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Abstract #2935

Respiratory Gating of MRgHIFU Treatments in vivo Using an Optical Motion Tracking System

Vincent Auboiroux1, Lorena Petrusca1, Magalie Viallon2, Denis Morel3, Arnaud Muller4, Thomas Goget1, Joerg Roland5, Sylvain Terraz2, Christoph D. Becker2, R

1Faculty of Medicine, University of Geneva, Geneva, Switzerland; 2Radiology Department, Geneva University Hospital, Geneva, Switzerland; 3Anesthesiology Department, Geneva University Hospital, Geneva, Switzerland; 4MRI Center, Centre Hospitalier Lyon Sud, Lyon, France; 5Siemens Healthcare, Erlangen, Germany

An in-bore digital camera was used for the monitoring in real time of fiducial markers attached to the skin as direct estimators of the respiratory phase, in the context of interventional MRI for moving organs. The detection of the quiet-phase of exhalation based on in-bore optical acquisition allowed robust triggering of MR acquisitions (MR-ARFI and MR-thermometry) and HIFU sonications and yielded accurate ARFI and thermal maps, without measurable motion-induced artifacts. The feasibility of this no touch approach for the follow-up of the position in the respiratory cycle was demonstrated in vivo in sheep kidney and liver (trans-costal).

Keywords

abdominal ablative acoustic acquisition acquisitions adapted added additional allowed alternating amplitude anatomy anesthesiology application artifacts automatically blue border bore bursts calculation camera coil complicate consisted context contrarily coronal corrected correction curve cycle detected detection deviation digital direct displacement drift duration edge edges emitting employed enables encoding ensure estimation estimators example excitation exhalation external features fiducial field flow free gating general ghosting grade gradient guided hospital house improve in vivo included indirect induced inside inter interface iterative keeps kidney landmarks light like liver long markers material matrix measurable measuring mechanical monitoring morel motion moving objectives obstacle operated optical organ organs overall plotted plus polarity position power predictors preparation pressure procedures prospective pyramids quality quiet quite radiology readout real reconstruction repeatability resp respiratory retrospective rigid robust segmented sender sensor sensors sharp sheep shielding skin slice source spacing spoiled successive system thermometry tissue touch tracking transducer treatment triggering triggers twin user versatile view window written yield