Method for generating unfolded views of organ and its comparison with virtual endoscopy based on undisplayed region rate

This paper describes a method for generating an unfolded view of organs based on elastic deformation. When we observe the inside of an organ that has a large cavity with a virtual endoscopy system, the viewpoint and the view direction need to be changed many times. Unfolded views can visualize the entire organ wall at a glance and are very useful for diagnosis. The unfolding process requires creating a model that approximates the shape of the target organ. The approximated shape is generated from the outer wall of the organ by extracting the organ wall. The user interactively specifies a cutting line on the approximated shape. The stretching is performed by adding forces and calculating the elastic deformation. The volumetric image where the target organ is unfolded is reconstructed from the original image by using the relation between the approximated and the stretched shapes. We applied the proposed method to six 3-D abdominal CT images. The experimental results showed that the method generates adequate unfolded views of the target organs.