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1.
Artigo em Inglês | MEDLINE | ID: mdl-37709167

RESUMO

OBJECTIVE: Postoperative atrial fibrillation (POAF) is common after cardiac surgery and is often considered to be benign despite recent data suggesting worse outcomes. There are no guidelines for the amount of POAF that triggers anticoagulation or for postoperative surveillance. We examined the rate of POAF, incidence of neurologic events, development of permanent atrial fibrillation, and mortality in patients undergoing isolated mitral valve surgery at a Mitral Foundation reference center. METHODS: This is a retrospective cohort study of 922 adult patients from 2011 to 2022 with no preoperative history of arrhythmias. Multivariable logistic regression was used to identify independent risk factors for the primary outcomes. Kaplan-Meier analysis and Cox proportional-hazards model were used to characterize long-term survival. RESULTS: The incidence of POAF was 39%. Median follow-up was 4.9 months (interquartile range, 1.1-42.6 months). Diabetes (odds ratio [OR], 2.2; 95% CI, 1.2-4.1; P = .01) and increasing age (OR, 1.1; 95% CI, 1.0-1.1; P < .001) were risk factors for POAF, whereas New York Heart Association functional class was not. POAF was a risk factor for the development of permanent atrial fibrillation (OR, 3.2; 95% CI 1.9-5.4; P < .001), which was associated with increased risk of neurologic events (OR, 3.8; 95% CI, 1.5-9.7; P = .004). Ultimately, patients with POAF had worse unadjusted (P < .001) and adjusted long-term mortality (hazard ratio, 1.8; 95% CI, 1.1-3.1; P = .03). CONCLUSIONS: POAF is associated with an increased rate of neurologic events, portends development of permanent atrial fibrillation, and is associated with worse long-term survival. POAF is not benign and carries a long-term mortality implication.

2.
Radiother Oncol ; 183: 109638, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37004837

RESUMO

BACKGROUND AND PURPOSE: Prognosis in locally advanced head and neck cancer (HNC) is currently based on TNM staging system and tumor subsite. However, quantitative imaging features (i.e., radiomic features) from magnetic resonance imaging (MRI) may provide additional prognostic info. The aim of this work is to develop and validate an MRI-based prognostic radiomic signature for locally advanced HNC. MATERIALS AND METHODS: Radiomic features were extracted from T1- and T2-weighted MRI (T1w and T2w) using the segmentation of the primary tumor as mask. In total 1072 features (536 per image type) were extracted for each tumor. A retrospective multi-centric dataset (n = 285) was used for features selection and model training. The selected features were used to fit a Cox proportional hazard regression model for overall survival (OS) that outputs the radiomic signature. The signature was then validated on a prospective multi-centric dataset (n = 234). Prognostic performance for OS and disease-free survival (DFS) was evaluated using C-index. Additional prognostic value of the radiomic signature was explored. RESULTS: The radiomic signature had C-index = 0.64 for OS and C-index = 0.60 for DFS in the validation set. The addition of the radiomic signature to other clinical features (TNM staging and tumor subsite) increased prognostic ability for both OS (HPV- C-index 0.63 to 0.65; HPV+ C-index 0.75 to 0.80) and DFS (HPV- C-index 0.58 to 0.61; HPV+ C-index 0.64 to 0.65). CONCLUSION: An MRI-based prognostic radiomic signature was developed and prospectively validated. Such signature can successfully integrate clinical factors in both HPV+ and HPV- tumors.


Assuntos
Neoplasias de Cabeça e Pescoço , Infecções por Papillomavirus , Humanos , Prognóstico , Estudos Retrospectivos , Estudos Prospectivos , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos
3.
Rev. bras. entomol ; 67(3): e20230041, 2023. graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1515040

RESUMO

ABSTRACT The Brazilian fauna of Meloidae is poorly studied, even though it includes more than 160 species. In this paper, we aimed at widening the knowledge on four species of blister beetles from this country. Specifically, we defined the uncertain range of Tetraonyx angulicollis, as extended in south-eastern Brazil rather than in Mexico, and implemented the description of the species with figures. We studied the taxonomy and distribution of three almost unknown species of Nemognatha from Brazil, São Paulo State, providing descriptions and figures of sexual characters and colour variability of N. beauregardi, to which is probably referable as a junior synonym of N. plaumanni, of N. rufoscutellaris and of N. cfr. gounellei. Moreover, we assigned these three species to the subgenus Pauronemognatha, recently recorded from South America.

4.
Front Oncol ; 12: 1016123, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36531029

RESUMO

Objective: The extent of response to neoadjuvant chemotherapy predicts survival in Ewing sarcoma. This study focuses on MRI radiomics of skeletal Ewing sarcoma and aims to investigate feature reproducibility and machine learning prediction of response to neoadjuvant chemotherapy. Materials and methods: This retrospective study included thirty patients with biopsy-proven skeletal Ewing sarcoma, who were treated with neoadjuvant chemotherapy before surgery at two tertiary sarcoma centres. 7 patients were poor responders and 23 were good responders based on pathological assessment of the surgical specimen. On pre-treatment T1-weighted and T2-weighted MRI, 2D and 3D tumour segmentations were manually performed. Features were extracted from original and wavelet-transformed images. Feature reproducibility was assessed through small geometrical transformations of the regions of interest mimicking multiple manual delineations, and intraclass correlation coefficient >0.75 defined feature reproducibility. Feature selection also consisted of collinearity and significance analysis. After class balancing in the training cohort, three machine learning classifiers were trained and tested on unseen data using hold-out cross-validation. Results: 1303 (77%) 3D and 620 (65%) 2D radiomic features were reproducible. 4 3D and 4 2D features passed feature selection. Logistic regression built upon 3D features achieved the best performance with 85% accuracy (AUC=0.9) in predicting response to neoadjuvant chemotherapy. Conclusion: Compared to 2D approach, 3D MRI radiomics of Ewing sarcoma had superior reproducibility and higher accuracy in predicting response to neoadjuvant chemotherapy, particularly when using logistic regression classifier.

5.
Radiol Med ; 127(5): 518-525, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35320464

RESUMO

PURPOSE: To evaluate stability and machine learning-based classification performance of radiomic features of spine bone tumors using diffusion- and T2-weighted magnetic resonance imaging (MRI). MATERIAL AND METHODS: This retrospective study included 101 patients with histology-proven spine bone tumor (22 benign; 38 primary malignant; 41 metastatic). All tumor volumes were manually segmented on morphologic T2-weighted sequences. The same region of interest (ROI) was used to perform radiomic analysis on ADC map. A total of 1702 radiomic features was considered. Feature stability was assessed through small geometrical transformations of the ROIs mimicking multiple manual delineations. Intraclass correlation coefficient (ICC) quantified feature stability. Feature selection consisted of stability-based (ICC > 0.75) and significance-based selections (ranking features by decreasing Mann-Whitney p-value). Class balancing was performed to oversample the minority (i.e., benign) class. Selected features were used to train and test a support vector machine (SVM) to discriminate benign from malignant spine tumors using tenfold cross-validation. RESULTS: A total of 76.4% radiomic features were stable. The quality metrics for the SVM were evaluated as a function of the number of selected features. The radiomic model with the best performance and the lowest number of features for classifying tumor types included 8 features. The metrics were 78% sensitivity, 68% specificity, 76% accuracy and AUC 0.78. CONCLUSION: SVM classifiers based on radiomic features extracted from T2- and diffusion-weighted imaging with ADC map are promising for classification of spine bone tumors. Radiomic features of spine bone tumors show good reproducibility rates.


Assuntos
Neoplasias Ósseas , Aprendizado de Máquina , Neoplasias Ósseas/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Reprodutibilidade dos Testes , Estudos Retrospectivos
6.
J Imaging ; 8(2)2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-35200748

RESUMO

BACKGROUND: Response to induction chemotherapy (IC) has been predicted in patients with sinonasal cancer using early delta radiomics obtained from T1- and T2-weighted images and apparent diffusion coefficient (ADC) maps, comparing results with early radiological evaluation by RECIST. METHODS: Fifty patients were included in the study. For each image (at baseline and after the first IC cycle), 536 radiomic features were extracted as follows: semi-supervised principal component analysis components, explaining 97% of the variance, were used together with a support vector machine (SVM) to develop a radiomic signature. One signature was developed for each sequence (T1-, T2-weighted and ADC). A multiagent decision-making algorithm was used to merge multiple signatures into one score. RESULTS: The area under the curve (AUC) for mono-modality signatures was 0.79 (CI: 0.65-0.88), 0.76 (CI: 0.62-0.87) and 0.93 (CI: 0.75-1) using T1-, T2-weighted and ADC images, respectively. The fuse signature improved the AUC when an ADC-based signature was added. Radiological prediction using RECIST criteria reached an accuracy of 0.78. CONCLUSIONS: These results suggest the importance of early delta radiomics and of ADC maps to predict the response to IC in sinonasal cancers.

7.
NMR Biomed ; 35(4): e4265, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-32009265

RESUMO

In this paper, several radiomics-based predictive models of response to induction chemotherapy (IC) in sinonasal cancers (SNCs) are built and tested. Models were built as a combination of radiomic features extracted from three types of MRI images: T1-weighted images, T2-weighted images and apparent diffusion coefficient (ADC) maps. Fifty patients (aged 54 ± 12 years, 41 men) were included in this study. Patients were classified according to their response to IC (25 responders and 25 nonresponders). Not all types of images were acquired for all of the patients: 49 had T1-weighted images, 50 had T2-weighted images and 34 had ADC maps. Only in a subset of 33 patients were all three types of image acquired. Eighty-nine radiomic features were extracted from the MRI images. Dimensionality reduction was performed by using principal component analysis (PCA) and by selecting only the three main components. Different algorithms (trees ensemble, K-nearest neighbors, support vector machine, naïve Bayes) were used to classify the patients as either responders or nonresponders. Several radiomic models (either monomodality or multimodality obtained by a combination of T1-weighted, T2-weighted and ADC images) were developed and the performance was assessed through 100 iterations of train and test split. The area under the curve (AUC) of the models ranged from 0.56 to 0.78. Trees ensemble, support vector machine and naïve Bayes performed similarly, but in all cases ADC-based models performed better. Trees ensemble gave the highest AUC (0.78 for the T1-weighted+T2-weighted+ADC model) and was used for further analyses. For trees ensemble, the models based on ADC features performed better than those models that did not use those features (P < 0.02 for one-tail Hanley test, AUC range 0.68-0.78 vs 0.56-0.69) except the T1-weighted+ADC model (AUC 0.71 vs 0.69, nonsignificant differences). The results suggest the relevance of ADC-based radiomics for prediction of response to IC in SNCs.


Assuntos
Quimioterapia de Indução , Neoplasias , Adulto , Idoso , Teorema de Bayes , Imagem de Difusão por Ressonância Magnética , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
8.
Diagnostics (Basel) ; 11(6)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071518

RESUMO

Baseline clinical prognostic factors for recurrent and/or metastatic (RM) head and neck squamous cell carcinoma (HNSCC) treated with immunotherapy are lacking. CT-based radiomics may provide additional prognostic information. A total of 85 patients with RM-HNSCC were enrolled for this study. For each tumor, radiomic features were extracted from the segmentation of the largest tumor mass. A pipeline including different feature selection steps was used to train a radiomic signature prognostic for 10-month overall survival (OS). Features were selected based on their stability to geometrical transformation of the segmentation (intraclass correlation coefficient, ICC > 0.75) and their predictive power (area under the curve, AUC > 0.7). The predictive model was developed using the least absolute shrinkage and selection operator (LASSO) in combination with the support vector machine. The model was developed based on the first 68 enrolled patients and tested on the last 17 patients. Classification performance of the radiomic risk was evaluated accuracy and the AUC. The same metrics were computed for some baseline predictors used in clinical practice (volume of largest lesion, total tumor volume, number of tumor lesions, number of affected organs, performance status). The AUC in the test set was 0.67, while accuracy was 0.82. The performance of the radiomic score was higher than the one obtainable with the clinical variables (largest lesion volume: accuracy 0.59, AUC = 0.55; number of tumoral lesions: accuracy 0.71, AUC 0.36; number of affected organs: accuracy 0.47; AUC 0.42; total tumor volume: accuracy 0.59, AUC 0.53; performance status: accuracy 0.41, AUC = 0.47). Radiomics may provide additional baseline prognostic value compared to the variables used in clinical practice.

9.
Acta Oncol ; 60(9): 1192-1200, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34038324

RESUMO

OBJECTIVES: To identify and validate baseline magnetic resonance imaging (b-MRI) radiomic features (RFs) as predictors of disease outcomes in effectively cured head and neck squamous cell carcinoma (HNSCC) patients. MATERIALS AND METHODS: Training set (TS) and validation set (VS) were retrieved from preexisting datasets (HETeCo and BD2Decide trials, respectively). Only patients with both pre- and post-contrast enhancement T1 and T2-weighted b-MRI and at least 2 years of follow-up (FUP) were selected. The combination of the best extracted RFs was used to classify low risk (LR) vs. high risk (HR) of disease recurrence. Sensitivity, specificity, and area under the curve (AUC) of the radiomic model were computed on both TS and VS. Overall survival (OS) and 5-year disease-free survival (DFS) Kaplan-Meier (KM) curves were compared for LR vs. HR. The radiomic-based risk class was used in a multivariate Cox model, including well-established clinical prognostic factors (TNM, sub-site, human papillomavirus [HPV]). RESULTS: In total, 57 patients of TS and 137 of VS were included. Three RFs were selected for the signature. Sensitivity of recurrence risk classifier was 0.82 and 0.77, specificity 0.78 and 0.81, AUC 0.83 and 0.78 for TS and VS, respectively. VS KM curves for LR vs. HR groups significantly differed both for 5-year DFS (p<.0001) and OS (p=.0004). A combined model of RFs plus TNM improved prognostic performance as compared to TNM alone, both for VS 5-year DFS (C-index: 0.76 vs. 0.60) and OS (C-index: 0.74 vs. 0.64). CONCLUSIONS: Radiomics of b-MRI can help to predict recurrence and survival outcomes in HNSCC.


Assuntos
Neoplasias de Cabeça e Pescoço , Recidiva Local de Neoplasia , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Recidiva Local de Neoplasia/diagnóstico por imagem , Prognóstico , Estudos Retrospectivos , Carcinoma de Células Escamosas de Cabeça e Pescoço/diagnóstico por imagem
10.
PLoS One ; 16(2): e0247748, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33635906

RESUMO

PURPOSE: To study a robust and reproducible procedure to investigate a relation between focal brain radiotherapy (RT) low doses, neurocognitive impairment and late White Matter and Gray Matter alterations, as shown by Diffusion Tensor Imaging (DTI), in children. METHODS AND MATERIALS: Forty-five patients (23 males and 22 females, median age at RT 6.2 years, median age at evaluations 11.1 years) who had received focal RT for brain tumors were recruited for DTI exams and neurocognitive tests. Patients' brains were parceled in 116 regions of interest (ROIs) using an available segmented atlas. After the development of an ad hoc, home-made, multimodal and highly deformable registration framework, we collected mean RT doses and DTI metrics values for each ROI. The pattern of association between cognitive scores or domains and dose or DTI values was assessed in each ROI through both considering and excluding ROIs with mean doses higher than 75% of the prescription. Subsequently, a preliminary threshold value of dose discriminating patients with and without neurocognitive impairment was selected for the most relevant associations. RESULTS: The workflow allowed us to identify 10 ROIs where RT dose and DTI metrics were significantly associated with cognitive tests results (p<0.05). In 5/10 ROIs, RT dose and cognitive tests were associated with p<0.01 and preliminary RT threshold dose values, implying a possible cognitive or neuropsychological damage, were calculated. The analysis of domains showed that the most involved one was the "school-related activities". CONCLUSION: This analysis, despite being conducted on a retrospective cohort of children, shows that the identification of critical brain structures and respective radiation dose thresholds is achievable by combining, with appropriate methodological tools, the large amount of data arising from different sources. This supported the design of a prospective study to gain stronger evidence.


Assuntos
Anormalidades Induzidas por Radiação/diagnóstico por imagem , Neoplasias Encefálicas/radioterapia , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/efeitos da radiação , Substância Branca/diagnóstico por imagem , Substância Branca/efeitos da radiação , Criança , Imagem de Tensor de Difusão/métodos , Feminino , Seguimentos , Humanos , Masculino , Testes de Estado Mental e Demência , Transtornos Neurocognitivos , Estudos Retrospectivos
11.
Head Neck ; 43(2): 601-612, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33107152

RESUMO

BACKGROUND: Despite advances in treatments, 30% to 50% of stage III-IV head and neck squamous cell carcinoma (HNSCC) patients relapse within 2 years after treatment. The Big Data to Decide (BD2Decide) project aimed to build a database for prognostic prediction modeling. METHODS: Stage III-IV HNSCC patients with locoregionally advanced HNSCC treated with curative intent (1537) were included. Whole transcriptomics and radiomics analyses were performed using pretreatment tumor samples and computed tomography/magnetic resonance imaging scans, respectively. RESULTS: The entire cohort was composed of 71% male (1097)and 29% female (440): oral cavity (429, 28%), oropharynx (624, 41%), larynx (314, 20%), and hypopharynx (170, 11%); median follow-up 50.5 months. Transcriptomics and imaging data were available for 1284 (83%) and 1239 (80%) cases, respectively; 1047 (68%) patients shared both. CONCLUSIONS: This annotated database represents the HNSCC largest available repository and will enable to develop/validate a decision support system integrating multiscale data to explore through classical and machine learning models their prognostic role.


Assuntos
Big Data , Neoplasias de Cabeça e Pescoço , Feminino , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Masculino , Recidiva Local de Neoplasia/genética , Prognóstico , Carcinoma de Células Escamosas de Cabeça e Pescoço/diagnóstico por imagem , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética
12.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 1152-1155, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018191

RESUMO

The purpose of this study was to establish a methodology and technology for the development of an MRI-based radiomic signature for prognosis of overall survival (OS) in nasopharyngeal cancer from non-endemic areas. The signature was trained using 1072 features extracted from the main tumor in T1-weighted and T2-weighted images of 142 patients. A model with 2 radiomic features was obtained (RAD model). Tumor volume and a signature obtained by training the model on permuted survival data (RADperm model) were used as a reference. A 10-fold cross-validation was used to validate the signature. Harrel's C-index was used as performance metric. A statistical comparison of the RAD, RADperm and volume was performed using Wilcoxon signed rank tests. The C-index for the RAD model was higher compared to the one of the RADperm model (0.69±0.08 vs 0.47±0.05), which ensures absence of overfitting. Also, the signature obtained with the RAD model had an improved C-index compared to tumor volume alone (0.69±0.08 vs 0.65±0.06), suggesting that the radiomic signature provides additional prognostic information.


Assuntos
Neoplasias de Cabeça e Pescoço , Neoplasias Nasofaríngeas , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Prognóstico , Estudos Retrospectivos
13.
Cancers (Basel) ; 12(10)2020 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-33066161

RESUMO

Advanced stage nasopharyngeal cancer (NPC) shows highly variable treatment outcomes, suggesting the need for independent prognostic factors. This study aims at developing a magnetic resonance imaging (MRI)-based radiomic signature as a prognostic marker for different clinical endpoints in NPC patients from non-endemic areas. A total 136 patients with advanced NPC and available MRI imaging (T1-weighted and T2-weighted) were selected. For each patient, 2144 radiomic features were extracted from the main tumor and largest lymph node. A multivariate Cox regression model was trained on a subset of features to obtain a radiomic signature for overall survival (OS), which was also applied for the prognosis of other clinical endpoints. Validation was performed using 10-fold cross-validation. The added prognostic value of the radiomic features to clinical features and volume was also evaluated. The radiomics-based signature had good prognostic power for OS and loco-regional recurrence-free survival (LRFS), with C-index of 0.68 and 0.72, respectively. In all the cases, the addition of radiomics to clinical features improved the prognostic performance. Radiomic features can provide independent prognostic information in NPC patients from non-endemic areas.

14.
Med Biol Eng Comput ; 58(4): 843-855, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32048135

RESUMO

Survival of pediatric patients with brain tumor has increased over the past 20 years, and increasing evidence of iatrogenic toxicities has been reported. In follow-ups, images are acquired at different time points where substantial changes of brain morphology occur, due to childhood physiological development and treatment effects. To address the image registration complexity, we propose two multi-metric approaches (Mplus, Mdot), combining mutual information (MI) and normalized gradient field filter (NGF). The registration performance of the proposed metrics was assessed on a simulated dataset (Brainweb) and compared with those obtained by MI and NGF separately, using mean magnitude and mean angular errors. The most promising metric (Mplus) was then selected and tested on a retrospective dataset comprising 45 pediatric patients who underwent focal radiotherapy for brain cancer. The quality of the realignment was scored by a radiation oncologist using a perceived misalignment metric (PM). All patients but one were assessed as PM ≤ 2 (good alignment), but the remaining one, severely affected by hydrocephalus and pneumocephalus at the first MRI acquisition, scored PM = 5 (unacceptable). These preliminary findings suggest that Mplus might improve the registration accuracy in complex applications such as pediatric oncology, when data are acquired throughout the years of follow-up, and is worth investigating. Graphical abstract Graphical abstract showing the clinical workflow of the overall registration procedure including the three rigid steps, the fourth deformable step, the reference MRI and the registered MRI as well as the contoured ROIs. The registration performance is assessed by means of the Perceived Misalignment score (PM).


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Neoplasias Encefálicas/radioterapia , Criança , Pré-Escolar , Humanos , Estudos Retrospectivos
15.
Mol Phylogenet Evol ; 144: 106706, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31830551

RESUMO

Hycleus is a hyper-diverse genus of blister beetles including ~500 species widely distributed in the Old World, currently divided into three "sections" and into 45 "phenetic" species groups according to morphological characters. Recently the monophyly of Hycleus was questioned pointing out its paraphyly with respect to the genera Ceroctis and Paractenodia. In this study, we built a time-calibrated phylogenetic tree based on DNA sequence data from mitochondrial and nuclear genes obtained from 125 species, to understand the phylogenetic relationships among the species of this genus, to infer the biogeographic processes behind their diversification, and to assess their taxonomy and classification. Our results identified four main lineages one of which included the species belonging to Ceroctis and Paractenodia; therefore, both taxa are now referred to Hycleus as new synonyms. The three described sections of Hycleus resulted polyphyletic and are rejected, whereas several species groups represented well supported clades. Hycleus likely originated in Africa during the Early Miocene (~20 Mya), and subsequently spread in Europe and western Asia. Later, in the Late Miocene (~6 Mya) a Saharo-Sindian group branched off from the Palaearctic lineage, whereas the Oriental Region was colonized following a dispersal event through the Arabian Peninsula from the Afrotropical Region (~5 Mya).


Assuntos
Besouros/classificação , Besouros/genética , Variação Genética , África , Animais , Arábia , Ásia Ocidental , Europa (Continente) , Filogenia , Filogeografia , Análise de Sequência de DNA
16.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 782-785, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30440511

RESUMO

The purpose of this study is to identify a set of radiomic features extracted from apparent diffusion coefficient (ADC) maps, obtained using baseline diffusion weighted magnetic resonance imaging (DW-MRI), which are able to predict the outcome of induction chemotherapy (IC) in sinonasal cancers. Such prediction could help the clinician defining the better treatment for a particular patient. Eighty-eight radiomic features were extracted from the ADC maps of 15 patients that underwent IC. A preliminary filtering of the features was made by assessing their stability to geometrical transformations of the region of interest (ROI). Mann-Whitney tests corrected for control of false discoveries were performed to identify the features that could discriminate between responsive and nonresponsive patients (4 and 11 respectively). Twenty features were found to be able to discriminate the two groups and they can potentially be used for prediction of response to treatment.


Assuntos
Imagem de Difusão por Ressonância Magnética , Neoplasias , Humanos , Quimioterapia de Indução , Neoplasias/tratamento farmacológico
17.
J Digit Imaging ; 31(6): 879-894, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29725965

RESUMO

The objectives of the study are to develop a new way to assess stability and discrimination capacity of radiomic features without the need of test-retest or multiple delineations and to use information obtained to perform a preliminary feature selection. Apparent diffusion coefficient (ADC) maps were computed from diffusion-weighted magnetic resonance images (DW-MRI) of two groups of patients: 18 with soft tissue sarcomas (STS) and 18 with oropharyngeal cancers (OPC). Sixty-nine radiomic features were computed, using three different histogram discretizations (16, 32, and 64 bins). Geometrical transformations (translations) of increasing entity were applied to the regions of interest (ROIs), and the intra-class correlation coefficient (ICC) was used to compare the features computed on the original and modified ROIs. The distribution of ICC values for minimal and maximal entity translations (ICC10 and ICC100, respectively) was used to adjust thresholds of ICC (ICCmin and ICCmax) used to discriminate between good, unstable (ICC10 < ICCmin), and non-discriminative features (ICC100 > ICCmax). Fifty-four and 59 radiomic features passed the stability-based selection for all the three histogram discretizations for the OPC and STS datasets, respectively. The excluded features were similar across the different histogram discretizations (Jaccard's index 0.77 ± 0.13 and 0.9 ± 0.1 for OPC and STS, respectively) but different between datasets (Jaccard's index 0.19 ± 0.02). The results suggest that the observed radiomic features are mainly stable and discriminative, but the stability depends on the region of the body under observation. The method provides a way to assess stability without the need of test-retest or multiple delineations.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Interpretação de Imagem Assistida por Computador/métodos , Neoplasias Orofaríngeas/diagnóstico por imagem , Sarcoma/diagnóstico por imagem , Bases de Dados Factuais , Humanos , Estudos Retrospectivos
18.
Annu Int Conf IEEE Eng Med Biol Soc ; 2017: 612-615, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29059947

RESUMO

Radiomics extracts a large number of features from medical images to perform a quantitative characterization. Aim of this study was to assess radiomic features stability and relevance. Apparent diffusion coefficient (ADC) maps were computed from diffusion-weighted magnetic resonance images (DW-MRI) of 18 patients diagnosed with soft-tissue sarcomas (STSs). Thirty-seven intensity-based features were computed on the regions of interest (ROIs). First, ROIs of the images were subjected to translations and rotations in specific ranges. The 37 features computed on the original and transformed ROIs were compared in terms of percentage of variations. The intra-class correlation coefficient (ICC) was computed. To be accepted, a feature should satisfy the following conditions: the ICC after a minimum entity transformation is > 0.6 and the ICC after a maximum entity translation is <; 0.4. In total, 31 features out of 37 were accepted by the algorithm. This stability analysis can be used as a first step in the features selection process.


Assuntos
Sarcoma , Difusão , Imagem de Difusão por Ressonância Magnética , Humanos , Espectroscopia de Ressonância Magnética
19.
Med Eng Phys ; 47: 105-116, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28711588

RESUMO

The clinical challenge of percutaneous coronary interventions (PCI) is highly dependent on the recognition of the coronary anatomy of each individual. The classic imaging modality used for PCI is angiography, but advanced imaging techniques that are routinely performed during PCI, like optical coherence tomography (OCT), may provide detailed knowledge of the pre-intervention vessel anatomy as well as the post-procedural assessment of the specific stent-to-vessel interactions. Computational fluid dynamics (CFD) is an emerging investigational tool in the setting of optimization of PCI results. In this study, an OCT-based reconstruction method was developed for the execution of CFD simulations of patient-specific coronary artery models which include the actual geometry of the implanted stent. The method was applied to a rigid phantom resembling a stented segment of the left anterior descending coronary artery. The segmentation algorithm was validated against manual segmentation. A strong correlation was found between automatic and manual segmentation of lumen in terms of area values. Similarity indices resulted >96% for the lumen segmentation and >77% for the stent strut segmentation. The 3D reconstruction achieved for the stented phantom was also assessed with the geometry provided by X-ray computed micro tomography scan, used as ground truth, and showed the incidence of distortion from catheter-based imaging techniques. The 3D reconstruction was successfully used to perform CFD analyses, demonstrating a great potential for patient-specific investigations. In conclusion, OCT may represent a reliable source for patient-specific CFD analyses which may be optimized using dedicated automatic segmentation algorithms.


Assuntos
Circulação Coronária , Vasos Coronários/fisiopatologia , Vasos Coronários/cirurgia , Modelos Cardiovasculares , Modelagem Computacional Específica para o Paciente , Stents , Tomografia de Coerência Óptica/métodos , Velocidade do Fluxo Sanguíneo , Prótese Vascular , Simulação por Computador , Vasos Coronários/patologia , Humanos , Hidrodinâmica , Interpretação de Imagem Assistida por Computador/métodos , Reconhecimento Automatizado de Padrão/métodos , Imagens de Fantasmas , Cirurgia Assistida por Computador/métodos , Tomografia de Coerência Óptica/instrumentação , Resultado do Tratamento
20.
Biodivers Data J ; (3): e4750, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25892924

RESUMO

Fauna Europaea provides a public web-service with an index of scientific names (including synonyms) of all living European land and freshwater animals, their geographical distribution at country level (up to the Urals, excluding the Caucasus region), and some additional information. The Fauna Europaea project covers about 230,000 taxonomic names, including 130,000 accepted species and 14,000 accepted subspecies, which is much more than the originally projected number of 100,000 species. This represents a huge effort by more than 400 contributing specialists throughout Europe and is a unique (standard) reference suitable for many users in science, government, industry, nature conservation and education. Coleoptera represent a huge assemblage of holometabolous insects, including as a whole more than 200 recognized families and some 400,000 described species worldwide. Basic information is summarized on their biology, ecology, economic relevance, and estimated number of undescribed species worldwide. Little less than 30,000 species are listed from Europe. The Coleoptera 2 section of the Fauna Europaea database (Archostemata, Myxophaga, Adephaga and Polyphaga excl. the series Elateriformia, Scarabaeiformia, Staphyliniformia and the superfamily Curculionoidea) encompasses 80 families (according to the previously accepted family-level systematic framework) and approximately 13,000 species. Tabulations included a complete list of the families dealt with, the number of species in each, the names of all involved specialists, and, when possible, an estimate of the gaps in terms of total number of species at an European level. A list of some recent useful references is appended. Most families included in the Coleoptera 2 Section have been updated in the most recent release of the Fauna Europaea index, or are ready to be updated as soon as the FaEu data management environment completes its migration from Zoological Museum Amsterdam to Berlin Museum für Naturkunde.

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