Perifocal Edema in Patients with Meningioma is Associated with Impaired Whole-Brain Connectivity as Detected by Resting-State fMRI.

BACKGROUND AND PURPOSE: Meningiomas are intracranial tumors that usually carry a benign prognosis. Some meningiomas cause perifocal edema. Resting-state fMRI can be used to assess whole-brain functional connectivity, which can serve as a marker for disease severity. Here, we investigated whether the presence of perifocal edema in preoperative patients with meningiomas leads to impaired functional connectivity and if these changes are associated with cognitive function. MATERIALS AND METHODS: Patients with suspected meningiomas were prospectively included, and resting-state fMRI scans were obtained. Impairment of functional connectivity was quantified on a whole-brain level using our recently published resting-state fMRI-based marker, called the dysconnectivity index. Using uni- and multivariate regression models, we investigated the association of the dysconnectivity index with edema and tumor volume as well as cognitive test scores. RESULTS: Twenty-nine patients were included. In a multivariate regression analysis, there was a highly significant association of dysconnectivity index values and edema volume in the total sample and in a subsample of 14 patients with edema, when accounting for potential confounders like age and temporal SNR. There was no statistically significant association with tumor volume. Better neurocognitive performance was strongly associated with lower dysconnectivity index values. CONCLUSIONS: Resting-state fMRI showed a significant association between impaired functional connectivity and perifocal edema, but not tumor volume, in patients with meningiomas. We demonstrated that better neurocognitive function was associated with less impairment of functional connectivity. This result shows that our resting-state fMRI marker indicates a detrimental influence of peritumoral brain edema on global functional connectivity in patients with meningiomas.

Urinary levoglucosan levels in Austrian communities differing in agrarian quota.

Levoglucosan is a sugar anhydride produced by combustion of carbohydrates. In ambient monitoring it serves as an indicator for wood smoke. Its use in human biomonitoring, however, is not yet widespread. This study investigated whether levoglucosan in urine is a suitable biomarker for regional differences in wood smoke exposure in the winter season. Within the first Austrian biomonitoring survey, pooled urine samples from mothers as well as children of five communities of different size (two-stage random stratified sampling) were analysed by HPLC. As an indicator of exposure to polycyclic aromatic hydrocarbons (PAH) that are also prevalent in wood smoke, 1-hydroxypyrene was determined. In each town levoglucosan was found in higher levels in the pooled children's samples than in the pooled mothers' samples. It correlated well with the agrarian quota. 1-Hydroxypyrene concentrations were higher in areas with higher population density. Correlation of urinary levoglucosan concentrations with the agrarian quota may be explained by higher wood smoke exposure in communities with higher agrarian quota. To our knowledge this study is the first investigation on this issue in Europe. It indicates that human biomonitoring of levoglucosan may be suitable to detect differences in regional exposure to wood smoke.