Adamantinomatous craniopharyngioma (ACP) is an uncommon and anatomically variable tumor in children. The balance between critical treatment objectives, including the pursuit of gross total surgical resection and the reduction of hypothalamic injury and tumor recurrence, remains difficult and controversial. In this retrospective observational study, we compare the management and outcome of ACP in two large paediatric neurosurgical centres to determine how variations in tumor characteristics and management influence long-term outcomes. In this retrospective observational study, consecutive children (aged ≤ 18 years) diagnosed with primary ACP between 1997 and 2023 at two tertiary paediatric neurosurgical centres (Great Ormond Street Hospital (GOSH), United Kingdom, and Universidade de São Paulo (USP), Brazil) were evaluated. Functional outcomes related to pituitary function, hypothalamic injury, cognition, and vision were analysed. Scans were independently reviewed for tumor size, characteristics, and relationship to the optic apparatus and hypothalamus. Extent of surgery was documented. 123 patients (USP = 52; GOSH = 71) were included. Mean follow-up was 10.1 ± 5.6 years at USP and 7.5 ± 4.8 years at GOSH. There were no demographic differences. Rates of growth hormone deficiency (USP = 62.5 June 29–July 2, 2024

Artificial intelligence (AI) is increasingly integrated into radiology, but pediatric imaging remains underrepresented in implementation studies. To assess the current status, barriers, and enablers of AI adoption in Pediatric Radiology from a global leadership perspective. A cross-sectional international survey of department leaders and division chiefs from pediatric radiology centers worldwide was conducted. The questionnaire included 14 items across domains of AI deployment, enablers, barriers, ethical concerns, stakeholder involvement, and future directions. Descriptive statistics were used for analysis. Eighteen institutions completed the survey (69

BACKGROUND AND PURPOSE:GM1 gangliosidosis is a rare lysosomal storage disorder caused by pathogenic variants in the GLB1 gene, leading to deficient β-galactosidase activity and accumulation of gangliosides. This multi-institutional retrospective study aims to systematically characterize neuroimaging features across all clinical subtypes of GM1 gangliosidosis. MATERIALS AND METHODS:Patients were retrospectively identified from 4 centers based on confirmed GLB1 variants or β-galactosidase deficiency. Imaging acquired post gene therapy or with poor quality was excluded. Clinical subtypes were classified by age of onset. A total of 35 brain MRIs and 3 CTs from 24 patients (aged 0-19 years) were reviewed. Imaging was assessed for white matter patterns, deep gray nuclei signal changes, atrophy, and the presence of occipitomastoid suture hypertrophy. RESULTS:The cohort included patients with infantile- (13), late-infantile- (6), juvenile- (4), and adult-onset (1). White matter abnormalities were present in all but one infantile/late-infantile patient and absent in juvenile/adult-onset subtypes. Patients with infantile-onset predominantly showed hypomyelination with the posterior limb of the internal capsule sparing. Late-infantile subtypes demonstrated a spectrum from mixed to nonhypomyelinating patterns, including periventricular and deep white matter involvement with sparing of subcortical regions. Internal hypertrophy of the occipitomastoid sutures was seen in more than one-half of the infantile and late-infantile-onset subtypes. One patient in the infantile cohort showed linear subcortical and basal ganglia calcifications. Thalamic T2 hypointensity with anterior and lateral nuclear group predilection was a consistent feature across all subtypes, progressing in early-onset groups. Juvenile and adult cases showed dorsal putaminal T2 hyperintensity and globus pallidus T2 hypointensity, with the latter corresponding to mineralization on SWI. Progressive cerebral and cerebellar atrophy was observed in all subtypes with available follow-up imaging. CONCLUSIONS:Distinct imaging patterns are evident across GM1 gangliosidosis subtypes: leukodystrophy dominates in early-onset forms, while juvenile and adult forms are characterized by globus pallidus mineralization and dorsal putaminal atrophy. Thalamic T2 hypointensity is consistent across all subtypes, with predilection for the anterior and lateral nuclear groups. Internal hypertrophy of the occipitomastoid sutures, previously undescribed in GM1 gangliosidosis, is a common feature of early-onset cases.

Abstract H3K27-mutant diffuse midline gliomas include a rare group of primary spinal tumours which constitute <1% of all pediatric central nervous system tumors. There is a paucity of data on their clinical and radiological characteristics, genomic landscape, and their respective impact on patient outcomes. Here, we present an interim analysis of an international, multi-institutional retrospective cohort study including patients aged <18 years from the International DIPG/DMG Registry, SIOPE (European Society for Paediatric Oncology) and HIT-HGG groups, assessing overall survival (OS) at 12 months, between January 2012 and December 2023. 86/103 patients met study inclusion criteria (54 female (63%), 32 male (37%) with median age at presentation 8 years. The median symptom interval at presentation was 5.5 weeks. 90% of patients presented with back pain and ataxia, with bladder/bowel incontinence in 10%. Median OS was 12 months. Univariate analyses demonstrated no significant association between age (<10-years vs. >10-years), sex, tumor location (cervical vs. thoracolumbar), extent of resection (subtotal/gross-total, HR = 1.094/1.128, respectively), chemotherapy (HR = 1.14), radiotherapy (photon and proton, HR = 0.93), and targeted therapy (HR = 1.2) with overall survival. Neuroimaging characteristics in 32 patients such as spinal canal widening (91%), posterior vertebral scalloping (77%), minor oedema (50%), moderate enhancement (38%), intratumoral hemorrhage (12%), and necrosis (22%) were not associated with overall survival. Of 41 (48%) patients who underwent molecular profiling, 24/41 (59%) had co-occurring TP53 somatic variants (HR = 0.67) or MAPK pathway alterations (12; 29%). Germline NF1 mutation was identified in one patient. DNA methylation profiles of 24 patients (28%) demonstrated high confidence scores (>0.9) in 7 (29%) and MGMT promoter methylation in 9 (38%). Primary spinal DMG appear to share the same molecular profile and clinical outcome with its intracranial counterpart. Understanding clinical, radiological, and biological features of these rare tumors may help to identify early prognostic indicators and improve patient survival and quality of life.

Pediatric complex Chiari I Malformation (CCM), defined by Chiari I with additional craniovertebral junction anomalies, has been associated with higher failure rates following foramen magnum decompression (FMD) alone, leading some to advocate occipitocervical fixation (OCF) or ventral decompression. This study evaluates a single-institution experience with isolated FMD in CCM. Patients meeting CCM criteria were identified from a prospective surgical database from March 2020 to December 2023. Patients with incomplete imaging or < 6-month follow-up were excluded. Pre- and postoperative imaging assessed tonsillar descent, brainstem crowding, CSF flow, and syringomyelia. Clinical outcome was recorded. Sixty patients met the inclusion criteria for CCM, but nineteen patients were excluded. Forty-one CCM patients underwent FMD. Headache prevalence decreased from 73.2

Background and Objectives The 2024 McDonald criteria provide new recommendations for multiple sclerosis (MS) diagnosis, but validation of the criteria is lacking. We wanted to investigate the application and performance of the 2024 McDonald criteria in patients with suspected MS seen in routine clinical practice. Methods We retrospectively identified patients referred with clinical and/or radiologic suspicion for MS between January and December 2024. All patients had a minimum diagnostic evaluation with brain and spinal cord MRI. The 2017 McDonald criteria were applied prospectively, and the 2024 McDonald criteria were applied retrospectively after the initial diagnostic workup and at last follow-up. We investigated (1) the number of patients diagnosed with MS using the 2017 McDonald criteria or the 2024 McDonald criteria, and (2) the diagnostic performance of the 2024 McDonald criteria when applied during the initial diagnostic workup, with an MS diagnosis using the 2017 McDonald criteria as the reference-standard. Results In 347 patients (mean age 39.4 years, 66% female) with suspected MS followed up for mean 15.3 (range 8-20) months, 73 (21%) had alternative disorders and were excluded. After applying the 2024 McDonald criteria in the remaining 274 patients, more patients were diagnosed with MS after the initial diagnostic workup (220 vs 172, p < 0.01), and at follow-up (237 vs 204, p < 0.01), compared with the 2017 McDonald criteria, and fewer patients were diagnosed with clinically or radiologically isolated syndrome. The median time to diagnosis was 40 vs 84 days (p < 0.01), respectively. After initial diagnostic workup, the 2024 McDonald criteria demonstrated high sensitivity (92.6%, 95% CI 88.1%-95.8%) and accuracy (83.6%, 95% CI 78.7%-87.8%), for an MS diagnosis using 2017 McDonald criteria at last follow-up, but moderate specificity (57.8%, 95% CI 45.4%-69.4%). The increased rate of MS diagnosis and the diagnostic performance of the revised criteria was similar in children (<18 years) and older adults (>50 years). Discussion Use of the 2024 McDonald allows for earlier MS diagnosis, but also more frequent diagnosis including in patients with radiologically isolated syndrome. The revised criteria have similar performance across the lifespan. Limitations include the lack of data on central vein sign and kappa free light chains, and missing optic nerve assessment in some patients.

Response Assessment in Pediatric Neuro-Oncology (RAPNO) is an international working group dedicated to developing standardized recommendations for response assessment in children with central nervous system (CNS) tumors enrolled on clinical trials. This standardization facilitates easier and more reliable comparison of responses across trials. Since the first RAPNO publication in 2013, response guidelines have been issued for medulloblastoma, low-grade glioma (LGG), high-grade glioma (HGG), diffuse intrinsic pontine glioma (DIPG), ependymoma, and craniopharyngioma. Many of these guidelines have already been incorporated into clinical trials to evaluate their effectiveness and accuracy. RAPNO has always been predicated on the idea that these consensus recommendations will require updates over time as they are applied in practice given technological advancements, evolving treatment approaches, and growing knowledge of disease pathology. A half-day RAPNO symposium sponsored by the Society of Neuro-Oncology (SNO) was held in San Diego, CA, USA, on May 15, 2025. This event coincided with the 8th Biennial Pediatric Society of Neuro-Oncology meeting. The main objectives were to identify ongoing RAPNO challenges, discuss potential updates, and plan future initiatives across three specific groups: 1) LGG/Craniopharyngioma, 2) HGG/Diffuse Midline Glioma (DMG)/Ependymoma, and 3) Medulloblastoma and other seeding tumors. This manuscript reviews the symposium proceedings and highlights key topics and challenges discussed, as well as outlining future RAPNO initiatives.

Lay Summary Paediatric Low-Grade Glioma (PLGG) is the commonest brain tumour of childhood. Most children and young adults under eighteen years old with PLGG will survive long-term, but many will face functional or quality of life consequences from the tumour and its required treatment. Accordingly, research efforts have focused on developing new treatments which are more effective and less toxic which target the underlying genetic changes within the MAPK pathway known to cause PLGG growth. Over the last few years, these new and targeted therapies are increasingly being used in PLGG but outside of more standardised and monitored clinical trials, without consistency regarding when to start the new therapies or the required supportive care that patients receive alongside these new drugs. We provide the first national real-world efficacy and toxicity data from a large PLGG cohort receiving MAPKi outside of clinical trials in the UK. We collected data from 50 patients treated with MAPK inhibitor therapy (MAPKi) between 2016 and 2024 across 7 UK Paediatric Brain Tumour centres. We collected standardised assessments of tumour response to treatment on MRI scan (Radiological response), visual responses in those with tumours involving the optic pathway, and survival outcomes (overall survival and progression of tumours; progression-free survival). We also collected and analysed data on treatment side effects, need for dose reductions or stopping of therapy earlier than 2 years. We calculated the ratio of duration of response on MAPKi compared to prior chemotherapy which is a recognised measure of MAPKi treatment benefit. At a median period of 3.5 years from starting MAPKi therapy, 96% of patients remained alive but 38% had tumour progression. Seventy-four percent of patients had a radiological benefit from MAPKi therapy observed on MRI imaging (stable disease 54%, partial response 20%). Of 35 patients with optic pathway tumours, 72% had visual benefit from MAPKi therapy (63% stable, 9% improved). Seventy-seven patients had a prolonged MAPKi: prior chemotherapy ratio of > 1.3: 1 demonstrating superior benefit from MAPKi therapy compared to prior chemotherapy. We conclude that MAPKi therapies provide safe and effective treatment for PLGG, with significantly prolonged periods without tumour progression compared to prior chemotherapy.

Quantitative susceptibility mapping (QSM) is an advanced magnetic resonance imaging (MRI) technique that quantifies tissue magnetic susceptibility, offering non-invasive insights into brain microstructure, including iron content and myelination. While extensively applied in adult neuroimaging, its use in pediatric populations is rapidly expanding. This systematic review aims to provide a comprehensive overview of QSM applications in pediatric brain imaging, highlighting methodological advancements, diagnostic potential, and current limitations. A systematic literature search was performed using PubMed and Google Scholar up to April 2025. Inclusion criteria were original research articles written in English, involving only pediatric populations (0–17 years) and employing QSM in brain imaging. Twenty studies met eligibility criteria and were analyzed in terms of acquisition protocols, post-processing methods, study objectives, and main findings. A systematic search on PubMed and Google Scholar found 54 QSM brain studies in children; after exclusions, 20 original research papers qualified for review and were quality-checked using Quality Assessment of Diagnostic Accuracy Studies version-2 (QUADAS-2). Most studies were recent (85

BACKGROUND AND OBJECTIVES:Central vein sign (CVS) is a common feature in multiple sclerosis (MS) lesions, but its frequency in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) varies significantly across studies. Paramagnetic rim lesions (PRLs) are described in MS, but not in MOGAD. Our goals were to evaluate the prevalence of PRLs and CVS in a large multicenter cohort of pediatric MOGAD. We compared CVS frequencies between acute vs remission phases, as well as with longitudinal dynamics of lesion evolution. METHODS:In this longitudinal retrospective multicenter study, clinical MRIs were assessed from pediatric patients with MOGAD, who had (1) ≥1 brain lesion, (2) susceptibility-based imaging (SBI), and (3) follow-up MRI at least 3 months apart. T2-weighted and fluid-attenuated inversion recovery sequences were analyzed for lesion detection and resolution. SBI was used to assess CVS and PRLs following North American Imaging in MS Cooperative criteria. RESULTS:A total of 65 patients and 130 scans were included. A total of 520 lesions were evaluated. The most common reason for lesion exclusion was size (n = 143, large confluent lesions, n = 122, <3 mm, n = 21). CVS was detected in 97 of 327 (29.7%) lesions, with 32 of 65 (49.2%) patients having at least 1 CVS+ lesion. Patients with ≥1 CVS+ lesion (32/65, 49.2%) had a higher number of lesions (p = 0.002) and lesions suitable for CVS analysis (p < 0.001). Of the 31 patients with ≥3 brain lesions, 11 of 31 (35.5%) had >40% CVS+ lesions and 7 (22.5%) had >50% CVS+ lesions. Only 4 patients had ≥6 CVS+ lesions. The proportion of CVS+ lesions was lower in patients who had SBI acquired during an acute attack vs patients scanned during remission (16% vs 33%, p = 0.015). The rate of lesion resolution was higher in CVS- lesions (177/230, 76%) compared with CVS+ (42/97, 42%, p < 0.001). No PRLs were identified. DISCUSSION:Lesion pathobiology in MOGAD is heterogeneous. CVS identified persistent rather than transient lesions, with resolution more common among CVS- lesions. The high frequency of confluent or multivein lesions limited the proportion suitable for CVS analysis. MRI timing influenced CVS detection, which was higher in remission, suggesting that time of acquisition contributes to variability across MOGAD studies. No PRLs were found, supporting their potential as biomarkers distinguishing MOGAD from MS.

BACKGROUND AND PURPOSE:The superficial subplate forms the interface between the cortical plate and the deeper subplate, as a transient sublamina prominent during midfetal development of the human brains when many cortical malformations originate, and prenatal counselling is needed. Our aim was to assess the visibility of the superficial subplate throughout development using in vivo 3 Tesla fetal MR images in the human brain. MATERIAL AND METHODS:In this retrospective observational study, 51 human fetuses (19- 36 gestational weeks, GW) medically assessed as neurotypical were imaged on a 3 Tesla MR scanner in vivo, using single shot, fast spin-echo T2-weighted sequences (T2-weighted SSFSE) and images in three planes were selected. Three readers twice assessed the visibility of the sSP on the selected images in the region of frontal, parietal, temporal, and occipital lobes. To explore the relationship between the visibility of the superficial subplate (sSP) and gestational age, regression analysis was used. A quadratic model was applied to investigate the non-linear association between visibility scores and fetal age. The inter-observer agreement on the visibility of sSP was scrutinized both pairwise and among all three raters. Weighted kappa statistics determined inter- and intra-rater agreement. RESULTS:The visualization of the sSP on in vivo fetal 3T MRI was possible between the 19th and 27th weeks of gestation, in one or more lobes, (the frontal, parietal, temporal, occipital), with optimal visibility between 20 and 27 gestational weeks coinciding with the peaks in glycosaminoglycan expression in the sSP. Inter-rater agreement ranged from moderate to excellent (weighted κ = 0.57-0.93), with a mean κ of 0.81 ± 0.10 on first assessment, improving to 0.88 ± 0.03 on second assessment. Intra-rater agreement was good to excellent (κ = 0.75-0.90). CONCLUSIONS:The superficial subplate is visible on T2-w in vivo fetal MRI at 3T. A deeper understanding of the in vivo appearance of the laminar organization of the human fetal brain, including the superficial subplate, is required to accurately interpret altered fetal brain development, thereby improving early diagnostic accuracy, reducing false-positive assessments, and supporting prenatal counselling in cases of suspected cortical malformations.

BACKGROUND AND PURPOSE:Pleomorphic Xanthoastrocytomas (PXAs) are rare pediatric brain tumors accounting for approximately 1% of primary brain neoplasms in children and young adults. Despite recent imaging and molecular advances, gaps remain in our understanding of their diverse imaging characteristics and clinical outcomes. This study provides a large international, multi-institutional analysis of pediatric PXAs focusing on neuroimaging and clinical outcomes. MATERIALS AND METHODS:We conducted a retrospective international multi-center study including 63 pediatric patients with histologically confirmed PXAs. Neuroimaging data were reviewed, and molecular analyses were recorded with emphasis on BRAF V600E mutations and CDKN2A/B deletions. Treatment modalities and clinical outcomes, including progression-free and overall survival, were analyzed using statistical survival models. RESULTS:73.3% of tumors were CNS WHO grade 2 and 26.7% were CNS WHO grade 3. The median age at diagnosis was 10.7 (IQR 6.9) years. CNS WHO grade 3 tumors were significantly larger at diagnosis, with a median volume of 87,920 mm³ compared with 14,925 mm³ for grade 2 tumors (p = 0.03). BRAF V600E mutations were identified in 78% of cases and CDKN2A/B deletions in 93.5%. On MRI, PXAs typically appeared well-defined, with cortical and leptomeningeal contact (86.0% and 56.4%, respectively), frequent cysts (59.6%), and intermediate diffusivity (mean ADC 1005 × 10-6 mm2/s). CT imaging showed most tumors were isointense to gray matter (52.0%), with hydrocephalus more common in grade 3 tumors (71.4% vs. 26.3%, p = 0.07). Gross total resection was achieved in 73.7% of cases and was associated with improved progression-free survival, independent of age at diagnosis and tumor grade (HR = 0.39; 95% CI, 0.16-0.96; p = 0.041). Larger tumor volume correlated with poorer survival outcomes (HR = 3.47; 95% CI, 0.83-14.4; p = 0.087), also independent of tumor grade and age at diagnosis. Tumor recurrence occurred in 44.8% of patients at three years. The estimated three-year overall survival rate was 94.7%. CONCLUSIONS:Pediatric PXAs exhibit distinct neuroimaging and molecular features correlating with prognosis. Integrated evaluation of radiological and clinical features is critical to improve risk stratification and guide personalized therapeutic strategies in this rare tumor population.

The Oligophrenin 1 (OPHN1) gene, located on Xq12, encodes a Rho GTPase-activating protein that regulates the Rho/Ras signalling pathways essential for cell migration, morphogenesis, dendritogenesis, and synaptic plasticity. Pathogenic variants in OPHN1 have been shown to be associated with structural brain malformations. Early neuroimaging reports described nonspecific findings such as an enlarged cisterna magna, ventriculomegaly, and cerebellar hypoplasia, whereas subsequent studies identified more distinctive abnormalities, including frontotemporal volume reduction and caudate head hypoplasia, and vermian and asymmetric cerebellar hypoplasia. In this series, we applied a systematic approach to detailed MRI phenotyping in patients with confirmed OPHN1 variants. We identified a consistent constellation of structural abnormalities, including cerebellar vermian and hemispheric hypoplasia with dysfoliation, brainstem malformations including aberrant tracts such as anterior mesencephalic cap dysplasia, and abnormal transverse pontine fibers; and supratentorial features such as caudate hypoplasia, frontal-predominant ventriculomegaly, and commissural anomalies. Additional findings, such as dysgyria, hippocampal and olfactory bulb abnormalities, optic nerve hypoplasia, cerebellar heterotopia, and cranial mesenchymal anomalies, further expand the recognized phenotype. The combination of gray and white matter involvement, together with DTI evidence of aberrant fibers, supports a pathogenic mechanism involving abnormal regional development, disrupted cerebrocerebellar connectivity, and impaired axonal guidance.

Diffuse midline gliomas (DMGs) are near-universally lethal tumours of the childhood central nervous system1,2. In animal models, DMGs form brain-wide integrated networks through neuron-to-glioma synapses3-6 and glioma-to-glioma gap junctional coupling3. This extensive connectivity robustly promotes the growth and invasion of DMG3-9 and other glial malignancies10-12 through paracrine mechanisms and direct neuron-to-glioma synapses. However, the organization and clinical implications of these connections in the living human brain remain to be elucidated. Here, we develop tumour network mapping to compute the brain-wide connectivity profile of DMG, defining a conserved brain network across pontine and thalamic DMG associated with patient short-term survival (DMG network). Tumour functional connectivity with the DMG network was independently predictive of patient overall survival across two external validation cohorts. Tumour growth mapped to DMG network-specific trajectories and peak in-network neurometabolic changes across development spatiotemporally aligned with the peak age incidence of DMG. Analyses of single-nucleus RNA sequencing data confirmed diverse synaptic gene enrichment in high-connectivity DMG. Strikingly, incidental surgical resection of high-connectivity thalamic DMG tissue conferred a significant survival advantage. Collectively, these data define a conserved and prognostically important brain network in children with DMG, consistent with the hypothesis that DMGs exploit otherwise healthy brain circuits to promote tumour growth.

Artificial intelligence (AI) has potential to revolutionize radiology, yet current solutions and guidelines are predominantly focused on adult populations, often overlooking the specific requirements of children. This is important because children differ significantly from adults in terms of physiology, developmental stages, and clinical needs, necessitating tailored approaches for the safe and effective integration of AI tools. This multi-society position statement systematically addresses four critical pillars of AI adoption: (1) regulation and purchasing, (2) implementation and integration, (3) interpretation and post-market surveillance, and (4) education. We propose pediatric-specific safety ratings, inclusion of datasets from diverse pediatric populations, quantifiable transparency metrics, and explainability of models to mitigate biases and ensure AI systems are appropriate for use in children. Risk assessment, dataset diversity, transparency, and cybersecurity are important steps in regulation and purchasing. For successful implementation, a phased strategy is recommended, involving early pilot testing, stakeholder engagement, and comprehensive post-market surveillance with continuous monitoring of defined performance benchmarks. Clear protocols for managing discrepancies and adverse incident reporting are essential to maintain trust and safety. Moreover, we emphasize the need for foundational AI literacy courses for all healthcare professionals which include pediatric safety considerations, alongside specialized training for those directly involved in pediatric imaging. Public and patient engagement is crucial to foster understanding and acceptance of AI in pediatric radiology. Ultimately, we advocate for a child-centered framework for AI integration, ensuring that the distinct needs of children are prioritized and that their safety, accuracy, and overall well-being are safeguarded.

This narrative review maps the current landscape of artificial intelligence (AI) in paediatric and fetal neuroradiology, critically evaluating current practice, barriers to clinical adoption, and future potential. We searched for peer-reviewed studies from the last decade, focusing on image segmentation, lesion detection, classification, prognostication, and clinical decision support in paediatric brain imaging. Particular consideration was given to unique paediatric factors such as brain development and data scarcity. AI techniques, notably deep learning, have demonstrated success in automated brain tumour segmentation, detection of epileptogenic lesions, and radiomics-based classifiers predicting tumour histology and molecular subtypes. Despite these advancements, clinical adoption remains limited. Key barriers identified include high implementation costs, limited large-scale diverse paediatric datasets, and concerns regarding safety, bias, and regulatory approval. Addressing these issues through data-sharing initiatives, federated learning, paediatric-specific validation, and revised ethical and regulatory frameworks is crucial. Ongoing multi-institutional collaborations can facilitate AI’s integration into paediatric neuroradiology, complementing radiologists and improving paediatric care.

Magnetic resonance imaging (MRI) is essential for post-treatment surveillance of patients with intracranial central nervous system (CNS) tumours. However, interpretation is often complicated due to post radiotherapy MRI abnormalities. Current literature demonstrates substantial heterogeneity in terminology and definitions used to describe these MRI abnormalities, limiting clinical decision-making and comparability across studies. To address this, an international multidisciplinary Delphi consensus was conducted within the Radiation Imaging and Neuro-Oncology Group (RING). Questionnaires were developed by the steering committee and distributed to experts in radiation oncology, neuroradiology, neuro-oncology, medical oncology, and neurosurgery. A three-round Delphi method was employed, with consensus defined as ≥ 75% agreement. Consensus was reached on the applicability and definitions with adoption of the term Treatment-Related Imaging Abnormality (TRIA). Clear definitions for potential and confirmed TRIA were established. Subcategorization based on imaging features all demonstrated high agreement. For consistent application of the framework minimal essential elements for MRI request forms were identified. The final consensus was endorsed by ESTRO, ESNR and EORTC. This Delphi consensus provides a standardized framework for MRI abnormalities following radiotherapy for intracranial CNS tumours. The framework aims to harmonize reporting, support clinical decision-making, and improve comparability in future neuro-oncology research. Central nervous system neoplasms - Radiotherapy - Magnetic resonance imaging - Delphi Technique - Treatment-Related Imaging Abnormality (TRIA).