Smart Paint – A New Interactive Segmentation Method Applied to MR Prostate Segmentation

This paper describes a general method for interactive segmentation, Smart Paint. The user interaction is inspired by the way an airbrush is used, objects are segmented by ”sweeping” with the mouse cursor in the image. The user adds or removes details in 3D by the proposed segmentation tool and the user interface shows the segmentation result in 2D slices through the object. We use the novel method for prostate segmentation in transversal T2-weighted MR images from multiple centers and vendors and with differences in scanning protocol. The method was evaluated on the training set obtained from http: //promise12.grand-challenge.org. In the first round, all 50 volumes were segmented and the mean of Dice’s coefficient was 0.82 with standard deviation 0.09. In a second round, the first 30 volumes were re-segmented by the same user and the result was slightly improved – Dice’s coefficient 0.86 ± 0.05 was obtained. For the training data, the mean time to segment a volume was 3 minutes and 30 seconds. The proposed method is a generic tool for interactive image segmentation and this paper illustrates that it is well-suited for prostate segmentation.