11 research outputs found
An Explainable AI System for Automated COVID-19 Assessment and Lesion Categorization from CT-scans
COVID-19 infection caused by SARS-CoV-2 pathogen is a catastrophic pandemic
outbreak all over the world with exponential increasing of confirmed cases and,
unfortunately, deaths. In this work we propose an AI-powered pipeline, based on
the deep-learning paradigm, for automated COVID-19 detection and lesion
categorization from CT scans. We first propose a new segmentation module aimed
at identifying automatically lung parenchyma and lobes. Next, we combined such
segmentation network with classification networks for COVID-19 identification
and lesion categorization. We compare the obtained classification results with
those obtained by three expert radiologists on a dataset consisting of 162 CT
scans. Results showed a sensitivity of 90\% and a specificity of 93.5% for
COVID-19 detection, outperforming those yielded by the expert radiologists, and
an average lesion categorization accuracy of over 84%. Results also show that a
significant role is played by prior lung and lobe segmentation that allowed us
to enhance performance by over 20 percent points. The interpretation of the
trained AI models, moreover, reveals that the most significant areas for
supporting the decision on COVID-19 identification are consistent with the
lesions clinically associated to the virus, i.e., crazy paving, consolidation
and ground glass. This means that the artificial models are able to
discriminate a positive patient from a negative one (both controls and patients
with interstitial pneumonia tested negative to COVID) by evaluating the
presence of those lesions into CT scans. Finally, the AI models are integrated
into a user-friendly GUI to support AI explainability for radiologists, which
is publicly available at http://perceivelab.com/covid-ai
Brain2Image: Converting Brain Signals Into Images
Reading the human mind has been a hot topic in the last decades, and recent research in neuroscience has found evidence on the possibility of decoding, from neuroimaging data, how the human brain works. At the same time, the recent rediscovery of deep learning combined to the large interest of scientific community on generative methods has enabled the generation of realistic images by learning a data distribution from noise. The quality of generated images increases when the input data conveys information on visual content of images. Leveraging on these recent trends, in this paper we present an approach for generating images using visually-evoked brain signals recorded through an electroencephalograph (EEG). More specifically, we recorded EEG data from several subjects while observing images on a screen and tried to regenerate the seen images. To achieve this goal, we developed a deep-learning framework consisting of an LSTM stacked with a generative method, which learns a more compact and noise-free representation of EEG data and employs it to generate the visual stimuli evoking specific brain responses. Our Brain2Image approach was trained and tested using EEG data from six subjects while they were looking at images from 40 ImageNet classes. As generative models, we compared variational autoencoders (VAE) and generative adversarial networks (GAN). The results show that, indeed, our approach is able to generate an image drawn from the same distribution of the shown images. Furthermore, GAN, despite generating less realistic images, show better performance than VAE, especially as concern sharpness. The obtained performance provides useful hints on the fact that EEG contains patterns related to visual content and that such patterns can be used to effectively generate images that are semantically coherent to the evoking visual stimuli