Hydranet: Data Augmentation for Regression Neural Networks

Despite recent efforts, deep learning techniques remain often heavily dependent on a large quantity of labeled data. This problem is even more challenging in medical image analysis where the annotator expertise is often scarce. In this paper we propose a novel data-augmentation method to regularize neural network regressors, learning from a single global label per image. The principle of the method is to create new samples by recombining existing ones. We demonstrate the performance of our algorithm on two tasks: the regression of number of enlarged perivascular spaces in the basal ganglia; and the regression of white matter hyperintensities volume. We show that the proposed method improves the performance even when more basic data augmentation is used. Furthermore we reached an intraclass correlation coefficient between ground truth and network predictions of 0.73 on the first task and 0.86 on the second task, only using between 25 and 30 scans with a single global label per scan for training. To achieve a similar correlation on the first task, state-of-the-art methods needed more than 1000 training scans.