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Abstract #0244

Velocity Navigator Triggering for Motion Compensated PRF Thermometry

Florian Maier1, Axel Joachim Krafft1, Jrgen W. Jenne2,3, Rdiger Dillmann4, Wolfhard Semmler1, Michael Bock1

1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; 2Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany; 3Mediri GmbH, Heidelberg, Germany; 4Institute of Anthropomatics, Karlsruhe Institute of Technology, Karlsruhe, Germany

Proton resonance frequency shift thermometry is sensitive to motion. Artifacts are caused by tissue displacement and susceptibility changes. In this work, a novel navigator technique for triggering MR thermometry image acquisition is presented. Non-velocity and velocity encoded navigator signals were acquired without lengthening of TR. Based on the phase variation of non-encoded values and the estimated velocity, trigger events were generated. The measurements indicate that the proposed triggered segmented EPI pulse sequence allows for motion compensated thermometry of periodically moving tissue.