{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T12:32:39Z","timestamp":1793449959970,"version":"4.5.0"},"reference-count":27,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2024,4,22]],"date-time":"2024-04-22T00:00:00Z","timestamp":1713744000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Neurol."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Skull density ratio (SDR) is the ratio between the mean Hounsfield units of marrow and cortical bone, impacting energy transmission through the skull. Low SDR has been used as an exclusion criterion in major trials of magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy for medication-refractory essential tremor (ET). However, some studies have suggested that patients with low SDR can safely undergo MRgFUS with favorable outcomes. In this case-matched study, we aim to compare the characteristics, sonication parameters, lesion sizes, and clinical outcomes of patients with low SDR vs. patients with high SDR who underwent unilateral MRgFUS thalamotomy for medication-refractory ET.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      Between March 2016 and April 2023, all patients (\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u2009270) who underwent unilateral MRgFUS thalamotomy for medication-refractory ET at a single institution were classified as low SDR (&amp;lt;0.40) and high SDR (\u22650.40). All clinical and radiological data was prospectively collected and retrospectively analyzed using non-case-matched and 1:1 case-matched methodology.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Thirty-one patients had low SDR, and 239 patients had high SDR. Fifty-six patients (28 in each cohort) were included in 1:1 case-matched analysis. There were no significant differences in baseline characteristics between the two groups in both non-case-matched and 1:1 case-matched analyses. In both analyses, compared to patients with high SDR, patients with low SDR required a significantly higher maximum sonication power, energy, and duration, and reached a lower maximum temperature with smaller lesion volumes. In the non-case-matched and case-matched analyses, low SDR patients did not have significantly less tremor control at any postoperative timepoints. However, there was a higher chance of procedure failure in the low SDR group with three patients not obtaining an appropriately sized lesion. In both analyses, imbalance was observed more often in high SDR patients on postoperative day 1 and month 3.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>ET patients with SDR &amp;lt;0.40 can be safely and effectively treated with MRgFUS, though there may be higher rates of treatment failure and intraoperative discomfort.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fneur.2024.1370574","type":"journal-article","created":{"date-parts":[[2024,4,22]],"date-time":"2024-04-22T07:49:47Z","timestamp":1713772187000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":15,"title":["Magnetic resonance-guided focused ultrasound thalamotomy for essential tremor patients with low skull density ratio: a case-matched analysis"],"prefix":"10.3389","volume":"15","author":[{"given":"Patrick R.","family":"Ng","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah E.","family":"Blitz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Melissa M. J.","family":"Chua","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"G. Rees","family":"Cosgrove","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2024,4,22]]},"reference":[{"key":"ref1","year":"2016"},{"key":"ref2","year":"2022"},{"key":"ref3","doi-asserted-by":"publisher","first-page":"E16","DOI":"10.3171\/2017.11.FOCUS17610","article-title":"High-intensity focused ultrasound: past, present, and future in neurosurgery","volume":"44","author":"Quadri","year":"2018","journal-title":"Neurosurg Focus"},{"key":"ref4","doi-asserted-by":"publisher","first-page":"730","DOI":"10.1056\/NEJMoa1600159","article-title":"A randomized trial of focused ultrasound Thalamotomy for essential tremor","volume":"375","author":"Elias","year":"2016","journal-title":"N Engl J Med"},{"key":"ref5","doi-asserted-by":"publisher","first-page":"e2284","DOI":"10.1212\/WNL.0000000000008561","article-title":"Three-year follow-up of prospective trial of focused ultrasound thalamotomy for essential tremor","volume":"93","author":"Halpern","year":"2019","journal-title":"Neurology"},{"key":"ref6","doi-asserted-by":"publisher","first-page":"1028","DOI":"10.3171\/2022.6.JNS212483","article-title":"Magnetic resonance imaging-guided focused ultrasound thalamotomy for essential tremor: 5-year follow-up results","volume":"138","author":"Cosgrove","year":"2023","journal-title":"J Neurosurg"},{"key":"ref7","doi-asserted-by":"publisher","first-page":"533","DOI":"10.1007\/s10143-021-01562-w","article-title":"Magnetic resonance-guided focused ultrasound treatment for essential tremor shows sustained efficacy: a meta-analysis","volume":"45","author":"Miller","year":"2022","journal-title":"Neurosurg Rev"},{"key":"ref8","doi-asserted-by":"publisher","first-page":"1785","DOI":"10.3171\/2019.2.JNS182571","article-title":"The relevance of skull density ratio in selecting candidates for transcranial MR-guided focused ultrasound","volume":"132","author":"Boutet","year":"2019","journal-title":"J Neurosurg"},{"key":"ref9","doi-asserted-by":"publisher","first-page":"411","DOI":"10.3171\/2015.3.JNS142592","article-title":"Factors associated with successful magnetic resonance-guided focused ultrasound treatment: efficiency of acoustic energy delivery through the skull","volume":"124","author":"Chang","year":"2016","journal-title":"J Neurosurg"},{"key":"ref10","doi-asserted-by":"publisher","first-page":"6588","DOI":"10.1002\/mp.15239","article-title":"Patient-specific effects on sonication heating efficiency during magnetic resonance-guided focused ultrasound thalamotomy","volume":"48","author":"Yang","year":"2021","journal-title":"Med Phys"},{"key":"ref11","doi-asserted-by":"publisher","first-page":"1392","DOI":"10.3171\/2019.2.JNS183517","article-title":"Impact of skull density ratio on efficacy and safety of magnetic resonance-guided focused ultrasound treatment of essential tremor","volume":"132","author":"D\u2019Souza","year":"2019","journal-title":"J Neurosurg"},{"key":"ref12","doi-asserted-by":"publisher","first-page":"1780","DOI":"10.3171\/2020.11.JNS202580","article-title":"Technical and operative factors affecting magnetic resonance imaging-guided focused ultrasound thalamotomy for essential tremor: experience from 250 treatments","volume":"135","author":"Kim","year":"2021","journal-title":"J Neurosurg"},{"key":"ref13","doi-asserted-by":"publisher","first-page":"743649","DOI":"10.3389\/fneur.2022.743649","article-title":"Magnetic resonance image guided focused ultrasound Thalamotomy. A single center experience with 160 procedures","volume":"13","author":"Lak","year":"2022","journal-title":"Front Neurol"},{"key":"ref14","doi-asserted-by":"publisher","first-page":"1802","DOI":"10.3171\/2019.2.JNS182995","article-title":"Accumulated thermal dose in MRI-guided focused ultrasound for essential tremor: repeated sonications with low focal temperatures","volume":"132","author":"Jones","year":"2019","journal-title":"J Neurosurg"},{"key":"ref15","doi-asserted-by":"publisher","first-page":"768","DOI":"10.3349\/ymj.2019.60.8.768","article-title":"Skull factors affecting outcomes of magnetic resonance-guided focused ultrasound for patients with essential tremor","volume":"60","author":"Chang","year":"2019","journal-title":"Yonsei Med J"},{"key":"ref16","doi-asserted-by":"publisher","first-page":"751","DOI":"10.1093\/neuros\/nyaa536","article-title":"Focused ultrasound Thalamotomy for refractory essential tremor: a Japanese multicenter single-arm 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tremor: a 5-year single-center experience","volume":"133","author":"Sinai","year":"2019","journal-title":"J Neurosurg"},{"key":"ref27","doi-asserted-by":"publisher","first-page":"1239","DOI":"10.1002\/mds.27726","article-title":"Ventralis intermedius thalamotomy with focused ultrasound for patients with low skull density ratio","volume":"34","author":"Yamamoto","year":"2019","journal-title":"Mov Disord"}],"container-title":["Frontiers in 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