RESUMO
The global pandemic of coronavirus disease (COVID-19) has caused millions of deaths and affected the livelihood of many more people. Early and rapid detection of COVID-19 is a challenging task for the medical community, but it is also crucial in stopping the spread of the SARS-CoV-2 virus. Prior substantiation of artificial intelligence (AI) in various fields of science has encouraged researchers to further address this problem. Various medical imaging modalities including X-ray, computed tomography (CT) and ultrasound (US) using AI techniques have greatly helped to curb the COVID-19 outbreak by assisting with early diagnosis. We carried out a systematic review on state-of-the-art AI techniques applied with X-ray, CT, and US images to detect COVID-19. In this paper, we discuss approaches used by various authors and the significance of these research efforts, the potential challenges, and future trends related to the implementation of an AI system for disease detection during the COVID-19 pandemic.
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COVID-19 , Pandemias , Inteligência Artificial , Humanos , SARS-CoV-2 , Tomografia Computadorizada por Raios XRESUMO
BACKGROUND: Authors have been advocating the research ideology that a computer-aided diagnosis (CAD) system trained using lots of patient data and physiological signals and images based on adroit integration of advanced signal processing and artificial intelligence (AI)/machine learning techniques in an automated fashion can assist neurologists, neurosurgeons, radiologists, and other medical providers to make better clinical decisions. SUMMARY: This paper presents a state-of-the-art review of research on automated diagnosis of 5 neurological disorders in the past 2 decades using AI techniques: epilepsy, Parkinson's disease, Alzheimer's disease, multiple sclerosis, and ischemic brain stroke using physiological signals and images. Recent research articles on different feature extraction methods, dimensionality reduction techniques, feature selection, and classification techniques are reviewed. Key Message: CAD systems using AI and advanced signal processing techniques can assist clinicians in analyzing and interpreting physiological signals and images more effectively.
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Inteligência Artificial , Doenças do Sistema Nervoso Central/diagnóstico , Diagnóstico por Computador/métodos , Humanos , Processamento de Sinais Assistido por ComputadorRESUMO
Glaucoma is a type of eye condition which may result in partial or consummate vision loss. Higher intraocular pressure is the leading cause for this condition. Screening for glaucoma and early detection can avert vision loss. Computer aided diagnosis (CAD) is an automated process with the potential to identify glaucoma early through quantitative analysis of digital fundus images. Preparing an effective model for CAD requires a large database. This study presents a CAD tool for the precise detection of glaucoma using a machine learning approach. An autoencoder is trained to determine effective and important features from fundus images. These features are used to develop classes of glaucoma for testing. The method achieved an F - measure value of 0.95 utilizing 1426 digital fundus images (589 control and 837 glaucoma). The efficacy of the system is evident, and is suggestive of its possible utility as an additional tool for verification of clinical decisions.
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Técnicas de Diagnóstico Oftalmológico , Fundo de Olho , Interpretação de Imagem Assistida por Computador/métodos , Tomografia de Coerência Óptica/métodos , Adulto , Algoritmos , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reconhecimento Automatizado de Padrão/métodosRESUMO
The effect of titanium dioxide (TiO2 ) nanoparticles (NPs) on photophysical characteristics of 2,5-di[(E)-1-(4-dimethylaminophenyl) methylidine]-1-cyclopentanone (2,5-DMAPMC) and 2,5-di[(E)-1-(4-diethylaminophenyl)methylidine]-1-cyclopentanone (2,5-DEAPMC) ketocyanine dyes has been studied using absorption, steady-state and time-resolved fluorescence spectroscopy. The magnitudes of association constants determined based on modified absorption spectrum of dyes due to the presence of TiO2 NPs indicate the interaction of TiO2 NPs with dye molecules. The quenching of fluorescence intensity of dyes by TiO2 NPs is observed and it follows linear Stern-Volmer (S-V) equation. The magnitude of quenching rate parameter suggests the involvement of static quenching mechanism. The involvement of electron transfer process in reducing fluorescence intensity of dyes has been discussed. Also, varying influence of TiO2 NPs on two dyes is explained based on the presence of different alkyl substituent in two dyes.
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Corantes/química , Ciclopentanos/química , Nanopartículas/química , Titânio/química , Fluorescência , Espectrometria de Fluorescência , Espectrofotometria UltravioletaRESUMO
The effect of solvents of varying polarity and hydrogen bonding ability, solvent mixture and silver nanoparticles on the photophysical properties of a ketocyanine dye, 2,5-di[(E)-1-(4-diethylaminophenyl) methylidine]-1-cyclopentanone (2,5-DEAPMC), is investigated at room temperature. Solvent effect is analyzed using Lippert-Mataga bulk polarity function, Reichardt's microscopic solvent polarity parameter, and Kamlet's and Catalan's multiple linear regression approaches. The spectral properties better follow Reichardt's microscopic solvent polarity parameter than the Lippert-Mataga bulk polarity function. This indicates that both general and specific solute-solvent interactions are operative. Kamlet's and Catalan's multiple linear regression approaches indicate that polarizability/dipolarity solvent influences are greater than hydrogen bond donor and hydrogen bond acceptor solvent influences. The solvatochromic correlations are used to estimate excited state dipole moment using the experimentally determined ground state dipole moment. The excited state dipole moment of the dye is found to be larger than its corresponding ground state dipole moment and ground and excited state dipole moments are not parallel, but subtend an angle of 77°. The absorption and emission spectra are modulated in the presence silver nanoparticles. The fluorescence of 2,5-DEAPMC is quenched by silver nanoparticles. The possible fluorescence quenching mechanisms are discussed. Copyright © 2016 John Wiley & Sons, Ltd.
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Ciclopentanos/química , Corantes Fluorescentes/química , Nanopartículas Metálicas/química , Prata/química , Ligação de Hidrogênio , Processos Fotoquímicos , Solventes/químicaRESUMO
Brinjal (Solanum melongena L.) var. Mattu Gulla (MG) and var. Perampalli Gulla (PG) are unique varieties with distinct flavour cultivated in Udupi, Karnataka State, and are exposed to several biotic and abiotic stresses. An efficient and reproducible in vitro regeneration method is required to expedite the manipulation of these brinjal varieties to cope up with stress by tissue culture and gene transfer methods. The present study, reports a rapid and efficient in vitro regeneration protocol for these two varieties. The in vitro growth response was studied on Murashige and Skoog (MS) medium supplemented with 2, 4-D, BAP and IAA, and the plantlets were regenerated efficiently from callus cultures of leaf, cotyledon and hypocotyl explants. Among the three explants, the hypocotyl explants were found to have better callus induction and multiple shoot regeneration. High frequency of shoot initiation was achieved from hypocotyl derived calluses in MS media with 2.0 mg/L BAP and 0.5 mg/L IAA in MG and PG. Efficient and rapid shoot proliferation, and elongation were noted in MS medium with 1.0 mg/L BAP and 0.3 mg/L GA3. The in vitro regenerated shoots produced healthy roots when they were cultured on MS medium supplemented with 0.5 mg/L IBA. A significant difference was observed in percentage of callus induction, number of shoots per callus, shoot elongation and number of hardened plantlets of MG and PG. MG showed maximum response in all stages of culture than PG. Hardening of plantlets in tissue culture was achieved in three weeks. The hardened plantlets were grown in pots for further acclimatization in green house and finally transplanted to experimental garden where they developed into flowering plants and produced mature fruits with viable seeds.
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Reguladores de Crescimento de Plantas/farmacologia , Brotos de Planta/crescimento & desenvolvimento , Regeneração/fisiologia , Sementes/crescimento & desenvolvimento , Solanum melongena/crescimento & desenvolvimento , Técnicas de Cultura de Células , Cotilédone/citologia , Cotilédone/crescimento & desenvolvimento , Meios de Cultura , Índia , Folhas de Planta/citologia , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/citologia , Raízes de Plantas/crescimento & desenvolvimento , Brotos de Planta/citologia , Sementes/citologiaRESUMO
Artificial Intelligence (AI) techniques are increasingly used in computer-aided diagnostic tools in medicine. These techniques can also help to identify Hypertension (HTN) in its early stage, as it is a global health issue. Automated HTN detection uses socio-demographic, clinical data, and physiological signals. Additionally, signs of secondary HTN can also be identified using various imaging modalities. This systematic review examines related work on automated HTN detection. We identify datasets, techniques, and classifiers used to develop AI models from clinical data, physiological signals, and fused data (a combination of both). Image-based models for assessing secondary HTN are also reviewed. The majority of the studies have primarily utilized single-modality approaches, such as biological signals (e.g., electrocardiography, photoplethysmography), and medical imaging (e.g., magnetic resonance angiography, ultrasound). Surprisingly, only a small portion of the studies (22 out of 122) utilized a multi-modal fusion approach combining data from different sources. Even fewer investigated integrating clinical data, physiological signals, and medical imaging to understand the intricate relationships between these factors. Future research directions are discussed that could build better healthcare systems for early HTN detection through more integrated modeling of multi-modal data sources.
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Hipertensão , Medicina , Humanos , Inteligência Artificial , Eletrocardiografia , Hipertensão/diagnóstico por imagem , Angiografia por Ressonância MagnéticaRESUMO
A brain tumor is an abnormal mass of tissue located inside the skull. In addition to putting pressure on the healthy parts of the brain, it can lead to significant health problems. Depending on the region of the brain tumor, it can cause a wide range of health issues. As malignant brain tumors grow rapidly, the mortality rate of individuals with this cancer can increase substantially with each passing week. Hence it is vital to detect these tumors early so that preventive measures can be taken at the initial stages. Computer-aided diagnostic (CAD) systems, in coordination with artificial intelligence (AI) techniques, have a vital role in the early detection of this disorder. In this review, we studied 124 research articles published from 2000 to 2022. Here, the challenges faced by CAD systems based on different modalities are highlighted along with the current requirements of this domain and future prospects in this area of research.
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Inteligência Artificial , Neoplasias Encefálicas , Humanos , Encéfalo , Neoplasias Encefálicas/diagnóstico , Crânio , Compostos RadiofarmacêuticosRESUMO
BACKGROUND: Human emotions greatly affect the actions of a person. The automated emotion recognition has applications in multiple domains such as health care, e-learning, surveillance, etc. The development of computer-aided diagnosis (CAD) tools has led to the automated recognition of human emotions. OBJECTIVE: This review paper provides an insight into various methods employed using electroencephalogram (EEG), facial, and speech signals coupled with multi-modal emotion recognition techniques. In this work, we have reviewed most of the state-of-the-art papers published on this topic. METHOD: This study was carried out by considering the various emotion recognition (ER) models proposed between 2016 and 2021. The papers were analysed based on methods employed, classifier used and performance obtained. RESULTS: There is a significant rise in the application of deep learning techniques for ER. They have been widely applied for EEG, speech, facial expression, and multimodal features to develop an accurate ER model. CONCLUSION: Our study reveals that most of the proposed machine and deep learning-based systems have yielded good performances for automated ER in a controlled environment. However, there is a need to obtain high performance for ER even in an uncontrolled environment.
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Eletroencefalografia , Expressão Facial , Emoções , Humanos , FalaRESUMO
Hypertrophic cardiomyopathy (HCM) is a genetic disorder that exhibits a wide spectrum of clinical presentations, including sudden death. Early diagnosis and intervention may avert the latter. Left ventricular hypertrophy on heart imaging is an important diagnostic criterion for HCM, and the most common imaging modality is heart ultrasound (US). The US is operator-dependent, and its interpretation is subject to human error and variability. We proposed an automated computer-aided diagnostic tool to discriminate HCM from healthy subjects on US images. We used a local directional pattern and the ResNet-50 pretrained network to classify heart US images acquired from 62 known HCM patients and 101 healthy subjects. Deep features were ranked using Student's t-test, and the most significant feature (SigFea) was identified. An integrated index derived from the simulation was defined as 100·log10(SigFea/2) in each subject, and a diagnostic threshold value was empirically calculated as the mean of the minimum and maximum integrated indices among HCM and healthy subjects, respectively. An integrated index above a threshold of 0.5 separated HCM from healthy subjects with 100% accuracy in our test dataset.
RESUMO
Cardiac pacemakers are used in the treatment of patients with symptomatic bradycardia. The pacemaker paces the heart at the predetermined rate to maintain uninterrupted cardiac activity. Usually, pacemaker lead will be connected to the right atrium (RA) and right ventricle (RV) in dual-chamber pacemaker implantation and RV alone in single-chamber pacemaker implantation. This alters the route of proper conduction across the myocardial cells. The cell-to-cell conduction transmission in pacing delays the activation of selected intraventricular myocardial activation. Pacing-induced cardiomyopathy (PICM) is most commonly defined as a drop in left ventricle ejection fraction (LVEF) in the setting of chronic, high-burden right ventricle (RV) pacing. Currently, very few effective treatments are standard for PICM which rely on the detection of the RV pacing. Such treatments have primarily focused on upgrading to cardiac resynchronization therapy (CRT) when LVEF has dropped. However, the early and accurate detection of these stress factors is challenging. Cardiac desynchrony and interventricular desynchrony can be determined by various echocardiographic techniques, including M-mode, Doppler method, tissue Doppler method, and speckle tracking echocardiography which is subjective measures and shows a significant difference between RV and LV preejection period where the activation of LV is delayed considerably. Computer-aided diagnosis (CAD) is a noninvasive technique that can classify the ultrasound images of the heart in pacemaker-implanted patients and healthy patients with normal left ventricular systolic function and further detect the variations in pacemaker functions in its early stage using heart ultrasound images. Developing such a system requires a vast and diverse database to reach optimum performance. This paper proposes a novel CAD tool for the accurate detection of pacemaker variations using machine learning models of decision tree, SVM, random forest, and AdaBoost. The models have been used to extract radiomics features in terms of textures and then screened by their Relief-F scores for selection and ranking to be classified into nine groups consisting of up to 250 radiomics features. Ten best features were fed to the machine learning models. The R-wave dataset achieved a maximum test performance accuracy of 97.73% with four features in the random forest model. The T-wave dataset achieved a maximum test performance accuracy of 96.59% with three features in the SVM model. Our experimental results demonstrate the system's robustness, which can be developed as an early and accurate detection system for pacing-induced cardiomyopathy.
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Terapia de Ressincronização Cardíaca , Cardiomiopatias , Cardiopatias Congênitas , Estimulação Cardíaca Artificial/efeitos adversos , Estimulação Cardíaca Artificial/métodos , Terapia de Ressincronização Cardíaca/métodos , Cardiomiopatias/diagnóstico por imagem , Cardiomiopatias/etiologia , Cardiomiopatias/terapia , Ventrículos do Coração/diagnóstico por imagem , Humanos , Volume Sistólico/fisiologia , Resultado do Tratamento , Função Ventricular Esquerda/fisiologiaRESUMO
Hypertension (HTN) is a major risk factor for cardiovascular diseases. At least 45% of deaths due to heart disease and 51% of deaths due to stroke are the result of hypertension. According to research on the prevalence and absolute burden of HTN in India, HTN positively correlated with age and was present in 20.6% of men and 20.9% of women. It was estimated that this trend will increase to 22.9% and 23.6% for men and women, respectively, by 2025. Controlling blood pressure is therefore important to lower both morbidity and mortality. Computer-aided diagnosis (CAD) is a noninvasive technique which can determine subtle myocardial structural changes at an early stage. In this work, we show how a multi-resolution analysis-based CAD system can be utilized for the detection of early HTN-induced left ventricular heart muscle changes with the help of ultrasound imaging. Firstly, features were extracted from the ultrasound imagery, and then the feature dimensions were reduced using a locality sensitive discriminant analysis (LSDA). The decision tree classifier with contourlet and shearlet transform features was later employed for improved performance and maximized accuracy using only two features. The developed model is applicable for the evaluation of cardiac structural alteration in HTN and can be used as a standalone tool in hospitals and polyclinics.
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Hipertensão , Pressão Sanguínea/fisiologia , Feminino , Ventrículos do Coração/diagnóstico por imagem , Humanos , Hipertensão/diagnóstico por imagem , Hipertensão/epidemiologia , Masculino , Miocárdio , Ultrassonografia/métodosRESUMO
Traumatic brain injury (TBI) occurs due to the disruption in the normal functioning of the brain by sudden external forces. The primary and secondary injuries due to TBI include intracranial hematoma (ICH), raised intracranial pressure (ICP), and midline shift (MLS), which can result in significant lifetime disabilities and death. Hence, early diagnosis of TBI is crucial to improve patient outcome. Computed tomography (CT) is the preferred modality of choice to assess the severity of TBI. However, manual visualization and inspection of hematoma and its complications from CT scans is a highly operator-dependent and time-consuming task, which can lead to an inappropriate or delayed prognosis. The development of computer aided diagnosis (CAD) systems could be helpful for accurate, early management of TBI. In this paper, a systematic review of prevailing CAD systems for the detection of hematoma, raised ICP, and MLS in non-contrast axial CT brain images is presented. We also suggest future research to enhance the performance of CAD for early and accurate TBI diagnosis.
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Lesões Encefálicas Traumáticas , Lesões Encefálicas , Encéfalo , Lesões Encefálicas Traumáticas/diagnóstico por imagem , Humanos , Pressão Intracraniana , Tomografia Computadorizada por Raios XRESUMO
Coronary artery disease is a major cause of morbidity and mortality worldwide. Its underlying histopathology is the atherosclerotic plaque, which comprises lipid, fibrous and-when chronic-calcium components. Intravascular ultrasound (IVUS) and intravascular optical coherence tomography (IVOCT) performed during invasive coronary angiography are reference standards for characterizing the atherosclerotic plaque. Fine image spatial resolution attainable with contemporary coronary computed tomographic angiography (CCTA) has enabled noninvasive plaque assessment, including identifying features associated with vulnerable plaques known to presage acute coronary events. Manual interpretation of IVUS, IVOCT and CCTA images demands scarce physician expertise and high time cost. This has motivated recent research into and development of artificial intelligence (AI)-assisted methods for image processing, feature extraction, plaque identification and characterization. We performed parallel searches of the medical and technical literature from 1995 to 2021 focusing respectively on human plaque characterization using various imaging modalities and the use of AI-assisted computer aided diagnosis (CAD) to detect and classify atherosclerotic plaques, including their composition and the presence of high-risk features denoting vulnerable plaques. A total of 122 publications were selected for evaluation and the analysis was summarized in terms of data sources, methods-machine versus deep learning-and performance metrics. Trends in AI-assisted plaque characterization are detailed and prospective research challenges discussed. Future directions for the development of accurate and efficient CAD systems to characterize plaque noninvasively using CCTA are proposed.
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Doença da Artéria Coronariana , Placa Aterosclerótica , Inteligência Artificial , Angiografia Coronária , Doença da Artéria Coronariana/diagnóstico por imagem , Humanos , Placa Aterosclerótica/diagnóstico por imagem , Estudos ProspectivosRESUMO
Computer aided diagnostic (CAD) has become a significant tool in expanding patient quality-of-life by reducing human errors in diagnosis. CAD can expedite decision-making on complex clinical data automatically. Since brain diseases can be fatal, rapid identification of brain pathology to prolong patient life is an important research topic. Many algorithms have been proposed for efficient brain pathology identification (BPI) over the past decade. Constant refinement of the various image processing algorithms must take place to expand performance of the automatic BPI task. In this paper, a systematic survey of contemporary BPI algorithms using brain magnetic resonance imaging (MRI) is presented. A summarization of recent literature provides investigators with a helpful synopsis of the domain. Furthermore, to enhance the performance of BPI, future research directions are indicated.
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Encefalopatias/diagnóstico por imagem , Neoplasias Encefálicas/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Aprendizado Profundo , Diagnóstico por Computador/métodos , Algoritmos , Doença de Alzheimer/diagnóstico por imagem , Computadores , Demência Vascular/diagnóstico por imagem , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética , Redes Neurais de Computação , Neuroimagem , Sarcoma/diagnóstico por imagemRESUMO
Retinal detachment (RD) is an ocular emergency, which needs quick intervention to preclude permanent vision loss. In general, ocular ultrasound is used by ophthalmologists to enhance their judgment in detecting RD in eyes with media opacities which precludes the retinal evaluation. However, the quality of ultrasound (US) images may be degraded due to the presence of noise, and other retinal conditions may cause membranous echoes. All these can influence the accuracy of diagnosis. Hence, to overcome the above, we are proposing an automated system to detect RD using texton, higher order spectral (HOS) cumulants and locality sensitive discriminant analysis (LSDA) techniques. Our developed method is able to classify the posterior vitreous detachment and RD using support vector machine classifier with highest accuracy of 99.13%. Our system is ready to be tested with more diverse ultrasound images and aid ophthalmologists to arrive at a more accurate diagnosis.
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Descolamento Retiniano , Descolamento do Vítreo , Serviço Hospitalar de Emergência , Humanos , Retina , Descolamento Retiniano/diagnóstico por imagem , UltrassonografiaRESUMO
BACKGROUND: Molecular-scale mechanisms of the enzymatic breakdown of cellulosic biomass into fermentable sugars are still poorly understood, with a need for independent measurements of enzyme kinetic parameters. We measured binding times of cellobiohydrolase Trichoderma reesei Cel7A (Cel7A) on celluloses using wild-type Cel7A (WTintact), the catalytically deficient mutant Cel7A E212Q (E212Qintact) and their proteolytically isolated catalytic domains (CD) (WTcore and E212Qcore, respectively). The binding time distributions were obtained from time-resolved, super-resolution images of fluorescently labeled enzymes on cellulose obtained with total internal reflection fluorescence microscopy. RESULTS: Binding of WTintact and E212Qintact on the recalcitrant algal cellulose (AC) showed two bound populations: ~ 85% bound with shorter residence times of < 15 s while ~ 15% were effectively immobilized. The similarity between binding times of the WT and E212Q suggests that the single point mutation in the enzyme active site does not affect the thermodynamics of binding of this enzyme. The isolated catalytic domains, WTcore and E212Qcore, exhibited three binding populations on AC: ~ 75% bound with short residence times of ~ 15 s (similar to the intact enzymes), ~ 20% bound for < 100 s and ~ 5% that were effectively immobilized. CONCLUSIONS: Cel7A binding to cellulose is driven by the interactions between the catalytic domain and cellulose. The cellulose-binding module (CBM) and linker increase the affinity of Cel7A to cellulose likely by facilitating recognition and complexation at the substrate interface. The increased affinity of Cel7A to cellulose by the CBM and linker comes at the cost of increasing the population of immobilized enzyme on cellulose. The residence time (or inversely the dissociation rates) of Cel7A on cellulose is not catalysis limited.
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Atherosclerosis is a type of cardiovascular disease which may cause stroke. It is due to the deposition of fatty plaque in the artery walls resulting in the reduction of elasticity gradually and hence restricting the blood flow to the heart. Hence, an early prediction of carotid plaque deposition is important, as it can save lives. This paper proposes a novel data mining framework for the assessment of atherosclerosis in its early stage using ultrasound images. In this work, we are using 1353 symptomatic and 420 asymptomatic carotid plaque ultrasound images. Our proposed method classifies the symptomatic and asymptomatic carotid plaques using bidimensional empirical mode decomposition (BEMD) and entropy features. The unbalanced data samples are compensated using adaptive synthetic sampling (ADASYN), and the developed method yielded a promising accuracy of 91.43%, sensitivity of 97.26%, and specificity of 83.22% using fourteen features. Hence, the proposed method can be used as an assisting tool during the regular screening of carotid arteries in hospitals. Graphical abstract Outline for our efficient data mining framework for the characterization of symptomatic and asymptomatic carotid plaques.
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Algoritmos , Artérias Carótidas/patologia , Mineração de Dados , Placa Aterosclerótica/patologia , Artérias Carótidas/diagnóstico por imagem , Entropia , Humanos , Placa Aterosclerótica/diagnóstico por imagem , Curva ROC , Máquina de Vetores de Suporte , UltrassomRESUMO
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.
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Bases de Dados Factuais , Diagnóstico por Computador/métodos , Processamento de Imagem Assistida por Computador/métodos , Máquina de Vetores de Suporte , Nódulo da Glândula Tireoide/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , UltrassonografiaRESUMO
BACKGROUND AND OBJECTIVE: Liver fibrosis is a type of chronic liver injury that is characterized by an excessive deposition of extracellular matrix protein. Early detection of liver fibrosis may prevent further growth toward liver cirrhosis and hepatocellular carcinoma. In the past, the only method to assess liver fibrosis was through biopsy, but this examination is invasive, expensive, prone to sampling errors, and may cause complications such as bleeding. Ultrasound-based elastography is a promising tool to measure tissue elasticity in real time; however, this technology requires an upgrade of the ultrasound system and software. In this study, a novel computer-aided diagnosis tool is proposed to automatically detect and classify the various stages of liver fibrosis based upon conventional B-mode ultrasound images. METHODS: The proposed method uses a 2D contourlet transform and a set of texture features that are efficiently extracted from the transformed image. Then, the combination of a kernel discriminant analysis (KDA)-based feature reduction technique and analysis of variance (ANOVA)-based feature ranking technique was used, and the images were then classified into various stages of liver fibrosis. RESULTS: Our 2D contourlet transform and texture feature analysis approach achieved a 91.46% accuracy using only four features input to the probabilistic neural network classifier, to classify the five stages of liver fibrosis. It also achieved a 92.16% sensitivity and 88.92% specificity for the same model. The evaluation was done on a database of 762 ultrasound images belonging to five different stages of liver fibrosis. CONCLUSIONS: The findings suggest that the proposed method can be useful to automatically detect and classify liver fibrosis, which would greatly assist clinicians in making an accurate diagnosis.