Lucia I Navarro de Lara1, Martin Tik1, Michael Woletz1, Roberta Frass-Kriegl1, Ewald Moser1, Elmar Laistler1, Christian Windischberger2. 1. Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Guertel 18-20, A-1090 Wien, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria. 2. Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Währinger Guertel 18-20, A-1090 Wien, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria. Electronic address: christian.windischberger@meduniwien.ac.at.
Abstract
PURPOSE: To validate a novel setup for concurrent TMS/fMRI in the human motor cortex based on a dedicated, ultra-thin, multichannel receive MR coil positioned between scalp and TMS system providing greatly enhanced sensitivity compared to the standard birdcage coil setting. METHODS: A combined TMS/fMRI design was applied over the primary motor cortex based on 1Hz stimulation with stimulation levels of 80%, 90%, 100%, and 110% of the individual active motor threshold, respectively. Due to the use of a multichannel receive coil we were able to use multiband-accelerated (MB=2) EPI sequences for the acquisition of functional images. Data were analysed with SPM12 and BOLD-weighted signal intensity time courses were extracted in each subject from two local maxima (individual functional finger tapping localiser, fixed MNI coordinate of the hand knob) next to the hand area of the primary motor cortex (M1) and from the global maximum. RESULTS: We report excellent image quality without noticeable signal dropouts or image distortions. Parameter estimates in the three peak voxels showed monotonically ascending activation levels over increasing stimulation intensities. Across all subjects, mean BOLD signal changes for 80%, 90%, 100%, 110% of the individual active motor threshold were 0.43%, 0.63%, 1.01%, 2.01% next to the individual functional finger tapping maximum, 0.73%, 0.91%, 1.34%, 2.21% next to the MNI-defined hand knob and 0.88%, 1.09%, 1.65%, 2.77% for the global maximum, respectively. CONCLUSION: Our results show that the new setup for concurrent TMS/fMRI experiments using a dedicated MR coil array allows for high-sensitivity fMRI particularly at the site of stimulation. Contrary to the standard birdcage approach, the results also demonstrate that the new coil can be successfully used for multiband-accelerated EPI acquisition. The gain in flexibility due to the new coil can be easily combined with neuronavigation within the MR scanner to allow for accurate targeting in TMS/fMRI experiments.
PURPOSE: To validate a novel setup for concurrent TMS/fMRI in the human motor cortex based on a dedicated, ultra-thin, multichannel receive MR coil positioned between scalp and TMS system providing greatly enhanced sensitivity compared to the standard birdcage coil setting. METHODS: A combined TMS/fMRI design was applied over the primary motor cortex based on 1Hz stimulation with stimulation levels of 80%, 90%, 100%, and 110% of the individual active motor threshold, respectively. Due to the use of a multichannel receive coil we were able to use multiband-accelerated (MB=2) EPI sequences for the acquisition of functional images. Data were analysed with SPM12 and BOLD-weighted signal intensity time courses were extracted in each subject from two local maxima (individual functional finger tapping localiser, fixed MNI coordinate of the hand knob) next to the hand area of the primary motor cortex (M1) and from the global maximum. RESULTS: We report excellent image quality without noticeable signal dropouts or image distortions. Parameter estimates in the three peak voxels showed monotonically ascending activation levels over increasing stimulation intensities. Across all subjects, mean BOLD signal changes for 80%, 90%, 100%, 110% of the individual active motor threshold were 0.43%, 0.63%, 1.01%, 2.01% next to the individual functional finger tapping maximum, 0.73%, 0.91%, 1.34%, 2.21% next to the MNI-defined hand knob and 0.88%, 1.09%, 1.65%, 2.77% for the global maximum, respectively. CONCLUSION: Our results show that the new setup for concurrent TMS/fMRI experiments using a dedicated MR coil array allows for high-sensitivity fMRI particularly at the site of stimulation. Contrary to the standard birdcage approach, the results also demonstrate that the new coil can be successfully used for multiband-accelerated EPI acquisition. The gain in flexibility due to the new coil can be easily combined with neuronavigation within the MR scanner to allow for accurate targeting in TMS/fMRI experiments.
Authors: Bruce Luber; Simon W Davis; Zhi-De Deng; David Murphy; Andrew Martella; Angel V Peterchev; Sarah H Lisanby Journal: Neuroimage Date: 2021-12-30 Impact factor: 6.556
Authors: Lucia I Navarro de Lara; Laleh Golestanirad; Sergey N Makarov; Jason P Stockmann; Lawrence L Wald; Aapo Nummenmaa Journal: Magn Reson Med Date: 2020-01-23 Impact factor: 4.668
Authors: Heidi Gröhn; Bernadette T Gillick; Ivan Tkáč; Petr Bednařík; Daniele Mascali; Dinesh K Deelchand; Shalom Michaeli; Gregg D Meekins; Michael J Leffler-McCabe; Colum D MacKinnon; Lynn E Eberly; Silvia Mangia Journal: Front Neurosci Date: 2019-11-27 Impact factor: 4.677