Focal cortical dysplasia (FCD) is the leading cause of drug-resistant epilepsy (DRE) in pediatric patients. Accurate detection of FCDs is crucial for successful surgical outcomes, yet remains challenging due to frequently subtle MRI findings, especially in children, whose brain morphology undergoes significant developmental changes. Automated detection algorithms have the potential to improve diagnostic precision, particularly in cases, where standard visual assessment fails. This study aimed to evaluate the performance of automated algorithms in detecting FCD type II in pediatric patients and to examine the impact of adult versus pediatric templates on detection accuracy. MRI data from 23 surgical pediatric patients with histologically confirmed FCD type II were retrospectively analyzed. Three imaging-based detection algorithms were applied to T1-weighted images, each targeting key structural features: cortical thickness, gray matter intensity (extension), and gray-white matter junction blurring. Their performance was assessed using adult and pediatric healthy controls templates, with validation against both predictive radiological ROIs (PRR) and post-resection cavities (PRC). The junction algorithm achieved the highest median dice score (0.028, IQR 0.038, p < 0.01 when compared with other algorithms) and detected relevant clusters even in MRI-negative cases. The adult template (median dice score 0.013, IQR 0.027) significantly outperformed the pediatric template (0.0032, IQR 0.023) (p < 0.001), highlighting the importance of template consistency. Despite superior performance of the adult template, its use in pediatric populations may introduce bias, as it does not account for age-specific morphological features such as cortical maturation and incomplete myelination. Automated algorithms, especially those targeting junction blurring, enhance FCD detection in pediatric populations. These algorithms may serve as valuable decision-support tools, particularly in settings where neuroradiological expertise is limited.

• Keywords
• Cortical thickness, Focal cortical dysplasia type II, Gray-white matter blurring, Neuroimaging, Pediatric epilepsy,
• Publication type
• Journal Article MeSH

OBJECTIVE: We comprehensively characterized a large pediatric cohort with focal cortical dysplasia (FCD) type 1 to expand the phenotypic spectrum and to identify predictors of postsurgical outcomes. METHODS: We included pediatric patients with histopathological diagnosis of isolated FCD type 1 and at least 1 year of postsurgical follow-up. We systematically reanalyzed clinical, electrophysiological, and radiological features. The results of this reanalysis served as independent variables for subsequent statistical analyses of outcome predictors. RESULTS: All children (N = 31) had drug-resistant epilepsy with varying impacts on neurodevelopment and cognition (presurgical intelligence quotient [IQ]/developmental quotient scores = 32-106). Low presurgical IQ was associated with abnormal slow background electroencephalographic (EEG) activity and disrupted sleep architecture. Scalp EEG showed predominantly multiregional and often bilateral epileptiform activity. Advanced epilepsy magnetic resonance imaging (MRI) protocols identified FCD-specific features in 74.2% of patients (23/31), 17 of whom were initially evaluated as MRI-negative. In six of eight MRI-negative cases, fluorodeoxyglucose-positron emission tomography (PET) and subtraction ictal single photon emission computed tomography coregistered to MRI helped localize the dysplastic cortex. Sixteen patients (51.6%) underwent invasive EEG. By the last follow-up (median = 5 years, interquartile range = 3.3-9 years), seizure freedom was achieved in 71% of patients (22/31), including seven of eight MRI-negative patients. Antiseizure medications were reduced in 21 patients, with complete withdrawal in six. Seizure outcome was predicted by a combination of the following descriptors: age at epilepsy onset, epilepsy duration, long-term invasive EEG, and specific MRI and PET findings. SIGNIFICANCE: This study highlights the broad phenotypic spectrum of FCD type 1, which spans far beyond the narrow descriptions of previous studies. The applied multilayered presurgical approach helped localize the epileptogenic zone in many previously nonlesional cases, resulting in improved postsurgical seizure outcomes, which are more favorable than previously reported for FCD type 1 patients.

• Keywords
• drug‐resistant epilepsy, epilepsy surgery, focal cortical dysplasia type 1, multilayered diagnostic protocol, pediatric patients,
• MeSH
• Child MeSH
• Electroencephalography MeSH
• Focal Cortical Dysplasia MeSH
• Cohort Studies MeSH
• Infant MeSH
• Humans MeSH
• Magnetic Resonance Imaging MeSH
• Malformations of Cortical Development, Group I * complications   surgery   physiopathology   diagnostic imaging   MeSH
• Adolescent MeSH
• Follow-Up Studies MeSH
• Positron-Emission Tomography MeSH
• Child, Preschool MeSH
• Drug Resistant Epilepsy * surgery   diagnostic imaging   physiopathology   etiology   MeSH
• Treatment Outcome MeSH
• Check Tag
• Child MeSH
• Infant MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Child, Preschool MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

BACKGROUND: We aimed first to describe trends in cognitive performance over time in a large patient cohort (n = 203) from a single tertiary centre for paediatric epilepsy surgery over the period of 16 years divided in two (developing-pre-2011 vs. established-post-2011). Secondly, we tried to identify subgroups of epilepsy surgery candidates with distinctive epilepsy-related characteristics that associate with their pre- and post-surgical cognitive performance. Thirdly, we analysed variables affecting pre-surgical and post-surgical IQ/DQ and their change (post- vs. pre-surgical). METHODS: We analysed IQ/DQ data obtained using standardized neuropsychological tests before epilepsy surgery and one year post-surgically, along with details of patient's epilepsy, epilepsy surgery and outcomes in terms of freedom from seizures. Using regression analysis, we described the trend in post-operative IQ/DQ. Cognitive outcomes and the associated epilepsy- and epilepsy surgery-related variables were compared between periods before and after 2011. Using multivariate analysis we analysed the effect of individual variables on pre- and post-operative IQ/DQ and its change. RESULTS: Epilepsy surgery tends to improve post-surgical IQ/DQ, most significantly in patients with lower pre-surgical IQ/DQ, and post-surgical IQ/DQ strongly correlates with pre-surgical IQ/DQ (Rho = 0.888, p < 0.001). We found no significant difference in pre-, post-surgical IQ/DQ and IQ/DQ change between the periods of pre-2011 and post-2011 (p = 0.7, p = 0.469, p = 0.796, respectively). Patients with temporal or extratemporal epilepsy differed in their pre-surgical IQ/DQ (p = 0.001) and in IQ/DQ change (p = 0.002) from those with hemispheric epilepsy, with no significant difference in post-surgical IQ/DQ (p = 0.888). Groups of patients with different underlying histopathology showed significantly different pre- and post-surgical IQ/DQ (p < 0.001 and p < 0.001 respectively) but not IQ/DQ change (p = 0.345).Variables associated with severe epilepsy showed effect on cognitive performance in multivariate model. DISCUSSION: Post-surgical IQ/DQ strongly correlates with pre-surgical IQ/DQ and greatest IQ/DQ gain occurs in patients with lower pre-surgical IQ/DQ scores. Cognitive performance was not affected by changes in paediatric epilepsy surgery practice. Pre- and post-operative cognitive performances, as well as patients' potential for cognitive recovery, are highly dependent on the underlying aetiology and epileptic syndrome.

• Keywords
• Cognitive outcome, Drug resistant epilepsy, Long-term epilepsy-associated tumours, Malformations of cortical development, Paediatric epilepsy surgery,
• Publication type
• Journal Article MeSH

Malformations of cortical development (MCD) comprise a broad spectrum of developmental brain abnormalities. Patients presenting with MCDs often suffer from drug-resistant focal epilepsy, and some become candidates for epilepsy surgery. Their likelihood of achieving freedom from seizures, however, remains uncertain, and depends in a major part on the underlying pathology. Tissue samples obtained in epilepsy surgery form the basis of definite histopathological diagnosis; however, new molecular genetic methods have not yet been implemented in diagnostic processes for MCD cases. Furthermore, it has not been completely understood how the underlying pathology affects patients' outcomes after epilepsy surgery. We performed a systematic literature review of studies describing both histopathological and molecular genetic findings in MCD, along with studies on epilepsy surgery outcomes. We aimed to correlate the genetic causes with the underlying morphological abnormalities in focal cortical malformations and to stress the importance of the underlying biology for patient management and counseling. From the summarized findings of multiple authors, it is obvious that MCD may have a diverse genetic background despite a similar or even identical histopathological picture. Even though most of their molecular genetic findings converge on various levels of the PI3K/AKT/mTOR pathway, the exact mechanisms underlying MCD formation have not yet been completely described or indeed how this pathway generates a diverse range of histological abnormalities. Based on our findings, we therefore propose that all patients diagnosed and operated for drug-resistant epilepsy should have an integrated molecular and pathological diagnosis similar to the current practice in brain tumor diagnostic processes that might lead to more accurate diagnosis and effective stratification of patients undergoing epilepsy surgery.

• Keywords
• mTOR, epilepsy surgery, malformations of cortical development, neuropathology, somatic variant,
• MeSH
• Epilepsy genetics   pathology   MeSH
• Phosphatidylinositol 3-Kinases MeSH
• Genetic Association Studies MeSH
• Humans MeSH
• Malformations of Cortical Development genetics   pathology   MeSH
• Brain abnormalities   pathology   MeSH
• Cerebral Cortex pathology   MeSH
• Brain Diseases pathology   MeSH
• Drug Resistant Epilepsy genetics   pathology   MeSH
• Signal Transduction MeSH
• TOR Serine-Threonine Kinases MeSH
• Seizures pathology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Systematic Review MeSH
• Names of Substances
• TOR Serine-Threonine Kinases MeSH

Focal cortical dysplasias (FCDs) are a range of malformations of cortical development each with specific histopathological features. Conventional radiological assessment of standard structural MRI is useful for the localization of lesions but is unable to accurately predict the histopathological features. Quantitative MRI offers the possibility to probe tissue biophysical properties in vivo and may bridge the gap between radiological assessment and ex-vivo histology. This review will cover histological, genetic and radiological features of FCD following the ILAE classification and will explain how quantitative voxel- and surface-based techniques can characterise these features. We will provide an overview of the quantitative MRI measures available, their link with biophysical properties and finally the potential application of quantitative MRI to the problem of FCD subtyping. Future research linking quantitative MRI to FCD histological properties should improve clinical protocols, allow better characterisation of lesions in vivo and tailored surgical planning to the individual.

• Keywords
• Biophysical tissue properties, Epilepsy surgery, Focal cortical dysplasia, Histology, MRI, Malformation of cortical development, Quantitative MRI, Quantitative mapping, Radiology, qMRI,
• MeSH
• Phenotype * MeSH
• Humans MeSH
• Magnetic Resonance Imaging methods   statistics & numerical data   MeSH
• Malformations of Cortical Development diagnostic imaging   genetics   pathology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Review MeSH