Randomized controlled double-blind trial of methylprednisolone versus placebo in patients with post-COVID-19 syndrome and cognitive deficits: study protocol of the post-corona-virus immune treatment (PoCoVIT) trial

INTRODUCTION

Post-COVID-19 Syndrome (PCS) includes neurological manifestations, especially fatigue and cognitive deficits. Immune dysregulation, autoimmunity, endothelial dysfunction, viral persistence, and viral reactivation are discussed as potential pathophysiological mechanisms. The post-corona-virus immune treatment (PoCoVIT) trial is a phase 2a randomized, controlled, double-blind trial designed to evaluate the effect of methylprednisolone versus placebo on cognitive impairment in PCS. This trial is designed based on the hypothesised autoimmunological pathogenesis and positive aberrations, employing a series of off-label applications.

METHODS

Recruitment criteria include a diagnosis of PCS, a minimum age of 18 years and self-reported cognitive deficits at screening. A total of 418 participants will be randomly assigned to either verum or placebo intervention in the first phase of the trial. The trial will consist of a first trial phase intervention with methylprednisolone versus placebo for six weeks, followed by a six-week treatment interruption period. Subsequently, an open second phase will offer methylprednisolone to all participants for six weeks. Outpatient follow-up visits will take place two weeks after each trial medication cessation. The third and final follow-up, at week 52, will be conducted through a telephone interview. The primary outcome measures an intra-patient change of 15 or more points in the memory satisfaction subscale of the Multifactorial Memory Questionnaire (MMQ) from baseline to follow-up 1 (week 8). Key secondary outcomes include long-term intra-patient changes in memory satisfaction from baseline to follow-up 2 (week 20), changes in other MMQ subscales (follow-up 1 and 2), and changes in neuropsychological and cognitive scores, along with assessments through questionnaires focusing on quality of life, fatigue, and mood over the same periods. Exploratory outcomes involve molecular biomarkers variations in serum and cerebrospinal fluid, as well as structural and functional brain magnetic resonance imaging (MRI) parameters changes related to cognition.

PERSPECTIVE

This trial aims to contribute novel evidence for treating patients with PCS, with a primary focus on those manifesting cognitive deficits. By doing so, it may enhance comprehension of the underlying pathophysiological mechanisms, thereby facilitating biomarker research to advance our understanding and treatment of patients with PCS.

IA-PACS-CFS: a double-blinded, randomized, sham-controlled, exploratory trial of immunoadsorption in patients with chronic fatigue syndrome (CFS) including patients with post-acute COVID-19 CFS (PACS-CFS)

BACKGROUND

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a severely debilitating condition which markedly restricts activity and function of affected people. Since the beginning of the COVID-19 pandemic ME/CFS related to post-acute COVID-19 syndrome (PACS) can be diagnosed in a subset of patients presenting with persistent fatigue 6 months after a mostly mild SARS-CoV-2 infection by fulfillment of the Canadian Consensus Criteria (CCC 2003). Induction of autoimmunity after viral infection is a mechanism under intensive investigation. In patients with ME/CFS, autoantibodies against thyreoperoxidase (TPO), beta-adrenergic receptors (ß2AR), and muscarinic acetylcholine receptors (MAR) are frequently found, and there is evidence for effectiveness of immunomodulation with B cell depleting therapy, cyclophosphamide, or intravenous immunoglobulins (IVIG). Preliminary studies on the treatment of ME/CFS patients with immunoadsorption (IA), an apheresis that removes antibodies from plasma, suggest clinical improvement. However, evidence from placebo-controlled trials is currently missing.

METHODS

In this double-blinded, randomized, sham-controlled, exploratory trial the therapeutic effect of five cycles of IA every other day in patients with ME/CFS, including patients with post-acute COVID-19 chronic fatigue syndrome (PACS-CFS), will be evaluated using the validated Chalder Fatigue Scale, a patient-reported outcome measurement. A total of 66 patients will be randomized at a 2:1 ratio: 44 patients will receive IA (active treatment group) and 22 patients will receive a sham apheresis (control group). Moreover, safety, tolerability, and the effect of IA on patient-reported outcome parameters, biomarker-related objectives, cognitive outcome measurements, and physical parameters will be assessed. Patients will be hospitalized at the clinical site from day 1 to day 10 to receive five IA treatments and medical visits. Four follow-up visits (including two visits at site and two visits via telephone call) at month 1 (day 30), 2 (day 60), 4 (day 120), and 6 (day 180; EOS, end of study visit) will take place.

DISCUSSION

Although ME/CFS including PACS-CFS causes an immense individual, social, and economic burden, we lack efficient therapeutic options. The present study aims to investigate the efficacy of immunoadsorption and to contribute to the etiological understanding and establishment of diagnostic tools for ME/CFS.

TRIAL REGISTRATION

Registration Number: NCT05710770 . Registered on 02 February 2023.

Early, low-dose hydrocortisone and near-term brain connectivity in extremely preterm infants

BACKGROUND

Postnatal steroids are used to prevent bronchopulmonary dysplasia in extremely preterm infants but may have adverse effects on brain development. We assessed connectivity metrics of major cerebral and cerebellar white matter pathways at near-term gestational age among infants who did or did not receive a standardized regimen of hydrocortisone during the first 10 days of life.

METHODS

Retrospective cohort study.

PARTICIPANTS

Infants born <28 weeks: Protocol group (n = 33) received at least 50% and not more than 150% of an intended standard dose of 0.5 mg/kg hydrocortisone twice daily for 7 days, then 0.5 mg/kg per day for 3 days; Non-Protocol group (n = 22), did not receive protocol hydrocortisone or completed <50% of the protocol dose. We assessed group differences in near-term diffusion MRI mean fractional anisotropy (FA) and mean diffusivity (MD) across the corticospinal tract, inferior longitudinal fasciculus, corpus callosum and superior cerebellar peduncle.

RESULTS

Groups were comparable in gestational age, post-menstrual age at scan, medical complications, bronchopulmonary dysplasia, and necrotizing enterocolitis. No significant large effect group differences were identified in mean FA or MD in any cerebral or cerebellar tract.

CONCLUSION(S)

Low dose, early, postnatal hydrocortisone was not associated with significant differences in white matter tract microstructure at near-term gestational age.

IMPACT

This study compared brain microstructural connectivity as a primary outcome among extremely preterm infants who did or did not receive early postnatal hydrocortisone. Low dose hydrocortisone in the first 10 days of life was not associated with significant differences in white matter microstructure in major cerebral and cerebellar pathways. Hydrocortisone did not have a significant effect on early brain white matter circuits.

Associations of behavioral problems with white matter circuits connecting to the frontal lobes in school-aged children born at term and preterm

Introduction

This study investigated whether behavioral problems in children were associated with fractional anisotropy (FA) of white matter tracts connecting from other brain regions to right and left frontal lobes. We considered internalizing and externalizing behavioral problems separately and contrasted patterns of associations in children born at term and very preterm.

Methods

Parents completed the Child Behavior Checklist/6-18 questionnaire to quantify behavioral problems when their children were age 8 years (N=36 FT and 37 PT). Diffusion magnetic resonance scans were collected at the same age and analyzed using probabilistic tractography. We used multiple linear regression to investigate the strength of association between age-adjusted T-scores of internalizing and externalizing problems and mean fractional anisotropy (mean-FA) of right and left uncinate, arcuate, and anterior thalamic radiations, controlling for birth group and sex.

Results

Regression models predicting internalizing T-scores from mean-FA found significant group-by-tract interactions for the left and right arcuate and right uncinate. Internalizing scores were negatively associated with mean-FA of left and right arcuate only in children born at term (pleft AF =0.01, pright AF =0.01). Regression models predicting externalizing T-scores from mean-FA found significant group-by-tract interactions for the left arcuate and right uncinate. Externalizing scores were negatively associated with mean-FA of right uncinate in children born at term (pright UF =0.01) and positively associated in children born preterm (pright UF preterm =0.01). Other models were not significant.

Conclusions

In this sample of children with scores for behavioral problems across the full range, internalizing and externalizing behavioral problems were negatively associated with mean-FA of white matter tracts connecting to frontal lobes in children born at term; externalizing behavioral problems were positively associated with mean-FA of the right uncinate in children born preterm. The different associations by birth group suggest that the neurobiology of behavioral problems differs in the two birth groups.

Fighting Post-COVID and ME/CFS - development of curative therapies

The sequela of COVID-19 include a broad spectrum of symptoms that fall under the umbrella term post-COVID-19 condition or syndrome (PCS). Immune dysregulation, autoimmunity, endothelial dysfunction, viral persistence, and viral reactivation have been identified as potential mechanisms. However, there is heterogeneity in expression of biomarkers, and it is unknown yet whether these distinguish different clinical subgroups of PCS. There is an overlap of symptoms and pathomechanisms of PCS with postinfectious myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). No curative therapies are available for ME/CFS or PCS. The mechanisms identified so far provide targets for therapeutic interventions. To accelerate the development of therapies, we propose evaluating drugs targeting different mechanisms in clinical trial networks using harmonized diagnostic and outcome criteria and subgrouping patients based on a thorough clinical profiling including a comprehensive diagnostic and biomarker phenotyping.

Associations of Behavioral Problems and White Matter Properties of the Cerebellar Peduncles in Boys and Girls Born Full Term and Preterm

Accumulating evidence suggests that the role of cerebellum includes regulation of behaviors; cerebellar impairment may lead to behavioral problems. Behavioral problems differ by sex: internalizing problems are more common in girls, externalizing problems in boys. Behavioral problems are also elevated in children born preterm (PT) compared to children born full term (FT). The current study examined internalizing and externalizing problems in 8-year-old children in relation to sex, birth-group, fractional anisotropy (FA) of the three cerebellar peduncles (superior, middle, and inferior), and interactions among these predictor variables. Participants (N = 78) were 44 boys (28 PT) and 34 girls (15 PT). We assessed behavioral problems via standardized parent reports and FA of the cerebellar peduncles using deterministic tractography. Internalizing problems were higher in children born PT compared to children born FT (p = .032); the interaction of sex and birth-group was significant (p = .044). When considering the contribution of the mean-tract FA of cerebellar peduncles to behavioral problems, there was a significant interaction of sex and mean-tract FA of the inferior cerebellar peduncle (ICP) with internalizing problems; the slope was negative in girls (p = .020) but not in boys. In boys, internalizing problems were only associated with mean-tract FA ICP in those born preterm (p = .010). We found no other significant associations contributing to internalizing or externalizing problems. Thus, we found sexual dimorphism and birth-group differences in the association of white matter metrics of the ICP and internalizing problems in school-aged children. The findings inform theories of the origins of internalizing behavioral problems in middle childhood and may suggest approaches to treatment at school age.

Spatiotemporal changes in along-tract profilometry of cerebellar peduncles in cerebellar mutism syndrome

Cerebellar mutism syndrome, characterised by mutism, emotional lability and cerebellar motor signs, occurs in up to 39% of children following resection of medulloblastoma, the most common malignant posterior fossa tumour of childhood. Its pathophysiology remains unclear, but prior studies have implicated damage to the superior cerebellar peduncles. In this study, the objective was to conduct high-resolution spatial profilometry of the cerebellar peduncles and identify anatomic biomarkers of cerebellar mutism syndrome. In this retrospective study, twenty-eight children with medulloblastoma (mean age 8.8 ± 3.8 years) underwent diffusion MRI at four timepoints over one year. Forty-nine healthy children (9.0 ± 4.2 years), scanned at a single timepoint, served as age- and sex-matched controls. Automated Fibre Quantification was used to segment cerebellar peduncles and compute fractional anisotropy (FA) at 30 nodes along each tract. Thirteen patients developed cerebellar mutism syndrome. FA was significantly lower in the distal third of the left superior cerebellar peduncle pre-operatively in all patients compared to controls (FA in proximal third 0.228, middle and distal thirds 0.270, p = 0.01, Cohen's d = 0.927). Pre-operative differences in FA did not predict cerebellar mutism syndrome. However, post-operative reductions in FA were highly specific to the distal left superior cerebellar peduncle, and were most pronounced in children with cerebellar mutism syndrome compared to those without at the 1-4 month follow up (0.325 vs 0.512, p = 0.042, d = 1.36) and at the 1-year follow up (0.342, vs 0.484, p = 0.038, d = 1.12). High spatial resolution cerebellar profilometry indicated a site-specific alteration of the distal segment of the superior cerebellar peduncle seen in cerebellar mutism syndrome which may have important surgical implications in the treatment of these devastating tumours of childhood.

Spatiotemporal changes in along-tract profilometry of cerebellar peduncles in cerebellar mutism syndrome

Aims

Cerebellar mutism syndrome occurs in 25% of children following resection of posterior fossa tumours. Characterised by mutism, emotional lability and cerebellar motor signs, the syndrome is usually reversible over weeks to months. Its pathophysiology remains unclear, but evidence from diffusion MRI studies has implicated damage to the superior cerebellar peduncles in the development of this condition. The objective of this study was to describe the application of automated tractography of the cerebellar peduncles to provide a high-resolution spatiotemporal profile of diffusion MRI changes in cerebellar mutism syndrome.

Method

A retrospective case-control study was performed at Lucille Packard Children’s Hospital, Stanford University. Thirty children with midline medulloblastoma (mean age ± standard deviation 8.8 ± 3.8 years) underwent volumetric T1-weighted and diffusion MRI at four timepoints over one year. Forty-nine healthy children (9.0 ± 4.2 years), scanned at a single timepoint, were included as age- and sex-matched controls. Cerebellar mutism syndrome status was determined by contemporaneous casenote review. Automated Fibre Quantification was used to segment each subject’s cerebellar peduncles (Figure 1), and fractional anisotropy was computed at 30 nodes along each tract. A non-parametric permutation-based method was used to generate a critical cluster size and p-value for by-node ANOVA group comparisons. Z-scores for patients’ fractional anisotropy at each node were calculated based on values from controls’ corresponding nodes; these were analysed using mixed ANOVA with post-hoc false discovery rate-corrected pairwise t-tests.

Results

13 patients developed cerebellar mutism syndrome. Automated fibre segmentation successfully identified the cerebellar peduncles in the majority of participants, but was more robust at follow-up timepoints (78.7% vs. 44.7% pre-operatively). Fractional anisotropy was significantly lower in the distal regions of the left superior cerebellar peduncle pre-operatively (p=0.0137) in patients compared to controls, although patients could not be distinguished pre-operatively with respect to cerebellar mutism syndrome status (Figure 2). Post-operative reductions in fractional anisotropy in children with cerebellar mutism syndrome were highly specific to the distal left superior cerebellar peduncle, and were most pronounced at follow-up timepoints (p=0.006; Figure 3). There were no significant differences in other cerebellar peduncles, either in along-tract fractional anisotropy or Z-scores, with respect to cerebellar mutism syndrome status.

Conclusion

A novel application of an automated tool to extract diffusion MRI data along the length of the cerebellar peduncles is described in a longitudinal retrospective cohort of paediatric medulloblastoma. Changes in fractional anisotropy in the cerebellar peduncles following tumour resection are described in a heretofore unprecedented level of spatiotemporal detail. In particular, children with post-operative cerebellar mutism syndrome show changes in the distal regions of the left superior cerebellar peduncle, and these changes persist up to a year post-operatively. These findings will have direct clinical implications for neurosurgeons performing resection of midline paediatric posterior fossa tumours.

The Effect of an Abdominal Binder on Postoperative Pain after Laparoscopic Incisional Hernia Repair-A Multicenter, Randomized Pilot Trial (ABIHR-I) of the Intraperitoneal Onlay-Mesh Technique

BACKGROUND

Incisional hernias with apertures measuring less than 7 cm can generally be treated adequately with the laparoscopic intraperitoneal onlay-mesh (IPOM) technique. The wearing of an abdominal binder after surgery is often recommended in order to promote wound healing and prevent recurrent herniation. We carried out a multicenter, randomized pilot trial to evaluate the utility of abdominal binders.

METHODS

The trial was conducted from May 2019 to December 2020. Persons treated for an incisional hernia with a laparoscopic IPOM procedure were included in the trial and randomized preoperatively into two equal-sized groups: the patients in one group wore an abdominal binder during the daytime for 14 days after surgery, while those in the other group wore no binder. The primary endpoint was pain at rest on postoperative days 1, 2, and 14, as measured on a visual analog scale. The secondary endpoints were overall subjective wellbeing, the rates of wound infection and recurrence, the complication rate, mobility, and the rate and size of postoperative wound seroma formation (on postoperative days 1, 2, and 14).

RESULTS

40 patients were included in the pilot trial. Three had to be excluded because of intraoperative conversion to an open surgical technique. The binder and no-binder groups (18 and 19 patients, respectively) did not differ in their biometric and perioperative data to any statistically significant extent. The patients in the binder group had significantly less postoperative pain (F [dfn, dfd] 4.44, 95% confidence interval [1; 35], p = 0.042).The patients in the binder group also had better overall subjective well-being and a higher rate of postoperative wound seroma formation than those in the no-binder group, but these differences did not reach statistical significance. The patients in the binder group had less limitation of mobility than those in the other group; this difference did not reach statistical significance, either.

CONCLUSION

A postoperatively worn abdominal binder may reduce pain after incisional hernia repair with the IPOM technique. The postoperative use of analgesic medication was not measured.

Effects of Age on White Matter Microstructure in Children With Neurofibromatosis Type 1

Children with neurofibromatosis type 1 (NF1) often report cognitive challenges, though the etiology of such remains an area of active investigation. With the advent of treatments that may affect white matter microstructure, understanding the effects of age on white matter aberrancies in NF1 becomes crucial in determining the timing of such therapeutic interventions. A cross-sectional study was performed with diffusion tensor imaging from 18 NF1 children and 26 age-matched controls. Fractional anisotropy was determined by region of interest analyses for both groups over the corpus callosum, cingulate, and bilateral frontal and temporal white matter regions. Two-way analyses of variance were done with both ages combined and age-stratified into early childhood, middle childhood, and adolescence. Significant differences in fractional anisotropy between NF1 and controls were seen in the corpus callosum and frontal white matter regions when ages were combined. When stratified by age, we found that this difference was largely driven by the early childhood (1-5.9 years) and middle childhood (6-11.9 years) age groups, whereas no significant differences were appreciable in the adolescence age group (12-18 years). This study demonstrates age-related effects on white matter microstructure disorganization in NF1, suggesting that the appropriate timing of therapeutic intervention may be in early childhood.

Associations of Reading Efficiency with White Matter Properties of the Cerebellar Peduncles in Children

Reading in children has been associated with microstructural properties of the cerebellar peduncles, the white matter pathways connecting the cerebellum to the cerebrum. In this study, we used two independent neuroimaging modalities to assess which features of the cerebellar peduncles would be associated with reading. Twenty-three 8-year-old children were evaluated on word reading efficiency and imaged using diffusion MRI (dMRI) and quantitative T1 relaxometry (qT1). We segmented the superior (SCP), middle, and inferior cerebellar peduncles and extracted two metrics: fractional anisotropy (FA) from dMRI and R1 from qT1. Tract-FA was significantly correlated with tract-R1 in left and right SCPs (left: r_P(21) = .63, right: r_P(21) = .76, p ≤ .001) suggesting that FA of these peduncles, at least in part, indexed myelin content. Tract-FA and tract R1 were not correlated in the other cerebellar peduncles. Reading efficiency negatively correlated with tract-FA of the left (r_P(21) = - .43, p = .040) and right SCP (r_P(21) = - .37, p = .079). Reading efficiency did not correlate with tract-R1 in the SCPs. The negative association of reading efficiency with tract-FA and the lack of association of reading efficiency with tract-R1 implicate properties other than myelin content as relevant to the information flow between the cerebellum and the cerebrum for individual differences in reading skills in children.

Investigating the effects of handedness on the consistency of lateralization for speech production and semantic processing tasks using functional transcranial Doppler sonography

The left hemisphere is dominant for language in most people, but lateralization strength varies between different tasks and individuals. A large body of literature has shown that handedness is associated with lateralization: left handers have weaker language lateralization on average, and a greater incidence of atypical (right hemisphere) lateralization; but typically, these studies have relied on a single measure of language lateralization. Here we consider the relationships between lateralization for two different language tasks. We investigated the influence of handedness on lateralization using functional transcranial Doppler sonography (fTCD), using an existing dataset (N = 151 adults, 21 left handed). We compared a speech production task (word generation) and a semantic association task. We demonstrated stronger left-lateralization for word generation than semantic association; and a moderate correlation between laterality indices for the two tasks (r = 0.59). Laterality indices were stronger for right than left handers, and left handers were more likely than right handers to have atypical (right hemisphere) lateralization or inconsistent lateralization between the two tasks. These results add to our knowledge of individual differences in lateralization and support the view that language lateralization is multifactorial rather than unitary.

NFB-11. WHITE MATTER DIFFERENCES IN CHILDREN WITH NF1 COMPARED TO CONTROLS

INTRODUCTION

Neurofibromatosis type 1 (NF1) is a genetic condition in which children develop learning challenges and glioma. White matter tracts (WMT) are implicated in these cognitive functions, while oligodendroglial precursor cells are implicated in both gliomagenesis and white-matter development. Specific WMTs have not been well characterized in NF1.

METHODS

Twenty NF1 patients aged 1.4–17.6 years (M = 9.5 years, 24 male) and 20 age-and-sex-matched controls underwent dMRI at 3T (25 directions, b=1000 s/mm²). Automated segmentation of WMTs extracted fractional anisotropy (FA) and mean diffusivity (MD) of 18 major WMTs. Covariance analysis examined the effect of group (NF1/controls) on FA/MD after controlling for intracranial volume. Regression analyses for WMTs determined the interaction of FA/MD with age for NF1 patients compared to controls. Significance was set at p<0.05 after correcting for multiple comparisons using false discovery rate.

RESULTS

Compared to controls, children with NF1 had significantly decreased FA in 8 and increased MD in 12/18 tracts. Differences held after controlling for intracranial volume. The interaction between group and age accounted for a significant proportion of the variance in FA in 9 and in MD in 16/18 tracts. FA and MD differences between children with NF1 and controls were greater at younger than older ages.

CONCLUSION

Microstructural differences were observed in WMTs in children with NF1 compared to controls. These differences were not explained by intracranial volume and were most pronounced in younger children with NF1 compared to controls. These findings have implications for understanding neurocognitive deficits and gliomagenesis observed in children with NF1.

Neonatal white matter tract microstructure and 2-year language outcomes after preterm birth

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Preterm infant white matter tracts uniquely predict later toddler language.

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Neonatal medical history moderates posterior corpus callosum–language relations.

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Different associations by tract may relate to brain maturation and medical history.

Aim

To determine whether variability in diffusion MRI (dMRI) white matter tract metrics, obtained in a cohort of preterm infants prior to neonatal hospital discharge, would be associated with language outcomes at age 2 years, after consideration of age at scan and number of major neonatal complications.

Method

30 children, gestational age 28.9 (2.4) weeks, underwent dMRI at mean post menstrual age 36.4 (1.4) weeks and language assessment with the Bayley Scales of Infant Development–III at mean age 22.2 (1.7) months chronological age. Mean fractional anisotropy (FA) and mean diffusivity (MD) were calculated for 5 white matter tracts. Hierarchical linear regression assessed associations between tract FA, moderating variables, and language outcomes.

Results

FA of the left inferior longitudinal fasciculus accounted for 17% (p = 0.03) of the variance in composite language and FA of the posterior corpus callosum accounted for 19% (p = 0.02) of the variance in composite language, beyond that accounted for by post-menstrual age at scan and neonatal medical complications. The number of neonatal medical complications moderated the relationship between language and posterior corpus callosum FA but did not moderate the association in the other tract.

Conclusion

Language at age 2 is associated with white matter metrics in early infancy in preterm children. The different pattern of associations by fiber group may relate to the stage of brain maturation and/or the nature and timing of medical complications related to preterm birth. Future studies should replicate these findings with a larger sample size to assure reliability of the findings.

Age-Dependent White Matter Characteristics of the Cerebellar Peduncles from Infancy Through Adolescence

Cerebellum-cerebrum connections are essential for many motor and cognitive functions and cerebellar disorders are prevalent in childhood. The middle (MCP), inferior (ICP), and superior cerebellar peduncles (SCP) are the major white matter pathways that permit communication between the cerebellum and the cerebrum. Knowledge about the microstructural properties of these cerebellar peduncles across childhood is limited. Here, we report on a diffusion magnetic resonance imaging tractography study to describe age-dependent characteristics of the cerebellar peduncles in a cross-sectional sample of infants, children, and adolescents from newborn to 17 years of age (N = 113). Scans were collected as part of clinical care; participants were restricted to those whose scans showed no abnormal findings and whose history and exam had no risk factors for cerebellar abnormalities. A novel automated tractography protocol was applied. Results showed that mean tract-FA increased, while mean tract-MD decreased from infancy to adolescence in all peduncles. Rapid changes were observed in both diffusion measures in the first 24 months of life, followed by gradual change at older ages. The shape of the tract profiles was similar across ages for all peduncles. These data are the first to characterize the variability of diffusion properties both across and within cerebellar white matter pathways that occur from birth through later adolescence. The data represent a rich normative data set against which white matter alterations seen in children with posterior fossa conditions can be compared. Ultimately, the data will facilitate the identification of sensitive biomarkers of cerebellar abnormalities.

Stereotactic laser ablation for completion corpus callosotomy

OBJECTIVE

Completion corpus callosotomy can offer further remission from disabling seizures when a prior partial corpus callosotomy has failed and residual callosal tissue is identified on imaging. Traditional microsurgical approaches to section residual fibers carry risks associated with multiple craniotomies and the proximity to the medially oriented motor cortices. Laser interstitial thermal therapy (LITT) represents a minimally invasive approach for the ablation of residual fibers following a prior partial corpus callosotomy. Here, the authors report clinical outcomes of 6 patients undergoing LITT for completion corpus callosotomy and characterize the radiological effects of ablation.

METHODS

A retrospective clinical review was performed on a series of 6 patients who underwent LITT completion corpus callosotomy for medically intractable epilepsy at Stanford University Medical Center and Lucile Packard Children's Hospital at Stanford between January 2015 and January 2018. Detailed structural and diffusion-weighted MR images were obtained prior to and at multiple time points after LITT. In 4 patients who underwent diffusion tensor imaging (DTI), streamline tractography was used to reconstruct and evaluate tract projections crossing the anterior (genu and rostrum) and posterior (splenium) parts of the corpus callosum. Multiple diffusion parameters were evaluated at baseline and at each follow-up.

RESULTS

Three pediatric (age 8-18 years) and 3 adult patients (age 30-40 years) who underwent completion corpus callosotomy by LITT were identified. Mean length of follow-up postoperatively was 21.2 (range 12-34) months. Two patients had residual splenium, rostrum, and genu of the corpus callosum, while 4 patients had residual splenium only. Postoperative complications included asymptomatic extension of ablation into the left thalamus and transient disconnection syndrome. Ablation of the targeted area was confirmed on immediate postoperative diffusion-weighted MRI in all patients. Engel class I-II outcomes were achieved in 3 adult patients, whereas all 3 pediatric patients had Engel class III-IV outcomes. Tractography in 2 adult and 2 pediatric patients revealed time-dependent reduction of fractional anisotropy after LITT.

CONCLUSIONS

LITT is a safe, minimally invasive approach for completion corpus callosotomy. Engel outcomes for completion corpus callosotomy by LITT were similar to reported outcomes of open completion callosotomy, with seizure reduction primarily observed in adult patients. Serial DTI can be used to assess the presence of tract projections over time but does not classify treatment responders or nonresponders.

Arterial spin labeling perfusion changes of the frontal lobes in children with posterior fossa syndrome

OBJECTIVE

Posterior fossa syndrome (PFS) is a common complication following the resection of posterior fossa tumors in children. The pathophysiology of PFS remains incompletely elucidated; however, the wide-ranging symptoms of PFS suggest the possibility of widespread cortical dysfunction. In this study, the authors utilized arterial spin labeling (ASL), an MR perfusion modality that provides quantitative measurements of cerebral blood flow without the use of intravenous contrast, to assess cortical blood flow in patients with PFS.

METHODS

A database of medulloblastoma treated at the authors' institution from 2004 to 2016 was retrospectively reviewed, and 14 patients with PFS were identified. Immediate postoperative ASL for patients with PFS and medulloblastoma patients who did not develop PFS were compared. Additionally, in patients with PFS, ASL following the return of speech was compared with immediate postoperative ASL.

RESULTS

On immediate postoperative ASL, patients who subsequently developed PFS had statistically significant decreases in right frontal lobe perfusion and a trend toward decreased perfusion in the left frontal lobe compared with controls. Patients with PFS had statistically significant increases in bilateral frontal lobe perfusion after the resolution of symptoms compared with their immediate postoperative imaging findings.

CONCLUSIONS

ASL perfusion imaging identifies decreased frontal lobe blood flow as a strong physiological correlate of PFS that is consistent with the symptomatology of PFS. This is the first study to demonstrate that decreases in frontal lobe perfusion are present in the immediate postoperative period and resolve with the resolution of symptoms, suggesting a physiological explanation for the transient symptoms of PFS.

Posterior fossa syndrome and increased mean diffusivity in the olivary bodies

OBJECTIVE

Posterior fossa syndrome (PFS) is a common postoperative complication following resection of posterior fossa tumors in children. It typically presents 1 to 2 days after surgery with mutism, ataxia, emotional lability, and other behavioral symptoms. Recent structural MRI studies have found an association between PFS and hypertrophic olivary degeneration, which is detectable as T2 hyperintensity in the inferior olivary nuclei (IONs) months after surgery. In this study, the authors investigated whether immediate postoperative diffusion tensor imaging (DTI) of the ION can serve as an early imaging marker of PFS.

METHODS

The authors retrospectively reviewed pediatric brain tumor patients treated at their institution, Lucile Packard Children's Hospital at Stanford, from 2004 to 2016. They compared the immediate postoperative DTI studies obtained in 6 medulloblastoma patients who developed PFS to those of 6 age-matched controls.

RESULTS

Patients with PFS had statistically significant increased mean diffusivity (MD) in the left ION (1085.17 ± 215.51 vs 860.17 ± 102.64, p = 0.044) and variably increased MD in the right ION (923.17 ± 119.2 vs 873.67 ± 60.16, p = 0.385) compared with age-matched controls. Patients with PFS had downward trending fractional anisotropy (FA) in both the left (0.28 ± 0.06 vs 0.23 ± 0.03, p = 0.085) and right (0.29 ± 0.06 vs 0.25 ± 0.02, p = 0.164) IONs compared with age-matched controls, although neither of these values reached statistical significance.

CONCLUSIONS

Increased MD in the ION is associated with development of PFS. ION MD changes may represent an early imaging marker of PFS.

White Matter Plasticity in Reading-Related Pathways Differs in Children Born Preterm and at Term: A Longitudinal Analysis

Children born preterm (PT) are at risk for white matter injuries based on complications of prematurity. They learn to read but on average perform below peers born full term (FT). Studies have yet to establish whether properties of white matter pathways at the onset of learning to read are associated with individual variation later in reading development in PT children. Here, we asked whether fractional anisotropy (FA) at age 6 years is associated with reading outcome at age 8 years in PT children in the same pathways as previously demonstrated in a sample of FT children. PT (n = 34, mean gestational age = 29.5 weeks) and FT children (n = 37) completed diffusion MRI and standardized measures of non-verbal IQ, language, and phonological awareness at age 6 years. Reading skills were assessed at age 8 years. Mean tract-FA was extracted from pathways that predicted reading outcome in children born FT: left arcuate fasciculus (Arc), bilateral superior longitudinal fasciculus (SLF), and left inferior cerebellar peduncle (ICP). We explored associations in additional pathways in the PT children: bilateral inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, and uncinate fasciculus. Linear regression models examined whether the prediction of reading outcome at age 8 years based on mean tract-FA at age 6 years was moderated by birth group. Children born PT and FT did not differ significantly in tract-FA at age 6 years or in reading at age 8 years. Sex, socioeconomic status, and non-verbal IQ at age 6 years were associated with reading outcome and were included as covariates in all models. Birth group status significantly moderated associations between reading outcome and mean tract-FA only in the left Arc, right SLF, and left ICP, before and after consideration of pre-literacy skills. Microstructural properties of these cerebral and cerebellar pathways predicted later reading outcome in FT but not in PT children. Children born PT may rely on alternative pathways to achieve fluent reading. These findings have implications for plasticity of neural organization after early white matter injury.

Microstructural properties of white matter pathways in relation to subsequent reading abilities in children: a longitudinal analysis

Microstructural properties of white matter pathways are associated with concurrent reading abilities in children. In this longitudinal study, we asked whether properties of white matter pathways at the onset of learning to read would be associated with reading abilities at older ages. Children (N = 37) with a wide range of reading abilities completed standardized measures of language and phonological awareness and diffusion MRI at age 6 years. Mean tract-fractional anisotropy (FA) was extracted from reading-related pathways. At age 8, the same children were re-assessed using a standardized reading measure. Using linear regressions, we examined the contribution of tract-FA at age 6 to reading outcome at age 8, beyond known demographic and pre-literacy predictors of reading. Tract-FA of the left arcuate, left and right superior longitudinal fasciculus (SLF), and left inferior cerebellar peduncle (ICP) made unique contributions to reading outcome after consideration of sex and family history of reading delays. Tract-FA of the left and right SLF and left ICP made unique contributions to reading outcome after the addition of pre-literacy skills. Thus, cerebellar and bilateral cortical pathways represented a network associated with subsequent reading abilities. Early white matter properties may be associated with other neuropsychological functions that predict reading or may influence reading development, independent of reading-related abilities. Tract FA at early stages of learning to read may serve as a biomarker of later reading abilities.

Long-Term Supratentorial Radiologic Effects of Surgery and Local Radiation in Children with Infratentorial Ependymoma

BACKGROUND

Current standard of care for children with infratentorial ependymoma includes maximal safe resection and local radiation of 54-59 Gray. High-dose local radiation has been associated with declines in multiple cognitive domains. The anatomic and physiologic correlates of this cognitive decline remain undefined, and there have been no radiographic studies on the long-term effects of this treatment paradigm.

METHODS

A comprehensive database of pediatric brain tumor patients treated at Stanford Children's from 2004-2016 was queried. Seven patients with posterior fossa ependymoma who were treated with surgery and local radiation alone, who had no evidence of recurrent disease, and had imaging suitable for analysis were identified. Diffusion-weighted magnetic resonance imaging datasets were used to calculate apparent diffusion coefficient maps for each subject, while arterial spin labeling datasets were used to calculate maps of cerebral blood flow. Diffusion-weighted imaging and arterial spin labeling datasets of 52 age-matched healthy children were analyzed in the same fashion to enable group comparisons.

RESULTS

Several statistically significant differences were detected between the 2 groups. Cerebral blood flow was lower in the caudate and pallidum and higher in the nucleus accumbens in the ependymoma cohort compared with controls. Apparent diffusion coefficient was increased in the thalamus and trended toward decreased in the amygdala.

CONCLUSIONS

Surgery and local radiation for posterior fossa ependymoma are associated with supratentorial apparent diffusion coefficient and cerebral blood flow alterations, which may represent an anatomic and physiologic correlate to the previously published decline in neurocognitive outcomes in this population.

Framework for shape analysis of white matter fiber bundles

Diffusion imaging coupled with tractography algorithms allows researchers to image human white matter fiber bundles in-vivo. These bundles are three-dimensional structures with shapes that change over time during the course of development as well as in pathologic states. While most studies on white matter variability focus on analysis of tissue properties estimated from the diffusion data, e.g. fractional anisotropy, the shape variability of white matter fiber bundle is much less explored. In this paper, we present a set of tools for shape analysis of white matter fiber bundles, namely: (1) a concise geometric model of bundle shapes; (2) a method for bundle registration between subjects; (3) a method for deformation estimation. Our framework is useful for analysis of shape variability in white matter fiber bundles. We demonstrate our framework by applying our methods on two datasets: one consisting of data for 6 normal adults and another consisting of data for 38 normal children of age 11 days to 8.5 years. We suggest a robust and reproducible method to measure changes in the shape of white matter fiber bundles. We demonstrate how this method can be used to create a model to assess age-dependent changes in the shape of specific fiber bundles. We derive such models for an ensemble of white matter fiber bundles on our pediatric dataset and show that our results agree with normative human head and brain growth data. Creating these models for a large pediatric longitudinal dataset may improve understanding of both normal development and pathologic states and propose novel parameters for the examination of the pediatric brain.