sequences, IR sequences have been found to be superior to routine T1W imaging ( Table 2 ). 62 , 69 Limitations As recently as 15 years ago, indirect targeting based on anatomical landmarks was the mainstay of preoperative surgical planning for most functional neurosurgery services. However, advances in MRI hardware and techniques have allowed direct targeting to become more accessible and clinically feasible. 25 Despite these improvements, there is limited consensus on the optimal MRI sequences for direct visualization of common DBS targets. While addressing
Alexandre Boutet, Aaron Loh, Clement T. Chow, Alaa Taha, Gavin J. B. Elias, Clemens Neudorfer, Jurgen Germann, Michelle Paff, Ludvic Zrinzo, Alfonso Fasano, Suneil K. Kalia, Christopher J. Steele, David Mikulis, Walter Kucharczyk, and Andres M. Lozano
Christopher S. Lozano, Manish Ranjan, Alexandre Boutet, David S. Xu, Walter Kucharczyk, Alfonso Fasano, and Andres M. Lozano
electrophysiology, as shown here, or perioperative imaging. 6 , 8 Acknowledgments A.M.L. holds the RR Tasker Chair in Functional Neurosurgery and a Tier 1 Canada Research Chair in Neuroscience. Disclosures A.F. is a consultant for Medtronic and Boston Scientific. A.M.L. is a consultant for Medtronic, St. Jude, and Boston Scientific. Author Contributions Conception and design: AM Lozano, CS Lozano. Acquisition of data: AM Lozano, CS Lozano, Ranjan, Boutet, Xu. Analysis and interpretation of data: all authors. Drafting the article: CS Lozano. Critically revising the article: AM
Philippe De Vloo, Alexandre Boutet, Gavin J. B. Elias, Robert M. Gramer, Suresh E. Joel, Maheleth Llinas, Walter Kucharczyk, Alfonso Fasano, Clement Hamani, and Andres M Lozano
5513N), the European Society for Stereotactic Functional Neurosurgery (2016 research grant), and the Healers Foundation, as well as grants for education and travel from EANS, FWO, KU Leuven, Medtronic, Boston Scientific, and St. Jude–Abbott. Author Contributions Conception and design: De Vloo, Elias, Gramer, Lozano. Acquisition of data: De Vloo, Boutet, Elias, Gramer, Joel, Llinas, Kucharczyk. Analysis and interpretation of data: De Vloo, Boutet, Elias, Gramer, Joel, Fasano, Hamani. Drafting the article: De Vloo, Elias. Critically revising the article: Boutet
Ailish Coblentz, Gavin J. B. Elias, Alexandre Boutet, Jurgen Germann, Musleh Algarni, Lais M. Oliveira, Clemens Neudorfer, Elysa Widjaja, George M. Ibrahim, Suneil K. Kalia, Mehr Jain, Andres M. Lozano, and Alfonso Fasano
, facilitating programming, and informing disease pathophysiology. Acknowledgments This work was supported by the German Research Foundation (Deutsche Forshungsgemeinschaft, DFG NE 2276/1-1; C.N.), the RR Tasker Chair in Functional Neurosurgery at University Health Network, a Tier 1 Canada Research Chair in Neuroscience (A.M.L.), and the Chair in Neuromodulation and Multi-Disciplinary Care at UofT/UHN (A.F.). Dr. Coblentz was responsible for the data analysis. The corresponding author confirms that he had full access to all the data in the study and had final responsibility
Alexandre Boutet, Ileana Hancu, Utpal Saha, Adrian Crawley, David S. Xu, Manish Ranjan, Eugen Hlasny, Robert Chen, Warren Foltz, Francesco Sammartino, Ailish Coblentz, Walter Kucharczyk, and Andres M. Lozano
other institutions. As a large proportion of MRI centers surveyed in a prior study 25 banned MRI scanning of DBS patients, we also hope these findings will be a step toward decreased restrictions on MRI use in the care of DBS patients—often clinically required and potentially a powerful research tool. Acknowledgments We would like to thank our medical illustrator, Joyce Hui, for helping with the figure designs. This work was supported by the RR Tasker Chair in Functional Neurosurgery at University Health Network and a Tier 1 Canada Research Chair in Neuroscience
Alexandre Boutet, Dave Gwun, Robert Gramer, Manish Ranjan, Gavin J. B. Elias, David Tilden, Yuexi Huang, Stanley Xiangyu Li, Benjamin Davidson, Hua Lu, Pascal Tyrrell, Ryan M. Jones, Alfonso Fasano, Kullervo Hynynen, Walter Kucharczyk, Michael L. Schwartz, and Andres M. Lozano
adequate clinical benefit. As such, SDR should be complementary, not deterministic, in selecting who receives MRgFUS, as further study is still required to expound the implications of extremely low SDR values on clinical efficacy. Acknowledgments This work was supported by the R.R. Tasker Chair in Functional Neurosurgery at University Health Network and a Tier 1 Canada Research Chair in Neuroscience. Disclosures The study was partially supported by Insightec. Insightec assisted by calculating the SDR, but otherwise, had no role in data acquisition, analysis, or
Manish Ranjan, Gavin J. B. Elias, Alexandre Boutet, Jidan Zhong, Powell Chu, Jurgen Germann, Gabriel A. Devenyi, M. Mallar Chakravarty, Alfonso Fasano, Kullervo Hynynen, Nir Lipsman, Clement Hamani, Walter Kucharczyk, Michael L. Schwartz, Andres M. Lozano, and Mojgan Hodaie
Tractography-based targeting of the thalamic ventral intermediate nucleus (T-VIM) is a novel method conferring patient-specific selection of VIM coordinates for tremor surgery; however, its accuracy and clinical utility in magnetic resonance imaging–guided focused ultrasound (MRgFUS) thalamotomy compared to conventional indirect targeting has not been specifically addressed. This retrospective study sought to compare the treatment locations and potential adverse effect profiles of T-VIM with indirect targeting in a large cohort of MRgFUS thalamotomy patients.
T-VIM was performed using diffusion tractography outlining the pyramidal and medial lemniscus tracts in 43 MRgFUS thalamotomy patients. T-VIM coordinates were compared with the indirect treatment coordinates used in the procedure. Thalamotomy lesions were delineated on postoperative T1-weighted images and displaced (“translated”) by the anteroposterior and mediolateral difference between T-VIM and treatment coordinates. Both translated and actual lesions were normalized to standard space and subsequently overlaid with areas previously reported to be associated with an increased risk of motor and sensory adverse effects when lesioned during MRgFUS thalamotomy.
T-VIM coordinates were 2.18 mm anterior and 1.82 mm medial to the “final” indirect treatment coordinates. Translated lesions lay more squarely within the boundaries of the VIM compared to nontranslated lesions and showed significantly less overlap with areas associated with sensory adverse effects. Translated lesions overlapped less with areas associated with motor adverse effects; however, this difference was not significant.
T-VIM leads to the selection of more anterior and medial coordinates than the conventional indirect methods. Lesions moved toward these anteromedial coordinates avoid areas associated with an increased risk of motor and sensory adverse effects, suggesting that T-VIM may improve clinical outcomes.
Alexandre Boutet, Gavin J. B. Elias, Robert Gramer, Clemens Neudorfer, Jürgen Germann, Asma Naheed, Nicole Bennett, Bryan Li, Dave Gwun, Clement T. Chow, Ricardo Maciel, Alejandro Valencia, Alfonso Fasano, Renato P. Munhoz, Warren Foltz, David Mikulis, Ileana Hancu, Suneil K. Kalia, Mojgan Hodaie, Walter Kucharczyk, and Andres M. Lozano
acknowledge Eric Fiveland for his technical expertise and Hadiqa Malik for her help with the research ethics proposal. Disclosures This work was supported by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG NE 2276/1-1) with funding to C.N., the RR Tasker Chair in Functional Neurosurgery at University Health Network, and a Tier 1 Canada Research Chair in Neuroscience. A.B. was responsible for the data analysis. The corresponding author confirms that he had full access to all the data in the study and had final responsibility for the decision to submit