Diffusion tensor imaging study of pediatric patients with congenital hydrocephalus: 1-year postsurgical outcomes

Association of Glymphatic and White Matter Impairment With the Postoperative Outcome of Pediatric Hydrocephalus

BACKGROUND AND OBJECTIVES

Assessment of postoperative outcomes on pediatric hydrocephalus is critical for adjusting treatment strategies. The aim of this work was to investigate the ability of MRI metrics to predict postoperative outcomes.

METHODS

A total of 55 children with hydrocephalus who underwent MRI and ventriculoperitoneal shunt surgery were prospectively enrolled. MRI was also performed at 6 months postoperatively in 33 of the 55 children. A total of 92 controls matched for age and sex were enrolled and divided into preoperative and postoperative control groups. We calculated the diffusion tensor imaging along the perivascular space (DTI-ALPS) index, Evans index, and diffusion tensor imaging metrics. The ability of various metrics to predict postoperative outcomes was assessed using receiver operating characteristic curve analysis.

RESULTS

The DTI-ALPS index was significantly lower in patients with hydrocephalus than in controls. The abnormal DTI-ALPS index trended toward the normal range after surgery. Patients with lower preoperative DTI-ALPS index, lower fractional anisotropy (FA), and higher radial diffusivity in association fibers had less favorable short-term outcomes. Patients with worse long-term outcomes had lower postoperative DTI-ALPS index, higher postoperative Evans index, and lower FA and higher radial diffusivity in association fibers. Predictive performance was better when the DTI-ALPS index and FA in association fibers were used in combination than when either of these metrics was used alone.

CONCLUSION

The DTI-ALPS index and FA in association fibers provided complementary information for prognostic assessment after the ventriculoperitoneal shunt surgery on pediatric hydrocephalus. A combination of DTI-ALPS index and FA would improve our ability to predict postoperative outcomes in these patients.

Structural and functional connectivity in hydrocephalus: a scoping review

Optimizing the treatment of hydrocephalus remains a major challenge in adult and pediatric neurosurgery. Currently, clinical treatment relies heavily on anatomic imaging of ventricular size and clinical presentation. The emergence of functional and structural brain connectivity imaging has provided the basis for a new paradigm in the management of hydrocephalus. Here we review the pertinent advances in this field. Following PRISMA-ScR guidelines for scoping reviews, we searched PubMed for relevant literature from 1994 to April 2023 using hydrocephalus and MRI-related terms. Included articles reported original MRI data on human subjects with hydrocephalus, while excluding non-English or pre-1994 publications that didn't match the study framework. The review identified 44 studies that investigated functional and/or structural connectivity using various MRI techniques across different hydrocephalus populations. While there is significant heterogeneity in imaging technology and connectivity analysis, there is broad consensus in the literature that 1) hydrocephalus is associated with disruption of functional and structural connectivity, 2) this disruption in cerebral connectivity can be further associated with neurologic compromise 3) timely treatment of hydrocephalus restores both cerebral connectivity and neurologic compromise. The robustness and consistency of these findings vary as a function of patient age, hydrocephalus etiology, and the connectivity region of interest studied. Functional and structural brain connectivity imaging shows potential as an imaging biomarker that may facilitate optimization of hydrocephalus treatment. Future research should focus on standardizing regions of interest as well as identifying connectivity analysis most pertinent to clinical outcome.

The Construction of a Predictive Composite Index for Decision-Making of CSF Diversion Surgery in Pediatric Patients following Prenatal Myelomeningocele Repair

BACKGROUND AND PURPOSE

There is a wide range of clinical and radiographic factors affecting individual surgeons' ultimate decision for CSF diversion for pediatric patients following prenatal myelomeningocele repair. Our aim was to construct a composite index (CSF diversion surgery index) that integrates conventional clinical measures and neuroimaging biomarkers to predict CSF diversion surgery in these pediatric patients.

MATERIALS AND METHODS

This was a secondary retrospective analysis of data from 33 patients with prenatal myelomeningocele repair (including 14 who ultimately required CSF diversion surgery). Potential independent variables, including the Management of Myelomeningocele Study Index (a dichotomized variable based on the shunt-placement criteria from the Management of Myelomeningocele Study), postnatal DTI measures (fractional anisotropy and mean diffusivity in the genu of the corpus callosum and the posterior limb of internal capsule), fronto-occipital horn ratio at the time of DTI, gestational ages, and sex, were evaluated using stepwise logistic regression analysis to identify the most important predictors.

RESULTS

The CSF diversion surgery index model showed that the Management of Myelomeningocele Study Index and fractional anisotropy in the genu of the corpus callosum were significant predictors (P < .05) of CSF diversion surgery. The predictive value of the CSF diversion surgery index was also affected by fractional anisotropy in the posterior limb of the internal capsule and sex with marginal effect (.05<P < .10), but not by the fronto-occipital horn ratio (P > .10). The overall CSF diversion surgery index model fit the data well with statistical significance (eg, likelihood ratio: P < .001), with the performance (sensitivity = 78.6%; specificity = 86.5%, overall accuracy = 84.8%) superior to all individual indices in sensitivity and overall accuracy, and most of the individual indices in specificity.

CONCLUSIONS

The CSF diversion surgery index model outperformed all single predictor models and, with additional validation, may potentially be developed and incorporated into a sensitive and robust clinical tool to assist clinicians in hydrocephalus management.

Diffusion Tensor Imaging Profiles Can Distinguish Diffusivity and Neural Properties of White Matter Injury in Hydrocephalus vs. Non-hydrocephalus Using a Strategy of a Periodic Table of DTI Elements

Background:

The aim of this study was to create a simplistic taxonomy to improve transparency and consistency in, and reduce complexity of, interpreting diffusion tensor imaging (DTI) profiles in white matter disruption. Using a novel strategy of a periodic table of DTI elements, we examined if DTI profiles could demonstrate neural properties of disruption sufficient to characterize white matter changes specific for hydrocephalus vs. non-hydrocephalus, and to distinguish between cohorts of neural injury by their differing potential for reversibility.

Methods

DTI datasets from three clinical cohorts representing pathological milestones from reversible to irreversible brain injury were compared to those of healthy controls at baseline, over time and with interventions. The final dataset comprised patients vs. controls in the following groupings: mild traumatic brain injury (mTBI), n = 24 vs. 27, normal pressure hydrocephalus (NPH), n = 16 vs. 9 and Alzheimer's disease (AD), n = 27 vs. 47. We generated DTI profiles from fractional anisotropy (FA) and mean, axial and radial diffusivity measures (MD, L1 and L2 and 3 respectively), and constructed an algorithm to map changes consistently to a periodic table of elements, which fully described their diffusivity and neural properties.

Results

Mapping tissue signatures to a periodic table of DTI elements rapidly characterized cohorts by their differing patterns of injury. At baseline, patients with mTBI displayed the most preserved tracts. In NPH, the magnitude of changes was dependent on “familial” DTI neuroanatomy, i.e., potential for neural distortion from risk of ventriculomegaly. With time, patients with Alzheimer's disease were significantly different to controls across multiple measures. By contrast, patients with mTBI showed both loss of integrity and pathophysiological processes of neural repair. In NPH, some patterns of injury, such as “stretch/compression” and “compression” were more reversible following intervention than others; these neural profile properties suggested “microstructural resilience” to injury.

Conclusion

Using the novel strategy of a periodic table of DTI elements, our study has demonstrated it is possible to distinguish between different cohorts along the spectrum of brain injury by describing neural profile properties of white matter disruption. Further work to contribute datasets of disease toward this proposed taxonomic framework would enhance the translatability of DTI profiles to the clinical-research interface.

A diffusion tensor imaging analysis of white matter microstructures in non-operated craniosynostosis patients

PURPOSE

In 7 to 15-year-old operated syndromic craniosynostosis patients, we have shown the presence of microstructural anomalies in brain white matter by using DTI. To learn more about the cause of these anomalies, the aim of the study is to determine diffusivity values in white matter tracts in non-operated syndromic craniosynostosis patients aged 0-2 years compared to healthy controls.

METHODS

DTI datasets of 51 non-operated patients with syndromic craniosynostosis with a median [IQR] age of 0.40 [0.25] years were compared with 17 control subjects with a median of 1.20 [0.85] years. Major white matter tract pathways were reconstructed with ExploreDTI from MRI brain datasets acquired on a 1.5 T MRI system. Eigenvalues of these tract data were examined, with subsequent assessment of the affected tracts. Having syndromic craniosynostosis (versus control), gender, age, frontal occipital horn ratio (FOHR), and tract volume were treated as independent variables.

RESULTS

ʎ₂ and ʎ₃ of the tracts genu of the corpus callosum and the hippocampal segment of the cingulum bundle show a ƞ² > 0.14 in the comparison of patients vs controls, which indicates a large effect on radial diffusivity. Subsequent linear regressions on radial diffusivity of these tracts show that age and FOHR are significantly associated interacting factors on radial diffusivity (p < 0.025).

CONCLUSION

Syndromic craniosynostosis shows not to be a significant factor influencing the major white matter tracts. Enlargement of the ventricles show to be a significant factor on radial diffusivity in the tracts corpus callosum genu and the hippocampal segment of the cingulate bundle.

CLINICAL TRIAL REGISTRATION

MEC-2014-461.

Prevalence of supratentorial anomalies assessed by magnetic resonance imaging in fetuses with open spina bifida

OBJECTIVES

To determine the prevalence of brain anomalies at the time of preoperative magnetic resonance imaging (MRI) assessment in fetuses eligible for prenatal open spina bifida (OSB) repair, and to explore the relationship between brain abnormalities and features of the spinal defect.

METHODS

This was a retrospective cross-sectional study, conducted in three fetal medicine centers, of fetuses eligible for OSB fetal surgery repair between January 2009 and December 2019. MRI images obtained as part of the presurgical assessment were re-evaluated by two independent observers, blinded to perinatal results, to assess: (1) the type and area of the defect and its anatomical level; (2) the presence of any structural central nervous system (CNS) anomaly and abnormal ventricular wall; and (3) fetal head and brain biometry. Binary regression analyses were performed and data were adjusted for type of defect, upper level of the lesion (ULL), gestational age (GA) at MRI and fetal medicine center. Multiple logistic regression analysis was performed in order to identify lesion characteristics and brain anomalies associated with a higher risk of presence of abnormal corpus callosum (CC) and/or heterotopia.

RESULTS

Of 115 fetuses included, 91 had myelomeningocele and 24 had myeloschisis. Anatomical level of the lesion was thoracic in seven fetuses, L1-L2 in 13, L3-L5 in 68 and sacral in 27. Median GA at MRI was 24.7 (interquartile range, 23.0-25.7) weeks. Overall, 52.7% of cases had at least one additional brain anomaly. Specifically, abnormal CC was observed in 50.4% of cases and abnormality of the ventricular wall in 19.1%, of which 4.3% had nodular heterotopia. Factors associated independently with higher risk of abnormal CC and/or heterotopia were non-sacral ULL (odds ratio (OR), 0.51 (95% CI, 0.26-0.97); P = 0.043), larger ventricular width (per mm) (OR, 1.23 (95% CI, 1.07-1.43); P = 0.005) and presence of abnormal cavum septi pellucidi (OR, 3.76 (95% CI, 1.13-12.48); P = 0.031).

CONCLUSIONS

Half of the fetuses assessed for OSB repair had an abnormal CC and/or an abnormal ventricular wall prior to prenatal repair. The likelihood of brain abnormalities was increased in cases with a non-sacral lesion and wider lateral ventricles. These findings highlight the importance of a detailed preoperative CNS evaluation of fetuses with OSB. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Brain Network Connectivity and Executive Function in Children with Previous Infantile Hydrocephalus

INTRODUCTION

Infantile hydrocephalus is a condition in which there is an abnormal build-up of cerebrospinal fluid in the ventricles within the first few months of life, which puts pressure on surrounding brain tissues. Compression of the developing brain increases the risk of secondary brain injury and cognitive disabilities.

METHODS

In this study, we used diffusion-weighted imaging and resting-state functional MRI to investigate the effects of ventricle dilatation on structural and functional brain networks in children with shunted infantile hydrocephalus and examined how these brain changes may impact executive function.

RESULTS

We found that children with hydrocephalus have altered structural and functional connectivity between and within large-scale networks. Moreover, hyperconnectivity between the ventral attention and default mode network in children with hydrocephalus correlated with reduced executive function scores. Compared to typically developing age-matched control participants, our patient population also had lower fractional anisotropy in posterior white matter.

DISCUSSION

Overall, these findings suggest that infantile hydrocephalus has long-term effects on brain network connectivity, white matter development, and executive function in children at school-age. Future work will examine the relationship between ventricular volumes prior to shunt placement in infancy and brain network development throughout childhood.

Microstructural Periventricular White Matter Injury in Post-hemorrhagic Ventricular Dilatation

BACKGROUND AND OBJECTIVES

The neurologic deficits of neonatal post-hemorrhagic hydrocephalus (PHH) have been linked to periventricular white matter injury. To improve understanding of PHH-related injury, diffusion basis spectrum imaging (DBSI) was applied in neonates, modeling axonal and myelin integrity, fiber density, and extrafiber pathologies. Objectives included characterizing DBSI measures in periventricular tracts, associating measures with ventricular size, and examining MRI findings in the context of postmortem white matter histology from similar cases.

METHODS

A prospective cohort of infants born very preterm underwent term equivalent MRI, including infants with PHH, high-grade intraventricular hemorrhage without hydrocephalus (IVH), and controls (very preterm [VPT]). DBSI metrics extracted from the corpus callosum, corticospinal tracts, and optic radiations included fiber axial diffusivity, fiber radial diffusivity, fiber fractional anisotropy, fiber fraction (fiber density), restricted fractions (cellular infiltration), and nonrestricted fractions (vasogenic edema). Measures were compared across groups and correlated with ventricular size. Corpus callosum postmortem immunohistochemistry in infants with and without PHH assessed intra- and extrafiber pathologies.

RESULTS

Ninety-five infants born very preterm were assessed (68 VPT, 15 IVH, 12 PHH). Infants with PHH had the most severe white matter abnormalities and there were no consistent differences in measures between IVH and VPT groups. Key tract-specific white matter injury patterns in PHH included reduced fiber fraction in the setting of axonal or myelin injury, increased cellular infiltration, vasogenic edema, and inflammation. Specifically, measures of axonal injury were highest in the corpus callosum; both axonal and myelin injury were observed in the corticospinal tracts; and axonal and myelin integrity were preserved in the setting of increased extrafiber cellular infiltration and edema in the optic radiations. Increasing ventricular size correlated with worse DBSI metrics across groups. On histology, infants with PHH had high cellularity, variable cytoplasmic vacuolation, and low synaptophysin marker intensity.

DISCUSSION

PHH was associated with diffuse white matter injury, including tract-specific patterns of axonal and myelin injury, fiber loss, cellular infiltration, and inflammation. Larger ventricular size was associated with greater disruption. Postmortem immunohistochemistry confirmed MRI findings. These results demonstrate DBSI provides an innovative approach extending beyond conventional diffusion MRI for investigating neuropathologic effects of PHH on neonatal brain development.

A multimodal approach to the study of children treated for posterior fossa tumor: A review of the literature and a pilot study

OBJECTIVE

The aims of the present study were: (1) to review the literature on long-lasting cognitive sequelae in children treated for Posterior Fossa Tumor and (2) to investigate anatomic functional relations in a case series of 7 children treated for PFT using magnetic resonance imaging (MRI) post-processing methods.

METHODS

We retrospectively analyzed MRIs of children who underwent complete surgical resection of PFT and performed extensive neuropsychological evaluation. Tumor, ventricular volumes, and VPS insertion site were drawn on T1 volumetric MRI scans and normalized to a pediatric template. Children showed worse performances on tasks tapping executive functions, memory, visuo-motor precision, and expressive language.

RESULTS

Volumes of interest related to these functions showed a maximum overlap on the left vermis and the lateral ventricle enlargement, except for impaired narrative fluency -which was associated with left lateral ventricle enlargement- and narrative memory -which was related to the right vermis and the enlarged fourth ventricle.

CONCLUSION

Results suggest that anatomic functional relations in children treated for PFT are related to a combination of different pathophysiological factors.

Neurodevelopmental outcomes after ventriculoperitoneal shunt placement in children with non-infectious hydrocephalus: a meta-analysis

BACKGROUND

Hydrocephalus is diagnosed when an accumulating amount of cerebrospinal fluid (CSF) fails to circulate and/or absorbed in the ventricular system. Based on its etiology, hydrocephalus can be classified into infectious and non-infectious hydrocephalus. In children, non-infectious hydrocephalus includes congenital hydrocephalus, posthemorrhagic hydrocephalus, neural tube defect-related hydrocephalus, and tumor-related hydrocephalus. Regardless of the cause, a CSF diversion device is placed to divert the excess fluid from the ventricles into peritoneal cavity. Among all, ventriculoperitoneal (VP) shunt is arguably the most commonly used CSF diversion device to date. Until now, the long-term neurodevelopmental impact of VP shunt placement in non-infectious hydrocephalus patients remained unclear.

OBJECTIVE

This study aims to evaluate the neurodevelopmental outcomes in children with non-infectious hydrocephalus who had VP shunt placement.

MATERIALS AND METHODS

Systematic searches were performed using PubMed, Google Scholar, Scopus databases, and reference lists. Publications that fulfilled the inclusion criteria were included in the meta-analysis. Calculation of Mantel-Haezel risk ratio (RR) was applied, and heterogeneity index (I²) test was used to evaluate the existence of heterogeneity in all studies. Risk of bias was assessed based on the criteria from the Newcastle-Ottawa Scale (NOS).

RESULTS

Of the 1929 studies identified, 12 publications were concluded to have fulfilled the inclusion criteria. Results from the meta-analysis showed that the risks of cerebral palsy, visual and hearing impairment, epilepsy, or seizures are significantly higher in children with non-infectious hydrocephalus who already had VP shunt placement (shunted non-infectious hydrocephalus, S-NIH) compared to that of the healthy control. The meta-analysis on intelligent quotient (IQ) and mental development index (MDI) showed that S-NIH children tend to score lower IQ and acquire risk of having mental development delay. On motoric development, S-NIH children scored lower motoric score and have significantly higher risk of motor development delay compared to control. Although normal children tend to have more internalizing behavior compared to S-NIH children, overall assessment on the risk of behavioral abnormalities showed that the differences between these two groups are insignificant.

CONCLUSION

S-NIH children have significantly higher risks of disabilities and mental and motoric development delays; thus, planning on continuous rehabilitation for children with non-infectious hydrocephalus who already had placement of VP shunt is important to acquire their optimum potentials and quality of life.

Diffusion tensor imaging in children following prenatal myelomeningocele repair and its predictive value for the need and timing of subsequent CSF diversion surgery for hydrocephalus

OBJECTIVE

The aim of this study was to investigate diffusion tensor imaging (DTI), an objective and noninvasive neuroimaging technique, for its potential as an imaging biomarker to predict the need and timing of CSF diversion surgery in patients after prenatal myelomeningocele (MMC) repair.

METHODS

This was a retrospective analysis of data based on 35 pediatric patients after prenatal MMC repair (gestational age at birth 32.68 ± 3.42 weeks, range 24-38 weeks; 15 females and 20 males). A logistic regression analysis was used to classify patients to determine the need for CSF diversion surgery. The model performance was compared between using the frontooccipital horn ratio (FOHR) alone and using the FOHR combined with DTI values (the genu of the corpus callosum [gCC] and the posterior limb of the internal capsule [PLIC]). For patients who needed to be treated surgically, timing of the procedure was used as the clinical outcome to test the predictive value of DTI acquired prior to surgery based on a linear regression analysis.

RESULTS

Significantly lower fractional anisotropy (FA) values in the gCC (p = 0.014) and PLIC (p = 0.037) and higher mean diffusivity (MD) values in the gCC (p = 0.013) were found in patients who required CSF diversion surgery compared with those who did not require surgery (all p values adjusted for age). Based on the logistic regression analysis, the FOHR alone showed an accuracy of performance of 0.69 and area under the receiver operating characteristic curve (AUC) of 0.60. The performance of the model was higher when DTI measures were used in the logistic regression model (accuracy = 0.77, AUC = 0.84 for using DTI values in gCC; accuracy = 0.75, AUC = 0.84 for using DTI values in PLIC). Combining the DTI values of the gCC or PLIC and FOHR did not improve the model performance when compared with using the DTI values alone. In patients who needed CSF diversion surgery, significant correlation was found between DTI values in the gCC and the time interval between imaging and surgery (FA: ρ = 0.625, p = 0.022; MD: ρ = -0.6830, p = 0.010; both adjusted for age and FOHR).

CONCLUSIONS

The authors' data demonstrated that DTI could potentially serve as an objective biomarker differentiating patients after prenatal MMC repair regarding those who may require surgery for MMC-associated hydrocephalus. The predictive value for the need and timing of CSF diversion surgery is highly clinically relevant for improving and optimizing decision-making for the treatment of hydrocephalus in this patient population.

Tract-Specific Relationships Between Cerebrospinal Fluid Biomarkers and Periventricular White Matter in Posthemorrhagic Hydrocephalus of Prematurity

BACKGROUND

Posthemorrhagic hydrocephalus (PHH) is associated with neurological morbidity and complex neurosurgical care. Improved tools are needed to optimize treatments and to investigate the developmental sequelae of PHH.

OBJECTIVE

To examine the relationship between diffusion magnetic resonance imaging (dMRI) and cerebrospinal fluid (CSF) biomarkers of PHH.

METHODS

A total of 14 preterm (PT) infants with PHH and 46 controls were included. PT CSF was collected at temporizing surgery in PHH infants (PHH PT CSF) or lumbar puncture in controls. Term-equivalent age (TEA) CSF was acquired via implanted device or at permanent CSF diversion surgery in PHH (PHH-TEA-CSF) or lumbar puncture in controls. TEA dMRI scans were used to measure fractional anisotropy (FA) and mean diffusivity (MD) in the genu of corpus callosum (gCC), posterior limb of internal capsule (PLIC), and optic radiations (OPRA). Associations between dMRI measures and CSF amyloid precursor protein (APP), neural cell adhesion-1 (NCAM-1), and L1 cell adhesion molecule (L1CAM) were assessed using Pearson correlations.

RESULTS

APP, NCAM-1, and L1CAM were elevated over controls in PHH-PT-CSF and PHH-TEA-CSF. dMRI FA and MD differed between control and PHH infants across all tracts. PHH-PT-CSF APP levels correlated with gCC and OPRA FA and PLIC MD, while L1CAM correlated with gCC and OPRA FA. In PHH-TEA-CSF, only L1CAM correlated with OPRA MD.

CONCLUSION

Tract-specific associations were observed between dMRI and CSF biomarkers at the initiation of PHH treatment. dMRI and CSF biomarker analyses provide innovative complementary methods for examining PHH-related white matter injury and associated developmental sequelae.

MR Elastography demonstrates reduced white matter shear stiffness in early-onset hydrocephalus

INTRODUCTION

Hydrocephalus that develops early in life is often accompanied by developmental delays, headaches and other neurological deficits, which may be associated with changes in brain shear stiffness. However, noninvasive approaches to measuring stiffness are limited. Magnetic Resonance Elastography (MRE) of the brain is a relatively new noninvasive imaging method that provides quantitative measures of brain tissue stiffness. Herein, we aimed to use MRE to assess brain stiffness in hydrocephalus patients compared to healthy controls, and to assess its associations with ventricular size, as well as demographic, shunt-related and clinical outcome measures.

METHODS

MRE was collected at two imaging sites in 39 hydrocephalus patients and 33 healthy controls, along with demographic, shunt-related, and clinical outcome measures including headache and quality of life indices. Brain stiffness was quantified for whole brain, global white matter (WM), and lobar WM stiffness. Group differences in brain stiffness between patients and controls were compared using two-sample t-tests and multivariable linear regression to adjust for age, sex, and ventricular volume. Among patients, multivariable linear or logistic regression was used to assess which factors (age, sex, ventricular volume, age at first shunt, number of shunt revisions) were associated with brain stiffness and whether brain stiffness predicts clinical outcomes (quality of life, headache and depression).

RESULTS

Brain stiffness was significantly reduced in patients compared to controls, both unadjusted (p ≤ 0.002) and adjusted (p ≤ 0.03) for covariates. Among hydrocephalic patients, lower stiffness was associated with older age in temporal and parietal WM and whole brain (WB) (beta (SE): -7.6 (2.5), p = 0.004; -9.5 (2.2), p = 0.0002; -3.7 (1.8), p = 0.046), being female in global and frontal WM and WB (beta (SE): -75.6 (25.5), p = 0.01; -66.0 (32.4), p = 0.05; -73.2 (25.3), p = 0.01), larger ventricular volume in global, and occipital WM (beta (SE): -11.5 (3.4), p = 0.002; -18.9 (5.4), p = 0.0014). Lower brain stiffness also predicted worse quality of life and a higher likelihood of depression, controlling for all other factors.

CONCLUSIONS

Brain stiffness is reduced in hydrocephalus patients compared to healthy controls, and is associated with clinically-relevant functional outcome measures. MRE may emerge as a clinically-relevant biomarker to assess the neuropathological effects of hydrocephalus and shunting, and may be useful in evaluating the effects of therapeutic alternatives, or as a supplement, of shunting.

Cerebellitis as a neurosurgical disease in pediatrics

The diagnostic evaluation and role of neurosurgery in the treatment of cerebellitis is unclear. We explore the diagnostic evaluation and subsequent role of neurosurgical intervention in pediatric cerebellitis in a case series, highlighting the diagnostic work up and treatments applied. A retrospective review was conducted of all pediatricpatients diagnosed with cerebellitis for whom neurosurgery was consulted at a single center from June 2008 to February 2019. Nine patients, four males (44.4%) and five females (55.6%) were identified. Common presenting symptoms were headache (n = 6, 66.7%), emesis (n = 5, 55.6%), and altered mental status (n = 4, 44.4%). Six (66.7%) had associated infections. Imaging abnormalities included tonsillar ectopia (n = 8, 88.9%), bilateral cerebellar T2 hyperintensity (n = 6, 66.7%), and obstructive hydrocephalus (n = 6, 66.7%). Management included antibiotics, antivirals, corticosteroids, mannitol, and hypertonic saline. Four (44.4%) required external ventricular drain (EVD) placement for a mean 11 days (SD 6.8, range 4-20) for hydrocephalus; none required additional neurosurgical interventions. Seven patients (77.8%) required ICU care for a mean 11.7 days (SD 14.0 range 1-42). At follow-up (mean 20.8 months, SD 28.7, range 0.6-64.9), two patients (n = 2, 22.2%) recovered completely, and six (66.7%) were functionally dependent (mRS > 2); the most common residual deficit was cognitive impairment (n = 5, 55.6%). Neurosurgical consultation should be considered in pediatric patients with cerebellitis. In our experience, temporary CSF diversion via an EVD is employed nearly half of the time. The presence of hydrocephalus requiring neurosurgical intervention may be a predictor of severe disease and poor outcome.

Not all ventriculomegaly is created equal: diagnostic overview of fetal, neonatal and pediatric ventriculomegaly

Fetal ventriculomegaly refers to a condition in which there is enlargement of the ventricular spaces, typically on prenatal ultrasound. It can be associated with other CNS or extra-CNS abnormalities, and this relationship is crucial to understand as it affects overall neonatal outcome. Isolated ventriculomegaly has been described in the literature with variable clinical outcome. Typically, outcome is based on the etiology and degree of ventriculomegaly. When associated with a pathologic condition, ventriculomegaly can be a result of hydrocephalus. While initial diagnosis is usually made on prenatal ultrasound, fetal magnetic resonance imaging is preferred to further elucidate any associated CNS malformations. In this paper, the authors aim to provide a comprehensive review of the diagnosis, associated etiologies, prognosis, and treatment options related to fetal, neonatal, and pediatric ventriculomegaly and hydrocephalus. In addition, preliminary data is provided from our institutional cohort of patients with a prenatal diagnosis of ventriculomegaly followed through the perinatal period.

Abnormal anisotropic diffusion properties in pediatric myelomeningocele patients treated with fetal surgery: an initial DTI study

PURPOSE

To investigate white matter microstructural abnormality based on diffusion tensor imaging (DTI) in pediatric patients with fetal repair for myelomeningocele (MMC).

METHODS

This was a retrospective analysis of DTI data from 8 pediatric patients with prenatal MMC repair (age range 1.64-33.70 months; sex 3F/5M) and 8 age-matched controls (age 2.24-31.20 months; sex 5F/2M). All participants were scanned on 1.5T GE Signa MR scanner (GE Healthcare, Milwaukee, WI) with the same sequence specifications. Two DTI measures, including fractional anisotropy (FA) and mean diffusivity (MD), were calculated from the genu of corpus callosum (gCC) and the posterior limb of internal capsule (PLIC). DTI values and fronto-occipital horn ratio (FOHR) were tested for group difference based on two-tailed paired t test.

RESULTS

The ventricle size based on FOHR in patients with prenatal MMC repair was significantly larger than that in the age-matched control group (p < 0.001). Statistically significant group difference in DTI (lower FA and higher MD in patient group) was found in gCC (p = 0.007 and 0.003, respectively). A trend level increase in MD was also found (p = 0.065) in PLIC in patients when compared with the age-matched controls.

CONCLUSION

Our data showed white matter abnormality based on DTI in pediatric patient with fetal repair for MMC. The sensitivity of DTI in detecting white matter abnormality, as shown in the present study, may help to serve as an imaging biomarker for assessing hydrocephalus and improve and optimize decision making for the treatment of hydrocephalus in this patient population.

Automatic volumetry of cerebrospinal fluid and brain volume in severe paediatric hydrocephalus, implementation and clinical course after intervention

BACKGROUND

In childhood hydrocephalus, both the amount of cerebrospinal fluid and the brain volume are relevant for the prognosis of the development and for therapy monitoring. Since classical planar measurements of ventricular size are subject to strong limitations, imprecise and neglect brain volume, 3D volumetry is most desirable. We used and evaluated the robust segmentation algorithms of the freely available FSL-toolbox in paediatric hydrocephalus patients before and after specific therapy.

METHODS

Retrospectively 76 pre- and postoperative high-resolution T2-weighted MRI sequences (true FISP, 1 mm isovoxel) were analyzed in 38 patients with paediatric hydrocephalus (mean 4.4 ± 5.1 years) who underwent surgical treatment (ventriculo-peritoneal (VP) shunt n = 22, endoscopic third ventriculostomy (ETV) n = 16). After preprocessing, the 3D-datasets were skull stripped to estimate the inner skull surface. Following, a 2 class segmentation into different tissue types (brain matter and CSF) was performed. The volumes of CSF and brain were calculated.

RESULTS

The method could be implemented in an automated fashion in all 76 MRIs. In the VP shunt cohort, the amount of CSF (p < 0.001) decreased. Consecutively brain volume increased significantly (p < 0.001). Following ETV, CSF volume (p = 0.019) decreased significantly (p = 0.012) although the reduction was less pronounced than after shunt implantation. Brain volume expanded (p = 0.02).

CONCLUSION

A reliable automated segmentation of CSF and brain could be performed with the implemented algorithm. The method was able to track changes after therapy and detected significant differences in CSF and brain volumes after shunting and after ETV.

Impaired neural differentiation and glymphatic CSF flow in the Ccdc39 rat model of neonatal hydrocephalus: genetic interaction with L1cam

Neonatal hydrocephalus affects about one child per 1000 births and is a major congenital brain abnormality. We previously discovered a gene mutation within the coiled-coil domain-containing 39 (Ccdc39) gene, which causes the progressive hydrocephalus (prh) phenotype in mice due to lack of ependymal-cilia-mediated cerebrospinal fluid (CSF) flow. In this study, we used CRISPR/Cas9 to introduce the Ccdc39 gene mutation into rats, which are more suitable for imaging and surgical experiments. The Ccdc39^prh/prh mutants exhibited mild ventriculomegaly at postnatal day (P)5 that progressed into severe hydrocephalus by P11 (P<0.001). After P11, macrophage and neutrophil invasion along with subarachnoid hemorrhage were observed in mutant brains showing reduced neurofilament density, hypomyelination and increased cell death signals compared with wild-type brains. Significantly more macrophages entered the brain parenchyma at P5 before hemorrhaging was noted and increased expression of a pro-inflammatory factor (monocyte chemoattractant protein-1) was found in the cortical neural and endothelial cells in the mutant brains at P11. Glymphatic-mediated CSF circulation was progressively impaired along the middle cerebral artery from P11 as mutants developed severe hydrocephalus (P<0.001). In addition, Ccdc39^prh/prh mutants with L1 cell adhesion molecule (L1cam) gene mutation, which causes X-linked human congenital hydrocephalus, showed an accelerated early hydrocephalus phenotype (P<0.05-0.01). Our findings in Ccdc39^prh/prh mutant rats demonstrate a possible causal role of neuroinflammation in neonatal hydrocephalus development, which involves impaired cortical development and glymphatic CSF flow. Improved understanding of inflammatory responses and the glymphatic system in neonatal hydrocephalus could lead to new therapeutic strategies for this condition.

This article has an associated First Person interview with the joint first authors of the paper.

Summary: Glymphatic CSF circulation and development of the cerebral cortex are impaired in our new genetic rat model of neonatal hydrocephalus with the onset of parenchymal inflammation and hemorrhage.

MR diffusion changes in the perimeter of the lateral ventricles demonstrate periventricular injury in post-hemorrhagic hydrocephalus of prematurity

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Diffusion MRI demonstrates PHH is associated with LVP microstructural injury.

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The greatest PHH-associated disruption occurs at the frontal and occipital horns.

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Greater ventricular size is associated with greater disruption.

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dMRI may provide useful biomarkers for PHH monitoring and intervention.

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The region of LVP injury encompasses neuroprogenitor regions.

Objectives

Injury to the preterm lateral ventricular perimeter (LVP), which contains the neural stem cells responsible for brain development, may contribute to the neurological sequelae of intraventricular hemorrhage (IVH) and post-hemorrhagic hydrocephalus of prematurity (PHH). This study utilizes diffusion MRI (dMRI) to characterize the microstructural effects of IVH/PHH on the LVP and segmented frontal-occipital horn perimeters (FOHP).

Study design

Prospective study of 56 full-term infants, 72 very preterm infants without brain injury (VPT), 17 VPT infants with high-grade IVH without hydrocephalus (HG-IVH), and 13 VPT infants with PHH who underwent dMRI at term equivalent. LVP and FOHP dMRI measures and ventricular size-dMRI correlations were assessed.

Results

In the LVP, PHH had consistently lower FA and higher MD and RD than FT and VPT (p<.050). However, while PHH FA was lower, and PHH RD was higher than their respective HG-IVH measures (p<.050), the MD and AD values did not differ. In the FOHP, PHH infants had lower FA and higher RD than FT and VPT (p<.010), and a lower FA than the HG-IVH group (p<.001). While the magnitude of AD in both the LVP and FOHP were consistently less in the PHH group on pairwise comparisons to the other groups, the differences were not significant (p>.050). Ventricular size correlated negatively with FA, and positively with MD and RD (p<.001) in both the LVP and FOHP. In the PHH group, FA was lower in the FOHP than in the LVP, which was contrary to the observed findings in the healthy infants (p<.001). Nevertheless, there were no regional differences in AD, MD, and RD in the PHH group.

Conclusion

HG-IVH and PHH results in aberrant LVP/FOHP microstructure, with prominent abnormalities among the PHH group, most notably in the FOHP. Larger ventricular size was associated with greater magnitude of abnormality. LVP/FOHP dMRI measures may provide valuable biomarkers for future studies directed at improving the management and neurological outcomes of IVH/PHH.

Feasibility of fast brain diffusion MRI to quantify white matter injury in pediatric hydrocephalus

OBJECTIVE

Traditionally, diffusion MRI (dMRI) has been performed in parallel with high-resolution conventional MRI, which requires long scan times and may require sedation or general anesthesia in infants and young children. Conversely, fast brain MRI permits image acquisition without the need for sedation, although its short pulse sequences, susceptibility to motion artifact, and contrast resolution have limited its use to assessing ventricular size or major structural variations. Here, the authors demonstrate the feasibility of leveraging a 3-direction fast brain MRI protocol to obtain reliable dMRI measures.

METHODS

Fast brain MRI with 3-direction dMRI was performed in infants and children before and after hydrocephalus treatment. Regions of interest in the posterior limbs of the internal capsules (PLICs) and the genu of the corpus callosum (gCC) were drawn on diffusion-weighted images, and mean diffusivity (MD) data were extracted. Ventricular size was determined by the frontal occipital horn ratio (FOHR). Differences between and within groups pre- and posttreatment, and FOHR-MD correlations were assessed.

RESULTS

Of 40 patients who met inclusion criteria (median age 27.5 months), 15 (37.5%), 17 (42.5%), and 8 (20.0%) had posthemorrhagic hydrocephalus (PHH), congenital hydrocephalus (CH), or no intracranial abnormality (controls), respectively. A hydrocephalus group included both PHH and CH patients. Prior to treatment, the FOHR (p < 0.001) and PLIC MD (p = 0.027) were greater in the hydrocephalus group than in the controls. While the mean gCC MD in the hydrocephalus group (1.10 × 10-3 mm2/sec) was higher than that of the control group (0.98), the difference was not significant (p = 0.135). Following a median follow-up duration of 14 months, decreases in FOHR, PLIC MD, and gCC MD were observed in the hydrocephalus group and were similar to those in the control group (p = 0.107, p = 0.702, and p = 0.169, respectively). There were no correlations identified between FOHR and MDs at either time point.

CONCLUSIONS

The utility of fast brain MRI can be extended beyond anatomical assessments to obtain dMRI measures. A reduction in PLIC and gCC MD to levels similar to those of controls was observed within 14 months following shunt surgery for hydrocephalus in PHH and CH infants. Further studies are required to assess the role of fast brain dMRI for assessing clinical outcomes in pediatric hydrocephalus patients.

Altered neonatal white and gray matter microstructure is associated with neurodevelopmental impairments in very preterm infants with high-grade brain injury

BACKGROUND

This study examines relationships between neonatal white and gray matter microstructure and neurodevelopment in very preterm (VPT) infants (≤30 weeks gestation) with high-grade brain injury (BI).

METHODS

Term-equivalent diffusion tensor magnetic resonance imaging data were obtained in 32 VPT infants with high-grade BI spanning grade III/IV intraventricular hemorrhage, post-hemorrhagic hydrocephalus (PHH), and cystic periventricular leukomalacia (BI group); 69 VPT infants without high-grade injury (VPT group); and 55 term-born infants. The Bayley-III assessed neurodevelopmental outcomes at age 2 years.

RESULTS

BI infants had lower fractional anisotropy (FA) in the posterior limb of the internal capsule (PLIC), cingulum, and corpus callosum, and higher mean diffusivity (MD) in the optic radiations and cingulum than VPT infants. PHH was associated with higher MD in the optic radiations and left PLIC, and higher FA in the right caudate. For BI infants, higher MD in the right optic radiation and lower FA in the right cingulum, PLIC, and corpus callosum were related to motor impairments.

CONCLUSIONS

BI infants demonstrated altered white and gray matter microstructure in regions affected by injury in a manner dependent upon injury type. PHH infants demonstrated the greatest impairments. Aberrant white matter microstructure was related to motor impairment in BI infants.

Diffusion tensor imaging and ventricle volume quantification in patients with chronic shunt-treated hydrocephalus: a matched case-control study

OBJECTIVEThe object of this study was to use diffusion tensor imaging (DTI) and tract-based spatial statistics (TBSS) to characterize the long-term effects of hydrocephalus and shunting on white matter integrity and to investigate the relationship of ventricular size and alterations in white matter integrity with headache and quality-of-life outcome measures.METHODSPatients with shunt-treated hydrocephalus and age- and sex-matched healthy controls were recruited into the study and underwent anatomical and DTI imaging on a 3-T MRI scanner. All patients were clinically stable, had undergone CSF shunt placement before 2 years of age, and had a documented history of complaints of headaches. Outcome was scored based on the Headache Disability Inventory and the Hydrocephalus Outcome Questionnaire. Fractional anisotropy (FA) and other DTI-based measures (axial, radial, and mean diffusivity; AD, RD, and MD, respectively) were extracted in the corpus callosum and internal capsule with manual region-of-interest delineation and in other regions with TBSS. Paired t-tests, corrected with a 5% false discovery rate, were used to identify regions with significant differences between patients and controls. Within the patient group, linear regression models were used to investigate the relationship between FA or ventricular volume and outcome, as well as the effect of shunt-related covariates.RESULTSTwenty-one hydrocephalus patients and 21 matched controls completed the study, and their data were used in the final analysis. The authors found significantly lower FA for patients than for controls in 20 of the 48 regions, mostly posterior white matter structures, in periventricular as well as more distal tracts. Of these 20 regions, 17 demonstrated increased RD, while only 5 showed increased MD and 3 showed decreased AD. No areas of increased FA were observed. Higher FA in specific periventricular white matter tracts, tending toward FA in controls, was associated with increased ventricular size, as well as improved clinical outcome.CONCLUSIONSThe study shows that TBSS-based DTI is a sensitive technique for elucidating changes in white matter structures due to hydrocephalus and chronic CSF shunting and provides preliminary evidence that DTI may be a valuable tool for tailoring shunt procedures to monitor ventricular size following shunting and achieve optimal outcome, as well as for guiding the development of alternate therapies for hydrocephalus.

Preterm neuroimaging and neurodevelopmental outcome: a focus on intraventricular hemorrhage, post-hemorrhagic hydrocephalus, and associated brain injury

Intraventricular hemorrhage in the setting of prematurity remains the most common cause of acquired hydrocephalus. Neonates with progressive post-hemorrhagic hydrocephalus are at risk for adverse neurodevelopmental outcomes. The goal of this review is to describe the distinct and often overlapping types of brain injury in the preterm neonate, with a focus on neonatal hydrocephalus, and to connect injury on imaging to neurodevelopmental outcome risk. Head ultrasound and magnetic resonance imaging findings are described separately. The current state of the literature is imprecise and we end the review with recommendations for future radiologic and neurodevelopmental research.

Extended Combined Neonatal Treatment With Erythropoietin Plus Melatonin Prevents Posthemorrhagic Hydrocephalus of Prematurity in Rats

Posthemorrhagic hydrocephalus of prematurity (PHHP) remains a global challenge. Early preterm infants (<32 weeks gestation), particularly those exposed to chorioamnionitis (CAM), are prone to intraventricular hemorrhage (IVH) and PHHP. We established an age-appropriate, preclinical model of PHHP with progressive macrocephaly and ventriculomegaly to test whether non-surgical neonatal treatment could modulate PHHP. We combined prenatal CAM and postnatal day 1 (P1, equivalent to 30 weeks human gestation) IVH in rats, and administered systemic erythropoietin (EPO) plus melatonin (MLT), or vehicle, from P2 to P10. CAM-IVH rats developed progressive macrocephaly through P21. Macrocephaly was accompanied by ventriculomegaly at P5 (histology), and P21 (ex vivo MRI). CAM-IVH rats showed impaired performance of cliff aversion, a neonatal neurodevelopmental test. Neonatal EPO+MLT treatment prevented macrocephaly and cliff aversion impairment, and significantly reduced ventriculomegaly. EPO+MLT treatment prevented matted or missing ependymal motile cilia observed in vehicle-treated CAM-IVH rats. EPO+MLT treatment also normalized ependymal yes-associated protein (YAP) mRNA levels, and reduced ependymal GFAP-immunolabeling. Vehicle-treated CAM-IVH rats exhibited loss of microstructural integrity on diffusion tensor imaging, which was normalized in EPO+MLT-treated CAM-IVH rats. In summary, combined prenatal systemic inflammation plus early postnatal IVH caused progressive macrocephaly, ventriculomegaly and delayed development of cliff aversion reminiscent of PHHP. Neonatal systemic EPO+MLT treatment prevented multiple hallmarks of PHHP, consistent with a clinically viable, non-surgical treatment strategy.

Congenital aqueduct stenosis: Progressive brain findings in utero to birth in the presence of severe hydrocephalus

PURPOSE

To evaluate the effects of progressive hydrocephalus on the developing brain in a cohort of fetuses diagnosed with congenital aqueduct stenosis by comparing prenatal magnetic resonance imaging and postnatal imaging.

METHODS

This IRB approved single center retrospective review of prenatally diagnosed children with congenital aqueduct stenosis interrogated changes in the brain between prenatal and postnatal imaging and analyzed statistics using SAS software package version 9.3.

RESULTS

Thirty fetuses imaged at a mean gestational age of 26 weeks had aqueduct obstruction confirmed by postnatal imaging. Progressive hydrocephalus required shunting in all but one patient (97%). Those patients with increasing hydrocephalus showed increase in ventricular rupture (60%), loss of septal leaflets (47%), and reduction in white matter and corpus callosum volume (43%). Cerebellar ectopia developed in 27% with 6% meeting the criteria for Chiari I malformation.

CONCLUSION

Hydrocephalus in the fetus results in enlarging ventricular rupture, loss of the septum pellucidum leaflets, volume reduction of brain parenchyma including corpus callosum, and risk for Chiari I anomaly. Given advances in fetal surgery and imaging in the last 3 decades, there may be cause to revisit the idea of in utero cerebral spinal fluid diversion as a means to potentially ameliorate progressive loss of the developing brain.

Left hemisphere structural connectivity abnormality in pediatric hydrocephalus patients following surgery

Neuroimaging research in surgically treated pediatric hydrocephalus patients remains challenging due to the artifact caused by programmable shunt. Our previous study has demonstrated significant alterations in the whole brain white matter structural connectivity based on diffusion tensor imaging (DTI) and graph theoretical analysis in children with hydrocephalus prior to surgery or in surgically treated children without programmable shunts. This study seeks to investigate the impact of brain injury on the topological features in the left hemisphere, contratelateral to the shunt placement, which will avoid the influence of shunt artifacts and makes further group comparisons feasible for children with programmable shunt valves. Three groups of children (34 in the control group, 12 in the 3-month post-surgery group, and 24 in the 12-month post-surgery group, age between 1 and 18 years) were included in the study. The structural connectivity data processing and analysis were performed based on DTI and graph theoretical analysis. Specific procedures were revised to include only left brain imaging data in normalization, parcellation, and fiber counting from DTI tractography. Our results showed that, when compared to controls, children with hydrocephalus in both the 3-month and 12-month post-surgery groups had significantly lower normalized clustering coefficient, lower small-worldness, and higher global efficiency (all p < 0.05, corrected). At a regional level, both patient groups showed significant alteration in one or more regional connectivity measures in a series of brain regions in the left hemisphere (8 and 10 regions in the 3-month post-surgery and the 12-month post-surgery group, respectively, all p < 0.05, corrected). No significant correlation was found between any of the global or regional measures and the contemporaneous neuropsychological outcomes [the General Adaptive Composite (GAC) from the Adaptive Behavior Assessment System, Second Edition (ABAS-II)]. However, one global network measure (global efficiency) and two regional network measures in the insula (local efficiency and between centrality) tested at 3-month post-surgery were found to correlate with GAC score tested at 12-month post-surgery with statistical significance (all p < 0.05, corrected). Our data showed that the structural connectivity analysis based on DTI and graph theory was sensitive in detecting both global and regional network abnormality when the analysis was conducted in the left hemisphere only. This approach provides a new avenue enabling the application of advanced neuroimaging analysis methods in quantifying brain damage in children with hydrocephalus surgically treated with programmable shunts.

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We studied the structural connectivity of left hemisphere brain network in children with hydrocephalus post-surgery

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Children with hydrocephalus post-surgery had significantly abnormal structural connectivity in the left hemisphere based on graph analysis

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Significant correlation was found between graph measures at 3-months post-surgery and developmental outcome at 12-month post-surgery