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Title

Ultrasonography-based 2D motion-compensated HIFU sonication integrated with reference-free MR temperature monitoring: a feasibility study ex vivo

Authors
Viallon, Magalie
Published in Physics in Medicine and Biology. 2012, vol. 57, no. 10, p. N159-71
Abstract Magnetic resonance imaging (MRI) and ultrasonography have been used simultaneously in this ex vivo study for the image-guidance of high intensity focused ultrasound (HIFU) treatment in moving tissue. A ventilator-driven balloon produced periodic and non-rigid (i.e. breathing-like) motion patterns in phantoms. MR-compatible ultrasound (US) imaging enabled near real-time 2D motion tracking based on optical flow detection, while near-harmonic reference-free proton resonance frequency shift (PRFS) MR thermometry (MRT) was used to monitor the thermal buildup on line. Reference-free MRT was applied to gradient-echo echo-planar imaging phase maps acquired at the frame rate of 250 to 300 ms/slice with voxel size 1.25×1.25×5 mm(3). The MR-US simultaneous imaging was completely free of mutual interferences while minor RF interferences from the HIFU device were detected in the far field of the US images. The effective duty-cycle of the HIFU sonication was close to 100 % and no off-interval was required to temporally decouple it from the ultrasonography. The motion compensation of the HIFU sonication was achieved with an 8 Hz frame rate and sub-millimeter spatial accuracy, both for single-focus mode and for an iterated multi-foci line scan. Near harmonic reference-less PRFS MRT delivered motion-robust thermal maps perpendicular or parallel to the HIFU beam (0.7 °C precision, 0.5 °C absolute accuracy). Out-of-plane motion compensation was not addressed in this study.
Keywords Feasibility StudiesHigh-Intensity Focused Ultrasound Ablation/instrumentation/methodsMagnetic Resonance Imaging/methodsMovementPhantoms, ImagingSonication/methodsSystems IntegrationTemperatureUltrasonography/methods
Identifiers
PMID: 22517112
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Article (Published version) (838 Kb) - document accessible for UNIGE members only Limited access to UNIGE
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Research groups Imagerie et radiologie interventionnelle du foie, des voies biliaires et du pancréas (316)
Imagerie per-opératoire multi-modalité en radiologie interventionnelle (949)
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AUBOIROUX, Vincent et al. Ultrasonography-based 2D motion-compensated HIFU sonication integrated with reference-free MR temperature monitoring: a feasibility study ex vivo. In: Physics in Medicine and Biology, 2012, vol. 57, n° 10, p. N159-71. https://archive-ouverte.unige.ch/unige:43196

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Deposited on : 2014-12-12

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