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Siva, Aksel

0000-0002-8340-6641

Mayo Clinic

Cerraphasa University, Istanbul, Turkiye.

Citations 33

Subclinical Optic Nerve Involvement in Radiologically Isolated Syndrome: Multimodal Detection and Diagnostic Impact
Lebrun‐Frénay, Christine , Landes-Château, Cassandre , Mondot, Lydiane , Cohen, Mikaël , Popolo, Margherita , Sèze, de , Bourre, Bertrand , Casez, Olivier , Kantarci, Orhun H. , Baillif, Stéphanie, Seze, Jerome De , Durand-Dubief, Françoise , Casez, Olivier , Kantarci, OH , Siva, Aksel , Baillif, Stephanie , Okuda, Darin T , Leocani, Letizia , Lebrun‐Frénay, Christine , Bourre, Bertrand , Cohen, Mikaël , Mondot, Lydiane , Durand‐Dubief, Françoise , Sıva, Aksel , Okuda, Darin T.

Annals of Clinical and Translational Neurology | June 2, 2026 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.1002/acn3.70441 Get It

ABSTRACT Objectives We aimed to determine the frequency of subclinical optic nerve (ON) lesions using MRI, optical coherence tomography (OCT), and visual evoked potentials (VEP) in radiologically isolated syndrome (RIS), and to assess their diagnostic and prognostic significance. Methods We conducted a retrospective, multicenter study of 179 RIS individuals followed in clinical practice who met the 2023 RISC criteria. The diagnostic performance of the 2024 McDonald criteria, with and without optic nerve assessment, was evaluated and compared with that of the 2017 criteria. Associations with clinical conversion, comorbidities, and MRI disease activity were analyzed using multivariate models. Results Silent ON lesions appeared in 107/179 (59.8%) individuals, mainly detected by VEP (100/164; 61.0%) and OCT (69/118; 58.5%), with routine MRI identifying 31/166 (18.7%). During follow‐up, 71 (39.7%) had a first clinical event. The presence, laterality, or number of silent ON lesions did not correlate with clinical conversion, event type, or MRI activity. Younger age and the absence of comorbidities associated with other MRI lesions, rather than with ON lesions, were associated with clinical conversion. Including ON in the 2024 McDonald criteria increased sensitivity but decreased specificity, with 17/179 (9.5%) meeting dissemination‐in‐space criteria solely due to ON lesions. Interpretation Subclinical ON lesions are common in RIS and are mainly found by OCT and VEP, not routine MRI. Including ON increases sensitivity but does not predict clinical conversion and may lower specificity. These findings suggest cautious interpretation of ON and support a multimodal assessment approach in RIS.
Do MRI-negative relapses really exist? Commentary
Siva, Aksel, Kantarci, OH , Sıva, Aksel , Siva, Aksel , Kantarci, Orhun H.

Multiple Sclerosis Journal | March 3, 2026 | Volume: 32 | Issue: 9 | Pages: 901-902

10.1177/13524585261423082 Get It

Analysis of healthcare utilization before the diagnosis of radiologically isolated syndrome
Lebrun‐Frénay, Christine , Kerbrat, Sandrine , Okuda, Darin T. , Landes-Château, Cassandre , Kantarci, Orhun H. , Pierret, Chloé , Drézen, Erwan , Nowak, Emmanuel, Sıva, Aksel , Azevedo, Christina , Cohen, Mikaël , Leray, Emmanuelle , Azevedo, Christina J , Lebrun‐Frénay, Christine , Siva, Aksel , Okuda, Darin T , Cohen, Mikaël

Multiple Sclerosis Journal | January 11, 2025 | Volume: 31 | Issue: 2 | Pages: 184-196

10.1177/13524585241291471 Get It

Background: Previous studies have shown that people with multiple sclerosis (MS) had frequent healthcare visits up to 10 years before being diagnosed but with no information from magnetic resonance imaging (MRI) scans of the connection with the radiologically isolated syndrome (RIS). Objective: To analyze healthcare use 3 years before the RIS diagnosis. Methods: We examined healthcare usage before the first scan in RIS cases from 2010 to 2019. RIS subjects were identified from the French National MS observatory and compared to the general population (matched 10:1) and MS patients (matched 4:1). Results: Among 482 RIS individuals, 223 (46.3%) were not linked to the healthcare resources database. The remaining RIS individuals (53.7%) had higher healthcare usage before their RIS diagnosis for issues related to neurology visits, headaches (odds ratio (OR): 3.34, confidence interval (CI): [2.00–5.57], p < 0.0001), and the use of anti-migraine drugs (OR: 2.61, CI: [1.37–4.99], p = 0.004) compared to MS. Conclusion: Only about half of RIS patients had MS-selected healthcare resources, which allowed for data linkage. Those who did seek care before their RIS diagnosis were most commonly known for other neurological comorbidities. These findings do not support the idea of a systemic prodrome before RIS diagnosis.
The diagnostic value of the central vein sign in radiologically isolated syndrome
Landes-Château, Cassandre , Levraut, Michaël , Okuda, Darin T. , Themelin, Albert, Cohen, Mikaël , Kantarci, Orhun H. , Sıva, Aksel , Pelletier, Daniel, Mondot, Lydiane , Lebrun‐Frénay, Christine , Lebrun‐Frénay, Christine , Siva, Aksel , Okuda, Darin T , Cohen, Mikaël , Mondot, Lydiane

Annals of Clinical and Translational Neurology | January 8, 2024 | Volume: 11 | Issue: 3 | Pages: 662-672

10.1002/acn3.51986 Get It

AbstractObjectiveThe radiologically isolated syndrome (RIS) represents the earliest detectable preclinical phase of multiple sclerosis (MS). Increasing evidence suggests that the central vein sign (CVS) enhances lesion specificity, allowing for greater MS diagnostic accuracy. This study evaluated the diagnostic performance of the CVS in RIS.MethodsPatients were prospectively recruited in a single tertiary center for MS care. Participants with RIS were included and compared to a control group of sex and age‐matched subjects. All participants underwent 3 Tesla magnetic resonance imaging, including postcontrast susceptibility‐based sequences, and the presence of CVS was analyzed. Sensitivity and specificity were assessed for different CVS lesion criteria, defined by proportions of lesions positive for CVS (CVS+) or by the absolute number of CVS+ lesions.Results180 participants (45 RIS, 45 MS, 90 non‐MS) were included, representing 5285 white matter lesions. Among them, 4608 were eligible for the CVS assessment (970 in RIS, 1378 in MS, and 2260 in non‐MS). According to independent ROC comparisons, the proportion of CVS+ lesions performed similarly in diagnosing RIS from non‐MS than MS from non‐MS (p = 0.837). When a 6‐lesion CVS+ threshold was applied, RIS lesions could be diagnosed with an accuracy of 87%. MS could be diagnosed with a sensitivity of 98% and a specificity of 83%. Adding OCBs or Kappa index to CVS biomarker increased the specificity to 100% for RIS diagnosis.InterpretationThis study shows evidence that CVS is an effective imaging biomarker in differentiating RIS from non‐MS, with similar performances to those in MS.
Teriflunomide and Time to Clinical Multiple Sclerosis in Patients With Radiologically Isolated Syndrome
Sıva, Aksel , Landes-Château, Cassandre , Mondot, Lydiane, Papeix, Caroline , Thouvenot, Éric , Labauge, Pierre, Durand‐Dubief, Françoise , Page, Emmanuelle Le , Terzi, Murat , Derache, Nathalie, Bourre, Bertrand , Hoepner, Robert , Karabudak, Rana , Ciron, Jonathan , Wiertlewski, Sandrine, Turan, Ömer Faruk , Yucear, Nur, Cohen, Mikaël , Azevedo, Christina , Kantarci, Orhun H. , Pelletier, Daniel , Group, TERIS Study, Branger, Pierre , Abrous, Mouloud, Petit, Julie, Gelet, Céline, Russello, Mélanie, Gaultier, Alina, Frère, Fabienne Le, Callier, Céline, Caillon, Cynthia, Gueydan, Eglantine, Louapre, Céline , Galanaud, Damien , Ungureanu, Aurelian , Coudoin, Sylvie, Hébant, Benjamin , Gerard, Emmanuel, Vimont, Christine, Bonneville, Fabrice , Freitas, Noellie, Kilic, Erhan , Destan, Sena, Friedli, Christoph , Wagner, Franca , Weber, Lea , Tchoubar, Annaig, Dumont, Émilie , Eryilmaz, Asli, Roman, Tanguy, Pelletreau, Christopher, Grateau, Aurélie, Mathieu, Yanica, Yaïche, Sarhan, Rintelen, Felix, Firmino, Isabel, Chastenier, Aymeric De, Gheribenblidia, Amel, Zeydan, Burcu , Siva, Aksel , Zeydan, Burcu , Thouvenot, Eric , Ciron, Jonathan , Durand-Dubief, Françoise , Cohen, Mikaël , Lebrun‐Frénay, Christine , Sormani, Maria Pia , Mondot, Lydiane , Bovis, Francesca , Vermersch, Patrick , Labauge, Pierre , Efendi, Hüsnü , Bourre, Bertrand , Seze, Jerome De , Clavelou, Pierre , Okuda, Darin T. , Group, TERIS Study, Zéphir, Hélène , Vukusic, Sandra , Carra‐Dallière, Clarisse , Ayrignac, Xavier , Laplaud, David , Biotti, Damien , Duman, Taşkın , Tütüncü, Melih , Uygunoğlu, Uğur , Şen, Sedat , Weber, Lea, Eryılmaz, Aslı

JAMA Neurology | August 21, 2023 | Volume: 80 | Issue: 10 | Pages: 1080

10.1001/jamaneurol.2023.2815 Get It

Importance Radiologically isolated syndrome (RIS) represents the earliest detectable preclinical phase of multiple sclerosis (MS) punctuated by incidental magnetic resonance imaging (MRI) white matter anomalies within the central nervous system. Objective To determine the time to onset of symptoms consistent with MS. Design, Setting, and Participants From September 2017 to October 2022, this multicenter, double-blind, phase 3, randomized clinical trial investigated the efficacy of teriflunomide in delaying MS in individuals with RIS, with a 3-year follow-up. The setting included referral centers in France, Switzerland, and Turkey. Participants older than 18 years meeting 2009 RIS criteria were randomly assigned (1:1) to oral teriflunomide, 14 mg daily, or placebo up to week 96 or, optionally, to week 144. Interventions Clinical, MRI, and patient-reported outcomes (PROs) were collected at baseline and yearly until week 96, with an optional third year in the allocated arm if no symptoms have occurred. Main outcomes Primary analysis was performed in the intention-to-treat population, and safety was assessed accordingly. Secondary end points included MRI outcomes and PROs. Results Among 124 individuals assessed for eligibility, 35 were excluded for declining to participate, not meeting inclusion criteria, or loss of follow-up. Eighty-nine participants (mean [SD] age, 37.8 [12.1] years; 63 female [70.8%]) were enrolled (placebo, 45 [50.6%]; teriflunomide, 44 [49.4%]). Eighteen participants (placebo, 9 [50.0%]; teriflunomide, 9 [50.0%]) discontinued the study, resulting in a dropout rate of 20% for adverse events (3 [16.7%]), consent withdrawal (4 [22.2%]), loss to follow-up (5 [27.8%]), voluntary withdrawal (4 [22.2%]), pregnancy (1 [5.6%]), and study termination (1 [5.6%]). The time to the first clinical event was significantly extended in the teriflunomide arm compared with placebo, in both the unadjusted (hazard ratio [HR], 0.37; 95% CI, 0.16-0.84; P = .02) and adjusted (HR, 0.28; 95% CI, 0.11-0.71; P = .007) analysis. Secondary imaging end point outcomes including the comparison of the cumulative number of new or newly enlarging T2 lesions (rate ratio [RR], 0.57; 95% CI, 0.27-1.20; P = .14), new gadolinium-enhancing lesions (RR, 0.33; 95% CI, 0.09-1.17; P = .09), and the proportion of participants with new lesions (odds ratio, 0.72; 95% CI, 0.25-2.06; P = .54) were not significant. Conclusion and Relevance Treatment with teriflunomide resulted in an unadjusted risk reduction of 63% and an adjusted risk reduction of 72%, relative to placebo, in preventing a first clinical demyelinating event. These data suggest a benefit to early treatment in the MS disease spectrum. Trial Registration ClinicalTrials.gov Identifier: NCT03122652
Impact of COVID-19 vaccination or infection on disease activity in a radiologically isolated syndrome cohort: The VaxiRIS study
Cohen, Mikaël , Thomel-Rocchi, Océane, Sıva, Aksel , Okuda, Darin T. , Karabudak, Rana , Terzi, Murat , Carra‐Dallière, Clarisse , Durand‐Dubief, Françoise , Thouvenot, Éric , Ciron, Jonathan , Bourre, Bertrand , Casez, Olivier , Moreau, Thibault, Neau, Jean‐Philippe, Pelletier, Daniel , Kantarci, Orhun H. , Tütüncü, Melih , Derache, Nathalie, Bensa, Caroline , Louapre, Céline , Benoit, Jeanne , Landes-Château, Cassandre , Carra Dallière, Clarisse , Thouvenot, Eric , Ciron, Jonathan , Lebrun‐Frénay, Christine , Siva, Aksel , Durand-Dubief, Françoise , Okuda, Darin T , Cohen, Mikaël , Efendi, Hüsnü , Zéphir, Hélène , Bourre, Bertrand , Casez, Olivier , Seze, Jerome De

Multiple Sclerosis Journal | June 16, 2023 | Volume: 29 | Issue: 9 | Pages: 1099-1106

10.1177/13524585231179669 Get It

Background: Vaccination in patients with multiple sclerosis (MS) treated with immunosuppressive drugs is highly recommended. Regarding COVID-19 vaccination, no specific concern has been raised. Objectives: We aimed to evaluate if COVID-19 vaccination or infection increased the risk of disease activity, either radiological or clinical, with conversion to MS in a cohort of people with a radiologically isolated syndrome (RIS). Methods: This multicentric observational study analyzed patients in the RIS Consortium cohort during the pandemic between January 2020 and December 2022. We compared the occurrence of disease activity in patients according to their vaccination status. The same analysis was conducted by comparing patients’ history of COVID-19 infection. Results: No difference was found concerning clinical conversion to MS in the vaccinated versus unvaccinated group (6.7% vs 8.5%, p > 0.9). The rate of disease activity was not statistically different (13.6% and 7.4%, respectively, p = 0.54). The clinical conversion rate to MS was not significantly different in patients with a documented COVID-19 infection versus non-infected patients. Conclusion: Our study suggests that COVID-19 infection or immunization in RIS individuals does not increase the risk of disease activity. Our results support that COVID-19 vaccination can be safely proposed and repeated for these subjects.
Reply: Do we need new MRI criteria for the diagnosis of radiologically isolated syndrome?
Lebrun‐Frénay, Christine , Kantarci, Orhun H. , Sıva, Aksel , Pelletier, Daniel , Lebrun‐Frénay, Christine , Siva, Aksel , Okuda, Darin T.

Brain | May 31, 2023 | Volume: 146 | Issue: 11 | Pages: e104-e106

10.1093/brain/awad186 Get It

The radiologically isolated syndrome: revised diagnostic criteria
Lebrun‐Frénay, Christine , Okuda, Darin T. , Sıva, Aksel , Landes-Château, Cassandre , Azevedo, Christina , Mondot, Lydiane , Louapre, Céline , Durand‐Dubief, Françoise , Page, Emmanuelle Le , Bensa, Caroline , Ciron, Jonathan , Casez, Olivier , Mathey, Guillaume , Zeydan, Burcu , Makhani, Naila , Tütüncü, Melih , Levraut, Michaël , Thouvenot, Éric , Pelletier, Daniel , Kantarci, Orhun H. , Zeydan, Burcu , Lebrun‐Frénay, Christine , Siva, Aksel , Thouvenot, Eric , Ciron, Jonathan , Durand-Dubief, Françoise , Okuda, Darin T , Mondot, Lydiane , Carra‐Dallière, Clarisse , Zéphir, Hélène , Bensa, Caroline , Ruet, Aurélie , Laplaud, David , Casez, Olivier , Seze, Jerome De , Cohen, Mikaël

Brain | March 3, 2023 | Volume: 146 | Issue: 8 | Pages: 3431-3443

10.1093/brain/awad073 Get It

Abstract The radiologically isolated syndrome (RIS) was defined in 2009 as the presence of asymptomatic, incidentally identified demyelinating-appearing white matter lesions in the CNS within individuals lacking symptoms typical of multiple sclerosis (MS). The RIS criteria have been validated and predict the transition to symptomatic MS reliably. The performance of RIS criteria that require fewer MRI lesions is unknown. 2009-RIS subjects, by definition, fulfil three to four of four criteria for 2005 dissemination in space (DIS) and subjects fulfilling only one or two lesions in at least one 2017 DIS location were identified within 37 prospective databases. Univariate and multivariate Cox regression models were used to identify predictors of a first clinical event. Performances of different groups were calculated. Seven hundred and forty-seven subjects (72.2% female, mean age 37.7 ± 12.3 years at the index MRI) were included. The mean clinical follow-up time was 46.8 ± 45.4 months. All subjects had focal T2 hyperintensities suggestive of inflammatory demyelination on MRI; 251 (33.6%) fulfilled one or two 2017 DIS criteria (designated as Groups 1 and 2, respectively), and 496 (66.4%) fulfilled three or four 2005 DIS criteria representing 2009-RIS subjects. Group 1 and 2 subjects were younger than the 2009-RIS group and were more likely to develop new T2 lesions over time (P &lt; 0.001). Groups 1 and 2 were similar regarding survival distribution and risk factors for transition to MS. At 5 years, the cumulative probability for a clinical event was 29.0% for Groups 1 and 2 compared to 38.7% for 2009-RIS (P = 0.0241). The presence of spinal cord lesions on the index scan and CSF-restricted oligoclonal bands in Groups 1–2 increased the risk of symptomatic MS evolution at 5 years to 38%, comparable to the risk of development in the 2009-RIS group. The presence of new T2 or gadolinium-enhancing lesions on follow-up scans independently increased the risk of presenting with a clinical event (P &lt; 0.001). The 2009-RIS subjects or Groups 1 and 2 with at least two of the risk factors for a clinical event demonstrated better sensitivity (86.0%), negative predictive value (73.1%), accuracy (59.8%) and area under the curve (60.7%) compared to other criteria studied. This large prospective cohort brings Class I evidence that subjects with fewer lesions than required in the 2009 RIS criteria evolve directly to a first clinical event at a similar rate when additional risk factors are present. Our results provide a rationale for revisions to existing RIS diagnostic criteria.
Dimethyl Fumarate Delays Multiple Sclerosis in Radiologically Isolated Syndrome
Okuda, Darin T. , Kantarci, Orhun H. , Sormani, Maria Pia , Azevedo, Christina , Hua, Le H. , Hotermans, Christophe, Mendoza, Jason P. , Walsh, John, Hehn, Christian von, Vargas, Wendy , Donlon, Stacy, Okai, Annette , Sıva, Aksel , Pelletier, Daniel , Kantarci, OH , Sormani, Maria P , Mendoza, Jason , Stüve, Olaf , Siva, Aksel , Okuda, Darin T , Lebrun‐Frénay, Christine , Bovis, Francesca , Amezcua, Lilyana , Mowry, Ellen M. , Naismith, Robert T. , Pardo, Gabriel , Repovic, Pavle

Annals of Neurology | November 18, 2022 | Volume: 93 | Issue: 3 | Pages: 604-614

10.1002/ana.26555 Get It

Objective The radiologically isolated syndrome (RIS) represents the earliest detectable pre‐clinical phase of multiple sclerosis (MS). This study evaluated the impact of therapeutic intervention in preventing first symptom manifestation at this stage in the disease spectrum. Methods We conducted a multi‐center, randomized, double‐blinded, placebo‐controlled study involving people with RIS. Individuals without clinical symptoms typical of MS but with incidental brain MRI anomalies consistent with central nervous system (CNS) demyelination were included. Within 12 MS centers in the United States, participants were randomly assigned 1:1 to oral dimethyl fumarate (DMF) 240 mg twice daily or placebo. The primary endpoint was the time to onset of clinical symptoms attributable to a CNS demyelinating event within a follow‐up period of 96 weeks. An intention‐to‐treat analysis was applied to all participating individuals in the primary and safety investigations. The study is registered at ClinicalTrials.gov , NCT02739542 (ARISE). Results Participants from 12 centers were recruited from March 9, 2016, to October 31, 2019, with 44 people randomized to dimethyl fumarate and 43 to placebo. Following DMF treatment, the risk of a first clinical demyelinating event during the 96‐week study period was highly reduced in the unadjusted Cox proportional‐hazards regression model (hazard ratio [HR] = 0.18, 95% confidence interval [CI] = 0.05–0.63, p = 0.007). More moderate adverse reactions were present in the DMF (34 [32%]) than placebo groups (19 [21%]) but severe events were similar (DMF, 3 [5%]; placebo, 4 [9%]). Interpretation This is the first randomized clinical trial demonstrating the benefit of a disease‐modifying therapy in preventing a first acute clinical event in people with RIS. ANN NEUROL 2023;93:604–614
The risk of infections for multiple sclerosis and neuromyelitis optica spectrum disorder disease-modifying treatments: Eighth European Committee for Treatment and Research in Multiple Sclerosis Focused Workshop Review. April 2021
Tur, Carmen , Otero‐Romero, Susana , Amato, Maria Pia , Derfuss, Tobias , Pauli, Franziska Di , Abboud, Hesham , Achiron, Anat , Casanova, Jean‐Laurent , Clifford, David B. , Fonderico, Mattia , Gouider, Riadh , Hacohen, Yael , Kappos, Ludwig , Ladeira, Filipa , Louapre, Céline , Magyari, Melinda , Papeix, Caroline , Piehl, Fredrik , Ruíz-Camps, Isabel , Selmaj, Krzysztof , Simpson, Steve , Sıva, Aksel , Vaknin‐Dembinsky, Adi , Weinshenker, Brian G. , Winkelmann, Alexander, Rodas, María Isabel Zuluaga , Tintoré, Mar , Amato, Maria Pia , Derfuss, Tobias , Abboud, Hesham , Achiron, Anat , Dobson, Ruth , Filippi, Massimo , Fitzgerald, Kathryn C , Fonderico, Mattia , Hellwig, Kerstin , Hemmer, Bernhard , Ladeira, Filipa , Lebrun‐Frénay, Christine , Magyari, Melinda , Oreja-Guevara, Celia , Pandit, Lekha , Papeix, Caroline , Portaccio, Emilio , Simpson-Yap, Steve , Siva, Aksel , Sormani, Maria P , Vukusic, Sandra , Wiendl, Heinz , Tintoré, Mar , Weinshenker, Brian G , Casanova, Jean Laurent , Hacohen, Yael , Dubessy, Anne‐Laure , Iacobaeus, Ellen , Mycko, Marcin P. , Bellinvia, Angelo , Boyко, Alexey , Farez, Mauricio , Filippi, Massimo , Mehling, Matthias , Oreja‐Guevara, Celia , Pandit, Lekha , Sørensen, Per Soelberg , Sormani, Maria Pia , Trojano, María , Wiendl, Heinz , Stankoff, Bruno

Multiple Sclerosis Journal | February 24, 2022 | Volume: 28 | Issue: 9 | Pages: 1424-1456

10.1177/13524585211069068 Get It

Over the recent years, the treatment of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) has evolved very rapidly and a large number of disease-modifying treatments (DMTs) are now available. However, most DMTs are associated with adverse events, the most frequent of which being infections. Consideration of all DMT-associated risks facilitates development of risk mitigation strategies. An international focused workshop with expert-led discussions was sponsored by the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) and was held in April 2021 to review our current knowledge about the risk of infections associated with the use of DMTs for people with MS and NMOSD and corresponding risk mitigation strategies. The workshop addressed DMT-associated infections in specific populations, such as children and pregnant women with MS, or people with MS who have other comorbidities or live in regions with an exceptionally high infection burden. Finally, we reviewed the topic of DMT-associated infectious risks in the context of the current SARS-CoV-2 pandemic. Herein, we summarize available evidence and identify gaps in knowledge which justify further research.