Delimitation of the risk area of the vertebral artery during the paramedian suboccipital approach.

OBJECTIVE: The V3 segment of the vertebral artery (V3-VA) is at risk during diverse approaches to the craniovertebral junction. Our objective is to present a system of anatomic and topographic landmarks to identify the V3-VA during the paramedian suboccipital approach (PMSOA) with the help of minimal or basic tools. MATERIAL AND METHODS: The first was a retrospective analysis of the angiotomography (CTA) of 50 patients over 18-years old, and 9 anatomical dissections. A series of lines were defined between the different bony landmarks. Within this lines the risk area of the vertebral artery (RAsV3-VA) and the risk point of the vertebral artery (RPsV3-VA) were defined. The second stage was a prospective study, where the previously defined measurements were carried out by using neuronavigation in 10 patients (20 sides) operated with the PMSO approach in order to confirm the presence of the V3 segment in the RAsV3-VA and RPsV3-VA. RESULTS: In the first stage, the V3 segment was found in the middle third of the X line in 96,6% of the cases. The distance between the inion and the UCP (percentile 5) was 20 mm and to the LCP (percentile 95) was 40 mm. In the range between the UCP and the LCP, in the middle third of the inion-mastoid line (RAsV3-VA), we found 90% of the V3-VA. The measurements taken during the second stage revealed that the artery was in the middle third of the X line in 97% of the cases. 85% of the patients presented the total of the V3s-VA on the RAsV3-VA and in 85% there was a direct relationship with the V3 segment and the RPV3s-VA. CONCLUSION: We propose an easy-to-implement system to delimit the risk area of the V3-VA during the PMSOA. We believe that these landmarks provide a practical, reliable, costless and useful tool that could decrease the risk of lesion of the V3-VA during this approach without the need of using.

MRI pattern in acute optic neuritis: Comparing multiple sclerosis, NMO and MOGAD.

BACKGROUND: Several MRI findings of optic neuritis (ON) have been described and correlated with specific underlying etiologies. Specifically, optic nerve enhancement is considered an accurate biomarker of acute ON. OBJECTIVE: To identify differences in MRI patterns of optic nerve enhancement in certain demyelinating etiologies presenting with acute ON. METHODS: Retrospective analysis of enhancement patterns on fat-suppressed T1-weighted images from patients presenting clinical and radiological acute ON, treated at our institution between January 2014 and June 2022. Location and extension of enhancing optic nerve segments, as well as presence of perineural enhancement were evaluated in three predetermined demyelinating conditions. Fisher's exact test and chi2 were calculated. RESULTS: Fifty-six subjects met eligibility criteria. Mean age was 31 years (range 6-79) and 70% were females. Thirty-four (61%) patients were diagnosed with multiple sclerosis (MS), 8 (14%) with neuromyelitis optica (NMO), and 14 (25%) with anti-myelin oligodendrocyte glycoprotein disease (MOGAD). Bilateral involvement was more frequent in MOGAD, compared to MS and NMO (43 vs 3% and 12.5% respectively, p = 0.002). MS patients showed shorter optic nerve involvement, whereas MOGAD showed more extensive lesions (p = 0.006). Site of involvement was intraorbital in 63% MS, 89% NMO, 90% MOGAD (p = 0.051) and canalicular in 43% MS, 33% NMO and 75% MOGAD (p = 0.039). Intracranial or chiasmatic involvement and presence of perineural enhancement were not statistically different between entities. CONCLUSION: In the setting of acute ON, patients presenting MOGAD were more likely to show bilateral, longitudinally extended and anterior (intraorbital and canalicular) optic nerve involvement compared to patients with MS or NMO.

Predictive factors for the development of epilepsy after ischemic stroke.

OBJECTIVES: Ischemic stroke is one of the most common causes of epilepsy in adults. The incidence of post-stroke epilepsy (PSE) is approximately 7%. Risk factors are higher stroke severity, cortical localization, higher National Institute of Health Stroke Scale (NIHSS) upon admission and acute symptomatic seizures. We analyzed the predictive factors of PSE development in our population. MATERIALS AND METHODS: Retrospective observational cohort of adult patients (age ≥ 18 years) with ischemic stroke assessed between January 2012 and June 2020. Patients with personal history of epilepsy and potentially epileptogenic structural injury other than acute or chronic stroke were excluded. Demographic, clinical and imaging variables were evaluated in a multivariate analysis for independent risk factors associated with PSE. RESULTS: Medical records of 1586 stroke patients were reviewed, 691 met the inclusion criteria and had at least one year of follow-up. Of them, 428 (61.9%) were males. During follow-up, 6.2% had diagnosis of PSE (42/691) with a higher frequency of: previous ischemic stroke, higher NIHSS upon admission, treatment with rt-PA, higher Fazekas scale grade, cortical involvement, hemorrhagic transformation, acute symptomatic seizures, longer hospitalization and higher modified Rankin Scale (mRS) at discharge compared to the group without PSE. In a multivariate analysis, acute symptomatic seizures (OR=3.22, p: 0.033), cortical involvement (OR=0.274, p < 0.05), Fazekas scale score (OR=0.519, p < 0.05) and mRS at discharge (OR=1.33, p: 0.043) were independent risk factors. CONCLUSIONS: The variables related to higher risk of PSE were similar to those reported in the literature, highlighting the importance of neuroimaging findings, acute symptomatic seizures during hospitalization and neurological deficit at discharge. The data obtained will serve as the basis for construction of predictive models, allowing to individualize PSE probability in our population.

Biomarcadores radiológicos en RM para una aproximación al diagnóstico molecular en gliomas IDH-mutados (grado II y III) / MR Imaging Biomarkers for a Diagnostic Approach of IDH-mutated Gliomas (Grades II/III)

Resumen Objetivo: Analizar características por resonancia magnética (RM) de gliomas IDH-mutados (grado II y III) en base a parámetros cualitativos, a fin de valorar el rendimiento del signo del mismatch T2-FLAIR y otras características morfológicas de los tumores, en predecir el estado del 1p/19q y su reproducibilidad interobservador. Métodos Estudio retrospectivo, descriptivo y analítico sobre una cohorte de 53 gliomas IDH-mutados (grado II y III) y molecularmente definidos respecto al 1p/19q, seleccionados a partir de la base de datos de la institución, durante el periodo 2014- 2019. Dos neuroradiólogos evaluaron características imagenológicas de forma independiente y enmascarada al diagnóstico: mismatch T2-FLAIR, localización tumoral, bordes, señal, infiltración cortical e inhomogeneidad en T2. Los casos discordantes fueron evaluados por un tercer neuroradiólogo de mayor experiencia. Resultados: Treinta de 53 (56,6%) gliomas fueron no codelecionados, y 23/53 (43,4%) codelecionados. El signo del mismatch T2-FLAIR fue positivo en 16/53 (30,18%) pacientes, 15/16 (93,75%) no codelecionados y 1/16 (6,25%) codelecionado (Exacto de Fisher p = <,0001). Los dos evaluadores demostraron una concordancia interobservador casi perfecta para ese signo, κ =,907 (95% CI, 0,781 a 1,0). La especificidad y el valor predictivo positivo del signo para predecir la ausencia de la codeleción fue de un 95,7% y un 93,8% respectivamente. Discusión: La reciente actualización en la clasificación de los gliomas los clasifica acorde a su perfil molecular. En los últimos años, varios investigadores han estudiado características morfológicas por RM de los tumores con la intención de predecir las características moleculares de los mismos. Conclusión: En nuestra población, el signo del mismatch T2-FLAIR es el único biomarcador radiológico que muestra asociación estadísticamente significativa en predecir la ausencia de codeleción en los gliomas IDH-mutados (grado II y III), con una alta especificidad y un alto valor predictivo positivo.

Abstract Objective: To analyze magnetic resonance (MR) characteristics of IDH-mutated gliomas (grades II/III) utilizing qualitative parameters with the goal of assessing the performance of the T2-FLAIR mismatch sign and other morphological characteristics of tumors in predicting the 1p/19q co-deletion status as well as inter-observer reproducibility. Methods: Retrospective and descriptive study analyzing a cohort of 53 IDH-mutated lower-grade (grades II/III) gliomas with known 1p/19q co-deletion status. Patients meeting selection criteria for this study were taken from our institutional data from 2014-2019. Two neuroradiologists assessed the following imaging characteristics independently, and blinded from the diagnosis: T2-FLAIR mismatch, tumor location, borders, signal characteristics, cortical infiltration and T2* inhomogeneity. In the event of discordant interpretations, a third senior neuroradiologist also evaluated the case. Results: 23 of the 53 (43.4%) gliomas demonstrated 1p/19q co-deletion and 30 of 53 (56.6%) did not. T2-FLAIR mismatch was positive in 16 of 53 cases (30.2%) with 15 of 16 (93.8%) demonstrating no co-deletion and 1/16 (6.25%) with co-deletion (Fisher's exact p = < .0001). The two readers showed an almost perfect interreader agreement for this sign κ = 0.907 (95% CI, 0.781 to 1.0). Specificity and positive predictive value of the sign to predict the absence of co-deletion was 95.7% and 93.8% respectively. Discussion: The recent update in classification of lower-grade gliomas segregates gliomas according to molecular profile. In the recent past, many researchers have studied MR morphologic characteristics of these tumors with the intention of predicting molecular features of said tumors Conclusion: In our patient population, T2-FLAIR mismatch sign is the only radiologic biomarker that shows statistically significant association with the absence of 1p/19q co-deletion in lower-grade gliomas, with high specificity and positive predictive value.