Virtual lumen insufflation and its application in virtual endoscopy

In this paper, we present a virtual lumen insufflation algorithm and its applications in virtual endoscopy of both pipe-like and non-pipe-like organs. The surface of the lumen outer wall was modeled as isotropic elastic shell elements. The insufflation procedure was simulated by nonlinear finite element method with a constant air pressure exerted on the interior of the shell. The deformation of the inner surface of the lumen was implemented by thin plate spline based kernel transformation. Experiments with both phantom and ten CT data sets were designed to validate the effectiveness of the proposed algorithm. The results show the insufflated lumen is helpful in extending visual field, and extracting exact centerline. Therefore, it will improve visualization quality of virtual straightening, unfolding, and eversion. Compared to the real insufflation, the virtual insufflation can be performed on any kind of surfaces without the closed requirement, and does not change the status of the inner surface. The virtual insufflation will be an effective complement of the real insufflation, especially in some organs, such as blood vessel and bladder, that are unsuitable or hard to insufflate, and some patients who have perforations with increasing risk if performing insufflation.