Emphysema progression in COPD is highly variable, and there is a lack of prognostic markers that describe the evolution of the disease. We hypothesize that local CT features can provide suitable information for describing the evolution of emphysema. In this work, we propose a deep learning approach to identify “deep local phenotypes” by learning the evolution of lung density and emphysema progression at a timed event using longitudinal autoencoders. Results show that there are local traits, or deep local phenotypes, that can predict the 5-year evolution of the local density patterns. Local features learned from the latent space representation of the emphysema progression seem to provide prognostic markers of progression due to the good performance in identifying regions (32 by 32 pixels) with and without emphysema progression. The model’s performance on our test dataset (n=364 millon of regions from 295 subjects) was AUC5%=0.87, PPV5%=0.57, Sens.5%= 0.55, ACC5%=0.84, Balanced ACC5% = 0.73, F15%=0.56 and K5%=0.46. Prognostication tools to detect local patterns of emphysema progression could be essential to manage COPD patients better, as there are no therapeutic options to reverse (or slow down) emphysema damage. Our approach could also improve the selection of patients in much-needed emphysema treatment trials.
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