A multi-organ point cloud registration algorithm for abdominal CT registration

Samuel JOUTARD, Thomas Pheiffer, Chloe Audigier, Patrick Wohlfahrt, Reuben Dorent, Sebastien Piat, Markus Juergens, Tom Vercauteren, Marc Modat, Tommaso Mansi

Keywords: Registration, Point clouds, CT, Abdominal, Multi-organ, Probabilistic model

TL;DR: We introduce a point cloud registration algorithm to register point clouds representing multiple organs of the abdomen.

Abstract:

Registering CT images of the chest is a crucial step for several tasks such as disease progression tracking or surgical planning. It is also a challenging step because of the heterogeneous content of the human abdomen which implies complex deformations. In this work, we focus on accurately registering a subset of organs of interest. We register organ surface point clouds, as may typically be extracted from an automatic segmentation pipeline, by expanding the Bayesian Coherent Point Drift algorithm (BCPD).
We introduce MO-BCPD, a multi-organ version of the BCPD algorithm which explicitly models three important aspects of this task: organ individual elastic properties, inter-organ motion coherence and segmentation inaccuracy. This model also provides an interpolation framework to estimate the deformation of the entire volume. We demonstrate the efficiency of our method by registering different patients from the LITS challenge dataset. The target registration error on anatomical landmarks is almost twice as small for MO-BCPD compared to standard BCPD while imposing the same constraints on individual organs deformation.

Dataset Code: The code is owned by Siemens Healthineers and cannot be shared. That being said, algorithm 1 contains absolutely all the steps of the method described so MO-BCPD is easily re-implementable by translating algorithm 1 into code. I am also available to provide help for the implementation.