CNN - ANN with convolutional layers to preserve spatial structure of images to classify images. Great deep learning models for images. Image classification problem to train CNN if the image is a doge or a cat. Seems not important, but we can just replace the images of cats or dogs with medical images to predict the category. Example, predict whether this brain image contains a tumor or not, provided you know the answer through 1000s of observations, train a CNN to predict a new brain image contains a tumor. Deep Learning to accelerate cancer research is an example.