Resection of the tumor in the trigone of the lateral ventricle via the contralateral posterior interhemispheric transfalcine transprecuneus approach with multi-modern neurosurgery technology: a case report.

Choroid plexus papilloma (CPP) is a rare benign intracranial tumor origin that predominantly manifests in the lateral ventricle in children, accounting for 0.3%-0.6% of all primary intracranial tumors. It is extremely rare to have the CPP in the trigone of the lateral ventricle through the contralateral posterior interhemispheric transfalcine transprecuneus approach (PITTA). Herein, we report this rare case. A 7-year-old girl presented with headache. Magnetic resonance imaging of the brain showed periatrial lesions, and histopathological examination confirmed CPP (WHO grade I). The contralateral PITTA is a safe, effective, reasonable, and appropriate for some lesions in the trigone of the lateral ventricle. It provides a wider surgical angle (especially for the lateral extension) and reduces the risk of disturbance of the optic radiation compared with the conventional approaches. The use of multiple modern neurosurgical techniques, including interventional embolization, intraoperative navigation, microscope, and electrophysiological monitoring, make the procedure much easier and more accurate, and the neuroendoscope adds to the visualization of the microscope and can reduce surgical complications.

Cerebrospinal Fluid Parameters Predicting Contralateral Isolated Lateral Ventricle in Adult Tuberculous Meningitis with Hydrocephalus Post-Ventriculoperitoneal Shunt.

OBJECTIVE: Hydrocephalus, a major complication in tuberculous meningitis (TBM) patients, often necessitates treatment via ventriculoperitoneal shunt (VPS). However, post-VPS, some patients develop a complication called contralateral isolated lateral ventricle (CILV), leading to persistent hydrocephalus symptoms. This study aims to evaluate cerebrospinal fluid (CSF) parameters in predicting CILV occurrence post-VPS in adult TBM patients. METHODS: A retrospective analysis was conducted, focusing on the relationship between preoperative CSF parameters and the development of CILV in 40 adult TBM patients who underwent VPS. The study compared CSF parameters from lumbar puncture after admission with those from ventricular CSF post-external ventricular drainage tube insertion. RESULTS: CILV was observed in 6 of the 40 patients following VPS. Statistical analysis showed no significant difference between the CSF parameters obtained via lumbar and ventricular punctures. Notably, the mean CSF glucose level in patients with CILV was significantly lower (1.92 mmol/L) compared to the non-CILV group (3.03 mmol/L). Conversely, the median adenosine deaminase (ADA) level in the CILV group was higher (5.69 U/L) compared to the non-CILV group (3.18 U/L). The optimal cutoff values for CSF glucose and ADA levels were 1.90 mmol/L and 4.80 U/L, respectively, with a sensitivity of 66.67% and 83.33% and a specificity of 88.24% and 79.41%. CONCLUSIONS: The study identified elevated ADA levels and decreased glucose levels in CSF as potential risk factors for CILV development in adult TBM patients post-VPS. These findings suggest the necessity for more tailored surgical approaches, in patients with altered CSF parameters to mitigate the risk of CILV.

Alterations in Blood-Brain Barrier Integrity and Lateral Ventricle Differ in Rats Exposed to Space Radiation and Social Isolation.

The proposed Mars missions will expose astronauts to long durations of social isolation (SI) and space radiation (SR). These stressors have been shown to alter the brain's macrostructure and microenvironment, including the blood-brain barrier (BBB). Breakdown of the BBB is linked to impaired executive functions and physical deficits, including sensorimotor and neurocognitive impairments. However, the precise mechanisms mediating these effects remain unknown. Additionally, the synergistic effects of combined exposure to SI and SR on the structural integrity of the BBB and brain remain unknown. We assessed the BBB integrity and morphology in the brains of male rats exposed to ground-based analogs of SI and SR. The rats exposed to SR had enlarged lateral ventricles and increased BBB damage associated with a loss of astrocytes and an increased number of leaky vessels. Many deficits observed in SR-treated animals were attenuated by dual exposure to SI (DFS). SI alone did not show BBB damage but did show differences in astrocyte morphology compared to the Controls. Thus, determining how single and combined inflight stressors modulate CNS structural integrity is crucial to fully understand the multiple pathways that could impact astronaut performance and health, including the alterations to the CNS structures and cell viability observed in this study.

The Impact of Lateral Ventricular Opening in the Resection of Newly Diagnosed High-Grade Gliomas: A Single Center Experience.

Given the importance of maximizing resection for prognosis in patients with HGG and the potential risks associated with ventricle opening, this study aimed to assess the actual increase in post-surgical complications related to lateral ventricle opening and its influence on OS and PFS. A retrospective study was conducted on newly diagnosed HGG, dividing the patients into two groups according to whether the lateral ventricle was opened (69 patients) or not opened (311 patients). PFS, OS, subependymal dissemination, distant parenchymal recurrences, the development of hydrocephalus and CSF leak were considered outcome measures. A cohort of 380 patients (154 females (40.5%) and 226 males (59.5%)) was involved in the study (median age 61 years). The PFS averaged 10.9 months (±13.3 SD), and OS averaged 16.6 months (± 16.3 SD). Among complications, subependymal dissemination was registered in 15 cases (3.9%), multifocal and multicentric progression in 56 cases (14.7%), leptomeningeal dissemination in 12 (3.2%) and hydrocephalus in 8 (2.1%). These occurrences could not be clearly justified by ventricular opening. The act of opening the lateral ventricles itself does not carry an elevated risk of dissemination, hydrocephalus or cerebrospinal fluid (CSF) leak. Therefore, if necessary, it should be pursued to achieve radical removal of the disease.

Successful Surgical Treatment of a Giant Intraventricular Meningioma: A Case Report and Literature Review.

In our study, we document the case of a 48-year-old patient who presented at our clinic with various neurological disturbances. Magnetic Resonance Imaging revealed the presence of an intraventricular meningioma located in the body of the left lateral ventricle measuring 60 mm in diameter. This tumor was classified as a giant meningioma, accompanied by a significant amount of digitiform-type edema. A surgical procedure was conducted, resulting in a gross total resection of the tumor. Histopathological analysis identified the tumor as a fibrous meningioma. Postoperative assessments, as well as follow-ups conducted at 3 months and 1 year post-surgery, indicated considerable neurological improvement. The patient exhibited a remission of hemiparesis and gait disturbances along with a marginal improvement in the status of expressive aphasia. This case report underscores the significance of achieving total and safe resection of the tumor and includes an analysis of various cases from the literature, particularly focusing on those that describe minimally invasive surgical approaches and highlight the benefits of radiosurgery in the treatment of giant intraventricular meningiomas.

Intraventricular Tumors: Surgical Considerations in Lateral and Third Ventricular Tumors.

Management of lateral and third ventricular tumors has been a challenge for neurosurgeons. Advances in imaging and pathology have helped in a better understanding of the treatment options. Technical refinement of microsurgical technique and addition of endoscopy has enabled more radical excision of tumors, when indicated, and added more safety.A proper understanding of the pathology at various ages and treatment options is continuously evolving. Many pediatric tumors are amenable to conservative surgical methods with effective complementary treatments. However, radical surgery is required in many adults as the main treatment and for many benign tumors. Various intraventricular lesions encountered and their surgical management is reviewed here for their efficacy, safety, and outcome, encompassing changes in our practice over the last 20 years.

Anatomical surgical approach to lateral vetricle masses and histopathological findings of the brain.

BACKGROUND: The selection of surgical approach to the lateral ventricular masses includes difficulties due to their deep localizations, close proximity to the vascular and the eloquent brain structures. The most appropriate approach that should be chosen in surgical treatment of lateral ventricular masses is still controversial. In this study, the factors in the choice of surgical approach to the lateral ventricle masses and the results of them were investigated. MATERIALS AND METHODS: In this study, 80 patients who underwent surgery in our clinic due to the lateral ventricular masses were retrospectively analyzed between the years 2002-2013. All of the cases were evaluated in terms of clinical and neuroradiological results pre and postoperatively. In 24 cases the anterior interhemispheric transcallosal, in 4 cases the posterior interhemispheric transcallosal, in 30 cases the posterior interhemispheric precuneal, in 14 cases the transcortical and in 8 cases the combined surgical approaches were performed. RESULTS: Gender distribution of the cases were 45 male/35 female and the mean age of them was 31.7 years (7 month - 73 years). In 64 patients the gross total resection was performed, whereas in 16 patients subtotal resection was performed due to the infiltration of eloquent brain areas. In the histopathological examination; 52 neuroepithelial, 8 mixed neuroglial, 3 meningeal, 2 lympho-hematopoietic system, 1 pine blastoma, 1 germ cell, 5 metastatic and 8 other benign masses were observed. After surgery, additional neurological deficits developed in 9 patients. The mortality was observed in 6 patients postoperatively. The average follow-up time was 13 (1-83) months. CONCLUSIONS: The essential factors which affect the results of surgical treatment of lateral ventricular masses are; the size of the mass, histopathology, location, extension, and the relationship to the neurovascular structures. The goal of surgery is to provide the histopathological diagnosis, gross total resection, if it is possible, and to normalize the flow of cerebrospinal fluid by eliminating the mass effect of pressure.

Intraventricular Meningioma: A Case Report of a Common Tumor in an Uncommon Location.

Intraventricular meningiomas are uncommon neoplasms originating within the ventricular system of the brain, constituting a rare subset of central nervous system tumors. Their unique location poses diagnostic challenges, and understanding their clinical manifestations is imperative for effective management. We present the case of a 56-year-old female who sought medical attention due to persistent, severe headaches localized in the occipital region. Laboratory investigations demonstrated normal values for a complete blood count, electrolytes, and liver function tests. Magnetic resonance imaging revealed a well-defined mass in the left occipital horn of the lateral ventricle, indicative of an intraventricular meningioma. Surgical resection of the intraventricular meningioma resulted in the resolution of the patient's headaches. This case contributes valuable insights into the diagnostic challenges posed by intraventricular meningiomas.

FLAIR Hyperintensities in the Anterior Part of the Callosal Splenium in the Elderly Population: A Large Cohort Study.

RATIONALE AND OBJECTIVES: Although hyperintensity in the anterior portion of the callosal splenium on FLAIR (aCS-hyperintensity) is a common finding in elderly adults, no previous studies have examined the clinical significance. In this large elderly population study, we aimed to investigate the associations of aCS-hyperintensity with vascular risk factors, cognitive decline, and other MRI measurements. MATERIALS AND METHODS: This cross-sectional study included 2110 participants (median age, 69 years; 61.1% females) who underwent 3 T MRI. The participants were grouped as 215 with mild cognitive impairment (MCI) and 1895 cognitively normal older adults (NOAs). Two neuroradiologists evaluated aCS-hyperintensity by using a four-point scale (none, mild, moderate, and severe). Periventricular hyperintensities (PVHs) were also rated on a four-point scale according to the Fazekas scale. The total intracranial volume (ICV), total brain volume, choroid plexus volume (CPV), and lateral ventricle volume (LVV) were calculated. RESULTS: Logistic regression analysis showed diabetes was the main predictor of aCS-hyperintensity after adjusting for potential confounders (age, sex, hypertension, and hyperlipidemia) (p < 0.01), whereas PVH was associated with hypertension (p < 0.01). aCS-hyperintensity rated as "severe" was associated with a presence of MCI (p < 0.01). For the imaging factors, LVV was an independent predictor of aCS-hyperintensity when brain volume and PVH grade were added to the analysis (p < 0.01). CONCLUSION: Cerebral small vessel disease due to diabetes is a major contributor to the development of aCS-hyperintensity. Cerebrospinal fluid clearance failure may also relate to aCS-hyperintensity, which may offer new insights into the pathologic processes underlying MCI.

Enlarged choroid plexus in multiple sclerosis is associated with increased lesion load and atrophy in white matter but not gray matter atrophy.

BACKGROUND: Enlargement of the choroid plexus (CP) is reported to associate with inflammatory activity and contribute to brain atrophy in patients with multiple sclerosis (pwMS). However, a recent study in healthy volunteers (HVTs) has suggested that CP enlargement can be attributed to ventriculomegaly. OBJECTIVES: To clarify the pathological significance of the enlargement of CP in multiple sclerosis (MS). METHODS: A total of 102 pwMS (89 with relapsing-remitting MS and 13 with secondary progressive MS) and 41 HVTs were cross-sectionally evaluated using brain volumetry. The CP volume was compared between disease groups and investigated for the relationships with other brain regional volumes. RESULTS: CP volume was significantly larger in pwMS than in HVTs in the univariate analysis, but not in multivariable analysis. Meanwhile, the CP and lateral ventricle (LV) volumes were significantly correlated. CP enlargement was significantly associated with increased lesion load and cerebral white matter (WM) atrophy, even after adjusting for LV volume. In contrast, multivariable analyses revealed that LV enlargement, but not CP enlargement, was associated with total gray matter (GM) atrophy. CONCLUSION: CP enlargement was closely associated with LV enlargement. After adjusting for LV volume, CP enlargement in pwMS was associated with increased lesion load and WM atrophy but not GM atrophy.

Linking enlarged choroid plexus with plasma analyte and structural phenotypes in clinical high risk for psychosis: A multisite neuroimaging study.

BACKGROUND: Choroid plexus (ChP) enlargement exists in first-episode and chronic psychosis, but whether enlargement occurs before psychosis onset is unknown. This study investigated whether ChP volume is enlarged in individuals with clinical high-risk (CHR) for psychosis and whether these changes are related to clinical, neuroanatomical, and plasma analytes. METHODS: Clinical and neuroimaging data from the North American Prodrome Longitudinal Study 2 (NAPLS2) was used for analysis. 509 participants (169 controls, 340 CHR) were recruited. Conversion status was determined after 2-years of follow-up, with 36 psychosis converters. The lateral ventricle ChP was manually segmented from baseline scans. A subsample of 31 controls and 53 CHR had plasma analyte and neuroimaging data. RESULTS: Compared to controls, CHR (d = 0.23, p = 0.017) and non-converters (d = 0.22, p = 0.03) demonstrated higher ChP volumes, but not in converters. In CHR, greater ChP volume correlated with lower cortical (r = -0.22, p < 0.001), subcortical gray matter (r = -0.21, p < 0.001), and total white matter volume (r = -0.28,p < 0.001), as well as larger lateral ventricle volume (r = 0.63,p < 0.001). Greater ChP volume correlated with makers functionally associated with the lateral ventricle ChP in CHR [CCL1 (r = -0.30, p = 0.035), ICAM1 (r = 0.33, p = 0.02)], converters [IL1ß (r = 0.66, p = 0.004)], and non-converters [BMP6 (r = -0.96, p < 0.001), CALB1 (r = -0.98, p < 0.001), ICAM1 (r = 0.80, p = 0.003), SELE (r = 0.59, p = 0.026), SHBG (r = 0.99, p < 0.001), TNFRSF10C (r = 0.78, p = 0.001)]. CONCLUSIONS: CHR and non-converters demonstrated significantly larger ChP volumes compared to controls. Enlarged ChP was associated with neuroanatomical alterations and analyte markers functionally associated with the ChP. These findings suggest that the ChP may be a key an important biomarker in CHR.

Calculation of cerebral hemispheres volume values (grey matter, white matter and lateral ventricle) of sheep and goat: A stereological study.

Stereology is a discipline that allows us to obtain quantitative information about the geometric structure of three-dimensional objects. In this study, the volume of grey matter (GM), white matter (WM), and lateral ventricle (LV) of the cerebral hemispheres (CH) in sheep and goats were calculated. For this purpose, six healthy male sheep and goat brains (1-2 years old) without any anomaly were used. Brains were fixed with 10% formaldehyde in the skull. The skull was opened using standard anatomical dissection methods, and the brains were carefully removed. Brain weight and volume were measured (using Archimedes' principle) after the meninges were removed. The cerebral hemispheres were separated from the other parts of the brain by a section made in front of the rostral colliculus. In the same way, the weight and volume of the cerebral hemispheres were measured. Afterward, the cerebral hemispheres were blocked with agar, and transversal cross sections (from rostral to caudal) with an average thickness of 3.42 mm were taken from the cerebral hemispheres. Grey matter was stained with Berlin blue macroscopic staining method. The stained cross sections were scanned at 600 dpi resolution, and a point counting grid was placed on the images with the ImageJ software. Cavalieri's principle calculated the surface area and volume measurements of the grey matter, white matter, and lateral ventricle. GM, WM, and LV volumes in sheep and goat cerebral hemispheres were calculated as 54.94, 21.48 and 3.06 mL in sheep, 57.46, 24.13 and 3.12 mL in goats, respectively. The percentages of these structures in the total hemisphere volume were 71.83%, 28.17% and 4.00% in sheep, 70.42%, 29.58% and 3.82% in goats, respectively. Asymmetry was not observed in cerebral hemispheres in both species. A difference was found in the WM, LV and LV: CH ratios in the right/left comparison of the goat (p < 0.05). In comparing sheep and goats, a significant difference was observed in WM right, WM left, WM total, CH left and CH total (p < 0.05). In conclusion, the cerebral hemispheres' grey matter and white matter ratio are frequently used to diagnose neurodegenerative diseases. In recent years, the increase in neurodegenerative disease models in farm animals has been enormous. It is thought that these values obtained from healthy animals in the current study will be important for such experimental studies in the future.

Sex Difference in Cigarette-Smoking Status and Its Association with Brain Volumes Using Large-Scale Community-Representative Data.

BACKGROUND: Cigarette smoking is believed to accelerate age-related neurodegeneration. Despite significant sex differences in both smoking behaviors and brain structures, the active literature is equivocal in parsing out a sex difference in smoking-associated brain structural changes. OBJECTIVE: The current study examined subcortical and lateral ventricle gray matter (GM) volume differences among smokers, active, past, and never-smokers, stratified by sex. METHODS: The current study data included 1959 Dallas Heart Study (DHS) participants with valid brain imaging data. Stratified by gender, multiple-group comparisons of three cigarette-smoking groups were conducted to test whether there is any cigarette-smoking group differences in GM volumes of the selected regions of interest (ROIs). RESULTS: The largest subcortical GM volumetric loss and enlargement of the lateral ventricle were observed among past smokers for both females and males. However, these observed group differences in GM volumetric changes were statistically significant only among males after adjusting for age and intracranial volumes. CONCLUSIONS: The study findings suggest a sex difference in lifetime-smoking-associated GM volumetric changes, even after controlling for aging and intracranial volumes.

Effect comparison of neuroendoscopy versus microsurgery in the treatment of lateral ventricular tumors.

Purpose: We sought to reveal the clinical characteristics of lateral ventricle tumors and to evaluate the superior surgical procedure available. Methods: There involved a total of of 49 adult patients harboring lateral ventricle tumors in neurosurgery department of our hospital from January 2016 to March 2022. The patients enrolled were retrospectively analyzed, so are their clinical manifestations, pathological characteristics and surgical strategies. The patients were allocated into neuroendoscope group (11 cases) and microsurgery group (38 cases) according to the operation method. The two groups underwent a detailed evaluation of operation effectiveness and safety profile (operation time, intraoperative bleeding, surgical resection rate, postoperative complications) and economic indicators (postoperative hospital stay, hospital costs). Results: The neuroendoscope group demonstrated a markedly shorter operation time than the microsurgery group (p<0.05), with the amount of bleeding significantly less than the microsurgery group (p<0.01). However, there was no significant difference in the resection rate and postoperative complications between the two groups (p>0.05). Significant difference was found in the economic indicators (postoperative hospital stay and hospital costs) of the patients in the neuroendoscope group (p<0.05). Conclusion: Surgery intervention is regarded as the core treatment option for lateral ventricle tumors. Both microsurgery and neuroendoscopy are effective with safety profile. In the selected lateral ventricle tumor surgery, the application of neuroendoscopic surgery showed promising results, in terms of less intraoperative bleeding, and shorter operation time, postoperative hospital stays, and hospital costs. The selection of surgical approach and methods for lateral ventricle tumors is principally depended on the experience of neurosurgeon concerning the surgical approach and related neuroanatomy.

Microbial metabolites regulate social novelty via CaMKII neurons in the BNST.

Social novelty is a cognitive process that is essential for animals to interact strategically with conspecifics based on their prior experiences. The commensal microbiome in the gut modulates social behavior through various routes, including microbe-derived metabolite signaling. Short-chain fatty acids (SCFAs), metabolites derived from bacterial fermentation in the gastrointestinal tract, have been previously shown to impact host behavior. Herein, we demonstrate that the delivery of SCFAs directly into the brain disrupts social novelty through distinct neuronal populations. We are the first to observe that infusion of SCFAs into the lateral ventricle disrupted social novelty in microbiome-depleted mice without affecting brain inflammatory responses. The deficit in social novelty can be recapitulated by activating calcium/calmodulin-dependent protein kinase II (CaMKII)-labeled neurons in the bed nucleus of the stria terminalis (BNST). Conversely, chemogenetic silencing of the CaMKII-labeled neurons and pharmacological inhibition of fatty acid oxidation in the BNST reversed the SCFAs-induced deficit in social novelty. Our findings suggest that microbial metabolites impact social novelty through a distinct neuron population in the BNST.

Disrupted neurogenesis, gliogenesis, and ependymogenesis in the Ccdc85c knockout rat for hydrocephalus model.

Coil-coiled domain containing 85c (Ccdc85c) is a causative gene for congenital hydrocephalus and subcortical heterotopia with frequent brain hemorrhage. We established Ccdc85c knockout (KO) rats and investigated the roles of CCDC85C and intermediate filament protein expression, including nestin, vimentin, GFAP, and cytokeratin AE1/AE3 during the lateral ventricle development in KO rats to evaluate the role of this gene. We found altered and ectopic expression of nestin and vimentin positive cells in the wall of the dorso-lateral ventricle in the KO rats during development from the age of postnatal day (P) 6, whereas both protein expression became faint in the wild-type rats. In the KO rats, there was a loss of cytokeratin expression on the surface of the dorso-lateral ventricle with ectopic expression and maldevelopment of ependymal cells. Our data also revealed disturbed GFAP expression at postnatal ages. These findings indicate that lack of CCDC85C disrupts the proper expression of intermediate filament proteins (nestin, vimentin, GFAP, and cytokeratin), and CCDC85C is necessary for normal neurogenesis, gliogenesis, and ependymogenesis.

A Consideration of Optimal Head Position in Transsylvian Selective Amygdalohippocampectomy.

Transsylvian selective amygdalohippocampectomy (TSA) is one of the predominant surgical options for drug-resistant mesial temporal lobe epilepsy. The purpose of this article is to highlight the unique features of TSA and determine the setting to perform safe and secure TSA with special reference to the optimal head position. TSA should be performed via a small surgical corridor in the temporal stem that contains functionally important fiber tracts, including the uncinate fasciculus, the inferior fronto-occipital fasciculus, and the optic radiation. Graphical simulations proposed that low-degree (<30°) head rotation had the advantage of sufficiently opening the surgical field in TSA and may help surgical procedures within the limited exposure of the medial temporal structures. Inspection of the surgical videos implied that the collapse of the inferior horn was prevented in low-degree rotation, probably because the deformation due to the brain shift was minimized in the medial temporal structures. A simulation also implied that chin-up position had the advantage of resecting the tail of the hippocampus in a straightforward manner. We suggest that the setting is optimized in TSA with low-degree rotation and chin-up head position.

Inflammatory disequilibrium and lateral ventricular enlargement in treatment-resistant schizophrenia.

Treatment-resistant schizophrenia (TRS) patient respond poorly to antipsychotics. Inflammatory imbalance involving pro- and anti-inflammatory cytokines may play an important role in the mechanism of antipsychotic-medication response. This study aimed to investigate immune imbalance and how the latter relates to clinical manifestations in patients with TRS. The level of net inflammation was estimated by evaluating the immune-inflammatory response system and compensatory immune-regulatory reflex system (IRS/CIRS) in 52 patients with TRS, 47 with non-TRS, and 56 sex and age matched healthy controls. The immune biomarkers mainly included macrophagic M1, T helper, Th-1, Th-2, Th-17, and T regulatory cytokines and receptors. Plasma cytokine levels were measured using enzyme-linked immunosorbent assay. Psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS). Subcortical volumes were quantified using a 3-T Prisma Magnetic Resonance Imaging scanner. The results showed that (1) patients with TRS were characterized by activated pro-inflammatory cytokines and relatively insufficient anti-inflammatory cytokines, with an elevated IRS/CIRS ratio indicating a new homeostatic immune setpoint; (2) IRS/CIRS ratio was positively correlated with larger lateral ventricle volume and higher PANSS score in patients with TRS. Our findings highlighted the inflammatory disequilibrium as a potential pathophysiological process of TRS.

First-trimester choroid-plexus-to-lateral-ventricle disproportion and prediction of subsequent ventriculomegaly.

OBJECTIVE: Ventriculomegaly can be associated with long-term neurodevelopmental impairment. Prenatal diagnosis of ventriculomegaly is most commonly made at the routine second-trimester anomaly scan. The value of first-trimester ultrasound has expanded to early diagnosis and screening of fetal abnormalities. The objective of this study was to assess the predictive accuracy of first-trimester choroid-plexus-to-lateral-ventricle-or-head ratios for development of ventriculomegaly at a later gestational age. METHODS: This was a case-control study of fetuses with isolated ventriculomegaly diagnosed after 16 weeks' gestation and a control group of normal fetuses (without ventriculomegaly). The exclusion criteria included aneuploidy, genetic syndrome and/or other brain abnormality. Stored two-dimensional first-trimester ultrasound images were analyzed blindly offline and fetal biometry was performed in the axial view of the fetal head. The ratios of choroid plexus area (PA) to lateral ventricular area (VA), choroid plexus length (PL) to lateral ventricular length (VL), choroid plexus diameter (PD) to lateral ventricular diameter (VD) and PA to biparietal diameter (BPD) were measured at 11 + 0 to 13 + 6 weeks' gestation. Intra- and interobserver variability of measurement of these fetal head biometric parameters at 11 + 0 to 13 + 6 weeks' gestation were assessed in 20 normal fetuses using intraclass correlation coefficients with 95% CI. The accuracy of first-trimester biometric measurements for prediction of ventriculomegaly was assessed using the area under the receiver-operating-characteristics curves (AUC). RESULTS: The analysis included 683 singleton pregnancies, of which 102 fetuses were diagnosed with ventriculomegaly. Ventriculomegaly was mild in 86 (84.3%) cases and severe in the other 16 (15.7%). All first-trimester fetal choroid-plexus-to-lateral-ventricle/head ratios were significantly lower in cases with ventriculomegaly compared with controls (P < 0.001), with good inter- and intraobserver agreement (≥ 0.95) for the majority of the fetal head biometric parameters assessed. On adjusting for crown-rump length, optimism-adjusted AUC values obtained after cross-validation showed that both PL/VL ratio (AUC, 0.87 (95% CI, 0.73-0.98)) and PA/VA ratio (AUC, 0.90 (95% CI, 0.82-0.98)) had good predictive accuracy for severe ventriculomegaly. The PA/BPD ratio (AUC, 0.73 (95% CI, 0.54-0.90)) had modest predictive ability, which was significantly lower compared with that of the PA/VA ratio and PL/VL ratio (P = 0.003 and P = 0.001, respectively). The predictive accuracy of PD/VD ratio was low with an AUC of 0.65 (95% CI, 0.47-0.84). Optimism-adjusted AUC values obtained after cross-validation showed that PA/VA ratio offered the highest predictive accuracy for mild ventriculomegaly with an AUC of 0.84 (95% CI, 0.79-0.89), followed by PL/VL ratio (AUC, 0.82 (95% CI, 0.76-0.88)), PA/BPD ratio (AUC, 0.76 (95% CI, 0.69-0.82)) and PD/VD ratio (AUC, 0.75 (95% CI, 0.67-0.81)). Calibration plots showed that both PA/VA and PL/VL ratios had good calibration. CONCLUSION: First-trimester prediction of ventriculomegaly using ratios of fetal choroid plexus to lateral ventricle/head appears promising. Future prospective studies are needed to validate the predictive accuracy of these ultrasound markers as a screening tool for ventriculomegaly. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.