PURPOSE: Magnetic resonance-guided high-intensity focused ultrasound is considered to be a promising treatment for localized cancer in abdominal organs such as liver, pancreas, or kidney. Abdominal motion, anatomical arrangement, and required sustained sonication are the main challenges. METHODS: MR acquisition consisted of thermometry performed with segmented gradient-recalled echo echo-planar imaging, and a segment-based one-dimensional MR navigator parallel to the main axis of motion to track the organ motion. This tracking information was used in real-time for: (i) prospective motion correction of MR thermometry and (ii) HIFU focal point position lock-on target. Ex vivo experiments were performed on a sheep liver and a turkey pectoral muscle using a motion demonstrator, while in vivo experiments were conducted on two sheep liver. RESULTS: Prospective motion correction of MR thermometry yielded good signal-to-noise ratio (range, 25 to 35) and low geometric distortion due to the use of segmented EPI. HIFU focal point lock-on target yielded isotropic in-plane thermal build-up. The feasibility of in vivo intercostal liver treatment was demonstrated in sheep. CONCLUSION: The presented method demonstrated in moving phantoms and breathing sheep accurate motion-compensated MR thermometry and precise HIFU focal point lock-on target using only real-time pencil-beam navigator tracking information, making it applicable without any pretreatment data acquisition or organ motion modeling.
PURPOSE: Magnetic resonance-guided high-intensity focused ultrasound is considered to be a promising treatment for localized cancer in abdominal organs such as liver, pancreas, or kidney. Abdominal motion, anatomical arrangement, and required sustained sonication are the main challenges. METHODS: MR acquisition consisted of thermometry performed with segmented gradient-recalled echo echo-planar imaging, and a segment-based one-dimensional MR navigator parallel to the main axis of motion to track the organ motion. This tracking information was used in real-time for: (i) prospective motion correction of MR thermometry and (ii) HIFU focal point position lock-on target. Ex vivo experiments were performed on a sheep liver and a turkey pectoral muscle using a motion demonstrator, while in vivo experiments were conducted on two sheep liver. RESULTS: Prospective motion correction of MR thermometry yielded good signal-to-noise ratio (range, 25 to 35) and low geometric distortion due to the use of segmented EPI. HIFU focal point lock-on target yielded isotropic in-plane thermal build-up. The feasibility of in vivo intercostal liver treatment was demonstrated in sheep. CONCLUSION: The presented method demonstrated in moving phantoms and breathing sheep accurate motion-compensated MR thermometry and precise HIFU focal point lock-on target using only real-time pencil-beam navigator tracking information, making it applicable without any pretreatment data acquisition or organ motion modeling.
Authors: Tetiana Dadakova; Johanna Gellermann; Otilia Voigt; Jan Gerrit Korvink; John Matthew Pavlina; Jürgen Hennig; Michael Bock Journal: MAGMA Date: 2014-11-08 Impact factor: 2.310
Authors: Pelin Aksit Ciris; Cheng-Chieh Cheng; Chang-Sheng Mei; Lawrence P Panych; Bruno Madore Journal: Magn Reson Med Date: 2016-03-10 Impact factor: 4.668
Authors: Michael Schwenke; Jan Strehlow; Daniel Demedts; Sabrina Haase; Diego Barrios Romero; Sven Rothlübbers; Caroline von Dresky; Stephan Zidowitz; Joachim Georgii; Senay Mihcin; Mario Bezzi; Christine Tanner; Giora Sat; Yoav Levy; Jürgen Jenne; Matthias Günther; Andreas Melzer; Tobias Preusser Journal: J Ther Ultrasound Date: 2017-07-24
Authors: Thomas Günther Lesser; Harald Schubert; Daniel Güllmar; Jürgen R Reichenbach; Frank Wolfram Journal: Eur J Med Res Date: 2016-03-08 Impact factor: 2.175