Cerebral Hemispheres Research Articles

TREATMENT OPTIONS FOR RECURRENT MALIGNANT DIFFUSE ASTROCYTOMA (WHO GRADE IV)

Objectives We present the case of a 37-year-old female who underwent partial resection in 2018 for a diffuse fibrillary astrocytoma (WHO II) that invaded almost the entire right cerebral hemisphere. The patient followed conventional radiotherapy and chemotherapy. She presents after 6 years of regularly follow-ups with left hemiparesis, intracranial hypertension syndrome and tumor recurrence on MRI. The patient underwent another surgical intervention and the new histopathological diagnosis was diffuse astrocytoma grade IV. Therapeutic options for these patients are limited considering the fact that a gross total resection or a conventional re-irradiation could impact the quality of life. Therefore, exploring new therapeutic methods, such as targeted molecular therapy like EGFR antagonists or proteasome inhibitors, or proton therapy, should be considered. Material and Methods We conducted extensive research in two public medical databases for information related to the molecular pathways and management of primary and recurrent malignant astrocytoma and relevant articles were selected. Subsequently, we correlated this information with our direct experience in our case and discussed the observed results. Results Treatment modalities for these patients include reintervention, re-irradiation and second line chemotherapeutics. In relapsing cases the goal of reintervention is both to alleviate symptoms and obtain tumoral tissue for immunohistochemical analysis for identification of the new mutations. Conventional re-irradiation for large lesions carries high risks of producing both short-term and long-term side effects, impacting the quality of life. Alternatively, proton therapy minimizes the risk of adverse events due to Bragg peak reducing the irradiation of the surrounding tissue. Conclusions Genetic characterization of these lesions can facilitate targeted molecular therapy and help in establishing the prognosis. Re-irradiation of malignant astrocytomas with proton therapy is an effective treatment measure allowing for comparable tumor control to conventional radiotherapy.

Association of the Volumes of Limbic Brain Structures with the Development of Psychoneurological Disorders in Patients with Ischemic Stroke

Post-stroke depressive disorders (PSD) and post-stroke cognitive impairments (PCI) are frequent consequences of ischemic stroke (IS). The study was focused on exploring possible associations between relative volumes of cortical and limbic brain structures during the acute period of IS, and changes in biochemical indices of hypothalamic-pituitary-adrenal, sympathoadrenal medullary and inflammatory systems, with the development of PSD or PCI after mild or moderate IS. Patients developing PSD later on had significantly smaller relative volumes of the hippocampus, entorhinal cortex, and temporal pole versus patients without depressive symptoms. PCI development was associated with significantly smaller volumes of temporal pole and supramarginal gyrus versus patients without cognitive changes. Multiple logistic regression analysis showed higher likelihood of developing PSD in patients with smaller temporal pole volume (β0 =10.9; β = –4.27; p = 0.04) and in-creased salivary α-amylase activity (β0 = –3.55; β = 2.68e–05; p = 0.02). PCI likelihood was higher in patients with smaller supramarginal gyrus volume (β0 = 3.41; β = –0.99; p = 0.047), smaller temporal pole volume (β0 = 3.41; β = –3.12; p = 0.06), and increased hair cortisol concentration at admission (index of accumulated stress load within a month before IS; β0 = 3.41; β = –0.05; p = 0.08). The data support the hypothesis suggesting predisposition to PSD and PCI and multi hit scenarios of their pathogenesis with IS providing a final hit.

Cortical structural network characteristics in non-cognitive impairment end-stage renal disease

ObjectiveExplore alterations in topological features of gray matter volume (GMV) and structural networks in non-cognitive impairment end-stage renal disease (Non-CI ESRD).Materials and methodsUtilizing graph theory, we collected structural magnetic resonance imaging (sMRI) data from 38 Non-CI ESRD patients and 50 normal controls (NC). We compared, and extracted the GMV across subject groups, constructed corresponding structural covariance networks (SCNs), and investigated the alterations in SCNs feature parameters between groups.ResultsIn Non-CI ESRD patients, The GMV were reduced in several brain regions, predominantly on the left side (p < 0.05, FWE correction). The small-world network characteristics of the patient group’s brain networks showed a tendency toward regular. In a few densities, global network parameters, transitivity, (p < 0.05) was significantly increased in the ESRD group. Regional network measurements revealed inconsistent changes in regional efficiency across different brain areas. In the analysis of network hubs, the right temporal pole is likely a compensatory hub for Non-CI ESRD patients. The SCNs in Non-CI ESRD patients demonstrated reduced topological stability against targeted attacks.ConclusionThis study reveals that patients with renal failure exhibited subtle changes in brain network characteristics even before a decline in cognitive scores. These changes involve compensatory activation in certain brain regions, which enhances network transitivity to maintain the efficiency of whole-brain network information integration without significant loss. Additionally, the SCNs characteristics can serve as a neuroanatomical marker for brain alterations in Non-CI ESRD patients, offering new insights into the mechanisms of early brain injury in ESRD patients.

Rasmussen Encephalitis: Clinical Features, Pathophysiology, and Management Strategies—A Comprehensive Literature Review

Rasmussen encephalitis (RE) is a rare and progressive form of chronic encephalitis that typically affects one hemisphere of the brain and primarily occurs in pediatric individuals. The current study aims to narratively review the literature about RE, including historical information, pathophysiology, and management of this condition. RE often occurs in individuals with normal development, and it is estimated that only a few new cases are identified each year in epilepsy centers. Approximately 10% of cases also occur in adolescents and adults. The hallmark feature of RE is drug-resistant focal seizures that can manifest as epilepsia partialis continua. Also, patients with RE usually develop motor and cognitive impairment throughout the years. Neuroimaging studies show progressive damage to the affected hemisphere, while histopathological examination reveals T-cell-dominated encephalitis with activated microglial cells and reactive astrogliosis. The current therapy guidelines suggest cerebral hemispherotomy is the most recommended treatment for seizures in RE, although significant neurological dysfunction can occur. Another option is pharmacological management with antiseizure medications and immunomodulatory agents. No significant progress has been made in understanding the pathophysiology of this condition in the last decades, especially regarding genetics. Notably, RE diagnosis still depends on the criteria established by Bien et al., and the accuracy can be limited and include genetically different individuals, leading to unexpected responses to management.

Asymmetry of Directed Brain Connectivity at Birth in Low-Risk Full-Term Newborns

Purpose: Functional connectivity hubs were previously identified at the source level in low-risk full-term newborns by high-density electroencephalography (HD-EEG). However, the directionality of information flow among hubs remains unclear. The aim of this study was to study the directionality of information flow among source level hubs in low-risk full-term newborns using HD-EEG. Methods: A retrospective analysis of HD-EEG collected from a prospective study. Subjects included 112 low-risk full-term (37–41 weeks' gestation) newborns born in a large delivery center and studied within 72 hours of life by HD-EEG. The directionality of information flow between hubs at the source level was quantified using the partial directed coherence in the delta frequency band. Descriptive statistics were used to identify the maximum and minimum information flow. Differences in information flow between cerebral hemispheres were assessed using Student t-test. Results: There was higher information flow from the left hemisphere to the right hemisphere hubs (p < 0.05, t-statistic = 2). The brainstem had the highest information inflow and lowest outflow among all the hubs. The left putamen received the lowest information, and the right pallidum had the highest information outflow to other hubs. Conclusions: In low-risk full-term newborns, there is a significant information flow asymmetry already present, with left hemisphere dominance at birth. The relationship between these findings and the more prevalent left hemisphere dominance observed in full-term newborns, particularly in relation to language, warrants further study.

Peripheral molecular and brain structural profile implicated stress activation and hyperoxidation in methamphetamine use disorder

AimMethamphetamine use disorders (MUDs) cause widespread disruptions in metabolomic and immunologic processes, highlighting the need for new therapeutic approaches. The purpose of this study was to find molecular and neuroimaging biomarkers for methamphetamine addiction.MethodsIn this study, we recruited 231 patients with MUD at varying stages of withdrawal and 40 healthy controls to quantify the blood levels of 52 molecules using enzyme‐linked immunosorbent assay.ResultsThe overall molecular disruption caused by methamphetamine was inversely related to withdrawal time (P = 0.0008), with partial recovery observed after 1 year of follow‐up (P = 2.20 × 10−5). Molecules related to stress, immune activation, oxidative products, and cardiac injury were significantly elevated in all MUD groups, while antioxidation enzymes were downregulated. Additionally, the blood level of brain‐derived neurotrophic factor was significantly correlated with gray matter volumes in nine brain regions (fusiform gyrus, orbitofrontal cortex, temporal pole, caudate, cerebellum crus, and vermis, adjusted P < 0.05) among patients with MUD.ConclusionThese findings suggest that patients with MUD exhibit elevated levels of immune response, stress, and oxidative stress, which are associated with brain structural abnormalities.

TMET-36. INCREASED METHIONINE CYCLE DRIVES PYRIMIDINE METABOLISM IN LETHAL PEDIATRIC EPENDYMOMAS

Abstract Supratentorial ependymomas (ST-EPN) are pediatric brain tumors found in the cerebral hemisphere, driven by the oncogenic fusion of ZFTA with RELA. Other than surgery and radiotherapy, these tumors do not have effective therapeutic options. Recurrent ST-EPN tumors are highly aggressive and hard to treat, which makes these tumors lethal. To understand the disease mechanism and potentially identify or develop therapeutic targets, we established patient-derived models and interrogated the genetic and metabolic dependencies using cutting-edge, near-genome-wide genetic screening and metabolomic tools. Our integrative transcriptomics and metabolic analysis identify that the ZFTA-RELA fusion drives methionine metabolic reprogramming in the cancer stem cells to regulate permissive epigenetic status and pyrimidine nucleotide synthesis to fuel tumor growth. Limiting methionine or inhibiting MAT2A, a rate-limiting enzyme of methionine metabolism in ST-EPN cells, results in profound cell cycle arrest and make the cells vulnerable to pyrimidine inhibitors compared to other pediatric brain tumors. Thus, for treatment, along with radiotherapy, blocking the methionine cycle by using the methionine limited diet or in combination with pyrimidine metabolism inhibitors can be a novel therapeutic strategy against the aggressive paediatric ST-EPN tumors.

THE EFFECT OF NF-ΚB ON THE INTENSITY OF OXIDATIVE STRESS IN THE CEREBRAL CORTEX OF RATS UNDER THE COMBINED INFLUENCE OF THE LIGHT-DARK CYCLE, SYSTEMIC INFLAMMATORY RESPONSE, AND SODIUM GLUTAMATE ADMINISTRATION

To date, scientists have confirmed the link between the development of oxidative stress and disruptions in the light regime, as well as the systemic inflammatory response. The impact of monosodium glutamate on increasing oxidative damage to rat brain tissue has also been identified. The aim of this study was to investigate the role of the transcription factor NF-κB by examining the effect of its inhibitor, ammonium pyrrolidinedithiocarbamate, on the development of oxidative stress in the cerebral hemispheres of rats, in combination with acute desynchronosis, systemic inflammatory response, and monosodium glutamate administration. The study was conducted on 45 white Wistar rats weighing 150-200 g, divided into three groups: control (n=15), a group subjected to a combination of acute desynchronosis, systemic inflammatory response, and sodium glutamate administration (n=15), and a group exposed to the combination of acute desynchronosis, systemic inflammatory response, and received sodium glutamate and pyrrolidinedithiocarbamate (n=15). To induce acute desynchronosis, the rats were initially kept under a regular light-dark cycle (12 hours of light, 12 hours of darkness) for 3 weeks, followed by a shift in the light-dark phases by 6 hours back over the next 3 days. The systemic inflammatory response was modeled through intraperitoneal administration of Salmonella typhi lipopolysaccharide. During the first week, lipopolysaccharide was administered three times at a dose of 0.4 μg per 1 kg of body weight, and during the following seven weeks, it was given once a week. Sodium glutamate, at a dose of 30 mg/kg, dissolved in 0.5 ml of distilled water, was administered intragastrically for 20 days. The NF-kB activation inhibitor ammonium pyrrolidinedithiocarbamate (Sigma-Aldrich, Inc., USA) was administered at a dose of 76 mg/kg three times a week for 20 days. In a 10% homogenate of the cerebral hemispheres, the following were measured: the rate of superoxide anion radical production, the content of thiobarbituric acid-reactive substances (TBARS), the increase in these parameters, as well as the activity of catalase and superoxide dismutase. Administration of pyrrolidinedithiocarbamate in combination with acute desynchronosis, systemic inflammatory response, and sodium glutamate reduced the rate of basic superoxide anion radical production by 10%, NADPH-induced production by 17.6%, NADH-induced production by 13%, reduced the concentration and growth of TBC-active products by 6.6% and 14.6%, respectively, increased the activity of superoxide dismutase by 35.2%, catalase by 10.5% compared to the group exposed to the combination of acute desynchronosis, systemic inflammatory response, and sodium glutamate administration. Conclusion. The administration of pyrrolidinedithiocarbamate in combination with a systemic inflammatory response, acute desynchronosis and the action of sodium glutamate reduces the production of the superoxide anion radical, the concentration and increase in TBC-active products, enhances antioxidant protection that indicates the possible influence of the nuclear factor NF-κB on the development of oxidative processes in the cerebral hemispheres of rats.

TMOD-27. RECURRENT GLIOBLASTOMA AFTER LASER ABLATION OF THE PRIMARY TUMOR IN A PRECLINICAL ORTHOTOPIC MODEL EXHIBIT INCREASED GENETIC SIGNATURES OF CELL CYCLE AND CELL MOTILITY

Abstract Image-guided laser interstitial thermal therapy (LITT) is a minimally invasive tumor cytoreductive treatment for recurrent gliomas and tumors in eloquent loci. We have adapted this technique to develop an image-guided glioblastoma (GBM) ablation model, its recurrence and have tested the efficacy of imaging biomarkers in evaluating tumor ablation and recurrence. The cytopathology and molecular signatures of the primary and recurrent tumors were compared. Immune-compromised female rats were implanted with U251N tumor cells in one brain hemisphere (n=20). Tumor growth was monitored using magnetic resonance imaging (MRI). When tumors reached about 4 mm in diameter, they were ablated using a clinical LITT system (Visualase®), under MRI guidance. Five other rats implanted with U251N tumors were used as unablated controls. MRI data were acquired at 24 h post-LITT, and at 2 and 4 weeks. Rats were sacrificed for histopathology at 2 and 4 weeks, and brain sections stained for hematoxylin and eosin, human major histocompatibility complex, Ki67, a cell proliferation marker and sex determining region Y)-box 2 (SOX2), a stem cell transcription factor. An additional cohort of rats with primary (n=4) and post-LITT recurrent (n=4) U251N tumors were used for analysis of their molecular composition using RNA-Seq approach. In the treated groups, MRI showed little tumor tissue at 24 h, evidence of recurrence at 2 weeks and significant tumor tissue at 4 weeks. Tumor DCE-MRI parameters showed elevated intra-tumoral vascular permeability (i.e., Ktrans) values at pre-LITT imaging, that shifted to peri-ablation periphery at 24 h. A trend of progressive decrease in Ktrans was seen until 1-week post-ablation. Increasing Ktrans values at 2 weeks and after 4 weeks coincided with tumor recurrence. RNA-Seq data showed that cell cycle, cellular movement and inflammatory disease genes were the most differentially expressed genes in the recurrent tumors suggesting increased infiltration may primarily underlie treatment resistance.

NCOG-08. A RARE PRIMARY CNS T-CELL LYMPHOMA CASE: 12-YEAR FOLLOW-UP AFTER CHEMOTHERAPY

Abstract INTRODUCTION Primary central nervous system (CNS) T-cell lymphoma (PCNSTL) is a rare hematological malignancy. There is mere literature to guide the treatment. CASE REPORT This study is an update on our previously reported case at SNO in 2012 after a 12-year follow-up, detailing the long-term outcome of our chemotherapy treatment for a case of PCNSTL. In 2011, a 26-year-old immunocompetent patient presented with severe headache, vomiting, and lethargy. The brain MRI found more than a dozen masses on his bilateral cerebral hemispheres. Brain biopsy discovered T-cell lymphoma. The patient was started biweekly high-dose-methotrexate (HD-MTX) in 2011. After three doses, there was no noticeable improvement on his brain MRI. His treatment was switched to HD-MTX plus high dose cytarabine regimen (Ferreri et al, The Lancet, 2009). The patient could not tolerate cytarabine; thus, was changed back to HD-MTX. The patient responded to the rest of HD-MTX well. He completed 8 doses of biweekly HD-MTX induction therapy and 2 doses of monthly HD-MTX maintenance therapy. His brain MRI showed complete resolution of enhancement on one-year follow-up image. The patient has been off-treatment and monitored under surveillance of brain MRIs since 2012. He has had no lymphoma recurrence over the past 12 years. His physical functions have been preserved with a Karnofsky Performance Status scale of 80%. Neuropsychological evaluations in 2015, 2018, and 2023 showed mild cognitive impairment with gradual improvements in his working memory and semantic fluency. His Mini-Mental Status Exam scores have remained stable to mild improvement, recording 27/30 in 2015, 26/30 in 2018, 27/30 in 2023 and 28/30 in 2024. DISCUSSION The patient, who is now 38 years old, has surpassed a 12-year survival mark. Our experience emphasizes the feasibility of treating PCNSTL through chemotherapy only, which might be potentially beneficial in surviving and preserving major aspects of brain function.

Changes in brain functional connectivity between on and off states and their relationship with cognitive impairment in Parkinson’s disease

Parkinson’s disease (PD) is characterized by motor and non-motor symptoms. Cognitive decline is crucial in disease progression and affect quality of life; however, their underlying mechanisms in PD remain unclear. We explored the relationship between cognitive impairment and functional connectivity (FC) using resting-state functional magnetic resonance imaging in 26 patients with sporadic PD, focusing on the changes in FC between on and off states. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) score. The correlation between MMSE scores and changes in FC values during on and off states was assessed using Pearson’s correlation coefficient. The correlation between changes in FC during the on and off periods and cognitive function differed for each cognitive function item. MMSE memory scores were positively correlated with FC between the brainstem and the left cerebral hemisphere. MMSE attention scores were positively correlated with FC between the bilateral thalamus and frontal lobes and negatively correlated with FC between the left cerebral hemispheres. These findings may facilitate our understanding of the neural correlates underlying cognitive impairment in PD and help develop treatment strategies to preserve cognitive function.

Changes in the functional connections of the brain in patients with hypersomnia in acute ischemic stroke

BACKGROUND: The Disorders of cerebral circulation and sleep are inextricably related, since sleep disorders, including hypersomnia, are closely intertwined with cardiovascular diseases and increase the risk of stroke. Research works on visualization of functional brain changes in patients with sleep disorders and acute ischemic stroke are very few and need more study. AIM: to determine the functional connections of the brain in hypersomnia in patients with acute ischemic stroke by performing functional magnetic resonance imaging at rest. A study of 40 patients with acute ischemic stroke and sleep disorders was performed on the basis of the Federal State Budgetary Institution Almazov Research Center of the Ministry of Health of the Russian Federation. All patients underwent neurological examination, assessment of sleepiness, worry and depression, magnetic resonance imaging was performed on tomographs with a magnetic field induction force of 1.5T, using a standard protocol and special pulse sequences of T-gradient echo 3D MPRAGE and BOLD. Functional magnetic resonance imaging of the brain at rest was used to assess functional connections. Postprocessing was performed using specialized CONN-TOOLBOX software with an appropriate graphical representation of quantitative results based on the selection of areas of interest. RESULTS: Among the examined patients, 23 had hypersomnolence; of these, 8 patients were diagnosed with secondary hypersomnia associated with sleep apnea syndrome. Thus, in the examined sample, post-stroke hypersomnolence was detected in 15 patients (34%). Patients with an unspecified subtype of stroke and right-sided lesions showed a high degree of drowsiness (p 0.05). With the help of functional magnetic resonance imaging of the brain at rest, changes in functional connections between the main nodes of the default mode network with the left temporal pole, cerebellum, central cerebral cortex on the left, angular gyrus on the left, with the dorsal attention network on the right are determined (p 0.05). CONCLUSION: The use of complex magnetic resonance imaging, which includes structural and functional magnetic resonance imaging in patients with acute ischemic stroke and sleep disorders, allows us to identify structural changes and changes in functional connectivity and identify neuroimaging markers of this pathology. Hypersomnolence is typical for patients with an unspecified subtype of ischemic stroke and damage to the right hemisphere of the brain.

Exposure to Sunset Yellow FCF since post‐weaning causes hippocampal structural changes and memory impairment in the adult rat: The neuroprotective effects of Coenzyme Q10

AbstractBackgroundThis study aimed to investigate whether exposure to Sunset Yellow FCF (SY) since post‐weaning can lead to hippocampal structural changes and memory impairment in adult rat and whether the Coenzyme Q10 (CoQ10) can protect against these adverse effects.MethodsThe weanling rats were randomly divided into six groups and were treated daily by oral gavage for 6 weeks, as follows: (I) control group, administered distilled water (0.3 mL/100 g/day); (II) CoQ10 group, received 10 mg/kg/day CoQ10; (III) low SY group, received 2.5 mg/kg/day SY; (IV) high SY group, received 70 mg/kg/day SY; (V) low SY + CoQ10 group; and (VI) high SY + CoQ10 group. At the end of the sixth week, the novel object recognition (NOR) test was conducted to evaluate memory. Then, after sacrificing animals, the cerebral hemispheres were removed for stereological study and evaluation of MDA levels.ResultsThe low and high doses of SY led to significant neuronal loss and a decrease in the volume of the hippocampus (CA1 and DG subregions), as well as increased the MDA level, which was associated with short‐ and long‐term memory impairment. Although, administration of CoQ10 prevented the hippocampal neural loss and volume, and caused a reduction in MDA and improved memory in the low and high SY groups.ConclusionIt seems that CoQ10 could prevent the neuronal loss and hippocampal atrophy caused by post‐weaning exposure to SY through preventing oxidative stress, ultimately improving memory impairment in rats.

The interhemispheric amygdala-accumbens circuit encodes negative valence in mice.

The structurally symmetric mammalian brain hemispheres are interconnected by commissural axons across the midline. However, the functions of interhemispheric connectivity remain largely unknown. We found that in mice, transection of the anterior commissure (AC), which connects the rostroventral forebrain, impaired avoidant behaviors. The basolateral amygdala (BLA) in the mouse projects to the contralateral nucleus accumbens (NAc) through the AC, independent of its ipsilateral projections. Aversive stimuli activated contralateral BLA-NAc projections. Positive stimuli, however, activated ipsilateral projections. Selective activation of contralateral BLA-NAc projections activated D2-positive medium spiny neurons (D2-MSNs), reduced NAc dopamine levels, and caused aversion, whereas selective activation of ipsilateral BLA-NAc projections activated D1-MSNs, increased NAc dopamine levels, and induced reward. The contralateral BLA-AC-NAc pathway is crucial for encoding negative valence, demonstrating distinct functions of intra- and interhemispheric circuits in brain physiology.

Cortico-limbic volume abnormalities in late life depression are distinct from β amyloid and white matter pathologies.

This study was conducted to clarify patterns of cortico-limbic volume abnormalities in late life depression (LLD) relative to non-depressed (ND) adults matched for amyloid β (Aβ) deposition and to evaluate the relationship of volume abnormalities with cognitive performance. Participants included 116 LLD and 226 ND. Classification accuracy of LLD status was estimated using area under the receiver operator characteristic curve. Twenty-one percent of LLD and ND participants were Aβ positive and the groups did not differ on white matter hyperintensity volume (WMH (logscale); β = 0.12, p = 0.28). Compared to ND, the LLD group exhibited significantly lower bilateral volume in the lateral orbitofrontal cortex, hippocampus, accumbens area, superior temporal lobe, temporal pole, and amygdala after multiple comparison correction (p < 0.009 for all). Cortico-limbic volumes significantly improved classification of LLD beyond demographic characteristics, Aβ status, and WMH (AUCVol = 0.71, AUCWMH, Aβ = 0.62, AUC difference, 0.09 [0.03 to 0.15]). LLD exhibited poorer performance on measures of global cognition, set shifting, and verbal learning and memory relative to ND. Cognitive function was positively associated with cortico-limbic volumes and these relationships did not differ by group. Secondary analyses with an ND sample additionally matched for Mild Cognitive Impairment (MCI) diagnosis showed a similar but attenuated pattern of volume abnormalities. Overall, our results support LLD as being associated with cortico-limbic volume abnormalities that are distinct from Aβ and white matter pathologies and that these volume abnormalities are important factors associated with cognitive dysfunction in LLD.

The head of invasive cardiologists as a target of professional exposure to ionizing radiation

Exposure to ionizing radiation has recognized detrimental cancer and non-cancer health effects. These effects are now well-proven not only for high doses &gt; 1,000 millisieverts (mSv) associated with head radiotherapy but also for moderate (100–1,000 mSv) and even low (&lt; 100 mSv) doses, of interest for professionally exposed cardiologists. The head of interventional cardiologists is highly exposed to ionizing radiation, with possible damage to the eye and brain. Unprotected interventional cardiologists experience head radiation doses up to ten times greater than chest doses below lead aprons, with marked exposure to the left hemisphere of the brain reaching up to 2 Sv—equivalent to 10,000 chest X-rays over a professional lifetime. This narrative review aims to provide an overview of the background of radioprotection, the biological mechanisms involved, and the epidemiological evidence regarding the health effects of head exposure to ionizing radiation in invasive cardiologists. These health effects include cataracts, brain cancer, cerebrovascular diseases, neurodegeneration, and mood disorders. The evidence gathered from other exposed populations, which experienced similar eye and brain doses, has also been reviewed. This is important because the doses, risks, and effects are consistent in cases of repeated exposures, which occur more frequently for patients, and in situations involving chronic low doses, as seen with interventional cardiologists. Despite these risks, effective protective measures—such as suspended lead ceilings, curtains, and specialized eyewear—can reduce radiation exposure to near-zero levels. In some fields, like interventional cardiac electrophysiology, a groundbreaking near-zero radiation approach using non-fluoroscopic methods has been created, eliminating radiation exposure and alleviating orthopedic stress and operational discomfort. The race to zero radiation in interventional cardiology is ongoing.

T1-weighted MRI texture analysis in amyotrophic lateral sclerosis patients stratified by the D50 progression model

Abstract Amyotrophic lateral sclerosis (ALS), a progressive neurodegenerative disease, presents challenges in predicting individual disease trajectories due to its heterogeneous nature. This study explores the application of texture analysis on T1-weighted MRI in patients with ALS, stratified by the D50 disease progression model. The D50 model, which offers a more nuanced representation of disease progression than traditional linear metrics, calculates the sigmoidal curve of functional decline and provides independent quantifications of disease aggressiveness and accumulation. In this research, a representative cohort of 116 patients with ALS were studied using the D50 model and texture analysis on MRI images. Texture analysis, a technique used for quantifying voxel intensity patterns in MRI images, was employed to discern alterations in brain tissue associated with ALS. This study examined alterations of the texture feature autocorrelation across subgroups of patients based on disease accumulation, aggressiveness, and the first site of onset, as well as in direct regressions with accumulation/aggressiveness. The findings revealed distinct patterns of the texture-derived autocorrelation in gray and white matter, increase in bilateral corticospinal tract, right hippocampus, and left temporal pole as well as widespread decrease within motor and extra-motor brain regions, of patients stratified based on their disease accumulation. Autocorrelation alterations in grey and white matter, in clusters within the left cingulate gyrus white matter, brainstem, left cerebellar tonsil gray matter, and right inferior fronto-occipital fasciculus, were also negatively associated with disease accumulation in regression analyses. Otherwise, disease aggressiveness correlated with only two small clusters, within the right superior temporal gyrus and right posterior division of the cingulate gyrus white matter. The findings suggest that texture analysis could serve as a potential biomarker for disease stage in ALS, with potential for quick assessment based on using T1-weighted images.

Global changes in the pattern of connectivity in developmental prosopagnosia.

Developmental prosopagnosia is a neurodevelopmental condition characterized by difficulties in recognizing the identity of a person from their face. While current theories of the neural basis of developmental prosopagnosia focus on the face processing network, successful recognition of face identities requires broader integration of neural signals across the whole brain. Here, we asked whether disruptions in global functional and structural connectivity contribute to the face recognition difficulties observed in developmental prosopagnosia. We found that the left temporal pole was less functionally connected to the rest of the brain in developmental prosopagnosia. This was driven by weaker contralateral connections to the middle and inferior temporal gyri, as well as to the medial prefrontal cortex. The pattern of global connectivity in the left temporal pole was also disrupted in developmental prosopagnosia. Critically, these changes in global functional connectivity were only evident when participants viewed faces. Structural connectivity analysis revealed localized reductions in connectivity between the left temporal pole and a number of regions, including the fusiform gyrus, inferior temporal gyrus, and orbitofrontal cortex. Our findings underscore the importance of whole-brain integration in supporting typical face recognition and provide evidence that disruptions in connectivity involving the left temporal pole may underlie the characteristic difficulties of developmental prosopagnosia.

Middle meningeal artery embolization and tranexamic acid therapy for subdural hematoma in a patient with hereditary hemorrhagic telangiectasia: illustrative case.

Subdural hematoma is a rare manifestation of hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu disease. Here, the authors present a patient with HHT and a large chronic subdural hematoma, for whom nonsurgical management was pursued. A 49-year-old right-handed male with a history of hypertension and familial HHT presented with complaints of mild confusion and left hemiparesis over several days. Noncontrast head computed tomography images demonstrated a large chronic right hemisphere subdural hematoma compressing the right cerebral hemisphere and causing a 1.3-cm midline shift. Due to concerns about surgical complications arising from hemorrhages of cryptic telangiectasias, the patient was treated conservatively with middle meningeal artery embolization and adjuvant tranexamic acid. There was clinical and radiological resolution several months later. This case highlights the rarity of a subdural hematoma as a manifestation of HHT and the nonsurgical treatment strategy as a mechanism to avoid hemorrhagic complications of surgical evacuation. https://thejns.org/doi/10.3171/CASE24483.

Stimulus-induced rotary saturation imaging of visually evoked response: A pilot study.

Spin-lock (SL) pulses have been proposed to directly detect neuronal activity otherwise inaccessible through standard functional magnetic resonance imaging. However, the practical limits of this technique remain unexplored. Key challenges in SL-based detection include ultra-weak signal variations, sensitivity to magnetic field inhomogeneities, and potential contamination from blood oxygen level-dependent effects, all of which hinder the reliable isolation of neuronal signals. This pilot study evaluates the performance of the stimulus-induced rotary saturation (SIRS) technique to map visual stimulation response in the human cortex. A rotary echo spin-lock (RESL) preparation followed by a 2D echo planar imaging readout was used to investigate 12 healthy subjects at rest and during continuous exposure to 8Hz flickering light. The SL amplitude was fixed to the target neuroelectric oscillations at that frequency. The signal variance was used as contrast metric, and two alternative post-processing pipelines (regression-filtering-rectification and normalized subtraction) were statistically evaluated. Higher variance in the SL signal was detected in four of the 12 subjects. Although group-level analysis indicated activation in the occipital pole, analysis of variance revealed that this difference was not statistically significant, highlighting the need for comparable control measures and more robust preparations. Further optimization in sensitivity and robustness is required to noninvasively detect physiological neuroelectric activity in the human brain.