Generating a normalized geometric liver model using warping.

Rationale And Objectives: Automated liver surface determination in abdominal computed tomography scans, currently difficult to achieve, is of interest to determine liver location and size for various medical applications, including radiation therapy treatment planning, surgical planning, and oncologic monitoring. The authors propose to facilitate automation by the addition of a priori shape information in the form of a liver model.

Methods: The normalized geometric liver model is generated by averaging outlines from a set of normal liver studies previously registered using thin-plate spline warping. The model consists of an averaged liver surface, a set of anatomic landmarks, and a deformation function.

Results: A liver model is presented and its ability to represent normal liver shapes is demonstrated.

Conclusions: Liver surface warping provides a means of data normalization for model construction and a means of model deformation for representation of liver organ shapes.