OBJECTIVE:To provide a comprehensive quantitative synthesis of seizure outcomes, adverse events, non-seizure outcomes, and predictors of response in pediatric patients with drug-resistant epilepsy (DRE) treated with the responsive neurostimulation (RNS) system. METHODS:A systematic search of PubMed, EMBASE, and OVID/MEDLINE (from inception through March 2026), conducted in accordance with PRISMA guidelines, identified studies reporting RNS outcomes in patients ≤18 years. Primary outcome was seizure responder rate (≥50% reduction). Secondary outcomes included seizure freedom (100% reduction), super-responder rate (≥90% reduction), adverse events, and non-seizure outcomes. Pre-specified meta-regression examined mean age, follow-up duration, proportion with generalized epilepsy, and proportion with thalamic lead placement as predictors of seizure response. Risk of bias, certainty of evidence, and publication bias were assessed. RESULTS:Thirty-nine studies (Total n = 413 patients; median n= 7; median follow-up 18.7 months) were included, predominantly retrospective, with one prospective study. The pooled seizure responder rate (≥50% reduction) was 64.8% (95% CI: 59.7%-69.5%; I² = 0%). The pooled seizure freedom rate was 2.9% (95% CI: 1.0%-8.0%) and the super-responder rate (≥90% reduction) was 28.4% (95% CI: 20.5%-37.9%). Longer follow-up duration was the only significant predictor of seizure freedom on meta-regression (β = 0.046, p = 0.009); mean age, epilepsy type, and thalamic lead placement did not significantly predict seizure freedom, and no predictors were identified for seizure responder or super-responder outcomes. The pooled adverse event rate was 15.8% (95% CI: 10.9%-22.4%); device-related infection (∼4%) was the most common. Non-seizure outcomes - including quality of life, cognition, and behavior - were generally stable or improved across 12 reporting studies. Publication bias was noted (Egger's p = 0.029). SIGNIFICANCE:In this most comprehensive review to date, RNS provides meaningful seizure reduction in ∼two-thirds of pediatric DRE patients and a manageable safety profile, supporting selective off-label use while highlighting the need for prospective, multicenter, long-term data.

Hydrocephalus is a disorder of cerebrospinal fluid circulation that leads to ventricular enlargement and increased intracranial pressure. Presentation and imaging choice vary with age: infants often develop progressive macrocephaly because of skull compliance, whereas older children more commonly present with headache, vomiting, and lethargy. In newly suspected hydrocephalus, imaging confirms ventricular dilation, helps assess acuity, may identify an underlying cause, and informs management. In patients with cerebrospinal fluid diversion, imaging primarily evaluates suspected shunt malfunction, with modality selection driven by clinical urgency, patient cooperation, and age. In infants with open fontanelles, cranial ultrasound provides rapid assessment of ventricular size. MRI is generally preferred to define ventricular caliber and sites of obstruction; abbreviated/rapid MRI can shorten examinations and may avoid sedation. Noncontrast CT is useful when rapid evaluation is required or MRI is not feasible.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Introduction Outcomes following vagus nerve stimulation (VNS) are difficult to predict prior to surgery in pediatric drug-resistant epilepsy (DRE). We investigated whether structural brain differences among children may explain variability in VNS response. Methods A pediatric-specific brain-age model was developed using structural MRI from 2,623 healthy individuals aged 1.9 to 90 years, capturing nonlinear neurodevelopmental trajectories. Model accuracy was evaluated using cross-validation and independent validation in a pediatric cohort. The model was then applied to a multicenter cohort of 126 children with DRE treated with VNS. Results The brain-age model demonstrated high accuracy (R2 = 0.93; mean absolute error = 3.5 years) and generalized well to an independent pediatric cohort (mean absolute error = 2.16 years). Applied to the VNS cohort, it revealed significantly elevated brain-age gaps (BrainAGEgap) compared to age- and sex-matched controls (t = 6.27, p < 0.0001), indicating cumulative structural divergence from age-referenced norms. BrainAGEgap correlated with baseline seizure burden and postoperative changes in seizure frequency. Lower pre-surgical BrainAGEgap predicted a significantly higher likelihood of becoming a clinical responder to VNS (p = 0.01). Local age within the cingulate cortex, thalamus, nucleus accumbens, and prefrontal cortex contributed disproportionately to BrainAGEgap differences, aligning with VNS-related circuitry. Conclusion Developmental structural differences can be summarized using a robust, single-metric biomarker that reflects both disease burden and treatment responsiveness. BrainAGEgap may support individualized prognostic assessment and improve clinical decision-making in pediatric DRE undergoing neuromodulation.

Objective Although vagus nerve stimulation (VNS) is the most common implantable therapy for drug-resistant epilepsy (DRE), there is a need to develop novel methods to predict treatment response before surgery. An integrated approach combining structural and functional neuroimaging data to infer biophysical brain features at the mesoscopic scale could provide insights into brain-network differences related to response. The Virtual Brain (TVB) offers a computational framework to simulate individual subject brain dynamics using biophysical neural mass models to estimate synaptic transmission properties in the brain. This study aims to (i) assess the ability of TVB-based modeling to capture individual brain dynamics in pediatric DRE, (ii) evaluate the relationship between predictability of brain dynamics using a biophysical approach and VNS outcome, and (iii) identify regional inhibitory features as potential biomarkers of VNS response. Materials and Methods Preimplantation functional and diffusion magnetic resonance imaging data were acquired and used to construct personalized virtual brains using the reduced Wong-Wang model. The model was optimized for individual participants, and both local and global parameters of the models were compared between responders and nonresponders to VNS. Results A total of 38 children with DRE undergoing VNS implantation were included in this multicenter study, including 16 responders and 22 nonresponders. Predictability of the functional connectivity using the biophysical model was significantly lower in nonresponders, implicating atypical brain dynamics in VNS outcomes. TVB simulations showed stronger inhibitory synaptic weights in critical regions of the vagal afferent network in responders compared with nonresponders, including the thalamus, cingulate, and frontal cortices. Conclusions This study constitutes the first work exploring TVB in pediatric DRE and VNS. Personalized brain dynamics simulations revealed distinct inhibitory patterns between responders and nonresponders, offering new insights into the interindividual variability in VNS outcomes and mechanisms of action of VNS therapy.

BACKGROUND:Lennox-Gastaut syndrome (LGS) is a severe, drug-resistant developmental and epileptic encephalopathy for which corpus callosotomy (CC) can be a particularly effective option for seizure control. However, this benefit must be weighed against the tradeoff of permanent corpus callosum disconnection. Although use of CC declined with the rise of neuromodulation, interest has resurged with minimally invasive techniques, including laser interstitial thermal therapy and endoscope-assisted approaches. However, updated LGS-specific outcomes following CC have not been systematically synthesized across surgical approaches and age groups. METHODS:We conducted a systematic review and meta-analysis (PROSPERO: CRD420261381787) adhering PRISMA 2020 guidelines. PubMed, EMBASE, OVID/MEDLINE, and CENTRAL were searched from inception to March 2026. The primary outcome was ≥ 50% seizure reduction. Secondary outcomes included ≥ 75% reduction, seizure freedom, complication rates, and non-seizure outcomes. Pre-specified subgroup analyses evaluated extent of disconnection and approach (open vs laser vs endoscopic). Meta-regression assessed age at surgery, age at seizure onset, follow-up duration, extent and approach of surgery. We also performed sensitivity analyses excluding high-bias or influential studies, assessed publication bias, and graded certainty of evidence. RESULTS:After screening 1235 articles, 48 (822 patients; 46 retrospective, 2 prospective; no randomized trials) studies from 19 countries were included. The pooled ≥ 50% responder rate was 69.6% (95% CI: 63.1-75.5%; I² = 24.1%; k = 48). The ≥ 75% responder rate was 38.2% (95% CI: 29.8-47.4%; I² = 62.9%; k = 47), and seizure freedom was 20.4% (95% CI: 16.0-25.7%; I² = 0.6%; k = 20). No significant differences were observed by extent or approach. In meta-regression, older age at surgery was the only significant independent predictor of ≥ 50% response in the multivariable model (β = 0.045; p = 0.020). Non-seizure outcomes were limited and qualitatively synthesized. The pooled proportion of complications was 15.8% (95% CI, 10.4% - 23.2%). No publication bias was detected, though all outcomes carried very low certainty ratings. SIGNIFICANCE:CC achieves ≥ 50% seizure reduction in ~70% of LGS patients. Outcomes were not influenced by surgical extent or approach. Evidence is limited to observational studies with very low certainty, highlighting the need for prospective, standardized, multicenter data.

BACKGROUND:Intracranial germinomas are rare pediatric tumors classically occurring in the pineal region, the infundibular recess, and septal region. Hypothalamic-optic pathway gliomas are typically pilocytic astrocytomas that can occur at any point along the optic pathway or within the hypothalamus. Germinomas are highly radiosensitive and chemotherapy-sensitive with an overall good prognosis after treatment. In contrast, hypothalamic-optic pathway gliomas are typically managed with observation if asymptomatic and treated with chemotherapy or targeted therapies if they are symptomatic or progressive. OBSERVATIONS:Suprasellar germinomas are a known alternative location; however, suprasellar germinomas extending along the optic pathway are exceedingly rare. Neurosurgeons, neuroradiologists, and neuro-oncologists should consider germinomas when crafting a differential around a midline suprasellar lesion involving the optic pathway. Given the differences in treatment of a germinoma versus an optic pathway glioma, obtaining sufficient tissue for a diagnosis is paramount in these rare cases with radiographic equipoise. LESSONS:The authors report a case of a suprasellar germinoma mimicking an optic pathway glioma in its radiographic appearance. The intraoperative appearance of the lesion during the attempted transsphenoidal biopsy appeared consistent with an optic pathway glioma. Subsequent biopsy via a pterional approach confirmed the diagnosis of germinoma. https://thejns.org/doi/10.3171/CASE24804.

BACKGROUND:Quality improvement efforts across pediatric trauma centers have expanded recently in large part because of the American College of Surgeons Pediatric Trauma Quality Improvement Program. However, consensus on quality indicators (QI) specific to pediatric trauma that measure "quality of care" in this population is lacking. This study aims to identify pediatric-specific trauma QI. STUDY DESIGN:An expert panel of pediatric trauma leaders was convened. The panel met virtually to define and refine potential QI using a modified Delphi method, prioritizing indicators to include representing important QI for pediatric trauma. A comprehensive list of defined QI was created to improve the quality of pediatric trauma care. RESULTS:14 experts were included in the panel. After 3 rounds of anonymous voting and meetings, 52 QI were chosen, including 25 outcome, 21 process, and 6 structure variables and spanning 6 domains of quality as defined by the Agency for Healthcare Research and Quality. Indicators comprised 22 unchanged from pTQIP, 10 adapted from currently reported in pTQIP, and 20 new. Indicators encompassed unique treatment pathways for pediatric patients, timeliness of care, screening and prevention of future injuries, and long-term outcomes. CONCLUSION:A modified Delphi method was used to develop a novel list of pediatric trauma QI to inform quality improvement and benchmarking efforts for pediatric trauma care. Analysis of outcomes is required to understand the accuracy and usefulness of these newly proposed and existing indicators. This study serves as a starting point for the incorporation of new QI within national quality improvement initiatives. STUDY TYPE AND LEVEL OF EVIDENCE:Survey type study, level 4 evidence.

OBJECTIVES:Responsiveness to vagus nerve stimulation (VNS) in children with drug-resistant epilepsy (DRE) is often defined based on reduction in seizure frequency, typically at the 50% threshold, with limited consideration to the effects of therapy on seizure severity and health-related quality of life (HRQoL). In the current report, we sought to better characterize the effects of VNS beyond seizure frequency in children with DRE. METHODS:Sixty-seven children from the Connectomic profiling and Vagus nerve stimulation Outcomes Study (CONNECTiVOS) database, a multicenter study including children aged 0-18 who underwent VNS at eight North American centers, were included. Data were collected prospectively at baseline and 6, 12, and 24 months after VNS. Seizure outcomes were assessed using the 50% threshold, percentage change in seizure count and change on a frequency timescale, a categorical measure of seizure occurrence (e.g., daily to weekly seizures). The Seizure Severity Questionnaire and the Quality of Life in Childhood Epilepsy were also collected. Linear mixed models were constructed to study longitudinal changes in seizure severity and HRQoL. RESULTS:Among 67 children, 55.2% experienced >50% reduction in seizures, whereas only 37.3% demonstrated reductions in seizure timescales. Notably, 17.9% experienced no reduction in timescales despite meeting the 50% threshold. Furthermore, 31.9% of children experienced a meaningful improvement in seizure severity without any reduction in seizure timescales. HRQoL improvements were driven by the reduction in timescales (mean yearly increase of 3.65; 95% confidence interval [CI]: 0.71-6.52, p = 0.023), rather than responsiveness based on the 50% threshold or percentage change in seizure counts (p > 0.05). Reduced overall seizure severity was also independently associated with higher HRQoL after VNS (p = 0.035). SIGNIFICANCE:The conventional 50% responder threshold failed to capture meaningful gains in HRQoL, which aligned more closely with seizure timescales. Furthermore, nearly one-third of children realized improvements in seizure severity without any reduction in timescales. Improvements in both seizure frequency timescales and seizure severity drive postoperative HRQoL gains.

BACKGROUND AND OBJECTIVES:Despite strong evidence supporting timely surgical evaluation, many children with drug-resistant epilepsy undergo multiple antiseizure medication (ASM) trials before surgery. Because guidelines recommend evaluation after failure of 2 appropriate ASMs, evaluation after failure of >2 ASMs serves as a clinically relevant benchmark. The aim of this study was to identify factors associated with initiation of surgical evaluation after failure of >2 ASMs and evaluate its association with seizure freedom. METHODS:We performed a retrospective analysis using the Pediatric Epilepsy Research Consortium Surgery Database, including 24 US pediatric epilepsy centers. Children aged 18 years and younger who initiated epilepsy surgery evaluation between January 2018 and February 2023 were included. Timing of evaluation was defined by the number of ASM failures before first phase I evaluation (≤2 vs >2). Unadjusted analyses and multivariable logistic regression were used to identify predictors of later evaluation and assess its association with seizure freedom, adjusting for etiology, seizure type, MRI findings, and surgical procedure. RESULTS:Among 1,767 patients, 802 (45.4%) initiated surgical evaluation after failing ≤2 ASMs and 965 (54.6%) after failing >2 ASMs, with a median age at seizure onset of 5.96 and 4.00 years, respectively. Factors independently associated with later initiation of surgical evaluation included genetic etiology (odds ratio [OR] 1.83, 95% CI 1.28-2.60), generalized seizures (OR 2.64, 95% CI 1.58-4.40), daily seizures (OR 1.69, 95% CI 1.33-2.14), multiple seizure types (OR 1.59, 95% CI 1.39-1.82), normal MRI (OR 1.82, 95% CI 1.52-2.18), and abnormal neurologic examination (OR 2.44, 95% CI 2.01-2.96). Surgical intervention rates were similar (∼50%) between groups. Patients who initiated surgical evaluation after failure of ≤2 ASMs had significantly higher seizure freedom rates (60.8% vs 39.3%, p < 0.001). On multivariable analysis, failure of >2 ASMs before surgical evaluation was independently associated with lower odds of seizure freedom (OR 0.66, 95% CI 0.45-0.96, p = 0.028). DISCUSSION:Initiation of surgical evaluation after failure of more than 2 ASMs is associated with more complex epilepsy phenotypes and lower rates of seizure freedom. However, 80% of these patients still experienced a >50% reduction in seizures, highlighting the therapeutic benefits of timely epilepsy surgery-even when seizure freedom is unlikely-regardless of epilepsy subtype.

Thalamic neuromodulation has emerged as a treatment option for drug-resistant epilepsy (DRE) with widespread and/or undefined epileptogenic networks. While deep brain stimulation (DBS) and responsive neurostimulation (RNS) depth electrodes offer means for electrical stimulation of the thalamus in adult patients with DRE, the application of thalamic neuromodulation in pediatric epilepsy remains limited. To address this gap, the Neuromodulation Expert Collaborative was established within the Pediatric Epilepsy Research Consortium (PERC) Epilepsy Surgery Special Interest Group. In this expert review, existing evidence and recommendations for thalamic neuromodulation modalities using DBS and RNS are summarized, with a focus on the anterior (ANT), centromedian(CMN), and pulvinar nuclei of the thalamus. To-date, only DBS of the ANT is FDA approved for treatment of DRE in adult patients based on the results of the pivotal SANTE (Stimulation of the Anterior Nucleus of Thalamus for Epilepsy) study. Evidence for other thalamic neurmodulation indications and targets is less abundant. Despite the lack of evidence, positive responses to thalamic stimulation in adults with DRE have led to its off-label use in pediatric patients. Although caution is warranted due to differences between pediatric and adult epilepsy, the efficacy and safety of pediatric neuromodulation appear comparable to that in adults. Indeed, CMN stimulation is increasingly accepted for generalized and diffuse onset epilepsies, with recent completion of one randomized trial. There is also growing interest in using pulvinar stimulation for temporal plus and posterior quadrant epilepsies with one ongoing clinical trial in Europe. The future of thalamic neuromodulation holds promise for revolutionizing the treatment landscape of childhood epilepsy. Ongoing research, technological advancements, and collaborative efforts are poised to refine and improve thalamic neuromodulation strategies, ultimately enhancing the quality of life for children with DRE.

Purpose To provide consensus-based recommendations for use of vagus nerve stimulation (VNS) therapy in the management of pediatric epilepsy. Methods Delphi methodology with two rounds of online survey was used to build consensus. A steering committee developed 43 statements related to pediatric epilepsy and the use of VNS therapy, which were evaluated by a panel of 12 neurologists/neurosurgeons with expertise in pediatric epilepsy, who graded their agreement with each statement on a scale of 1 (“I do not agree at all”) to 5 (“I strongly agree”). For each statement, consensus was established if ≥70% of the agreement scores were 4 or 5 and <30% were 1 or 2 in the final survey. Results Twenty-four statements regarding the need for seizure reduction in pediatric epilepsy, the recommended treatment algorithm, the benefits and safety of VNS therapy, management of side effects of VNS therapy, patient selection for VNS therapy, and the use, dosing, and titration of VNS therapy achieved consensus. VNS and other neuromodulation therapies should be considered for pediatric patients with drug-resistant epilepsy who are not candidates for resective surgery, or who do not remain seizure free after resective surgery. When VNS therapy is initiated, the target dose range should be achieved via the fastest and safest titration schedule for each patient. Scheduled programming can be helpful in dose titration. Conclusion The expert consensus statements represent the panelists’ collective opinion on the best practice use of VNS therapy to optimize outcomes in the management of pediatric epilepsy.

PURPOSE:Central nervous system (CNS) embryonal tumors are a diverse group of malignant tumors typically affecting pediatric patients that recently have been better defined, and this paper describes evolution of a unique type of embryonal tumor at relapse.METHODS:Two pediatric patients with CNS embryonal tumors with EWSR1-PLAGL1 rearrangements treated at Arkansas Children's Hospital with histopathologic and molecular data are described.RESULTS:These two patients at diagnosis were classified as CNS embryonal tumors with EWSR1-PLAGL1 rearrangements based on histologic appearance and molecular data. At relapse both patient's disease was reclassified as atypical teratoid rhabdoid tumor (ATRT) based on loss of INI-1, presence of SMARCB1 alterations, and methylation profiling results.CONCLUSION:CNS embryonal tumors with EWSR1-PLAGL1 rearrangements acquire or include a population of cells with SMARCB1 alterations that are the component that predominate at relapse, suggesting treatment aimed at this disease component at diagnosis should be considered.

OBJECTIVE:Congenital anomalies of the atlanto-occipital articulation may be present in patients with Chiari malformation type I (CM-I). However, it is unclear how these anomalies affect the biomechanical stability of the craniovertebral junction (CVJ) and whether they are associated with an increased incidence of occipitocervical fusion (OCF) following posterior fossa decompression (PFD). The objective of this study was to determine the prevalence of condylar hypoplasia and atlas anomalies in children with CM-I and syringomyelia. The authors also investigated the predictive contribution of these anomalies to the occurrence of OCF following PFD (PFD+OCF). METHODS:The authors analyzed the prevalence of condylar hypoplasia and atlas arch anomalies for patients in the Park-Reeves Syringomyelia Research Consortium database who underwent PFD+OCF. Condylar hypoplasia was defined by an atlanto-occipital joint axis angle (AOJAA) ≥ 130°. Atlas assimilation and arch anomalies were identified on presurgical radiographic imaging. This PFD+OCF cohort was compared with a control cohort of patients who underwent PFD alone. The control group was matched to the PFD+OCF cohort according to age, sex, and duration of symptoms at a 2:1 ratio. RESULTS:Clinical features and radiographic atlanto-occipital joint parameters were compared between 19 patients in the PFD+OCF cohort and 38 patients in the PFD-only cohort. Demographic data were not significantly different between cohorts (p > 0.05). The mean AOJAA was significantly higher in the PFD+OCF group than in the PFD group (144° ± 12° vs 127° ± 6°, p < 0.0001). In the PFD+OCF group, atlas assimilation and atlas arch anomalies were identified in 10 (53%) and 5 (26%) patients, respectively. These anomalies were absent (n = 0) in the PFD group (p < 0.001). Multivariate regression analysis identified the following 3 CVJ radiographic variables that were predictive of OCF occurrence after PFD: AOJAA ≥ 130° (p = 0.01), clivoaxial angle < 125° (p = 0.02), and occipital condyle-C2 sagittal vertical alignment (C-C2SVA) ≥ 5 mm (p = 0.01). A predictive model based on these 3 factors accurately predicted OCF following PFD (C-statistic 0.95). CONCLUSIONS:The authors' results indicate that the occipital condyle-atlas joint complex might affect the biomechanical integrity of the CVJ in children with CM-I and syringomyelia. They describe the role of the AOJAA metric as an independent predictive factor for occurrence of OCF following PFD. Preoperative identification of these skeletal abnormalities may be used to guide surgical planning and treatment of patients with complex CM-I and coexistent osseous pathology.

Developmental and epileptic encephalopathies (DEEs) are a group of childhood-onset epilepsy syndromes characterized by frequent seizures, severe cognitive and behavioral impairments, and poor long-term outcomes. These conditions are typically refractory to currently available medical therapies, prompting recent exploration of neuromodulation treatments such as deep brain stimulation (DBS) and responsive neurostimulation (RNS), which aim to modulate epileptic networks spanning cortical and subcortical regions. These advances have occurred alongside an improved understanding of syndrome-specific and interictal epileptiform discharge/seizure-specific brain networks. By targeting key nodes within these networks, DBS and RNS hold promise for influencing seizures and associated cognitive and behavioral comorbidities. Initial experiences with centromedian (CM) thalamic DBS for Lennox-Gastaut syndrome (LGS) have shown modest efficacy across multiple seizure types. Reports also indicate the application of DBS and RNS across various genetic and structural etiologies commonly associated with DEEs, with mixed success. Although DBS and RNS are increasingly used in LGS and other DEEs, their mixed efficacy highlights a knowledge gap in understanding why some patients with LGS do not respond and which neuromodulation approach is most effective for other DEEs. To address these issues, this review first discusses recent neuroimaging studies showing similarities and differences in the epileptic brain networks underlying various DEEs, revealing the common involvement of the thalamus and the default-mode network (DMN) across multiple DEEs. We then examine thalamic DBS for LGS to illustrate how such network insights may be used to optimize neuromodulation. Although network-based neuromodulation is still in its infancy, the LGS model may serve as a framework for other DEEs, where optimal treatment necessitates consideration of the underlying epileptic networks. Lastly, the review suggests future research directions, including individualized connectivity assessment and biomarker identification through collaborative efforts, which may enhance the therapeutic potential of neuromodulation for individuals living with DEEs.

Arachnoid cysts are the most common incidentally discovered intracranial lesions on imaging and the most common cystic intracranial lesions. They may be developmental or secondary. A relative lack of recent literature and any comprehensive radiological review on arachnoid cysts has led to a general lack of awareness among radiologists of symptomatic or complicated arachnoid cysts. This is particularly concerning in pediatric patients. While arachnoid cysts are asymptomatic in most cases, they can cause clinical symptoms in a minority of cases, especially when they occur in unusual sites. These include intraventricular locations where they may cause hydrocephalus, the basal cisterns where they may compress cranial nerves, the cerebellopontine angle where they have to be differentiated from a number of cystic lesions, the cavum septum pellucidum or cavum velum interpositum, the choroid fissure where they can entrap the temporal horn and compress the hippocampus, the posterior fossa where they need to be differentiated from other posterior fossa cystic lesions, and within the spinal canal where there is a concern for cord or nerve root compression. Larger cysts are more prone to complications such as mass effect, hemorrhage, and rupture. Hemorrhage and rupture often present with acute symptoms. Ruptured cysts lose their characteristic imaging appearance and can mimic several ominous pathologies. It therefore becomes vital to accurately diagnose these cases as complications of pre-existing arachnoid cysts for appropriate management. A detailed review of all diagnostic imaging aspects of arachnoid cysts will help fill in the existing information void on this important entity.

Background Traumatic cervical spine injury (CSI) is fundamentally different in children, and imaging recommendations vary; however, prompt diagnosis is necessary. Methods We conducted a retrospective cohort study, evaluating children who presented after traumatic injury from 7/1/2012 to 12/31/2019 receiving a cervical spine CT. Evaluation of the incidence and clinical significance of CSI undetected on CT subsequently diagnosed on MRI was conducted. Additionally, all with CSI underwent image review to evaluate for potential overlooked, but visible pathology. Results 1487 children underwent a cervical spine CT, revealing 52 with CSI. 237 underwent MRI due to an abnormal CT or continued clinical concern. Ultimately, three were discovered to have clinically significant CSI missed on CT. In all cases, retrospective review demonstrated a retroclival hematoma when soft tissue windows were formatted in sagittal and coronal views. Conclusions A normal CT may be sufficient to rule-out clinically significant CSI. However, the presence of a retroclival hematoma must be evaluated.