Feasibility study of B-spline deformable registration between CT and MRI atlas for trigeminal neuralgia application to radiosurgery

Abstract

The objective of this work is to extend a B-spline deformable registration method to the multi-modality problem of matching a T1 Magnetic Resonance (MR) atlas to a Computed Tomography (CT) scan for improving image guidance in radiosurgery treatments of trigeminal neuralgia (TN). Trigeminal Rhyzotomy has been used in an attempt to alleviate TN in patients in whom pharmaceutical treatment fails in pain control or induces unendurable side effects. We tested the developed algorithm on a two patients dataset, using a 3 Tesla MR scan as ground truth. The validation was conducted by means of visual inspection and computing the surface distance between the trigeminal nerve outlined both on the warped atlas and CT. Three raters contoured the region of interest on both scans, thus providing inter-rater accuracy evaluation. Good results in terms of qualitative trigeminal nerve overlap were supported by the median distance (below 1.3mm and 1.5mm for patient 1 and 2, respectively) and the consistency between the raters judgment. Though subject to inaccuracies mainly caused by manual contouring variations, suggest the proposed approach can be a valid alternative to 3Tesla MR scanning.