{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T18:51:09Z","timestamp":1792176669546,"version":"4.4.0"},"reference-count":28,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2019,8]]},"abstract":"<jats:sec><jats:title>OBJECTIVE<\/jats:title><jats:p>Gamma Knife radiosurgery (GKRS) is an important treatment modality for trigeminal neuralgia (TN). Current longitudinal assessment after GKRS relies primarily on clinical diagnostic measures, which are highly limited in the prediction of long-term clinical benefit. An objective, noninvasive, predictive tool would be of great utility to advance the clinical management of patients. Using diffusion tensor imaging (DTI), the authors\u2019 aim was to determine whether early (6 months post-GKRS) target diffusivity metrics can be used to prognosticate long-term pain relief in patients with TN.<\/jats:p><\/jats:sec><jats:sec><jats:title>METHODS<\/jats:title><jats:p>Thirty-seven patients with TN treated with GKRS underwent 3T MRI scans at 6 months posttreatment. Diffusivity metrics of fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity were extracted bilaterally from the radiosurgical target of the affected trigeminal nerve and its contralateral, unaffected nerve. Early (6 months post-GKRS) diffusivity metrics were compared with long-term clinical outcome. Patients were identified as long-term responders if they achieved at least 75% reduction in preoperative pain for 12 months or longer following GKRS.<\/jats:p><\/jats:sec><jats:sec><jats:title>RESULTS<\/jats:title><jats:p>Trigeminal nerve diffusivity at 6 months post-GKRS was predictive of long-term clinical effectiveness, where long-term responders (n = 19) showed significantly lower fractional anisotropy at the radiosurgical target of their affected nerve compared to their contralateral, unaffected nerve and to nonresponders. Radial diffusivity and mean diffusivity, correlates of myelin alterations and inflammation, were also significantly higher in the affected nerve of long-term responders compared to their unaffected nerve. Nonresponders (n = 18) did not exhibit any characteristic diffusivity changes after GKRS.<\/jats:p><\/jats:sec><jats:sec><jats:title>CONCLUSIONS<\/jats:title><jats:p>The authors demonstrate that early postsurgical target diffusivity metrics have a translational, clinical value and permit prediction of long-term pain relief in patients with TN treated with GKRS. Importantly, an association was found between the footprint of radiation and clinical effectiveness, where a sufficient level of microstructural change at the radiosurgical target is necessary for long-lasting pain relief. DTI can provide prognostic information that supplements clinical measures, and thus may better guide the postoperative assessment and clinical decision-making for patients with TN.<\/jats:p><\/jats:sec>","DOI":"10.3171\/2018.3.jns172936","type":"journal-article","created":{"date-parts":[[2018,8,17]],"date-time":"2018-08-17T14:00:13Z","timestamp":1534514413000},"page":"539-548","source":"Crossref","is-referenced-by-count":34,"title":["Early postsurgical diffusivity metrics for prognostication of long-term pain relief after Gamma Knife radiosurgery for trigeminal neuralgia"],"prefix":"10.3171","volume":"131","author":[{"given":"Sarasa","family":"Tohyama","sequence":"first","affiliation":[{"name":"Division of Brain, Imaging, and Behaviour\u2014Systems Neuroscience, Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto;"},{"name":"Collaborative Program in Neuroscience, University of Toronto; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter","family":"Shih-Ping Hung","sequence":"additional","affiliation":[{"name":"Division of Brain, Imaging, and Behaviour\u2014Systems Neuroscience, Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto;"},{"name":"Collaborative Program in Neuroscience, University of Toronto; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jidan","family":"Zhong","sequence":"additional","affiliation":[{"name":"Division of Brain, Imaging, and Behaviour\u2014Systems Neuroscience, Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mojgan","family":"Hodaie","sequence":"additional","affiliation":[{"name":"Division of Brain, Imaging, and Behaviour\u2014Systems Neuroscience, Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto;"},{"name":"Division of Neurosurgery, Krembil Neuroscience Centre, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"key":"b1","series-title":"AJNR Am J Neuroradiol","first-page":"1944","article-title":"Focal enhancement of cranial nerve V after radiosurgery with the Leksell gamma knife: experience in 15 patients with medically refractory trigeminal neuralgia","volume":"22","author":"Alberico RA","year":"2001","unstructured":"Alberico RA, Fenstermaker RA, Lobel J: Focal enhancement of cranial nerve V after radiosurgery with the Leksell gamma knife: experience in 15 patients with medically refractory trigeminal neuralgia. 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