An empirical study of using radiology reports and images to improve ICU-mortality prediction.

The predictive Intensive Care Unit (ICU) scoring system plays an important role in ICU management for its capability of predicting important outcomes, especially mortality. There are many scoring systems that have been developed and used in the ICU. These scoring systems are primarily based on the structured clinical data contained in the electronic health record (EHR), which may suffer the loss of the important clinical information contained in the narratives and images. In this work, we build a deep learning based survival prediction model with multi-modality data to predict ICU-mortality. Four sets of features are investigated: (1) physiological measurements of Simplified Acute Physiology Score (SAPS) II, (2) common thorax diseases pre-defined by radiologists, (3) BERT-based text representations, and (4) chest X-ray image features. We use the Medical Information Mart for Intensive Care IV (MIMIC-IV) dataset to evaluate the proposed model. Our model achieves the average C-index of 0.7847 (95% confidence interval, 0.7625-0.8068), which substantially exceeds that of the baseline with SAPS-II features (0.7477 (0.7238-0.7716)). Ablation studies further demonstrate the contributions of pre-defined labels (2.12%), text features (2.68%), and image features (2.96%). Our model achieves a higher average C-index than the traditional machine learning methods under the same feature fusion setting, which suggests that the deep learning methods can outperform the traditional machine learning methods in ICU-mortality prediction. These results highlight the potential of deep learning models with multimodal information to enhance ICU-mortality prediction. We make our work publicly available at https://github.com/bionlplab/mimic-icu-mortality.