules occluded by ribs.

Analysis on the workspace of palletizing robot based on AutoCAD

NASA Astrophysics Data System (ADS)

Li, Jin-quan; Zhang, Rui; Guan, Qi; Cui, Fang; Chen, Kuan

2017-10-01

In this paper, a four-degree-of-freedom articulated palletizing robot is used as the object of research. Based on the analysis of the overall configuration of the robot, the kinematic mathematical model is established by D-H method to figure out the workspace of the robot. In order to meet the needs of design and analysis, using AutoCAD secondary development technology and AutoLisp language to develop AutoCAD-based 2D and 3D workspace simulation interface program of palletizing robot. At last, using AutoCAD plugin, the influence of structural parameters on the shape and position of the working space is analyzed when the structure parameters of the robot are changed separately. This study laid the foundation for the design, control and planning of palletizing robots.

Replacing Ambulatory Surgical Follow-Up Visits With Mobile App Home Monitoring: Modeling Cost-Effective Scenarios

PubMed Central

Semple, John L; Coyte, Peter C

2014-01-01

Background Women’s College Hospital (WCH) offers specialized surgical procedures, including ambulatory breast reconstruction in post-mastectomy breast cancer patients. Most patients receiving ambulatory surgery have low rates of postoperative events necessitating clinic visits. Increasingly, mobile monitoring and follow-up care is used to overcome the distance patients must travel to receive specialized care at a reduced cost to society. WCH has completed a feasibility study using a mobile app (QoC Health Inc, Toronto) that suggests high patient satisfaction and adequate detection of postoperative complications. Objective The proposed cost-effectiveness study models the replacement of conventional, in-person postoperative follow-up care with mobile app follow-up care following ambulatory breast reconstruction in post-mastectomy breast cancer patients. Methods This is a societal perspective cost-effectiveness analysis, wherein all costs are assessed irrespective of the payer. The patient/caregiver, health care system, and externally borne costs are calculated within the first postoperative month based on cost information provided by WCH and QoC Health Inc. The effectiveness of telemedicine and conventional follow-up care is measured as successful surgical outcomes at 30-days postoperative, and is modeled based on previous clinical trials containing similar patient populations and surgical risks. Results This costing assumes that 1000 patients are enrolled in bring-your-own-device (BYOD) mobile app follow-up per year and that 1.64 in-person follow-ups are attended in the conventional arm within the first month postoperatively. The total cost difference between mobile app and in-person follow-up care is $245 CAD ($223 USD based on the current exchange rate), with in-person follow-up being more expensive ($381 CAD) than mobile app follow-up care ($136 CAD). This takes into account the total of health care system, patient, and external borne costs. If we examine health care system costs alone, in-person follow-up is $38 CAD ($35 USD) more expensive than mobile app follow-up care over the first postoperative month. The baseline difference in effect is modeled to be zero based on clinical trials examining the effectiveness of telephone follow-up care in similar patient populations. An incremental cost-effectiveness ratio (ICER) is not reportable in this scenario. An incremental net benefit (INB) is reportable, and reflects merely the cost difference between the two interventions for any willingness-to-pay value (INB=$245 CAD). The cost-effectiveness of mobile app follow-up even holds in scenarios where all mobile patients attend one in-person follow-up. Conclusions Mobile app follow-up care is suitably targeted to low-risk postoperative ambulatory patients. It can be cost-effective from a societal and health care system perspective. PMID:25245774

Computer-aided detection of acute pulmonary embolism with 64-slice multi-detector row computed tomography: impact of the scanning conditions and overall image quality in the detection of peripheral clots.

PubMed

Dewailly, Marion; Rémy-Jardin, Martine; Duhamel, Alain; Faivre, Jean-Baptiste; Pontana, François; Deken, Valérie; Bakai, Anne-Marie; Remy, Jacques

2010-01-01

To evaluate the performance of a computer-aided detection (CAD) system for diagnosing peripheral acute pulmonary embolism (PE) with a 64-slice multi-detector row computed tomography (CT). Two radiologists investigated the accuracy of a software aimed at detecting peripheral clots (PECAD prototype, version 7; Siemens Medical Systems, Forchheim, Germany) by applying this tool for the analysis of the pulmonary arterial bed of 74 CT angiograms obtained with 64-slice dual-source CT (Definition; Siemens Medical Systems). These cases were retrospectively selected from a database of CT studies performed on the same CT unit, with a similar collimation (64 x 0.6 mm) and similar injection protocols. Patient selection was based on a variety of (1) scanning conditions, namely, nongated (n = 30), electrocardiography-gated (n = 30), and dual-energy CT angiograms (n = 14), and (2) image quality (IQ), namely, scans of excellent IQ (n = 53) and lower IQ due to lower levels of arterial enhancement and/or presence of noise (n = 21). The standard of truth was based on the 2 radiologists' consensus reading and the results of CAD. The software detected 80 of 93 peripheral clots present in the 21 patients (42 segmental and 38 subsegmental clots). The overall sensitivity (95% confidence interval) of the CAD tool was 86% (77%-92%) for detecting peripheral clots, 78% (64.5%-88%) at the segmental level and 97% (85.5%-99.9%) at the subsegmental level. Assuming normal vascular anatomy with 20 segmental and 40 subsegmental arteries, overall specificity and positive and negative predictive values (95% confidence interval) of the software were 91.8% (91%-92.6%), 18.4% (15%-22.4%), and 99.7% (99.5%-99.8%), respectively. A mean of 5.4 false positives was found per patient (total, 354 false positives), mainly linked to the presence of perivascular connective tissue (n = 119; 34%) and perivascular airspace consolidation (n = 97; 27%). The sensitivities (95% confidence interval) for the CAD tool were 91% (69.8%-99.3%) for dual-energy, 87% (59.3%-93.2%) for electrocardiography-gated, and 87% (73.5%-95.3%) for nongated scans (P > 0.05). No significant difference was found in the sensitivity of the CAD software when comparing the scans according to the scanning conditions and image quality. The evaluated CAD software has a good sensitivity in detecting peripheral PE, which is not influenced by the scanning conditions or the overall image quality.

An interactive modeling program for the generation of planar polygons for boundary type solids representations of wire frame models

NASA Technical Reports Server (NTRS)

Ozsoy, T.; Ochs, J. B.

1984-01-01

The development of a general link between three dimensional wire frame models and rigid solid models is discussed. An interactive computer graphics program was developed to serve as a front end to an algorithm (COSMIC Program No. ARC-11446) which offers a general solution to the hidden line problem where the input data is either line segments of n-sided planar polygons of the most general type with internal boundaries. The program provides a general interface to CAD/CAM data bases and is implemented for models created on the Unigraphics VAX 11/780-based CAD/CAM systems with the display software written for DEC's VS11 color graphics devices.

CAD-CAM plates versus conventional fixation plates for primary mandibular reconstruction: A biomechanical in vitro analysis.

PubMed

Rendenbach, Carsten; Sellenschloh, Kay; Gerbig, Lucca; Morlock, Michael M; Beck-Broichsitter, Benedicta; Smeets, Ralf; Heiland, Max; Huber, Gerd; Hanken, Henning

2017-11-01

CAD/CAM reconstruction plates have become a viable option for mandible reconstruction. The aim of this study was to determine whether CAD/CAM plates provide higher fatigue strength compared with conventional fixation systems. 1.0 mm miniplates, 2.0 mm conventional locking plates (DePuy Synthes, Umkirch, Germany), and 2.0 mm CAD/CAM plates (Materialise, Leuven, Belgium/DePuy Synthes) were used to reconstruct a polyurethane mandible model (Synbone, Malans, CH) with cortical and cancellous bone equivalents. Mastication was simulated via cyclic dynamic testing using a universal testing machine (MTS, Bionix, Eden Prairie, MN, USA) until material failure reached a rate of 1 Hz with increasing loads on the left side. No significant difference was found between the groups until a load of 300 N. At higher loads, vertical displacement differed increasingly, with a poorer performance of miniplates (p = 0.04). Plate breakage occurred in miniplates and conventional locking plates. Screw breakage was recorded as the primary failure mechanism in CAD/CAM plates. Stiffness was significantly higher with the CAD/CAM plates (p = 0.04). CAD/CAM plates and reconstruction plates provide higher fatigue strength than miniplates, and stiffness is highest in CAD/CAM systems. All tested fixation methods seem sufficiently stable for mandible reconstruction. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Distortion of CAD-CAM-fabricated implant-fixed titanium and zirconia complete dental prosthesis frameworks.

PubMed

Al-Meraikhi, Hadi; Yilmaz, Burak; McGlumphy, Edwin; Brantley, William A; Johnston, William M

2018-01-01

Computer-aided design and computer-aided manufacturing (CAD-CAM)-fabricated titanium and zirconia implant-supported fixed dental prostheses have become increasingly popular for restoring patients with complete edentulism. However, the distortion level of these frameworks is not well known. The purpose of this in vitro study was to compare the 3-dimensional (3D) distortion of CAD-CAM zirconia and titanium implant-fixed screw-retained complete dental prostheses. A master edentulous model with 4 implants at the positions of the maxillary first molars and canines was used. Multiunit abutments (Nobel Biocare) secured to the model were digitally scanned using scan bodies and a laboratory scanner (S600 ARTI; Zirkonzahn). Titanium (n=5) and zirconia (n=5) frameworks were milled using a CAD-CAM system (Zirkonzahn M1; Zirkonzahn). All frameworks were scanned using an industrial computed tomography (CT) scanner (Nikon/X-Tek XT H 225kV MCT Micro-Focus). The direct CT scans were reconstructed to generate standard tessellation language (STL) files. To calculate the 3D distortion of the frameworks, STL files of the CT scans were aligned to the CAD model using a sum of the least squares best-fit algorithm. Surface comparison points were placed on the CAD model on the midfacial aspect of all teeth. The 3D distortion of each direct scan to the CAD model was calculated. In addition, color maps of the scan-to-CAD comparison were constructed using a ±0.500 mm color scale range. Both materials exhibited distortion; however, no significant difference was found in the amount of distortion from the CAD model between the materials (P=.747). Absolute values of deviations from the CAD model were evident in the x and y plane and less so in the z direction. Zirconia and titanium frameworks showed similar 3D distortion compared with the CAD model for the tested CAD-CAM and implant systems. The distortion was more pronounced in the horizontal and sagittal plane than in the vertical plane. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Comparative fracture strength analysis of Lava and Digident CAD/CAM zirconia ceramic crowns.

PubMed

Kwon, Taek-Ka; Pak, Hyun-Soon; Yang, Jae-Ho; Han, Jung-Suk; Lee, Jai-Bong; Kim, Sung-Hun; Yeo, In-Sung

2013-05-01

All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. Twenty Lava CAD/CAM zirconia crowns and twenty Digident CAD/CAM zirconia crowns were fabricated. A metal die was also duplicated from the original prepared tooth for fracture testing. A universal testing machine was used to determine the fracture strength of the crowns. THE MEAN FRACTURE STRENGTHS WERE AS FOLLOWS: 54.9 ± 15.6 N for the Lava CAD/CAM zirconia crowns and 87.0 ± 16.0 N for the Digident CAD/CAM zirconia crowns. The difference between the mean fracture strengths of the Lava and Digident crowns was statistically significant (P<.001). Lava CAD/CAM zirconia crowns showed a complete fracture of both the veneering porcelain and the core whereas the Digident CAD/CAM zirconia crowns showed fracture only of the veneering porcelain. The fracture strengths of CAD/CAM zirconia crowns differ depending on the compatibility of the core material and the veneering porcelain.

Coordinated Research in Robotics and Integrated Manufacturing.

DTIC Science & Technology

1983-07-31

of three research divisions: Robot Systems, Management Systems, and Integrated Design and Manufacturing, and involves about 40 faculty spanning the...keystone of their program. A relatively smaller level of effort is being supported within the Management Systems Division. This is the first annual...SYSTEMS MANAGEMENT 0 DESIGN DATABASES " ROBOT-BASED 0 HUMAN FACTORSMANUFACTURING • CAD CELL* PRODUCTIONMUCR LANNING * INTEGRATION LANGUAGE AND VIA LOCAL

Defeaturing CAD models using a geometry-based size field and facet-based reduction operators.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quadros, William Roshan; Owen, Steven James

2010-04-01

We propose a method to automatically defeature a CAD model by detecting irrelevant features using a geometry-based size field and a method to remove the irrelevant features via facet-based operations on a discrete representation. A discrete B-Rep model is first created by obtaining a faceted representation of the CAD entities. The candidate facet entities are then marked for reduction by using a geometry-based size field. This is accomplished by estimating local mesh sizes based on geometric criteria. If the field value at a facet entity goes below a user specified threshold value then it is identified as an irrelevant featuremore » and is marked for reduction. The reduction of marked facet entities is primarily performed using an edge collapse operator. Care is taken to retain a valid geometry and topology of the discrete model throughout the procedure. The original model is not altered as the defeaturing is performed on a separate discrete model. Associativity between the entities of the discrete model and that of original CAD model is maintained in order to decode the attributes and boundary conditions applied on the original CAD entities onto the mesh via the entities of the discrete model. Example models are presented to illustrate the effectiveness of the proposed approach.« less

Three-dimensional digitizer for the footwear industry

NASA Astrophysics Data System (ADS)

Gonzalez, Francisco; Campoy, Pascual; Aracil, Rafael; Penafiel, Francisco; Sebastian, Jose M.

1993-12-01

This paper presents a developed system for digitizing 3D objects in the footwear industry (e.g. mould, soles, heels) and their introduction in a CAD system for further manipulation and production of rapid prototypes. The system is based on the acquisition of the sequence of images of the projection of a laser line onto the 3D object when this is moving in front of the laser beam and the camera. This beam projection lights a 3D curve on the surface of the object, whose image is processed in order to obtain the 3D coordinates of every point of mentioned curve according to a previous calibration of the system. These coordinates of points in all the curves are analyzed and combined in order to make up a 3D wire-frame model of the object, which is introduced in a CAD station for further design and connection to the machinery for rapid prototyping.

A rule based computer aided design system

NASA Technical Reports Server (NTRS)

Premack, T.

1986-01-01

A Computer Aided Design (CAD) system is presented which supports the iterative process of design, the dimensional continuity between mating parts, and the hierarchical structure of the parts in their assembled configuration. Prolog, an interactive logic programming language, is used to represent and interpret the data base. The solid geometry representing the parts is defined in parameterized form using the swept volume method. The system is demonstrated with a design of a spring piston.

Atherosclerosis as a disease of failed endogenous repair

PubMed Central

Zenovich, Andrey G.; Taylor, Doris A.

2009-01-01

As coronary artery disease (CAD) continues to be the primary cause of mortality, a more in-depth understanding of pathophysiology and novel treatments are being sought. The past two decades have established inflammation as a driving force behind CAD – from endothelial dysfunction to heart failure. Recent advances in stem/progenitor cell biology have led to initial applications of progenitor cells in CAD continuum and have revealed that atherosclerosis is, at least in part, a disease of failed endogenous vascular repair. Several key progenitor cell populations including endothelial progenitor cells (AC133+/CD34+ population), vascular progenitors (CD31+/CD45low population), KDR+ cells and other bone marrow subtypes are mobilized for vascular repair. However, age and risk factors negatively impact these cells even prior to clinical CAD. Sex-based differences in progenitor cell capacity for repair have emerged as a new research focus that may offer mechanistic insights into clinical CAD discrepancies between men and women. Quantifying injury and cell-based repair and better defining their interactions should enable us to halt or even prevent CAD by enhancing the repair side of the repair/injury equation. PMID:18508460

Optimized multi-level elongated quinary patterns for the assessment of thyroid nodules in ultrasound images.

PubMed

Raghavendra, U; Gudigar, Anjan; Maithri, M; Gertych, Arkadiusz; Meiburger, Kristen M; Yeong, Chai Hong; Madla, Chakri; Kongmebhol, Pailin; Molinari, Filippo; Ng, Kwan Hoong; Acharya, U Rajendra

2018-04-01

Ultrasound imaging is one of the most common visualizing tools used by radiologists to identify the location of thyroid nodules. However, visual assessment of nodules is difficult and often affected by inter- and intra-observer variabilities. Thus, a computer-aided diagnosis (CAD) system can be helpful to cross-verify the severity of nodules. This paper proposes a new CAD system to characterize thyroid nodules using optimized multi-level elongated quinary patterns. In this study, higher order spectral (HOS) entropy features extracted from these patterns appropriately distinguished benign and malignant nodules under particle swarm optimization (PSO) and support vector machine (SVM) frameworks. Our CAD algorithm achieved a maximum accuracy of 97.71% and 97.01% in private and public datasets respectively. The evaluation of this CAD system on both private and public datasets confirmed its effectiveness as a secondary tool in assisting radiological findings. Copyright © 2018 Elsevier Ltd. All rights reserved.

Learning-based image preprocessing for robust computer-aided detection

NASA Astrophysics Data System (ADS)

Raghupathi, Laks; Devarakota, Pandu R.; Wolf, Matthias

2013-03-01

Recent studies have shown that low dose computed tomography (LDCT) can be an effective screening tool to reduce lung cancer mortality. Computer-aided detection (CAD) would be a beneficial second reader for radiologists in such cases. Studies demonstrate that while iterative reconstructions (IR) improve LDCT diagnostic quality, it however degrades CAD performance significantly (increased false positives) when applied directly. For improving CAD performance, solutions such as retraining with newer data or applying a standard preprocessing technique may not be suffice due to high prevalence of CT scanners and non-uniform acquisition protocols. Here, we present a learning-based framework that can adaptively transform a wide variety of input data to boost an existing CAD performance. This not only enhances their robustness but also their applicability in clinical workflows. Our solution consists of applying a suitable pre-processing filter automatically on the given image based on its characteristics. This requires the preparation of ground truth (GT) of choosing an appropriate filter resulting in improved CAD performance. Accordingly, we propose an efficient consolidation process with a novel metric. Using key anatomical landmarks, we then derive consistent feature descriptors for the classification scheme that then uses a priority mechanism to automatically choose an optimal preprocessing filter. We demonstrate CAD prototype∗ performance improvement using hospital-scale datasets acquired from North America, Europe and Asia. Though we demonstrated our results for a lung nodule CAD, this scheme is straightforward to extend to other post-processing tools dedicated to other organs and modalities.

The effect of milling and postmilling procedures on the surface roughness of CAD/CAM materials.

PubMed

Mota, Eduardo Gonçalves; Smidt, Laura Nunes; Fracasso, Lisiane Martins; Burnett, Luiz Henrique; Spohr, Ana Maria

2017-11-12

The aim of this study was to evaluate the surface roughness and analyze the surface topography of five different CAD/CAM ceramics and one CAD/CAM composite resin for CEREC after milling and postmilling procedures. Blocks of the ceramics Mark II, IPS Empress CAD, IPS e.max CAD, Suprinity and Enamic, and blocks of the composite resin Lava Ultimate were milled at CEREC MCXL. Ten flat samples of each material were obtained. The surface roughness (Ra) test was performed before and after milling, crystallization, polishing, and glaze when indicated, followed by SEM and AFM analysis. Data were submitted to one-way ANOVA with repeated measures and the Tukey HSD test (α = 0.05). The milling step significantly increased the roughness of all the tested materials (P < .05). Lithium-based ceramics (IPS e.max CAD and Suprinity) were more suitable to roughness than the other tested materials (P < .05). The polishing methods were able to reduce roughness to baseline values, except for lithium-based ceramics. Glaze reduced significantly the roughness of lithium-based ceramics without a difference from the baseline. SEM and AFM images revealed that glazed surfaces are smoother than polished surfaces. All hard-milling CAD/CAM materials, that is, fully sintered, should be only hand polished. The glaze step can be suppressed resulting in time saving. However, the glaze step in soft-milling lithium disilicate is imperative. © 2017 Wiley Periodicals, Inc.

Structural and Functional Analysis of the Signal-Transducing Linker in the pH-Responsive One-Component System CadC of Escherichia coli.

PubMed

Buchner, Sophie; Schlundt, Andreas; Lassak, Jürgen; Sattler, Michael; Jung, Kirsten

2015-07-31

The pH-responsive one-component signaling system CadC in Escherichia coli belongs to the family of ToxR-like proteins, whose members share a conserved modular structure, with an N-terminal cytoplasmic winged helix-turn-helix DNA-binding domain being followed by a single transmembrane helix and a C-terminal periplasmic pH-sensing domain. In E. coli CadC, a cytoplasmic linker comprising approximately 50 amino acids is essential for transmission of the signal from the sensor to the DNA-binding domain. However, the mechanism of transduction is poorly understood. Using NMR spectroscopy, we demonstrate here that the linker region is intrinsically disordered in solution. Furthermore, mutational analyses showed that it tolerates a range of amino acid substitutions (altering polarity, rigidity and α-helix-forming propensity), is robust to extension but is sensitive to truncation. Indeed, truncations either reversed the expression profile of the target operon cadBA or decoupled expression from external pH altogether. CadC dimerizes via its periplasmic domain, but light-scattering analysis provided no evidence for dimerization of the isolated DNA-binding domain, with or without the linker region. However, bacterial two-hybrid analysis revealed that CadC forms stable dimers in a stimulus- and linker-dependent manner, interacting only at pH<6.8. Strikingly, a variant with inversed cadBA expression profile, which lacks most of the linker, dimerizes preferentially at higher pH. Thus, we propose that the disordered CadC linker is required for transducing the pH-dependent response of the periplasmic sensor into a structural rearrangement that facilitates dimerization of the cytoplasmic CadC DNA-binding domain. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bond strength of novel CAD/CAM restorative materials to self-adhesive resin cement: the effect of surface treatments.

PubMed

Elsaka, Shaymaa E

2014-12-01

To evaluate the effect of different surface treatments on the microtensile bond strength (μTBS) of novel CAD/CAM restorative materials to self-adhesive resin cement. Two types of CAD/CAM restorative materials (Vita Enamic [VE] and Lava Ultimate [LU]) were used. The specimens were divided into five groups in each test according to the surface treatment performed; Gr 1 (control; no treatment), Gr 2 (sandblasted [SB]), Gr 3 (SB+silane [S]), Gr 4 (hydrofluoric acid [HF]), and Gr 5 (HF+S). A dual-curing self-adhesive resin cement (Bifix SE [BF]) was applied to each group for testing the adhesion after 24 h of storage in distilled water or after 30 days using the μTBS test. Following fracture testing, specimens were examined with a stereomicroscope and SEM. Surface roughness and morphology of the CAD/CAM restorative materials were characterized after treatment. Data were analyzed using ANOVA and Tukey's test. The surface treatment, type of CAD/CAM restorative material, and water storage periods showed a significant effect on the μTBS (p<0.001). For the LU/BF system, there was no significant difference in the bond strength values between different surface treatments (p>0.05). On the other hand, for the VE/BF system, surface treatment with HF+S showed higher bond strength values compared with SB and HF surface treatments (p<0.05). Surface roughness and SEM analyses showed that the surface topography of CAD/CAM restorative materials was modified after treatments. The effect of surface treatments on the bond strength of novel CAD/CAM restorative materials to resin cement is material dependent. The VE/BF CAD/CAM material provided higher bond strength values compared with the LU/BF CAD/CAM material.

Project Integration Architecture (PIA) and Computational Analysis Programming Interface (CAPRI) for Accessing Geometry Data from CAD Files

NASA Technical Reports Server (NTRS)

Benyo, Theresa L.

2002-01-01

Integration of a supersonic inlet simulation with a computer aided design (CAD) system is demonstrated. The integration is performed using the Project Integration Architecture (PIA). PIA provides a common environment for wrapping many types of applications. Accessing geometry data from CAD files is accomplished by incorporating appropriate function calls from the Computational Analysis Programming Interface (CAPRI). CAPRI is a CAD vendor neutral programming interface that aids in acquiring geometry data directly from CAD files. The benefits of wrapping a supersonic inlet simulation into PIA using CAPRI are; direct access of geometry data, accurate capture of geometry data, automatic conversion of data units, CAD vendor neutral operation, and on-line interactive history capture. This paper describes the PIA and the CAPRI wrapper and details the supersonic inlet simulation demonstration.

Association of N-terminal pro-brain natriuretic peptide with the severity of coronary artery disease in patients with normal left ventricular ejection fraction.

PubMed

Wu, Naqiong; Ma, Fenglian; Guo, Yuanlin; Li, Xiaoling; Liu, Jun; Qing, Ping; Xu, Ruixia; Zhu, Chenggang; Jia, Yanjun; Liu, Geng; Dong, Qian; Jiang, Lixin; Li, Jianjun

2014-01-01

Backround N-terminal pro-brain natriuretic peptide (NT-proBNP) is a reliable predictor in acute coronary artery disease (CAD). Little is known about patients with stable CAD, especially Chinese patients with CAD. The aim of the present study was to investigate the association of NT-proBNP levels with the severity of CAD in patients with normal left ventricular ejection fraction. A total of 658 consecutive patients were divided into two groups based on angiograms: CAD group (n = 484) and angiographic normal control group (n = 174). The severity of CAD was evaluated by modified Gensini score, and its relationship with NT-proBNP was analyzed. The prevalence of risk factors such as age, male gender, diabetes mellitus (DM), dyslipidemia, smoking, and family history of CAD in the CAD group were higher than that in the control group. In multivariate regression model analysis, age, gender, and DM were determinants of the presence of CAD. NT-pro BNP was found to be an independent predictor for CAD (OR:1.66 (95% CI: 1.06-2.61), P < 0.05). In a receiver operating characteristic (ROC) curve analysis, an NT-proBNP value of 641.15 pmol/L was identified as a cut-off value in the diagnosis or exclusion of CAD (area under curve (AUC) = 0.56, 95% CI: 0.51-0.61). Furthermore, NT-proBNP was positively correlated with Gensini score (r = 0.14, P < 0.001) in patients with CAD. NT-proBNP was an independent predictor for Chinese patients with CAD, suggesting that the NT-proBNP level might be associated with the presence and the severity of CAD.

A novel aromatic alcohol dehydrogenase in higher plants: molecular cloning and expression.

PubMed

Goffner, D; Van Doorsselaere, J; Yahiaoui, N; Samaj, J; Grima-Pettenati, J; Boudet, A M

1998-03-01

Cinnamyl alcohol dehydrogenase (CAD; EC 1.1.195) catalyses the conversion of p-hydroxy-cinnamaldehydes to the corresponding alcohols and is considered a key enzyme in lignin biosynthesis. In a previous study, an atypical form of CAD (CAD 1) was identified in Eucalyptus gunnii [12]. We report here the molecular cloning and characterization of the corresponding cDNA, CAD 1-5, which encodes this novel aromatic alcohol dehydrogenase. The identity of CAD 1-5 was unambiguously confirmed by sequence comparison of the cDNA with peptide sequences derived from purified CAD 1 protein and by functional expression of CAD 1 recombinant protein in Escherichia coli. Both native and recombinant CAD 1 exhibit high affinity towards lignin precursors including 4-coumaraldehyde and coniferaldehyde, but they do not accept sinapaldehyde. Moreover, recombinant CAD 1 can also utilize a wide range of aromatic substrates including unsubstituted and substituted benzaldehydes. The open reading frame of CAD 1-5 encodes a protein with a calculated molecular mass of 35,790 Da and an isoelectric point of 8.1. Although sequence comparisons with proteins in databases revealed significant similarities with dihydroflavonol-4-reductases (DFR; EC 1.1.1.219) from a wide range of plant species, the most striking similarity was found with cinnamoyl-CoA reductase (CCR; EC 1.2.1.44), the enzyme which directly precedes CAD in the lignin biosynthetic pathway. RNA blot analysis and immunolocalization experiments indicated that CAD 1 is expressed in both lignified and unlignified tissues/cells. Based on the catalytic activity of CAD 1 in vitro and its localization in planta, CAD 1 may function as an 'alternative' enzyme in the lignin biosynthetic pathway. However, additional roles in phenolic metabolism are not excluded.

Computer aided detection of surgical retained foreign object for prevention

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadjiiski, Lubomir, E-mail: lhadjisk@umich.edu; Marentis, Theodore C.; Rondon, Lucas

2015-03-15

Purpose: Surgical retained foreign objects (RFOs) have significant morbidity and mortality. They are associated with approximately $1.5 × 10{sup 9} annually in preventable medical costs. The detection accuracy of radiographs for RFOs is a mediocre 59%. The authors address the RFO problem with two complementary technologies: a three-dimensional (3D) gossypiboma micro tag, the μTag that improves the visibility of RFOs on radiographs, and a computer aided detection (CAD) system that detects the μTag. It is desirable for the CAD system to operate in a high specificity mode in the operating room (OR) and function as a first reader for themore » surgeon. This allows for fast point of care results and seamless workflow integration. The CAD system can also operate in a high sensitivity mode as a second reader for the radiologist to ensure the highest possible detection accuracy. Methods: The 3D geometry of the μTag produces a similar two dimensional (2D) depiction on radiographs regardless of its orientation in the human body and ensures accurate detection by a radiologist and the CAD. The authors created a data set of 1800 cadaver images with the 3D μTag and other common man-made surgical objects positioned randomly. A total of 1061 cadaver images contained a single μTag and the remaining 739 were without μTag. A radiologist marked the location of the μTag using an in-house developed graphical user interface. The data set was partitioned into three independent subsets: a training set, a validation set, and a test set, consisting of 540, 560, and 700 images, respectively. A CAD system with modules that included preprocessing μTag enhancement, labeling, segmentation, feature analysis, classification, and detection was developed. The CAD system was developed using the training and the validation sets. Results: On the training set, the CAD achieved 81.5% sensitivity with 0.014 false positives (FPs) per image in a high specificity mode for the surgeons in the OR and 96.1% sensitivity with 0.81 FPs per image in a high sensitivity mode for the radiologists. On the independent test set, the CAD achieved 79.5% sensitivity with 0.003 FPs per image in a high specificity mode for the surgeons and 90.2% sensitivity with 0.23 FPs per image in a high sensitivity mode for the radiologists. Conclusions: To the best of the authors’ knowledge, this is the first time a 3D μTag is used to produce a recognizable, substantially similar 2D projection on radiographs regardless of orientation in space. It is the first time a CAD system is used to search for man-made objects over anatomic background. The CAD system for the μTags achieved reasonable performance in both the high specificity and the high sensitivity modes.« less

Analysis, synchronisation and circuit design of a new highly nonlinear chaotic system

NASA Astrophysics Data System (ADS)

Mobayen, Saleh; Kingni, Sifeu Takougang; Pham, Viet-Thanh; Nazarimehr, Fahimeh; Jafari, Sajad

2018-02-01

This paper investigates a three-dimensional autonomous chaotic flow without linear terms. Dynamical behaviour of the proposed system is investigated through eigenvalue structures, phase portraits, bifurcation diagram, Lyapunov exponents and basin of attraction. For a suitable choice of the parameters, the proposed system can exhibit anti-monotonicity, periodic oscillations and double-scroll chaotic attractor. Basin of attraction of the proposed system shows that the chaotic attractor is self-excited. Furthermore, feasibility of double-scroll chaotic attractor in the real word is investigated by using the OrCAD-PSpice software via an electronic implementation of the proposed system. A good qualitative agreement is illustrated between the numerical simulations and the OrCAD-PSpice results. Finally, a finite-time control method based on dynamic sliding surface for the synchronisation of master and slave chaotic systems in the presence of external disturbances is performed. Using the suggested control technique, the superior master-slave synchronisation is attained. Illustrative simulation results on the studied chaotic system are presented to indicate the effectiveness of the suggested scheme.

Incorporation of CAD/CAM Restoration Into Navy Dentistry

DTIC Science & Technology

2017-09-26

CAD/CAM Computer-aided design /Computer-assisted manufacturing CDT Common Dental Terminology DENCAS Dental Common Access System DTF Dental...to reduce avoidable dental emergencies for deployed sailors and marines. Dental Computer-aided design /Computer-assisted manufacturing (CAD/CAM...report will review and evaluate the placement rate by Navy dentists of digitally fabricated in-office ceramic restorations compared to traditional direct

Nonobstructive coronary artery disease and risk of myocardial infarction.

PubMed

Maddox, Thomas M; Stanislawski, Maggie A; Grunwald, Gary K; Bradley, Steven M; Ho, P Michael; Tsai, Thomas T; Patel, Manesh R; Sandhu, Amneet; Valle, Javier; Magid, David J; Leon, Benjamin; Bhatt, Deepak L; Fihn, Stephan D; Rumsfeld, John S

2014-11-05

Little is known about cardiac adverse events among patients with nonobstructive coronary artery disease (CAD). To compare myocardial infarction (MI) and mortality rates between patients with nonobstructive CAD, obstructive CAD, and no apparent CAD in a national cohort. Retrospective cohort study of all US veterans undergoing elective coronary angiography for CAD between October 2007 and September 2012 in the Veterans Affairs health care system. Patients with prior CAD events were excluded. Angiographic CAD extent, defined by degree (no apparent CAD: no stenosis >20%; nonobstructive CAD: ≥1 stenosis ≥20% but no stenosis ≥70%; obstructive CAD: any stenosis ≥70% or left main [LM] stenosis ≥50%) and distribution (1, 2, or 3 vessel). The primary outcome was 1-year hospitalization for nonfatal MI after the index angiography. Secondary outcomes included 1-year all-cause mortality and combined 1-year MI and mortality. Among 37,674 patients, 8384 patients (22.3%) had nonobstructive CAD and 20,899 patients (55.4%) had obstructive CAD. Within 1 year, 845 patients died and 385 were rehospitalized for MI. Among patients with no apparent CAD, the 1-year MI rate was 0.11% (n = 8, 95% CI, 0.10%-0.20%) and increased progressively by 1-vessel nonobstructive CAD, 0.24% (n = 10, 95% CI, 0.10%-0.40%); 2-vessel nonobstructive CAD, 0.56% (n = 13, 95% CI, 0.30%-1.00%); 3-vessel nonobstructive CAD, 0.59% (n = 6, 95% CI, 0.30%-1.30%); 1-vessel obstructive CAD, 1.18% (n = 101, 95% CI, 1.00%-1.40%); 2-vessel obstructive CAD, 2.18% (n = 110, 95% CI, 1.80%-2.60%); and 3-vessel or LM obstructive CAD, 2.47% (n = 137, 95% CI, 2.10%-2.90%). After adjustment, 1-year MI rates increased with increasing CAD extent. Relative to patients with no apparent CAD, patients with 1-vessel nonobstructive CAD had a hazard ratio (HR) for 1-year MI of 2.0 (95% CI, 0.8-5.1); 2-vessel nonobstructive HR, 4.6 (95% CI, 2.0-10.5); 3-vessel nonobstructive HR, 4.5 (95% CI, 1.6-12.5); 1-vessel obstructive HR, 9.0 (95% CI, 4.2-19.0); 2-vessel obstructive HR, 16.5 (95% CI, 8.1-33.7); and 3-vessel or LM obstructive HR, 19.5 (95% CI, 9.9-38.2). One-year mortality rates were associated with increasing CAD extent, ranging from 1.38% among patients without apparent CAD to 4.30% with 3-vessel or LM obstructive CAD. After risk adjustment, there was no significant association between 1- or 2-vessel nonobstructive CAD and mortality, but there were significant associations with mortality for 3-vessel nonobstructive CAD (HR, 1.6; 95% CI, 1.1-2.5), 1-vessel obstructive CAD (HR, 1.9; 95% CI, 1.4-2.6), 2-vessel obstructive CAD (HR, 2.8; 95% CI, 2.1-3.7), and 3-vessel or LM obstructive CAD (HR, 3.4; 95% CI, 2.6-4.4). Similar associations were noted with the combined outcome. In this cohort of patients undergoing elective coronary angiography, nonobstructive CAD, compared with no apparent CAD, was associated with a significantly greater 1-year risk of MI and all-cause mortality. These findings suggest clinical importance of nonobstructive CAD and warrant further investigation of interventions to improve outcomes among these patients.

Design of Complete Dentures by Adopting CAD Developed for Fixed Prostheses.

PubMed

Li, Yanfeng; Han, Weili; Cao, Jing; Iv, Yuan; Zhang, Yue; Han, Yishi; Shen, Yi; Ma, Zheng; Liu, Huanyue

2018-02-01

The demand for complete dentures is expected to increase worldwide, but complete dentures are mainly designed and fabricated manually involving a broad series of clinical and laboratory procedures. Therefore, the quality of complete dentures largely depends on the skills of the dentist and technician, leading to difficulty in quality control. Computer-aided design and manufacturing (CAD/CAM) has been used to design and fabricate various dental restorations including dental inlays, veneers, crowns, partial crowns, and fixed partial dentures (FPDs). It has been envisioned that the application of CAD/CAM technology could reduce intensive clinical/laboratory work for the fabrication of complete dentures; however, CAD/CAM is seldom used to fabricate complete dentures due to the lack of suitable CAD software to design virtual complete dentures although the CAM techniques are in a much advanced stage. Here we report the successful design of virtual complete dentures using CAD software of 3Shape Dental System 2012, which was developed for designing fixed prostheses instead of complete dentures. Our results demonstrated that complete dentures could be successfully designed by the combination of two modeling processes, single coping and full anatomical FPD, available in the 3Shape Dental System 2012. © 2016 by the American College of Prosthodontists.

Computer-Aided-Design of the Hydraulic System of Three-Dimensional Cartridge Valve Blocks (Selected Articles)

DTIC Science & Technology

1991-03-21

sectional representation of the spatial figure can be correctly determined. 6 The AutoLisp language system in the AutoCAD software provides the most...softwares are developed on the 32-bit machines and little progress has been reported for the 16-bit machines. Even the AutoCAD is a two-ard-a-half... AutoCAD software as the basis, developed the design package of 3-D cartridge valve blocks on IM PC/AT. To realize the 3-D displaying of cartridge valves

Monolithic and bi-layer CAD/CAM lithium-disilicate versus metal-ceramic fixed dental prostheses: comparison of fracture loads and failure modes after fatigue.

PubMed

Schultheis, Stefan; Strub, Joerg R; Gerds, Thomas A; Guess, Petra C

2013-06-01

The authors analyzed the effect of fatigue on the survival rate and fracture load of monolithic and bi-layer CAD/CAM lithium-disilicate posterior three-unit fixed dental prostheses (FDPs) in comparison to the metal-ceramic gold standard. The authors divided 96 human premolars and molars into three equal groups. Lithium-disilicate ceramic (IPS-e.max-CAD) was milled with the CEREC-3-system in full-anatomic FDP dimensions (monolithic: M-LiCAD) or as framework (Bi-layer: BL-LiCAD) with subsequent hand-layer veneering. Metal-ceramic FDPs (MC) served as control. Single-load-to-failure tests were performed before and after mouth-motion fatigue. No fracture failures occurred during fatigue. Median fracture loads in [N], before and after fatigue were, respectively, as follows: M-LiCAD, 1,298/1,900; BL-LiCAD, 817/699; MC, 1,966/1,818. M-LiCAD and MC FPDs revealed comparable fracture loads and were both significantly higher than BL-LiCAD. M-LiCAD and BL-LiCAD both failed from core/veneer bulk fracture within the connector area. MC failures were limited to ceramic veneer fractures exposing the metal core. Fatigue had no significant effect on any group. Posterior monolithic CAD/CAM fabricated lithium-disilicate FPDs were shown to be fracture resistant with failure load results comparable to the metal-ceramic gold standard. Clinical investigations are needed to confirm these promising laboratory results. Monolithic CAD/CAM fabricated lithium-disilicate FDPs appeared to be a reliable treatment alternative for the posterior load-bearing area, whereas FDPs in bi-layer configuration were susceptible to low load fracture failure.

Elevated Glucose Oxidation, Reduced Insulin Secretion, and a Fatty Heart May Be Protective Adaptions in Ischemic CAD.

PubMed

Hannukainen, J C; Lautamäki, R; Mari, A; Pärkkä, J P; Bucci, M; Guzzardi, M A; Kajander, S; Tuokkola, T; Knuuti, J; Iozzo, P

2016-07-01

Insulin resistance, β-cell dysfunction, and ectopic fat deposition have been implicated in the pathogenesis of coronary artery disease (CAD) and type 2 diabetes, which is common in CAD patients. We investigated whether CAD is an independent predictor of these metabolic abnormalities and whether this interaction is influenced by superimposed myocardial ischemia. We studied CAD patients with (n = 8) and without (n = 14) myocardial ischemia and eight non-CAD controls. Insulin sensitivity and secretion and substrate oxidation were measured during fasting and oral glucose tolerance testing. We used magnetic resonance imaging/spectroscopy, positron emission and computerized tomography to characterize CAD, cardiac function, pericardial and abdominal adipose tissue, and myocardial, liver, and pancreatic triglyceride contents. Ischemic CAD was characterized by elevated oxidative glucose metabolism and a proportional decline in β-cell insulin secretion and reduction in lipid oxidation. Cardiac function was preserved in CAD groups, whereas cardiac fat depots were elevated in ischemic CAD compared to non-CAD subjects. Liver and pancreatic fat contents were similar in all groups and related with surrounding adipose masses or systemic insulin sensitivity. In ischemic CAD patients, glucose oxidation is enhanced and correlates inversely with insulin secretion. This can be seen as a mechanism to prevent glucose lowering because glucose is required in oxygen-deprived tissues. On the other hand, the accumulation of cardiac triglycerides may be a physiological adaptation to the limited fatty acid oxidative capacity. Our results underscore the urgent need of clinical trials that define the optimal/safest glycemic range in situations of myocardial ischemia.

Elevated Glucose Oxidation, Reduced Insulin Secretion, and a Fatty Heart May Be Protective Adaptions in Ischemic CAD

PubMed Central

Hannukainen, J. C.; Lautamäki, R.; Mari, A.; Pärkkä, J. P.; Bucci, M.; Guzzardi, M. A.; Kajander, S.; Tuokkola, T.; Knuuti, J.

2016-01-01

Background: Insulin resistance, β-cell dysfunction, and ectopic fat deposition have been implicated in the pathogenesis of coronary artery disease (CAD) and type 2 diabetes, which is common in CAD patients. We investigated whether CAD is an independent predictor of these metabolic abnormalities and whether this interaction is influenced by superimposed myocardial ischemia. Methods and Results: We studied CAD patients with (n = 8) and without (n = 14) myocardial ischemia and eight non-CAD controls. Insulin sensitivity and secretion and substrate oxidation were measured during fasting and oral glucose tolerance testing. We used magnetic resonance imaging/spectroscopy, positron emission and computerized tomography to characterize CAD, cardiac function, pericardial and abdominal adipose tissue, and myocardial, liver, and pancreatic triglyceride contents. Ischemic CAD was characterized by elevated oxidative glucose metabolism and a proportional decline in β-cell insulin secretion and reduction in lipid oxidation. Cardiac function was preserved in CAD groups, whereas cardiac fat depots were elevated in ischemic CAD compared to non-CAD subjects. Liver and pancreatic fat contents were similar in all groups and related with surrounding adipose masses or systemic insulin sensitivity. Conclusions: In ischemic CAD patients, glucose oxidation is enhanced and correlates inversely with insulin secretion. This can be seen as a mechanism to prevent glucose lowering because glucose is required in oxygen-deprived tissues. On the other hand, the accumulation of cardiac triglycerides may be a physiological adaptation to the limited fatty acid oxidative capacity. Our results underscore the urgent need of clinical trials that define the optimal/safest glycemic range in situations of myocardial ischemia. PMID:27045985

An automation of design and modelling tasks in NX Siemens environment with original software - generator module

NASA Astrophysics Data System (ADS)

Zbiciak, M.; Grabowik, C.; Janik, W.

2015-11-01

Nowadays the design constructional process is almost exclusively aided with CAD/CAE/CAM systems. It is evaluated that nearly 80% of design activities have a routine nature. These design routine tasks are highly susceptible to automation. Design automation is usually made with API tools which allow building original software responsible for adding different engineering activities. In this paper the original software worked out in order to automate engineering tasks at the stage of a product geometrical shape design is presented. The elaborated software works exclusively in NX Siemens CAD/CAM/CAE environment and was prepared in Microsoft Visual Studio with application of the .NET technology and NX SNAP library. The software functionality allows designing and modelling of spur and helicoidal involute gears. Moreover, it is possible to estimate relative manufacturing costs. With the Generator module it is possible to design and model both standard and non-standard gear wheels. The main advantage of the model generated in such a way is its better representation of an involute curve in comparison to those which are drawn in specialized standard CAD systems tools. It comes from fact that usually in CAD systems an involute curve is drawn by 3 points that respond to points located on the addendum circle, the reference diameter of a gear and the base circle respectively. In the Generator module the involute curve is drawn by 11 involute points which are located on and upper the base and the addendum circles therefore 3D gear wheels models are highly accurate. Application of the Generator module makes the modelling process very rapid so that the gear wheel modelling time is reduced to several seconds. During the conducted research the analysis of differences between standard 3 points and 11 points involutes was made. The results and conclusions drawn upon analysis are shown in details.

GPU-accelerated depth map generation for X-ray simulations of complex CAD geometries

NASA Astrophysics Data System (ADS)

Grandin, Robert J.; Young, Gavin; Holland, Stephen D.; Krishnamurthy, Adarsh

2018-04-01

Interactive x-ray simulations of complex computer-aided design (CAD) models can provide valuable insights for better interpretation of the defect signatures such as porosity from x-ray CT images. Generating the depth map along a particular direction for the given CAD geometry is the most compute-intensive step in x-ray simulations. We have developed a GPU-accelerated method for real-time generation of depth maps of complex CAD geometries. We preprocess complex components designed using commercial CAD systems using a custom CAD module and convert them into a fine user-defined surface tessellation. Our CAD module can be used by different simulators as well as handle complex geometries, including those that arise from complex castings and composite structures. We then make use of a parallel algorithm that runs on a graphics processing unit (GPU) to convert the finely-tessellated CAD model to a voxelized representation. The voxelized representation can enable heterogeneous modeling of the volume enclosed by the CAD model by assigning heterogeneous material properties in specific regions. The depth maps are generated from this voxelized representation with the help of a GPU-accelerated ray-casting algorithm. The GPU-accelerated ray-casting method enables interactive (> 60 frames-per-second) generation of the depth maps of complex CAD geometries. This enables arbitrarily rotation and slicing of the CAD model, leading to better interpretation of the x-ray images by the user. In addition, the depth maps can be used to aid directly in CT reconstruction algorithms.

A prostate CAD system based on multiparametric analysis of DCE T1-w, and DW automatically registered images

NASA Astrophysics Data System (ADS)

Giannini, Valentina; Vignati, Anna; Mazzetti, Simone; De Luca, Massimo; Bracco, Christian; Stasi, Michele; Russo, Filippo; Armando, Enrico; Regge, Daniele

2013-02-01

Prostate specific antigen (PSA)-based screening reduces the rate of death from prostate cancer (PCa) by 31%, but this benefit is associated with a high risk of overdiagnosis and overtreatment. As prostate transrectal ultrasound-guided biopsy, the standard procedure for prostate histological sampling, has a sensitivity of 77% with a considerable false-negative rate, more accurate methods need to be found to detect or rule out significant disease. Prostate magnetic resonance imaging has the potential to improve the specificity of PSA-based screening scenarios as a non-invasive detection tool, in particular exploiting the combination of anatomical and functional information in a multiparametric framework. The purpose of this study was to describe a computer aided diagnosis (CAD) method that automatically produces a malignancy likelihood map by combining information from dynamic contrast enhanced MR images and diffusion weighted images. The CAD system consists of multiple sequential stages, from a preliminary registration of images of different sequences, in order to correct for susceptibility deformation and/or movement artifacts, to a Bayesian classifier, which fused all the extracted features into a probability map. The promising results (AUROC=0.87) should be validated on a larger dataset, but they suggest that the discrimination on a voxel basis between benign and malignant tissues is feasible with good performances. This method can be of benefit to improve the diagnostic accuracy of the radiologist, reduce reader variability and speed up the reading time, automatically highlighting probably cancer suspicious regions.

HDL subfractions and very early CAD: novel findings from untreated patients in a Chinese cohort.

PubMed

Zhang, Yan; Zhu, Cheng-Gang; Xu, Rui-Xia; Li, Sha; Li, Xiao-Lin; Guo, Yuan-Lin; Wu, Na-Qiong; Gao, Ying; Qing, Ping; Cui, Chuan-Jue; Sun, Jing; Li, Jian-Jun

2016-08-04

Coronary artery disease (CAD) in very young individuals is a rare disease associated with poor prognosis. However, the role of specific lipoprotein subfractions in very young CAD patients (≤45 years) is not established yet. A total of 734 consecutive CAD subjects were enrolled and were classified as very early (n = 81, ≤45), early (n = 304, male: 45-55; female: 45-65), and late (n = 349, male: >55; female: >65) groups. Meanwhile, a group of non-CAD subjects were also enrolled as controls (n = 56, ≤45). The lipoprotein separation was performed using Lipoprint System. As a result, the very early CAD patients have lower large high-density lipoprotein (HDL) subfraction and higher small low-density lipoprotein (LDL) subfraction (p < 0.05). Although body mass index was inversely related to large HDL subfraction, overweight did not influence its association with very early CAD. In the logistic regression analysis, large HDL was inversely [OR 95% CI: 0.872 (0.825-0.922)] while small LDL was positively [1.038 (1.008-1.069)] related to very early CAD. However, after adjusting potential confounders, the association was only significant for large HDL [0.899 (0.848-0.954)]. This study firstly demonstrated that large HDL subfraction was negatively related to very early CAD suggestive of its important role in very early CAD incidence.

A framework for development of an intelligent system for design and manufacturing of stamping dies

NASA Astrophysics Data System (ADS)

Hussein, H. M. A.; Kumar, S.

2014-07-01

An integration of computer aided design (CAD), computer aided process planning (CAPP) and computer aided manufacturing (CAM) is required for development of an intelligent system to design and manufacture stamping dies in sheet metal industries. In this paper, a framework for development of an intelligent system for design and manufacturing of stamping dies is proposed. In the proposed framework, the intelligent system is structured in form of various expert system modules for different activities of design and manufacturing of dies. All system modules are integrated with each other. The proposed system takes its input in form of a CAD file of sheet metal part, and then system modules automate all tasks related to design and manufacturing of stamping dies. Modules are coded using Visual Basic (VB) and developed on the platform of AutoCAD software.

Enhancing image classification models with multi-modal biomarkers

NASA Astrophysics Data System (ADS)

Caban, Jesus J.; Liao, David; Yao, Jianhua; Mollura, Daniel J.; Gochuico, Bernadette; Yoo, Terry

2011-03-01

Currently, most computer-aided diagnosis (CAD) systems rely on image analysis and statistical models to diagnose, quantify, and monitor the progression of a particular disease. In general, CAD systems have proven to be effective at providing quantitative measurements and assisting physicians during the decision-making process. As the need for more flexible and effective CADs continues to grow, questions about how to enhance their accuracy have surged. In this paper, we show how statistical image models can be augmented with multi-modal physiological values to create more robust, stable, and accurate CAD systems. In particular, this paper demonstrates how highly correlated blood and EKG features can be treated as biomarkers and used to enhance image classification models designed to automatically score subjects with pulmonary fibrosis. In our results, a 3-5% improvement was observed when comparing the accuracy of CADs that use multi-modal biomarkers with those that only used image features. Our results show that lab values such as Erythrocyte Sedimentation Rate and Fibrinogen, as well as EKG measurements such as QRS and I:40, are statistically significant and can provide valuable insights about the severity of the pulmonary fibrosis disease.

Listeria monocytogenes CadC Regulates Cadmium Efflux and Fine-tunes Lipoprotein Localization to Escape the Host Immune Response and Promote Infection.

PubMed

Pombinho, Rita; Camejo, Ana; Vieira, Ana; Reis, Olga; Carvalho, Filipe; Almeida, Maria Teresa; Pinheiro, Jorge Campos; Sousa, Sandra; Cabanes, Didier

2017-05-01

Listeria monocytogenes is a major intracellular human foodborne bacterial pathogen. We previously revealed L. monocytogenes cadC as highly expressed during mouse infection. Here we show that L. monocytogenes CadC is a sequence-specific, DNA-binding and cadmium-dependent regulator of CadA, an efflux pump conferring cadmium resistance. CadC but not CadA is required for L. monocytogenes infection in vivo. Interestingly, CadC also directly represses lspB, a gene encoding a lipoprotein signal peptidase whose expression appears detrimental for infection. lspB overexpression promotes the release of the LpeA lipoprotein to the extracellular medium, inducing tumor necrosis factor α and interleukin 6 expression, thus impairing L. monocytogenes survival in macrophages. We propose that L. monocytogenes uses CadC to repress lspB expression during infection to avoid LpeA exposure to the host immune system, diminishing inflammatory cytokine expression and promoting intramacrophagic survival and virulence. CadC appears as the first metal efflux pump regulator repurposed during infection to fine-tune lipoprotein processing and host responses. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Comparative fracture strength analysis of Lava and Digident CAD/CAM zirconia ceramic crowns

PubMed Central

Kwon, Taek-Ka; Pak, Hyun-Soon; Han, Jung-Suk; Lee, Jai-Bong; Kim, Sung-Hun

2013-01-01

PURPOSE All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. MATERIALS AND METHODS Twenty Lava CAD/CAM zirconia crowns and twenty Digident CAD/CAM zirconia crowns were fabricated. A metal die was also duplicated from the original prepared tooth for fracture testing. A universal testing machine was used to determine the fracture strength of the crowns. RESULTS The mean fracture strengths were as follows: 54.9 ± 15.6 N for the Lava CAD/CAM zirconia crowns and 87.0 ± 16.0 N for the Digident CAD/CAM zirconia crowns. The difference between the mean fracture strengths of the Lava and Digident crowns was statistically significant (P<.001). Lava CAD/CAM zirconia crowns showed a complete fracture of both the veneering porcelain and the core whereas the Digident CAD/CAM zirconia crowns showed fracture only of the veneering porcelain. CONCLUSION The fracture strengths of CAD/CAM zirconia crowns differ depending on the compatibility of the core material and the veneering porcelain. PMID:23755332

[Computed tomography with computer-assisted detection of pulmonary nodules in dogs and cats].

PubMed

Niesterok, C; Piesnack, S; Köhler, C; Ludewig, E; Alef, M; Kiefer, I

2015-01-01

The aim of this study was to assess the potential benefit of computer-assisted detection (CAD) of pulmonary nodules in veterinary medicine. Therefore, the CAD rate was compared to the detection rates of two individual examiners in terms of its sensitivity and false-positive findings. We included 51 dogs and 16 cats with pulmonary nodules previously diagnosed by computed tomography. First, the number of nodules ≥ 3 mm was recorded for each patient by two independent examiners. Subsequently, each examiner used the CAD software for automated nodule detection. With the knowledge of the CAD results, a final consensus decision on the number of nodules was achieved. The software used was a commercially available CAD program. The sensitivity of examiner 1 was 89.2%, while that of examiner 2 reached 87.4%. CAD had a sensitivity of 69.4%. With CAD, the sensitivity of examiner 1 increased to 94.7% and that of examiner 2 to 90.8%. The CAD-system, which we used in our study, had a moderate sensitivity of 69.4%. Despite its severe limitations, with a high level of false-positive and false-negative results, CAD increased the examiners' sensitivity. Therefore, its supportive role in diagnostics appears to be evident.

Optical properties of CAD-CAM ceramic systems.

PubMed

Della Bona, Alvaro; Nogueira, Audrea D; Pecho, Oscar E

2014-09-01

To evaluate the direct transmittance (T%), translucency, opacity and opalescence of CAD-CAM ceramic systems and the correlation between the translucency parameter (TP) and the contrast ratio (CR). Specimens of shades A1, A2 and A3 (n=5) were fabricated from CAD-CAM ceramic blocks (IPS e.max(®) CAD HT and LT, IPS Empress(®) CAD HT and LT, Paradigm™ C, and VITABLOCS(®) Mark II) and polished to 1.0±0.01mm in thickness. A spectrophotometer (Lambda 20) was used to measure T% on the wavelength range of 400-780nm. Another spectrophotometer (VITA Easyshade(®) Advance) was used to measure the CIE L(*)a(*)b(*) coordinates and the reflectance value (Y) of samples on white and black backgrounds. TP, CR and the opalescence parameter (OP) were calculated. Data were statistically analysed using VAF (variance accounting for) coefficient with Cauchy-Schwarz inequality, one-way ANOVA, Tukey's test, Bonferroni correction and Pearson's correlation. T% of some ceramic systems is dependent on the wavelength. The spectral behaviour showed a slight and constant increase in T% up to approximately 550nm, then some ceramics changed the behaviour as the wavelength gets longer. TP and CR values ranged, respectively, from 16.79 to 21.69 and from 0.52 to 0.64 (r(2)=-0.97). OP values ranged from 3.01 to 7.64. The microstructure of CAD-CAM ceramic systems influenced the optical properties. TP and CR showed a strong correlation for all ceramic systems evaluated. Yet, all ceramics showed some degree of light transmittance. In addition to shade, this study showed that other optical properties influence on the natural appearance of dental ceramics. Copyright © 2014 Elsevier Ltd. All rights reserved.

CAD/CAM in dentistry: a historical perspective and view of the future.

PubMed

Rekow, E D

1992-04-01

What can we look forward too? Lots of fun with new CAD/CAM systems that will enhance dentistry, providing quality restorations quickly. The evolution of an array of new versions of already available systems as well as altogether new systems will provide improved quality, expanded capabilities, and increasing user friendliness. And new materials will be more esthetic, wear more nearly like enamel, and strong enough for full crowns and bridges. We can also look forward to lots of change. Because of the cost of CAD/CAM systems, many clinicians are likely to collaborate by sharing a single system. Laboratories and clinicians may collaborate as well, with data being gathered in the operatory and sent to a laboratory via modem. The fabrication would then be done by the laboratory. Other changes that we cannot even predict are likely to occur in dentistry. Exciting times are here. Automation through dental CAD/CAM systems will, most certainly, change the profession. The impact of that change will only be known in the future. But as the future approaches, the systems and materials available to us will continue to evolve, improve, and enhance dentistry.

Region-growing approach to detect microcalcifications in digital mammograms

NASA Astrophysics Data System (ADS)

Shin, Jin-Wook; Chae, Soo-Ik; Sook, Yoon M.; Park, Dong-Sun

2001-09-01

Detecting early symptoms of breast cancer is very important to enhance the possibility of cure. There have been active researches to develop computer-aided diagnosis(CAD) systems detecting early symptoms of breast cancer in digital mammograms. An expert or a CAD system can recognize the early symptoms based on microcalcifications appeared in digital mammographic images. Microcalcifications have higher gray value than surrounding regions, so these can be detected by expanding a region from a local maximum. However the resultant image contains unnecessary elements such as noise, holes and valleys. Mathematical morphology is a good solution to delete regions that are affected by the unnecessary elements. In this paper, we present a method that effectively detects microcalcifications in digital mammograms using a combination of local maximum operation and the region-growing operation.

Computer Aided Design in Engineering Education.

ERIC Educational Resources Information Center

Gobin, R.

1986-01-01

Discusses the use of Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) systems in an undergraduate engineering education program. Provides a rationale for CAD/CAM use in the already existing engineering program. Describes the methods used in choosing the systems, some initial results, and warnings for first-time users. (TW)

Coronary artery disease reporting and data system (CAD-RADSTM): Inter-observer agreement for assessment categories and modifiers.

PubMed

Maroules, Christopher D; Hamilton-Craig, Christian; Branch, Kelley; Lee, James; Cury, Roberto C; Maurovich-Horvat, Pál; Rubinshtein, Ronen; Thomas, Dustin; Williams, Michelle; Guo, Yanshu; Cury, Ricardo C

The Coronary Artery Disease Reporting and Data System (CAD-RADS) provides a lexicon and standardized reporting system for coronary CT angiography. To evaluate inter-observer agreement of the CAD-RADS among an panel of early career and expert readers. Four early career and four expert cardiac imaging readers prospectively and independently evaluated 50 coronary CT angiography cases using the CAD-RADS lexicon. All readers assessed image quality using a five-point Likert scale, with mean Likert score ≥4 designating high image quality, and <4 designating moderate/low image quality. All readers were blinded to medical history and invasive coronary angiography findings. Inter-observer agreement for CAD-RADS assessment categories and modifiers were assessed using intra-class correlation (ICC) and Fleiss' Kappa (κ).The impact of reader experience and image quality on inter-observer agreement was also examined. Inter-observer agreement for CAD-RADS assessment categories was excellent (ICC 0.958, 95% CI 0.938-0.974, p < 0.0001). Agreement among expert readers (ICC 0.925, 95% CI 0.884-0.954) was marginally stronger than for early career readers (ICC 0.904, 95% CI 0.852-0.941), both p < 0.0001. High image quality was associated with stronger agreement than moderate image quality (ICC 0.944, 95% CI 0.886-0.974 vs. ICC 0.887, 95% CI 0.775-0.95, both p < 0.0001). While excellent inter-observer agreement was observed for modifiers S (stent) and G (bypass graft) (both κ = 1.0), only fair agreement (κ = 0.40) was observed for modifier V (high risk plaque). Inter-observer reproducibility of CAD-RADS assessment categories and modifiers is excellent, except for high-risk plaque (modifier V) which demonstrates fair agreement. These results suggest CAD-RADS is feasible for clinical implementation. Copyright © 2017. Published by Elsevier Inc.

Automated detection of analyzable metaphase chromosome cells depicted on scanned digital microscopic images

NASA Astrophysics Data System (ADS)

Qiu, Yuchen; Wang, Xingwei; Chen, Xiaodong; Li, Yuhua; Liu, Hong; Li, Shibo; Zheng, Bin

2010-02-01

Visually searching for analyzable metaphase chromosome cells under microscopes is quite time-consuming and difficult. To improve detection efficiency, consistency, and diagnostic accuracy, an automated microscopic image scanning system was developed and tested to directly acquire digital images with sufficient spatial resolution for clinical diagnosis. A computer-aided detection (CAD) scheme was also developed and integrated into the image scanning system to search for and detect the regions of interest (ROI) that contain analyzable metaphase chromosome cells in the large volume of scanned images acquired from one specimen. Thus, the cytogeneticists only need to observe and interpret the limited number of ROIs. In this study, the high-resolution microscopic image scanning and CAD performance was investigated and evaluated using nine sets of images scanned from either bone marrow (three) or blood (six) specimens for diagnosis of leukemia. The automated CAD-selection results were compared with the visual selection. In the experiment, the cytogeneticists first visually searched for the analyzable metaphase chromosome cells from specimens under microscopes. The specimens were also automated scanned and followed by applying the CAD scheme to detect and save ROIs containing analyzable cells while deleting the others. The automated selected ROIs were then examined by a panel of three cytogeneticists. From the scanned images, CAD selected more analyzable cells than initially visual examinations of the cytogeneticists in both blood and bone marrow specimens. In general, CAD had higher performance in analyzing blood specimens. Even in three bone marrow specimens, CAD selected 50, 22, 9 ROIs, respectively. Except matching with the initially visual selection of 9, 7, and 5 analyzable cells in these three specimens, the cytogeneticists also selected 41, 15 and 4 new analyzable cells, which were missed in initially visual searching. This experiment showed the feasibility of applying this CAD-guided high-resolution microscopic image scanning system to prescreen and select ROIs that may contain analyzable metaphase chromosome cells. The success and the further improvement of this automated scanning system may have great impact on the future clinical practice in genetic laboratories to detect and diagnose diseases.

Spermine modulates the expression of two probable polyamine transporter genes and determines growth responses to cadaverine in Arabidopsis.

PubMed

Sagor, G H M; Berberich, Thomas; Kojima, Seiji; Niitsu, Masaru; Kusano, Tomonobu

2016-06-01

Two genes, LAT1 and OCT1 , are likely to be involved in polyamine transport in Arabidopsis. Endogenous spermine levels modulate their expression and determine the sensitivity to cadaverine. Arabidopsis spermine (Spm) synthase (SPMS) gene-deficient mutant was previously shown to be rather resistant to the diamine cadaverine (Cad). Furthermore, a mutant deficient in polyamine oxidase 4 gene, accumulating about twofold more of Spm than wild type plants, showed increased sensitivity to Cad. It suggests that endogenous Spm content determines growth responses to Cad in Arabidopsis thaliana. Here, we showed that Arabidopsis seedlings pretreated with Spm absorbs more Cad and has shorter root growth, and that the transgenic Arabidopsis plants overexpressing the SPMS gene are hypersensitive to Cad, further supporting the above idea. The transgenic Arabidopsis overexpressing L-Amino acid Transporter 1 (LAT1) absorbed more Cad and showed increased Cad sensitivity, suggesting that LAT1 functions as a Cad importer. Recently, other research group reported that Organic Cation Transporter 1 (OCT1) is a causal gene which determines the Cad sensitivity of various Arabidopsis accessions. Furthermore, their results suggested that OCT1 is involved in Cad efflux. Thus we monitored the expression of OCT1 and LAT1 during the above experiments. Based on the results, we proposed a model in which the level of Spm content modulates the expression of OCT1 and LAT1, and determines Cad sensitivity of Arabidopsis.

Synergism of the method of characteristics and CAD technology for neutron transport calculation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Z.; Wang, D.; He, T.

2013-07-01

The method of characteristics (MOC) is a very popular methodology in neutron transport calculation and numerical simulation in recent decades for its unique advantages. One of the key problems determining whether the MOC can be applied in complicated and highly heterogeneous geometry is how to combine an effective geometry processing method with MOC. Most of the existing MOC codes describe the geometry by lines and arcs with extensive input data, such as circles, ellipses, regular polygons and combination of them. Thus they have difficulty in geometry modeling, background meshing and ray tracing for complicated geometry domains. In this study, amore » new idea making use of a CAD solid modeler MCAM which is a CAD/Image-based Automatic Modeling Program for Neutronics and Radiation Transport developed by FDS Team in China was introduced for geometry modeling and ray tracing of particle transport to remove these geometrical limitations mentioned above. The diamond-difference scheme was applied to MOC to reduce the spatial discretization error of the flat flux approximation in theory. Based on MCAM and MOC, a new MOC code was developed and integrated into SuperMC system, which is a Super Multi-function Computational system for neutronics and radiation simulation. The numerical testing results demonstrated the feasibility and effectiveness of the new idea for geometry treatment in SuperMC. (authors)« less

Aerodynamic Design of Complex Configurations Using Cartesian Methods and CAD Geometry

NASA Technical Reports Server (NTRS)

Nemec, Marian; Aftosmis, Michael J.; Pulliam, Thomas H.

2003-01-01

The objective for this paper is to present the development of an optimization capability for the Cartesian inviscid-flow analysis package of Aftosmis et al. We evaluate and characterize the following modules within the new optimization framework: (1) A component-based geometry parameterization approach using a CAD solid representation and the CAPRI interface. (2) The use of Cartesian methods in the development Optimization techniques using a genetic algorithm. The discussion and investigations focus on several real world problems of the optimization process. We examine the architectural issues associated with the deployment of a CAD-based design approach in a heterogeneous parallel computing environment that contains both CAD workstations and dedicated compute nodes. In addition, we study the influence of noise on the performance of optimization techniques, and the overall efficiency of the optimization process for aerodynamic design of complex three-dimensional configurations. of automated optimization tools. rithm and a gradient-based algorithm.

Biaxial flexural strength of CAD/CAM ceramics.

PubMed

Buso, L; Oliveira-Júnior, O B; Hiroshi Fujiy, F; Leão Lombardo, G H; Ramalho Sarmento, H; Campos, F; Assunção Souza, R O

2011-06-01

Aim of the study was to evaluate the biaxial flexural strength of ceramics processed using the Cerec inLab system. The hypothesis was that the flexural strength would be influenced by the type of ceramic. Ten samples (ISO 6872) of each ceramic (N.=50/n.=10) were made using Cerec inLab (software Cerec 3D) (Ø:15 mm, thickness: 1.2 mm). Three silica-based ceramics (Vita Mark II [VM], ProCad [PC] and e-max CAD ECAD]) and two yttria-stabilized tetragonal-zirconia-polycrystalline ceramics (Y-TZP) (e-max ZirCad [ZrCAD] and Vita In-Ceram 2000 YZ Cubes [VYZ]) were tested. The samples were finished with wet silicone carbide papers up to 1 200-grit and polished in a polishing machine with diamond paste (3 µm). The samples were then submitted to biaxial flexural strength testing in a universal testing machine (EMIC), 1 mm/min. The data (MPa) were analyzed using the Kruskal-Wallis and Dunn (5%) tests. Scanning electronic microscopy (SEM) was performed on a representative sample from each group. The values (median, mean±sd) obtained for the experimental groups were: VM (101.7, 102.1±13.65 MPa), PC (165.2, 160±34.7 MPa), ECAD (437.2, 416.1±50.1 MPa), ZrCAD (804.2, 800.8±64.47 MPa) and VYZ (792.7, 807±100.7 MPa). The type of ceramic influenced the flexural strength values (P=0.0001). The ceramics ECADa, e-max ZrCADa and VYZa presented similar flexural strength values which were significantly higher than the other groups (PCb and VM IIb), which were similar statistically between them (Dunn's test). The hypothesis was accepted. The polycrystalline ceramics (Y-TZP) should be material chosen for make FPDs because of their higher flexural strength values.

Fatigue Resistance of CAD/CAM Resin Composite Molar Crowns

PubMed Central

Shembish, Fatma A.; Tong, Hui; Kaizer, Marina; Janal, Malvin N.; Thompson, Van P.; Opdam, Niek J.; Zhang, Yu

2016-01-01

Objective To demonstrate the fatigue behavior of CAD/CAM resin composite molar crowns using a mouth-motion step-stress fatigue test. Monolithic leucite-reinforced glass-ceramic crowns were used as a reference. Methods Fully anatomically shaped monolithic resin composite molar crowns (Lava Ultimate, n = 24) and leucite reinforced glass-ceramic crowns (IPS Empress CAD, n = 24) were fabricated using CAD/CAM systems. Crowns were cemented on aged dentin-like resin composite tooth replicas (Filtek Z100) with resin-based cements (RelyX Ultimate for Lava Ultimate or Multilink Automix for IPS Empress). Three step-stress profiles (aggressive, moderate and mild) were employed for the accelerated sliding-contact mouth-motion fatigue test. Twenty one crowns from each group were randomly distributed among these three profiles (1:2:4). Failure was designated as chip-off or bulk fracture. Optical and electronic microscopes were used to examine the occlusal surface and subsurface damages, as well as the material microstructures. Results The resin composite crowns showed only minor occlusal damage during mouth-motion step-stress fatigue loading up to 1700 N. Cross-sectional views revealed contact-induced cone cracks in all specimens, and flexural radial cracks in 2 crowns. Both cone and radial cracks were relatively small compared to the crown thickness. Extending these cracks to the threshold for catastrophic failure would require much higher indentation loads or more loading cycles. In contrast, all of the glass-ceramic crowns fractured, starting at loads of approximately 450 N. Significance Monolithic CAD/CAM resin composite crowns endure, with only superficial damage, fatigue loads 3 – 4 times higher than those causing catastrophic failure in glass-ceramic CAD crowns. PMID:26777092

Productivity increase through implementation of CAD/CAE workstation

NASA Technical Reports Server (NTRS)

Bromley, L. K.

1985-01-01

The tracking and communication division computer aided design/computer aided engineering system is now operational. The system is utilized in an effort to automate certain tasks that were previously performed manually. These tasks include detailed test configuration diagrams of systems under certification test in the ESTL, floorplan layouts of future planned laboratory reconfigurations, and other graphical documentation of division activities. The significant time savings achieved with this CAD/CAE system are examined: (1) input of drawings and diagrams; (2) editing of initial drawings; (3) accessibility of the data; and (4) added versatility. It is shown that the Applicon CAD/CAE system, with its ease of input and editing, the accessibility of data, and its added versatility, has made more efficient many of the necessary but often time-consuming tasks associated with engineering design and testing.

Preparation of chitosan/amine modified diatomite composites and adsorption properties of Hg(II) ions.

PubMed

Fu, Yong; Huang, Yue; Hu, Jianshe; Zhang, Zhengjie

2018-03-01

A green functional adsorbent (CAD) was prepared by Schiff base reaction of chitosan and amino-modified diatomite. The morphology, structure and adsorption properties of the CAD were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and Brunauer Emmett Teller measurements. The effect of pH value, contact time and temperature on the adsorption of Hg(II) ions for the CAD is discussed in detail. The experimental results showed that the CAD had a large specific surface area and multifunctional groups such as amino, hydroxyl and Schiff base. The optimum adsorption effect was obtained when the pH value, temperature and contact time were 4, 25 °C and 120 min, respectively, and the corresponding maximum adsorption capacity of Hg(II) ions reached 102 mg/g. Moreover, the adsorption behavior of Hg(II) ions for the CAD followed the pseudo-second-order kinetic model and Langmuir model. The negative ΔG 0 and ΔH 0 suggested that the adsorption was a spontaneous exothermic process.

Computation-aware algorithm selection approach for interlaced-to-progressive conversion

NASA Astrophysics Data System (ADS)

Park, Sang-Jun; Jeon, Gwanggil; Jeong, Jechang

2010-05-01

We discuss deinterlacing results in a computationally constrained and varied environment. The proposed computation-aware algorithm selection approach (CASA) for fast interlaced to progressive conversion algorithm consists of three methods: the line-averaging (LA) method for plain regions, the modified edge-based line-averaging (MELA) method for medium regions, and the proposed covariance-based adaptive deinterlacing (CAD) method for complex regions. The proposed CASA uses two criteria, mean-squared error (MSE) and CPU time, for assigning the method. We proposed a CAD method. The principle idea of CAD is based on the correspondence between the high and low-resolution covariances. We estimated the local covariance coefficients from an interlaced image using Wiener filtering theory and then used these optimal minimum MSE interpolation coefficients to obtain a deinterlaced image. The CAD method, though more robust than most known methods, was not found to be very fast compared to the others. To alleviate this issue, we proposed an adaptive selection approach using a fast deinterlacing algorithm rather than using only one CAD algorithm. The proposed hybrid approach of switching between the conventional schemes (LA and MELA) and our CAD was proposed to reduce the overall computational load. A reliable condition to be used for switching the schemes was presented after a wide set of initial training processes. The results of computer simulations showed that the proposed methods outperformed a number of methods presented in the literature.

A managed care organization's use of integrated health management to improve secondary prevention of coronary artery disease.

PubMed

Berthiaume, John T; Davis, Jim; Taira, Deborah A; Thein, Ko Ko

2007-03-01

To evaluate the effect of a managed care organization's multifactorial intervention program in optimizing secondary prevention of coronary artery disease (CAD). Retrospective observational analysis of claims-based data of health plan members with CAD receiving 1 or more prescriptions per year of any of the following classes of medications used for secondary prevention of CAD: lipid-lowering agents, angiotensin-converting enzyme (ACE) inhibitors, or angiotensin receptor blockers (ARBs) and beta-blockers. Claims-based data of members from 2000 to 2004 were analyzed to discover trends in the use of medications for secondary prevention of CAD. chi(2) Test of proportion was used to determine whether the changes in the annual medication use rates were statistically significant. The annual medication use rates improved consistently throughout each year of the study period. From 2000 to 2004, the medication use rates increased for lipid-lowering agents (from 55% to 71%), ACE inhibitors or ARBs (from 44% to 55%), and beta-blockers (from 36% to 47%). Changes in all 3 indicators were statistically significant at P < .001. An integrated multifactorial approach is essential in addressing the underutilization of therapies available for secondary prevention of CAD. Managed care organizations are in a unique position to optimize the use of evidence-based pharmacological and behavioral therapies to effectively prevent and treat the underlying pathophysiology of CAD in member populations.

GridTool: A surface modeling and grid generation tool

NASA Technical Reports Server (NTRS)

Samareh-Abolhassani, Jamshid

1995-01-01

GridTool is designed around the concept that the surface grids are generated on a set of bi-linear patches. This type of grid generation is quite easy to implement, and it avoids the problems associated with complex CAD surface representations and associated surface parameterizations. However, the resulting surface grids are close to but not on the original CAD surfaces. This problem can be alleviated by projecting the resulting surface grids onto the original CAD surfaces. GridTool is designed primary for unstructured grid generation systems. Currently, GridTool supports VGRID and FELISA systems, and it can be easily extended to support other unstructured grid generation systems. The data in GridTool is stored parametrically so that once the problem is set up, one can modify the surfaces and the entire set of points, curves and patches will be updated automatically. This is very useful in a multidisciplinary design and optimization process. GridTool is written entirely in ANSI 'C', the interface is based on the FORMS library, and the graphics is based on the GL library. The code has been tested successfully on IRIS workstations running IRIX4.0 and above. The memory is allocated dynamically, therefore, memory size will depend on the complexity of geometry/grid. GridTool data structure is based on a link-list structure which allows the required memory to expand and contract dynamically according to the user's data size and action. Data structure contains several types of objects such as points, curves, patches, sources and surfaces. At any given time, there is always an active object which is drawn in magenta, or in their highlighted colors as defined by the resource file which will be discussed later.

Development of an integrated CAD-FEA system for patient-specific design of spinal cages.

PubMed

Zhang, Mingzheng; Pu, Fang; Xu, Liqiang; Zhang, Linlin; Liang, Hang; Li, Deyu; Wang, Yu; Fan, Yubo

2017-03-01

Spinal cages are used to create a suitable mechanical environment for interbody fusion in cases of degenerative spinal instability. Due to individual variations in bone structures and pathological conditions, patient-specific cages can provide optimal biomechanical conditions for fusion, strengthening patient recovery. Finite element analysis (FEA) is a valuable tool in the biomechanical evaluation of patient-specific cage designs, but the time- and labor-intensive process of modeling limits its clinical application. In an effort to facilitate the design and analysis of patient-specific spinal cages, an integrated CAD-FEA system (CASCaDeS, comprehensive analytical spinal cage design system) was developed. This system produces a biomechanical-based patient-specific design of spinal cages and is capable of rapid implementation of finite element modeling. By comparison with commercial software, this system was validated and proven to be both accurate and efficient. CASCaDeS can be used to design patient-specific cages with a superior biomechanical performance to commercial spinal cages.

CEREC Chairside System to Register and Design the Occlusion in Restorative Dentistry: A Systematic Literature Review.

PubMed

Bohner, Lauren Oliveira Lima; Neto, Pedro Tortamano; Ahmed, Ahad Shahid; Mori, Matsuyoshi; Laganá, Dalva Cruz; Sesma, Newton

2016-07-01

The aim of this review was to update the literature with regard to the digital methods available by CEREC Chairside system to register and design the occlusion, to report their efficacy and technical innovations in the field of Restorative Dentistry. A search strategy was performed using the key-words: "virtual articulator," or "CAD-CAM and occlusal recording," or "CAD-CAM and occlusion register," or "CAD-CAM and occlusal contacts," or "CAD-CAM and prosthesis." Inclusion criteria comprised studies evaluating the use of digital methods available by CEREC System for occlusal registration and design during prosthodontics treatment. PubMed and Cochrane library and reference lists were searched up to January 2016. The search resulted in 280 articles after removing duplicates. Subsequently, 233 records were excluded and 49 studies were selected for reading in full. Eleven articles were considered eligible for the systematic review (4 in vitro and 7 clinical studies). Scientific evidence suggests that digital methods were accurate to register and design the occlusion of dental prostheses. Nevertheless, further clinical studies are required to establish a conclusion with regard to its accuracy in prosthodontics treatment. Digital technologies allow the design of occlusal surfaces of CAD-CAM fabricated prostheses using innovative approaches. This systematic review aimed to update the literature to help dentists determine the most appropriate digital method to register and design the occlusal surface of CAD-CAM crowns. (J Esthet Restor Dent 28:208-220, 2016). © 2016 Wiley Periodicals, Inc.

The Z-cad dual fluorescent sensor detects dynamic changes between the epithelial and mesenchymal cellular states.

PubMed

Toneff, M J; Sreekumar, A; Tinnirello, A; Hollander, P Den; Habib, S; Li, S; Ellis, M J; Xin, L; Mani, S A; Rosen, J M

2016-06-17

The epithelial to mesenchymal transition (EMT) has been implicated in metastasis and therapy resistance of carcinomas and can endow cancer cells with cancer stem cell (CSC) properties. The ability to detect cancer cells that are undergoing or have completed EMT has typically relied on the expression of cell surface antigens that correlate with an EMT/CSC phenotype. Alternatively these cells may be permanently marked through Cre-mediated recombination or through immunostaining of fixed cells. The EMT process is dynamic, and these existing methods cannot reveal such changes within live cells. The development of fluorescent sensors that mirror the dynamic EMT state by following the expression of bona fide EMT regulators in live cells would provide a valuable new tool for characterizing EMT. In addition, these sensors will allow direct observation of cellular plasticity with respect to the epithelial/mesenchymal state to enable more effective studies of EMT in cancer and development. We generated a lentiviral-based, dual fluorescent reporter system, designated as the Z-cad dual sensor, comprising destabilized green fluorescent protein containing the ZEB1 3' UTR and red fluorescent protein driven by the E-cadherin (CDH1) promoter. Using this sensor, we robustly detected EMT and mesenchymal to epithelial transition (MET) in breast cancer cells by flow cytometry and fluorescence microscopy. Importantly, we observed dynamic changes in cellular populations undergoing MET. Additionally, we used the Z-cad sensor to identify and isolate minor subpopulations of cells displaying mesenchymal properties within a population comprising predominately epithelial-like cells. The Z-cad dual sensor identified cells with CSC-like properties more effectively than either the ZEB1 3' UTR or E-cadherin sensor alone. The Z-cad dual sensor effectively reports the activities of two factors critical in determining the epithelial/mesenchymal state of carcinoma cells. The ability of this stably integrating dual sensor system to detect dynamic fluctuations between these two states through live cell imaging offers a significant improvement over existing methods and helps facilitate the study of EMT/MET plasticity in response to different stimuli and in cancer pathogenesis. Finally, the versatile Z-cad sensor can be adapted to a variety of in vitro or in vivo systems to elucidate whether EMT/MET contributes to normal and disease phenotypes.

CAD-supported university course on photonics and fiber optic communications

NASA Astrophysics Data System (ADS)

Chan, David K. C.; Richter, Andre

2002-05-01

The highly competitive global photonics industry has created a significant demand for professional Photonic Design Automation (PDA) tools and personnel trained to use them effectively. In such a dynamic field, CAD-supported courses built around widely used industrial PDA tools provide many advantages, especially when offered through tertiary education institutions (which are ideally suited to producing the future workforce of the Photonics industry). An objective of VPIsystems' University program is to develop tertiary level courses based on VPIsystems' WDM transmission and component modeling software tools. Advantages offered by such courses include: visualizing and aiding the understanding of complex physical problems encountered in the design of fiber-optic communication systems; virtual laboratory exercises that can accurately reproduce the behavior of real systems and components without the prohibitive infrastructure and maintenance costs of real laboratories; flexibility in studying interrelated physical effects individually or in combination to facilitate learning; provide expertise and practical insights in areas, including industry-focused topics, that are not generally covered in traditional tertiary courses; provide exposure to, currently, the most widely used PDA tools in the industry. In this paper, details of VPIsystems' University program and its CAD-supported Photonics courses will be presented.

Coronary Artery Disease and Reticular Macular Disease, a Subphenotype of Early Age-Related Macular Degeneration.

PubMed

Cymerman, Rachel M; Skolnick, Adam H; Cole, William J; Nabati, Camellia; Curcio, Christine A; Smith, R Theodore

2016-11-01

Reticular macular disease (RMD) is the highest risk form of early age-related macular degeneration and also specifically confers decreased longevity. However, because RMD requires advanced retinal imaging for adequate detection of its characteristic subretinal drusenoid deposits (SDD), it has not yet been completely studied with respect to coronary artery disease (CAD), the leading cause of death in the developed world. Because CAD appears in middle age, our purpose was to screen patients aged 45-80 years, documented either with or without CAD, to determine if CAD is associated with RMD. A prospective cohort study of patients with documented CAD status and no known retinal disease in a clinical practice setting at one institution. Subjects and Controls: A number of 76 eyes from 38 consecutive patients (23 with documented CAD, 15 controls documented without CAD; 47.4% female; mean age 66.7 years). Patients were imaged with near-infrared reflectance/spectral domain optical coherence tomography and assessed in masked fashion by two graders for the presence of SDD lesions of RMD and soft drusen. Presence or absence of RMD/SDD and soft drusen. RMD was more frequent in patients with CAD versus those without (Relative Risk [RR] = 2.1, CI = 1.08-3.95, P = 0.03). There was no association of CAD with soft drusen. A specific relationship between CAD and RMD suggests common systemic causes for both and warrants further study.

Improving mass candidate detection in mammograms via feature maxima propagation and local feature selection.

PubMed

Melendez, Jaime; Sánchez, Clara I; van Ginneken, Bram; Karssemeijer, Nico

2014-08-01

Mass candidate detection is a crucial component of multistep computer-aided detection (CAD) systems. It is usually performed by combining several local features by means of a classifier. When these features are processed on a per-image-location basis (e.g., for each pixel), mismatching problems may arise while constructing feature vectors for classification, which is especially true when the behavior expected from the evaluated features is a peaked response due to the presence of a mass. In this study, two of these problems, consisting of maxima misalignment and differences of maxima spread, are identified and two solutions are proposed. The first proposed method, feature maxima propagation, reproduces feature maxima through their neighboring locations. The second method, local feature selection, combines different subsets of features for different feature vectors associated with image locations. Both methods are applied independently and together. The proposed methods are included in a mammogram-based CAD system intended for mass detection in screening. Experiments are carried out with a database of 382 digital cases. Sensitivity is assessed at two sets of operating points. The first one is the interval of 3.5-15 false positives per image (FPs/image), which is typical for mass candidate detection. The second one is 1 FP/image, which allows to estimate the quality of the mass candidate detector's output for use in subsequent steps of the CAD system. The best results are obtained when the proposed methods are applied together. In that case, the mean sensitivity in the interval of 3.5-15 FPs/image significantly increases from 0.926 to 0.958 (p < 0.0002). At the lower rate of 1 FP/image, the mean sensitivity improves from 0.628 to 0.734 (p < 0.0002). Given the improved detection performance, the authors believe that the strategies proposed in this paper can render mass candidate detection approaches based on image location classification more robust to feature discrepancies and prove advantageous not only at the candidate detection level, but also at subsequent steps of a CAD system.

Analysis of HOM Problems in the C-ADS Main Linac

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Burn; Ng, King Yuen

2017-05-18

Excitation of higher-order modes (HOMs) in superconducting cavities may severely affect the operation of the main linac in the Chinese Accelerator Driven System (CADS). Preliminary analysis is made on the effects of beam dynamic, which includes possible longitudinal and transverse emittance enlargements, as well as the possibility of beam breakup. Suggestions are given for further investigation. Comparison is made between the C-ADS and the Fermilab Project X.

Integrating three-dimensional digital technologies for comprehensive implant dentistry.

PubMed

Patel, Neal

2010-06-01

The increase in the popularity of and the demand for the use of dental implants to replace teeth has encouraged advancement in clinical technology and materials to improve patients' acceptance and clinical outcomes. Recent advances such as three-dimensional dental radiography with cone-beam computed tomography (CBCT), precision dental implant planning software and clinical execution with guided surgery all play a role in the success of implant dentistry. The author illustrates the technique of comprehensive implant dentistry planning through integration of computer-aided design/computer-aided manufacturing (CAD/CAM) and CBCT data. The technique includes clinical treatment with guided surgery, including the creation of a final restoration with a high-strength ceramic (IPS e.max CAD, Ivoclar Vivadent, Amherst, N.Y.). The author also introduces a technique involving CAD/CAM for fabricating custom implant abutments. The release of software integrating CEREC Acquisition Center with Bluecam (Sirona Dental Systems, Charlotte, N.C.) chairside CAD/CAM and Galileos CBCT imaging (Sirona Dental Systems) allows dentists to plan implant placement, perform implant dentistry with increased precision and provide predictable restorative results by using chairside IPS e.max CAD. The precision of clinical treatment provided by the integration of CAD/CAM and CBCT allows dentists to plan for ideal surgical placement and the appropriate thickness of restorative modalities before placing implants.

Comparison of plasma adiponectin & certain inflammatory markers in angiographically proven coronary artery disease patients with & without diabetes – A study from India

PubMed Central

Kumpatla, Satyavani; Karuppiah, Kirubakaran; Immaneni, Sathyamurthy; Muthukumaran, Parthiban; Krishnan, Jayanthi; Narayanamoorthy, Srinivasan Kanthallu; Viswanathan, Vijay

2014-01-01

Background & objectives: The association between adiponectin and risk of cardiovascular disease is well known. The aim of the present study was to evaluate adiponectin and certain inflammatory markers and to determine the correlations between them in angiographically proven coronary artery disease (CAD) in subjects with and without diabetes. Methods: A total of 180 subjects who underwent coronary angiography for symptoms suggestive of CAD were categorised into groups based on their diabetes and/or CAD status: group1 (non-diabetic non-CAD); group2 (non-diabetic CAD); group3 (diabetic non-CAD) and group4 (diabetic CAD). Adiponectin, tumour necrosis factor α (TNF-α) and soluble form of E-selectin (sE-selectin) were estimated using quantitative sandwich enzyme immunoassay and high sensitive C-reactive protein (hsCRP) by particle enhanced immunoturbidimetric method. Results: Adiponectin levels were significantly lower in subjects with either diabetes or CAD and were much lower in subjects who had both. hsCRP was elevated in CAD and diabetes but did not differ significantly between groups. sE-selectin and TNF-α levels were elevated in CAD. Adiponectin negatively correlated with age, glucose, sE-selectin, total and LDL cholesterol. hsCRP correlated with BMI, sE-selectin and urea. sE-selectin correlated with BMI, triglycerides and VLDL cholesterol, whereas TNF-α correlated with fasting plasma glucose. In the logistic regression analysis, adiponectin had a significant inverse association with CAD. sE-selectin and TNF-α also showed significant independent association with CAD. Interpretation & conclusions: Adiponectin and other inflammatory markers such as sE-selectin and TNF-α showed a significant association with CAD. Hence, early assessment of such markers can help to identify high risk patients, and to reduce the inflammatory component of diabetes and CAD. PMID:25109718

[National disease management guidelines (NVL) for chronic CAD : What is new, what is particularly important?].

PubMed

Werdan, K

2016-09-01

Coronary heart disease (CAD) is widespread and affects 1 in 10 of the population in the age group 40-79 years in Germany. The German national management guidelines on chronic CAD comprise evidence and expert-based recommendations for the diagnostics of chronic stable CAD as well as for interdisciplinary/multidisciplinary therapy and care of patients with stable CAD. The focus is on the diagnostics, prevention, medication therapy, revascularization, rehabilitation, general practitioner care and coordination of care. Recommendations for optimizing cooperation between all medical specialties involved as well as the definition of mandatory and appropriate measures are essential aims of the guidelines both to improve the quality of care and to strengthen the position of the patient.

Virtual Reality-Based Technologies in Dental Medicine: Knowledge, Attitudes and Practice among Students and Practitioners

ERIC Educational Resources Information Center

Sabalic, Maja; Schoener, Jason D.

2017-01-01

Virtual reality-based technologies have been used in dentistry for almost two decades. Dental simulators, planning software and CAD/CAM (computer-aided design/computer-aided manufacturing) systems have significantly developed over the years and changed both dental education and clinical practice. This study aimed to assess the knowledge, attitudes…

A/E/C CAD Standard, Release 4.0

DTIC Science & Technology

2009-07-01

Insulating (Transformer) Oil System Lubrication Oil Hot Water Heating System Machine Design Appendix A Model File Level/Layer Assignment Tables A51...of the A /E/C CAD Standard are:  “Uniform Drawing System ” The Construction Specifications Institute 99 Canal Center Plaza, Suite 300 Alexandria, VA...FM – Facility Management  GIS – Geographic Information System  IAI – International Alliance for Interoperability  IFC – Industry Foundation

Increasing productivity of the McAuto CAD/CAE system by user-specific applications programming

NASA Technical Reports Server (NTRS)

Plotrowski, S. M.; Vu, T. H.

1985-01-01

Significant improvements in the productivity of the McAuto Computer-Aided Design/Computer-Aided Engineering (CAD/CAE) system were achieved by applications programming using the system's own Graphics Interactive Programming language (GRIP) and the interface capabilities with the main computer on which the system resides. The GRIP programs for creating springs, bar charts, finite element model representations and aiding management planning are presented as examples.

Research on computer-aided design of modern marine power systems

NASA Astrophysics Data System (ADS)

Ding, Dongdong; Zeng, Fanming; Chen, Guojun

2004-03-01

To make the MPS (Marine Power System) design process more economical and easier, a new CAD scheme is brought forward which takes much advantage of VR (Virtual Reality) and AI (Artificial Intelligence) technologies. This CAD system can shorten the period of design and reduce the requirements on designers' experience in large scale. And some key issues like the selection of hardware and software of such a system are discussed.

Structural MRI-based detection of Alzheimer's disease using feature ranking and classification error.

PubMed

Beheshti, Iman; Demirel, Hasan; Farokhian, Farnaz; Yang, Chunlan; Matsuda, Hiroshi

2016-12-01

This paper presents an automatic computer-aided diagnosis (CAD) system based on feature ranking for detection of Alzheimer's disease (AD) using structural magnetic resonance imaging (sMRI) data. The proposed CAD system is composed of four systematic stages. First, global and local differences in the gray matter (GM) of AD patients compared to the GM of healthy controls (HCs) are analyzed using a voxel-based morphometry technique. The aim is to identify significant local differences in the volume of GM as volumes of interests (VOIs). Second, the voxel intensity values of the VOIs are extracted as raw features. Third, the raw features are ranked using a seven-feature ranking method, namely, statistical dependency (SD), mutual information (MI), information gain (IG), Pearson's correlation coefficient (PCC), t-test score (TS), Fisher's criterion (FC), and the Gini index (GI). The features with higher scores are more discriminative. To determine the number of top features, the estimated classification error based on training set made up of the AD and HC groups is calculated, with the vector size that minimized this error selected as the top discriminative feature. Fourth, the classification is performed using a support vector machine (SVM). In addition, a data fusion approach among feature ranking methods is introduced to improve the classification performance. The proposed method is evaluated using a data-set from ADNI (130 AD and 130 HC) with 10-fold cross-validation. The classification accuracy of the proposed automatic system for the diagnosis of AD is up to 92.48% using the sMRI data. An automatic CAD system for the classification of AD based on feature-ranking method and classification errors is proposed. In this regard, seven-feature ranking methods (i.e., SD, MI, IG, PCC, TS, FC, and GI) are evaluated. The optimal size of top discriminative features is determined by the classification error estimation in the training phase. The experimental results indicate that the performance of the proposed system is comparative to that of state-of-the-art classification models. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

[Computer aided design for fixed partial denture framework based on reverse engineering technology].

PubMed

Sun, Yu-chun; Lü, Pei-jun; Wang, Yong

2006-03-01

To explore a computer aided design (CAD) route for the framework of domestic fixed partial denture (FPD) and confirm the suitable method of 3-D CAD. The working area of a dentition model was scanned with a 3-D mechanical scanner. Using the reverse engineering (RE) software, margin and border curves were extracted and several reference curves were created to ensure the dimension and location of pontic framework that was taken from the standard database. The shoulder parts of the retainers were created after axial surfaces constructed. The connecting areas, axial line and curving surface of the framework connector were finally created. The framework of a three-unit FPD was designed with RE technology, which showed smooth surfaces and continuous contours. The design route is practical. The result of this study is significant in theory and practice, which will provide a reference for establishing the computer aided design/computer aided manufacture (CAD/CAM) system of domestic FPD.

Web-Based Learning in the Computer-Aided Design Curriculum.

ERIC Educational Resources Information Center

Sung, Wen-Tsai; Ou, S. C.

2002-01-01

Applies principles of constructivism and virtual reality (VR) to computer-aided design (CAD) curriculum, particularly engineering, by integrating network, VR and CAD technologies into a Web-based learning environment that expands traditional two-dimensional computer graphics into a three-dimensional real-time simulation that enhances user…

Effects of combined vitamin D--calcium supplements on the cardiovascular system: should we be cautious?

PubMed

Challoumas, Dimitrios; Stavrou, Antonio; Pericleous, Agamemnon; Dimitrakakis, Georgios

2015-02-01

Despite the growing body of evidence on the potential effects of calcium and vitamin D as monotherapies on different cardiovascular (CV) parameters, the combined supplementation with calcium and vitamin D (CaD), which is most frequently encountered in clinical practice, has not received the attention it deserves. A literature search was conducted via EMBASE and Medline and identified 14 randomised controlled trials (RCTs) and 2 meta-analyses reporting on effects of combined supplementation with CaD on CV events, CV death, blood pressure, lipids, glucose metabolism and weight. Overall, the existing evidence does not support beneficial properties of supplementation with CaD on the CV system, nor does it suggest that a re-appraisal of the use of CaD is necessary due to adverse effects, although increased risk of CV events has been reported by some authors. The guidelines for the use of CaD supplementation need not change until well-conducted RCTs that have CV effects as primary outcomes and adjust for major confounders indicate otherwise. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Automated diagnosis of coronary artery disease based on data mining and fuzzy modeling.

PubMed

Tsipouras, Markos G; Exarchos, Themis P; Fotiadis, Dimitrios I; Kotsia, Anna P; Vakalis, Konstantinos V; Naka, Katerina K; Michalis, Lampros K

2008-07-01

A fuzzy rule-based decision support system (DSS) is presented for the diagnosis of coronary artery disease (CAD). The system is automatically generated from an initial annotated dataset, using a four stage methodology: 1) induction of a decision tree from the data; 2) extraction of a set of rules from the decision tree, in disjunctive normal form and formulation of a crisp model; 3) transformation of the crisp set of rules into a fuzzy model; and 4) optimization of the parameters of the fuzzy model. The dataset used for the DSS generation and evaluation consists of 199 subjects, each one characterized by 19 features, including demographic and history data, as well as laboratory examinations. Tenfold cross validation is employed, and the average sensitivity and specificity obtained is 62% and 54%, respectively, using the set of rules extracted from the decision tree (first and second stages), while the average sensitivity and specificity increase to 80% and 65%, respectively, when the fuzzification and optimization stages are used. The system offers several advantages since it is automatically generated, it provides CAD diagnosis based on easily and noninvasively acquired features, and is able to provide interpretation for the decisions made.

A User Modelling Approach for Computer-Based Critiquing

DTIC Science & Technology

1990-01-01

example a CAD/CAM system). Com- puters are good for simulating in circumstances where training on the actual equip- 13 ment (for example a power plant or...system. It is an environment in which simulated devices, such as steam plant controllers, can be assembled and operated. Students can assemble a...Con- cordia hypermedia system, graphics can be integrated easily. Concordia is a hy- permedia development and presentation system available on the

Validation of the association between a branched chain amino acid metabolite profile and extremes of coronary artery disease in patients referred for cardiac catheterization.

PubMed

Bhattacharya, Sayanti; Granger, Christopher B; Craig, Damian; Haynes, Carol; Bain, James; Stevens, Robert D; Hauser, Elizabeth R; Newgard, Christopher B; Kraus, William E; Newby, L Kristin; Shah, Svati H

2014-01-01

To validate independent associations between branched-chain amino acids (BCAA) and other metabolites with coronary artery disease (CAD). We conducted mass-spectrometry-based profiling of 63 metabolites in fasting plasma from 1983 sequential patients undergoing cardiac catheterization. Significant CAD was defined as CADindex ≥ 32 (at least one vessel with ≥ 95% stenosis; N = 995) and no CAD as CADindex ≤ 23 and no previous cardiac events (N = 610). Individuals (N = 378) with CAD severity between these extremes were excluded. Principal components analysis (PCA) reduced large numbers of correlated metabolites into uncorrelated factors. Association between metabolite factors and significant CAD vs. no CAD was tested using logistic regression; and between metabolite factors and severity of CAD was tested using linear regression. Of twelve PCA-derived metabolite factors, two were associated with CAD in multivariable models: factor 10, composed of BCAA (adjusted odds ratio, OR, 1.20; 95% CI 1.05-1.35, p = 0.005) and factor 7, composed of short-chain acylcarnitines, which include byproducts of BCAA metabolism (adjusted OR 1.30; 95% CI 1.14-1.48, p = 0.001). After adjustment for glycated albumin (marker of insulin resistance [IR]) both factors 7 (p = 0.0001) and 10 (p = 0.004) remained associated with CAD. Severity of CAD as a continuous variable (including patients with non-obstructive disease) was associated with metabolite factors 2, 3, 6, 7, 8 and 9; only factors 7 and 10 were associated in multivariable models. We validated the independent association of metabolites involved in BCAA metabolism with CAD extremes. These metabolites may be reporting on novel mechanisms of CAD pathogenesis that are independent of IR and diabetes. Copyright © 2013. Published by Elsevier Ireland Ltd.

Genetic variants associated with celiac disease and the risk for coronary artery disease.

PubMed

Jansen, Henning; Willenborg, Christina; Schlesinger, Sabrina; Ferrario, Paola G; König, Inke R; Erdmann, Jeanette; Samani, Nilesh J; Lieb, Wolfgang; Schunkert, Heribert

2015-10-01

Epidemiological evidence suggests that patients with celiac disease are at increased risk for coronary artery disease (CAD). Genetic-epidemiological analyses identified many single nucleotide polymorphisms (SNPs) associated with celiac disease. If there is a causal relation between celiac disease and CAD, one might expect that risk alleles primarily associated with celiac disease also increase the risk of CAD. In this study we identified from literature 41 SNPs that have been previously described to be genome-wide associated with celiac disease (p < 5 × 10(-08)). These SNPs were evaluated for their association with CAD in the Coronary ARtery DIsease Genome-wide Replication and Meta-analysis (CARDIoGRAM) dataset, a meta-analysis comprising genome-wide SNP association data from 22,233 CAD cases and 64,762 controls. 24 out of 41 (58.5 %) risk alleles for celiac disease displayed a positive association with CAD (CAD-OR range 1.001-1.081). The remaining risk alleles for celiac disease (n = 16) revealed CAD-ORs of ≤1.0 (range 0.951-1.0). The proportion of CAD associated alleles was greater but did not differ significantly from the proportion of 50 % expected by chance (p = 0.069). One SNP (rs653178 at the SH2B3/ATXN2 locus) displayed study-wise statistically significant association with CAD with directionality consistent effects on celiac disease and CAD. However, the effect of this locus is most likely driven by pleiotropic effects on multiple other diseases. In conclusion, this genetically based approach provided no convincing evidence that SNPs associated with celiac disease contribute to the risk of CAD. Hence, common non-genetic factors may play a more important role explaining the coincidence of these two complex disease conditions.

Relation of Monocyte/High-Density Lipoprotein Cholesterol Ratio with Coronary Artery Disease in Type 2 Diabetes Mellitus.

PubMed

Ya, Gao; Qiu, Zhang; Tianrong, Pan

2018-06-01

Atherosclerotic cardiovascular disease is the leading cause of mortality of patients with type 2 diabetes mellitus, and both coronary artery disease (CAD) and diabetes mellitus are associated with inflammation. Emerging evidence suggests a relationship of the monocyte to high-density lipoprotein cholesterol ratio (MHR) with the incidence and severity of CAD. The aim of the present study was to examine the association of MHR with CAD in patients with type 2 diabetes mellitus. A total of 458 consecutive individuals were enrolled, comprising 178 type 2 diabetic patients, 124 type 2 diabetes with CAD, and 156 healthy volunteers as the controls. A multivariable logistic regression model was used to evaluate the relationship between the MHR and CAD in type 2 diabetes, and the receiver operating characteristic (ROC) curve of MHR was used for predicting the presence of CAD in type 2 diabetic patients. Values of MHR were significantly higher in type 2 diabetic patients with CAD compared with those without CAD and the control group. Moreover, multivariate logistic regression analysis showed that MHR was an independent predictor of the presence of CAD in type 2 diabetic patients (OR = 1.361, 95% CI 1.245 - 1.487, p < 0.0001). Based on the receiver operating characteristic (ROC) curve, the cutoff value of MHR (> 8.2) in predicting the presence of CAD in type 2 diabetic patients yields a sensitivity and specificity of 83.74% and 62.15%, respectively, with an area under the curve of 0.795 (95% CI: 0.745 - 0.840). The MHR is strongly associated with CAD in type 2 diabetes and might be a potential biomarker to predict the presence of CAD in type 2 diabetic patients.

Genetic polymorphism of matrix metalloproteinase-1 and coronary artery disease susceptibility: a case-control study in a Han Chinese population.

PubMed

Qintao, Cui; Yan, Li; Changhong, Duan; Xiaoliang, Guo; Xiaochen, Liu

2014-12-01

Coronary artery disease (CAD) receives intensive research due to its high incidence and severe impact on the quality of life. One member of the matrix metalloproteinases (MMPs), MMP-1, has been reported to be associated with CAD. To identify the markers contributing to the genetic susceptibility to CAD, nine single-nucleotide polymorphisms (rs1799750, rs498186, rs475007, rs514921, rs494379, rs996999, rs2071232, rs1938901, and rs2239008) throughout the MMP-1 gene were genotyped using MALDI-TOF within the MassARRAY system, and the allele and genotype distributions were compared between 438 healthy controls and 411 patients with CAD from a Chinese Han population. The analysis revealed a weak association between the rs1799750 (in the promoter region) genotype distribution and CAD (p=0.022). An increased risk of CAD was significantly associated with the 2G allele of rs1799750 (p=0.005, odds ratio=1.329, 95% confidence interval=1.090-1.620, after Bonferroni corrections). Strong linkage disequilibrium was observed in three blocks (D'>0.9). Significantly more C-2G (rs498186-rs1799750) haplotypes (p=0.001 after Bonferroni corrections) were found in CAD subjects. These findings point to a role for the polymorphism in the MMP-1 promoter in CAD among a Han Chinese population and may be informative for future genetic or biological studies on CAD.

Impact of background on color, transmittance, and fluorescence of leucite based ceramics.

PubMed

Rafael, Caroline Freitas; Güth, Jan-Frederik; Kauling, Ana Elisa Colle; Cesar, Paulo Francisco; Volpato, Claudia Angelo Mazieiro; Liebermann, Anja

2017-07-26

This study evaluated the impact of tooth shade on differences in color (∆E), lightness (∆L), chromaticity coordinates a*/b* (∆a and ∆b), transmittance and the degree of fluorescence of CAD/CAM leucite based ceramic (LBC). Ten disks were fabricated of LBC; Empress CAD, A2, thickness of 1.5 mm and eight disks of resin-nano-ceramic (RNC; Lava Ultimate) in different colors to simulate variations in substrate shade. The associations of LBC disks with different color substrates were analyzed with a spectrophotometer; ∆E, ∆L*, ∆a*, ∆b*, and transmittance were measured and calculated. Fluorescence was evaluated with a fluorescence system (Fluorescence System, Biopdi). All substrate shades influenced the optical properties of LBC, with regard to color, luminosity, coordinate a* and b*, transmittance, and fluorescence (p<0.001). Substrate colors with high saturation (A3.5 and C2) presented highest impact, whereas colors with lowest saturations (BL, B1) showed less impact. Substrate color influenced the optical properties of ceramic restorations.

AutoCAD-To-NASTRAN Translator Program

NASA Technical Reports Server (NTRS)

Jones, A.

1989-01-01

Program facilitates creation of finite-element mathematical models from geometric entities. AutoCAD to NASTRAN translator (ACTON) computer program developed to facilitate quick generation of small finite-element mathematical models for use with NASTRAN finite-element modeling program. Reads geometric data of drawing from Data Exchange File (DXF) used in AutoCAD and other PC-based drafting programs. Written in Microsoft Quick-Basic (Version 2.0).

Applying a 2D based CAD scheme for detecting micro-calcification clusters using digital breast tomosynthesis images: an assessment

NASA Astrophysics Data System (ADS)

Park, Sang Cheol; Zheng, Bin; Wang, Xiao-Hui; Gur, David

2008-03-01

Digital breast tomosynthesis (DBT) has emerged as a promising imaging modality for screening mammography. However, visually detecting micro-calcification clusters depicted on DBT images is a difficult task. Computer-aided detection (CAD) schemes for detecting micro-calcification clusters depicted on mammograms can achieve high performance and the use of CAD results can assist radiologists in detecting subtle micro-calcification clusters. In this study, we compared the performance of an available 2D based CAD scheme with one that includes a new grouping and scoring method when applied to both projection and reconstructed DBT images. We selected a dataset involving 96 DBT examinations acquired on 45 women. Each DBT image set included 11 low dose projection images and a varying number of reconstructed image slices ranging from 18 to 87. In this dataset 20 true-positive micro-calcification clusters were visually detected on the projection images and 40 were visually detected on the reconstructed images, respectively. We first applied the CAD scheme that was previously developed in our laboratory to the DBT dataset. We then tested a new grouping method that defines an independent cluster by grouping the same cluster detected on different projection or reconstructed images. We then compared four scoring methods to assess the CAD performance. The maximum sensitivity level observed for the different grouping and scoring methods were 70% and 88% for the projection and reconstructed images with a maximum false-positive rate of 4.0 and 15.9 per examination, respectively. This preliminary study demonstrates that (1) among the maximum, the minimum or the average CAD generated scores, using the maximum score of the grouped cluster regions achieved the highest performance level, (2) the histogram based scoring method is reasonably effective in reducing false-positive detections on the projection images but the overall CAD sensitivity is lower due to lower signal-to-noise ratio, and (3) CAD achieved higher sensitivity and higher false-positive rate (per examination) on the reconstructed images. We concluded that without changing the detection threshold or performing pre-filtering to possibly increase detection sensitivity, current CAD schemes developed and optimized for 2D mammograms perform relatively poorly and need to be re-optimized using DBT datasets and new grouping and scoring methods need to be incorporated into the schemes if these are to be used on the DBT examinations.

Initial versus final fracture of metal-free crowns, analyzed via acoustic emission.

PubMed

Ereifej, Nadia; Silikas, Nick; Watts, David C

2008-09-01

To discriminate between initial and final fracture failure loads of four metal-free crown systems by the conjoint detection of acoustic emission signals during compressive loading. Teeth were prepared and used for crown construction with four crown systems; Vita Mark II (VM II) (Vita Zahnfabrik), IPS e.max Ceram/CAD (CAD) (Ivoclar-Vivadent), IPS e.max Ceram/ZirCAD (ZirCAD) (Ivoclar-Vivadent) and BelleGlass/EverStick (BGES) (Kerr/Stick Tech Ltd.). All samples were loaded in compression via a Co/Cr maxillary first molar tooth at 0.2mm/min and released acoustic signals were collected and analyzed. A minimum number of 15 crowns per group were loaded to final failure and values of loading at initial and final fracture were compared. Additional four samples per group were loaded till fracture initiation and were fractographically examined under the optical microscope. A lower threshold of 50dB was selected to exclude spurious background signals. Initial fracture forces were significantly lower than those of final fracture (p<0.05) in all groups and initial failure AE amplitudes were lower than those of final fracture. Mean initial fracture force of ZirCAD samples (1029.1N) was higher than those of VMII (744.4N), CAD (808.8 N) and BGES (979.7 N). Final fracture of ZirCAD also occurred at significantly higher force values (2091.7 N) than the rest of the groups; VMII (1120.9 N), CAD (1468.9 N) and BGES (1576.6 N). Significantly higher values of initial failure AE amplitude were found in VMII than CAD and BGES while those of final fracture were similar. All crowns observed under the microscope at initial fracture had signs of failure. Whereas the metal-free crowns examined showed significant variations in final failure loads, acoustic emission data showed that they all manifested initial failures at significantly lower load values.

Effectiveness and efficiency of a CAD/CAM orthodontic bracket system.

PubMed

Brown, Matthew W; Koroluk, Lorne; Ko, Ching-Chang; Zhang, Kai; Chen, Mengqi; Nguyen, Tung

2015-12-01

The first straight-wire appliance was introduced over 40 years ago to increase the consistency and efficiency of orthodontic treatment. More recently, computer-aided design and computer-aided manufacturing (CAD/CAM) technology has been used to create individualized orthodontic appliances. The purpose of this study was to investigate the clinical effectiveness and efficiency of CAD/CAM customized orthodontic appliances compared with direct and indirect bonded stock orthodontic brackets. This retrospective study included 3 treatment groups: group 1 patients were direct bonded with self-ligating appliances, group 2 patients were indirect bonded with self-ligating appliances, and group 3 patients were indirect bonded with CAD/CAM self-ligating appliances. Complete pretreatment and posttreatment records were obtained for all patients. The American Board of Orthodontics (ABO) Discrepancy Index was used to evaluate the pretreatment records, and the posttreatment outcomes were analyzed using the ABO Cast-Radiograph Evaluation. All data collection and analysis were completed by 1 evaluator. There were no statistically significant differences in the ABO Discrepancy Index or the ABO Cast-Radiograph Evaluation among the groups. Treatment times for the 3 groups were significantly different; the CAD/CAM group was the shortest at 13.8 ± 3.4 months, compared with 21.9 ± 5.0 and 16.9 ± 4.1 months for the direct bonded and indirect bonded groups, respectively. The number of treatment appointments for the CAD/CAM group was significantly fewer than for the direct bonded group. The CAD/CAM orthodontic bracket system evaluated in this study was as effective in treatment outcome measures as were standard brackets bonded both directly and indirectly. The CAD/CAM appliance was more efficient in regard to treatment duration, although the decrease in total archwire appointments was minimal. Further investigation is needed to better quantify the clinical benefits of CAD/CAM orthodontic appliances. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Precision Fit of Screw-Retained Implant-Supported Fixed Dental Prostheses Fabricated by CAD/CAM, Copy-Milling, and Conventional Methods.

PubMed

de França, Danilo Gonzaga; Morais, Maria Helena; das Neves, Flávio D; Carreiro, Adriana Fonte; Barbosa, Gustavo As

The aim of this study was to evaluate the effectiveness of fabrication methods (computer-aided design/computer-aided manufacture [CAD/CAM], copy-milling, and conventional casting) in the fit accuracy of three-unit, screw-retained fixed dental prostheses. Sixteen three-unit implant-supported screw-retained frameworks were fabricated to fit an in vitro model. Eight frameworks were fabricated using the CAD/CAM system, four in zirconia and four in cobalt-chromium. Four zirconia frameworks were fabricated using the copy-milled system, and four were cast in cobalt-chromium using conventional casting with premachined abutments. The vertical and horizontal misfit at the implant-framework interface was measured using scanning electron microscopy at ×250. The results for vertical misfit were analyzed using Kruskal-Wallis and Mann-Whitney tests. The horizontal misfits were categorized as underextended, equally extended, or overextended. Statistical analysis established differences between groups according to the chi-square test (α = .05). The mean vertical misfit was 5.9 ± 3.6 μm for CAD/CAM-fabricated zirconia, 1.2 ± 2.2 μm for CAD/CAM-fabricated cobalt-chromium frameworks, 7.6 ± 9.2 μm for copy-milling-fabricated zirconia frameworks, and 11.8 (9.8) μm for conventionally fabricated frameworks. The Mann-Whitney test revealed significant differences between all but the zirconia-fabricated frameworks. A significant association was observed between the horizontal misfits and the fabrication method. The percentage of horizontal misfits that were underextended and overextended was higher in milled zirconia (83.3%), CAD/CAM cobaltchromium (66.7%), cast cobalt-chromium (58.3%), and CAD/CAM zirconia (33.3%) frameworks. CAD/CAM-fabricated frameworks exhibit better vertical misfit and low variability compared with copy-milled and conventionally fabricated frameworks. The percentage of interfaces equally extended was higher when CAD/CAM and zirconia were used.

Comparison of denture tooth movement between CAD-CAM and conventional fabrication techniques.

PubMed

Goodacre, Brian J; Goodacre, Charles J; Baba, Nadim Z; Kattadiyil, Mathew T

2018-01-01

Data comparing the denture tooth movement of computer-aided design and computer-aided manufacturing (CAD-CAM) and conventional denture processing techniques are lacking. The purpose of this in vitro study was to compare the denture tooth movement of pack-and-press, fluid resin, injection, CAD-CAM-bonded, and CAD-CAM monolithic techniques for fabricating dentures to determine which process produces the most accurate and reproducible prosthesis. A total of 50 dentures were evaluated, 10 for each of the 5 groups. A master denture was fabricated and milled from prepolymerized poly(methyl methacrylate). For the conventional processing techniques (pack-and-press, fluid resin, and injection) a polyvinyl siloxane putty mold of the master denture was made in which denture teeth were placed and molten wax injected. The cameo surface of each wax-festooned denture was laser scanned, resulting in a standard tessellation language (STL) format file. The CAD-CAM dentures included 2 subgroups: CAD-CAM-bonded teeth in which the denture teeth were bonded into the milled denture base and CAD-CAM monolithic teeth in which the denture teeth were milled as part of the denture base. After all specimens had been fabricated, they were hydrated for 24 hours, and the cameo surface laser scanned. The preprocessing and postprocessing scan files of each denture were superimposed using surface-matching software. Measurements were made at 64 locations, allowing evaluation of denture tooth movement in a buccal, lingual, mesial-distal, and occlusal direction. The use of median and interquartile range values was used to assess accuracy and reproducibility. Levene and Kruskal-Wallis analyses of variance were used to evaluate differences between processing techniques (α=.05). The CAD-CAM monolithic technique was the most accurate, followed by fluid resin, CAD-CAM-bonded, pack-and-press, and injection. CAD-CAM monolithic technique was the most reproducible, followed by pack-and-press, CAD-CAM-bonded, injection, and fluid resin. Techniques involving compression during processing showed increased positive occlusal tooth movement compared with techniques not involving compression. CAD-CAM monolithic dentures produced the best combination of accuracy and reproducibility of the tested techniques. The results from this study demonstrate that varying amounts of tooth movement can be expected depending on the processing technique. However, the clinical significance of these differences is unknown. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Verifying Three-Dimensional Skull Model Reconstruction Using Cranial Index of Symmetry

PubMed Central

Kung, Woon-Man; Chen, Shuo-Tsung; Lin, Chung-Hsiang; Lu, Yu-Mei; Chen, Tzu-Hsuan; Lin, Muh-Shi

2013-01-01

Background Difficulty exists in scalp adaptation for cranioplasty with customized computer-assisted design/manufacturing (CAD/CAM) implant in situations of excessive wound tension and sub-cranioplasty dead space. To solve this clinical problem, the CAD/CAM technique should include algorithms to reconstruct a depressed contour to cover the skull defect. Satisfactory CAM-derived alloplastic implants are based on highly accurate three-dimensional (3-D) CAD modeling. Thus, it is quite important to establish a symmetrically regular CAD/CAM reconstruction prior to depressing the contour. The purpose of this study is to verify the aesthetic outcomes of CAD models with regular contours using cranial index of symmetry (CIS). Materials and methods From January 2011 to June 2012, decompressive craniectomy (DC) was performed for 15 consecutive patients in our institute. 3-D CAD models of skull defects were reconstructed using commercial software. These models were checked in terms of symmetry by CIS scores. Results CIS scores of CAD reconstructions were 99.24±0.004% (range 98.47–99.84). CIS scores of these CAD models were statistically significantly greater than 95%, identical to 99.5%, but lower than 99.6% (p<0.001, p = 0.064, p = 0.021 respectively, Wilcoxon matched pairs signed rank test). These data evidenced the highly accurate symmetry of these CAD models with regular contours. Conclusions CIS calculation is beneficial to assess aesthetic outcomes of CAD-reconstructed skulls in terms of cranial symmetry. This enables further accurate CAD models and CAM cranial implants with depressed contours, which are essential in patients with difficult scalp adaptation. PMID:24204566

A distributed data base management facility for the CAD/CAM environment

NASA Technical Reports Server (NTRS)

Balza, R. M.; Beaudet, R. W.; Johnson, H. R.

1984-01-01

Current/PAD research in the area of distributed data base management considers facilities for supporting CAD/CAM data management in a heterogeneous network of computers encompassing multiple data base managers supporting a variety of data models. These facilities include coordinated execution of multiple DBMSs to provide for administration of and access to data distributed across them.

Computerized breast cancer analysis system using three stage semi-supervised learning method.

PubMed

Sun, Wenqing; Tseng, Tzu-Liang Bill; Zhang, Jianying; Qian, Wei

2016-10-01

A large number of labeled medical image data is usually a requirement to train a well-performed computer-aided detection (CAD) system. But the process of data labeling is time consuming, and potential ethical and logistical problems may also present complications. As a result, incorporating unlabeled data into CAD system can be a feasible way to combat these obstacles. In this study we developed a three stage semi-supervised learning (SSL) scheme that combines a small amount of labeled data and larger amount of unlabeled data. The scheme was modified on our existing CAD system using the following three stages: data weighing, feature selection, and newly proposed dividing co-training data labeling algorithm. Global density asymmetry features were incorporated to the feature pool to reduce the false positive rate. Area under the curve (AUC) and accuracy were computed using 10 fold cross validation method to evaluate the performance of our CAD system. The image dataset includes mammograms from 400 women who underwent routine screening examinations, and each pair contains either two cranio-caudal (CC) or two mediolateral-oblique (MLO) view mammograms from the right and the left breasts. From these mammograms 512 regions were extracted and used in this study, and among them 90 regions were treated as labeled while the rest were treated as unlabeled. Using our proposed scheme, the highest AUC observed in our research was 0.841, which included the 90 labeled data and all the unlabeled data. It was 7.4% higher than using labeled data only. With the increasing amount of labeled data, AUC difference between using mixed data and using labeled data only reached its peak when the amount of labeled data was around 60. This study demonstrated that our proposed three stage semi-supervised learning can improve the CAD performance by incorporating unlabeled data. Using unlabeled data is promising in computerized cancer research and may have a significant impact for future CAD system applications. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Computer-Based Technologies in Dentistry: Types and Applications

PubMed Central

Albuha Al-Mussawi, Raja’a M.; Farid, Farzaneh

2016-01-01

During dental education, dental students learn how to examine patients, make diagnosis, plan treatment and perform dental procedures perfectly and efficiently. However, progresses in computer-based technologies including virtual reality (VR) simulators, augmented reality (AR) and computer aided design/computer aided manufacturing (CAD/CAM) systems have resulted in new modalities for instruction and practice of dentistry. Virtual reality dental simulators enable repeated, objective and assessable practice in various controlled situations. Superimposition of three-dimensional (3D) virtual images on actual images in AR allows surgeons to simultaneously visualize the surgical site and superimpose informative 3D images of invisible regions on the surgical site to serve as a guide. The use of CAD/CAM systems for designing and manufacturing of dental appliances and prostheses has been well established. This article reviews computer-based technologies, their application in dentistry and their potentials and limitations in promoting dental education, training and practice. Practitioners will be able to choose from a broader spectrum of options in their field of practice by becoming familiar with new modalities of training and practice. PMID:28392819

Computer-Based Technologies in Dentistry: Types and Applications.

PubMed

Albuha Al-Mussawi, Raja'a M; Farid, Farzaneh

2016-06-01

During dental education, dental students learn how to examine patients, make diagnosis, plan treatment and perform dental procedures perfectly and efficiently. However, progresses in computer-based technologies including virtual reality (VR) simulators, augmented reality (AR) and computer aided design/computer aided manufacturing (CAD/CAM) systems have resulted in new modalities for instruction and practice of dentistry. Virtual reality dental simulators enable repeated, objective and assessable practice in various controlled situations. Superimposition of three-dimensional (3D) virtual images on actual images in AR allows surgeons to simultaneously visualize the surgical site and superimpose informative 3D images of invisible regions on the surgical site to serve as a guide. The use of CAD/CAM systems for designing and manufacturing of dental appliances and prostheses has been well established. This article reviews computer-based technologies, their application in dentistry and their potentials and limitations in promoting dental education, training and practice. Practitioners will be able to choose from a broader spectrum of options in their field of practice by becoming familiar with new modalities of training and practice.

Comparison between five CAD/CAM systems for fit of zirconia copings.

PubMed

Habib, Syed Rashid; Al Otaibi, Asim Khaled; Al Anazi, Talal Ali; Al Anazi, Samer Mosleh

2018-01-01

The aim of this in-vitro study was to investigate the marginal and internal fit of zirconia copings fabricated by five CAD/CAM (computer-aided design/computer-assisted manufacture) systems. A typodont mandibular right first molar was prepared according to ideal parameters for a zirconia crown, scanned digitally, and 100 identical resin dies fabricated by 3D printing. Samples were randomly divided into five groups and sent to CAD/CAM systems for zirconia copings (A, Ceramill-Motion 2, Amann Girrbach; B, Weiland, Ivoclar Vivadent; C, Cerec, Ivoclar Vivadent; D, Prettau Zirconia, Zirkonzahn; E, Cad4dent). CAD of the copings included standardized cement space of 30 µm and CAM was carried out. Copings were tried/adjusted on the respective dies and embedded under a standardized load of 20 N in self-curing resin. Samples were sectioned mesiodistally into two halves. Marginal and internal gap values were measured with a digital microscope at 50 to 200 × magnification at nine sites. The lowest and highest mean gap values of 46.93 ± 13.50 and 101.65 ± 35.56 μm were found for Group A and Group D, respectively. ANOVA showed a statistically significant difference between the mean values of all the groups (P = .000). Multiple comparisons with post hoc Tukey test indicated a statistically significant difference (P < .05) between: Group A and all groups except B; B with D; C with A; D with A; and B and E with A. Mean buccal/lingual gap value was found to be 51.54 ± 58.54 μm. Of the nine sites, the least gap resulted at the buccal axial wall and the greatest at the central groove. The overall mean gap recorded for the copings was 72.43 ± 57.56 μm. Marginal and internal adaptations of CAD/CAM zirconia copings is influenced by manufacturing technique, and variations exist for different systems. Measurement sites showed different levels. CAD/CAM systems investigated showed a clinically acceptable level of gap values (< 120 µm).

Effects of physical activity and exercise training on cardiovascular risk in coronary artery disease patients with and without type 2 diabetes.

PubMed

Karjalainen, Jaana J; Kiviniemi, Antti M; Hautala, Arto J; Piira, Olli-Pekka; Lepojärvi, E Samuli; Perkiömäki, Juha S; Junttila, M Juhani; Huikuri, Heikki V; Tulppo, Mikko P

2015-04-01

Leisure-time physical activity (LTPA) and exercise training are essential parts of current guidelines for patients with coronary artery disease (CAD). However, the contributions of LTPA and exercise training to cardiovascular (CV) risk in CAD patients with type 2 diabetes (T2D) are not well established. We examined the effects of LTPA (n = 539 and n = 507; with and without T2D, respectively) and 2-year controlled, home-based exercise training (n = 63 plus 64 control subjects with T2D and n = 72 plus 68 control subjects without T2D) on the CV risk profile and composite end point among CAD patients. During the 2-year follow-up, patients with reduced LTPA at baseline had an increased risk of CV events (adjusted hazard ratio 2.3 [95% CI 1.1-5.1; P = 0.033], 2.1 [1.1-4.2; P = 0.027], and 2.0 [1.0-3.9; P = 0.044] for no LTPA, LTPA irregularly, and LTPA two to three times weekly, respectively) compared with those with LTPA more than three times weekly. Among patients who completed the 2-year exercise intervention, exercise training resulted in favorable changes in exercise capacity both in CAD patients with T2D (+0.2 ± 0.8 vs. -0.1 ± 0.8 MET, P = 0.030) and without T2D (+0.3 ± 0.7 vs. -0.1 ± 0.5 MET, P = 0.002) as compared with the control group but did not have any significant effects on major metabolic or autonomic nervous system risk factors in CAD patients with or without T2D. There is an inverse association between habitual LTPA and short-term CV outcome, but controlled, home-based exercise training has only minor effects on the CV risk profile in CAD patients with T2D. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Direct costs and cost-effectiveness of dual-source computed tomography and invasive coronary angiography in patients with an intermediate pretest likelihood for coronary artery disease.

PubMed

Dorenkamp, Marc; Bonaventura, Klaus; Sohns, Christian; Becker, Christoph R; Leber, Alexander W

2012-03-01

The study aims to determine the direct costs and comparative cost-effectiveness of latest-generation dual-source computed tomography (DSCT) and invasive coronary angiography for diagnosing coronary artery disease (CAD) in patients suspected of having this disease. The study was based on a previously elaborated cohort with an intermediate pretest likelihood for CAD and on complementary clinical data. Cost calculations were based on a detailed analysis of direct costs, and generally accepted accounting principles were applied. Based on Bayes' theorem, a mathematical model was used to compare the cost-effectiveness of both diagnostic approaches. Total costs included direct costs, induced costs and costs of complications. Effectiveness was defined as the ability of a diagnostic test to accurately identify a patient with CAD. Direct costs amounted to €98.60 for DSCT and to €317.75 for invasive coronary angiography. Analysis of model calculations indicated that cost-effectiveness grew hyperbolically with increasing prevalence of CAD. Given the prevalence of CAD in the study cohort (24%), DSCT was found to be more cost-effective than invasive coronary angiography (€970 vs €1354 for one patient correctly diagnosed as having CAD). At a disease prevalence of 49%, DSCT and invasive angiography were equally effective with costs of €633. Above a threshold value of disease prevalence of 55%, proceeding directly to invasive coronary angiography was more cost-effective than DSCT. With proper patient selection and consideration of disease prevalence, DSCT coronary angiography is cost-effective for diagnosing CAD in patients with an intermediate pretest likelihood for it. However, the range of eligible patients may be smaller than previously reported.

A charged aerosol detector/chemiluminescent nitrogen detector/liquid chromatography/mass spectrometry system for regular and fragment compound analysis in drug discovery.

PubMed

Jiang, Yutao; Hascall, Daniel; Li, Delia; Pease, Joseph H

2015-09-11

In this paper, we introduce a high throughput LCMS/UV/CAD/CLND system that improves upon previously reported systems by increasing both the quantitation accuracy and the range of compounds amenable to testing, in particular, low molecular weight "fragment" compounds. This system consists of a charged aerosol detector (CAD) and chemiluminescent nitrogen detector (CLND) added to a LCMS/UV system. Our results show that the addition of CAD and CLND to LCMS/UV is more reliable for concentration determination for a wider range of compounds than either detector alone. Our setup also allows for the parallel analysis of each sample by all four detectors and so does not significantly increase run time per sample. Copyright © 2015 Elsevier B.V. All rights reserved.

Computer aided diagnosis based on medical image processing and artificial intelligence methods

NASA Astrophysics Data System (ADS)

Stoitsis, John; Valavanis, Ioannis; Mougiakakou, Stavroula G.; Golemati, Spyretta; Nikita, Alexandra; Nikita, Konstantina S.

2006-12-01

Advances in imaging technology and computer science have greatly enhanced interpretation of medical images, and contributed to early diagnosis. The typical architecture of a Computer Aided Diagnosis (CAD) system includes image pre-processing, definition of region(s) of interest, features extraction and selection, and classification. In this paper, the principles of CAD systems design and development are demonstrated by means of two examples. The first one focuses on the differentiation between symptomatic and asymptomatic carotid atheromatous plaques. For each plaque, a vector of texture and motion features was estimated, which was then reduced to the most robust ones by means of ANalysis of VAriance (ANOVA). Using fuzzy c-means, the features were then clustered into two classes. Clustering performances of 74%, 79%, and 84% were achieved for texture only, motion only, and combinations of texture and motion features, respectively. The second CAD system presented in this paper supports the diagnosis of focal liver lesions and is able to characterize liver tissue from Computed Tomography (CT) images as normal, hepatic cyst, hemangioma, and hepatocellular carcinoma. Five texture feature sets were extracted for each lesion, while a genetic algorithm based feature selection method was applied to identify the most robust features. The selected feature set was fed into an ensemble of neural network classifiers. The achieved classification performance was 100%, 93.75% and 90.63% in the training, validation and testing set, respectively. It is concluded that computerized analysis of medical images in combination with artificial intelligence can be used in clinical practice and may contribute to more efficient diagnosis.

Defense AT&L (Volume 36, Number 5, September-October 2007)

DTIC Science & Technology

2007-10-01

requirements, providing security solutions, and manag- ing the security of information systems. 14 CAD/ PAD Require- ments Determination in the Air Force...be contacted at williams_peter@bah.com and steward_tiffani@bah.com. Defense AT&L: September-October 2007 14 Williams is director of the CAD/ PAD Joint...the U.S. House Science and Technology Subcommittee on Transportation, Aviation and Materials. Blair is the former head of the Air Force CAD/ PAD

SU-E-I-30: Image Analysis in Ultrasonography for Diagnosis of Sjoegren's Syndrome Using Dual-Tree Complex Wavelet Transform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsui, T; Ohki, M; Nakamura, T

Purpose: Sjoegren's syndrome (SS) is an autoimmune disease invading mainly salivary and lacrimal glands. Ultrasonography is used for an initial and non-invasive examination of this disease. However, the ultrasonography diagnosis tends to lack in objectivity and depends on the operator's skills. The purpose of this study is to propose a computer-aided diagnosis (CAD) system for SS based on a dual-tree complex wavelet transform (DT-CWT) and machine learning. Methods: The subjects of this study were 174 patients suspected of having SS at Nagasaki University Hospital and examined with ultrasonography of the parotid glands. Out of these patients, 77 patients were diagnosedmore » with SS by sialography. A region of interest (ROI) of 128 × 128 pixels was set within the parotid gland that was indicated by a dental radiologist. The DT-CWT was applied to the images in the ROI and every image was decomposed into 72 sub-images of the real and imaginary components in six different resolution levels and six orientations. The statistical features of the sub-image were calculated and used as data input for the support vector machine (SVM) classifier for the detection of SS. A ten-fold cross-validation was employed to verify the Resultof SVM. The accuracy of diagnosis was compared by a CAD system with a human observer performance. Results: The sensitivity, specificity, and accuracy in the detection of SS were 95%, 86%, and 91% through our CAD system respectively, while those by a human observer were 84%, 81%, and 83% respectively. Conclusion: The proposed computer-aided diagnosis system for Sjoegren's syndrome in ultrasonography based on dual-tree complex wavelet transform had a better performance than a human observer.« less

ADMultiImg: a novel missing modality transfer learning based CAD system for diagnosis of MCI due to AD using incomplete multi-modality imaging data

NASA Astrophysics Data System (ADS)

Liu, Xiaonan; Chen, Kewei; Wu, Teresa; Weidman, David; Lure, Fleming; Li, Jing

2018-02-01

Alzheimer's Disease (AD) is the most common cause of dementia and currently has no cure. Treatments targeting early stages of AD such as Mild Cognitive Impairment (MCI) may be most effective to deaccelerate AD, thus attracting increasing attention. However, MCI has substantial heterogeneity in that it can be caused by various underlying conditions, not only AD. To detect MCI due to AD, NIA-AA published updated consensus criteria in 2011, in which the use of multi-modality images was highlighted as one of the most promising methods. It is of great interest to develop a CAD system based on automatic, quantitative analysis of multi-modality images and machine learning algorithms to help physicians more adequately diagnose MCI due to AD. The challenge, however, is that multi-modality images are not universally available for many patients due to cost, access, safety, and lack of consent. We developed a novel Missing Modality Transfer Learning (MMTL) algorithm capable of utilizing whatever imaging modalities are available for an MCI patient to diagnose the patient's likelihood of MCI due to AD. Furthermore, we integrated MMTL with radiomics steps including image processing, feature extraction, and feature screening, and a post-processing for uncertainty quantification (UQ), and developed a CAD system called "ADMultiImg" to assist clinical diagnosis of MCI due to AD using multi-modality images together with patient demographic and genetic information. Tested on ADNI date, our system can generate a diagnosis with high accuracy even for patients with only partially available image modalities (AUC=0.94), and therefore may have broad clinical utility.

Developing Customized Dental Miniscrew Surgical Template from Thermoplastic Polymer Material Using Image Superimposition, CAD System, and 3D Printing

PubMed Central

Yu, Jian-Hong; Lo, Lun-Jou; Hsu, Pin-Hsin

2017-01-01

This study integrates cone-beam computed tomography (CBCT)/laser scan image superposition, computer-aided design (CAD), and 3D printing (3DP) to develop a technology for producing customized dental (orthodontic) miniscrew surgical templates using polymer material. Maxillary bone solid models with the bone and teeth reconstructed using CBCT images and teeth and mucosa outer profile acquired using laser scanning were superimposed to allow miniscrew visual insertion planning and permit surgical template fabrication. The customized surgical template CAD model was fabricated offset based on the teeth/mucosa/bracket contour profiles in the superimposition model and exported to duplicate the plastic template using the 3DP technique and polymer material. An anterior retraction and intrusion clinical test for the maxillary canines/incisors showed that two miniscrews were placed safely and did not produce inflammation or other discomfort symptoms one week after surgery. The fitness between the mucosa and template indicated that the average gap sizes were found smaller than 0.5 mm and confirmed that the surgical template presented good holding power and well-fitting adaption. This study addressed integrating CBCT and laser scan image superposition; CAD and 3DP techniques can be applied to fabricate an accurate customized surgical template for dental orthodontic miniscrews. PMID:28280726

Overview of NASA MSFC IEC Multi-CAD Collaboration Capability

NASA Technical Reports Server (NTRS)

Moushon, Brian; McDuffee, Patrick

2005-01-01

This viewgraph presentation provides an overview of a Design and Data Management System (DDMS) for Computer Aided Design (CAD) collaboration in order to support the Integrated Engineering Capability (IEC) at Marshall Space Flight Center (MSFC).

Video display engineering and optimization system

NASA Technical Reports Server (NTRS)

Larimer, James (Inventor)

1997-01-01

A video display engineering and optimization CAD simulation system for designing a LCD display integrates models of a display device circuit, electro-optics, surface geometry, and physiological optics to model the system performance of a display. This CAD system permits system performance and design trade-offs to be evaluated without constructing a physical prototype of the device. The systems includes a series of modules which permit analysis of design trade-offs in terms of their visual impact on a viewer looking at a display.

Evaluation of association between common genetic variants on chromosome 9p21 and coronary artery disease in Turkish population.

PubMed

Çakmak, Hüseyin Altuğ; Bayoğlu, Burcu; Durmaz, Eser; Can, Günay; Karadağ, Bilgehan; Cengiz, Müjgan; Vural, Vural Ali; Yüksel, Hüsniye

2015-03-01

Coronary artery disease (CAD), which develops from complex interactions between genetic and enviromental factors, is a leading cause of death worldwide. Based on genome-wide association studies (GWAS), the chromosomal region 9p21 has been identified as the most relevant locus presenting a strong association with CAD in different populations. The aim of the present study was to investigate the association of two SNPs on chromosome 9p21 on susceptibility to CAD and the effect of these SNPs along with cardiovascular risk factors on the severity of CAD in the Turkish population. This study had an observational case-control design. We genotyped 460 subjects, aged 30-65 years, to investigate the association of 2 SNPs (rs1333049, rs2383207) on chromosome 9p21 and CAD risk in Turkish population. Real-time polymerase chain reaction (RT-PCR) was used to analyze the 2 SNPs in CAD patients and healthy controls. The genotype and allelic variations of these SNPs with the severity of CAD was also assessed using semi-quantitative methods such as the Gensini score. Student's t test and multiple regression analysis were used for statistical analysis. The SNPs rs1333049 and rs2383207 were found to be associated with CAD with an adjusted OR of 1.81 (95% Cl 1.05-3.12) and 2.12 (95% CI 1.19-4.10) respectively. After adjustment of CAD risk factors such as smoking, family history of CAD and diabetes, the homozygous AA genotype for rs2383207 increased the CAD risk with an OR 3.69. Also a very strong association was found between rs1333049 and rs2383207 and Gensini scores representing the severity of CAD (p<0.001). The rs2383207 and rs1333049 SNPs on 9p21 chromosome were significantly associated with the risk and severity of CAD in the Turkish population.

Classification of Computer-Aided Design-Computer-Aided Manufacturing Applications for the Reconstruction of Cranio-Maxillo-Facial Defects.

PubMed

Wauters, Lauri D J; Miguel-Moragas, Joan San; Mommaerts, Maurice Y

2015-11-01

To gain insight into the methodology of different computer-aided design-computer-aided manufacturing (CAD-CAM) applications for the reconstruction of cranio-maxillo-facial (CMF) defects. We reviewed and analyzed the available literature pertaining to CAD-CAM for use in CMF reconstruction. We proposed a classification system of the techniques of implant and cutting, drilling, and/or guiding template design and manufacturing. The system consisted of 4 classes (I-IV). These classes combine techniques used for both the implant and template to most accurately describe the methodology used. Our classification system can be widely applied. It should facilitate communication and immediate understanding of the methodology of CAD-CAM applications for the reconstruction of CMF defects.

Identification of the CAD gene from Eucalyptus urophylla GLU4 and its functional analysis in transgenic tobacco.

PubMed

Chen, B W; Xiao, Y F; Li, J J; Liu, H L; Qin, Z H; Gai, Y; Jiang, X N

2016-12-02

Cinnamyl alcohol dehydrogenase (CAD) catalyzes the final step in lignin biosynthesis. The genus Eucalyptus belongs to the family Myrtaceae, which is the main cultivated species in China. Eucalyptus urophylla GLU4 (GLU4) is widely grown in Guangxi. It is preferred for pulping because of its excellent cellulose content and fiber length. Based on GLU4 and CAD gene expression, a Eucalyptus variety low in lignin content should be obtained using transgenic technology, which could reduce the cost of pulp and improve the pulping rate, and have favorable prospects for application. However, the role and function of CAD in GLU4 is still unclear. In the present study, EuCAD was cloned from GLU4 and identified using bioinformatic tools. Subsequently, in order to evaluate its impact on lignin synthesis, a full-length EuCAD RNAi vector was constructed, and transgenic tobacco was obtained via Agrobacterium-mediated transformation. A significant decrease in CAD expression and lignin content in transgenic tobacco demonstrated a key role for EuCAD in lignin biosynthesis and established a regulatory role for RNAi. In our study, the direct molecular basis of EuCAD expression was determined, and the potential regulatory effects of this RNAi vector on lignin biosynthesis in E. urophylla GLU4 were demonstrated. Our results provide a theoretical basis for the study of lignin biosynthesis in Eucalyptus.

Effect of CALIPSO Cloud Aerosol Discrimination (CAD) Confidence Levels on Observations of Aerosol Properties near Clouds

NASA Technical Reports Server (NTRS)

Yang, Weidong; Marshak, Alexander; Varnai, Tamas; Liu, Zhaoyan

2012-01-01

CALIPSO aerosol backscatter enhancement in the transition zone between clouds and clear sky areas is revisited with particular attention to effects of data selection based on the confidence level of cloud-aerosol discrimination (CAD). The results show that backscatter behavior in the transition zone strongly depends on the CAD confidence level. Higher confidence level data has a flatter backscatter far away from clouds and a much sharper increase near clouds (within 4 km), thus a smaller transition zone. For high confidence level data it is shown that the overall backscatter enhancement is more pronounced for small clear-air segments and horizontally larger clouds. The results suggest that data selection based on CAD reduces the possible effects of cloud contamination when studying aerosol properties in the vicinity of clouds.

Clinical pharmacy cardiac risk service for managing patients with coronary artery disease in a health maintenance organization.

PubMed

Sandhoff, Brian G; Nies, Leslie K; Olson, Kari L; Nash, James D; Rasmussen, Jon R; Merenich, John A

2007-01-01

A clinical pharmacy service for managing the treatment of coronary artery disease in a health maintenance organization is described. Despite the proven benefits of aggressive risk factor modification for patients with coronary artery disease (CAD), there remains a treatment gap between consensus- and evidence-based recommendations and their application in patient care. In 1998, Kaiser Permanente of Colorado developed the Clinical Pharmacy Cardiac Risk Service (CPCRS) to focus on the long-term management of patients with CAD to improve clinical outcomes. The primary goals of the CPCRS are to increase the number of CAD patients on lipid-lowering therapy, manage medications shown to decrease the risk of future CAD-related events, assist in the monitoring and control of other diseases that increase cardiovascular risk, provide patient education and recommendations for nonpharmacologic therapy, and act as a CAD information resource for physicians and other health care providers. Using an electronic medical record and tracking database, the service works in close collaboration with primary care physicians, cardiologists, cardiac rehabilitation nurses, and other health care providers to reduce cardiac risk in the CAD population. Particular attention is given to dyslipidemia, blood pressure, diabetes mellitus, and tobacco cessation. Treatment with evidence-based regimens is initiated and adjusted as necessary. Over 11,000 patients are currently being followed by the CPCRS. A clinical pharmacy service in a large health maintenance organization provides cardiac risk reduction for patients with CAD and helps close treatment gaps that may exist for these patients.

Differential protection of Cry1Fa toxin against Spodoptera frugiperda larval gut proteases by cadherin orthologs correlates with increased synergism.

PubMed

Rahman, Khalidur; Abdullah, Mohd Amir F; Ambati, Suresh; Taylor, Milton D; Adang, Michael J

2012-01-01

The Cry proteins produced by Bacillus thuringiensis (Bt) are the most widely used biopesticides effective against a range of crop pests and disease vectors. Like chemical pesticides, development of resistance is the primary threat to the long-term efficacy of Bt toxins. Recently discovered cadherin-based Bt Cry synergists showed the potential to augment resistance management by improving efficacy of Cry toxins. However, the mode of action of Bt Cry synergists is thus far unclear. Here we elucidate the mechanism of cadherin-based Cry toxin synergism utilizing two cadherin peptides, Spodoptera frugiperda Cad (SfCad) and Manduca sexta Cad (MsCad), which differentially enhance Cry1Fa toxicity to Spodoptera frugiperda neonates. We show that differential SfCad- and MsCad-mediated protection of Cry1Fa toxin in the Spodoptera frugiperda midgut correlates with differential Cry1Fa toxicity enhancement. Both peptides exhibited high affinity for Cry1Fa toxin and an increased rate of Cry1Fa-induced pore formation in S. frugiperda. However, only SfCad bound the S. frugiperda brush border membrane vesicle and more effectively prolonged the stability of Cry1Fa toxin in the gut, explaining higher Cry1Fa enhancement by this peptide. This study shows that cadherin fragments may enhance B. thuringiensis toxicity by at least two different mechanisms or a combination thereof: (i) protection of Cry toxin from protease degradation in the insect midgut and (ii) enhancement of pore-forming ability of Cry toxin.

Utilization of design data on conventional system to building information modeling (BIM)

NASA Astrophysics Data System (ADS)

Akbar, Boyke M.; Z. R., Dewi Larasati

2017-11-01

Nowadays infrastructure development becomes one of the main priorities in the developed country such as Indonesia. The use of conventional design system is considered no longer effectively support the infrastructure projects, especially for the high complexity building design, due to its fragmented system issues. BIM comes as one of the solutions in managing projects in an integrated manner. Despite of the all known BIM benefits, there are some obstacles on the migration process to BIM. The two main of the obstacles are; the BIM implementation unpreparedness of some project parties and a concerns to leave behind the existing database and create a new one on the BIM system. This paper discusses the utilization probabilities of the existing CAD data from the conventional design system for BIM system. The existing conventional CAD data's and BIM design system output was studied to examine compatibility issues between two subject and followed by an utilization scheme-strategy probabilities. The goal of this study is to add project parties' eagerness in migrating to BIM by maximizing the existing data utilization and hopefully could also increase BIM based project workflow quality.

The accuracy of the CAD system using intraoral and extraoral scanners for designing of fixed dental prostheses.

PubMed

Shimizu, Sakura; Shinya, Akikazu; Kuroda, Soichi; Gomi, Harunori

2017-07-26

The accuracy of prostheses affects clinical success and is, in turn, affected by the accuracy of the scanner and CAD programs. Thus, their accuracy is important. The first aim of this study was to evaluate the accuracy of an intraoral scanner with active triangulation (Cerec Omnicam), an intraoral scanner with a confocal laser (3Shape Trios), and an extraoral scanner with active triangulation (D810). The second aim of this study was to compare the accuracy of the digital crowns designed with two different scanner/CAD combinations. The accuracy of the intraoral scanners and extraoral scanner was clinically acceptable. Marginal and internal fit of the digital crowns fabricated using the intraoral scanner and CAD programs were inferior to those fabricated using the extraoral scanner and CAD programs.

Investigation of optimal use of computer-aided detection systems: the role of the "machine" in decision making process.

PubMed

Paquerault, Sophie; Hardy, Paul T; Wersto, Nancy; Chen, John; Smith, Robert C

2010-09-01

The aim of this study was to explore different computerized models (the "machine") as a means to achieve optimal use of computer-aided detection (CAD) systems and to investigate whether these models can play a primary role in clinical decision making and possibly replace a clinician's subjective decision for combining his or her own assessment with that provided by a CAD system. Data previously collected from a fully crossed, multiple-reader, multiple-case observer study with and without CAD by seven observers asked to identify simulated small masses on two separate sets of 100 mammographic images (low-contrast and high-contrast sets; ie, low-contrast and high-contrast simulated masses added to random locations on normal mammograms) were used. This allowed testing two relative sensitivities between the observers and CAD. Seven models that combined detection assessments from CAD standalone, unaided read, and CAD-aided read (second read and concurrent read) were developed using the leave-one-out technique for training and testing. These models were personalized for each observer. Detection performance accuracies were analyzed using the area under a portion of the free-response receiver-operating characteristic curve (AUFC), sensitivity, and number of false-positives per image. For the low-contrast set, the use of computerized models resulted in significantly higher AUFCs compared to the unaided read mode for all readers, whereas the increased AUFCs between CAD-aided (second and concurrent reads; ie, decisions made by the readers) and unaided read modes were statistically significant for a majority, but not all, of the readers (four and five of the seven readers, respectively). For the high-contrast set, there were no significant trends in the AUFCs whether or not a model was used to combine the original reading modes. Similar results were observed when using sensitivity as the figure of merit. However, the average number of false-positives per image resulting from the computerized models remained the same as that obtained from the unaided read modes. Individual computerized models (the machine) that combine image assessments from CAD standalone, unaided read, and CAD-aided read can increase detection performance compared to the reading done by the observer. However, relative sensitivity (ie, the difference in sensitivity between CAD standalone and unaided read) was a critical factor that determined incremental improvement in decision making, whether made by the observer or using computerized models. Published by Elsevier Inc.

Stain susceptibility of composite and ceramic CAD/CAM blocks versus direct resin composites with different resinous matrices.

PubMed

Alharbi, Amal; Ardu, Stefano; Bortolotto, Tissiana; Krejci, Ivo

2017-04-01

To evaluate the stain susceptibility of CAD/CAM blocks and direct composite after long term exposure to various staining agents. 40 disk-shaped samples were fabricated from each of nine materials; six CAD/CAM (Vitablocs Mark II, Paradigm MZ100, Experimental Vita Hybrid Ceramic, Vita Enamic, Experimental Kerr and Lava Ultimate) and three direct composites (Filtek Supreme, Venus Diamond and Filtek Silorane). Samples were randomly divided into five groups (n = 8) according to different staining solutions (distilled water, tea, red wine, coffee and artificial saliva). Initial L*a*b* values were assessed using a calibrated digital spectrophotometer. Specimens were immersed in staining solutions and stored in an incubator at 37 °C for 120 days. L*a*b* values were assessed again and color change (∆E) was calculated as difference between recorded L*a*b* values. ANOVA, and Duncan test were used to identify differences between groups (α = 0.05). Significant differences in ∆E values were detected between materials (p = 0.000). Among all staining solutions, the highest ∆E value was observed with red wine. The new CAD/CAM blocks (Vita Enamic, Vita Hybrid Ceramic and Lava Ultimate) showed the highest resistance to staining compared to the MZ100 composite resin blocks. Filtek Silorane, a direct composite, showed high stain resistance values compared to CAD/CAM materials and other direct composites. Ceramic and composite CAD/CAM blocks had lower staining susceptibility than methacrylate based direct composite. Staining susceptibility of the new resin based CAD/CAM materials Vita Enamic and Lava Ultimate was comparable to feldspathic ceramic blocks (Vitablocs Mark II). Filtek Silorane showed promising results that were comparable to some CAD/CAM blocks.

Integration of a CAS/DGS as a CAD System in the Mathematics Curriculum for Architecture Students

ERIC Educational Resources Information Center

Falcon, R. M.

2011-01-01

Students of Architecture and Building Engineering Degrees work with Computer Aided Design systems daily in order to design and model architectonic constructions. Since this kind of software is based on the creation and transformation of geometrical objects, it seems to be a useful tool in Maths classes in order to capture the attention of the…

Three-Dimensional Digital Evaluation of the Fit of Endocrowns Fabricated from Different CAD/CAM Materials.

PubMed

Zimmermann, Moritz; Valcanaia, Andre; Neiva, Gisele; Mehl, Albert; Fasbinder, Dennis

2018-03-06

A wide variety of CAD/CAM materials are available for single-tooth restorations. CAD/CAM material characteristics are different and may influence CAM fabrication accuracy. There is no study investigating the influence of different CAD/CAM materials on the final fit of the restoration. The aim of this study was to evaluate the fit of endocrowns fabricated from different CAD/CAM materials using a new 3D evaluation method with an intraoral scanning system. The null hypothesis was that there are no significant differences for the fitting accuracy of different CAD/CAM materials. Preparation for an endocrown was performed on a maxillary right first molar on a typodont, and restorations were fabricated with a chairside CAD/CAM system (CEREC Omnicam, MCXL). Three groups using three different CAD/CAM materials were established (each n = 10): zirconia-reinforced lithium silicate ceramic (Celtra Duo; CD), leucite-reinforced silicate ceramic (Empress CAD; EM), resin nanoceramic (Lava Ultimate; LU). A 3D digital measurement technique (OraCheck, Cyfex AG) using an intraoral scanner (CEREC Omnicam) was used to measure the difference in fit between the three materials for a master endocrown preparation. The preparation scan and the endocrown fit scan were matched with special difference analysis software OraCheck. Three areas were selected for fitting accuracy measurements: margin (MA), axial (AX), occlusal (OC). Statistical analysis was performed using 80% percentile, one-way ANOVA, and post-hoc Scheffé test. Significance level was set to p = 0.05. Results varied from best 88.9 ± 7.7 μm for marginal fit of resin nanoceramic restorations (LU_MA) to worst 182.3 ± 24.0 μm for occlusal fit of zirconia-reinforced lithium silicate restorations (CD_OC). Statistically significant differences were found both within and among the test groups. Group CD performed statistically significantly different from group LU for marginal fit (MA) and axial fit (AX) (p < 0.05). For occlusal fit (OC), no statistically significant differences were found within all three test groups (p > 0.05). Deviation pattern for differences was visually analyzed with a color-coded scheme for each restoration. Statistically significant differences were found for different CAD/CAM materials if the CAM procedure was identical. Within the limitations of this study, the choice of CAD/CAM material may influence the fitting accuracy of CAD/CAM-fabricated restorations. © 2018 by the American College of Prosthodontists.

Fifty years of computer analysis in chest imaging: rule-based, machine learning, deep learning.

PubMed

van Ginneken, Bram

2017-03-01

Half a century ago, the term "computer-aided diagnosis" (CAD) was introduced in the scientific literature. Pulmonary imaging, with chest radiography and computed tomography, has always been one of the focus areas in this field. In this study, I describe how machine learning became the dominant technology for tackling CAD in the lungs, generally producing better results than do classical rule-based approaches, and how the field is now rapidly changing: in the last few years, we have seen how even better results can be obtained with deep learning. The key differences among rule-based processing, machine learning, and deep learning are summarized and illustrated for various applications of CAD in the chest.

Comparison of plantar pressure distribution in CAD-CAM and prefabricated foot orthoses in patients with flexible flatfeet.

PubMed

Khodaei, Banafsheh; Saeedi, Hassan; Jalali, Maryam; Farzadi, Maede; Norouzi, Ehsan

2017-12-01

The effect of foot orthoses on plantar pressure distribution has been proven by researchers but there are some controversies about advantages of custom-made foot orthoses to less expensive prefabricated foot orthoses. Nineteen flatfeet adults between 18 and 45 participated in this study. CAD-CAM foot orthoses were made for these patients according to their foot scan. Prefabricated foot orthoses were prepared according to their foot size. Plantar pressure, force and contact area were measured using pedar ® -x in-shoe system wearing shoe alone, wearing CAD-CAM foot orthoses and wearing prefabricated foot orthoses. Repeated measures ANOVA model with post-hoc, Bonferroni comparison were used to test differences. CAD-CAM and prefabricated foot orthoses both decreased pressure and force under 2nd, 3-5 metatarsal and heel regions comparing to shoe alone condition. CAD-CAM foot orthosis increased pressure under lateral toe region in comparison to shoe alone and prefabricated foot orthosis. Both foot orthoses increased pressure and contact area in medial midfoot region comparing to shoe alone condition. Increased forces were seen at hallux and lateral toes by prefabricated foot orthoses in comparison with CAD-CAM foot orthoses and control condition, respectively. According to the results, both foot orthoses could decrease the pressure under heel and metatarsal area. It seems that the special design of CAD-CAM foot orthoses could not make great differences in plantar pressure distribution in this sample. Further research is required to determine whether these results are associated with different scan systems or design software. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of Shipbuilding CAD/CAM/CIM Systems - Phase II (Requirements for Future Systems)

DTIC Science & Technology

1997-02-01

INNOVATION MARINE INDUSTRY STANDARDS WELDING INDUSTRIAL ENGINEERING EDUCATION AND TRAINING THE NATIONAL SHIPBUILDING RESEARCH PROGRAM February 1997 NSRP 0479...an analysis of CAD/CAM/CIM in shipyards, ship-design software firms, and alIied industries in Europe, Japan and the U.S. The purpose of the analysis...possible: Black and Veatch Hitachi Ariake Works Industrial Technology Institute Intergraph Corporation Kockums Computer Systems Mitsubishi Heavy Industries

The budget impact of introducing delayed-release dimethyl fumarate for treatment of relapse-remitting multiple sclerosis in Canada.

PubMed

Dorman, Emily; Kansal, Anuraag R; Sarda, Sujata

2015-01-01

Multiple sclerosis (MS) causes significant disability globally and is especially prevalent in Canada. Delayed-release dimethyl fumarate (DMF; also known as gastro-resistant DMF) is an orally administered disease-modifying treatment (DMT) for patients with relapsing-remitting MS (RRMS) that is currently on the market in the US, Australia, Canada, and Europe. A budget impact model (BIM) was developed to assess the financial consequences of introducing DMF for treatment of RRMS in Canada. A BIM calculated the financial consequences of introducing DMF in Canada over 3 years based on RRMS prevalence, treatment market share, and clinical effects. RRMS prevalence in Canada was derived from published literature and natural relapse rates, and disease state distribution from clinical trial data. It was conservatively assumed that 100% of RRMS patients were treated with a DMT. DMF was assumed to absorb market share proportionally from the following current treatments: interferon beta-1a-IM, interferon beta-1a-SC, interferon beta-1b, and glatiramer acetate. Treatment efficacy, in terms of relapse rate reductions and treatment discontinuation rates, was determined from mixed treatment comparison. Treatment costs (including costs of acquisition, monitoring, and administration) and cost of relapse were considered. Deterministic one-way sensitivity analyses were conducted to assess the most sensitive input parameters. Over 3 years, the introduction of DMF resulted in an average annual increase of CAD417 per treated patient per year, with reductions in costs associated with relapses (CAD192/patient/year) partially offsetting increased drug acquisition costs (CAD602/patient/year). On a population level, the average annual cost increase was CAD24,654,237, a CAD 0.68 increase per population covered by the Canadian healthcare system. The main drivers of budget impact were drop-out rates, proportion of RRMS patients treated, and market share assumptions. The acquisition costs of DMF for treatment of RRMS are predicted to be partially offset by reduced costs of relapses in the Canadian healthcare system.

Fracture and Fatigue Resistance of Cemented versus Fused CAD-on Veneers over Customized Zirconia Implant Abutments.

PubMed

Nossair, Shereen Ahmed; Aboushelib, Moustafa N; Morsi, Tarek Salah

2015-01-05

To evaluate the fracture mechanics of cemented versus fused CAD-on veneers on customized zirconia implant abutments. Forty-five identical customized CAD/CAM zirconia implant abutments (0.5 mm thick) were prepared and seated on short titanium implant abutments (Ti base). A second scan was made to fabricate 45 CAD-on veneers (IPS Empress CAD, A2). Fifteen CAD-on veneers were cemented on the zirconia abutments (Panavia F2.0). Another 15 were fused to the zirconia abutments using low-fusing glass, while manually layered veneers served as control (n = 15). The restorations were subjected to artificial aging (3.2 million cycles between 5 and 10 kg in a water bath at 37°C) before being axially loaded to failure. Fractured specimens were examined using scanning electron microscopy to detect fracture origin, location, and size of critical crack. Stress at failure was calculated using fractography principles (alpha = 0.05). Cemented CAD-on restorations demonstrated significantly higher (F = 72, p < 0.001) fracture load compared to fused CAD-on and manually layered restorations. Fractographic analysis of fractured specimens indicated that cemented CAD-on veneers failed due to radial cracks originating from the veneer/resin interface. Branching of the critical crack was observed in the bulk of the veneer. Fused CAD-on veneers demonstrated cohesive fracture originating at the thickest part of the veneer ceramic, while manually layered veneers failed due to interfacial fracture at the zirconia/veneer interface. Within the limitations of this study, cemented CAD-on veneers on customized zirconia implant abutments demonstrated higher fracture than fused and manually layered veneers. © 2014 by the American College of Prosthodontists.

Detection of breast cancer with full-field digital mammography and computer-aided detection.

PubMed

The, Juliette S; Schilling, Kathy J; Hoffmeister, Jeffrey W; Friedmann, Euvondia; McGinnis, Ryan; Holcomb, Richard G

2009-02-01

The purpose of this study was to evaluate computer-aided detection (CAD) performance with full-field digital mammography (FFDM). CAD (Second Look, version 7.2) was used to evaluate 123 cases of breast cancer detected with FFDM (Senographe DS). Retrospectively, CAD sensitivity was assessed using breast density, mammographic presentation, histopathology results, and lesion size. To determine the case-based false-positive rate, patients with four standard views per case were included in the study group. Eighteen unilateral mammography examinations with nonstandard views were excluded, resulting in a sample of 105 bilateral cases. CAD detected 115 (94%) of 123 cancer cases: six of six (100%) in fatty breasts, 63 of 66 (95%) in breasts containing scattered fibroglandular densities, 43 of 46 (93%) in heterogeneously dense breasts, and three of five (60%) in extremely dense breasts. CAD detected 93% (41/44) of cancers manifesting as calcifications, 92% (57/62) as masses, and 100% (17/17) as mixed masses and calcifications. CAD detected 94% of the invasive ductal carcinomas (n = 63), 100% of the invasive lobular carcinomas (n = 7), 91% of the other invasive carcinomas (n = 11), and 93% of the ductal carcinomas in situ (n = 42). CAD sensitivity for cancers 1-10 mm (n = 55) was 89%; 11-20 mm (n = 37), 97%; 21-30 mm (n = 16), 100%; and larger than 30 mm (n = 15), 93%. The CAD false-positive rate was 2.3 marks per four-image case. CAD with FFDM showed a high sensitivity in identifying cancers manifesting as calcifications and masses. Sensitivity was maintained in cancers with lower mammographic sensitivity, including invasive lobular carcinomas and small neoplasms (1-20 mm). CAD with FFDM should be effective in assisting radiologists with earlier detection of breast cancer. Future studies are needed to assess CAD accuracy in larger populations.

Computer Aided Drafting Curriculum for Vocational Drafting. A Competency Based Unit of Instruction. Final Report.

ERIC Educational Resources Information Center

Peck, Greg

This document contains (1) the final report of a project to develop a computer-aided drafting (CAD) curriculum and (2) a competency-based unit of instruction for use with the CADAPPLE system. The final report states the problem and project objective, presents conclusions and recommendations, and includes survey instruments. The unit is designed…

A SINDA thermal model using CAD/CAE technologies

NASA Technical Reports Server (NTRS)

Rodriguez, Jose A.; Spencer, Steve

1992-01-01

The approach to thermal analysis described by this paper is a technique that incorporates Computer Aided Design (CAD) and Computer Aided Engineering (CAE) to develop a thermal model that has the advantages of Finite Element Methods (FEM) without abandoning the unique advantages of Finite Difference Methods (FDM) in the analysis of thermal systems. The incorporation of existing CAD geometry, the powerful use of a pre and post processor and the ability to do interdisciplinary analysis, will be described.

Effect of Home Bleaching on the Translucency of CAD/CAM Systems.

PubMed

Karci, Muhammet; Demir, Necla

2017-11-10

To evaluate the effect of a home bleaching agent (Opalescence PF) on the translucency of CAD/CAM ceramic systems. The 28 sintered ceramic specimens (IPS Empress CAD and IPS e.max CAD; 15 mm long, 10 mm wide, 1 mm thick) were divided into two subgroups as control and bleaching groups (n = 7). Carbamide peroxide (CP), 16%, home bleaching agent was applied onto the surface of each specimen for 6 hours per day for 7 days. A spectrophotometer (VITA Easyshade Advance) was used to measure the CIE L * a * b * coordinates and the reflectance value (Y) of the specimens on white and black backgrounds. The translucency parameter (TP), contrast ratio (CR), and opalescence parameter (OP) of the specimens were calculated. The data were statistically analyzed using Kolmogorov-Smirnov, one-way ANOVA, Tukey's test, and Pearson's correlation. Statistically significant differences in the TP values after 16% CP bleaching treatment were observed (p ˂ 0.05); however, no significant differences were found in the OP and CR values after the surface treatment (p ˃ 0.05). According to our study, patients who have all-ceramic restorations in their mouths should be careful when using home bleaching agents, because whitening agents can affect the translucency of all-ceramic restorations such as e.max CAD and Empress CAD. © 2017 by the American College of Prosthodontists.

Concerns of Hydrothermal Degradation in CAD/CAM Zirconia

PubMed Central

Kim, J.-W.; Covel, N.S.; Guess, P.C.; Rekow, E.D.; Zhang, Y.

2010-01-01

Zirconia-based restorations are widely used in prosthetic dentistry; however, their susceptibility to hydrothermal degradation remains elusive. We hypothesized that CAD/CAM machining and subsequent surface treatments, i.e., grinding and/or grit-blasting, have marked effects on the hydrothermal degradation behavior of Y-TZP. CAD/CAM-machined Y-TZP plates (0.5 mm thick), both with and without subsequent grinding with various grit sizes or grit-blasting with airborne alumina particles, were subjected to accelerated aging tests in a steam autoclave. Results showed that the CAD/CAM-machined surfaces initially exhibited superior hydrothermal degradation resistance, but deteriorated at a faster rate upon prolonged autoclave treatment compared with ground and grit-blasted surfaces. The accelerated hydrothermal degradation of CAD/CAM surfaces is attributed to the CAD/CAM machining damage and the absence of surface compressive stresses in the fully sintered material. Clinical relevance for surface treatments of zirconia frameworks in terms of hydrothermal and structural stabilities is addressed. PMID:19966039

Cost and resource utilization associated with use of computed tomography to evaluate chest pain in the emergency department: the Rule Out Myocardial Infarction using Computer Assisted Tomography (ROMICAT) study.

PubMed

Hulten, Edward; Goehler, Alexander; Bittencourt, Marcio Sommer; Bamberg, Fabian; Schlett, Christopher L; Truong, Quynh A; Nichols, John; Nasir, Khurram; Rogers, Ian S; Gazelle, Scott G; Nagurney, John T; Hoffmann, Udo; Blankstein, Ron

2013-09-01

Coronary computed tomographic angiography (cCTA) allows rapid, noninvasive exclusion of obstructive coronary artery disease (CAD). However, concern exists whether implementation of cCTA in the assessment of patients presenting to the emergency department with acute chest pain will lead to increased downstream testing and costs compared with alternative strategies. Our aim was to compare observed actual costs of usual care (UC) with projected costs of a strategy including early cCTA in the evaluation of patients with acute chest pain in the Rule Out Myocardial Infarction Using Computer Assisted Tomography I (ROMICAT I) study. We compared cost and hospital length of stay of UC observed among 368 patients enrolled in the ROMICAT I study with projected costs of management based on cCTA. Costs of UC were determined by an electronic cost accounting system. Notably, UC was not influenced by cCTA results because patients and caregivers were blinded to the cCTA results. Costs after early implementation of cCTA were estimated assuming changes in management based on cCTA findings of the presence and severity of CAD. Sensitivity analysis was used to test the influence of key variables on both outcomes and costs. We determined that in comparison with UC, cCTA-guided triage, whereby patients with no CAD are discharged, could reduce total hospital costs by 23% (P<0.001). However, when the prevalence of obstructive CAD increases, index hospitalization cost increases such that when the prevalence of ≥ 50% stenosis is >28% to 33%, the use of cCTA becomes more costly than UC. cCTA may be a cost-saving tool in acute chest pain populations that have a prevalence of potentially obstructive CAD <30%. However, increased cost would be anticipated in populations with higher prevalence of disease.

Relational Information Management Data-Base System

NASA Technical Reports Server (NTRS)

Storaasli, O. O.; Erickson, W. J.; Gray, F. P.; Comfort, D. L.; Wahlstrom, S. O.; Von Limbach, G.

1985-01-01

DBMS with several features particularly useful to scientists and engineers. RIM5 interfaced with any application program written in language capable of Calling FORTRAN routines. Applications include data management for Space Shuttle Columbia tiles, aircraft flight tests, high-pressure piping, atmospheric chemistry, census, university registration, CAD/CAM Geometry, and civil-engineering dam construction.

CAD Integration : new optical design possibilities

NASA Astrophysics Data System (ADS)

Haumonte, Jean-Baptiste; Venturino, Jean-Claude

2005-09-01

The development of optical design and analysis tools in a CAD software can help to optimise the design, size and performance of tomorrow's consumer products. While optics was still held back by software limitations, CAD programs were moving forward in leaps and bounds, improving manufacturing technologies and making it possible to design and produce highly innovative and sophisticated products. The problem was that in the past, 'traditional' optical design programs were only able to simulate spherical and aspherical lenses, meaning that the optical designers were limited to designing systems which were a series of imperfect lenses, each one correcting the last. That is why OPTIS has created the first optical design program to be fully integrated into a CAD program. The technology is available from OPTIS in an integrated SOLIDWORKS or CATIA V5 version. Users of this software can reduce the number of lenses needed in a system. Designers will now have access to complex surfaces such as NURBS meaning they will now be able to define free shape progressive lenses and even improve on optical performances using fewer lenses. This revolutionary technology will allow mechanical designers to work on optical systems and to share information with optical designers for the first time. Previously not possible in a CAD program you may now determine all the optical performances of any optical system, providing first order and third order performances, sequential and non-sequential ray-tracing, wavefront surfaces, point spread function, MTF, spot-diagram, using real optical surfaces and guaranteeing the mechanical precision necessary for an optical system.

Fractography of clinically fractured, implant-supported dental computer-aided design and computer-aided manufacturing crowns

PubMed Central

Lohbauer, Ulrich; Belli, Renan; Cune, Marco S; Schepke, Ulf

2017-01-01

Today, a substantial part of the dental crown production uses computer-aided design and computer-aided manufacturing (CAD/CAM) technology. A recent step in restorative dentistry is the replacement of natural tooth structure with pre-polymerized and machined resin-based methacrylic polymers. Recently, a new CAD/CAM composite was launched for the crown indication in the load-bearing area, but the clinical reality forced the manufacturer to withdraw this specific indication. In parallel, a randomized clinical trial of CAD/CAM composite crowns luted on zirconia implant abutments revealed a high incidence of failure within the first year of service. Fractured crowns of this clinical trial were retrieved and submitted to a fractographic examination. The aim of the case series presented in this article was to identify failure reasons for a new type of CAD/CAM composite crown material (Lava Ultimate; 3M Oral Care, St. Paul, Minnesota, USA) via fractographic examinations and analytical assessment of luting surfaces and water absorption behavior. As a result, the debonding of the composite crowns from the zirconia implant abutments was identified as the central reason for failure. The adhesive interface was found the weakest link. A lack of silica at the zirconia surface certainly has compromised the bonding potential of the adhesive system from the beginning. Additionally, the hydrolytic stress released from swelling of the resin-based crown (water absorption) and transfer to the luting interface further added to the interfacial stress and most probably contributed to a great extend to the debonding failure. PMID:29204275

Fractography of clinically fractured, implant-supported dental computer-aided design and computer-aided manufacturing crowns.

PubMed

Lohbauer, Ulrich; Belli, Renan; Cune, Marco S; Schepke, Ulf

2017-01-01

Today, a substantial part of the dental crown production uses computer-aided design and computer-aided manufacturing (CAD/CAM) technology. A recent step in restorative dentistry is the replacement of natural tooth structure with pre-polymerized and machined resin-based methacrylic polymers. Recently, a new CAD/CAM composite was launched for the crown indication in the load-bearing area, but the clinical reality forced the manufacturer to withdraw this specific indication. In parallel, a randomized clinical trial of CAD/CAM composite crowns luted on zirconia implant abutments revealed a high incidence of failure within the first year of service. Fractured crowns of this clinical trial were retrieved and submitted to a fractographic examination. The aim of the case series presented in this article was to identify failure reasons for a new type of CAD/CAM composite crown material (Lava Ultimate; 3M Oral Care, St. Paul, Minnesota, USA) via fractographic examinations and analytical assessment of luting surfaces and water absorption behavior. As a result, the debonding of the composite crowns from the zirconia implant abutments was identified as the central reason for failure. The adhesive interface was found the weakest link. A lack of silica at the zirconia surface certainly has compromised the bonding potential of the adhesive system from the beginning. Additionally, the hydrolytic stress released from swelling of the resin-based crown (water absorption) and transfer to the luting interface further added to the interfacial stress and most probably contributed to a great extend to the debonding failure.

Increased genetic risk for obesity in premature coronary artery disease.

PubMed

Cole, Christopher B; Nikpay, Majid; Stewart, Alexandre F R; McPherson, Ruth

2016-04-01

There is ongoing controversy as to whether obesity confers risk for CAD independently of associated risk factors including diabetes mellitus. We have carried out a Mendelian randomization study using a genetic risk score (GRS) for body mass index (BMI) based on 35 risk alleles to investigate this question in a population of 5831 early onset CAD cases without diabetes mellitus and 3832 elderly healthy control subjects, all of strictly European ancestry, with adjustment for traditional risk factors (TRFs). We then estimated the genetic correlation between these BMI and CAD (rg) by relating the pairwise genetic similarity matrix to a phenotypic covariance matrix between these two traits. GRSBMI significantly (P=2.12 × 10(-12)) associated with CAD status in a multivariate model adjusted for TRFs, with a per allele odds ratio (OR) of 1.06 (95% CI 1.042-1.076). The addition of GRSBMI to TRFs explained 0.75% of CAD variance and yielded a continuous net recombination index of 16.54% (95% CI=11.82-21.26%, P<0.0001). To test whether GRSBMI explained CAD status when adjusted for measured BMI, separate models were constructed in which the score and BMI were either included as covariates or not. The addition of BMI explained ~1.9% of CAD variance and GRSBMI plus BMI explained 2.65% of CAD variance. Finally, using bivariate restricted maximum likelihood analysis, we provide strong evidence of genome-wide pleiotropy between obesity and CAD. This analysis supports the hypothesis that obesity is a causal risk factor for CAD.

Interval training based on ventilatory anaerobic threshold increases cardiac vagal modulation and decreases high-sensitivity c-reative protein: randomized clinical trial in coronary artery disease.

PubMed

Tamburus, Nayara Y; Paula, Roberta F L; Kunz, Vandeni C; César, Marcelo C; Moreno, Marlene A; da Silva, Ester

2015-01-01

Autonomic dysfunction and inflammatory activity are involved in the development and progression of coronary artery disease (CAD), and exercise training has been shown to confer a cardiovascular benefit. To evaluate the effects that interval training (IT) based on ventilatory anaerobic threshold (VAT) has on heart rate variability (HRV) and high-sensitivity C-reactive protein (hs-CRP) levels, as well as the relationship between both levels, in patients with CAD and/or cardiovascular risk factors (RF). Forty-two men (aged 57.88±6.20 years) were divided into two training groups, CAD-T (n= 12) and RF-T (n= 10), and two control groups, CAD-C (n= 10) and RF-C (n=10). Heart rate and RR intervals in the supine position, cardiopulmonary exercise tests, and hs-CRP levels were measured before and after IT. HRV was analyzed by spectral and symbolic analysis. The CAD-T and RF-T underwent a 16-week IT program of three weekly sessions at training intensities based on the VAT. In the RF-T, cardiac sympathetic modulation index and hs-CRP decreased (p<0.02), while cardiac parasympathetic modulation index increased (p<0.02). In the CAD-T, cardiac parasympathetic modulation index increased, while hs-CRP, systolic, and diastolic blood pressures decreased (p<0.02). Both control groups showed increase in hs-CRP parameters (p<0.02). There was a strong and significant association between parasympathetic and sympathetic modulations with hs-CRP. The IT program based on the VAT promoted a decrease in hs-CRP associated with improvement in cardiac autonomic modulation.

ClusterCAD: a computational platform for type I modular polyketide synthase design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eng, Clara H.; Backman, Tyler W H; Bailey, Constance B.

Here, we present ClusterCAD, a web-based toolkit designed to leverage the collinear structure and deterministic logic of type I modular polyketide synthases (PKSs) for synthetic biology applications. The unique organization of these megasynthases, combined with the diversity of their catalytic domain building blocks, has fueled an interest in harnessing the biosynthetic potential of PKSs for the microbial production of both novel natural product analogs and industrially relevant small molecules. However, a limited theoretical understanding of the determinants of PKS fold and function poses a substantial barrier to the design of active variants, and identifying strategies to reliably construct functional PKSmore » chimeras remains an active area of research. In this work, we formalize a paradigm for the design of PKS chimeras and introduce ClusterCAD as a computational platform to streamline and simplify the process of designing experiments to test strategies for engineering PKS variants. ClusterCAD provides chemical structures with stereochemistry for the intermediates generated by each PKS module, as well as sequence- and structure-based search tools that allow users to identify modules based either on amino acid sequence or on the chemical structure of the cognate polyketide intermediate. ClusterCAD can be accessed at https://clustercad.jbei.org and at http://clustercad.igb.uci.edu.« less

ClusterCAD: a computational platform for type I modular polyketide synthase design

DOE PAGES

Eng, Clara H.; Backman, Tyler W H; Bailey, Constance B.; ...

2017-10-11

Here, we present ClusterCAD, a web-based toolkit designed to leverage the collinear structure and deterministic logic of type I modular polyketide synthases (PKSs) for synthetic biology applications. The unique organization of these megasynthases, combined with the diversity of their catalytic domain building blocks, has fueled an interest in harnessing the biosynthetic potential of PKSs for the microbial production of both novel natural product analogs and industrially relevant small molecules. However, a limited theoretical understanding of the determinants of PKS fold and function poses a substantial barrier to the design of active variants, and identifying strategies to reliably construct functional PKSmore » chimeras remains an active area of research. In this work, we formalize a paradigm for the design of PKS chimeras and introduce ClusterCAD as a computational platform to streamline and simplify the process of designing experiments to test strategies for engineering PKS variants. ClusterCAD provides chemical structures with stereochemistry for the intermediates generated by each PKS module, as well as sequence- and structure-based search tools that allow users to identify modules based either on amino acid sequence or on the chemical structure of the cognate polyketide intermediate. ClusterCAD can be accessed at https://clustercad.jbei.org and at http://clustercad.igb.uci.edu.« less

Single High Fidelity Geometric Data Sets for LCM - Model Requirements

DTIC Science & Technology

2006-11-01

are extensive single 3D CAD data models incorporating hull structure, propulsion, steering, piping , electrical, HVAC and other systems, which make...single 3D CAD data models incorporating hull structure, propulsion, steering, piping , electrical, HVAC and other systems. During this same period...be sufficiently flexible to accommodate the diverse requirements of various types of structural analyses. Section Properties & Material Data

Automated melanoma recognition in dermoscopic images based on extreme learning machine (ELM)

NASA Astrophysics Data System (ADS)

Rahman, Md. Mahmudur; Alpaslan, Nuh

2017-03-01

Melanoma is considered a major health problem since it is the deadliest form of skin cancer. The early diagnosis through periodic screening with dermoscopic images can significantly improve the survival rate as well as reduce the treatment cost and consequent suffering of patients. Dermoscopy or skin surface microscopy provides in vivo inspection of color and morphologic structures of pigmented skin lesions (PSLs), rendering higher accuracy for detecting suspicious cases than it is possible via inspecting with naked eye. However, interpretation of dermoscopic images is time consuming and subjective, even for trained dermatologists. Therefore, there is currently a great interest in the development of computeraided diagnosis (CAD) systems for automated melanoma recognition. However, the majority of the CAD systems are still in the early development stage with lack of descriptive feature generation and benchmark evaluation in ground-truth datasets. This work is focusing on by addressing the various issues related to the development of such a CAD system with effective feature extraction from Non-Subsampled Contourlet Transform (NSCT) and Eig(Hess) histogram of oriented gradients (HOG) and lesion classification with efficient Extreme Learning Machine (ELM) due to its good generalization abilities and a high learning efficiency and evaluating its effectiveness in a benchmark data set of dermoscopic images towards the goal of realistic comparison and real clinical integration. The proposed research on melanoma recognition has huge potential for offering powerful services that would significantly benefit the present Biomedical Information Systems.

Fabricating CAD/CAM Implant-Retained Mandibular Bar Overdentures: A Clinical and Technical Overview.

PubMed

Goo, Chui Ling; Tan, Keson Beng Choon

2017-01-01

This report describes the clinical and technical aspects in the oral rehabilitation of an edentulous patient with knife-edge ridge at the mandibular anterior edentulous region, using implant-retained overdentures. The application of computer-aided design and computer-aided manufacturing (CAD/CAM) in the fabrication of the overdenture framework simplifies the laboratory process of the implant prostheses. The Nobel Procera CAD/CAM System was utilised to produce a lightweight titanium overdenture bar with locator attachments. It is proposed that the digital workflow of CAD/CAM milled implant overdenture bar allows us to avoid numerous technical steps and possibility of casting errors involved in the conventional casting of such bars.

A Human Activity Recognition System Based on Dynamic Clustering of Skeleton Data.

PubMed

Manzi, Alessandro; Dario, Paolo; Cavallo, Filippo

2017-05-11

Human activity recognition is an important area in computer vision, with its wide range of applications including ambient assisted living. In this paper, an activity recognition system based on skeleton data extracted from a depth camera is presented. The system makes use of machine learning techniques to classify the actions that are described with a set of a few basic postures. The training phase creates several models related to the number of clustered postures by means of a multiclass Support Vector Machine (SVM), trained with Sequential Minimal Optimization (SMO). The classification phase adopts the X-means algorithm to find the optimal number of clusters dynamically. The contribution of the paper is twofold. The first aim is to perform activity recognition employing features based on a small number of informative postures, extracted independently from each activity instance; secondly, it aims to assess the minimum number of frames needed for an adequate classification. The system is evaluated on two publicly available datasets, the Cornell Activity Dataset (CAD-60) and the Telecommunication Systems Team (TST) Fall detection dataset. The number of clusters needed to model each instance ranges from two to four elements. The proposed approach reaches excellent performances using only about 4 s of input data (~100 frames) and outperforms the state of the art when it uses approximately 500 frames on the CAD-60 dataset. The results are promising for the test in real context.

Assistive lesion-emphasis system: an assistive system for fundus image readers

PubMed Central

Rangrej, Samrudhdhi B.; Sivaswamy, Jayanthi

2017-01-01

Abstract. Computer-assisted diagnostic (CAD) tools are of interest as they enable efficient decision-making in clinics and the screening of diseases. The traditional approach to CAD algorithm design focuses on the automated detection of abnormalities independent of the end-user, who can be an image reader or an expert. We propose a reader-centric system design wherein a reader’s attention is drawn to abnormal regions in a least-obtrusive yet effective manner, using saliency-based emphasis of abnormalities and without altering the appearance of the background tissues. We present an assistive lesion-emphasis system (ALES) based on the above idea, for fundus image-based diabetic retinopathy diagnosis. Lesion-saliency is learnt using a convolutional neural network (CNN), inspired by the saliency model of Itti and Koch. The CNN is used to fine-tune standard low-level filters and learn high-level filters for deriving a lesion-saliency map, which is then used to perform lesion-emphasis via a spatially variant version of gamma correction. The proposed system has been evaluated on public datasets and benchmarked against other saliency models. It was found to outperform other saliency models by 6% to 30% and boost the contrast-to-noise ratio of lesions by more than 30%. Results of a perceptual study also underscore the effectiveness and, hence, the potential of ALES as an assistive tool for readers. PMID:28560245

rCAD: A Novel Database Schema for the Comparative Analysis of RNA.

PubMed

Ozer, Stuart; Doshi, Kishore J; Xu, Weijia; Gutell, Robin R

2011-12-31

Beyond its direct involvement in protein synthesis with mRNA, tRNA, and rRNA, RNA is now being appreciated for its significance in the overall metabolism and regulation of the cell. Comparative analysis has been very effective in the identification and characterization of RNA molecules, including the accurate prediction of their secondary structure. We are developing an integrative scalable data management and analysis system, the RNA Comparative Analysis Database (rCAD), implemented with SQL Server to support RNA comparative analysis. The platformagnostic database schema of rCAD captures the essential relationships between the different dimensions of information for RNA comparative analysis datasets. The rCAD implementation enables a variety of comparative analysis manipulations with multiple integrated data dimensions for advanced RNA comparative analysis workflows. In this paper, we describe details of the rCAD schema design and illustrate its usefulness with two usage scenarios.

rCAD: A Novel Database Schema for the Comparative Analysis of RNA

PubMed Central

Ozer, Stuart; Doshi, Kishore J.; Xu, Weijia; Gutell, Robin R.

2013-01-01

Beyond its direct involvement in protein synthesis with mRNA, tRNA, and rRNA, RNA is now being appreciated for its significance in the overall metabolism and regulation of the cell. Comparative analysis has been very effective in the identification and characterization of RNA molecules, including the accurate prediction of their secondary structure. We are developing an integrative scalable data management and analysis system, the RNA Comparative Analysis Database (rCAD), implemented with SQL Server to support RNA comparative analysis. The platformagnostic database schema of rCAD captures the essential relationships between the different dimensions of information for RNA comparative analysis datasets. The rCAD implementation enables a variety of comparative analysis manipulations with multiple integrated data dimensions for advanced RNA comparative analysis workflows. In this paper, we describe details of the rCAD schema design and illustrate its usefulness with two usage scenarios. PMID:24772454

Understanding dental CAD/CAM for restorations--the digital workflow from a mechanical engineering viewpoint.

PubMed

Tapie, L; Lebon, N; Mawussi, B; Fron Chabouis, H; Duret, F; Attal, J-P

2015-01-01

As digital technology infiltrates every area of daily life, including the field of medicine, so it is increasingly being introduced into dental practice. Apart from chairside practice, computer-aided design/computer-aided manufacturing (CAD/CAM) solutions are available for creating inlays, crowns, fixed partial dentures (FPDs), implant abutments, and other dental prostheses. CAD/CAM dental solutions can be considered a chain of digital devices and software for the almost automatic design and creation of dental restorations. However, dentists who want to use the technology often do not have the time or knowledge to understand it. A basic knowledge of the CAD/CAM digital workflow for dental restorations can help dentists to grasp the technology and purchase a CAM/CAM system that meets the needs of their office. This article provides a computer-science and mechanical-engineering approach to the CAD/CAM digital workflow to help dentists understand the technology.

Safety Profile and Costs of Related Adverse Events of Trastuzumab Emtansine for the Treatment of HER2-Positive Locally Advanced or Metastatic Breast Cancer Compared to Capecitabine Plus Lapatinib from the Perspective of the Canadian Health-Care System.

PubMed

Piwko, Charles; Prady, Catherine; Yunger, Simon; Pollex, Erika; Moser, Aurelie

2015-08-01

Trastuzumab emtansine (T-DM1, KADCYLA(®)) is an antibody-drug conjugate comprised of the cytotoxic agent DM1 and trastuzumab (HERCEPTIN(®)). The safety profile of T-DM1 in human epidermal growth factor receptor 2 (HER2)-positive locally advanced or metastatic breast cancer previously treated with trastuzumab and a taxane was investigated in the phase III EMILIA trial. The trial demonstrated clinically and statistically meaningful differences in the safety profile between T-DM1 and capecitabine plus lapatinib (CAP + LAP). The objective of this study was to estimate the costs of managing treatment-related grade ≥ 3 adverse events (AEs) that occurred in ≥ 2% of patients and grade 2 AEs that occurred in ≥ 5% of patients taking T-DM1 compared with patients taking CAP + LAP based on the EMILIA trial, from the perspective of Canadian public payers. An Excel-based model was utilized to estimate the relevant costs. Clinical data were obtained from the EMILIA trial. Cost information was obtained from the literature, clinical experts, and standard cost sources. The analysis was conducted from the Canadian public-payer perspective and reported in 2014 Canadian dollars (CAD). The management of included treatment-related AEs resulted in higher estimated per-patient costs of CAD6901 for CAP + LAP versus CAD3380 for T-DM1, resulting in savings of CAD3521. From a Canadian perspective, this analysis demonstrated that utilizing T-DM1 for the management of HER2-positive metastatic breast cancer results in substantial savings to the public health-care system when considering the costs of treatment-related AEs, due to fewer amount of toxicities compared with CAP + LAP. Results of various sensitivity analyses investigating changes in number and costs of AEs confirmed the findings; however, the magnitude of cost savings varied. Further analyses are necessary to determine whether these cost savings would occur in other countries and health-care systems.

Computer-aided detection of brain metastasis on 3D MR imaging: Observer performance study.

PubMed

Sunwoo, Leonard; Kim, Young Jae; Choi, Seung Hong; Kim, Kwang-Gi; Kang, Ji Hee; Kang, Yeonah; Bae, Yun Jung; Yoo, Roh-Eul; Kim, Jihang; Lee, Kyong Joon; Lee, Seung Hyun; Choi, Byung Se; Jung, Cheolkyu; Sohn, Chul-Ho; Kim, Jae Hyoung

2017-01-01

To assess the effect of computer-aided detection (CAD) of brain metastasis (BM) on radiologists' diagnostic performance in interpreting three-dimensional brain magnetic resonance (MR) imaging using follow-up imaging and consensus as the reference standard. The institutional review board approved this retrospective study. The study cohort consisted of 110 consecutive patients with BM and 30 patients without BM. The training data set included MR images of 80 patients with 450 BM nodules. The test set included MR images of 30 patients with 134 BM nodules and 30 patients without BM. We developed a CAD system for BM detection using template-matching and K-means clustering algorithms for candidate detection and an artificial neural network for false-positive reduction. Four reviewers (two neuroradiologists and two radiology residents) interpreted the test set images before and after the use of CAD in a sequential manner. The sensitivity, false positive (FP) per case, and reading time were analyzed. A jackknife free-response receiver operating characteristic (JAFROC) method was used to determine the improvement in the diagnostic accuracy. The sensitivity of CAD was 87.3% with an FP per case of 302.4. CAD significantly improved the diagnostic performance of the four reviewers with a figure-of-merit (FOM) of 0.874 (without CAD) vs. 0.898 (with CAD) according to JAFROC analysis (p < 0.01). Statistically significant improvement was noted only for less-experienced reviewers (FOM without vs. with CAD, 0.834 vs. 0.877, p < 0.01). The additional time required to review the CAD results was approximately 72 sec (40% of the total review time). CAD as a second reader helps radiologists improve their diagnostic performance in the detection of BM on MR imaging, particularly for less-experienced reviewers.

The effect of varying levels of vehicle automation on drivers' lane changing behaviour.

PubMed

Madigan, Ruth; Louw, Tyron; Merat, Natasha

2018-01-01

Much of the Human Factors research into vehicle automation has focused on driver responses to critical scenarios where a crash might occur. However, there is less knowledge about the effects of vehicle automation on drivers' behaviour during non-critical take-over situations, such as driver-initiated lane-changing or overtaking. The current driving simulator study, conducted as part of the EC-funded AdaptIVe project, addresses this issue. It uses a within-subjects design to compare drivers' lane-changing behaviour in conventional manual driving, partially automated driving (PAD) and conditionally automated driving (CAD). In PAD, drivers were required to re-take control from an automated driving system in order to overtake a slow moving vehicle, while in CAD, the driver used the indicator lever to initiate a system-performed overtaking manoeuvre. Results showed that while drivers' acceptance of both the PAD and CAD systems was high, they generally preferred CAD. A comparison of overtaking positions showed that drivers initiated overtaking manoeuvres slightly later in PAD than in manual driving or CAD. In addition, when compared to conventional driving, drivers had higher deviations in lane positioning and speed, along with higher lateral accelerations during lane changes following PAD. These results indicate that even in situations which are not time-critical, drivers' vehicle control after automation is degraded compared to conventional driving.

The effect of varying levels of vehicle automation on drivers’ lane changing behaviour

PubMed Central

Louw, Tyron; Merat, Natasha

2018-01-01

Much of the Human Factors research into vehicle automation has focused on driver responses to critical scenarios where a crash might occur. However, there is less knowledge about the effects of vehicle automation on drivers’ behaviour during non-critical take-over situations, such as driver-initiated lane-changing or overtaking. The current driving simulator study, conducted as part of the EC-funded AdaptIVe project, addresses this issue. It uses a within-subjects design to compare drivers’ lane-changing behaviour in conventional manual driving, partially automated driving (PAD) and conditionally automated driving (CAD). In PAD, drivers were required to re-take control from an automated driving system in order to overtake a slow moving vehicle, while in CAD, the driver used the indicator lever to initiate a system-performed overtaking manoeuvre. Results showed that while drivers’ acceptance of both the PAD and CAD systems was high, they generally preferred CAD. A comparison of overtaking positions showed that drivers initiated overtaking manoeuvres slightly later in PAD than in manual driving or CAD. In addition, when compared to conventional driving, drivers had higher deviations in lane positioning and speed, along with higher lateral accelerations during lane changes following PAD. These results indicate that even in situations which are not time-critical, drivers’ vehicle control after automation is degraded compared to conventional driving. PMID:29466402

Automated CAD design for sculptured airfoil surfaces

NASA Astrophysics Data System (ADS)

Murphy, S. D.; Yeagley, S. R.

1990-11-01

The design of tightly tolerated sculptured surfaces such as those for airfoils requires a significant design effort in order to machine the tools to create these surfaces. Because of the quantity of numerical data required to describe the airfoil surfaces, a CAD approach is required. Although this approach will result in productivity gains, much larger gains can be achieved by automating the design process. This paper discusses an application which resulted in an eightfold improvement in productivity by automating the design process on the CAD system.

The Last Step of Syringyl Monolignol Biosynthesis in Angiosperms Is Regulated by a Novel Gene Encoding Sinapyl Alcohol Dehydrogenase

PubMed Central

Li, Laigeng; Cheng, Xiao Fei; Leshkevich, Jacqueline; Umezawa, Toshiaki; Harding, Scott A.; Chiang, Vincent L.

2001-01-01

Cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) has been thought to mediate the reduction of both coniferaldehyde and sinapaldehyde into guaiacyl and syringyl monolignols in angiosperms. Here, we report the isolation of a novel aspen gene (PtSAD) encoding sinapyl alcohol dehydrogenase (SAD), which is phylogenetically distinct from aspen CAD (PtCAD). Liquid chromatography–mass spectrometry-based enzyme functional analysis and substrate level–controlled enzyme kinetics consistently demonstrated that PtSAD is sinapaldehyde specific and that PtCAD is coniferaldehyde specific. The enzymatic efficiency of PtSAD for sinapaldehyde was ∼60 times greater than that of PtCAD. These data suggest that in addition to CAD, discrete SAD function is essential to the biosynthesis of syringyl monolignol in angiosperms. In aspen stem primary tissues, PtCAD was immunolocalized exclusively to xylem elements in which only guaiacyl lignin was deposited, whereas PtSAD was abundant in syringyl lignin–enriched phloem fiber cells. In the developing secondary stem xylem, PtCAD was most conspicuous in guaiacyl lignin–enriched vessels, but PtSAD was nearly absent from these elements and was conspicuous in fiber cells. In the context of additional protein immunolocalization and lignin histochemistry, these results suggest that the distinct CAD and SAD functions are linked spatiotemporally to the differential biosynthesis of guaiacyl and syringyl lignins in different cell types. SAD is required for the biosynthesis of syringyl lignin in angiosperms. PMID:11449052

The last step of syringyl monolignol biosynthesis in angiosperms is regulated by a novel gene encoding sinapyl alcohol dehydrogenase.

PubMed

Li, L; Cheng, X F; Leshkevich, J; Umezawa, T; Harding, S A; Chiang, V L

2001-07-01

Cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) has been thought to mediate the reduction of both coniferaldehyde and sinapaldehyde into guaiacyl and syringyl monolignols in angiosperms. Here, we report the isolation of a novel aspen gene (PtSAD) encoding sinapyl alcohol dehydrogenase (SAD), which is phylogenetically distinct from aspen CAD (PtCAD). Liquid chromatography-mass spectrometry-based enzyme functional analysis and substrate level-controlled enzyme kinetics consistently demonstrated that PtSAD is sinapaldehyde specific and that PtCAD is coniferaldehyde specific. The enzymatic efficiency of PtSAD for sinapaldehyde was approximately 60 times greater than that of PtCAD. These data suggest that in addition to CAD, discrete SAD function is essential to the biosynthesis of syringyl monolignol in angiosperms. In aspen stem primary tissues, PtCAD was immunolocalized exclusively to xylem elements in which only guaiacyl lignin was deposited, whereas PtSAD was abundant in syringyl lignin-enriched phloem fiber cells. In the developing secondary stem xylem, PtCAD was most conspicuous in guaiacyl lignin-enriched vessels, but PtSAD was nearly absent from these elements and was conspicuous in fiber cells. In the context of additional protein immunolocalization and lignin histochemistry, these results suggest that the distinct CAD and SAD functions are linked spatiotemporally to the differential biosynthesis of guaiacyl and syringyl lignins in different cell types. SAD is required for the biosynthesis of syringyl lignin in angiosperms.

Diagnostic yield and accuracy of coronary CT angiography after abnormal nuclear myocardial perfusion imaging.

PubMed

Meinel, Felix G; Schoepf, U Joseph; Townsend, Jacob C; Flowers, Brian A; Geyer, Lucas L; Ebersberger, Ullrich; Krazinski, Aleksander W; Kunz, Wolfgang G; Thierfelder, Kolja M; Baker, Deborah W; Khan, Ashan M; Fernandes, Valerian L; O'Brien, Terrence X

2018-06-15

We aimed to determine the diagnostic yield and accuracy of coronary CT angiography (CCTA) in patients referred for invasive coronary angiography (ICA) based on clinical concern for coronary artery disease (CAD) and an abnormal nuclear stress myocardial perfusion imaging (MPI) study. We enrolled 100 patients (84 male, mean age 59.6 ± 8.9 years) with an abnormal MPI study and subsequent referral for ICA. Each patient underwent CCTA prior to ICA. We analyzed the prevalence of potentially obstructive CAD (≥50% stenosis) on CCTA and calculated the diagnostic accuracy of ≥50% stenosis on CCTA for the detection of clinically significant CAD on ICA (defined as any ≥70% stenosis or ≥50% left main stenosis). On CCTA, 54 patients had at least one ≥50% stenosis. With ICA, 45 patients demonstrated clinically significant CAD. A positive CCTA had 100% sensitivity and 84% specificity with a 100% negative predictive value and 83% positive predictive value for clinically significant CAD on a per patient basis in MPI positive symptomatic patients. In conclusion, almost half (48%) of patients with suspected CAD and an abnormal MPI study demonstrate no obstructive CAD on CCTA.

Effects of various polishing techniques and thermal cycling on the surface roughness and color change of polymer-based CAD/CAM materials.

PubMed

Acar, Burcu; Egilmez, Ferhan

2018-04-01

To investigate and compare the effects of several polishing systems and thermal cycling on the surface roughness and color change of various polymer-based CAD/CAM materials. Bar-shaped specimens (GC CeraSmart, CS; Lava Ultimate, LU and Vita Enamic, VE) were prepared. All specimens were polished with SiC papers. The specimens in Group A served as control and no additional surface polishing was applied. Final polishing was performed using diamond polishing paste (Diapolisher Paste) in Group B. In Group C, aluminum oxide abrasive discs (Sof-Lex XT Pop on) were used. Group D was polished with diamond impregnated spiral polishing system (EVE Diacomp Plus Twist). In Group E, polishing was done with rubber-based silicon abrasives (Polydentia). Thereafter, the specimens were submitted to thermal cycling. The surface roughness and color measurements were performed. Kruskal-Wallis and the Mann-Whitney U tests were applied for the evaluation of ΔE₀₀ data. Ra data were evaluated using three-way ANOVA. Pearson's correlation between Ra and ΔE₀₀ was further investigated. Neither the CAD/CAM materials nor thermal cycling affected the Ra data (P> 0.05). In contrast, significant difference was found among the polishing methods (P< 0.001). On the other hand, VE showed the highest color change whereas LU showed the lowest (P< 0.05). Additionally, the specimens in Group D exhibited significantly higher color change than other tested groups (P< 0.05). A moderate positive correlation was seen between Ra and ΔE₀₀ data of LU (rho = 0.390, P= 0.01). The diamond impregnated two-stage polishing procedure may not be an appropriate method for the tested CAD/CAM materials, as it resulted in the highest color change. On the other hand, all tested materials exhibited visually perceptible, but clinically acceptable color changes following the different polishing techniques. Additionally, diamond paste polishing could be a clinically acceptable procedure in terms of surface roughness. Copyright©American Journal of Dentistry.

Introduction and Highlights of the Workshop

NASA Technical Reports Server (NTRS)

Noor, Ahmed K.; Venneri, Samuel L.

1997-01-01

Four generations of CAD/CAM systems can be identified, corresponding to changes in both modeling functionality and software architecture. The systems evolved from 2D and wireframes to solid modeling, to parametric/variational modelers to the current simulation-embedded systems. Recent developments have enabled design engineers to perform many of the complex analysis tasks, typically performed by analysis experts. Some of the characteristics of the current and emerging CAD/CAM/CAE systems are described in subsequent presentations. The focus of the workshop is on the potential of CAD/CAM/CAE systems for use in simulating the entire mission and life-cycle of future aerospace systems, and the needed development to realize this potential. First, the major features of the emerging computing, communication and networking environment are outlined; second, the characteristics and design drivers of future aerospace systems are identified; third, the concept of intelligent synthesis environment being planned by NASA, the UVA ACT Center and JPL is presented; and fourth, the objectives and format of the workshop are outlined.

Chairside CAD/CAM materials. Part 3: Cyclic fatigue parameters and lifetime predictions.

PubMed

Wendler, Michael; Belli, Renan; Valladares, Diana; Petschelt, Anselm; Lohbauer, Ulrich

2018-06-01

Chemical and mechanical degradation play a key role on the lifetime of dental restorative materials. Therefore, prediction of their long-term performance in the oral environment should base on fatigue, rather than inert strength data, as commonly observed in the dental material's field. The objective of the present study was to provide mechanistic fatigue parameters of current dental CAD/CAM materials under cyclic biaxial flexure and assess their suitability in predicting clinical fracture behaviors. Eight CAD/CAM materials, including polycrystalline zirconia (IPS e.max ZirCAD), reinforced glasses (Vitablocs Mark II, IPS Empress CAD), glass-ceramics (IPS e.max CAD, Suprinity PC, Celtra Duo), as well as hybrid materials (Enamic, Lava Ultimate) were evaluated. Rectangular plates (12×12×1.2mm 3 ) with highly polished surfaces were prepared and tested in biaxial cyclic fatigue in water until fracture using the Ball-on-Three-Balls (B3B) test. Cyclic fatigue parameters n and A* were obtained from the lifetime data for each material and further used to build SPT diagrams. The latter were used to compare in-vitro with in-vivo fracture distributions for IPS e.max CAD and IPS Empress CAD. Susceptibility to subcritical crack growth under cyclic loading was observed for all materials, being more severe (n≤20) in lithium-based glass-ceramics and Vitablocs Mark II. Strength degradations of 40% up to 60% were predicted after only 1 year of service. Threshold stress intensity factors (K th ) representing the onset of subcritical crack growth (SCG), were estimated to lie in the range of 0.37-0.44 of K Ic for the lithium-based glass-ceramics and Vitablocs Mark II and between 0.51-0.59 of K Ic for the other materials. Failure distributions associated with mechanistic estimations of strength degradation in-vitro showed to be useful in interpreting failure behavior in-vivo. The parameter K th stood out as a better predictor of clinical performance in detriment to the SCG n parameter. Fatigue parameters obtained from cyclic loading experiments are more reliable predictors of the mechanical performance of contemporary dental CAD/CAM restoratives than quasi-static mechanical properties. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Increasing CAD system efficacy for lung texture analysis using a convolutional network

NASA Astrophysics Data System (ADS)

Tarando, Sebastian Roberto; Fetita, Catalin; Faccinetto, Alex; Brillet, Pierre-Yves

2016-03-01

The infiltrative lung diseases are a class of irreversible, non-neoplastic lung pathologies requiring regular follow-up with CT imaging. Quantifying the evolution of the patient status imposes the development of automated classification tools for lung texture. For the large majority of CAD systems, such classification relies on a two-dimensional analysis of axial CT images. In a previously developed CAD system, we proposed a fully-3D approach exploiting a multi-scale morphological analysis which showed good performance in detecting diseased areas, but with a major drawback consisting of sometimes overestimating the pathological areas and mixing different type of lung patterns. This paper proposes a combination of the existing CAD system with the classification outcome provided by a convolutional network, specifically tuned-up, in order to increase the specificity of the classification and the confidence to diagnosis. The advantage of using a deep learning approach is a better regularization of the classification output (because of a deeper insight into a given pathological class over a large series of samples) where the previous system is extra-sensitive due to the multi-scale response on patient-specific, localized patterns. In a preliminary evaluation, the combined approach was tested on a 10 patient database of various lung pathologies, showing a sharp increase of true detections.

Differential Protection of Cry1Fa Toxin against Spodoptera frugiperda Larval Gut Proteases by Cadherin Orthologs Correlates with Increased Synergism

PubMed Central

Rahman, Khalidur; Abdullah, Mohd Amir F.; Ambati, Suresh; Taylor, Milton D.

2012-01-01

The Cry proteins produced by Bacillus thuringiensis (Bt) are the most widely used biopesticides effective against a range of crop pests and disease vectors. Like chemical pesticides, development of resistance is the primary threat to the long-term efficacy of Bt toxins. Recently discovered cadherin-based Bt Cry synergists showed the potential to augment resistance management by improving efficacy of Cry toxins. However, the mode of action of Bt Cry synergists is thus far unclear. Here we elucidate the mechanism of cadherin-based Cry toxin synergism utilizing two cadherin peptides, Spodoptera frugiperda Cad (SfCad) and Manduca sexta Cad (MsCad), which differentially enhance Cry1Fa toxicity to Spodoptera frugiperda neonates. We show that differential SfCad- and MsCad-mediated protection of Cry1Fa toxin in the Spodoptera frugiperda midgut correlates with differential Cry1Fa toxicity enhancement. Both peptides exhibited high affinity for Cry1Fa toxin and an increased rate of Cry1Fa-induced pore formation in S. frugiperda. However, only SfCad bound the S. frugiperda brush border membrane vesicle and more effectively prolonged the stability of Cry1Fa toxin in the gut, explaining higher Cry1Fa enhancement by this peptide. This study shows that cadherin fragments may enhance B. thuringiensis toxicity by at least two different mechanisms or a combination thereof: (i) protection of Cry toxin from protease degradation in the insect midgut and (ii) enhancement of pore-forming ability of Cry toxin. PMID:22081566

The computerized adaptive diagnostic test for major depressive disorder (CAD-MDD): a screening tool for depression.

PubMed

Gibbons, Robert D; Hooker, Giles; Finkelman, Matthew D; Weiss, David J; Pilkonis, Paul A; Frank, Ellen; Moore, Tara; Kupfer, David J

2013-07-01

To develop a computerized adaptive diagnostic screening tool for depression that decreases patient and clinician burden and increases sensitivity and specificity for clinician-based DSM-IV diagnosis of major depressive disorder (MDD). 656 individuals with and without minor and major depression were recruited from a psychiatric clinic and a community mental health center and through public announcements (controls without depression). The focus of the study was the development of the Computerized Adaptive Diagnostic Test for Major Depressive Disorder (CAD-MDD) diagnostic screening tool based on a decision-theoretical approach (random forests and decision trees). The item bank consisted of 88 depression scale items drawn from 73 depression measures. Sensitivity and specificity for predicting clinician-based Structured Clinical Interview for DSM-IV Axis I Disorders diagnoses of MDD were the primary outcomes. Diagnostic screening accuracy was then compared to that of the Patient Health Questionnaire-9 (PHQ-9). An average of 4 items per participant was required (maximum of 6 items). Overall sensitivity and specificity were 0.95 and 0.87, respectively. For the PHQ-9, sensitivity was 0.70 and specificity was 0.91. High sensitivity and reasonable specificity for a clinician-based DSM-IV diagnosis of depression can be obtained using an average of 4 adaptively administered self-report items in less than 1 minute. Relative to the currently used PHQ-9, the CAD-MDD dramatically increased sensitivity while maintaining similar specificity. As such, the CAD-MDD will identify more true positives (lower false-negative rate) than the PHQ-9 using half the number of items. Inexpensive (relative to clinical assessment), efficient, and accurate screening of depression in the settings of primary care, psychiatric epidemiology, molecular genetics, and global health are all direct applications of the current system. © Copyright 2013 Physicians Postgraduate Press, Inc.

3-D Human body models in C.A.D. : Anthropometric Aspects

NASA Astrophysics Data System (ADS)

Renaud, C.; Steck, R.; Pineau, J. C.

1986-07-01

Modeling and simulation methods of man-machine systems are developed at the laboratory by interactive infography and C.A.D. technics. In order to better apprehend the morphological variability of populations we have enriched the 3-D model with a parametric function using classical anthropometric dimensions. We have selected reference, associate and complementary dimensions : lengths, breadths, circumferences and depths, which depend on operator's tasks and characteristics of workplaces. All anthropometric values come from the International Data Bank of Human Biometry of ERGODATA System. The utilization of the parametric function brings a quick and accurate description of morphology for theoretic subjects and can be used in C.A.D. analysis.

A terrain based simulation system to predict the interference caused by networks of spread spectrum systems

NASA Astrophysics Data System (ADS)

Hagen, William E.; Holtzman, Julian C.

The Army Terrain Integrated Interference Prediction System (ATIIPS), a CAD terrain based simulation tool for determining the degradation effects on a network on nonspread spectrum radios caused by a network of spread spectrum radios is presented. A brief overview of the program is given, with typical graphics displays shown. Typical results for both a link simulation of interference and for a network simulation, using a slow hopped FM/FSK spread spectrum interfering radio network on a narrow band FM/FSK fixed frequency digital radio are presented.

The Use of an Online Learning and Teaching System for Monitoring Computer Aided Design Student Participation and Predicting Student Success

ERIC Educational Resources Information Center

Akhtar, S.; Warburton, S.; Xu, W.

2017-01-01

In this paper we report on the use of a purpose built Computer Support Collaborative learning environment designed to support lab-based CAD teaching through the monitoring of student participation and identified predictors of success. This was carried out by analysing data from the interactive learning system and correlating student behaviour with…

Virtual Manufacturing (la Fabrication virtuelle)

DTIC Science & Technology

1998-05-01

with moving parts and subassemblies, • verification of product subcomponents and systems operations through kinematics studies, and • realism ...dimensions, parts moved in mechanism based directions, and realism of interaction is increased through use of sound, touch and other parameters. For the...direct converters from CAD systems. A simple cinematic package is also high on the requirement to be able to simulate motions as well as an interface to

A survey on computer aided diagnosis for ocular diseases

PubMed Central

2014-01-01

Background Computer Aided Diagnosis (CAD), which can automate the detection process for ocular diseases, has attracted extensive attention from clinicians and researchers alike. It not only alleviates the burden on the clinicians by providing objective opinion with valuable insights, but also offers early detection and easy access for patients. Method We review ocular CAD methodologies for various data types. For each data type, we investigate the databases and the algorithms to detect different ocular diseases. Their advantages and shortcomings are analyzed and discussed. Result We have studied three types of data (i.e., clinical, genetic and imaging) that have been commonly used in existing methods for CAD. The recent developments in methods used in CAD of ocular diseases (such as Diabetic Retinopathy, Glaucoma, Age-related Macular Degeneration and Pathological Myopia) are investigated and summarized comprehensively. Conclusion While CAD for ocular diseases has shown considerable progress over the past years, the clinical importance of fully automatic CAD systems which are able to embed clinical knowledge and integrate heterogeneous data sources still show great potential for future breakthrough. PMID:25175552

Development of an expert system for the simulation model for casting metal substructure of a metal-ceramic crown design.

PubMed

Matin, Ivan; Hadzistevic, Miodrag; Vukelic, Djordje; Potran, Michal; Brajlih, Tomaz

2017-07-01

Nowadays, the integrated CAD/CAE systems are favored solutions for the design of simulation models for casting metal substructures of metal-ceramic crowns. The worldwide authors have used different approaches to solve the problems using an expert system. Despite substantial research progress in the design of experts systems for the simulation model design and manufacturing have insufficiently considered the specifics of casting in dentistry, especially the need for further CAD, RE, CAE for the estimation of casting parameters and the control of the casting machine. The novel expert system performs the following: CAD modeling of the simulation model for casting, fast modeling of gate design, CAD eligibility and cast ability check of the model, estimation and running of the program code for the casting machine, as well as manufacturing time reduction of the metal substructure. The authors propose an integration method using common data model approach, blackboard architecture, rule-based reasoning and iterative redesign method. Arithmetic mean roughness values was determinated with constant Gauss low-pass filter (cut-off length of 2.5mm) according to ISO 4287 using Mahr MARSURF PS1. Dimensional deviation between the designed model and manufactured cast was determined using the coordinate measuring machine Zeiss Contura G2 and GOM Inspect software. The ES allows for obtaining the castings derived roughness grade number N7. The dimensional deviation between the simulation model of the metal substructure and the manufactured cast is 0.018mm. The arithmetic mean roughness values measured on the casting substructure are from 1.935µm to 2.778µm. The realized developed expert system with the integrated database is fully applicable for the observed hardware and software. Values of the arithmetic mean roughness and dimensional deviation indicate that casting substructures are surface quality, which is more than enough and useful for direct porcelain veneering. The manufacture of the substructure shows that the proposed ES allows the improvement of the design process while reducing the manufacturing time. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of different adhesives on work of adhesion between CAD/CAM polymers and resin composite cements.

PubMed

Keul, Christine; Müller-Hahl, Manuel; Eichberger, Marlis; Liebermann, Anja; Roos, Malgorzata; Edelhoff, Daniel; Stawarczyk, Bogna

2014-09-01

To determine the impact of pre-treatment of adhesive systems on the work of adhesion (WA) between CAD/CAM polymers and resin composite cements and compare with conventional tests of previous studies. Surface parameters were measured by contact angle measurement (2700 measurements) and WA was calculated. Five CAD/CAM polymers were used for fabrication of specimens (n=75/subgroup): artBloc Temp (A), Telio CAD (B), Nano Composite CFI-C (C), exp. CAD/CAM nanohybrid composite (D), and LAVA Ultimate (E). Then, air-abraded specimens were pre-treated (n=15 per group): Ambarino P60 (I), Monobond Plus/Heliobond (II), visio.link (III), VP connect (IV), and no pre-treatment (V). Resin composite cement specimens (n=75) were smoothed out homogeneously on a glass plate (n=15/group): RelyX ARC (RXA), Variolink II (VAR), Panavia F2.0 (PAN), RelyX Unicem (RXU), and Clearfil SA Cement (CSA). Contact angles were determined with 3 drops of distilled water and diiodomethane each. Data were analyzed using Kruskal-Wallis-H test and Spearman-Rho correlation (p<0.05). CAD/CAM materials (B), (A), and (C) showed higher WA compared to (D) and (E). (II) and (IV) resulted in higher WA than (I), (III) and (V). VAR had the significantly lowest WA, followed by RXU, RXA, CSA and PAN. No correlation occurred between WA and TBS/SBS whereas polar component of surface free energy of CAD/CAM resin and spreading coefficient showed significant positive correlation with TBS/SBS. Determination of WA is not a proper method to draw conclusions about the bond between resin materials. Destructive test methods are not dispensable. The successful outcome of fixed dental restorations depends, among others, on the quality of bonding between the tooth and the restoration. Additional pre-treatment of the dental CAD/CAM resin restoration by bonding systems can be recommended for clinical use. Pre-treatment showed a significant impact on the surface properties. Copyright © 2014 Elsevier Ltd. All rights reserved.