  We propose HookNet, a semantic segmentation model for histopathology
whole-slide images, which combines context and details via multiple branches of
encoder-decoder convolutional neural networks. Concentricpatches at multiple
resolutions with different fields of view are used to feed different branches
of HookNet, and intermediate representations are combined via a hooking
mechanism. We describe a framework to design and train HookNet for achieving
high-resolution semantic segmentation and introduce constraints to guarantee
pixel-wise alignment in feature maps during hooking. We show the advantages of
using HookNet in two histopathology image segmentation tasks where tissue type
prediction accuracy strongly depends on contextual information, namely (1)
multi-class tissue segmentation in breast cancer and, (2) segmentation of
tertiary lymphoid structures and germinal centers in lung cancer. Weshow the
superiority of HookNet when compared with single-resolution U-Net models
working at different resolutions as well as with a recently published
multi-resolution model for histopathology image segmentation
