R. Lasowski, S. Benhimane, J. Vogel, T. F. Jakobs, C. J. Zech, C. Trumm, Ch. Clason, N. Navab Adaptive visualization for needle guidance in RF Liver Ablation: taking organ deformation into account SPIE Medical Imaging, San Diego, California, USA, February 16-21, 2008 (bib)
	Interventional procedures on deformable organs pose difficulties for the radiologists when inserting the probe towards a lesion. The deformation due to the breathing makes a reliable and automated alignment of the interventional 2D CT-Fluoro to the pre-interventional 3D CT-Volume very challenging. Such alignment is highly desirable since, during the intervention, the CT-Volume brings more information as it is enhanced with contrast agent and has a higher resolution than the CT-Fluoro slice. A reasonable solution for the alignment is obtained by employing a robust optimization technique. However, since we would like to help the needle guidance towards the lesion, due to the involved deformation, a single slice of the 3D CT-Volume is not satisfactory. The main contribution of this paper consists in visualizing slices of the 3D CT-volume that are resulting from the out-of-plane motion parameters along weighted isosurfaces in the convergence basin of the similarity function used during the alignment. This visualization copes with the uncertainty in estimating the deformation and brings much more information than a single registered slice. Three experienced interventional radiologists were consulted and their evaluation clearly highlighted that such visualization unfolding the neighborhood with the belonging structures, like vessels and lesion spread, will help the needle guidance.
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