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Publicações

Publicações por CTM

2021

EGFR Assessment in Lung Cancer CT Images: Analysis of Local and Holistic Regions of Interest Using Deep Unsupervised Transfer Learning

Autores
Silva, F; Pereira, T; Morgado, J; Frade, J; Mendes, J; Freitas, C; Negrao, E; De Lima, BF; Da Silva, MC; Madureira, AJ; Ramos, I; Hespanhol, V; Costa, JL; Cunha, A; Oliveira, HP;

Publicação
IEEE ACCESS

Abstract
Statistics have demonstrated that one of the main factors responsible for the high mortality rate related to lung cancer is the late diagnosis. Precision medicine practices have shown advances in the individualized treatment according to the genetic profile of each patient, providing better control on cancer response. Medical imaging offers valuable information with an extensive perspective of the cancer, opening opportunities to explore the imaging manifestations associated with the tumor genotype in a non-invasive way. This work aims to study the relevance of physiological features captured from Computed Tomography images, using three different 2D regions of interest to assess the Epidermal growth factor receptor (EGFR) mutation status: nodule, lung containing the main nodule, and both lungs. A Convolutional Autoencoder was developed for the reconstruction of the input image. Thereafter, the encoder block was used as a feature extractor, stacking a classifier on top to assess the EGFR mutation status. Results showed that extending the analysis beyond the local nodule allowed the capture of more relevant information, suggesting the presence of useful biomarkers using the lung with nodule region of interest, which allowed to obtain the best prediction ability. This comparative study represents an innovative approach for gene mutations status assessment, contributing to the discussion on the extent of pathological phenomena associated with cancer development, and its contribution to more accurate Artificial Intelligence-based solutions, and constituting, to the best of our knowledge, the first deep learning approach that explores a comprehensive analysis for the EGFR mutation status classification.

2021

The Role of Liquid Biopsy in Early Diagnosis of Lung Cancer

Autores
Freitas, C; Sousa, C; Machado, F; Serino, M; Santos, V; Cruz Martins, N; Teixeira, A; Cunha, A; Pereira, T; Oliveira, HP; Costa, JL; Hespanhol, V;

Publicação
FRONTIERS IN ONCOLOGY

Abstract
Liquid biopsy is an emerging technology with a potential role in the screening and early detection of lung cancer. Several liquid biopsy-derived biomarkers have been identified and are currently under ongoing investigation. In this article, we review the available data on the use of circulating biomarkers for the early detection of lung cancer, focusing on the circulating tumor cells, circulating cell-free DNA, circulating micro-RNAs, tumor-derived exosomes, and tumor-educated platelets, providing an overview of future potential applicability in the clinical practice. While several biomarkers have shown exciting results, diagnostic performance and clinical applicability is still limited. The combination of different biomarkers, as well as their combination with other diagnostic tools show great promise, although further research is still required to define and validate the role of liquid biopsies in clinical practice.

2021

Sharing Biomedical Data: Strengthening AI Development in Healthcare

Autores
Pereira, T; Morgado, J; Silva, F; Pelter, MM; Dias, VR; Barros, R; Freitas, C; Negrao, E; de Lima, BF; da Silva, MC; Madureira, AJ; Ramos, I; Hespanhol, V; Costa, JL; Cunha, A; Oliveira, HP;

Publicação
HEALTHCARE

Abstract
Artificial intelligence (AI)-based solutions have revolutionized our world, using extensive datasets and computational resources to create automatic tools for complex tasks that, until now, have been performed by humans. Massive data is a fundamental aspect of the most powerful AI-based algorithms. However, for AI-based healthcare solutions, there are several socioeconomic, technical/infrastructural, and most importantly, legal restrictions, which limit the large collection and access of biomedical data, especially medical imaging. To overcome this important limitation, several alternative solutions have been suggested, including transfer learning approaches, generation of artificial data, adoption of blockchain technology, and creation of an infrastructure composed of anonymous and abstract data. However, none of these strategies is currently able to completely solve this challenge. The need to build large datasets that can be used to develop healthcare solutions deserves special attention from the scientific community, clinicians, all the healthcare players, engineers, ethicists, legislators, and society in general. This paper offers an overview of the data limitation in medical predictive models; its impact on the development of healthcare solutions; benefits and barriers of sharing data; and finally, suggests future directions to overcome data limitations in the medical field and enable AI to enhance healthcare. This perspective is dedicated to the technical requirements of the learning models, and it explains the limitation that comes from poor and small datasets in the medical domain and the technical options that try or can solve the problem related to the lack of massive healthcare data.

2021

Diffuse reflectance and machine learning techniques to differentiate colorectal cancer ex vivo

Autores
Fernandes, L; Carvalho, S; Carneiro, I; Henrique, R; Tuchin, VV; Oliveira, HP; Oliveira, LM;

Publicação
CHAOS

Abstract
In this study, we used machine learning techniques to reconstruct the wavelength dependence of the absorption coefficient of human normal and pathological colorectal mucosa tissues. Using only diffuse reflectance spectra from the ex vivo mucosa tissues as input to algorithms, several approaches were tried before obtaining good matching between the generated absorption coefficients and the ones previously calculated for the mucosa tissues from invasive experimental spectral measurements. Considering the optimized match for the results generated with the multilayer perceptron regression method, we were able to identify differentiated accumulation of lipofuscin in the absorption coefficient spectra of both mucosa tissues as we have done before with the corresponding results calculated directly from invasive measurements. Considering the random forest regressor algorithm, the estimated absorption coefficient spectra almost matched the ones previously calculated. By subtracting the absorption of lipofuscin from these spectra, we obtained similar hemoglobin ratios at 410/550 nm: 18.9-fold/9.3-fold for the healthy mucosa and 46.6-fold/24.2-fold for the pathological mucosa, while from direct calculations, those ratios were 19.7-fold/10.1-fold for the healthy mucosa and 33.1-fold/17.3-fold for the pathological mucosa. The higher values obtained in this study indicate a higher blood content in the pathological samples used to measure the diffuse reflectance spectra. In light of such accuracy and sensibility to the presence of hidden absorbers, with a different accumulation between healthy and pathological tissues, good perspectives become available to develop minimally invasive spectroscopy methods for in vivo early detection and monitoring of colorectal cancer.

2021

Mobile Application for Determining the Concentration of Sulfonamides in Water Using Digital Image Colorimetry

Autores
Reis, P; Carvalho, PH; Peixoto, PS; Segundo, MA; Oliveira, HP;

Publicação
Universal Access in Human-Computer Interaction. Access to Media, Learning and Assistive Environments - 15th International Conference, UAHCI 2021, Held as Part of the 23rd HCI International Conference, HCII 2021, Virtual Event, July 24-29, 2021, Proceedings, Part II

Abstract
Antibiotics are widely applied for the treatment of humans and animals, being the Sulfonamides a special group. The presence of antibiotics in the aquatic environment causes the development antibiotic-resistant bacteria, which is related to the emerging of untreatable infectious diseases. One of the most common methods for determine it consists in high-performance liquid chromatography coupled with mass spectrom-etrym, which is not suitable for an in situ analysis strategy. One important property of sulfonamides is how the compound reacts when added the colorimetric reagent p-dimethylaminocinnamaldehyde, opening the possibility of using colorimetry to measure the concentration. To allow an analysis on the field, the solution needs to be fully mobile and practical. In this context, we recently developed a new screening method based on a computational application running over a picture of the sample; however, despite this approach improving the analysis process when compared to traditional methods, it is still not fully mobile. Smartphones’ computational capabilities are increasing and more powerful than many laptops of older generations. Taking this into account, we developed a mobile analysis application that leverages the computing power and ease of use of a smartphone. The acquired picture will pass through a color correction algorithm to normalize the capture considering the environmental lighting. When the algorithm finishes processing the image, the app will return the estimated concentration of the sample. This approach enables in situ analysis, without requiring an Internet connection nor specific analysis equipment, and the ability to have a rather precise guess of the level of contamination of any water. © Springer Nature Switzerland AG 2021.

2021

The Impact of Interstitial Diseases Patterns on Lung CT Segmentation

Autores
Silva, F; Pereira, T; Morgado, J; Cunha, A; Oliveira, HP;

Publicação
2021 43RD ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE & BIOLOGY SOCIETY (EMBC)

Abstract
Lung segmentation represents a fundamental step in the development of computer-aided decision systems for the investigation of interstitial lung diseases. In a holistic lung analysis, eliminating background areas from Computed Tomography (CT) images is essential to avoid the inclusion of noise information and spend unnecessary computational resources on non-relevant data. However, the major challenge in this segmentation task relies on the ability of the models to deal with imaging manifestations associated with severe disease. Based on U-net, a general biomedical image segmentation architecture, we proposed a light-weight and faster architecture. In this 2D approach, experiments were conducted with a combination of two publicly available databases to improve the heterogeneity of the training data. Results showed that, when compared to the original U-net, the proposed architecture maintained performance levels, achieving 0.894 +/- 0.060, 4.493 +/- 0.633 and 4.457 +/- 0.628 for DSC, HD and HD-95 metrics, respectively, when using all patients from the ILD database for testing only, while allowing a more efficient computational usage. Quantitative and qualitative evaluations on the ability to cope with high-density lung patterns associated with severe disease were conducted, supporting the idea that more representative and diverse data is necessary to build robust and reliable segmentation tools.

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