Discriminative ensemble learning for few-shot chest x-ray diagnosis.

Few-shot learning is an almost unexplored area in the field of medical image analysis. We propose a method for few-shot diagnosis of diseases and conditions from chest x-rays using discriminative ensemble learning. Our design involves a CNN-based coarse-learner in the first step to learn the general characteristics of chest x-rays. In the second step, we introduce a saliency-based classifier to extract disease-specific salient features from the output of the coarse-learner and classify based on the salient features. We propose a novel discriminative autoencoder ensemble to design the saliency-based classifier. The classification of the diseases is performed based on the salient features. Our algorithm proceeds through meta-training and meta-testing. During the training phase of meta-training, we train the coarse-learner. However, during the training phase of meta-testing, we train only the saliency-based classifier. Thus, our method is first-of-its-kind where the training phase of meta-training and the training phase of meta-testing are architecturally disjoint, making the method modular and easily adaptable to new tasks requiring the training of only the saliency-based classifier. Experiments show as high as ∼19% improvement in terms of F ₁ score compared to the baseline in the diagnosis of chest x-rays from publicly available datasets.
Competing Interests: Declaration of Competing Interest Ronald M. Summers receives royalties from PingAn, iCAD, ScanMed, Translation Holdings and Philips, research support from PingAn, and GPU card donations from NVIDIA.
(Published by Elsevier B.V.)