3D motion strategy for online volumetric thermometry using simultaneous multi-slice EPI at 1.5T: an evaluation study. (31st December 2023)

• Record Type: Journal Article
• Authors: Ozenne, Valéry; Bour, Pierre; Denis de Senneville, Baudouin; Quesson, Bruno
• Is Part Of: International journal of hyperthermia. Volume 40:Number 1(2023)
• Publication Date: 2023-12-31
• Subjects: Thermometry -- registration -- echo planar imaging -- simultaneous multi-slice -- respiratory motion -- thermo-ablation; Thermotherapy -- Periodicals; 615.832
• DOI: 10.1080/02656736.2023.2194595
• Languages: English
• ISSNs: 0265-6736

Abstract

Abstract: Purpose: In presence of respiratory motion, temperature mapping is altered by in-plane and through-plane displacements between successive acquisitions together with periodic phase variations. Fast 2D Echo Planar Imaging (EPI) sequence can accommodate intra-scan motion, but limited volume coverage and inter-scan motion remain a challenge during free-breathing acquisition since position offsets can arise between the different slices. Method: To address this limitation, we evaluated a 2D simultaneous multi-slice EPI sequence with multiband (MB) acceleration during radiofrequency ablation on a mobile gel and in the liver of a volunteer (no heating). The sequence was evaluated in terms of resulting inter-scan motion, temperature uncertainty and elevation, potential false-positive heating and repeatability. Lastly, to account for potential through-plane motion, a 3D motion compensation pipeline was implemented and evaluated. Results: In-plane motion was compensated whatever the MB factor and temperature distribution was found in agreement during both the heating and cooling periods. No obvious false-positive temperature was observed under the conditions being investigated. Repeatability of measurements results in a 95% uncertainty below 2 °C for MB1 and MB2. Uncertainty up to 4.5 °C was reported with MB3 together with the presence of aliasing artifacts. Lastly, fast simultaneous multi-slice EPI combined with 3D motion compensation reduce residual out-of-plane motion. Conclusion: Volumetric temperature imaging (12 slices/700 ms) could be performed with 2 °C accuracy or less, and offer tradeoffs in acquisition time or volume coverage. Such a strategy is expected to increase procedure safety by monitoring large volumes more rapidly for MR-guided thermotherapy on mobile organs.