On the Robustness of Pretraining and Self-Supervision for a Deep Learning-based Analysis of Diabetic Retinopathy

TL;DR

This paper evaluates how different pretraining methods, especially self-supervised contrastive learning, affect the performance, interpretability, and robustness of deep neural networks in diabetic retinopathy classification, highlighting the benefits of ImageNet pretraining.

Contribution

It provides a comprehensive analysis of pretraining strategies, including self-supervised methods, on medical image classification, emphasizing their impact on robustness and interpretability.

Findings

ImageNet pretraining improves performance and robustness.

Self-supervised models outperform supervised models in several metrics.

Pretraining reduces overfitting and enhances detection of minute lesions.

Abstract

There is an increasing number of medical use-cases where classification algorithms based on deep neural networks reach performance levels that are competitive with human medical experts. To alleviate the challenges of small dataset sizes, these systems often rely on pretraining. In this work, we aim to assess the broader implications of these approaches. For diabetic retinopathy grading as exemplary use case, we compare the impact of different training procedures including recently established self-supervised pretraining methods based on contrastive learning. To this end, we investigate different aspects such as quantitative performance, statistics of the learned feature representations, interpretability and robustness to image distortions. Our results indicate that models initialized from ImageNet pretraining report a significant increase in performance, generalization and robustness to image distortions. In particular, self-supervised models show further benefits to supervised models. Self-supervised models with initialization from ImageNet pretraining not only report higher performance, they also reduce overfitting to large lesions along with improvements in taking into account minute lesions indicative of the progression of the disease. Understanding the effects of pretraining in a broader sense that goes beyond simple performance comparisons is of crucial importance for the broader medical imaging community beyond the use-case considered in this work.