Objective To investigate the clinical features of internal carotid steal syndrome. Methods The clinical manifestations, CT or MRI, digital subtraction angiography, and blood flow compensation in 6 patients with internal carotid steal syndrome were analyzed. Results Of the 6 patients, 2 had unilateral internal carotid artery stenosis, 4 had severe stenosis (in which 2 were on the left side, 1 was on the right side, and 1 was on both sides). The clinical manifestations of the patients with internal carotid steal syndrome were watershed infarction and transient ischemic attack. Four patients had posterior circulation ischemia and 2 had anterior circulation ischemia. Digital subtraction angiography demonstrated that collateral circulation was established in all the 6 patients. The anterior communicating artery, posterior communicating artery, and pial artery were the common compensatory vessels. Conclusions Internal carotid artery steal syndrome can be presented as anterior or posterior circulation ischemia, and the collateral circulation plays an important role in the compensation.

Objective To explore the difference of the contrast-enhanced ultrasound (CEUS) image and quantitative parameters between two different contrast agents Fluorocarbon and SonoVue. Methods The tumor model of colorectal carcinoma in nude mice was established by injecting CT26 cells into the subcutaneous space in hepatic area of 15 nude mice. CEUS was performed with Fluorocarbon and SonoVue on the 14th day after establishment. SonoLiver software was used to analyze the dynamic image quantitatively. The difference of the CEUS image and quantitative parameters between the two contrast agents was analyzed. Results Compared with normal liver parenchyma around the tumor, the tumor ultrasound contrast performance was fast forward and rewind with low enhancement. There was no signiifcant difference between the two kinds of microbubbles not only for CEUS image but also for quantitative parameters [maximum intensity (Imax):49.53%±24.38%vs 45.04%±17.03%, rise time (RT):11.68 s±3.07 s vs 13.76 s±2.92 s, time to peak (TTP):12.76 s±4.12 s vs 15.26 s±3.74 s, T1/2:50.57 s±28.32 s vs 48.75 s±9.85 s, Imax/TTP(V1):4.48±2.82 vs 3.18±1.49, (Imax-INT60)/(60-TTP)(V2):0.67±0.34 vs 0.60±0.20, AUC1:3032.78%±1343.12%vs 3258.77%±1369.84%, AUC2:11647.38%±6183.10%vs 10439.04%±4604.65%, AUC:14680.17%±7469.85%vs 13697.81%±5831.99%, Rate of AUC1:264.25±146.93 vs 222.24±92.16, Rate of AUC2:241.67±119.97 vs 231.97±100.34, all P>0.05). No mouse was dead during the CEUS examination. Conclusion Fluorocarbon had similar CEUS imaging effect and quantitative information compared with SonoVue.

Objective To investigate the significance of intravascular ultrasound (IVUS) in diagnosis and treatment of carotid stenosis.Methods IVUS was performed before and after carotid arterial stenting (CAS) in 12 patients with moderate or severe carotid stenosis,admitted to our hospital from July 2014 to April 2016 and diagnosed by digital subtraction angiography (DSA).The severity of carotid stenosis,expansion and adherence of the stent were observed,respectively.Results DSA indicated 17 vessels having pathological changes,including 4 (23.5％) eccentric lesions and 13 (76.5％) concentric lesions;IVUS indicated 23 vessels having pathological changes,including 13 (56.5％) eccentric lesions and 10 (43.5％) concentric lesions;the rate of eccentric plaque detected by IVUS was significantly higher than that by DSA (P＜0.05).The carotid diameter stenosis degree measured by DSA was smaller than the stenosis degree by IVUS (P＜0.05).In 4 patients underwent CAS,DSA showed that the residual stenosis was more than 30％,and IVUS showed stent underexpansion or poor adherence;in other 5 patients undewent CAS,IVUS showed poor stent symmetry,however,IVUS showed that the stent expansion,symmetry and adherence became better after the balloon expansion.Conclusion IVUS is useful for evaluation before and after stenting in patients with moderate or severe carotid stenosis.

Objective To observe the correlation between degrees ofextracranial cerebral artery stenosis and pressure ratio across stenosis.Methods The patients with ≥ 50％ stenosis,admitted to our hospital and conformed by DSA from September 2015 to February 2017,were collected in this study.Collateral circulation compensation was assessed by DSA.The distal stenosis pressure (Pd) and stenosis pressure (Pa) were measured by pressure wire system;the pressure ratio across stenosis was recorded.Correlations of pressure ratio with stenosis rate and collateral circulation compensation were analyzed by Spearman correlation.Results Thirty one stenotic extracranial cerebral arteries (9 of carotid stenosis,12 of vertebral artery stenosis and 10 of subclavian artery stenosis) in 28 patients were collected.There were no perioperative complications or adverse events.The vascular stenosis rate showed negative correlation with pressure ratio (r=-0.615,P=0.000).In the subgroups,pressure gradient was negatively correlated with carotid artery stenosis rate (r=-0.948,P=-0.000),vertebral artery stenosis rate (r=-0.757,P=0.004) and subclavian artery stenosis (r=-0.759,P=0.011).Pressure ratio and collateral circulation compensation showed negative correlated relation (r=-0.475,P=0.007).Conclusion The pressure ratio across stenosis gets worse impairment with increase of severity of stenosis,and the collateral circulation influences the pressure ratio.

Objective To study the effect of stenting on intravascular pressure difference at both ends of stenosis in patients with symptomatic internal carotid artery stenosis (CAS).Methods Eleven patients with moderate-severe internal CAS were included in this study.Their distal mean arterial pressure was measured by pushing the pressure guide wire into the distal end of stenosis and the proximal mean arterial pressure was measured by placing the pressure receptor connecting pipe into the proximal end of stenosis.The intravascular pressure difference at both ends of stenosis was calculated.Correlation between the stenosis rate and intravascular pressure difference at both ends of stenosis was analyzed by Spearman correlation analysis.The intravascular pressure difference before and after stenting was analyzed according to the Wicoxon test.Results Complete intravascular pressure difference value was detected in 11 CAS patients before and after operation.No complications and adverse events occurred during the perioperative period.The stenosis rate was 64％-95％ (74.18％±8.70％) and 0％30％ (12.64％±11.07％) respectively before and after operation.The intravascular pressure was 5-72 (15.64±19.64) mm Hg before operation and was 0-9 (2.64±2.69) mm Hg after operation (P=0.035,P=0.000).Spearman correlation analysis showed that the stenosis rate was positively related with the intravascular pressure difference (r=0.767,P＜0.01).Conclusion Carotid artery stenting can reduce both the stenosis rate and intravascular pressure difference at both ends of stenosis.