Dentate nucleus: a review and implications for dentatotomy.

PURPOSE: The dentate nucleus (DN) is the largest, most lateral, and phylogenetically most recent of the deep cerebellar nuclei. Its pivotal role encompasses the planning, initiation, and modification of voluntary movement but also spans non-motor functions like executive functioning, visuospatial processing, and linguistic abilities. This review aims to offer a comprehensive description of the DN, detailing its embryology, anatomy, physiology, and clinical relevance, alongside an analysis of dentatotomy. METHODS AND RESULTS: We delve into the history, embryology, anatomy, vascular supply, imaging characteristics, and clinical significance of the DN. Furthermore, we thoroughly review the dentatotomy, emphasizing its role in treating spasticity. CONCLUSIONS: Understanding the intricacies of the anatomy, physiology, vasculature, and projections of the DN has taken on increased importance in current neurosurgical practice. Advances in technology have unveiled previously unknown functions of the deep cerebellar nuclei, predominantly related to non-motor domains. Such discoveries are revitalizing older techniques, like dentatotomy, and applying them to newer, more localized targets.

Comparison of microvascular decompression, percutaneous radiofrequency rhizotomy, and stereotactic radiosurgery in the treatment of trigeminal neuralgia: A long term quasi-experimental study.

BACKGROUND: Microvascular decompression (MVD), radiofrequency rhizotomy (RFR), and stereotactic radiosurgery (SRS) are surgical techniques frequently used in the treatment of idiopathic trigeminal neuralgia (TN), although the results reported for each of these are diverse. OBJECTIVE: This study aimed to compare long-term pain control obtained by MVD, SRS, and RFR in patients with idiopathic TN. METHODS: To compare the results obtained by MVD, SRS, and RFR we chose a quasi-experimental, ambispective design with control groups but no pretest. A total of 52 participants (MVD n = 33, RFR n = 10, SRS n = 9) were included. Using standardized outcome measures, pain intensity, pain relief, quality of life, and satisfaction with treatment were assessed by an independent investigator. The TREND statement for reporting non-randomized evaluations was applied. Clinical outcomes were evaluated at the initial postoperative period and at 6 months, 1, 2, 3, 4, and 5 years postoperatively. RESULTS: MVD has shown better results in pain scales compared to ablative procedures. Significant differences between groups were found regarding pain intensity and pain relief at the initial postoperative period (p < 0.001) and 6 months (p = 0.022), 1 year (p < 0.001), 2 years (p = 0.002), and 3 years (p = 0.004) after the intervention. Those differences exceeded the thresholds of the minimal clinically important difference. A higher percentage of patients free of pain was observed in the group of patients treated by MVD, with significant differences at the initial postoperative period (p < 0.001) and 6 months (p = 0.02), 1 year (p = 0.001), and 2 years (p = 0.04) after the procedure. Also, a higher risk of pain recurrence was observed in the RFR and SRS groups (HR 3.15, 95% CI 1.33-7.46; p = 0.009; and HR 4.26, 95% CI 1.77-10.2; p = 0.001, respectively) compared to the MVD group. No significant differences were found in terms of quality of life and satisfaction with treatment. A higher incidence of complications was observed in the MVD group. CONCLUSION: Concerning pain control and risk of pain recurrence, MVD is superior to RFR and SRS, but not in terms of quality of life, satisfaction with treatment, and safety profile.

WHO CNS5 2021 includes specific mutations in gliomas that can be identified with MRI quantitative biomarkers.

In 2021, the latest version of the World Health Organization classification of central nervous system tumors (WHO CNS5) was published, which is considered an international standard. The first editions of this classification were based on histological characteristics and, subsequently, aspects related to new knowledge were incorporated. In the 2016 revision, molecular characteristics were implemented for the classification and staging of gliomas, such as the presence of mutations in IDH1 or IDH2. Currently, advanced magnetic resonance imaging (MRI) techniques allow assessing for the presence of 2-HG (increased oncometabolite that precedes IDH mutations), whereby IDH mutations can be indirectly identified, without invasive procedures being required. Advanced MRI is a growing field, highly useful for diagnosis and management of different pathologies. This document addresses the implications of WHO CNS5 classification in the evaluation of gliomas, as well as historical aspects, the bases of conventional MRI, and advanced MRI sequences useful in current classification.

En 2021 se publicó la última versión de la clasificación de tumores del sistema nervioso central de la Organización Mundial de la Salud (WHO CNS5 por sus siglas en inglés), considerada un estándar internacional. Las primeras ediciones se basaron en características histológicas y posteriormente se incorporaron aspectos relacionados con nuevos conocimientos. En la revisión de 2016 se implementaron características moleculares para la clasificación y estadificación de los gliomas, como la presencia de mutaciones en IDH1 y IDH2. Actualmente, las técnicas de resonancia magnética avanzada permiten valorar la presencia de 2-HG (oncometabolito incrementado ante mutaciones en IDH), de forma que indirectamente y sin procedimientos invasivos pueden identificarse las mutaciones en IDH. La resonancia magnética avanzada es un procedimiento aún en desarrollo, de gran utilidad para el diagnóstico y manejo de distintas patologías. En el presente documento se abordan las implicaciones de la WHO CNS5 en la evaluación de gliomas, así como aspectos históricos, las bases de la resonancia magnética convencional y secuencias de resonancia magnética avanzada útiles en la clasificación actual.

The Genomic Landscape of Corticotroph Tumors: From Silent Adenomas to ACTH-Secreting Carcinomas.

Corticotroph cells give rise to aggressive and rare pituitary neoplasms comprising ACTH-producing adenomas resulting in Cushing disease (CD), clinically silent ACTH adenomas (SCA), Crooke cell adenomas (CCA) and ACTH-producing carcinomas (CA). The molecular pathogenesis of these tumors is still poorly understood. To better understand the genomic landscape of all the lesions of the corticotroph lineage, we sequenced the whole exome of three SCA, one CCA, four ACTH-secreting PA causing CD, one corticotrophinoma occurring in a CD patient who developed Nelson syndrome after adrenalectomy and one patient with an ACTH-producing CA. The ACTH-producing CA was the lesion with the highest number of single nucleotide variants (SNV) in genes such as USP8, TP53, AURKA, EGFR, HSD3B1 and CDKN1A. The USP8 variant was found only in the ACTH-CA and in the corticotrophinoma occurring in a patient with Nelson syndrome. In CCA, SNV in TP53, EGFR, HSD3B1 and CDKN1A SNV were present. HSD3B1 and CDKN1A SNVs were present in all three SCA, whereas in two of these tumors SNV in TP53, AURKA and EGFR were found. None of the analyzed tumors showed SNV in USP48, BRAF, BRG1 or CABLES1. The amplification of 17q12 was found in all tumors, except for the ACTH-producing carcinoma. The four clinically functioning ACTH adenomas and the ACTH-CA shared the amplification of 10q11.22 and showed more copy-number variation (CNV) gains and single-nucleotide variations than the nonfunctioning tumors.

Glioblastoma Treatment: State-of-the-Art and Future Perspectives.

(1) Background: Glioblastoma is the most frequent and lethal primary tumor of the central nervous system. Through many years, research has brought various advances in glioblastoma treatment. At this time, glioblastoma management is based on maximal safe surgical resection, radiotherapy, and chemotherapy with temozolomide. Recently, bevacizumab has been added to the treatment arsenal for the recurrent scenario. Nevertheless, patients with glioblastoma still have a poor prognosis. Therefore, many efforts are being made in different clinical research areas to find a new alternative to improve overall survival, free-progression survival, and life quality in glioblastoma patients. (2) Methods: Our objective is to recap the actual state-of-the-art in glioblastoma treatment, resume the actual research and future perspectives on immunotherapy, as well as the new synthetic molecules and natural compounds that represent potential future therapies at preclinical stages. (3) Conclusions: Despite the great efforts in therapeutic research, glioblastoma management has suffered minimal changes, and the prognosis remains poor. Combined therapeutic strategies and delivery methods, including immunotherapy, synthetic molecules, natural compounds, and glioblastoma stem cell inhibition, may potentiate the standard of care therapy and represent the next step in glioblastoma management research.

Diffusion tensor imaging-derived biomarkers performance in glioblastoma tumor regions: exploratory data analysis using zombie plots and diagnostic tests.

INTRODUCTION: Using diffusion tensor imaging (DTI), 11 biomarkers have been reported in different glioblastoma (GB) regions. OBJECTIVE: To compare the efficacy of GB biomarkers using "zombie plots". METHODS: Retrospective cohort of 29 subjects with GB who underwent 3-Tesla brain magnetic resonance imaging. DTI major, intermediate and minor eigenvalues were used to calculate biomarkers at five tumor regions: normal-appearing white matter (NAWM), proximal and distal edema, tumor tissue and necrosis. Contingency tables with true and false positive and negative results allowed the calculation of zombie plots based on the Bayes factor and previously unreported diagnostic tests. RESULTS: The MD, FA, q, L, Cl, Cp and RA biomarkers had a good performance at the optimal zone for NAWM diagnosis. The proximal and distal edema, enhancing rim and necrosis regions do not have biomarkers that identify them with an optimal performance level. CONCLUSIONS: Zombie plots allow simultaneous comparison of biomarkers based on likelihood ratios. MD, FA, q, L, Cl, Cp, RA discriminated NAWM normal brain tissue at the optimal zone, but performance for other regions was at the mediocre, diagnostic inclusion and diagnostic exclusion zones.

INTRODUCCIÓN: Han sido reportados 11 biomarcadores de imágenes con tensor de difusión (DTI) en las regiones tumorales del glioblastoma. OBJETIVO: Comparar la eficacia de biomarcadores de glioblastoma mediante gráficos de zombie, que permiten la comparación simultánea en función de razones de verosimilitud. MÉTODOS: Cohorte retrospectiva de 29 sujetos con glioblastoma a quienes se efectuó resonancia magnética cerebral de 3 T. Los eigenvalores mayor, intermedio y menor de ITD se utilizaron para calcular 11 biomarcadores en cinco regiones tumorales: sustancia blanca de apariencia normal (NAWM), edema proximal y distal, tumoral viable y necrosis. Las tablas de contingencia con resultados verdaderos y falsos positivos y negativos permitieron calcular gráficos de zombie basados en el factor de Bayes y pruebas diagnósticas previamente no reportadas. RESULTADOS: Los biomarcadores DM, AF, q, L, Cl, Cp, AR actúan en la zona óptima para el diagnóstico de NAWM. Las regiones de edema proximal y distal, tejido tumoral que se realza con contraste y necrosis no poseen biomarcadores que las identifiquen en un nivel de rendimiento óptimo. CONCLUSIONES: Los biomarcadores DM, AF, q, L, Cl, Cp, AR discriminan el tejido cerebral normal en la zona óptima, pero el rendimiento de otras regiones tumorales se ubica en las zonas de inclusión diagnóstica, exclusión diagnóstica y mediocre.

Malignant Glioma Therapy by Vaccination with Irradiated C6 Cell-Derived Microvesicles Promotes an Antitumoral Immune Response.

Glioblastoma is the most common and malignant tumor of the CNS, with a mean survival of 14 months after diagnosis. Its unfavorable prognosis reveals the need for novel therapies. It is known that radiation can induce a systemic antitumor effect. Tumor cells produce and release microvesicles in response to cell damage such as radiation. Microvesicles contain a plethora of bioactive molecules, including antigens involved in modulation of the immune response. In this study, we characterized and evaluated irradiated C6 cell-derived microvesicles as a therapeutic vaccination in C6 malignant glioma. Cultured C6 glioma cells were irradiated with a single dose of 50 Gy to obtain the microvesicles. Subcutaneous implantation of C6 cells was performed when the tumor reached 2 cm in diameter, and non-irradiated and irradiated C6 cell-derived microvesicles were administered subcutaneously. Tumor growth, apoptosis, and immunophenotypes were determined. Reduction of tumor volume (more than 50%) was observed in the group treated with irradiated C6 cell-derived microvesicles compared with the control (p = 0.03). The percentages of infiltrative helper, cytotoxic, and regulatory T lymphocytes as well as apoptotic cells were increased in tumors from immunized rats compared with controls. These findings make microvesicle-based vaccination a promising immunotherapeutic approach against glioblastoma.

Fractal anatomy of the hippocampal formation.

PURPOSE: We believed that the hippocampal complex is a fractal, and we try to demonstrate it. METHODS: We selected 12 magnetic resonance (MR) studies from healthy brains. Five women and 7 men without neurological or psychiatric disease were analyzed. The age range was 50-71 years old, with a mean 57.1 ± 7.6 years. Image series of MR were obtained through 3D SPGR in scanner GE Singa 3.0 T (general Electric, USA), matrix acquisition 512 Å-512 Å-120, field size 240 mm, voxel size 0.47 mm Å-0.47 mm Å-1.2 mm, repetition time of 13 ms and eco time of 5.6 ms. The MRI were imported in DICOM format in the OsiriXsoftware where they were contoured. Post processing was done with ImageJ software; Box Counting method for fractal analysis and we also used the Box Counting method of the BoneJ plugin. RESULTS: All of the hippocampus analyzed were a fractal. The fractal dimension analysis distribution of the measurements had a central tendency. The mean of hippocampal fractal dimension was 1.32635, the range was from 1.3373 to 1.5344. We found a short interval of variability in the hippocampal fractal number. CONCLUSIONS: The hippocampal complex is a fractal. The fractal analysis must be an objective measurement that can help us as a descriptive tool in hippocampal anatomy and maybe in a close future in the diagnosis of anatomical alterations.

RB mutation and RAS overexpression induce resistance to NK cell-mediated cytotoxicity in glioma cells.

Several theories aim to explain the malignant transformation of cells, including the mutation of tumor suppressors and proto-oncogenes. Deletion of Rb (a tumor suppressor), overexpression of mutated Ras (a proto-oncogene), or both, are sufficient for in vitro gliomagenesis, and these genetic traits are associated with their proliferative capacity. An emerging hallmark of cancer is the ability of tumor cells to evade the immune system. Whether specific mutations are related with this, remains to be analyzed. To address this issue, three transformed glioma cell lines were obtained (Rb(-/-), Ras(V12), and Rb(-/-)/Ras(V12)) by in vitro retroviral transformation of astrocytes, as previously reported. In addition, Ras(V12) and Rb(-/-)/Ras(V12) transformed cells were injected into SCID mice and after tumor growth two stable glioma cell lines were derived. All these cells were characterized in terms of Rb and Ras gene expression, morphology, proliferative capacity, expression of MHC I, Rae1δ, and Rae1αßγδε, mult1, H60a, H60b, H60c, as ligands for NK cell receptors, and their susceptibility to NK cell-mediated cytotoxicity. Our results show that transformation of astrocytes (Rb loss, Ras overexpression, or both) induced phenotypical and functional changes associated with resistance to NK cell-mediated cytotoxicity. Moreover, the transfer of cell lines of transformed astrocytes into SCID mice increased resistance to NK cell-mediated cytotoxicity, thus suggesting that specific changes in a tumor suppressor (Rb) and a proto-oncogene (Ras) are enough to confer resistance to NK cell-mediated cytotoxicity in glioma cells and therefore provide some insight into the ability of tumor cells to evade immune responses.

Varias teorías pretenden explicar la transformación maligna de las células, como es la mutación de genes supresores de tumor y proto-oncogenes. La deleción de Rb (un supresor de tumor), la sobreexpresión de Ras mutado (un proto-oncogén), o ambos, son suficientes para desarrollar gliomagénesis in vitro, y estas características genéticas se asocian con su alta tasa de proliferación. Un rasgo distintivo del cáncer es la capacidad de las células tumorales para evadir el sistema inmune. Por lo que en este estudio analizamos si las mutaciones específicas están relacionadas con la evasión de la respuesta inmune. Para abordar esta cuestión, tres líneas celulares de glioma transformadas se obtuvieron (Rb−/−, RasV12, y Rb−/−/RasV12) mediante transformación retroviral de astrocitos in vitro, reportado anteriormente. Además, las células transformadas RasV12 y Rb−/−/RasV12 fueron inyectadas en ratones SCID y después del crecimiento del tumor se obtuvieron dos líneas celulares de glioma estables. En todas las células se determinaron la expresión génica Rb y Ras, morfología, capacidad de proliferación, expresión de MHC I, Rae1δ, and Rae1αßγδε, mult1, H60a, H60b, H60c, como ligandos para receptores de células NK, y su susceptibilidad a la citotoxicidad mediada por células NK. Nuestros resultados muestran que la transformación de los astrocitos (pérdida de Rb, la sobreexpresión de Ras, o ambos) indujo cambios fenotípicos y funcionales asociados con la resistencia a la citotoxicidad mediada por células NK. Además, la transferencia de astrocitos transformados dentro de ratones SCID aumento la resistencia a la citotoxicidad mediada por células NK, lo que se sugiere que los cambios específicos en un supresor de tumores (Rb) y un proto-oncogén (Ras) son suficientes para conferir resistencia a la citotoxicidad mediada por células NK en células de glioma y, por tanto, proporcionar una idea de la capacidad de las células tumorales para evadir la respuesta inmune.

[First Mexican consensus on recommendations of the multidisciplinary care of patients with glioblastoma multiforme (GBM): Mexican Interdisciplinary Group on Neuro-Oncology Research (GIMINO)]. / Primer consenso mexicano sobre recomendaciones de la atención multidisciplinaria del paciente con glioblastoma multiforme (GBM). Grupo Interdisciplinar Mexicano de Investigación en Neurooncología (GIMINO).

Glioblastoma multiforme is one of the most aggressive central nervous system tumors and with worse prognosis. Until now,treatments have managed to significantly increase the survival of these patients, depending on age, cognitive status, and autonomy of the individuals themselves. Based on these parameters, both initial or recurrence treatments are performed, as well as monitoring of disease by imaging studies. When the patient enters the terminal phase and curative treatments are suspended, respect for the previous wishes of the patient and development and implementation of palliative therapies must be guaranteed.

Global diffusion tensor imaging derived metrics differentiate glioblastoma multiforme vs. normal brains by using discriminant analysis: introduction of a novel whole-brain approach.

BACKGROUND: Histological behavior of glioblastoma multiforme suggests it would benefit more from a global rather than regional evaluation. A global (whole-brain) calculation of diffusion tensor imaging (DTI) derived tensor metrics offers a valid method to detect the integrity of white matter structures without missing infiltrated brain areas not seen in conventional sequences. In this study we calculated a predictive model of brain infiltration in patients with glioblastoma using global tensor metrics. METHODS: Retrospective, case and control study; 11 global DTI-derived tensor metrics were calculated in 27 patients with glioblastoma multiforme and 34 controls: mean diffusivity, fractional anisotropy, pure isotropic diffusion, pure anisotropic diffusion, the total magnitude of the diffusion tensor, linear tensor, planar tensor, spherical tensor, relative anisotropy, axial diffusivity and radial diffusivity. The multivariate discriminant analysis of these variables (including age) with a diagnostic test evaluation was performed. RESULTS: The simultaneous analysis of 732 measures from 12 continuous variables in 61 subjects revealed one discriminant model that significantly differentiated normal brains and brains with glioblastoma: Wilks' λ = 0.324, χ(2) (3) = 38.907, p < .001. The overall predictive accuracy was 92.7%. CONCLUSIONS: We present a phase II study introducing a novel global approach using DTI-derived biomarkers of brain impairment. The final predictive model selected only three metrics: axial diffusivity, spherical tensor and linear tensor. These metrics might be clinically applied for diagnosis, follow-up, and the study of other neurological diseases.

Stem Cell Markers in Neoplasms and their Relationship with Progression-free and Overall Survival in Patients with Recurrence.

BACKGROUND: Gliomas account for 30% of primary brain tumors in adults, and despite the scientific progress in the field, recurrence is prevalent. Glioma Stem Cells (GSCs) can generate tumor cells in vivo and in vitro and they are associated with treatment resistance, tumor progression, and recurrence. Furthermore, the expression of SOX transcription factors (SOX1, SOX2, SOX9) in these cells is responsible for maintaining an oncogenic genotype and is associated with an aggressive tumor phenotype. The relationship between SOX transcription factors and their prognostic role in recurrent gliomas has not been described in detail. Therefore, we set out to describe the relationship between SOX expression and Progression-free Survival (PFS) and Overall Survival (OS) in patients with recurrent gliomas. METHODS: In this observational study, we have retrospectively analyzed 69 patients, of which 20 met the inclusion criteria. The clinical, radiological, and histopathological findings have been described, and survival analysis has been performed according to SOX expression for PFS and OS. RESULTS: We found SOX1, SOX2, and SOX9 to show a non-statistically significant trend with increasing histopathological grade, co-expressed with Ki67, a cell proliferation factor. CONCLUSION: There has been found an inversely proportional correlation between the degree of immunopositivity of SOX1 and OS. A higher SOX1 immunopositivity could predict a worse clinical prognosis. There has also been found an interaction between a pluripotent genotype (GSC) and cell proliferation.

Radiation therapy for optic nerve sheath meningiomas: Local control and treatment related visual changes.

Objective: Our primary objective is to evaluate the local control of optic nerve sheath meningiomas (ONSMs) treated with ionizing radiation and related visual changes after treatment. Our secondary objective is to describe the clinical characteristics and perform an analysis of the treatment impact on the functional status of this group of patients. Methods: We present our series of 19 patients treated with ionizing radiation therapy at our radio-neurosurgery unit between 2016 and 2022. The setting, ophthalmological follow-up, morbidity, and survival are analyzed and discussed. Results: Patients were followed up, and the impact of treatment on local disease control, visual alterations of the affected eye, and functional status of the patient were analyzed. The progression-free survival (PFS) median was 60 months (95% CI 50.3-69.6 months). The estimated PFS rates at 48 and 66 months were 100% and 66%, respectively. At diagnosis, nine (47.3%) eyes were in amaurosis and ten (52.6%) with vision. Of the ten patients without amaurosis at the time of diagnosis, three (30%) maintained unchanged visual acuity, and seven (70%) had decreased visual acuity; three of them developed amaurosis during the first year after treatment (p = 0.018). Conclusions: Using ionizing radiation therapy is a successful treatment for the local control of ONSMs. This therapeutic modality can compromise the visual acuity of the affected eye and improve dyschromatopsia and campimetry defects. The life prognosis is good for these patients, with a zero mortality rate, but their vision prognosis is poor.

Diagnostic Algorithm for Intracranial Lesions in the Emergency Department: Effectiveness of the Relative Brain Volume and Hounsfield Unit Value Measured by Perfusion Tomography.

Background Early treatment of intracranial lesions in the emergency department is crucial, but it can be challenging to differentiate between them. This differentiation is essential because the treatment of each type of lesion is different. Cerebral computed tomography perfusion (CTP) imaging can help visualize the vascularity of brain lesions and provide absolute quantification of physiological parameters. Compared to magnetic resonance imaging, CTP has several advantages, such as simplicity, wide availability, and reproducibility. Purpose This study aimed to assess the effectiveness of Hounsfield units (HU) in measuring the density of hypercellular lesions and the ability of CTP to quantify hemodynamics in distinguishing intracranial space-occupying lesions. Methods A retrospective study was conducted from March 2016 to March 2022. All patients underwent CTP and CT scans, and relative cerebral blood volume (rCBV) and HU were obtained for intracranial lesions. Results We included a total of 244 patients in our study. This group consisted of 87 (35.7%) individuals with glioblastomas (GBs), 48 (19.7%) with primary central nervous system lymphoma (PCNSL), 45 (18.4%) with metastases (METs), and 64 (26.2) with abscesses. Our study showed that the HUs for METs were higher than those for GB (S 57.4% and E 88.5%). In addition, rCBV values for PCNSL and abscesses were lower than those for GB and METs. The HU in PCNSL was higher than those in abscesses (S 94.1% and E 96.6%). Conclusion PCT parameters provide valuable information for diagnosing brain lesions. A comprehensive assessment improves accuracy. Combining rCBV and HU enhances diagnostic accuracy, making it a valuable tool for distinguishing between lesions. PCT's widespread availability allows for the use of both anatomical and functional information with high spatial resolution for diagnosing and managing brain tumor patients.

Comparison of trigeminal neuralgia radiosurgery plans using two film detectors for the commissioning of small photon beams.

Trigeminal neuralgia (TN) is a chronic, episodic facial pain syndrome that can be extremely intense, and it occurs within the regions of the face that are innervated by the three branches of the trigeminal nerve. Stereotactic radiosurgery (SRS) is the least invasive procedure to treat TN. SRS uses narrow photon beams that require high spatial resolution techniques for their measurement. The use of radiographic or radiochromic films for small-field dosimetry is advantageous because high spatial resolution and two-dimensional dose measurements can be performed. Because these films have different properties, it is expected that the calculated dose distributions for TN patients will behave differently, depending on the detector used for the commissioning of the small photon beams. This work is based on two sets of commissioned data: one commissioned with X-OMAT V2 film and one commissioned with EBT2 film. The calculated dose distributions for 23 TN patients were compared between the commissioning datasets. The variables observed were the differences in the half widths of the 35 and 40 Gy isodose lines (related to the entrance distance to the brainstem) and the volume of the brainstem that received a dose of 12 Gy or more (V12). The results of this comparison showed that there were statistically significant differences between the two calculated dose distributions. The magnitudes of these differences were up to 0.33 mm and 0.38 mm for the 35 and 40 Gy isodose lines. The corresponding difference for the V12 was up to 2.1cc. It is clear that these differences may impact the treatment of TN patients, and then it must be important to perform this type of analysis when observing complication rates. Clinical reports on irradiation techniques for trigeminal neuralgia should consider that different detectors used for commissioning treatment planning systems might result in small but significant differences in dose distributions.

Neurocysticercosis and hydrocephalus: the value of ventriculoperitoneal shunting in its management.

BACKGROUND: Hydrocephalus is the main complication of extraparenchymal neurocysticercosis (EP-NC). Its symptomatic management relies mainly on the placement of a ventriculoperitoneal shunt (VPS). Previous studies have shown that this surgical procedure is associated with a poor prognosis, but current information is lacking. METHODS: We included 108 patients with a definitive diagnosis of EP-NC and hydrocephalus requiring VPS placement. We evaluated their demographic, clinical, and inflammatory characteristics, as well as the frequency of complications related to VPS placement. RESULTS: Hydrocephalus was present at the time of NC diagnosis in 79.6% of patients. VPS dysfunction occurred in 48 patients (44.4%), mainly within the first year after placement (66.7%). The dysfunctions were not associated with the location of the cyst, the inflammatory characteristics of the cerebrospinal fluid or the administration of cysticidal treatment. They were significantly more frequent in patients in whom the decision to place a VPS was made in the emergency department. Two years after VPS, patients' Karnofsky score averaged 84.6±15 and only one patient died of a cause directly related to VPS. CONCLUSIONS: This study confirmed the utility of VPS and showed a significant improvement in the prognosis of patients requiring VPS compared with previous studies.

Diagnostic Performance of Selected MRI-Derived Radiomics Able to Discriminate Progression-Free and Overall Survival in Patients with Midline Glioma and the H3F3AK27M Mutation.

BACKGROUND: Radiomics refers to a recent area of knowledge that studies features extracted from different imaging techniques and subsequently transformed into high-dimensional data that can be associated with biological events. Diffuse midline gliomas (DMG) are one of the most devastating types of cancer, with a median survival of approximately 11 months after diagnosis and 4-5 months after radiological and clinical progression. METHODS: A retrospective study. From a database of 91 patients with DMG, only 12 had the H3.3K27M mutation and brain MRI DICOM files available. Radiomic features were extracted from MRI T1 and T2 sequences using LIFEx software. Statistical analysis included normal distribution tests and the Mann-Whitney U test, ROC analysis, and calculation of cut-off values. RESULTS: A total of 5760 radiomic values were included in the analyses. AUROC demonstrated 13 radiomics with statistical significance for progression-free survival (PFS) and overall survival (OS). Diagnostic performance tests showed nine radiomics with specificity for PFS above 90% and one with a sensitivity of 97.2%. For OS, 3 out of 4 radiomics demonstrated between 80 and 90% sensitivity. CONCLUSIONS: Several radiomic features demonstrated statistical significance and have the potential to further aid DMG diagnostic assessment non-invasively. The most significant radiomics were first- and second-order features with GLCM texture profile, GLZLM_GLNU, and NGLDM_Contrast.

A Survey on Prophylactic Corticosteroids Use in Stereotactic Radiosurgery Treatments From Ibero and Latin America Centers.

Introduction Radiosurgery is a treatment in which a high dose of ionizing radiation is administered to a small field with high-precision techniques, and is a common treatment for tumors and other diagnoses. A typical complication is the development of radiation-induced edema that can progress to radiation necrosis in some cases. The administration of corticosteroids has been used empirically as a prophylaxis in patients who will be treated by stereotactic radiosurgery with intracranial tumors and other pathologies with the intention to prevent radiation-induced edema and or necrosis. Objective The aim of our study is to describe the actual use of corticosteroids in hospitals that perform stereotactic radiosurgery treatments in Latin America and Spain through a survey applied to neurosurgeons and radiation oncologists and expose the implications of the results, as well as to analyze the available literature on it. Methods  We designed a questionnaire of 15 items related to the use of corticosteroids as prophylaxis in patients who will be treated with radiosurgery. The questionnaire was answered by 121 Ibero-Latin Americans through Google Drive considering a database from the Iberolatinoamerican Radiosurgery Association. Results We found that the preference for the use of corticosteroids as prophylaxis for radiosurgery is associated with informal training in radiosurgery, and it was more used by radiation oncologists compared to neurosurgeons (p=0.023). Side effects can exceed the benefit of its use. Conclusions There is practically no literature on the use of corticosteroids as prophylaxis for radiation necrosis in stereotactic radiosurgery. This is a controversial inter- and intra-specialty issue, and its empirical use has a relatively high prevalence, making us reconsider the value of experience in a medical environment that should be fundamentally guided by evidence-based medicine.

Identification of Radiomic Signatures in Brain MRI Sequences T1 and T2 That Differentiate Tumor Regions of Midline Gliomas with H3.3K27M Mutation.

BACKGROUND: Radiomics refers to the acquisition of traces of quantitative features that are usually non-perceptible to human vision and are obtained from different imaging techniques and subsequently transformed into high-dimensional data. Diffuse midline gliomas (DMG) represent approximately 20% of pediatric CNS tumors, with a median survival of less than one year after diagnosis. We aimed to identify which radiomics can discriminate DMG tumor regions (viable tumor and peritumoral edema) from equivalent midline normal tissue (EMNT) in patients with the positive H3.F3K27M mutation, which is associated with a worse prognosis. PATIENTS AND METHODS: This was a retrospective study. From a database of 126 DMG patients (children, adolescents, and young adults), only 12 had H3.3K27M mutation and available brain magnetic resonance DICOM file. The MRI T1 post-gadolinium and T2 sequences were uploaded to LIFEx software to post-process and extract radiomic features. Statistical analysis included normal distribution tests and the Mann-Whitney U test performed using IBM SPSS® (Version 27.0.0.1, International Business Machines Corp., Armonk, NY, USA), considering a significant statistical p-value ≤ 0.05. RESULTS: EMNT vs. Tumor: From the T1 sequence 10 radiomics were identified, and 14 radiomics from the T2 sequence, but only one radiomic identified viable tumors in both sequences (p < 0.05) (DISCRETIZED_Q1). Peritumoral edema vs. EMNT: From the T1 sequence, five radiomics were identified, and four radiomics from the T2 sequence. However, four radiomics could discriminate peritumoral edema in both sequences (p < 0.05) (CONVENTIONAL_Kurtosis, CONVENTIONAL_ExcessKurtosis, DISCRETIZED_Kurtosis, and DISCRETIZED_ExcessKurtosis). There were no radiomics useful for distinguishing tumor tissue from peritumoral edema in both sequences. CONCLUSIONS: Less than 5% of the radiomic characteristics identified tumor regions of medical-clinical interest in T1 and T2 sequences of conventional magnetic resonance imaging. The first-order and second-order radiomic features suggest support to investigators and clinicians for careful evaluation for diagnosis, patient classification, and multimodality cancer treatment planning.

Photo-Stacking Technique for Neuroanatomical High-Definition Photography and 3-Dimensional Modeling.

BACKGROUND: Three-dimensional (3D) neuroanatomical knowledge is vital in neurosurgery. Technological advances improved 3D anatomical perception, but they are usually expensive and not widely available. The aim of the present study was to provide a detailed description of the photo-stacking technique for high-resolution neuroanatomical photography and 3D modeling. METHODS: The photo-stacking technique was described in a step-by-step approach. The time for image acquisition, file conversion, processing, and final production was measured using 2 processing methods. The total number and file size of images are presented. Measures of central tendency and dispersion report the measured values. RESULTS: Ten models were used in both methods achieving 20 models with high-definition images. The mean number of acquired images was 40.6 (14-67), image acquisition time 51.50 ± 18.8 s, file conversion time 250 ± 134.6 s, processing time 50.46 ± 21.46 s and 41.97 ± 20.84 s, and 3D reconstruction time was 4.29 ± 0.74 s and 3.89 ± 0.60 s for methods B and C, respectively. The mean file size of RAW files is 1010 ± 452 megabyte (MB) and 101.06 ± 38.09 MB for Joint Photographic Experts Group files after conversion. The mean size of the final image means size is 71.9 ± 0.126 MB, and the mean file size of the 3D model means is 37.4 ± 0.516 MB for both methods. The total equipment used was less expensive than other reported systems. CONCLUSIONS: The photo-stacking technique is a simple and inexpensive method to create 3D models and high-definition images that could prove valuable in neuroanatomy training.