Accuracy assessment of CBCT-based volumetric brain shift field

Abstract

The displacement of the brain parenchyma during open brain surgery, known as ‘brain shift’, affects the applicability of pre-operative planning and affects the outcome of the surgery. In this article we investigated the accuracy of a novel method to intra-operatively determine the brain shift displacement field throughout the whole brain volume. The brain shift displacement was determined by acquiring contrast enhanced cone-beam CT before and during the surgery. The respective datasets were pre-processed, landmark enhanced, and elastically registered to find the displacement field. The accuracy of this method was evaluated by artificially creating post-operative data with a known ground truth deformation. The artificial post-operative data was obtained by applying the deformation field from one patient on the pre-operative data of another patient, which was repeated for three patients. The mean error that was found with this method ranged from 1 to 2 mm, while the standard deviation was about 1 mm.