Mild encephalitis/encephalopathy with reversible splenial lesion (MERS) is a rare clinico-radiological entity characterized by the magnetic resonance imaging (MRI) finding of a reversible lesion in the corpus callosum, sometimes involved the symmetrical white matters. Many cases of child-onset MERS with various causes have been reported. However, adult-onset MERS is relatively rare. The clinical characteristics and pathophysiologiccal mechanisms of adult-onset MERS are not well understood. We reviewed the literature on adult-onset MERS in order to describe the characteristics of MERS in adults and to provide experiences for clinician. We reported a case of adult-onset MERS with acute urinary retension and performed literature search from PubMed and web of science databases to identify other adult-onset MERS reports from Januarary 2004 to March 2016. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was followed on selection process. And then we summarized the clinico-radiological features of adult-onset MERS. Twenty-nine adult-onset MERS cases were reviewed from available literature including the case we have. 86.2% of the cases (25/29) were reported in Asia, especially in Japan. Ages varied between 18 and 59 years old with a 12:17 female-to-male ratio. The major cause was infection by virus or bacteria. Fever and headache were the most common clinical manifestation, and acute urinary retention was observed in 6 patients. All patients recovered completely within a month. Adult-onset MERS is an entity with a broad clinico-radiological spectrum because of the various diseases and conditions. There are similar characteristics between MERS in adults and children, also some differences.

Purpose: Enlarged perivascular spaces (EPVS) have been widely considered as a feature of cerebral small vessel disease (cSVD) but the pathogenesis of EPVS remains unclear. Compromised blood–brain barrier (BBB) integrity may play a role since previous studies have shown that BBB breakdown is a critical contributor to the pathogenesis of other cSVD markers. This study aimed to investigate the association of EPVS in the centrum semiovale (CSO) and basal ganglia (BG) with BBB permeability. Patients and methods: Consecutive participants free of symptomatic stroke history presented for physical examination were enrolled in this cross-sectional study. CSO- and BG-EPVS on T2-weighted (T2-W) magnetic resonance imaging (MRI) were rated using a five-point validated scale. Dynamic contrast-enhanced (DCE)-MRI and Patlak pharmacokinetic model were applied to quantify BBB permeability in the CSO and BG. Results: A total of 109 participants aged 49–90 years (mean age of 69.85 years) were enrolled. The proportions of participants presenting high-grade (>10) EPVS in the CSO and BG were 50.5% and 44.0%, respectively. After adjustments for potential confounders by logistic regression, leakage rate and fractional blood plasma volume were correlated with the severity of BG-EPVS (OR: 5.33; 95%CI: 1.95–14.60 and OR: 0.93; 95%CI: 0.87–0.99). Conclusion: Our study demonstrates that BG-EPVS are associated with compromised BBB integrity, supporting the hypothesis that the BBB dysfunction may be involved in the pathogenesis of BG-EPVS. EPVS in the CSO and BG may have distinct pathophysiology.

Objective: Several studies have demonstrated that compromised blood–brain barrier (BBB) integrity may play a pivotal role in the pathogenesis of individual cerebral small vessel disease (cSVD) markers, but the association between BBB permeability and total magnetic resonance imaging (MRI) cSVD burden remains unclear. This study aimed to investigate the relationship between BBB permeability and total MRI cSVD burden. Methods: Consecutive participants without symptomatic stroke history presented for physical examination were enrolled in this cross-sectional study. The presence of lacunes, white matter hyperintensities (WMH), cerebral microbleeds, and enlarged perivascular spaces was recorded in an ordinal score (range 0–4). We used dynamic contrast-enhanced-MRI and Patlak pharmacokinetic model to quantify BBB permeability in the normal-appearing white matter (NAWM), WMH, cortical gray matter (CGM), and deep gray matter (DGM). Results: All 99 participants averaged 70.33 years old (49–90 years). Multivariable linear regression analyses adjusted for age, sex, and vascular risk factors showed that leakage rate and area under the leakage curve in the NAWM, WMH, CGM, and DGM were positively associated with total MRI cSVD burden (all P < 0.01). Moreover, fractional blood plasma volumes in the NAWM, CGM, and DGM were negatively associated with total MRI cSVD burden (all P < 0.05). Conclusion: This study verified that compromised BBB integrity is associated with total MRI cSVD burden, suggesting that BBB dysfunction may be a critical contributor to the pathogenesis of cSVD. Longitudinal studies are required to determine whether there is a causal relationship between BBB permeability and total MRI cSVD burden.

Background: Blood-brain barrier (BBB) breakdown, as an early biomarker for vascular mild cognitive impairment (vMCI), has only been validated by a few studies. The aim of this study was to investigate whether compromised BBB integrity is involved in vMCI patients, and detect the relationship between BBB breakdown and cognitive function. BBB leakage in vMCI was explored, and the relationship between BBB leakage and cognitive function was discussed in this study. Methods: This is a cross-sectional study involving 26 vMCI patients and 21 sex- and age-matched healthy controls. Dynamic contrast-enhanced-magnetic resonance imaging was performed for all participants, to determine BBB leakage. Leakage volume, leakage rate, and fractional blood plasma volume (Vp) in the grey and white matter were evaluated. Neuropsychological tests were used to determine cognitive function. Leakage rate, leakage volume, and Vp in different brain locations, including deep grey matter, cortical grey matter, white matter hyperintensity, and normal-appearing white matter were compared between the two groups. Results: Multivariable linear regression analyses revealed that in all regions of interest, the leakage rate was significantly higher in vMCI patients relative to controls. Leakage volume in normal-appearing white matter and white matter hyperintensity were significantly higher, while Vp in normal-appearing white matter, deep grey matter, and cortical grey matter were significantly lower in vMCI patients. Moreover, Montreal Cognitive Assessment scores decreased with the increase of leakage rate in white matter hyperintensity. Conclusion: Increased BBB permeability was detected in vMCI patients and was related to cognitive decline, which suggested that BBB breakdown might be involved in cognitive dysfunction pathogenesis.

Enlarged perivascular spaces (EPVS) correlate with cognitive impairment and incident dementia. However, etiologies for severe basal ganglia EPVS (BG-EPVS) are still unclear. Our aim was to investigate the independent risk factors for severe BG-EPVS in patients with acute lacunar stroke. We prospectively identified patients with lacunar stroke (diameter on DWI ≤ 20mm) from Jan 2011 to May 2015. Patients with severe BG-EPVS were identified on T2 weighted MRI. Age (± 1 year) and sex matched controls were also recruited in the same population (two controls for one case). Vascular risk factors, clinical data, EPVS in centrum semiovale (rated 0 to 4), white matter hyperintensities (WMH) (by Fazekas scale), brain atrophy (rated 0 to 6) were compared between two groups. Logistic regression was performed to determine independent risk factors for severe BG-EPVS. During study period, 89 patients with severe BG-EPVS and 178 matched controls were included. Vascular risk factors did not differ between two groups. Patients with severe BG-EPVS had lower level of HbA1c and diastolic BP at admission, but presented with larger infarct size, more severe WMH (including total WMH, periventricular WMH and deep WMH) and brain atrophy. In logistic regression, brain atrophy (OR = 1.40; 95%CI 1.13, 1.73) and deep WMH (OR = 1.88; 95%CI 1.24, 2.83) were independent risk factors for severe BG-EPVS. Brain atrophy and deep WMH are independent risk factors for severe BG-EPVS, supporting the hypothesis that brain atrophy may be associated with the development of EPVS in basal ganglia.