Impact of skull density ratio on efficacy and safety of magnetic resonance–guided focused ultrasound treatment of essential tremor

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  • 1 Departments of Neurosurgery and
  • 2 Radiology, Stanford University School of Medicine, Stanford, California;
  • 3 Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia;
  • 4 University of Maryland School of Medicine, Baltimore, Maryland;
  • 5 Swedish Neuroscience Institute, Seattle, Washington;
  • 6 Tokyo Women’s Medical University, Tokyo, Japan;
  • 7 Yonsei University College of Medicine, Seoul, Korea;
  • 8 Sunnybrook Health Sciences Center, Toronto, Ontario, Canada;
  • 9 The Ohio State University Medical Center, Columbus, Ohio;
  • 10 Washoukai Sadamoto Hospital, Matsuyama City, Japan;
  • 11 Kumamoto University Hospital, Obihiro City, Japan;
  • 12 Osaka University Hospital, Osaka, Japan;
  • 13 Brigham and Women’s Hospital, Boston, Massachusetts;
  • 14 ResoFUS Alomar, Barcelona, Spain;
  • 15 Weill Cornell School of Medicine, New York, New York;
  • 16 Nara Medical University, Kashihara, Japan;
  • 17 St. Mary’s Hospital, London, United Kingdom; and
  • 18 InSightec, Ltd., Dallas, Texas

OBJECTIVE

Skull density ratio (SDR) assesses the transparency of the skull to ultrasound. Magnetic resonance–guided focused ultrasound (MRgFUS) thalamotomy in essential tremor (ET) patients with a lower SDR may be less effective, and the risk for complications may be increased. To address these questions, the authors analyzed clinical outcomes of MRgFUS thalamotomy based on SDRs.

METHODS

In 189 patients, 3 outcomes were correlated with SDRs. Efficacy was based on improvement in Clinical Rating Scale for Tremor (CRST) scores 1 year after MRgFUS. Procedural efficiency was determined by the ease of achieving a peak voxel temperature of 54°C. Safety was based on the rate of the most severe procedure-related adverse event. SDRs were categorized at thresholds of 0.45 and 0.40, selected based on published criteria.

RESULTS

Of 189 patients, 53 (28%) had an SDR < 0.45 and 20 (11%) had an SDR < 0.40. There was no significant difference in improvement in CRST scores between those with an SDR ≥ 0.45 (58% ± 24%), 0.40 ≤ SDR < 0.45 (i.e., SDR ≥ 0.40 but < 0.45) (63% ± 27%), and SDR < 0.40 (49% ± 28%; p = 0.0744). Target temperature was achieved more often in those with an SDR ≥ 0.45 (p < 0.001). Rates of adverse events were lower in the groups with an SDR < 0.45 (p = 0.013), with no severe adverse events in these groups.

CONCLUSIONS

MRgFUS treatment of ET can be effectively and safely performed in patients with an SDR < 0.45 and an SDR < 0.40, although the procedure is more efficient when SDR ≥ 0.45.

ABBREVIATIONS CRST = Clinical Rating Scale for Tremor; ET = essential tremor; FUS = focused ultrasound; MRgFUS = magnetic resonance–guided focused ultrasound; SDR = skull density ratio.

Contributor Notes

Correspondence Pejman Ghanouni: Stanford University, Stanford, CA. ghanouni@stanford.edu.

INCLUDE WHEN CITING Published online April 26, 2019; DOI: 10.3171/2019.2.JNS183517.

C.H.H. and P.G. contributed equally to this work.

Disclosures InSightec provided research funding for clinical trials related to MRgFUS treatment of essential tremor. Drs. Ghanouni, Halpern, Henderson, Elias, Eisenberg, Gwinn, Taira, Chang, Lipsman, Krishna, Igase, Yamada, Kishima, Cosgrove, Rumià, Kaplitt, Hirabayashi, Eisenberg, and Nandi receive research funding from InSightec. Conduct of the study, data analysis and interpretation, and preparation and approval of the manuscript were done independently of InSightec. Initial design of the study was performed by Drs. Ghanouni, Halpern, and Dayan, who is an employee of InSightec. Data collection was performed by Dr. Dayan, who also reviewed the manuscript. Dr. Elias reports receiving support of non–study-related clinical or research efforts that he oversees from InSightec. Dr. Taira reports being a consultant for InSightec Japan. Dr. Lipsman reports having served as chair on the Expert Steering Committee of the Focused Ultrasound Foundation. Dr. Krishna reports receiving funding for a clinical trial from InSightec. Dr. Yamada reports receiving support for the study described from Hokuto Hospital. Dr. Cosgrove reports receiving research funding for clinical trials from InSightec. Dr. Halpern reports receiving speaking honoraria from Mazor Robotics and being a consultant for Medtronic. Dr. Ghanouni reports receiving support of non–study-related clinical or research efforts that he oversees from InSightec. Dr. Dayan is an employee of InSightec.

  • 1

    Abe K, Taira T: Focused ultrasound treatment, present and future. Neurol Med Chir (Tokyo) 57:386391, 2017

  • 2

    Bond AE, Elias WJ: Predicting lesion size during focused ultrasound thalamotomy: a review of 63 lesions over 3 clinical trials. Neurosurg Focus 44(2):E5, 2018

    • Search Google Scholar
    • Export Citation
  • 3

    Boutet A, Ranjan M, Zhong J, Germann J, Xu D, Schwartz ML, : Focused ultrasound thalamotomy location determines clinical benefits in patients with essential tremor. Brain 141:34053414, 2018

    • Search Google Scholar
    • Export Citation
  • 4

    Butts Pauly K, Federau C, Werner B, Halpern C, Ghanouni P: Inflection of temperature vs. power curve in tcMRgFUS: correlation with lesion location. J Therapeutic Ultrasound 4 (Suppl 1):A19, 2016 (Abstract A19)

    • Search Google Scholar
    • Export Citation
  • 5

    Chang JW, Park CK, Lipsman N, Schwartz ML, Ghanouni P, Henderson JM, : A prospective trial of magnetic resonance-guided focused ultrasound thalamotomy for essential tremor: results at the 2-year follow-up. Ann Neurol 83:107114, 2018

    • Search Google Scholar
    • Export Citation
  • 6

    Chang WS, Jung HH, Zadicario E, Rachmilevitch I, Tlusty T, Vitek S, : Factors associated with successful magnetic resonance-guided focused ultrasound treatment: efficiency of acoustic energy delivery through the skull. J Neurosurg 124:411416, 2016

    • Search Google Scholar
    • Export Citation
  • 7

    Elias WJ, Lipsman N, Ondo WG, Ghanouni P, Kim YG, Lee W, : a randomized trial of focused ultrasound thalamotomy for essential tremor. N Engl J Med 375:730739, 2016

    • Search Google Scholar
    • Export Citation
  • 8

    Fishman PS, Elias WJ, Ghanouni P, Gwinn R, Lipsman N, Schwartz M, : Neurological adverse event profile of magnetic resonance imaging-guided focused ultrasound thalamotomy for essential tremor. Mov Disord 33:843847, 2018

    • Search Google Scholar
    • Export Citation
  • 9

    Hughes A, Huang Y, Schwartz ML, Hynynen K: The reduction in treatment efficiency at high acoustic powers during MR-guided transcranial focused ultrasound thalamotomy for essential tremor. Med Phys 45:29252936, 2018

    • Search Google Scholar
    • Export Citation
  • 10

    Krishna V, Sammartino F, Agrawal P, Changizi BK, Bourekas E, Knopp MV, : Prospective tractography-based targeting for improved safety of focused ultrasound thalamotomy. Neurosurgery 84:160168, 2019

    • Search Google Scholar
    • Export Citation
  • 11

    Laitinen LV: Brain targets in surgery for Parkinson’s disease. Results of a survey of neurosurgeons. J Neurosurg 62:349351, 1985

  • 12

    Ravikumar VK, Parker JJ, Hornbeck TS, Santini VE, Pauly KB, Wintermark M, : Cost-effectiveness of focused ultrasound, radiosurgery, and DBS for essential tremor. Mov Disord 32:11651173, 2017

    • Search Google Scholar
    • Export Citation
  • 13

    Sammartino F, Beam DW, Snell J, Krishna V: Kranion, an open-source environment for planning transcranial focused ultrasound surgery: technical note. J Neurosurg [epub ahead of print March 1, 2019. DOI: 10.3171/2018.11.JNS181995]

    • Search Google Scholar
    • Export Citation
  • 14

    Schwartz ML, Yeung R, Huang Y, Lipsman N, Krishna V, Jain JD, : Skull bone marrow injury caused by MR-guided focused ultrasound for cerebral functional procedures. J Neurosurg 130:758762, 2019

    • Search Google Scholar
    • Export Citation
  • 15

    Vyas U, Ghanouni P, Halpern CH, Elias J, Pauly KB: Predicting variation in subject thermal response during transcranial magnetic resonance guided focused ultrasound surgery: comparison in seventeen subject datasets. Med Phys 43:51705180, 2016

    • Search Google Scholar
    • Export Citation
  • 16

    Wang TR, Bond AE, Dallapiazza RF, Blanke A, Tilden D, Huerta TE, : Transcranial magnetic resonance imaging-guided focused ultrasound thalamotomy for tremor: technical note. Neurosurg Focus 44(2):E3, 2018

    • Search Google Scholar
    • Export Citation
  • 17

    Webb TD, Leung SA, Rosenberg J, Ghanouni P, Dahl JJ, Pelc NJ, : Measurements of the relationship between CT Hounsfield units and acoustic velocity and how it changes with photon energy and reconstruction method. IEEE Trans Ultrason Ferroelectr Freq Control 65:11111124, 2018

    • Search Google Scholar
    • Export Citation
  • 18

    Zesiewicz TA, Chari A, Jahan I, Miller AM, Sullivan KL: Overview of essential tremor. Neuropsychiatr Dis Treat 6:401408, 2010

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