Deep Learning in Computed Tomography Pulmonary Angiography Imaging: A Dual-Pronged Approach for Pulmonary Embolism Detection

The increasing reliance on Computed Tomography Pulmonary Angiography for Pulmonary Embolism (PE) diagnosis presents challenges and a pressing need for improved diagnostic solutions. The primary objective of this study is to leverage deep learning techniques to enhance the Computer Assisted Diagnosis of PE. In this study, we propose a classifier-guided detection approach that effectively leverages the classifier's probabilistic inference to direct the detection predictions, marking a novel contribution in the domain of automated PE diagnosis. Our end-to-end classification framework introduces an Attention-Guided Convolutional Neural Network (AG-CNN) that leverages local context by utilizing an attention mechanism. This approach emulates the attention of a human expert by looking at both global appearances and local lesion regions before forming a conclusive decision. The classifier achieves a notable AUROC, sensitivity, specificity and F1-score of 0.927, 0.862, 0.879 and 0.805 respectively on the FUMPE dataset with Inception-v3 backbone architecture. Moreover, AG-CNN outperforms the baseline DenseNet-121 model, achieving an 8.1% AUROC gain. While prior studies have primarily focused on PE detection in main arteries, our utilization of state-of-the-art object detection models and ensembling techniques significantly enhances detection accuracy for small embolisms in the peripheral arteries. Finally, our proposed classifier-guided detection approach further refines the detection metrics contributing new state-of-the-art to the community: mAP$_{50}$, sensitivity and F1-score of 0.846, 0.901 and 0.779 respectively outperforming the former benchmark with a significant 3.7% improvement in mAP$_{50}$. Our research aims to elevate PE patient care by integrating AI solutions into clinical workflows, highlighting the potential of human-AI collaboration in medical diagnostics.