The aim of this work is to propose an adaptation of optimal path based interactive tools for image segmentation (related to Live-Wire [12] and Intelligent Scissors [18] approaches). We efficiently use both discrete [10] and continuous [6] path search approaches. The segmentation relies on the notion of energy function and we introduce the possibility of complete on-the-fly adaptation of each individual energy term, as well as of their relative weights. Non-specialist users have then a full control of the drawing process which automatically selects the most relevant set of features to steer the path extraction. Tests have been performed on a large variety of medical images.