Classification of malignant and benign lung nodule and prediction of image label class using multi-deep model

Lung cancer has been listed as one of the world’s leading causes of death. Early diagnosis of lung nodules has great significance for the prevention of lung cancer. Despite major improvements in modern diagnosis and treatment, the five-year survival rate is only 18%. Before diagnosis, the classification of lung nodules is one important step, in particular, because automatic classification may help doctors with a valuable opinion. Although deep learning has shown improvement in the image classifications over traditional approaches, which focus on handcraft features, due to a large number of intra-class variational images and the inter-class similar images due to various imaging modalities, it remains challenging to classify lung nodule. In this paper, a multi-deep model (MD model) is proposed for lung nodule classification as well as to predict the image label class. This model is based on three phases that include multi-scale dilated convolutional blocks (MsDc), dual deep convolutional neural networks (DCNN A/B), and multi-task learning component (MTLc). Initially, the multi-scale features are derived through the MsDc process by using different dilated rates to enlarge the respective area. This technique is applied to a pair of images. Such images are accepted by dual DCNNs, and both models can learn mutually from each other in order to enhance the model accuracy. To further improve the performance of the proposed model, the output from both DCNNs split into two portions. The multi-task learning part is used to evaluate whether the input image pair is in the same group or not and also helps to classify them between benign and malignant. Furthermore, it can provide positive guidance if there is an error. Both the intra-class and inter-class (variation and similarity) of a dataset itself increase the efficiency of single DCNN. The effectiveness of mentioned technique is tested empirically by using the popular Lung Image Consortium Database (LIDC) dataset. The results show that the strategy is highly efficient in the form of sensitivity of 90.67%, specificity 90.80%, and accuracy of 90.73%

Attention-Enhanced Cross-Task Network for Analysing Multiple Attributes of Lung Nodules in CT

Accurate characterisation of visual attributes such as spiculation, lobulation, and calcification of lung nodules is critical in cancer management. The characterisation of these attributes is often subjective, which may lead to high inter- and intra-observer variability. Furthermore, lung nodules are often heterogeneous in the cross-sectional image slices of a 3D volume. Current state-of-the-art methods that score multiple attributes rely on deep learning-based multi-task learning (MTL) schemes. These methods, however, extract shared visual features across attributes and then examine each attribute without explicitly leveraging their inherent intercorrelations. Furthermore, current methods either treat each slice with equal importance without considering their relevance or heterogeneity, which limits performance. In this study, we address these challenges with a new convolutional neural network (CNN)-based MTL model that incorporates multiple attention-based learning modules to simultaneously score 9 visual attributes of lung nodules in computed tomography (CT) image volumes. Our model processes entire nodule volumes of arbitrary depth and uses a slice attention module to filter out irrelevant slices. We also introduce cross-attribute and attribute specialisation attention modules that learn an optimal amalgamation of meaningful representations to leverage relationships between attributes. We demonstrate that our model outperforms previous state-of-the-art methods at scoring attributes using the well-known public LIDC-IDRI dataset of pulmonary nodules from over 1,000 patients. Our model also performs competitively when repurposed for benign-malignant classification. Our attention modules also provide easy-to-interpret weights that offer insights into the predictions of the model

Early detection of lung cancer through nodule characterization by Deep Learning

Lung cancer is one of the most frequent cancers in the world with 1.8 million new cases reported in 2012, representing 12.9% of all new cancers worldwide, accounting 1.4 million deaths up to 2008. The importance of early detection and classification of malignant and benign nodules using computed tomography (CT) scans, may facilitate radiologists the tasks of nodule staging assessment and individual therapeutic planning. However, if potential malignant nodules are detected on CT scans, treatments may be less aggressive, not even requiring chemotherapy or radiation therapy after surgery. This Bachelor Thesis focus on the exploration of existing methods and data sets for the automatic classification of lung nodules based on CT images. To this aim, we start by assembling, studying and analyzing some state-of-the-art studies in lung nodule detection, characterization and classification. Furthermore, we report and contextualize state-of-the-art deep learning architectures suited for lung nodule classification. From the public datasets researched, we select a widely used and large data set of lung nodules CT scans, and use it to fine-tune a state-of-theart convolutional neural network. We compare this strategy with training-from-scratch a new shallower neuronal network. Initial evaluation suggests that: (1) Transfer learning is unable to perform correctly due to its inability to adapt between natural images and CT scans domains. (2) Learning from scratch is unable to learn from a small number of samples. However, this first evaluation paves the road towards the design of better classification methods fed by better annotated public-available data sets. In overall, this Project is a mandatory first stage on a hot research topic

Algorithms and Applications of Novel Capsule Networks

Convolutional neural networks, despite their profound impact in countless domains, suffer from significant shortcomings. Linearly-combined scalar feature representations and max pooling operations lead to spatial ambiguities and a lack of robustness to pose variations. Capsule networks can potentially alleviate these issues by storing and routing the pose information of extracted features through their architectures, seeking agreement between the lower-level predictions of higher-level poses at each layer. In this dissertation, we make several key contributions to advance the algorithms of capsule networks in segmentation and classification applications. We create the first ever capsule-based segmentation network in the literature, SegCaps, by introducing a novel locally-constrained dynamic routing algorithm, transformation matrix sharing, the concept of a deconvolutional capsule, extension of the reconstruction regularization to segmentation, and a new encoder-decoder capsule architecture. Following this, we design a capsule-based diagnosis network, D-Caps, which builds off SegCaps and introduces a novel capsule-average pooling technique to handle to larger medical imaging data. Finally, we design an explainable capsule network, X-Caps, which encodes high-level visual object attributes within its capsules by utilizing a multi-task framework and a novel routing sigmoid function which independently routes information from child capsules to parents. Predictions come with human-level explanations, via object attributes, and a confidence score, by training our network directly on the distribution of expert labels, modeling inter-observer agreement and punishing over/under confidence during training. This body of work constitutes significant algorithmic advances to the application of capsule networks, especially in real-world biomedical imaging data

Investigation of Multi-dimensional Tensor Multi-task Learning for Modeling Alzheimer's Disease Progression

Machine learning (ML) techniques for predicting Alzheimer's disease (AD) progression can significantly assist clinicians and researchers in constructing effective AD prevention and treatment strategies. The main constraints on the performance of current ML approaches are prediction accuracy and stability problems in medical small dataset scenarios, monotonic data formats (loss of multi-dimensional knowledge of the data and loss of correlation knowledge between biomarkers) and biomarker interpretability limitations. This thesis investigates how multi-dimensional information and knowledge from biomarker data integrated with multi-task learning approaches to predict AD progression. Firstly, a novel similarity-based quantification approach is proposed with two components: multi-dimensional knowledge vector construction and amalgamated magnitude-direction quantification of brain structural variation, which considers both the magnitude and directional correlations of structural variation between brain biomarkers and encodes the quantified data as a third-order tensor to address the problem of monotonic data form. Secondly, multi-task learning regression algorithms with the ability to integrate multi-dimensional tensor data and mine MRI data for spatio-temporal structural variation information and knowledge were designed and constructed to improve the accuracy, stability and interpretability of AD progression prediction in medical small dataset scenarios. The algorithm consists of three components: supervised symmetric tensor decomposition for extracting biomarker latent factors, tensor multi-task learning regression and algorithmic regularisation terms. The proposed algorithm aims to extract a set of first-order latent factors from the raw data, each represented by its first biomarker, second biomarker and patient sample dimensions, to elucidate potential factors affecting the variability of the data in an interpretable manner and can be utilised as predictor variables for training the prediction model that regards the prediction of each patient as a task, with each task sharing a set of biomarker latent factors obtained from tensor decomposition. Knowledge sharing between tasks improves the generalisation ability of the model and addresses the problem of sparse medical data. The experimental results demonstrate that the proposed approach achieves superior accuracy and stability in predicting various cognitive scores of AD progression compared to single-task learning, benchmarks and state-of-the-art multi-task regression methods. The proposed approach identifies brain structural variations in patients and the important brain biomarker correlations revealed by the experiments can be utilised as potential indicators for AD early identification