Assessment of brain damage and plasticity in the visual system due to early occipital lesion: comparison of FDG-PET with diffusion MRI tractography

Executive functioning in children with posterior cortex epilepsy compared to temporal and frontal lobe epilepsies

OBJECTIVE

People with epilepsy are at an increased risk of experiencing executive dysfunction, particularly those with frontal lobe epilepsy (FLE). The literature has also demonstrated alterations in executive functioning (EF) in patients with temporal lobe epilepsy (TLE). However, few studies have examined the neuropsychological profile of posterior cortex epilepsy (PCE), and little attention has been given to cognitive impairments in the pediatric population with PCE. This study aims to investigate EF performance in children with drug-resistant PCE compared to patients with FLE and TLE.

METHODS

We analyzed neuropsychological data from 217 patients aged 6-18 years who underwent preoperative evaluation for epilepsy surgery. The EF of patients with PCE was compared to patients with FLE and TLE.

RESULTS

There was no significant difference in Full-Scale Intelligence Quotient (FSIQ) means between groups. However, we found a significant effect of brain region on the Coding task, in which patients with PCE and FLE performed worse than those with TLE (p = 0.034). We also observed performance differences between groups on the Stroop test (p = 0.005), with patients with PCE and FLE performing worse than the TLE group.

SIGNIFICANCE

These findings suggest that children with PCE have alterations in their EF that are similar to the deficits found in FLE compared to patients with TLE. This emphasizes the importance of understanding the neuroanatomy of executive functions and the model of neural networks extending beyond the prefrontal cortex.

Study protocol: retrospectively mining multisite clinical data to presymptomatically predict seizure onset for individual patients with Sturge-Weber

INTRODUCTION

Secondary analysis of hospital-hosted clinical data can save time and cost compared with prospective clinical trials for neuroimaging biomarker development. We present such a study for Sturge-Weber syndrome (SWS), a rare neurovascular disorder that affects 1 in 20 000-50 000 newborns. Children with SWS are at risk for developing neurocognitive deficit by school age. A critical period for early intervention is before 2 years of age, but early diagnostic and prognostic biomarkers are lacking. We aim to retrospectively mine clinical data for SWS at two national centres to develop presymptomatic biomarkers.

METHODS AND ANALYSIS

We will retrospectively collect clinical, MRI and neurocognitive outcome data for patients with SWS who underwent brain MRI before 2 years of age at two national SWS care centres. Expert review of clinical records and MRI quality control will be used to refine the cohort. The merged multisite data will be used to develop algorithms for abnormality detection, lesion-symptom mapping to identify neural substrate and machine learning to predict individual outcomes (presence or absence of seizures) by 2 years of age. Presymptomatic treatment in 0-2 years and before seizure onset may delay or prevent the onset of seizures by 2 years of age, and thereby improve neurocognitive outcomes. The proposed work, if successful, will be one of the largest and most comprehensive multisite databases for the presymptomatic phase of this rare disease.

ETHICS AND DISSEMINATION

This study involves human participants and was approved by Boston Children's Hospital Institutional Review Board: IRB-P00014482 and IRB-P00025916 Johns Hopkins School of Medicine Institutional Review Board: NA_00043846. Participants gave informed consent to participate in the study before taking part. The Institutional Review Boards at Kennedy Krieger Institute and Boston Children's Hospital approval have been obtained at each site to retrospectively study this data. Results will be disseminated by presentations, publication and sharing of algorithms generated.

Hypermetabolism on Pediatric PET Scans of Brain Glucose Metabolism: What Does It Signify?

When one is interpreting clinical 18F-FDG PET scans of the brain (excluding tumors) in children, the typical abnormality seen is hypometabolism of various brain regions. Focal areas of hypermetabolism are noted occasionally, and the usual interpretation is that the hypermetabolic region represents a seizure focus. In this review, I discuss and illustrate the multiple causes of hypermetabolism on 18F-FDG PET studies that should not be interpreted as seizure activity, as such an interpretation could potentially be incorrect. Various conditions in which focal hypermetabolism can be encountered on 18F-FDG PET studies include interictal hypermetabolism, Sturge-Weber syndrome, changes associated with brain plasticity after injury, Rett syndrome, hypoxic-ischemic brain injury, various inborn errors of metabolism, and autoimmune encephalitis. The radiologist or nuclear medicine physician interpreting clinical 18F-FDG PET studies should be aware of these circumstances to accurately assess the findings.

Consensus Statement for the Management and Treatment of Sturge-Weber Syndrome: Neurology, Neuroimaging, and Ophthalmology Recommendations

BACKGROUND

Sturge-Weber syndrome (SWS) is a sporadic, neurocutaneous syndrome involving the skin, brain, and eyes. Because of the variability of the clinical manifestations and the lack of prospective studies, consensus recommendations for management and treatment of SWS have not been published.

OBJECTIVE

This article consolidates the current literature with expert opinion to make recommendations to guide the neuroimaging evaluation and the management of the neurological and ophthalmologic features of SWS.

METHODS

Thirteen national peer-recognized experts in neurology, radiology, and ophthalmology with experience treating patients with SWS were assembled. Key topics and questions were formulated for each group and included (1) risk stratification, (2) indications for referral, and (3) optimum treatment strategies. An extensive PubMed search was performed of English language articles published in 2008 to 2018, as well as recent studies identified by the expert panel. The panel made clinical practice recommendations.

CONCLUSIONS

Children with a high-risk facial port-wine birthmark (PWB) should be referred to a pediatric neurologist and a pediatric ophthalmologist for baseline evaluation and periodic follow-up. In newborns and infants with a high-risk PWB and no history of seizures or neurological symptoms, routine screening for brain involvement is not recommended, but brain imaging can be performed in select cases. Routine follow-up neuroimaging is not recommended in children with SWS and stable neurocognitive symptoms. The treatment of ophthalmologic complications, such as glaucoma, differs based on the age and clinical presentation of the patient. These recommendations will help facilitate coordinated care for patients with SWS and may improve patient outcomes.

Deep cerebral vein expansion with metabolic and neurocognitive recovery in Sturge-Weber syndrome

We present longitudinal imaging data of a child with Sturge–Weber syndrome (SWS). At age 8 months, 3 weeks after initial seizures and prolonged motor deficit, MRI showed extensive right hemispheric SWS involvement with severe glucose hypometabolism on PET. She was treated with levetiracetam and aspirin. Follow‐up imaging at age 29 months showed a robust interval expansion of enlarged deep medullary veins throughout the affected hemisphere along with a dramatic recovery of hemispheric metabolism and normalized neurocognitive functioning. These findings demonstrate a robust, multilobar hemispheric remodeling of deep venous collaterals that likely contributed to reversal of initial metabolic and neurocognitive deficits.

Function-structure connectivity in patients with severe brain injury as measured by MRI-DWI and FDG-PET

A vast body of literature exists showing functional and structural dysfunction within the brains of patients with disorders of consciousness. However, the function (fluorodeoxyglucose FDG-PET metabolism)-structure (MRI-diffusion-weighted images; DWI) relationship and how it is affected in severely brain injured patients remains ill-defined. FDG-PET and MRI-DWI in 25 severely brain injured patients (19 Disorders of Consciousness of which 7 unresponsive wakefulness syndrome, 12 minimally conscious; 6 emergence from minimally conscious state) and 25 healthy control subjects were acquired here. Default mode network (DMN) function-structure connectivity was assessed by fractional anisotropy (FA) and metabolic standardized uptake value (SUV). As expected, a profound decline in regional metabolism and white matter integrity was found in patients as compared with healthy subjects. Furthermore, a function-structure relationship was present in brain-damaged patients between functional metabolism of inferior-parietal, precuneus, and frontal regions and structural integrity of the frontal-inferiorparietal, precuneus-inferiorparietal, thalamo-inferioparietal, and thalamofrontal tracts. When focusing on patients, a stronger relationship between structural integrity of thalamo-inferiorparietal tracts and thalamic metabolism in patients who have emerged from the minimally conscious state as compared with patients with disorders of consciousness was found. The latter finding was in line with the mesocircuit hypothesis for the emergence of consciousness. The findings showed a positive function-structure relationship within most regions of the DMN. Hum Brain Mapp 37:3707-3720, 2016. © 2016 Wiley Periodicals, Inc.

Metabolic correlates of cognitive function in children with unilateral Sturge-Weber syndrome: Evidence for regional functional reorganization and crowding

To evaluate metabolic changes in the ipsi- and contralateral hemisphere in children showing a cognitive profile consistent with early reorganization of cognitive function, we evaluated the regional glucose uptake, interhemispheric metabolic connectivity, and cognitive function in children with unilateral SWS. Interictal 2-deoxy-2[¹⁸ F]fluoro-D-glucose (FDG)-PET scans of 27 children with unilateral SWS and mild epilepsy and 27 age-matched control (non-SWS children with epilepsy and normal FDG-PET) were compared using statistical parametric mapping (SPM). Regional FDG-PET abnormalities calculated as SPM(t) scores in the SWS group were correlated with cognitive function (IQ) in left- and right-hemispheric subgroups. Interhemispheric metabolic connectivity between homotopic cortical regions was also calculated. Verbal IQ was substantially (≥10 points difference) higher than non-verbal IQ in 61% of the right- and 71% of the left-hemispheric SWS group. FDG SPM(t) scores in the affected hemisphere showed strong positive correlations with IQ in the left-hemispheric, but not in right-hemispheric SWS group in several frontal, parietal, and temporal cortical regions. Significant positive interhemispheric metabolic connectivity, present in controls, was diminished in the SWS group. In addition, the left-hemispheric SWS group showed inverse metabolic interhemispheric correlations in specific parietal, temporal, and occipital regions. FDG SPM(t) scores in the same regions of the right (unaffected) hemisphere showed inverse correlations with IQ. These findings suggest that left-hemispheric lesions in SWS often result in early reorganization of verbal functions while interfering with ("crowding") their non-verbal cognitive abilities. These cognitive changes are associated with specific metabolic abnormalities in the contralateral hemisphere not directly affected by SWS.

Visual outcome in Sturge-Weber syndrome: a systematic review and Dutch multicentre cohort

Visual functions in Sturge-Weber syndrome (SWS) may be impaired by glaucoma, diffuse choroidal haemangioma (DCH) or leptomeningeal angioma. The aim of this study was to gain better insight in the visual deficits of SWS patients. A systematic literature search using PubMed and Embase medical databases was performed to identify articles describing visual acuity (VA) and/or visual field (VF) findings in SWS patients. In addition, a Dutch multicentre cohort with 33 SWS patients was collected and the combined results of VA and VF findings are presented. Visual acuity results of 25 studies and VF results of 12 studies were suitable for data extraction. Description of the combination of both VA and VF findings was scarce. Homonymous hemianopia (HH) was present in 42% of SWS patients. Seventy per cent of eyes had a (near) normal vision, while VA of eyes with glaucoma or DCH was severely impaired in 28% and 67%, respectively. In the Dutch cohort, only 18% (6/33) of patients had (near) normal findings of both visual parameters. In addition, half of the patients with glaucoma suffered from a combination of a HH and VA impairment. In conclusion, although SWS patients are exposed to severe functional visual impairment due to the possible cumulative consequences of glaucoma, DCH and cerebral injury, description of the combination of both VA and VF results is scarce in the literature. Particularly, the combination of visual impairment due to glaucoma or DCH, and HH might be invalidating.