Deep learning survival model predicts outcome after intracerebral hemorrhage from initial CT scan

Abstract

Background: Predicting functional impairment after intracerebral hemorrhage (ICH) provides valuable information for planning of patient care and rehabilitation strategies. Current prognostic tools are limited in making long term predictions and require multiple expert-defined inputs and interpretation that make their clinical implementation challenging. This study aimed to predict long term functional impairment of ICH patients from admission non-contrast CT scans, leveraging deep learning models in a survival analysis framework.

Methods: We used the admission non-contrast CT scans from 882 patients from the Massachusetts General Hospital ICH Study for training, hyperparameter optimization, and model selection, and 146 patients from the Yale New Haven ICH Study for external validation of a deep learning model predicting functional outcome. Disability (modified Rankin scale [mRS] > 2), severe disability (mRS > 4), and dependent living status were assessed via telephone interviews after 6, 12, and 24 months. The prediction methods were evaluated by the c-index and compared with ICH score and FUNC score.

Results: Using non-contrast CT, our deep learning model achieved higher prediction accuracy of post-ICH dependent living, disability, and severe disability by 6, 12, and 24 months (c-index 0.742 [95% CI -0.700 to 0.778], 0.712 [95% CI -0.674 to 0.752], 0.779 [95% CI -0.733 to 0.832] respectively) compared with the ICH score (c-index 0.673 [95% CI -0.662 to 0.688], 0.647 [95% CI -0.637 to 0.661] and 0.697 [95% CI -0.675 to 0.717]) and FUNC score (c-index 0.701 [95% CI- 0.698 to 0.723], 0.668 [95% CI -0.657 to 0.680] and 0.727 [95% CI -0.708 to 0.753]). In the external independent Yale-ICH cohort, similar performance metrics were obtained for disability and severe disability (c-index 0.725 [95% CI -0.673 to 0.781] and 0.747 [95% CI -0.676 to 0.807], respectively). Similar AUC of predicting each outcome at 6 months, 1 and 2 years after ICH was achieved compared with ICH score and FUNC score.

Conclusion: We developed a generalizable deep learning model to predict onset of dependent living and disability after ICH, which could help to guide treatment decisions, advise relatives in the acute setting, optimize rehabilitation strategies, and anticipate long-term care needs.

Keywords: CT; deep learning; intracerebral hemorrhage; survival model.

Graphical abstract

Figure 1.

fICHnet architecture. Arrows indicate computation operations and boxes indicate the intermediate outputs. The dimensions of these outputs are listed in the last row in the format of output height × output width × output channels.

Figure 2.

Patient selection flowchart in the MGH-ICH cohort. Complete brain coverage was defined as CT slices with a thickness of 5mm or lower and covering at least 50mm of the brain along the axial slices.

Figure 3.

Receiver operator characteristics (ROC) curve for prediction models of post-ICH functional outcomes at different time points.

Figure 4.

Saliency maps superimposed on the NCCT scans. Regions with higher saliency values are more heavily weighed by fICHnet in predicting post-ICH outcomes. The slice with the highest saliency values was selected for presentation.