Microdialysis, a technique for sampling the biochemical substances of extracellular fluid in vivo, has been widely utilized for physiological, pharmacological and pathological research. The principles and methodology of microdialysis and its applications in neurointensive care was reviewed.

Objective To explore the formation mechanism of peritumoral brain edema(PTBE)by vascular endothelial growth factor(VEGF).Methods 40 biopsies were obtained from 37 patients.Inmunohistochemical staining and Western blot were performed to detect the expression of VEGF protein.Reverse-transcriptase polymerase chain reaction(RT-PCR)was used to analyze the presence and quantity of VEGF mRNA.The extent of PTBE was estimated as an edema index(EI)based on preoperative magnetic resonance imaging.Results In VEGF-positive cases,a decreasing gradient of VEGF protein expression was observed with increasing distance from tumors(0.38±0.08,0.20±0.03,0.04±0.02).In meningiomas,the protein level and the mRNA level were congruent and the expression of both protein and mRNA had a significant correlation with EI(protein: r =0.892,RNA: r =0.875,P ＜ 0.05).However,in peritumoral areas,protein level were not consistent with the mRNA level.Protein results showed high correlation with EI(r =0.912,P ＜ 0.05),but mRNA almost was almost undetectable(0.06±0.02).Conclusion VEGF is impartant on PTBE.It is concluded that VEGF macromolecules are secreted by tumor tissue and enter peritumoral normal brain tissue to induce edemagenesis in meningiomas.

Intravascular mechanical thrombectomy is the first-line treatment for acute ischemic stroke caused by large vessel occlusion. Parenchymal hyperdensities are common on CT scan after mechanical thrombectomy. At present, it is generally believed that it is caused by the increase of permeability after the destruction of blood-brain barrier. The appearance of parenchymal hyperdensities not only indicates a higher risk of hemorrhagic transformation, but also indicates the possibility of occurring infarction. The identification of parenchymal hyperdensities is very important for clinical decision-making and intervention, and dual-energy CT or MRI may have advantages in this regard. Further research is needed to clarify the characteristics and significance of parenchymal hyperdensities after endovascular mechanical thrombectomy.

Malignant brain edema is one of the serious complications of acute ischemic stroke, which is not uncommon after endovascular treatment, and can significantly reduce the benefits of endovascular treatment, leading to poor outcomes and even death of patients. Therefore, early identification and timely treatment are particularly important. This article reviewed the predictive factors, prevention and treatment of malignant brain edema in patients with acute ischemic stroke who received endovascular treatment.