Understanding Automatic Pneumonia Classification Using Chest X-Ray Images

Pneumonia has been recognized as a common and potentially lethal condition for nearly two centuries. The COVID-19 disease caused by the SARS-CoV-2 virus first appeared in Wuhan, China, and is considered a serious disease due to its high permeability, and contagiousness. Patients with COVID-19 may suffer from cough, fever, tiredness, dyspnea, and other signs and symptoms similar to those of tuberculosis (TB) and other respiratory infections disease. The similarity of COVID-19 disease with other lung infections, along with its high spreading rate, makes the diagnosis difficult. Solutions based on machine learning techniques achieved relevant results in identifying the correct disease and providing early diagnosis, and can hence provide significant clinical decision support; however, such approaches suffer from the lack of proper means for interpreting the choices made by the models, especially in case of deep learning ones. With the aim to improve interpretability and explainability in the process of making qualified decisions, we designed a system that allows a partial opening of this black box by means of proper investigations on the rationale behind the decisions. We tested our approach over artificial neural networks trained for multiple classifications based on Chest X-ray images; our tool analyzed the internal processes performed by the networks during the classification tasks to identify the most important elements involved in the training process that influence the network’s decisions. We report the results of an experimental analysis aimed at assessing the viability of the proposed approach.