New PhD on "Intra-Operative Non-Rigid Registration of Brain Images"

On May 31st 2011 Petter Risholm defended his thesis “Intra-Operative Non-Rigid Registration of Brain Images” at Institute of Informatics at University of Oslo. The research is linked to University of Oslo's Centre of Mathematics for Applications, Department of Informatics and The Intervention Centre at Faculty of Medicine, and the Surgical Planning Lab, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School in Boston, USA.
The dissertation presents mathematical methods designed to align (register) medical brain images with complementary information to increase and enhance the available intra-operative information on which surgeons make clinical decisions during neurosurgeries. A typical example is to maximize tumor removal, while at the same time preserve eloquent areas of the brain such as sight or motoric centers.
In the image Dr. Petter Risholm is flanked by Dr. Ole Jakob Elle (left) from The Intervention Centre and Dr. Eigil Samset, one of Risholm's mentors.

Many factors contribute to complex local (non-rigid) movements of brain tissue during surgery which complicates the alignment of images. The methods are designed handle non-rigid shifts of brain tissue due to brain-shift, resection and retraction. Even more importantly, the dissertation also introduces a probabilistic framework for estimating the uncertainty involved in aligning two images. Being able to put “error bars” on registration results may reduce the risk involved in making clinical decision based on registered image data and increase the adoption of non-rigid registration methods for clinical use.