Enhanced tuberculosis detection using Vision Transformers and explainable AI with a Grad-CAM approach on chest X-rays

Abstract

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a leading global health challenge, especially in low-resource settings. Accurate diagnosis from chest X-rays is critical yet challenging due to subtle manifestations of TB, particularly in its early stages. Traditional computational methods, primarily using basic convolutional neural networks (CNNs), often require extensive pre-processing and struggle with generalizability across diverse clinical environments. This study introduces a novel Vision Transformer (ViT) model augmented with Gradient-weighted Class Activation Mapping (Grad-CAM) to enhance both diagnostic accuracy and interpretability. The ViT model utilizes self-attention mechanisms to extract long-range dependencies and complex patterns directly from the raw pixel information, whereas Grad-CAM offers visual explanations of model decisions about highlighting significant regions in the X-rays. The model contains a Conv2D stem for initial feature extraction, followed by many transformer encoder blocks, thereby significantly boosting its ability to learn discriminative features without any pre-processing. Performance testing on a validation set had an accuracy of 0.97, recall of 0.99, and F1-score of 0.98 for TB patients. On the test set, the model has accuracy of 0.98, recall of 0.97, and F1-score of 0.98, which is better than existing methods. The addition of Grad-CAM visuals not only improves the transparency of the model but also assists radiologists in assessing and verifying AI-driven diagnoses. These results demonstrate the model's higher diagnostic precision and potential for clinical application in real-world settings, providing a massive improvement in the automated detection of TB.