Annals of Clinical and Experimental NeurologyAnnals of Clinical and Experimental Neurology2075-54732409-2533Research Center of Neurology87310.54101/ACEN.2023.1.3Research ArticleAssessing trigeminal microstructure changes in patients with classical trigeminal neuralgiaRozhnovaElizaveta N.<p>Neurologist</p>elizabett-eliz@yandex.ruhttps://orcid.org/0000-0003-0521-4836DashyanVladimir G.<p>D. Sci. (Med.), Senior Researcher, Neurosurgeon. N.V. Sklifosovsky Research Institute of Emergency Medicine; Professor, A.I. Yevdokimov Moscow State University of Medicine and Dentistry</p>v485@bk.ruhttps://orcid.org/0000-0002-5847-9435TokarevAleksey S.<p>Cand. Sci. (Med.), Neurosurgeon, N.V. Sklifosovsky Research Institute of Emergency Medicine</p>tokarev@neurosklif.ruhttps://orcid.org/0000-0002-8415-5602EvdokimovaOlga L.<p>Radiologist, Head, Radiosurgery Center, N.V. Sklifosovsky Research Institute of Emergency Medicine</p>liveryevna@yandex.ruhttps://orcid.org/0000-0001-8099-9544NeznanovaMaria V.<p>Radiologist, N.V. Sklifosovsky Research Institute of Emergency Medicine</p>mashaneznanova@inbox.ruhttps://orcid.org/0000-0002-0635-6783SinkinMikhail V.<p>D. Sci. (Med.), Senior Researcher, Neurologist, N.V. Sklifosovsky Research Institute of Emergency Medicine; Head, Laboratory of Invasive Neurointerfaces, A.I. Yevdokimov Moscow State University of Medicine and Dentistry</p>mvsinkin@gmail.comhttps://orcid.org/0000-0001-5026-0060N.V. Sklifosovsky Research Institute for Emergency MedicineA.I. Yevdokimov Moscow State University of Medicine and Dentistry2903202317120260208202207122022Copyright © 2023, Rozhnova E.N., Dashyan V.G., Tokarev A.S., Evdokimova O.L., Neznanova M.V., Sinkin M.V.2023<p><strong><em>Introduction.</em></strong> The crucial role of neuro-vascular conflict (NVC) in trigeminal neuralgia (TN) is getting increasingly challenged. Microstructural changes can be assessed using fractional anisotropy (FA) in diffusion tensor images (DTI).</p>
<p><strong><em>Objective. </em></strong>To evaluate usefulness of FA in brain MRI with DTI for TN lateralization assessment.</p>
<p><strong><em>Materials and methods. </em></strong>The study included 51 patients with classical TN divided into two groups: neurosurgical intervention free, post radiofrequency ablation (RFA), and a control group (patients without facial pain). All the patients were tested for NVC with FIESTA (Fast Imaging Employing Steady State Acquisition) brain MRI at 3Т. Difference in thickness of trigeminal roots on the intact and symptomatic sides was assessed for each group. The findings were compared to those in the control group. The MRI protocol was supplemented with DTI. The FA difference in thickness of the intact and symptomatic roots (∆FA) was calculated for each study group to assess microstructural root changes. The results were compared to those in the control group.</p>
<p><strong><em>Results. </em></strong>In trigeminal root DTIs, ∆FA over 0.075 [0.029; 0.146] is statistically significant to establish NVC-associated microstructural changes on the symptomatic side in patients without any past surgeries (p = 0,030). In patients with a history of trigeminal ganglion RFA, statistically significant (p = 0.026) thinned symptomatic trigeminal root (difference in thickness of trigeminal roots over 0.45 cm [0.4; 0.6]) was found as compared to that of the control patients.</p>
<p><strong><em>Conclusion.</em></strong> FA may be used as a quantitative demyelination biomarker in clinical TN. Trigeminal ganglion RFA leads to hypotrophy throughout the trigeminal nerve root.</p>diffusion tensor imagesfractional anisotropytrigeminal neuralgianeuro-vascular conflictmagnetic resonance imagingdemyelinationдиффузионно-тензорные изображенияфракционная анизотропиятригеминальная невралгияневралгия тройничного нерванейроваскулярный конфликтмагнитно-резонансная томографиядемиелинизация[Bendtsen L., Zakrzewska J.M., Abbott J. et al. European Academy of Neurology guideline on trigeminal neuralgia. Eur. J. Neurol. 2019; 26(6): 831–869. doi: 10.1111/ene.13950][Sindou M., Howeidy T., Acevedo G. Anatomical observations during microvascular decompression for idiopathic trigeminal neuralgia. Prospective study in a series of 579 patients. Acta Neurochir. (Wien). 2002; 144(1): 1–13. doi: 10.1007/s701-002-8269-4][Mukherjee P., Chung S.W., Berman J.I. et al. Diffusion tensor MR imaging and fiber tractography: technical considerations. AJNR Am. J. Neuroradiol. 2008; 29(5): 843–852. doi: 10.3174/ajnr.A1052][Tournier J.D., Mori S., Leemans A. Diffusion tensor imaging and beyond. Magn. Reson. Med. 2011; 65(6): 1532–1556. doi: 10.1002/mrm.22924][Lutz J., Thon N., Stahl R. et al. Microstructural alterations in trigeminal neuralgia determined by diffusion tensor imaging are independent of symptom duration, severity, and type of neurovascular conflict. J. Neurosurg. 2016; 124(3): 823–830. doi: 10.3171/2015.2.JNS142587][Herweh C., Kress B., Rasche D. et al. Loss of anisotropy in trigeminal neuralgia revealed by diffusion tensor imaging. Neurology. 2007; 68(10): 776–778. doi: 10.1212/01.wnl.0000256340.16766.1d][Liu Y., Li J., Butzkueven H. et al. Microstructural abnormalities in the trigeminal nerves of patients with trigeminal neuralgia revealed by multiple diffusion metrics. Eur. J. Radiol. 2013; 82(5): 783–786. doi: 10.1016/j.ejrad.2012.11.027][Fujiwara S., Sasaki M., Wada T. et al. High-resolution diffusion tensor imaging for the detection of diffusion abnormalities in the trigeminal nerves of patients with trigeminal neuralgia caused by neurovascular compression. J. Neuroimaging. 2011; 21(2): e102–108. doi: 10.1111/j.1552-6569.2010.00508.x][Leal P.R.L., Roch J., Hermier M. et al. Diffusion tensor imaging abnormalities of the trigeminal nerve root in patients with classical trigeminal neuralgia: a pre- and postoperative comparative study 4 years after microvascular decompression. Acta Neurochir. (Wien). 2019; 161(7): 1415–1425. doi: 10.1007/s00701-019-03913-5][Dandy W.E. Concerning the cause of trigeminal neuralgia. Am. J. Surg. 1934; 24(2): 447–455. doi: 10.1016/S0002-9610(34)90403-7][Adams C.B. Microvascular compression: an alternative view and hypothesis. J. Neurosurg. 1989; 70(1): 1–12. doi: 10.3171/jns.1989.70.1.0001][Miller J.P., Acar F., Hamilton B.E., Burchiel K.J. Radiographic evaluation of trigeminal neurovascular compression in patients with and without trigeminal neuralgia. J. Neurosurg. 2009; 110(4): 627–632. doi: 10.3171/2008.6.17620][Lee A., McCartney S., Burbidge C. et al. Trigeminal neuralgia occurs and recurs in the absence of neurovascular compression. J. Neurosurg. 2014; 120(5): 1048–1054. doi: 10.3171/2014.1.JNS131410]