Semantic Segmentation of Colon Glands in Inflammatory Bowel Disease Biopsies.

Robust delineation of tissue components in hematoxylin and eosin (H&E) stained slides is a critical step in quantifying tissue morphology. Fully convolutional neural networks (FCN) are ideally suited for automatic and efficient segmentation of tissue components in H&E slides. However, their performance relies on the network architecture, quality and depth of training. Here we introduce a set of 802 image tiles of colon biopsies from 2 subjects with inflammatory bowel disease (IBD) annotated for glandular epithelium (EP), gland lumen together with goblet cells (LG), and stroma (ST). We either trained the FCN-8s de-novo on our images (DN-FCN-8s) or pre-trained on the ImageNet dataset and fine-tuned on our images (FT-FCN-8s). For comparison, we used the U-Net trained de-novo. The training involved 700/802 images, leaving 102 images as a testing set. Ultimately, each model was validated in an independent digital biopsy slide. We also determined how the number of images used for training affects the performance of the model and observed a plateau in trainability at 700 images. In the testing set, U-Net and FT-FCN-8s achieved accuracies of 92.30% and 92.26% respectively. In the independent biopsy slide, U-Net demonstrated a segmentation accuracy of 88.64%, with F1-scores of 0.74 (EP), 0.92 (LG), and 0.93 (ST). The performance of the FT-FCN-8s was slightly worse, but the model required fewer images to reach a high classification performance. Our data demonstrate that all 3 FCNs are appropriate for segmentation of glands in biopsies from patients with IBD and open the door for quantification of IBD associated pathologies.