Guidewire tip detection in the percutaneous coronary intervention is important. It assists physicians in navigating and is a prerequisite for clinic applications such as surgical skill
assessment and robot assisted surgery. Nevertheless, accurate detection is not a trivial task due to the noisy background of the 2D X-ray image and the thin, deformable structure of the tip. In this paper, an automatic method based on cascaded convolution neural networks is proposed to segment the tip in the 2D X-ray image. The main contribution of the method is to use a cascade detection-segmentation structure to overcome the noisy background and the large deformation of the tip, achieve robust, high-precision segmentation. On the other hand, sufficient annotated training samples are necessary for convolution neural network models, while pixel-level annotating is tedious and timeconsuming. Accordingly, a novel data augmentation algorithm is introduced to improve the model generalization and performance, reduce the cost of data annotation. Evaluations were conducted on a dataset consisting of 22 different sequences of 2D X-ray images, 15 sequences for training and 7 sequences for evaluation. The proposed approach obtained tip precision of 0.532 pixels, F1 score of 0.939, false tracking rate of 0.800%, and missing tracking rate of 9.900% on the test set. And the running speed is 4-5 frames per second.