Assessment of cerebral microbleeds by susceptibility-weighted imaging in Alzheimer's disease patients: A neuroimaging biomarker of the disease

Purpose The objective of this study was to correlate the presence and distribution of cerebral microbleeds in Alzheimer's disease patients with cerebrospinal fluid biomarkers (amyloid-beta and phosphorylated tau 181 protein levels) and cognitive decline by using susceptibility-weighted imaging magnetic resonance sequences at 1.5 T. Material and methods Fifty-four consecutive Alzheimer's disease patients underwent brain magnetic resonance imaging at 1.5 T to assess the presence and distribution of cerebral microbleeds on susceptibility-weighted imaging images. The images were analyzed in consensus by two neuroradiologists, each with at least 10 years' experience. Dementia severity was assessed with the Mini-Mental State Examination score. A multiple regression analysis was performed to assess the associations between the number and location of cerebral microbleed lesions with the age, sex, duration of the disease, cerebrospinal fluid amyloid-beta and phosphorylated tau 181 protein levels, and cognitive functions. Results A total of 296 microbleeds were observed in 54 patients; 38 patients (70.4%) had lobar distribution, 13 patients (24.1%) had non-lobar distribution, and the remaining three patients (5.6%) had mixed distribution, demonstrating that Alzheimer's disease patients present mainly a lobar distribution of cerebral microbleeds. The age and the duration of the disease were correlated with the number of lobar cerebral microbleeds (P < 0.001). Cerebrospinal fluid amyloid-beta, phosphorylated tau 181 protein levels, and cognitive decline were correlated with the number of lobar cerebral microbleeds in Alzheimer's disease patients (P < 0.001). Conclusion Lobar distribution of cerebral microbleeds is associated with Alzheimer's disease and the number of lobar cerebral microbleeds directly correlates with cerebrospinal fluid amyloid-beta and phosphorylated tau 181 protein levels and with the cognitive decline of Alzheimer's disease patients

Venous gas embolism as a predictive tool for improving CNS decompression safety

A key process in the pathophysiological steps leading to decompression sickness (DCS) is the formation of inert gas bubbles. The adverse effects of decompression are still not fully understood, but it seems reasonable to suggest that the formation of venous gas emboli (VGE) and their effects on the endothelium may be the central mechanism leading to central nervous system (CNS) damage. Hence, VGE might also have impact on the long-term health effects of diving. In the present review, we highlight the findings from our laboratory related to the hypothesis that VGE formation is the main mechanism behind serious decompression injuries. In recent studies, we have determined the impact of VGE on endothelial function in both laboratory animals and in humans. We observed that the damage to the endothelium due to VGE was dose dependent, and that the amount of VGE can be affected both by aerobic exercise and exogenous nitric oxide (NO) intervention prior to a dive. We observed that NO reduced VGE during decompression, and pharmacological blocking of NO production increased VGE formation following a dive. The importance of micro-nuclei for the formation of VGE and how it can be possible to manipulate the formation of VGE are discussed together with the effects of VGE on the organism. In the last part of the review we introduce our thoughts for the future, and how the enigma of DCS should be approached

TC perfusionale nell'ischemia cerebrale acuta: Valore predittivo dei parametri di perfusione cerebrale nel discriminare il tessuto vitale da quello infartuato

Purpose. The aim of this study was to assess the value of computed tomography (CT) perfusion parameters in differentiating tissue viability in acute stoke patients. Materials and methods. Thirteen patients (mean age 63.3 years) with nonhaemorrhagic stroke underwent multidetector perfusion CT within 3 h of symptom onset. Images were continuously acquired at the basal ganglia over 40 s during injection of 90 ml of iodinated contrast medium injected at a rate of 9 ml/s with a 9-s delay. Z-axis coverage was 20 mm. All patients underwent diffusion-weighted magnetic resonance imaging (DWI) within 12 h of perfusion CT to define the extent of the infarct. Perfusion CT data were analysed in regions of interests (ROIs) on regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF) and mean transit time (MTT) maps placed in various parts of the perfusiondeficient territory and in the contralateral hemisphere. Statistical analysis was performed using the analysis of variance (ANOVA) test to assess differences in CT perfusion parameters. Receiver operator characteristics (ROC) analysis was performed to assess possible threshold values that predict tissue infarction vs. viability. Results. Normal CT findings with abnormal CT perfusion parameters were seen in the region of infarction and in the viable tissue (penumbra) within a 1.5-cm distance from the infarct margin as outlined on DWI images. Infarcted areas demonstrated significant prolongation of MTT values compared with noninfarcted areas (p6.05 s identify infarcted tissue. © 2007 Springer-Verlag

Clinical Severity in Different Waves of SARS-CoV-2 Infection in Sicily: A Model of Smith’s “Law of Declining Virulence” from Real-World Data

Background: The COVID-19 epidemic had a rapid spread worldwide with a continuous and fast mutation of the virus, resulting in the emergence of several variants of concern (VOC). The aim of this study was to evaluate the severity of each VOC among SARS-CoV-2 infected subjects by investigating deaths, ICU admissions, intubations, and severe critical symptoms. Methods: An ecological observational study was performed to evaluate mortality rates and clinical characteristics of 321,490 unvaccinated Sicilian SARS-CoV-2 cases observed from 2 March 2020 to 27 March 2022. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by multivariate logistic regression analysis evaluating factors determining a clinical worsening. Results: Delta (adj-OR 3.00, 95% Cls 2.70–3.33) and wild-type (adj-OR 2.41, 95% Cls 2.2–2.62) variants had a higher risk than the Omicron strain for developing critical COVID-19 necessitating intubation and eventually undergoing death. Moreover, males appeared to be significantly more susceptible to developing the worst clinical outcome considered, as did older subjects. Conclusions: The present study provides evidence of factors implicated in the worsening of SARS-CoV-2-infection-related clinical outcomes. The study highlighted the different roles of VOC, in particular Delta and wild-type, and being male and elderly in the development of a worse clinical outcome

Brain Core Temperature of Patients Before and After Orthotopic Liver Transplantation Assessed by DWI-Thermometry

Purpose The brain produces heat as a result of cerebral metabolism, and the heat is removed mainly through circulation of the intracranial blood vessels and cerebrospinal fluid (CSF). The aim of this study was to assess the brain core temperature of adult patients with end stage liver disease before and after orthotopic liver transplantation (OLT) using a noninvasive temperature measurement technique based on the diffusion coefficient of the cerebrospinal fluid. Materials and Methods This retrospective study used the data collected from January, 2014 to January, 2017. The study group comprised 19 patients (16 men, 3 women, mean age 57.9 ± 7.4 years) with a MELD score 23.7 who underwent magnetic resonance (MR) imaging before OLT and within 30 days after OLT. The etiology of end stage liver diseases was determined as follow: drug-related fulminant hepatic failure (n=1), nonalcoholic steatohepatitis (n=3), hepatocellular carcinoma (n=8), HCV/HBV/HDV infection (n=3), primary biliary cholangitis (n=1), acute liver failure on chronic sclerosing cholangitis (n=1), cryptogenic cirrhosis (n=1) and liver cirrhosis (n.=1). MR imaging studies were performed with a 1.5T MR scanner. Brain core temperature (T: °C) was calculated using the following equation from the diffusion coefficient (D) in the lateral ventricular (LV): CSF: T = 2256.74/ln (4.39221/D) - 273.15 using a standard DWI single-shot echo-planar pulse sequence (b value 1000 s/mm2). Statistical analysis was performed using a nonparametric Mann-Whitney U test. Results Brain core temperature measurements were successfully performed in all patients before and after OLT. Mean (± standard deviation) measured LV temperature was 38.67 ± 1.76 °C before OLT and 38.60 ± 0.99 °C after OLT, showing no significant difference (P = 0.643). Conclusions Brain core temperature was stable in patients undergoing OLT. Brain core thermometry using DWI-based MR imaging may provide a supplementary brain biomarker to confirm that cerebral blood flow and cerebral metabolism are stable during OLT