Objective To investigate the application value of ultrasound measurement of optic nerve sheath diameter （ONSD） in the assessment of brain death. Methods A total of 124 subjects were enrolled and divided into brain death group with 34 patients， deep coma group with 28 patients， and healthy control group with 62 individuals， and ultrasound measurement of ONSD was performed for all three groups. A Spearman correlation analysis was used to investigate the correlation of brain death with ONSD and baseline characteristics. Univariate and multivariate Logistic regression analyses were used to identify the independent predictive value of ONSD for brain death. The receiver operating characteristic （ROC） curve was plotted to determine the optimal cut-off value of ONSD and evaluate its diagnostic efficacy. Results The Spearman correlation analysis showed a significant positive correlation between brain death and ONSD （r=0.825，P<0.001）. The multivariate Logistic regression analysis confirmed that ONSD was an independent predictive factor for brain death （odds ratio=70.874， P<0.05，Nagelkerke R²=0.739， Hosmer-Lemeshow test P=0.786）.ONSD had an area under the ROC curve （AUC） of 0.939（95%CI 88.3‒99.4） in the brain death group and the deep coma group， with an optimal cut-off value of 6.005 mm， a sensitivity of 97.1%，a specificity of 78.6%， a positive predictive value of 84.6%， and a negative predictive value of 95.7%. Conclusion Ultrasound measurement of ONSD has an important clinical application value in the assessment of brain death.

Objective To investigate the features of lesions on carotid artery ultrasound in Takayasu arteritis （TA） patients with ischemic stroke （IS） as the initial symptom. Methods A retrospective analysis was performed for the clinical data， vascular ultrasound findings， and other imaging data of six TA patients with IS as the initial symptom who were treated in The First Affiliated Hospital of China Medical University from January 2016 to December 2024， and a literature review was also performed to investigate the features of lesions on carotid artery ultrasound. Results Among the six patients， there were two male patients and four female patients， with a median age of 29 years. There were four patients with an increase in erythrocyte sedimentation rate， and magnetic resonance imaging showed three cases of single-region IS and three cases of multi-region IS， with the involvement of the basal ganglia in four patients. Computed tomography angiography showed three patients with Numano type Ⅰ disease and three patients comorbid with middle cerebral artery occlusion. Among the six patients in terms of the changes on carotid artery ultrasound， four patients had significant wall thickening of the proximal common carotid artery （CCA） and intra-luminal thrombosis and occlusion on the stroke-affected side， one patient had wall thickening of the proximal CCA without detectable thrombosis， and one patient had intra-luminal thrombosis and occlusion in the CCA without detectable wall thickening； one patient had thrombotic occlusion of the proximal internal carotid artery （ICA）， one patient had thrombotic occlusion of the distal ICA， and four patients had collateral supply from the external carotid artery to the ICA via reversed flow. The assessment of lesion activity based on carotid ultrasound showed that five patients had active lesions in the CCA on the stroke-affected side， among whom two patients underwent contrast-enhanced ultrasound （CEUS） and were found to have grade Ⅲ enhancement. Carotid artery ultrasound follow-up showed that five patients achieved alleviation of CCA wall thickening， among whom two patients had a reduction from grade Ⅲ enhancement to grade Ⅰ enhancement， while one patient experienced progression from unilateral to bilateral CCA lesions and an increase to grade Ⅲ enhancement on follow-up CEUS. Conclusion TA with IS as the initial symptom mainly occurs during the active phase of the disease and demonstrates characteristic changes on carotid artery ultrasound， and conventional vascular ultrasound and CEUS may help with disease diagnosis， activity assessment， and dynamic follow-up.

Objective The supine-to-standing transcranial Doppler（TCD） technique is suitable for evaluating cardiovascular autonomic dysfunction， and this study aims to assess its performance in predicting adverse outcomes in diabetic patients with or without orthostatic hypotension （OH）. Methods The patients with type 2 diabetes mellitus who were admitted to Department of Endocrinology and Department of Neurology in The Second Affiliated Hospital of Hainan Medical University from August 2020 to May 2023 were enrolled as subjects. Basic clinical data were collected， and supine-to-standing TCD was performed to monitor and record the changes in blood pressure， heart rate， and cerebral hemodynamics in both supine and standing positions. The patients were followed for 2-4 years to record medication， orthostatic intolerance score， and adverse events. The two-independent-samples t test was used for comparison of normally distributed continuous variables between groups， and the Mann-Whitney U test was used for comparison of non-normally distributed continuous variables between groups； the chi-square test was used for comparison of categorical variables between groups. The binary logistic regression analysis was used to investigate the association between the results of supine-to-standing TCD and adverse outcomes. Results A total of 118 patients （96 male patients and 22 female patients） were enrolled， among whom there were 28 patients with OH （23.7%） and 90 patients without OH（76.3%）. During follow-up， 19 patients （16.1%） experienced adverse outcomes （including syncope， falls， and death）.TCD showed that impaired “W” wave recovery in cerebral blood flow in the standing position was an independent risk factor for adverse outcomes in diabetic patients （OR=3.536， 95% CI 1.136-11.006， P=0.029）. Conclusion Vascular reflex failure and paradoxical cerebral vasoconstriction may be the mechanisms for impaired cerebral blood flow recovery in the standing position. TCD testing has an important role in detecting cerebrovascular abnormalities and cerebral hemodynamic changes， especially in diabetic patients with OH， and it has good performance in predicting adverse outcomes.

Severe carotid artery stenosis is an independent risk factor for stroke， and carotid endarterectomy （CEA） can effectively prevent ischemic stroke by alleviating such stenosis. However， CEA carries certain risks of adverse events， including perioperative death， ischemic stroke， and hyperperfusion injury， and these adverse events not only compromise perioperative safety but also diminish the efficacy of the procedure in preventing cerebral ischemic events. A multimodal imaging-based comprehensive management mode （i.e.， preoperative assessment with carotid ultrasound， transcranial Doppler （TCD）， and CT angiography， intraoperative monitoring with TCD and cerebral oximetry， and standardized postoperative follow-up with carotid ultrasound and TCD） can significantly reduce perioperative mortality and the incidence rate of stroke and avoid hypoperfusion， hyperperfusion syndrome， and arterial restenosis or occlusion， thereby enhancing the perioperative safety of CEA.

Objective To investigate the severity of white matter lesions （WML） in patients with right-to-left shunt （RLS）-positive migraine. Methods A total of 415 patients with RLS-positive migraine who were consecutively admitted to Department of Neurology， The First Affiliated Hospital of Soochow University， from January 2022 to January 2025 were enrolled， and all these patients met the diagnostic criteria in The International Classification of Headache Disorders， 3 rd edition. RLS was diagnosed based on contrast-enhanced transcranial Doppler and contrast-enhanced transesophageal echocardiography， and the type and grade of RLS were assessed. After a series of statistical analyses was conducted， the factors with P<0.05 in the univariate logistic regression analysis were included in the multivariate binary logistic regression analysis to investigate the risk factors for the onset and severity of WML， with P<0.05 indicating statistical significance. Results The analysis of the baseline data of patients with different grades of WML showed that the grade of WML increased with age in the patients with RLS-positive migraine （P<0.05）. Comparison of multimodal ultrasound findings between the patients with different grades of WML showed that there were significant differences between the patients with different grades of WML in the factors such as large RLS， potential RLS， prolonged PFO tunnel， higher PFO at the right atrial side in resting state and after Valsalva maneuver， higher PFO at the left atrial side after Valsalva maneuver， early appearance of shunt， and longer duration of shunt （P<0.05）. For the establishment of a predictive model， large RLS shunt （P=0.037）， higher PFO at the right atrial side after Valsalva maneuver （P=0.018）， and longer duration of shunt （P<0.001） were independent risk factors for the onset of WML in patients with RLS-positive migraine， and further research showed that prolonged PFO tunnel （P<0.001） was a risk factor for the onset of moderate-to-severe WML in patients with RLS-positive migraine. Conclusion The predictive model established based on the ultrasound factors including large RLS shunt and prolonged PFO tunnel can be used as an imaging method to screen for WML， especially moderate-to-severe WML， which provides a theoretical basis for subsequent treatment.

Objective There are currently limited studies on the hemodynamics of posterior cerebral artery （PCA） compensation in patients with severe stenosis or occlusion of the internal carotid artery （ICA）， and this study aims to investigate the application value of transcranial Doppler （TCD） in assessing PCA compensation after severe stenosis or occlusion of the unilateral extracranial ICA. Methods A retrospective analysis was performed for 107 patients who were hospitalized in Encephalopathy Center， Guangdong Provincial Hospital of Traditional Chinese Medicine， from January 2022 to February 2025 and met the diagnostic criteria for severe stenosis or occlusion of the unilateral extracranial ICA， and all patients underwent both digital subtraction angiography （DSA） and TCD. The patients were divided into groups based on PCA compensation on DSA， and TCD quantitative parameters were analyzed. The receiver operating characteristic （ROC） curve was plotted to investigate the value of TCD in assessing graded compensation of the PCA. Results Among the 107 patients， there were 75 patients （70.1%） in the compensation group and 32 patients （29.9%） in the non-compensation group. The optimal cut-off value of TCD in assessing PCA compensation was a mean velocity of ≥65 cm/s at the PCA P1 segment， with an area under the ROC curve（AUC） of 0.869（95% CI 0.785‒0.953）， a sensitivity of 78.7%， a specificity of 84.4%， and a Youden index of 0.630. Compared with the non-compensation group， the compensation group had significant increases in peak systolic velocity， end-diastolic velocity， and mean velocity （P<0.01） and a significant reduction in pulsatility index （P<0.05）. As for the graded compensation of the PCA， the patients with posterior communicating artery （PCoA） compensation alone accounted for 57.3% （43/75）， those with leptomeningeal collateral compensation of the PCA alone accounted for 16.0%（12/75）， and those with both patterns of compensation accounted for 36.7% （20/75）.An end-diastolic velocity of ≥48 cm/s at the PCA P1 segment was the optimal cut-off value for assessing PCoA compensation， with an AUC of 0.813 （95%CI 0.726‒0.900）， a sensitivity of 76.2%， a specificity of 79.5%， and a Youden index of 0.557； a mean velocity of ≥60 cm/s at the PCA P2 segment was the optimal cut-off value for assessing leptomeningeal collateral compensation of the PCA， with an AUC of 0.824 （95%CI 0.723‒0.925）， a sensitivity of 71.5%， a specificity of 90.7%， and a Youden index of 0.625. Conclusion This study conducts a hemodynamic stratification analysis on compensation patterns of the PCA in patients with severe stenosis or occlusion of the unilateral extracranial ICA. Quantitative blood flow indicators at the PCA-P1 and PCA-P2 segments are highly consistent with DSA in assessing PCA compensation and can reliably evaluate the compensation status of the PCoA and the leptomeningeal collaterals.

Case-based teaching is a teaching model that integrates theoretical knowledge with clinical practice， and it is widely used in medical education and plays an important role in standardized residency training. Taking preoperative vascular ultrasound evaluation for carotid endarterectomy （CEA） as an example， this article explores the application of the case-based teaching method in cultivating clinical thinking ability among trainees receiving standardized residency training for ultrasound. Through an analysis of typical cases， trainees engage in the whole process of clinical practice under the guidance of instructors， from medical history collection and imaging interpretation to identification of key intraoperative issues. The teaching process emphasizes the characteristics of vascular ultrasound， such as the combination of vascular structure and hemodynamics， integrated cerebrovascular and cervical assessment， and precise evaluation of collateral circulation. The case-based teaching method not only deepens the understanding of diseases among trainees， but also fosters their ability to think independently and solve clinical problems， facilitating the transition from theory to practice and ensuring precise diagnosis and treatment. This article summarizes the implementation steps and effectiveness of the case-based teaching method， in order to provide a reference for ultrasound residency training.

Artificial intelligence （AI） technologies， especially machine learning algorithms， have achieved remarkable advances in medical image analysis in recent years. As a noninvasive， real-time， and cost-effective imaging modality， vascular ultrasound is one of the most active areas for the application of AI technologies in medicine. This article reviews the latest research advances in the application of AI in vascular ultrasound image recognition， automatic segmentation， diagnostic assistance， and risk prediction in 2021—2025， covering the aspects of transcranial Doppler， carotid artery， abdominal aortic aneurysms， aortic dissection， peripheral artery disease， arteriovenous fistula， venous thrombosis， and the inferior vena cava. This article highlights the key technological innovations， clinical value， and research challenges of AI within these areas.

Objective To apply bedside ultrasound for real-time monitoring of intracranial conditions in patients with severe traumatic brain injury experiencing acute encephalocele during large craniotomy， and to investigate the clinical value of intraoperative bedside ultrasound in the diagnosis and prognostic evaluation of acute encephalocele. Methods A retrospective analysis was performed for 32 adult patients with severe traumatic brain injury， and according to whether intraoperative ultrasound was performed， they were divided into ultrasound group with 17 patients and CT group with 15 patients. The two groups were compared in terms of time of operation， accuracy， mortality rate， and postoperative Glasgow Outcome Scale （GOS） score. The chi-square test was used for comparison of categorical data between groups， and the independent samples t-test was used for comparison of continuous data between groups. Results Both ultrasound and CT could provide an accurate basis for diagnosis， with no significant difference in diagnostic accuracy； however， compared with the CT group， the ultrasound group had significantly shorter time of operation and diagnostic time. Based on GOS score and grading results at 6 months after surgery， the patients undergoing ultrasound examination had a significantly better prognosis than those undergoing CT examination. Conclusion Intraoperative ultrasound for patients with severe traumatic brain injury enables rapid and accurate identification of etiology， facilitates dynamic intracranial monitoring， and shortens the time for rescue， showing an important clinical significance in improving prognosis and reducing mortality rate. Therefore， it holds promise for clinical application.