RESUMO
Transposition of the great arteries (TGA) is a cyanotic congenital heart disease characterized by ventriculoarterial discordance and atrioventricular concordance with the great arteries in a parallel relationship. Prenatal diagnosis of TGA has implications for postnatal outcomes, allowing for planned delivery and perinatal management. Three-dimensional virtual or physical models of fetal TGA allow better understanding of fetal cardiac anomalies by parents and interactive discussion among the multidisciplinary team (obstetricians, pediatricians, maternal-fetal specialists, pediatric cardiologists, and cardiovascular surgeons), as well as continuing medical education.
Assuntos
Coração Fetal , Valor Preditivo dos Testes , Transposição dos Grandes Vasos , Ultrassonografia Pré-Natal , Transposição dos Grandes Vasos/diagnóstico por imagem , Transposição dos Grandes Vasos/cirurgia , Transposição dos Grandes Vasos/fisiopatologia , Humanos , Gravidez , Coração Fetal/diagnóstico por imagem , Coração Fetal/fisiopatologia , Feminino , Imageamento Tridimensional , Modelos Cardiovasculares , Idade Gestacional , Modelagem Computacional Específica para o Paciente , Prognóstico , Interpretação de Imagem Assistida por ComputadorRESUMO
BACKGROUND: When approaching a joint replacement procedure, pre-surgical planning is essential to predict an accurate estimation of implant size and position. There are currently two methods to achieve it, analog and digital. The present study aims to demonstrate how the hybrid technique is accurate and precise for pre-surgical planning in a non-cemented total hip replacement. METHODS: Concordance-type study is used against a gold standard, as well as inter- and intra-observer consistency evaluation of two orthopedic surgeons and two orthopedic surgery residents. Accuracy was calculated with the intra-class correlation coefficient (ICC). Afterwards, the same calculation was done considering a margin of error with one size more and one less. RESULTS: Thirty-eight patients were included in the study: 19 women and 19 men. Twenty-two prostheses (57.89%) were right-sided and 16 were left (42.11%). Twelve prostheses (31.57%) were Stryker and 26 Johnson & Johnson (68.43%). Acetabular cup correlation compared with the gold standard was moderate: ICC reported 0.45 (95% CI, 0.15-0.76). When adjusted by ± 1 size, ICC was 0.48 (95% CI, 0.18-0.79). On the other hand, results from the femoral stem reported ICC 0.85 (95% CI, 0.07-0.98). When adjusted by ± 1 size, ICC was 0.86 (95% CI, 0.06-0.99). CONCLUSIONS: Hybrid templating is a reliable substitute for analog or digital planning. It is quick, inexpensive, accurate, and better results are observed in the femoral component regardless the level of expertise of the evaluator. LEVEL OF EVIDENCE: Grade IV.
Assuntos
Artroplastia de Quadril , Prótese de Quadril , Processamento de Imagem Assistida por Computador/métodos , Medicina de Precisão/métodos , Cuidados Pré-Operatórios/métodos , Desenho de Prótese/métodos , Acetábulo/cirurgia , Acetatos , Feminino , Fêmur/cirurgia , Humanos , Masculino , Variações Dependentes do Observador , Osteoartrite do Quadril/cirurgia , Modelagem Computacional Específica para o Paciente , Técnicas de Planejamento , Reprodutibilidade dos Testes , Estudos RetrospectivosRESUMO
BACKGROUND: Surgical mobilization of the maxillary segment affects nasal morphology. This study assessed the impact of the type of maxillary mobilization on the three-dimensional (3D) nasal morphometry. METHODS: Pre- and postsurgery cone beam computed tomography-derived facial image datasets of consecutive patients who underwent two-jaw orthognathic surgery were reviewed. Using preoperative 3D facial models as the positional reference of the skeletal framework, 12-month postoperative 3D facial models were classified into four types of maxillary mobilizations (advancement [nâ¯=â¯83], setback [nâ¯=â¯24], intrusion [nâ¯=â¯55], and extrusion [nâ¯=â¯52]) and four types of final maxillary positions (anterosuperior [nâ¯=â¯44], anteroinferior [nâ¯=â¯39], posterosuperior [nâ¯=â¯11], and posteroinferior [nâ¯=â¯13]). Six 3D soft tissue nasal morphometric parameters were measured, with excellent intra- and interexaminer reliability scores (ICC>0.897) for all the measurements. The 3D nasal change for each nasal parameter was computed as the difference between postoperative and preoperative measurement values. RESULTS: The intrusion maxillary mobilization resulted in a significantly (all p<0.05) larger 3D nasal change in terms of alar width, alar base width, and nostril angle parameters, and a smaller change in terms of the nasal tip height parameter than the extrusion maxillary mobilization; however, no significant (all p>0.05) difference was observed between advancement and setback maxillary mobilizations. The anterosuperior and posterosuperior maxillary positions had a significantly (all p<0.05) larger 3D nasal change in terms of the alar base width and nostril angle than the anteroinferior and posteroinferior maxillary positions. CONCLUSION: The type of maxillary mobilization affects the 3D nasal morphometry.
Assuntos
Maxila , Nariz , Procedimentos Cirúrgicos Ortognáticos , Osteotomia de Le Fort , Modelagem Computacional Específica para o Paciente , Adulto , Tomografia Computadorizada de Feixe Cônico/métodos , Feminino , Humanos , Imageamento Tridimensional/métodos , Masculino , Maxila/diagnóstico por imagem , Maxila/cirurgia , Nariz/diagnóstico por imagem , Nariz/patologia , Procedimentos Cirúrgicos Ortognáticos/efeitos adversos , Procedimentos Cirúrgicos Ortognáticos/métodos , Osteotomia de Le Fort/efeitos adversos , Osteotomia de Le Fort/métodos , Fotogrametria/métodos , Cuidados Pré-Operatórios/métodos , Período Pré-Operatório , Reprodutibilidade dos TestesRESUMO
Electromagnetic source imaging (ESI) techniques have become one of the most common alternatives for understanding cognitive processes in the human brain and for guiding possible therapies for neurological diseases. However, ESI accuracy strongly depends on the forward model capabilities to accurately describe the subject's head anatomy from the available structural data. Attempting to improve the ESI performance, we enhance the brain structure model within the individual-defined forward problem formulation, combining the head geometry complexity of the modeled tissue compartments and the prior knowledge of the brain tissue morphology. We validate the proposed methodology using 25 subjects, from which a set of magnetic-resonance imaging scans is acquired, extracting the anatomical priors and an electroencephalography signal set needed for validating the ESI scenarios. Obtained results confirm that incorporating patient-specific head models enhances the performed accuracy and improves the localization of focal and deep sources.
Assuntos
Eletroencefalografia/métodos , Cabeça/anatomia & histologia , Cabeça/diagnóstico por imagem , Modelagem Computacional Específica para o Paciente/estatística & dados numéricos , Adolescente , Encéfalo/anatomia & histologia , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico/métodos , Mapeamento Encefálico/estatística & dados numéricos , Criança , Pré-Escolar , Biologia Computacional , Eletroencefalografia/estatística & dados numéricos , Fenômenos Eletromagnéticos , Humanos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Modelos Neurológicos , Neuroimagem/estatística & dados numéricosRESUMO
Objective To evaluate the influence of three levels of dental structure loss on stress distribution and bite load in root canal-treated young molar teeth that were filled with bulk-fill resin composite, using finite element analysis (FEA) to predict clinical failure. Methodology Three first mandibular molars with extensive caries lesions were selected in teenager patients. The habitual occlusion bite force was measured using gnathodynamometer before and after endodontic/restoration procedures. The recorded bite forces were used as input for patient-specific FEA models, generated from cone-beam computed tomographic (CT) scans of the teeth before and after treatment. Loads were simulated using the contact loading of the antagonist molars selected based on the CT scans and clinical evaluation. Pre and post treatment bite forces (N) in the 3 patients were 30.1/136.6, 34.3/133.4, and 47.9/124.1. Results Bite force increased 260% (from 36.7±11.6 to 131.9±17.8 N) after endodontic and direct restoration. Before endodontic intervention, the stress concentration was located in coronal tooth structure; after rehabilitation, the stresses were located in root dentin, regardless of the level of tooth structure loss. The bite force used on molar teeth after pulp removal during endodontic treatment resulted in high stress concentrations in weakened tooth areas and at the furcation. Conclusion Extensive caries negatively affected the bite force. After pulp removal and endodontic treatment, stress and strain concentrations were higher in the weakened dental structure. Root canal treatment associated with direct resin composite restorative procedure could restore the stress-strain conditions in permanent young molar teeth.
Assuntos
Força de Mordida , Resinas Compostas/química , Resinas Compostas/uso terapêutico , Restauração Dentária Permanente/métodos , Dente Molar , Dente não Vital/terapia , Criança , Força Compressiva , Tomografia Computadorizada de Feixe Cônico , Análise do Estresse Dentário , Módulo de Elasticidade , Análise de Elementos Finitos , Humanos , Modelagem Computacional Específica para o Paciente , Valores de Referência , Reprodutibilidade dos Testes , Resistência à Tração , Dente não Vital/diagnóstico por imagem , Resultado do TratamentoRESUMO
Predictive models can be useful in predicting patient outcomes under uncertainty. Many algorithms employ "population" methods, which optimize a single model to perform well on average over an entire population, but the model may perform poorly on some patients. Personalized methods optimize predictive performance for each patient by tailoring the model to the individual. We present a new personalized method based on decision trees: the Personalized Decision Path using a Bayesian score (PDP-Bay). Performance on eight synthetic, genomic, and clinical datasets was compared to that of decision trees and a previously described personalized decision path method in terms of area under the ROC curve (AUC) and expected calibration error (ECE). Model complexity was measured by average path length. The PDP-Bay model outperformed the decision tree in terms of both AUC and ECE. The results support the conclusion that personalization may achieve better predictive performance and produce simpler models than population approaches.
Assuntos
Árvores de Decisões , Modelagem Computacional Específica para o Paciente , Algoritmos , Área Sob a Curva , Teorema de Bayes , Humanos , Masculino , Prognóstico , Curva ROC , IncertezaRESUMO
Abstract Objective To evaluate the influence of three levels of dental structure loss on stress distribution and bite load in root canal-treated young molar teeth that were filled with bulk-fill resin composite, using finite element analysis (FEA) to predict clinical failure. Methodology Three first mandibular molars with extensive caries lesions were selected in teenager patients. The habitual occlusion bite force was measured using gnathodynamometer before and after endodontic/restoration procedures. The recorded bite forces were used as input for patient-specific FEA models, generated from cone-beam computed tomographic (CT) scans of the teeth before and after treatment. Loads were simulated using the contact loading of the antagonist molars selected based on the CT scans and clinical evaluation. Pre and post treatment bite forces (N) in the 3 patients were 30.1/136.6, 34.3/133.4, and 47.9/124.1. Results Bite force increased 260% (from 36.7±11.6 to 131.9±17.8 N) after endodontic and direct restoration. Before endodontic intervention, the stress concentration was located in coronal tooth structure; after rehabilitation, the stresses were located in root dentin, regardless of the level of tooth structure loss. The bite force used on molar teeth after pulp removal during endodontic treatment resulted in high stress concentrations in weakened tooth areas and at the furcation. Conclusion Extensive caries negatively affected the bite force. After pulp removal and endodontic treatment, stress and strain concentrations were higher in the weakened dental structure. Root canal treatment associated with direct resin composite restorative procedure could restore the stress-strain conditions in permanent young molar teeth.
Assuntos
Humanos , Criança , Força de Mordida , Resinas Compostas/química , Dente não Vital/terapia , Restauração Dentária Permanente/métodos , Dente Molar , Valores de Referência , Resistência à Tração , Reprodutibilidade dos Testes , Resultado do Tratamento , Resinas Compostas/uso terapêutico , Dente não Vital/diagnóstico por imagem , Força Compressiva , Análise de Elementos Finitos , Análise do Estresse Dentário , Tomografia Computadorizada de Feixe Cônico , Módulo de Elasticidade , Modelagem Computacional Específica para o PacienteRESUMO
Image quality in positron emission tomography (PET) is limited by the number of detected photons. Heavier patients present higher photon attenuation levels, thus increasing image noise. In this work, we propose a new method that uses the combined patient attenuation/system matrix together with a tracer uptake prediction model to optimize scan times for different bed positions in whole body scans. Our main goal is to achieve consistent noise levels across patients and anatomical regions. We propose to optimize scan times for individual bed positions, for patients of any size, based on the scanner sensitivity and patient-specific attenuation. Variable scan times for every bed position were determined by combining the system matrix, derived from the computed tomography (CT) and the scanner-specific geometric sensitivity profiles, and estimations of the global tracer uptake for each patient. The method was validated with anthropomorphic phantoms and whole-body patient 18F-FDG PET/CT scans, where variable and fixed times were compared. Phantom experiments showed that the proposed method was successful in keeping noise level constant for different attenuation setups. In real patients, image noise variability was reduced to less than one-half compared with conventional fixed-time scans at the expense of a four-fold increase in scan times between the biggest and smallest patients. Our method can homogenize image quality not only across patients of different sizes but also across different bed positions of the same patient.
Assuntos
Modelagem Computacional Específica para o Paciente , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Imagem Corporal Total/métodos , Fluordesoxiglucose F18 , Humanos , Imagens de Fantasmas , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/normas , Compostos Radiofarmacêuticos , Razão Sinal-Ruído , Tempo , Imagem Corporal Total/normasRESUMO
INTRODUCTION: Three-dimensional (3D) printing has become an affordable tool for assisting heart surgeons in the aorta endovascular field, both in surgical planning, education and training of residents and students. This technique permits the construction of physical prototypes from conventional medical images by converting the anatomical information into computer aided design (CAD) files. OBJECTIVE: To present the 3D printing feature on developing prototypes leading to improved aortic endovascular surgical planning, as well as transcatheter aortic valve implantation, and mainly enabling training of the surgical procedure to be performed on patient's specific condition. METHODS: Six 3D printed real scale prototypes were built representing different aortic diseases, taken from real patients, to simulate the correction of the disease with endoprosthesis deployment. RESULTS: In the hybrid room, the 3D prototypes were examined under fluoroscopy, making it possible to obtain images that clearly delimited the walls of the aorta and its details. The endovascular simulation was then able to be performed, by correctly positioning the endoprosthesis, followed by its deployment. CONCLUSION: The 3D printing allowed the construction of aortic diseases realistic prototypes, offering a 3D view from the two-dimensional image of computed tomography (CT) angiography, allowing better surgical planning and surgeon training in the specific case beforehand.
Assuntos
Doenças da Aorta/cirurgia , Procedimentos Endovasculares , Modelagem Computacional Específica para o Paciente , Cuidados Pré-Operatórios/métodos , Impressão Tridimensional , Idoso , Doenças da Aorta/diagnóstico por imagem , Angiografia por Tomografia Computadorizada , Feminino , Humanos , Masculino , Resultado do TratamentoRESUMO
Ectopic beats are known to be involved in the initiation of a variety of cardiac arrhythmias. Although their location may vary, ectopic excitations have been found to originate from infarct areas, regions of micro-fibrosis and other heterogeneous tissues. However, the underlying mechanisms that link ectopic foci to heterogeneous tissues have yet to be fully understood. In this work, we investigate the mechanism of micro-reentry that leads to the generation of ectopic beats near infarct areas using a patient-specific heart model. The patient-specific geometrical model of the heart, including scar and peri-infarct zones, is obtained through magnetic resonance imaging (MRI). The infarct region is composed of ischemic myocytes and non-conducting cells (fibrosis, for instance). Electrophysiology is captured using an established cardiac myocyte model of the human ventricle modified to describe ischemia. The simulation results clearly reveal that ectopic beats emerge from micro-reentries that are sustained by the heterogeneous structure of the infarct regions. Because microscopic information about the heterogeneous structure of the infarct regions is not available, Monte-Carlo simulations are used to identify the probabilities of an infarct region to behave as an ectopic focus for different levels of ischemia and different percentages of non-conducting cells. From the proposed model, it is observed that ectopic beats are generated when a percentage of non-conducting cells is near a topological metric known as the percolation threshold. Although the mechanism for micro-reentries was proposed half a century ago to be a source of ectopic beats or premature ventricular contractions during myocardial infarction, the present study is the first to reproduce this mechanism in-silico using patient-specific data.