PhD thesis: Automatic multimodal real-time tracking for image plane alignment in interventional Magnetic Resonance Imaging

PhD defense in medical imaging : Markus NEUMANN

Team : AVR

Title : Automatic multimodal real-time tracking for image plane alignment in interventional Magnetic Resonance Imaging

Abstract : Interventional magnetic resonance imaging (MRI) aims at performing minimally invasive percutaneous interventions, such as tumor ablations and biopsies, under MRI guidance. During such interventions, the acquired MR image planes are typically aligned to the surgical instrument (needle) axis and to surrounding anatomical structures of interest in order to efficiently monitor the advancement in real-time of the instrument inside the patient's body. Object tracking inside the MRI is expected to facilitate and accelerate MR-guided interventions by allowing to automatically align the image planes to the surgical instrument.
In this PhD thesis, an image-based workflow is proposed and refined for automatic image plane alignment. An automatic tracking workflow was developed, performing detection and tracking of a passive marker directly in clinical real-time images. This tracking workflow is designed for fully automated image plane alignment, with minimization of tracking-dedicated time. Its main drawback is its inherent dependence on the slow clinical MRI update rate. First, the addition of motion estimation and prediction with a Kalman filter improved the workflow tracking performance. Second, a complementary optical sensor was used for multi-sensor tracking in order to decouple the tracking update rate from the MR image acquisition rate. Performance of the workflow was evaluated with both computer simulations and experiments using an MR compatible testbed.
Results show a high robustness of the multi-sensor tracking approach for dynamic image plane alignment, due to the combination of the individual strengths of each sensor.

This thesis was directed by Michel de Mathelin, professor at the University of Strasbourg.

The presentation will take place on Tuesday February 25th at 2.00pm in the Hirsch amphitheater of IRCAD (1, place de l'Hôpital, 67091 Strasbourg).