Laminar Pattern Disruption in fetal incipient polymicrogyria: Insights from Post-Mortem MR Imaging and Neuropathological Correlation

Laminar Pattern Disruption in fetal incipient polymicrogyria: Insights from Post-Mortem MR Imaging and Neuropathological Correlation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Laminar Pattern Disruption in fetal incipient polymicrogyria: Insights from Post-Mortem MR Imaging and Neuropathological Correlation Giana Izzo, Mario Tortora, Valentina Toto, Mariano Lanna, Chiara Doneda, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9506392/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract Background Polymicrogyria (PMG) is a heterogeneous cortical malformation resulting from disruption of multiple processes of cortical development, either genetically or clastic determined. Objective To characterize early imaging and histopathological features of incipient PMG in fetuses at early gestational age and correlate radiological patterns with underlying etiopathogenic mechanisms. Materials and methods Four fetuses at 21 weeks’ gestational age (GA) with suspected PMG on fetal MRI underwent post-mortem MRI (pmMRI) and detailed neuropathological examination, including immunohistochemistry (NeuN, GFAP, MBP, CD3, CD68). Imaging and histological findings were systematically compared. Results Distinct imaging–histopathological patterns were identified according to etiology (ischemic, infectious, genetic). Key differentiating features included symmetry of involvement, cerebral surface appearance, integrity of the pial basement membrane, laminar pattern alterations and associated anomalies. Conclusion Combined pmMRI and neuropathology enable early characterization of PMG and provide insights into its etiopathogenesis, improving differential diagnosis and genetic counseling. Polymicrogyria fetal MRI post-mortem MRI cortical development neuropathology Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Polymicrogyria (PMG) represents a spectrum of cortical malformations characterized by excessive small gyri and abnormal cortical lamination [ 1 – 2 ]. It is increasingly recognized as a final common pathway of multiple developmental insults rather than a single disease entity [ 3 – 4 ]. The pathogenesis of PMG is heterogeneous and includes genetic mutations, intrauterine infections (particularly cytomegalovirus), vascular insults and metabolic disturbances [ 5 – 8 ]. These mechanisms interfere with critical stages of corticogenesis, including neuronal proliferation, migration, and cortical organization [ 9 – 10 ]. Normal cortical development between 20- and 24-weeks of gestation is characterized by a well-defined transient laminar structure, reflecting coordinated neuronal migration and radial glial scaffolding [ 11 – 12 ]. Precocious disruption of these processes can lead to abnormal cortical folding and lamination, as seen in PMG [ 13 ]. Recent advances in fetal MRI (fMRI) and especially high-resolution post-mortem MRI (pmMRI) have significantly improved the ability to detect early cortical abnormalities [ 14 – 17 ]. pmMRI, with its superior spatial resolution, allows detailed visualization of transient fetal lamination (Fig. 1 ) and subtle cortical abnormalities that are often not appreciable in vivo [ 18 ]. Neuropathological studies have highlighted the importance of the integrity of the cortical surface and in particular the role of the pial basement membrane (PBM) and radial glial anchorage in normal corticogenesis [ 19 ]. Disruption of this interface has been identified as a key mechanism in several forms of PMG, particularly those associated with overmigration disorders [ 20 – 22 ]. In this study, we aim to correlate early imaging findings with histopathological features in a series of fetuses with incipient PMG, to identify imaging biomarkers that reflect distinct etiopathogenic mechanisms. Material and methods Patients’ data We retrospectively analyzed four fetuses at 21 weeks’ GA referred for suspected cortical malformation based on fMRI. Following multidisciplinary counseling, termination of pregnancy (TOP) was performed in all cases. Parental consent was obtained for post-mortem imaging and neuropathological examination. The fetuses were stored at 4–5 °C and underwent pmMRI within 24 hours after delivery, scanned fresh. Subsequently, complete neuropathological examination was performed. Cases were selected to represent distinct etiopathogenic categories of PMG, including ischemic, infectious, and genetic forms, as well as a spectrum of radiological and anatomical presentations. MRI methods Prenatal MRI examinations were performed on a 1.5-T system (Ingenia, Philips Medical Systems, Best, the Netherlands). The imaging protocol included multiplanar T2-weighted single-shot fast spin-echo sequences with a slice thickness of 3 mm and an in-plane resolution of approximately 1 mm², complemented by balanced steady-state free precession sequences, T1-weighted fast spin-echo sequences, and axial diffusion-weighted imaging (DWI). Post-mortem MRI was performed on the same 1.5-T system using either a dedicated neonatal head coil or the smallest available coil adapted to fetal size. In selected cases, saline bags were positioned within the coil to improve signal homogeneity. The imaging protocol included high-resolution T2-weighted fast spin-echo sequences with a slice thickness of 2 mm and an in-plane resolution of approximately 0.3 mm², as well as three-dimensional turbo spin-echo T1-weighted sequences and axial DWI. This approach enabled detailed visualization of transient fetal brain lamination and subtle cortical abnormalities. Neuropathology Brain extraction and fixation were performed according to Gilbert-Barness protocol [23]. After fixation, standardized sampling included three coronal sections at predefined levels from the frontal to occipital lobes in both hemispheres and three horizontal sections extending from the mesencephalon to the medulla oblongata. Tissue samples were embedded in paraffin and stained with hematoxylin-eosin for routine histological assessment. Representative sections were selected for immunohistochemical analysis using antibodies against neuronal nuclear antigen (NeuN) (NeuN- clone A60-Dako; 1:100), glial fibrillary acidic protein (GFAP) (GFAP- ready to use polyclonal-Dako), CD34 (QBEND10 clone-Dako; 1:100) and neuron-specific enolase (NSE) (BBS-NC-VI clone-Dako; 1:100). Immunohistochemistry was performed using DAKO-Omnis following the standard automatic protocol. Image and histopathological analysis PmMRI datasets were reviewed and systematically correlated with histopathological findings. Attention was paid to cortical plate thickness and morphology, presence of extracortical tissue or neurons overmigration, appearance of the pial surface and PBM integrity, alteration of the other parenchimal layers, and associated supratentorial and infratentorial anomalies. Comparative analysis between prenatal MRI, post-mortem MRI, and histology was performed to identify imaging correlates of specific etiopathogenic mechanisms. In Fig. 1 is reported an exemplificative case of normal appearance of cerebral surface and cerebral laminar pattern by multimodal post-mortem imaging and histopathological correlation in a 21 GA normal ex fetu. Ethical statement All procedures performed in the studies involving human participants were in accordance with the 1964 Helsinki Declaration.The cases were recruited as clinical cases with ethical approval for retrospective review of clinical notes and MR images by the “Milano Area 1” Ethics Committee (n. 27757/2022 protocol approval code). Informed consent was obtained from all individual participants included in the study. The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Results Overview All cases demonstrated abnormalities of cortical development that were more clearly appreciable on post-mortem MRI than on prenatal imaging. Distinct patterns emerged according to the underlying etiology, particularly regarding the symmetry of cortical involvement, the appearance of cerebral surface, the integrity of the PBM, the presence of inflammatory changes, degree and pattern of laminar disruption, and associated structural abnormalities. Ischemic PMG secondary to Twin-to-Twin Transfusion Syndrome (TTTS); Fig. 2. This case involved a PMG associated with infarction in the territory of the middle cerebral artery in an ex-co-twin, after death of the donor as a complication of twin-to-twin transfusion syndrome (TTTS) treated with laser therapy. In-vivo imaging showed a clear reduction in the volume of one hemisphere, consistent with tissue loss. Coronal sections highlighted an associated irregularity of the cortical plate in perisylvian fronto-parietal areas with a “wartlike” appearance, as described in [24]. PmMRI further elucidated this cortical anomaly: the cortical plate showed a wavy appearance and irregular thickening that appears to extend beyond its expected boundary. The subplate was also markedly reduced. Immuno-Histological sections confirmed what was observed on pm-MRI. GFAP staining demonstrated the classic festooned appearance of the cerebral surface seen in PMG. In the higher-magnification images, foci of laminar necrosis and a micro-regional alteration of the PBM were evident, along with leptomeningeal thickening related to the presence of extrapial ectopic neurons and glial cells associated with macrophages infiltrate and meningeal vessels proliferation. Reactive gliosis in the marginal zone and subplate was also evident. PMG due to Congenital Cytomegalovirus (CMV) Infection; Fig. 3. In the second scenario, PMG developed following intrauterine cytomegalovirus (CMV) infection, a known cause of cortical malformation development due to its specific tropism for radial glial progenitor cells. In-vivo imaging was instrumental in identifying early signs of this disruption; on axial fetal scans, there was a mild asymmetry in parenchymal thickness with enlargement of the lateral ventricle in the smaller hemisphere. On that side a subtle irregularity along the cortical plate was evident raising suspicion of a cortical developmental anomaly. Even DWI showed an asymmetric restriction of water diffusion along the cortical plate between the two hemispheres, more prominent/severe in the smaller hemisphere. This suggested an asynchronous involvement of the two hemispheres, with a manifest appearance in one hemisphere and evidence of a still ongoing infective process on the other side. PmMRI clarified the pre-natal cerebral findings. In the smaller hemisphere there was an already established PMG pattern, with a thickened and irregular cortical plate characterized by excessive abnormal small cerebral gyri, indistinct subplate, reduction of intermediate zone and disruption of the germinal zone. A T2 markedly hypointense rim along the cortical ribbon was also evident, possibly reflecting laminar necrosis and calcium deposits, probably corresponding to the areas of prominent diffusion restriction on in-vivo imaging. On the opposite, the other hemisphere (on the radiological right in Fig.2) demonstrated an earlier stage of the parenchymal infectious involvement with overall increasing of T2 weighted signal of cerebral layers due to edema; in particular the cortical plate was thickened with evidence of an outer extracortical layer, and inwards it appeared poorly distinguishable from the subplate, with undulating appearance of thalami-cortical fibers, the thin linear layer located in the upper portion of the subplate just below the lower portion of the cortical plate. Histopathology confirmed these MRI features. Immunohistochemical stains revealed a diffuse disorganization of the laminar pattern on both sides, with festooning appearance of the cortical plate at multiple sites of the left hemisphere consisting with polimicrogyria. NeuN stains showed bilateral cells rarefaction at the level of the periventricular germinal matrix as well as in the cortical plate and subplate, more evident in the left hemisphere. GFAP staining corroborated the NeuN findings, also demonstrating the profound derangement of the glial scaffold in the intermediate zone of both sides with intense reactive gliosis in the subplate and marginal zone of the left hemisphere. This glial response was consistent with chronic neuroinflammatory activity. Alike, leptomeningeal thickening was observed due to neovascularization and macrophages inflammatory infiltration at CD3 stains. Worthy of note, the MBP was preserved. CD8 and CD3 staining respectively identified extensive lympho-macrophagic infiltration within the cortical plate and subplate as well as in the periventricular zone, more evident on the left side, confirming CMV’s tropism for stem cells and radial glial progenitors in the subventricular zone (SVZ). The microscopic differences between the two hemispheres mirror the asynchronous bilateral injury seen on imaging and illustrates how the virus not only interferes with cortical lamination but also induces a neuroinflammatory cascade that shapes the evolving morphology of the developing brain. Post-mortem MRI T2-weighted coronal (c) and axial images (d) depict an established cortical PMG pattern in the smaller hemisphere (on the left), with cortical plate thickening, blurring and thinning of the intermediate zone and subplate, and involvement of germinal layers. The cortical plate appears marked hypointense, probablycorresponding to the stronger cortical diffusion restriction on that side seen in b, probably due to calcifications and laminar necrosis. The contralateral hemisphere represents an earlier stage, characterized by irregular cortical plate thickening and indistinguishable from the subplate, overall parenchymal swelling and hyperintensity, due to edema. At magnification image (e), note the undulation of the upper subplate layer corresponding to thalamo-cortical fibers, suggesting early cortical folding disturbance. At histopathology, NeuN staining images (f-h) confirm overt cortical “festooning” in the left hemisphere and cortical plate thickening and irregularity on the right side; in particular, high-magnification views (g-h) highlight the bilateral, diffuse cortical disorganization, derangement and cells rarefaction involving the wall layers, including those periventricular. These findings are more evident on the left hemisphere, consistent with stage-dependent CMV-related cortical injury. Left hemisphere GFAP high magnification stains (i,l) demonstrate multiple foci of gliosis (colored in brown, arrows) within the subplate and the marginal zone. On the higher magnification image (l) the PBM appears intact and leptomeningeal thickening is evident due to neovascularization phenomena and macrophages infiltrations, as seen at high magnification image CD3 stain (m). CD8 (n) and CD3 (o) staining respectively identified extensive lympho-macrophagic infiltration within the cortical plate and subplate as well as in the periventricular zone. PMG with Hemimegaloencephaly due to PIK3CA Mutation; Fig. 4. The third fetus showed unilateral PMG associated with hemimegalencephaly, genetically related to the PIK3CA gene mutation. This condition represents a classic example of cortical malformation driven by overgrowth syndromes. The fetal MRI clearly demonstrated marked hemispheric asymmetry, with the affected hemisphere appearing enlarged and displaying irregularity of the cortical plate. Even the laminar pattern was asymmetric either in layering, with intermediate zone and subplate expansion, and in signal, with an overall reduced T2 signal, suggesting the presence of higher cellularity within every layers. Post-mortem MRI provided further detail, benefiting from higher spatial resolution. The cortical surface was slightly thickened with a polymicrogyric appearance; the intermediate zone and even more the subplate were abnormally thick with respect to the other hemisphere and their boundaries appeared blurred. Importantly, the usual demarcation of the thalamocortical fibers within the outer subplate was no longer visible, indicating disruption of normal cortical-subcortical connectivity. The whole layers T2 signal was confirmed to be reduced, for the reasons mentioned above. Histological analysis confirmed the imaging findings. Immunohistochemical staining for NeuN revealed an increased number of mature neurons in the superficial cortical layers, consistent with an aberrant cortical lamination pattern with inversion of the normal inside-out cortical proliferation with eventual premature folding. Despite these profound alterations in cortical architecture, both the PBM and the leptomeninges appeared intact, excluding a disruption of pial structures as a contributing factor. GFAP staining was normal, suggesting an absence of significant reactive gliosis. The hallmark features here—festooning of the cortical plate, expansion of the intermediate and subplate zone, loss of subplate architecture, and inverted neuronal cortical layering—point toward a pathogenesis driven by hyperactivation of the PI3K-AKT signaling pathway. GPR56-Related PMG with Cobblestone-Like Features; Fig. 5. The fourth case involved a fetus with bilateral frontoparietal PMG caused by a mutation in the GPR56 gene, encoding a receptor complex expressed on the end feet of radial glial cells that mediate anchorage to the PBM. Fetal MRI showed some irregularities along the cortical rim with focal bump appearance in frontal lobes associated to probable small subependymal heterotopic nodules. On sagittal sections, cerebellar hypoplasia was also noted. These findings suggested a complex early structural alteration involving both supratentorial and sub tentorial structures. Post-mortem MRI further clarified the malformation pattern. The cortical plate was markedly irregular and thick, with evidence of an outer layer beyond the T2 hypointense cortical rim associated to focal areas where this contour appeared interrupted with distinct cortical protrusion, giving rise to cobblestone-like appearance of the cortical surface. This pattern was particularly striking at the frontal vertex, while in the parietal regions a pattern like the PMG one was appreciable. An abnormal subplate and intermediate zone representation (reduced in thickness and blurred) was also evident, as markers of complex anomaly of the fetal cerebrum development. Histological examination confirmed these observations, demonstrating a complex cortical malformation pattern where PMG aspects and cobblestone-like features were merged. Histopathologically, cobblestone cortex anomaly typically consists in complete disorganization of the cortical plate with lack of normal laminar stratification, confirmed by a randomly distributed NeuN reactivity along the whole thickness of the cortical plate. In addition, GFAP staining demonstrated the discontinuity of the PBM at multiple sites, with cortical plate indistinguishable from the leptomeningeal space, associated to extrapial neuronal heterotopy and focal entrapment of meningeal vessels within the subplate was also evident at CD34 staining; a complete glial scaffold derangement was also present. On the contrary hallmark features of PMG consisted in cortical festooning bands organization of neurons and the presence of the entrapment of large vessels within fused sulci at CD34 staining. GFAP staining also demonstrated the presence of sparse glial cells in the subpial zone, extending through the superficial cortex. These findings aligned with the imaging features. Unlike typical PMG, GPR56-related malformations exhibit a mixed pattern of PMG and cobblestone dysplasia, cerebellar involvement, and an absence of clear cortical lamination, where the breakdown of the glia-pial anchorage plays a pivotal role. Discussion In our series, we illustrated the morphological appearance of incipient PMG related to different pathogenetic pathways, each producing a characteristic morphological and histopathological profile, by using the correlation between high-resolution post-mortem imaging and immunohistopathology. With the development of MRI techniques, the image quality of in vivo fetal MRI has greatly improved; however, its diagnostic ability to demonstrate early anomalies of cortical development remains limited by sequence characteristics and magnetic field strength, such that it cannot clearly depict subtle changes in parenchymal stratification [25]. In our cases, fetal MRI only demonstrated irregularity of the cortical plate, eventually associated with volumetric reduction of the involved cerebral parenchyma. On the contrary, post-mortem MRI, also due to its higher in-plane resolution (approximately four times higher than fetal MRI), can clearly depict subtle changes in cerebral lamination suggestive of early disruption of cortical developmental processes, revealing precise correlations with findings observed in histological sections [26]. Similar results have been reported by Kang et al., comparing 1.5 T and 3 T modalities in terms of tissue contrast, diagnostic error, and diagnostic accuracy in post-mortem brain evaluation [14]. Transient lamination of the fetal cerebrum is normally observed between 20 and 24 weeks of gestation and represents a marker of normal cerebral development, reflecting changes in cellularity, fiber organization, neuronal migration, and cortical organization processes [15-16]. The development of a normal cortical sulcal and gyral pattern depends on the successful generation of neuroblasts in the germinal matrix, their migration to the cortical surface along the radial glial scaffold, and their proper organization within the developing cerebral cortex. Proper neuronal migration and laminar positioning are supported by the anchorage of radial glial processes to the pial basement membrane through receptors located on their end feet. Primitive leptomeninges and pial cells also stabilize the pial basement membrane, playing a crucial role in maintaining the integrity of the cortical surface and overall cortical organization. The importance of brain surface integrity for normal corticogenesis has been demonstrated in both experimental and human studies; in large series of fetal PMG at early gestational age, pial defects and neuronal over migration have been observed in a high proportion of cases, regardless of genetic or acquired origin [18,19]. All these steps are tightly coordinated in space and time. Therefore, a pathological process interfering with one of these mechanisms can secondarily disrupt the others. For example, abnormalities in neuronal migration are commonly associated with altered sulcation and gyration patterns, and vice versa. Based on this, disruption of the expected appearance and signal intensity within cerebral lamination on post-mortem MRI can be considered an early indicator of abnormal cortical development, as confirmed in our series. Moreover, in our cases, post-mortem MRI, corroborated by histopathology, demonstrated specific features useful for distinguishing different pathogenic pathways. In ischemic PMG, the prototypical pattern is characterized by marked asymmetry in cortical involvement, depending on the vascular territory, and by a temporal relationship with the ischemic event. Imaging and histopathological findings included the presence of an extracortical layer due to thickening of the meningeal layers associated with extrapial ectopic neurons and glial cells, macrophage infiltration, and vascular proliferation related to focal disruption of the pial basement membrane. Signs of cortical laminar necrosis were also evident. The laminar pattern was locally altered, with marked reduction of the subplate and associated gliosis. These findings confirm the deleterious impact of acute, regionally selective vascular insults on corticogenesis, as also demonstrated in previous neuropathological studies [21, 27]. Importantly, in this context, the timing of the insult was known, as imaging was performed approximately two weeks after laser therapy, allowing us to confidently identify this pattern as incipient PMG secondary to a vascular event [28]. In PMG caused by congenital cytomegalovirus infection, a different spectrum of cerebral abnormalities was observed, as this viral insult disrupts both neuronal and glial progenitors, resulting in combined periventricular and cortical injury with a typically bilateral distribution. In our case, imaging demonstrated bilateral involvement with an asynchronous pattern typical of early infection, with one hemisphere showing established PMG with cortical calcifications and parenchymal volume loss, and the contralateral hemisphere showing features of an ongoing infective process. The latter represents a prototype of early infection-related cortical malformation, characterized by irregular leptomeningeal and cortical thickening, indistinct cortical–subplate boundaries, and germinal zone injury, with overall parenchymal T2 hyperintensity and swelling reflecting edema, inflammation, and active tissue disorganization. A key observation was the undulating appearance of thalamocortical fibers within the upper subplate, like the cortical plate was crumpling up on the upper part of the subplate, reflecting disruption of the interface between the cortical plate and subplate, and highlighting the crucial role of the subplate in cortical folding and organization [29]. Neuropathological analysis confirmed these findings and demonstrated preservation of the pial basement membrane, in contrast to ischemic forms. These features underline the tropism of cytomegalovirus for progenitor cells in the germinal zone and its disruptive effect on cortical development through inflammation, cell death, and laminar disorganization [30-33]. In contrast, genetic forms of PMG lack of the constellation of features typically observed in acquired (clastic) forms and instead show distinct patterns depending on the underlying mutation. However, a single PMG phenotype may arise from different genetic etiologies, and conversely, the same genetic mutation may produce variable imaging patterns [34]. In the case of PMG associated with hemimegalencephaly due to PIK3CA mutation, post-mortem MRI demonstrated an asymmetric laminar pattern characterized by expansion of the intermediate zone and subplate, blurring of their boundaries, and globally reduced T2 signal intensity, suggesting increased cellularity across all layers and reflecting extensive structural disorganization. The cortical plate was mildly thickened with a wavy appearance, without evidence of an extracortical layer. Histologically, the PBM and leptomeninges were preserved, and no inflammatory changes or gliosis were observed. Conversely, an increased number of mature neurons in superficial cortical layers was identified, consistent with an inverted laminar organization. This abnormal distribution reflects a fundamental disturbance in neuronal migration and positioning, with consequent alteration of radial connectivity and tangential cortical growth processes that normally drive gyration. These findings are consistent with hyperproliferation, and impaired apoptosis of neuronal progenitors related to PI3K-AKT pathway activation [35-36]. The second genetic case involved bilateral frontal-parietal PMG due to GPR56 mutation. This case has been previously reported by us as general features, but as a single isolated entity and not compared and discussed with other forms of PMG as in the present context [37]. This condition provides further insights into the developmental mechanisms underlying PMG, as it results from failure of glial–pial anchorage due to defective interaction between radial glial endfeet and the PBM. This leads to disruption of the glial scaffold, focal breaks in the PBM, and secondary neuronal overmigration during critical stages of brain development, ultimately resulting in abnormal cortical organization and folding. The characteristic imaging and histopathological findings in our case included the coexistence of polymicrogyria in parietal regions and cobblestone-like cortex in frontal regions, with extracortical protrusions related to neuronal and glial overmigration through defects in the PBM. Abnormal representation of the subplate and intermediate zone was also observed, reflecting disruption of the glial scaffold necessary for normal laminar organization. This process is now considered within the spectrum of cobblestone-like cortical malformations due to shared pathogenetic mechanisms with dystroglycanopathies [38] Collectively, these cases illustrate the morphological continuum of PMG as shaped by different developmental insults. Rather than representing a single disease entity, PMG should be considered a convergent endpoint of multiple pathogenic processes affecting cortical development, each characterized by distinct molecular, structural, and temporal features. A unifying concept emerging from both imaging and histopathology is the central role of the pial surface and its integrity in orchestrating normal corticogenesis. Conclusions PMG is not a single entity but a spectrum of cortical malformations reflecting diverse developmental disturbances. The integration of pmMRI and neuropathology allows early identification of etiological patterns, improving diagnostic accuracy and counseling for possible further pregnancies. 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J Biol Chem 286:14215–14225 Additional Declarations No competing interests reported. Supplementary Files GraphicalAbstract.tiff.png Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 19 May, 2026 Reviews received at journal 06 May, 2026 Reviewers agreed at journal 03 May, 2026 Reviewers agreed at journal 28 Apr, 2026 Reviewers invited by journal 28 Apr, 2026 Editor assigned by journal 27 Apr, 2026 Submission checks completed at journal 27 Apr, 2026 First submitted to journal 23 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9506392","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":633564720,"identity":"19aeb3de-97d7-4820-ac82-8ce6e9f33a53","order_by":0,"name":"Giana Izzo","email":"","orcid":"","institution":"Ospedale dei Bambini Vittore Buzzi","correspondingAuthor":false,"prefix":"","firstName":"Giana","middleName":"","lastName":"Izzo","suffix":""},{"id":633564721,"identity":"7b6cc083-1af6-4f0f-87cf-5bcdb8fd8563","order_by":1,"name":"Mario Tortora","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2UlEQVRIiWNgGAWjYJCCAwhmBQMDG4hOIKzFAKr0DEwLIT1wLYxtMAE8WnTbzz488IHhj5z5/OZjH37OO5zHJ938gOHhD9xazM6kGxycwWBgLHOMLXlm77bDxWwyxwzwOszsQBrDYR4Gg8QZbDzGDLzbDie2SSQQ0HL+GUIL4985IC3pH/BruYFkCzNvA0hLDgFbbjxjODjDwNhYgi0tmVnmWDpIS8GBhDR8Dktj/vChQk5OgvnwYcY3NdaJ82ekb3z4wwa3FggwQOMfIKRhFIyCUTAKRgF+AAC0E0wR3jEL/AAAAABJRU5ErkJggg==","orcid":"","institution":"University of Naples Federico II","correspondingAuthor":true,"prefix":"","firstName":"Mario","middleName":"","lastName":"Tortora","suffix":""},{"id":633564722,"identity":"858cb429-beab-474a-9796-8b3e015beee8","order_by":2,"name":"Valentina Toto","email":"","orcid":"","institution":"University of Milan","correspondingAuthor":false,"prefix":"","firstName":"Valentina","middleName":"","lastName":"Toto","suffix":""},{"id":633564723,"identity":"1db75fff-991d-43dd-8860-24004a491b17","order_by":3,"name":"Mariano Lanna","email":"","orcid":"","institution":"Ospedale dei Bambini Vittore Buzzi","correspondingAuthor":false,"prefix":"","firstName":"Mariano","middleName":"","lastName":"Lanna","suffix":""},{"id":633564724,"identity":"7e550956-d418-4890-988b-3652c519114b","order_by":4,"name":"Chiara Doneda","email":"","orcid":"","institution":"Ospedale dei Bambini Vittore Buzzi","correspondingAuthor":false,"prefix":"","firstName":"Chiara","middleName":"","lastName":"Doneda","suffix":""},{"id":633564725,"identity":"4f134d4a-6467-4566-94c8-a78a51e66fb5","order_by":5,"name":"Filippo Arrigoni","email":"","orcid":"","institution":"Ospedale dei Bambini Vittore Buzzi","correspondingAuthor":false,"prefix":"","firstName":"Filippo","middleName":"","lastName":"Arrigoni","suffix":""},{"id":633564726,"identity":"dd14865b-c5ca-4cbb-81ed-31dc2e474837","order_by":6,"name":"Fabio Tortora","email":"","orcid":"","institution":"University of Naples Federico II","correspondingAuthor":false,"prefix":"","firstName":"Fabio","middleName":"","lastName":"Tortora","suffix":""},{"id":633564727,"identity":"3ee0a36a-3801-4db8-8c3c-a602b19f7e1e","order_by":7,"name":"Cecilia Parazzini","email":"","orcid":"","institution":"Ospedale dei Bambini Vittore Buzzi","correspondingAuthor":false,"prefix":"","firstName":"Cecilia","middleName":"","lastName":"Parazzini","suffix":""},{"id":633564728,"identity":"66eeef30-7af5-400c-b2db-66351b13da21","order_by":8,"name":"Andrea Righini","email":"","orcid":"","institution":"Ospedale dei Bambini Vittore Buzzi","correspondingAuthor":false,"prefix":"","firstName":"Andrea","middleName":"","lastName":"Righini","suffix":""}],"badges":[],"createdAt":"2026-04-23 11:54:42","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9506392/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9506392/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108978805,"identity":"2e834e58-8e56-43fc-86fc-da2f4004c3ee","added_by":"auto","created_at":"2026-05-11 11:48:46","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":24122490,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eNormal appearance of cerebral surface and cerebral laminar pattern by multimodal post-mortem imaging (C) and histopathological correlation (A, B) in a 21 GA normal ex fetu.\u003c/em\u003e From the outside, GFAP immunohistochemical staining depicts the primitive leptomeningeal layer with a pial vessel (arrowhead) within it; pial cells are important in the PBM (arrows) stabilization.\u003cem\u003e \u003c/em\u003eThe radial glial end feet (colored in brown just below the PBM) are tightly anchored to PBM through specific receptors; this complex guarantees the physiological migration of neurons precursor and their proper laminar positioning. In B NeuN immunohistochemical stain reveals the normal laminar organization of neurons within the cortical plate: NeuN stains nuclei of neurons only in the inner two-thirds of the plate, corresponding to future layers 4–6 (double stars). In C, high resolution pmMRI coronal image shows the transient cerebral laminar pattern from the outside: leptomeningeal space (black dot), cortical plate (white dot), the subplate (white square bracket) with talamo-cortical fibers representation within its upper part (arrow), the intermediate zone (double black dot), the periventricular zone (black square bracket) and the germinal zone (the white line).\u003c/p\u003e","description":"","filename":"Fig.1.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-9506392/v1/edfbb6d5c3d4e20717903314.png"},{"id":108978797,"identity":"9fcfa5fb-34ea-4fc3-b6bb-76252426c31c","added_by":"auto","created_at":"2026-05-11 11:48:35","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":12726273,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eMultimodal imaging and histopathological correlation in a recipient twin with twin-to-twin transfusion syndrome (TTTS) treated with fetoscopic laser therapy, complicated by middle cerebral artery territory infarction and early PMG.\u003c/em\u003e Fetal MRI T2-weighted coronal image (a) demonstrates volume loss of the affected hemisphere, with associated cortical plate irregularity. Post-mortem MRI T2-weighted axial image (b) better delineates the cortical abnormality and the irregular thickening of the leptomeningeal layer (black dot) appearing as an irregular band extending beyond the expected cortical boundary (white dot). The subplate is also reduced. Histopathological GFAP analysis (c) confirms imaging findings, showing the typical cortical festooning pattern, consistent with polymicrogyria; the higher magnification images (d,e) demonstrate the results of the cerebral surface vascular damage (see in f the normal appearance of the cerebral surface) showing microstructural alterations of PBM (empty oval) and foci of laminar necrosis (black oval), leptomeningeal thickening associated with ectopic neurons, and the presence of ectopic glial cells (colored in brown), associated with macrophages infiltrate and meningeal vessels proliferation. Reactive gliosis in the marginal zone (colored in brown) and subplate (not shown) was also evident.\u003c/p\u003e","description":"","filename":"Fig.2.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-9506392/v1/83901a4596505b00b5c8834f.png"},{"id":108978855,"identity":"78fb123f-5b27-4a84-b8fe-650ab0972eb1","added_by":"auto","created_at":"2026-05-11 11:49:17","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":25235529,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eMultimodal imaging and histopathological correlation in congenital cytomegalovirus (CMV) infection with asymmetric, stage-dependent PMG.\u003c/em\u003e Fetal MRI T2-weighted axial images (a) show mild hemispheric asymmetry with relative parenchymal thinning and ventricular enlargement on the more affected side, as a sign of parenchymal damage; cortical plate irregularity is only faintly appreciable. ADC maps (b) demonstrate marked cortical plate diffusion restriction in that hemisphere, with subtler contralateral involvement, suggesting temporally heterogeneous injury.\u003c/p\u003e","description":"","filename":"Fig.3.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-9506392/v1/27a17480bf0f1d55ac0de686.png"},{"id":108978866,"identity":"11b36d06-dbb0-4c17-abf2-ab905d5f3361","added_by":"auto","created_at":"2026-05-11 11:49:32","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":10248073,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eMultimodal imaging and histopathological correlation in unilateral PMG associated with hemimegalencephaly in PIK3CA mutation.\u003c/em\u003e Fetal MRI coronal and axial T2-weighted images (a–b) demonstrate marked hemispheric asymmetry, with enlargement of the affected hemisphere with subtle irregularity of the cortical plate suggestive of PMG. PmMRI T2-weighted coronal and axial images (c-d) provide improved delineation of cortical abnormalities, demonstrating polymicrogyric features with expansion and blurring of the whole layers. The typical outer subplate band corresponding to thalamo-cortical fibers is no longer appreciable. Note the overall parenchymal lower signal respect the contralateral, due to higher cellularity. Histopathological analysis (NeuN staining) (e,f) demonstrates the characteristic cortical “festooning” pattern. At high magnification image (f) an increased neuronal density is observed in the superficial cortical layers respect to the normal one, consisting in abnormal cortical lamination. The pial basement membrane and superficial leptomeningeal layer are preserved.\u003c/p\u003e","description":"","filename":"Fig.4.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-9506392/v1/9cba409cb92094de50f6f7aa.png"},{"id":108978807,"identity":"221c1c52-3f30-4e7a-bc5e-a246b506f0c1","added_by":"auto","created_at":"2026-05-11 11:48:46","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":19494864,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eMultimodal imaging and histopathological correlation in cobblestone-PMG-like cortical dysplasia” associated with GPR56 mutation.\u003c/em\u003e Fetal MRI sagittal and axial T2-weighted images (a–b) demonstrate irregularities along the cortical rim with focal bump appearance (arrow in b) in frontal lobes associated to small subependymal heterotopic nodules (arrow in a). Also note on sagittal section (a) cerebellar vermis hypoplasia. Post-mortem MRI sagittal and axial T2-weighted images (c–d) better delineate the cortical abnormality, showing diffuse thickening and irregularity of the cortical plate similar to PMG cortex in the parietal regions, with evidence of an outer layer beyond the T2 hypointense cortical rim , and focal areas where the cortical profile appears disrupted, corresponding to the “mushroom-like” projections (arrows in d), giving rise to cobblestone-like appearance of the cortical surface at the vertex; cerebellar vermian hypoplasia is also shown in c. Histopathological analysis (e–h) confirms these findings, demonstrating a complex cortical malformation pattern where PMG aspects and cobblestone-like features were merged, as shown in Gfap immunohistochemistry coronal view 2,5 X (e). High magnification immunohistochemistry CD34 20X (e1) shows the PMG cortex with arrangement of the cortical plate in one or more festooning bands; see the entrapped vessel within fused sulcus (arrow); on the contrary high magnification immunohistochemistry CD34 20X (e2) demonstrates the cobblestone cortex with complete disorganization of the cortical plate; see the entrapment of meningeal vessel within the subplate (arrowhead). Gfap 20X stain (g) demonstrates loss of the normal boundary between the cortical plate and the superficial leptomeningeal layer, with neuronal overmigration (arrowhead) due to disruption of the PBM (arrow).\u003c/p\u003e","description":"","filename":"Fig.5.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-9506392/v1/ae2a59602298f49f48342938.png"},{"id":108981146,"identity":"04427992-8afd-4000-9821-f4516e0ce093","added_by":"auto","created_at":"2026-05-11 12:14:31","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":85424082,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9506392/v1/1d075710-de8d-4655-bd44-85018d104878.pdf"},{"id":108978798,"identity":"184bfbc2-42ab-4409-acde-cc0454a2188e","added_by":"auto","created_at":"2026-05-11 11:48:36","extension":"png","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":8863953,"visible":true,"origin":"","legend":"","description":"","filename":"GraphicalAbstract.tiff.png","url":"https://assets-eu.researchsquare.com/files/rs-9506392/v1/69e04a56faeba8c2e6c911ea.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Laminar Pattern Disruption in fetal incipient polymicrogyria: Insights from Post-Mortem MR Imaging and Neuropathological Correlation","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePolymicrogyria (PMG) represents a spectrum of cortical malformations characterized by excessive small gyri and abnormal cortical lamination [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIt is increasingly recognized as a final common pathway of multiple developmental insults rather than a single disease entity [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe pathogenesis of PMG is heterogeneous and includes genetic mutations, intrauterine infections (particularly cytomegalovirus), vascular insults and metabolic disturbances [\u003cspan additionalcitationids=\"CR6 CR7\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThese mechanisms interfere with critical stages of corticogenesis, including neuronal proliferation, migration, and cortical organization [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eNormal cortical development between 20- and 24-weeks of gestation is characterized by a well-defined transient laminar structure, reflecting coordinated neuronal migration and radial glial scaffolding [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Precocious disruption of these processes can lead to abnormal cortical folding and lamination, as seen in PMG [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eRecent advances in fetal MRI (fMRI) and especially high-resolution post-mortem MRI (pmMRI) have significantly improved the ability to detect early cortical abnormalities [\u003cspan additionalcitationids=\"CR15 CR16\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. pmMRI, with its superior spatial resolution, allows detailed visualization of transient fetal lamination (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) and subtle cortical abnormalities that are often not appreciable in vivo [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eNeuropathological studies have highlighted the importance of the integrity of the cortical surface and in particular the role of the pial basement membrane (PBM) and radial glial anchorage in normal corticogenesis [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Disruption of this interface has been identified as a key mechanism in several forms of PMG, particularly those associated with overmigration disorders [\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn this study, we aim to correlate early imaging findings with histopathological features in a series of fetuses with incipient PMG, to identify imaging biomarkers that reflect distinct etiopathogenic mechanisms.\u003c/p\u003e"},{"header":"Material and methods","content":"\u003cp\u003e\u003cem\u003ePatients\u0026rsquo; data\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eWe retrospectively analyzed four fetuses at 21 weeks\u0026rsquo; GA referred for suspected cortical malformation based on fMRI. Following multidisciplinary counseling, termination of pregnancy (TOP) was performed in all cases. Parental consent was obtained for post-mortem imaging and neuropathological examination.\u003c/p\u003e\n\u003cp\u003eThe fetuses were stored at 4\u0026ndash;5 \u0026deg;C and underwent pmMRI within 24 hours after delivery, scanned fresh. Subsequently, complete neuropathological examination was performed.\u003c/p\u003e\n\u003cp\u003eCases were selected to represent distinct etiopathogenic categories of PMG, including ischemic, infectious, and genetic forms, as well as a spectrum of radiological and anatomical presentations.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eMRI methods\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003ePrenatal MRI examinations were performed on a 1.5-T system (Ingenia, Philips Medical Systems, Best, the Netherlands). The imaging protocol included multiplanar T2-weighted single-shot fast spin-echo sequences with a slice thickness of 3 mm and an in-plane resolution of approximately 1 mm\u0026sup2;, complemented by balanced steady-state free precession sequences, T1-weighted fast spin-echo sequences, and axial diffusion-weighted imaging (DWI).\u003c/p\u003e\n\u003cp\u003ePost-mortem MRI was performed on the same 1.5-T system using either a dedicated neonatal head coil or the smallest available coil adapted to fetal size. In selected cases, saline bags were positioned within the coil to improve signal homogeneity. The imaging protocol included high-resolution T2-weighted fast spin-echo sequences with a slice thickness of 2 mm and an in-plane resolution of approximately 0.3 mm\u0026sup2;, as well as three-dimensional turbo spin-echo T1-weighted sequences and axial DWI. This approach enabled detailed visualization of transient fetal brain lamination and subtle cortical abnormalities.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNeuropathology\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eBrain extraction and fixation were performed according to Gilbert-Barness protocol [23]. After fixation, standardized sampling included three coronal sections at predefined levels from the frontal to occipital lobes in both hemispheres and three horizontal sections extending from the mesencephalon to the medulla oblongata. Tissue samples were embedded in paraffin and stained with hematoxylin-eosin for routine histological assessment. Representative sections were selected for immunohistochemical analysis using antibodies against neuronal nuclear antigen (NeuN) (NeuN- clone A60-Dako; 1:100), glial fibrillary acidic protein (GFAP) (GFAP- ready to use polyclonal-Dako), CD34 (QBEND10 clone-Dako; 1:100) and neuron-specific enolase (NSE) (BBS-NC-VI clone-Dako; 1:100). Immunohistochemistry was performed using DAKO-Omnis following the standard automatic protocol.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eImage and histopathological analysis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003ePmMRI datasets were reviewed and systematically correlated with histopathological findings. Attention was paid to cortical plate thickness and morphology, presence of extracortical tissue or neurons overmigration, appearance of the pial surface and PBM integrity, alteration of the other parenchimal layers, and associated supratentorial and infratentorial anomalies. Comparative analysis between prenatal MRI, post-mortem MRI, and histology was performed to identify imaging correlates of specific etiopathogenic mechanisms. In \u003cem\u003eFig. 1\u003c/em\u003e is reported an exemplificative case of normal appearance of cerebral surface and cerebral laminar pattern by multimodal post-mortem imaging and histopathological correlation in a 21 GA normal ex fetu.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eEthical statement\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAll procedures performed in the studies involving human participants were in accordance with the 1964 Helsinki Declaration.The cases were recruited as clinical cases with ethical approval for retrospective review of clinical notes and MR images by the \u0026ldquo;Milano Area 1\u0026rdquo; Ethics Committee (n. 27757/2022 protocol approval code). Informed consent was obtained from all individual participants included in the study.\u003c/p\u003e\n\u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cem\u003eOverview\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAll cases demonstrated abnormalities of cortical development that were more clearly appreciable on post-mortem MRI than on prenatal imaging. Distinct patterns emerged according to the underlying etiology, particularly regarding the symmetry of cortical involvement, the appearance of cerebral surface, the integrity of the PBM, the presence of inflammatory changes, degree and pattern of laminar disruption, and associated structural abnormalities.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eIschemic PMG secondary to Twin-to-Twin Transfusion Syndrome (TTTS); Fig. 2.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThis case involved a PMG associated with infarction in the territory of the middle cerebral artery in an ex-co-twin, after death of the donor as a complication of twin-to-twin transfusion syndrome (TTTS) treated with laser therapy. In-vivo imaging showed a clear reduction in the volume of one hemisphere, consistent with tissue loss. Coronal sections highlighted an associated irregularity of the cortical plate in perisylvian fronto-parietal areas with a \u0026ldquo;wartlike\u0026rdquo; appearance, as described in [24]. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePmMRI further elucidated this cortical anomaly: the cortical plate showed a wavy appearance and irregular thickening that appears to extend beyond its expected boundary. The subplate was also markedly reduced. Immuno-Histological sections confirmed what was observed on pm-MRI. GFAP staining demonstrated the classic festooned appearance of the cerebral surface seen in PMG. In the higher-magnification images, foci of laminar necrosis and a micro-regional alteration of the PBM were evident, along with leptomeningeal thickening related to the presence of extrapial ectopic neurons and glial cells associated with macrophages infiltrate and meningeal vessels proliferation. Reactive gliosis in the marginal zone and subplate was also evident.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePMG due to Congenital Cytomegalovirus (CMV) Infection; Fig. 3.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIn the second scenario, PMG developed following intrauterine cytomegalovirus (CMV) infection, a known cause of cortical malformation development due to its specific tropism for radial glial progenitor cells. In-vivo imaging was instrumental in identifying early signs of this disruption; on axial fetal scans, there was a mild asymmetry in parenchymal thickness with enlargement of the lateral ventricle in the smaller hemisphere. On that side a subtle irregularity along the cortical plate was evident raising suspicion of a cortical developmental anomaly. Even DWI showed an asymmetric restriction of water diffusion along the cortical plate between the two hemispheres, more prominent/severe in the smaller hemisphere. This suggested an asynchronous involvement of the two hemispheres, with a manifest appearance in one hemisphere and evidence of a still ongoing infective process on the other side. PmMRI clarified the pre-natal cerebral findings. In the smaller hemisphere there was an already established PMG pattern, with a thickened and irregular cortical plate characterized by excessive abnormal small cerebral gyri, indistinct subplate, reduction of intermediate zone and disruption of the germinal zone. A T2 markedly hypointense rim along the cortical ribbon was also evident, possibly reflecting laminar necrosis and calcium deposits, probably corresponding to the areas of prominent diffusion restriction on in-vivo imaging. On the opposite, the other hemisphere (on the radiological right in Fig.2) demonstrated an earlier stage of the parenchymal infectious involvement with overall increasing of T2 weighted signal of cerebral layers due to edema; in particular the cortical plate was thickened with evidence of an outer extracortical layer, and inwards it appeared poorly distinguishable from the subplate, with undulating appearance of thalami-cortical fibers, the thin linear layer located in the upper portion of the subplate just below the lower portion of the cortical plate. Histopathology confirmed these MRI features. Immunohistochemical stains revealed a diffuse disorganization of the laminar pattern on both sides, with festooning appearance of the cortical plate at multiple sites of the left hemisphere consisting with polimicrogyria. NeuN stains showed bilateral cells rarefaction at the level of the periventricular germinal matrix as well as in the cortical plate and subplate, more evident in the left hemisphere. GFAP staining corroborated the NeuN findings, also demonstrating the profound derangement of the glial scaffold in the intermediate zone of both sides with intense reactive gliosis in the subplate and marginal zone of the left hemisphere. This glial response was consistent with chronic neuroinflammatory activity. Alike, leptomeningeal thickening was observed due to neovascularization and macrophages inflammatory infiltration at CD3 stains. Worthy of note, the MBP was preserved. \u0026nbsp; CD8 and CD3 staining respectively identified extensive lympho-macrophagic infiltration within the cortical plate and subplate as well as in the periventricular zone, more evident on the left side, confirming CMV\u0026rsquo;s tropism for stem cells and radial glial progenitors in the subventricular zone (SVZ). The microscopic differences between the two hemispheres mirror the asynchronous bilateral injury seen on imaging and illustrates how the virus not only interferes with cortical lamination but also induces a neuroinflammatory cascade that shapes the evolving morphology of the developing brain. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePost-mortem MRI T2-weighted coronal (c) and axial images (d) depict an established cortical PMG pattern in the smaller hemisphere (on the left), with cortical plate thickening, blurring and thinning of the intermediate zone and subplate, and involvement of germinal layers. The cortical plate appears marked hypointense, probablycorresponding to the stronger cortical diffusion restriction on that side seen in b, probably due to calcifications and laminar necrosis. The contralateral hemisphere represents an earlier stage, characterized by irregular cortical plate thickening and indistinguishable from the subplate, overall parenchymal swelling and hyperintensity, due to edema. At magnification image (e), note the undulation of the upper subplate layer corresponding to thalamo-cortical fibers, suggesting early cortical folding disturbance. At histopathology, NeuN staining images (f-h) confirm overt cortical \u0026ldquo;festooning\u0026rdquo; in the left hemisphere and cortical plate thickening and irregularity on the right side; in particular, high-magnification views (g-h) highlight the bilateral, diffuse cortical disorganization, derangement and cells rarefaction involving the wall layers, including those periventricular. These findings are more evident on the left hemisphere, consistent with stage-dependent CMV-related cortical injury. Left hemisphere GFAP high magnification stains (i,l) demonstrate multiple foci of gliosis (colored in brown, arrows) within the subplate and the marginal zone. On the higher magnification image (l) the PBM appears intact and leptomeningeal thickening is evident due to neovascularization phenomena and macrophages infiltrations, as seen at high magnification image CD3 stain (m). CD8 (n) and CD3 (o) staining respectively identified extensive lympho-macrophagic infiltration within the cortical plate and subplate as well as in the periventricular zone.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePMG with Hemimegaloencephaly due to PIK3CA Mutation; Fig. 4.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe third fetus showed unilateral PMG associated with hemimegalencephaly, genetically related to the PIK3CA gene mutation. This condition represents a classic example of cortical malformation driven by overgrowth syndromes. The fetal MRI clearly demonstrated marked hemispheric asymmetry, with the affected hemisphere appearing enlarged and displaying irregularity of the cortical plate. Even the laminar pattern was asymmetric either in layering, with intermediate zone and subplate expansion, and in signal, with an overall reduced T2 signal, suggesting the presence of higher cellularity within every layers. Post-mortem MRI provided further detail, benefiting from higher spatial resolution. The cortical surface was slightly thickened with a polymicrogyric appearance; the intermediate zone and even more the subplate were abnormally thick with respect to the other hemisphere and their boundaries appeared blurred. Importantly, the usual demarcation of the thalamocortical fibers within the outer subplate was no longer visible, indicating disruption of normal cortical-subcortical connectivity. The whole layers T2 signal was confirmed \u0026nbsp;to be reduced, for the reasons mentioned above. Histological analysis confirmed the imaging findings. Immunohistochemical staining for NeuN revealed an increased number of mature neurons in the superficial cortical layers, consistent with an aberrant cortical lamination pattern with inversion of the normal inside-out cortical proliferation with eventual premature folding. Despite these profound alterations in cortical architecture, both the PBM and the leptomeninges appeared intact, excluding a disruption of pial structures as a contributing factor. GFAP staining was normal, suggesting an absence of significant reactive gliosis. The hallmark features here\u0026mdash;festooning of the cortical plate, expansion of the intermediate and subplate zone, loss of subplate architecture, and inverted neuronal cortical layering\u0026mdash;point toward a pathogenesis driven by hyperactivation of the PI3K-AKT signaling pathway.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eGPR56-Related PMG with Cobblestone-Like Features; Fig. 5.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe fourth case involved a fetus with bilateral frontoparietal PMG caused by a mutation in the GPR56 gene, encoding a receptor complex expressed on the end feet of radial glial cells that mediate anchorage to the PBM. \u0026nbsp;Fetal MRI showed some irregularities along the cortical rim with focal bump appearance in frontal lobes associated to probable small subependymal heterotopic nodules. On sagittal sections, cerebellar hypoplasia was also noted. These findings suggested a complex early structural alteration involving both supratentorial and sub tentorial structures. Post-mortem MRI further clarified the malformation pattern. The cortical plate was markedly irregular and thick, with evidence of an outer layer beyond the T2 hypointense cortical rim associated to focal areas where this contour appeared interrupted with distinct cortical protrusion, giving rise to cobblestone-like appearance of the cortical surface. This pattern was particularly striking at the frontal vertex, while in the parietal regions a pattern like the PMG one was appreciable. An abnormal subplate and intermediate zone representation (reduced in thickness and blurred) was also evident, as markers of complex anomaly of the fetal cerebrum development. Histological examination confirmed these observations, demonstrating a complex cortical malformation pattern where PMG aspects and cobblestone-like features were merged. Histopathologically, cobblestone cortex anomaly typically consists in complete disorganization of the cortical plate with lack of normal laminar stratification, confirmed by a randomly distributed NeuN reactivity along the whole thickness of the cortical plate. In addition, GFAP staining demonstrated the discontinuity of the PBM at multiple sites, with cortical plate indistinguishable from the leptomeningeal space, associated to extrapial neuronal heterotopy and focal entrapment of meningeal vessels within the subplate was also evident at CD34 staining; a complete glial scaffold derangement was also present. On the contrary hallmark features of PMG consisted in cortical festooning bands organization of neurons and the presence of the entrapment of large vessels within fused sulci at CD34 staining. GFAP staining also demonstrated the presence of sparse glial cells in the subpial zone, extending through the superficial cortex. These findings aligned with the imaging features.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eUnlike typical PMG, GPR56-related malformations exhibit a mixed pattern of PMG and cobblestone dysplasia, cerebellar involvement, and an absence of clear cortical lamination, where the breakdown of the glia-pial anchorage plays a pivotal role.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn our series, we illustrated the morphological appearance of incipient PMG related to different pathogenetic pathways, each producing a characteristic morphological and histopathological profile, by using the correlation between high-resolution post-mortem imaging and immunohistopathology.\u003c/p\u003e\n\u003cp\u003eWith the development of MRI techniques, the image quality of in vivo fetal MRI has greatly improved; however, its diagnostic ability to demonstrate early anomalies of cortical development remains limited by sequence characteristics and magnetic field strength, such that it cannot clearly depict subtle changes in parenchymal stratification [25]. In our cases, fetal MRI only demonstrated irregularity of the cortical plate, eventually associated with volumetric reduction of the involved cerebral parenchyma. On the contrary, post-mortem MRI, also due to its higher in-plane resolution (approximately four times higher than fetal MRI), can clearly depict subtle changes in cerebral lamination suggestive of early disruption of cortical developmental processes, revealing precise correlations with findings observed in histological sections [26]. Similar results have been reported by Kang et al., comparing 1.5 T and 3 T modalities in terms of tissue contrast, diagnostic error, and diagnostic accuracy in post-mortem brain evaluation [14].\u003c/p\u003e\n\u003cp\u003eTransient lamination of the fetal cerebrum is normally observed between 20 and 24 weeks of gestation and represents a marker of normal cerebral development, reflecting changes in cellularity, fiber organization, neuronal migration, and cortical organization processes [15-16]. The development of a normal cortical sulcal and gyral pattern depends on the successful generation of neuroblasts in the germinal matrix, their migration to the cortical surface along the radial glial scaffold, and their proper organization within the developing cerebral cortex. Proper neuronal migration and laminar positioning are supported by the anchorage of radial glial processes to the pial basement membrane through receptors located on their end feet. Primitive leptomeninges and pial cells also stabilize the pial basement membrane, playing a crucial role in maintaining the integrity of the cortical surface and overall cortical organization. The importance of brain surface integrity for normal corticogenesis has been demonstrated in both experimental and human studies; in large series of fetal PMG at early gestational age, pial defects and neuronal over migration have been observed in a high proportion of cases, regardless of genetic or acquired origin [18,19].\u003c/p\u003e\n\u003cp\u003eAll these steps are tightly coordinated in space and time. Therefore, a pathological process interfering with one of these mechanisms can secondarily disrupt the others. For example, abnormalities in neuronal migration are commonly associated with altered sulcation and gyration patterns, and vice versa. Based on this, disruption of the expected appearance and signal intensity within cerebral lamination on post-mortem MRI can be considered an early indicator of abnormal cortical development, as confirmed in our series. Moreover, in our cases, post-mortem MRI, corroborated by histopathology, demonstrated specific features useful for distinguishing different pathogenic pathways.\u003c/p\u003e\n\u003cp\u003eIn ischemic PMG, the prototypical pattern is characterized by marked asymmetry in cortical involvement, depending on the vascular territory, and by a temporal relationship with the ischemic event. Imaging and histopathological findings included the presence of an extracortical layer due to thickening of the meningeal layers associated with extrapial ectopic neurons and glial cells, macrophage infiltration, and vascular proliferation related to focal disruption of the pial basement membrane. Signs of cortical laminar necrosis were also evident. The laminar pattern was locally altered, with marked reduction of the subplate and associated gliosis. These findings confirm the deleterious impact of acute, regionally selective vascular insults on corticogenesis, as also demonstrated in previous neuropathological studies [21, 27]. Importantly, in this context, the timing of the insult was known, as imaging was performed approximately two weeks after laser therapy, allowing us to confidently identify this pattern as incipient PMG secondary to a vascular event [28].\u003c/p\u003e\n\u003cp\u003eIn PMG caused by congenital cytomegalovirus infection, a different spectrum of cerebral abnormalities was observed, as this viral insult disrupts both neuronal and glial progenitors, resulting in combined periventricular and cortical injury with a typically bilateral distribution. In our case, imaging demonstrated bilateral involvement with an asynchronous pattern typical of early infection, with one hemisphere showing established PMG with cortical calcifications and parenchymal volume loss, and the contralateral hemisphere showing features of an ongoing infective process. The latter represents a prototype of early infection-related cortical malformation, characterized by irregular leptomeningeal and cortical thickening, indistinct cortical–subplate boundaries, and germinal zone injury, with overall parenchymal T2 hyperintensity and swelling reflecting edema, inflammation, and active tissue disorganization. A key observation was the undulating appearance of thalamocortical fibers within the upper subplate, like the cortical plate was crumpling up on the upper part of the subplate, reflecting disruption of the interface between the cortical plate and subplate, and highlighting the crucial role of the subplate in cortical folding and organization [29]. Neuropathological analysis confirmed these findings and demonstrated preservation of the pial basement membrane, in contrast to ischemic forms. These features underline the tropism of cytomegalovirus for progenitor cells in the germinal zone and its disruptive effect on cortical development through inflammation, cell death, and laminar disorganization [30-33].\u003c/p\u003e\n\u003cp\u003eIn contrast, genetic forms of PMG lack of the constellation of features typically observed in acquired (clastic) forms and instead show distinct patterns depending on the underlying mutation. However, a single PMG phenotype may arise from different genetic etiologies, and conversely, the same genetic mutation may produce variable imaging patterns [34].\u003c/p\u003e\n\u003cp\u003eIn the case of PMG associated with hemimegalencephaly due to PIK3CA mutation, post-mortem MRI demonstrated an asymmetric laminar pattern characterized by expansion of the intermediate zone and subplate, blurring of their boundaries, and globally reduced T2 signal intensity, suggesting increased cellularity across all layers and reflecting extensive structural disorganization. The cortical plate was mildly thickened with a wavy appearance, without evidence of an extracortical layer. Histologically, the PBM and leptomeninges were preserved, and no inflammatory changes or gliosis were observed. Conversely, an increased number of mature neurons in superficial cortical layers was identified, consistent with an inverted laminar organization. This abnormal distribution reflects a fundamental disturbance in neuronal migration and positioning, with consequent alteration of radial connectivity and tangential cortical growth processes that normally drive gyration. These findings are consistent with hyperproliferation, and impaired apoptosis of neuronal progenitors related to PI3K-AKT pathway activation [35-36].\u003c/p\u003e\n\u003cp\u003eThe second genetic case involved bilateral frontal-parietal PMG due to GPR56 mutation. This case has been previously reported by us as general features, but as a single isolated entity and not compared and discussed with other forms of PMG as in the present context [37]. This condition provides further insights into the developmental mechanisms underlying PMG, as it results from failure of glial–pial anchorage due to defective interaction between radial glial endfeet and the PBM. This leads to disruption of the glial scaffold, focal breaks in the PBM, and secondary neuronal overmigration during critical stages of brain development, ultimately resulting in abnormal cortical organization and folding. The characteristic imaging and histopathological findings in our case included the coexistence of polymicrogyria in parietal regions and cobblestone-like cortex in frontal regions, with extracortical protrusions related to neuronal and glial overmigration through defects in the PBM. Abnormal representation of the subplate and intermediate zone was also observed, reflecting disruption of the glial scaffold necessary for normal laminar organization. This process is now considered within the spectrum of cobblestone-like cortical malformations due to shared pathogenetic mechanisms with dystroglycanopathies [38]\u003c/p\u003e\n\u003cp\u003eCollectively, these cases illustrate the morphological continuum of PMG as shaped by different developmental insults. Rather than representing a single disease entity, PMG should be considered a convergent endpoint of multiple pathogenic processes affecting cortical development, each characterized by distinct molecular, structural, and temporal features. A unifying concept emerging from both imaging and histopathology is the central role of the pial surface and its integrity in orchestrating normal corticogenesis.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003ePMG is not a single entity but a spectrum of cortical malformations reflecting diverse developmental disturbances. The integration of pmMRI and neuropathology allows early identification of etiological patterns, improving diagnostic accuracy and counseling for possible further pregnancies.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eG.I., M.T. and A.R. contributed to study conception and design.G.I, V.T. and M.L. performed data collection.C.D, F.A., F.T. and C.P. performed image analysis.G.I. and M.T. drafted the manuscript.All authors revised the manuscript critically and approved the final version.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBarkovich AJ, Guerrini R, Kuzniecky RI, Jackson GD, Dobyns WB (2012) A developmental and genetic classification for malformations of cortical development: update 2012. 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Am J Med Genet C Semin Med Genet 166C:156\u0026ndash;172\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMirzaa GM, Campbell CD, Solovieff N et al (2016) Association of MTOR mutations with developmental brain disorders, including megalencephaly, focal cortical dysplasia, and pigmentary mosaicism. JAMA Neurol 73:836\u0026ndash;845\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKeppler-Noreuil KM, Rios JJ, Parker VE et al (2015) PIK3CA-related overgrowth spectrum (PROS): diagnostic and testing eligibility criteria, differential diagnosis, and evaluation. Am J Med Genet A 167A:287\u0026ndash;295\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIzzo G, Toto V, Faiola S et al (2023) Cobblestone-like brain malformation with a new bi-allelic ADGRG1 (GPR-56) mutation: fetal imaging\u0026ndash;pathology correlation. J Neuroimaging 33:527\u0026ndash;533\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChiang NY, Hsiao CC, Huang YS et al (2011) Disease-associated GPR56 mutations cause bilateral frontoparietal polymicrogyria via multiple mechanisms. J Biol Chem 286:14215\u0026ndash;14225\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"pediatric-radiology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prad","sideBox":"Learn more about [Pediatric Radiology](http://link.springer.com/journal/247)","snPcode":"247","submissionUrl":"https://submission.nature.com/new-submission/247/3","title":"Pediatric Radiology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Polymicrogyria, fetal MRI, post-mortem MRI, cortical development, neuropathology","lastPublishedDoi":"10.21203/rs.3.rs-9506392/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9506392/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003ePolymicrogyria (PMG) is a heterogeneous cortical malformation resulting from disruption of multiple processes of cortical development, either genetically or clastic determined.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eTo characterize early imaging and histopathological features of incipient PMG in fetuses at early gestational age and correlate radiological patterns with underlying etiopathogenic mechanisms.\u003c/p\u003e\u003ch2\u003eMaterials and methods\u003c/h2\u003e \u003cp\u003eFour fetuses at 21 weeks\u0026rsquo; gestational age (GA) with suspected PMG on fetal MRI underwent post-mortem MRI (pmMRI) and detailed neuropathological examination, including immunohistochemistry (NeuN, GFAP, MBP, CD3, CD68). Imaging and histological findings were systematically compared.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eDistinct imaging\u0026ndash;histopathological patterns were identified according to etiology (ischemic, infectious, genetic). Key differentiating features included symmetry of involvement, cerebral surface appearance, integrity of the pial basement membrane, laminar pattern alterations and associated anomalies.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eCombined pmMRI and neuropathology enable early characterization of PMG and provide insights into its etiopathogenesis, improving differential diagnosis and genetic counseling.\u003c/p\u003e","manuscriptTitle":"Laminar Pattern Disruption in fetal incipient polymicrogyria: Insights from Post-Mortem MR Imaging and Neuropathological Correlation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-11 07:03:56","doi":"10.21203/rs.3.rs-9506392/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"15883979276964738071743751113105898453","date":"2026-05-19T06:17:45+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-06T05:35:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"285686342961077973830592134325422006403","date":"2026-05-03T09:06:41+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"83947250151884547554064781060313506198","date":"2026-04-28T16:57:20+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-28T04:24:21+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-27T11:40:13+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-27T11:39:15+00:00","index":"","fulltext":""},{"type":"submitted","content":"Pediatric Radiology","date":"2026-04-23T11:39:46+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"pediatric-radiology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prad","sideBox":"Learn more about [Pediatric Radiology](http://link.springer.com/journal/247)","snPcode":"247","submissionUrl":"https://submission.nature.com/new-submission/247/3","title":"Pediatric Radiology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"41516773-ebb1-4c6b-aee3-c6d9732ae1e4","owner":[],"postedDate":"May 11th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"15883979276964738071743751113105898453","date":"2026-05-19T06:17:45+00:00","index":25,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-06T05:35:39+00:00","index":23,"fulltext":""},{"type":"reviewerAgreed","content":"285686342961077973830592134325422006403","date":"2026-05-03T09:06:41+00:00","index":22,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-11T07:03:56+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-11 07:03:56","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9506392","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9506392","identity":"rs-9506392","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}