Dilatation of Virchow-Robin spaces in children hospitalized at pediatric neurology department

Glymphatic Imaging in Pediatrics

The glymphatic system, which facilitates cerebrospinal fluid (CSF) flow through the brain parenchyma, is important for brain development and waste clearance. Advances in imaging techniques, particularly magnetic resonance imaging, have make it possible to evaluate glymphatic structures and functions in vivo. Recently, several studies have focused on the development and alterations of the glymphatic system in pediatric disorders. This review discusses the development of the glymphatic system, advances of imaging techniques and their applications in pediatric disorders. First, the results of the reviewed studies indicate that the development of the glymphatic system is a long-lasting process that continues into adulthood. Second, there is a need for improved glymphatic imaging techniques that are non-invasive and fast to improve suitability for pediatric applications, as some of existing methods use contrast injection and are susceptible to motion artifacts from long scanning times. Several novel techniques are potentially feasible for pediatric patients and may be used in the future. Third, the glymphatic dysfunction is associated with a large number of pediatric disorders, although only a few have recently been investigated. In conclusion, research on the pediatric glymphatic system remains an emerging field. The preliminary applications of glymphatic imaging techniques have provided unique insight into the pathological mechanism of pediatric diseases, but mainly limited in visualization of enlarged perivascular spaces and morphological measurements on CSF volumes. More in-depth studies on glymphatic functions are required to improve our understanding of the mechanisms underlying brain development and pediatric diseases. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 3.

Knobloch syndrome - a rare collagenopathy, revealing peripheral avascular retina

INTRODUCTION

Pediatric rhegmatogenous retinal detachments, especially those presenting at birth or soon afterward, have a high likelihood of syndromic associations that can be confirmed by genetic testing.

MATERIALS AND METHODS

A 5-month-old child was found to have high myopia in the right eye (RE) with highly tessellated fundus, opalescent vitreous, and peripheral thinning. Left eye had a shallow retinal detachment for which he underwent belt buckling. The baby had an occipital skin tag. A provisional diagnosis of Stickler syndrome was made.

RESULTS

On 1-month follow-up, left eye retina was attached and 360° laser barrage was done. Fluorescein angiography was done which revealed peripheral avascular retina in both eyes. MRI and genetic testing were suggestive of syndromic association. Genetic testing revealed pathogenic mutation in COL 18A1 suggestive of Knobloch syndrome in the baby, and both parents were found to be carriers of the same mutation. However, brain MRI showed features not pathognomonic of Knobloch syndrome.

CONCLUSION

Although Knobloch syndrome is associated with vitreoretinal degeneration and high risk of retinal detachment, there seems to be no recommendation for prophylaxis in the other eye and therefore we preferred to observe the RE closely. A unique feature noted in our case was the peripheral avascular zone (PAZ). The PAZ could be contributed by multiple factors such as high myopia, or due to endostatin deficiency (which is a derivative of collagen XVIII) or an underlying WNT signalling abnormality.

Dedicated neuroimaging analysis in children with primary headaches: prevalence of lesions and a comparison between patients with and without migraines

BACKGROUND

This study evaluated the prevalence and types of intracranial lesions through dedicated imaging analysis of primary headaches in children and compared them between patients with and without migraine.

METHODS

This study included 190 children diagnosed with primary headache who underwent neuroimaging, including brain computed tomography (CT), CT angiography (CTA), and brain magnetic resonance imaging (MRI). All patients with primary headaches was divided into two groups, namely, the migraine and non-migraine groups, on the basis of data from electronic medical records. Clinical characteristics and imaging findings were evaluated and compared between the two groups.

RESULTS

Patients with migraine were old and had a longer period from symptom onset to diagnosis. CT was normal in 71 of 95 patients, whereas 7 of 29 patients who underwent CTA had vascular lesions; the migraine group (n = 6/20, [30%]) had higher incidence of vascular lesions than the non-migraine group (n = 1/9, [11.1%]); however, there was no statistically significant difference (p = 0.382). Furthermore, 57.5% (61/106) of children showed normal brain MRI. The most common brain MRI finding was dilated perivascular space (n = 18, [16.8%]). Most perivascular spaces were located in the basal ganglia (n = 72, [75.8%]) and were in linear patterns (n = 58, [63.0%]). There was no statistically significant difference between the two groups.

CONCLUSION

A low prevalence of significant abnormalities was found in children with primary headaches. Dilated perivascular space was the most common finding in both groups on MRI. CTA showed more vascular lesions in the migraine group than in the non-migraine group. Therefore, further evaluations are needed to reveal the relationship between vascular lesions or dilated perivascular space and pediatric primary headaches.

Exploring Variances of White Matter Integrity and the Glymphatic System in Simple Febrile Seizures and Epilepsy

Background: Simple febrile seizures (SFS) and epilepsy are common seizures in childhood. However, the mechanism underlying SFS is uncertain, and the presence of obvious variances in white matter (WM) integrity and glymphatic function between SFS and epilepsy remain unclear. Therefore, this study aimed to investigate the differences in WM integrity and glymphatic function between SFS and epilepsy.

Material and Methods: We retrospectively included 26 children with SFS, 33 children with epilepsy, and 28 controls aged 6–60 months who underwent magnetic resonance imaging (MRI). Tract-based spatial statistics (TBSS) were used to compare the diffusion tensor imaging (DTI) metrics of WM among the above-mentioned groups. T2-weighted imaging (T2WI) was used to segment the visible Virchow-Robin space (VRS) through a custom-designed automated method. VRS counts and volume were quantified and compared among the SFS, epilepsy, and control groups. Correlations of the VRS metrics and seizure duration and VRS metrics and the time interval between seizure onset and MRI scan were also investigated.

Results: In comparison with controls, children with SFS showed no significant changes in fractional anisotropy (FA), axial diffusivity (AD), or radial diffusivity (RD) in the WM (P > 0.05). Decreased FA, unchanged AD, and increased RD were observed in the epilepsy group in comparison with the SFS and control groups (P < 0.05). Meanwhile, VRS counts were higher in the SFS and epilepsy groups than in the control group (VRS_SFS, 442.42 ± 74.58, VRS_epilepsy, 629.94 ± 106.55, VRS_control, 354.14 ± 106.58; P < 0.001), and similar results were found for VRS volume (VRS_SFS, 6,228.18 ± 570.74 mm³, VRS_epilepsy, 9,684.84 ± 7,292.66mm³, VRS_control, 4,007.22 ± 118.86 mm³; P < 0.001). However, VRS metrics were lower in the SFS group than in the epilepsy group (P < 0.001). In both SFS and epilepsy, VRS metrics positively correlated with seizure duration and negatively correlated with the course after seizure onset.

Conclusion: SFS may not be associated with WM microstructural disruption; however, epilepsy is related to WM alterations. Seizures are associated with glymphatic dysfunction in either SFS or epilepsy.

Imaging for central nervous system (CNS) interstitial fluidopathy: disorders with impaired interstitial fluid dynamics

After the introduction of the glymphatic system hypothesis, an increasing number of studies on cerebrospinal fluid and interstitial fluid dynamics within the brain have been investigated and reported. A series of diseases are known which develop due to abnormality of the glymphatic system including Alzheimer's disease, traumatic brain injury, stroke, or other disorders. These diseases or disorders share the characteristics of the glymphatic system dysfunction or other mechanisms related to the interstitial fluid dynamics. In this review article, we propose "Central Nervous System (CNS) Interstitial Fluidopathy" as a new concept encompassing diseases whose pathologies are majorly associated with abnormal interstitial fluid dynamics. Categorizing these diseases or disorders as "CNS interstitial fluidopathies," will promote the understanding of their mechanisms and the development of potential imaging methods for the evaluation of the disease as well as clinical methods for disease treatment or prevention. In other words, having a viewpoint of the dynamics of interstitial fluid appears relevant for understanding CNS diseases or disorders, and it would be possible to develop novel common treatment methods or medications for "CNS interstitial fluidopathies."

Quantification of visible Virchow-Robin spaces for detecting the functional status of the glymphatic system in children with newly diagnosed idiopathic generalized epilepsy

PURPOSE

The cerebral glymphatic system, particularly the Virchow-Robin Spaces (VRS), plays an important role in waste clearance from the brain. Idiopathic generalized epilepsy (IGE) is a common epilepsy type associated with blood-brain-barrier dysfunction, abnormal exchange of cerebrospinal fluid and interstitial fluid. These disorders may be reflected in the glymphatic system. Therefore, this study investigated the relationships between visible VRS on MRI and seizures, to detect changes in glymphatic function.

METHODS

We retrospectively included 32 children with newly diagnosed IGE and 30 controls aged 3-13 years. Visible VRS were identified using a custom-designed automated method. VRS counts and volume were quantified and compared between children with IGE and controls. Meanwhile, Correlations of VRS counts and volume with seizure duration and course after seizure onset were respectively explored via Spearman's coefficient (r).

RESULTS

In this study, visible VRS counts were higher in IGE than control group (VRS_{_epilepsy}, 234.34 ± 113.88 vs. VRS_{_control}, 111.83 ± 52.46; P < 0.001), as similar results were found in VRS volume (VRS_{_epilepsy}, 1377.47 ± 778.79 mm³ vs. VRS_{_control}, 795.153 ± 452.49 mm³; P = 0.001). Visible VRS counts and volume positively correlated with seizure duration (r_{_counts} = 0.638, r_{_volume} = 0.639; P < 0.001) and gradually decreased with time after seizure onset (r_{_counts} = -0.559, r__volume = -0.558; P < 0.001).

CONCLUSION

Epileptic seizures can induce changes in VRS counts and volume, which were associated with seizure duration and post-onset course. Quantitative metrics of VRS visible on MRI might be potential biomarkers for monitoring glymphatic function.

Perivascular spaces and headache: A population-based imaging study (HUNT-MRI)

Background

In four previous clinic-based MRI studies headache sufferers (in particular migraineurs) had more perivascular spaces (PVS) than individuals who were headache-free.

Methods

The present study was part of a large longitudinal, epidemiological study (Nord-Trøndelag Health Survey (HUNT)). The 1006 participants, age 50–65 years at inclusion, had participated in all previous HUNT surveys (1–3), and been randomly selected to a population-based imaging study of the head (HUNT-MRI, 2007–2009). The number of visible PVS in the basal ganglia (BG) and hemispheric white matter (HWM) was compared in headache sufferers (migraine with and without aura, non-migrainous headache) and people who were headache-free.

Results

The results showed in general small differences between headache sufferers and headache-free participants. In the cross-sectional analysis migraineurs without aura had fewer PVS than headache-free individuals in BG (OR = 0.84, 95% CI = 0.76--0.94, p value = 0.003) and in BG and HWM together (OR = 0.97, 95% CI = 0.95-1.00, p value = 0.046). No difference between long-term headache sufferers and long-term headache-free individuals with regard to number of PVS was found.

Discussion

In contrast to previous studies, the present large, blinded, population-based study showed no increase in number of dilated PVS among headache sufferers. Fewer PVS among those with migraine without aura may be a spurious finding.