Objective To investigate the effect of intravenous ultrafine superparamagnetic iron oxide nanoparticles feraheme (generic name:ferumoxytol) on cerebral infarction volume and inflammatory response in mice with permanent middle cerebral artery occlusion.Methods Thirty C57BL/6J mice were divided into sham operation group,saline control group,and feraheme group by the random number table (n =10 in each group).A permanent right middle cerebral artery occlusion model was induced by the modified suture method in the saline control group and the feraheme group,and no suture was inserted into the mice of the sham operation group.The intervention was performed by tail vein injection at 24 h after modeling.The sham operation group and the feraheme group were injected with 18 mg/kg feraheme,and the saline control group was injected with the same volume of normal saline.The neurobehavioral scores were conducted at 24 h (before the feraheme or saline injection) and 48 h (before the MRI exam) after modeling.MRI scans were performed at 48 h after modeling,and the cerebral infarction volume was calculated according to T2-weighted imaging.After the end of the scan,orbital blood was collected for the detection of serum tumor necrosis factor (TNF)-α,interleukin (IL)-1 β,and IL-6 levels.Then,the mice were sacrificed and the brain tissue was taken for HE staining and Ibal immunohistochemical staining.Results There were no significant differences in the infarct volume and neurological function score between the saline control group and the feraheme group.The serum levels of TNF-α,IL-1β,and IL-6 in the saline control group and the feraheme group were significantly higher than those in the sham operation group (P ＜0.05),but there was no significant difference between the saline control group and the feraheme group.Conclusion Intravenous injection of 18 mg/kg feraheme at 24 h after cerebral ischemia did not affect the infarct volume and inflammatory response,suggesting that this dose of feraheme can be used for molecular imaging studies of inflammatory response after cerebral ischemia.

To investigate the clinical value of transcranial Doppler ultrasound （TCD） in evaluating intracranial collateral circulation in patients with extracranial segment of unilateral internal carotid artery occlusion （ICAO）. Methods A total of 145 patients with ICAO，109 in the symptomatic group and 36 in the asymptomatic group，who were diagnosed by cervical vascular ultrasonography and confirmed by digital subtraction angiography （DSA） in the Stroke Center of the First Affiliated Hospital of Soochow University from January 2018 to December 2020，were retrospectively enrolled. TCD was recorded to evaluate intracranial collateral circulation types and performed consistency test with DSA.The hemodynamic parameters of bilateral middle cerebral artery （MCA） and CT perfusion （CTP） parameters of bilateral basal ganglia and temporal lobe were recorded. According to the Collateral circulation assessment system of the American Society for Interventional and Therapeutic Neuroradiology/Society for Interventional Radiology （ASITN/SIR），patients were divided into poor collateral circulation（grade 0～2） and good collateral circulation （grade 3～4），and the differences of MCA parameters and CTP parameters were compared between the two groups. The differences in bilateral MCA blood flow parameters between the asymptomatic group and the symptomatic group and the early CT scores （ASPECTS） of the Alberta Stroke Project were compared.Results （1） Consistency analysis：The coincidence rates of anterior communicating artery （ACoA），posterior communicating artery （PCoA），ocular artery （OA） and DSA evaluated by TCD were：93.1%，91.0%，80.7%，with good consistency （Kappa value=0.84，0.78，0.66，all P<0.05）.（2）Collateral circulation compensation：The mean flow rate（Vm），peak systolic flow rate （Vs），end diastolic flow rate （Vd） and pulsation index （PI）of the affected middle cerebral artery in the poor collateral circulation group were lower than those in the good group，and the differences in Vm，Vs and Vd were statistically significant （P<0.05）. CBF and CBV in basal ganglia and temporal lobe were decreased，while MTT and TTP were prolonged，with statistically significant differences（all P<0.05）.（3）ASPECTS in asymptomatic group were significantly higher than those in symptomatic group，and blood flow parameters in MCA of healthy side were less different than those in symptomatic group （all P<0.01）.Conclusion TCD is consistent with DSA in evaluating intracranial collateral circulation in patients with intracranial extracranial occlusion of unilateral internal carotid artery.MCA blood flow parameters can reflect the perfusion in the blood supply area，and TCD is an effective tool for evaluating intracranial collateral circulation.