Fredrik Isaksson: Quantifying effects of deformable CT-MR registration

Abstract: Rigid image registration is an important part of many medical applications. In order to make correct decisions from the registration process the uncertainty of the results should be included. In this thesis a framework for estimating and visualising the spatial uncertainty of rigid image registration without groundtruth measurements is presented. The framework uses a deformable registration algorithm to estimate the errors and a groupwise registration for collocating multiple image sets to generate multiple realizations of the error field. A mean and covariance field are then generated which allows a characterization of the error field. The framework is used to evaluate errors in CT-MR registration and a statistically significant bias field is detected using random field theory. It is also established that B-spline registration of CT images to themselves exhibit a bias."