Section: New Results

Interventional neuroradiology

Participants : Marie-Odile Berger, Charlotte Delmas, Erwan Kerrien, Raffaella Trivisonne.

Tools reconstruction for interventional neuro-radiology Minimally invasive techniques impact surgery in such ways that, in particular, an imaging modality is required to maintain a visual feedback. Live X-ray imaging, called fluoroscopy, is used in interventional neuroradiology. Such images are very noisy, and cannot show any brain tissue except the vasculature. In particular, since at most only two projective fluoroscopic views are available, containing absolutely no depth hint, the 3D shape of the micro-tool (guidewire, micro-catheter or micro-coil) can be very difficult, if not impossible to infer, which may have an impact on the clinical outcome of the procedure.

In collaboration with GE Healthcare, we aim at devising ways to reconstruct the micro-tools in 3D from fluoroscopy images. Charlotte Delmas has been working as a PhD CIFRE student on this subject since April 2013. A setup was designed in a view to reconstruct in 3D a deploying coil in as little X-ray dose and time as possible. It combines a fast rotation of both X-ray planes around the patient's head and a tomographic reconstruction combining an $l_1$-constraint to promote sparsity together with diffusion filters that promote the curvilinear nature of the coil. During this final year of her PhD thesis, various acquisition strategies and diffusion filters were evaluated [20].

Image driven simulation We consider image-driven simulation, applied to interventional neuroradiology as a coupled system of interactive computer-based simulation (interventional devices in blood vessels) and on-line medical image acquisitions (X-ray fluoroscopy). The main idea is to use the live X-ray images as references to continuously refine the parameters used to simulate the blood vessels and the interventional devices (micro-guide, micro-catheter, coil).

Raffaella Trivisonne started her PhD thesis in November 2015 (co-supervised by Stéphane Cotin, from MIMESIS team in Strasbourg) to address this research topic. Both projective and mechanical constraints were integrated in an augmented Lagrangian framework to solve the dynamical system. Experiments based on synthetic and phantom data were indicative that the shape from template problem could be solved without the need for considering collisions with the vessel surface, if an efficient tracking of the catheter in the X-ray images is available. These results were submitted for publication at a conference.