| Background and purpose:An intracranial aneurysm is an abnormal protrusion of the intracranial vascular wall caused by congenital anomaly or acquired injury.The ruptured aneurysm is the main cause of subarachnoid hemorrhage,which has a high mortality and disability rate.The death rate of patients in 30 days is as high as 45%.About 30%of survivors have varying degrees of neurological impairments.According to the literature,the detection rate of intracranial aneurysms in autopsy is 1%-5%.The epidemiological investigation of MRA in the Shanghai Sixth People’s Hospital shows that the prevalence rate of intracranial aneurysms in the domestic general population is 7%.The treatment of intracranial aneurysms includes traditional surgical craniotomy and clipping and endovascular intervention,of which the latter has developed rapidly in the past 30 years.The medium-and long-term results of the International Subarachnoid Aneurysm Trial(ISAT)show that the endovascular intervention is superior to surgical clipping in terms of mortality and disability rate and incidence rate of epilepsy.Endovascular intervention has become the preferred treatment for patients with intracranial aneurysms.Coil embolization has become the mainstream treatment for intracranial aneurysms.However,there are still some serious technical challenges to be overcome by coil embolization treatment for wide-necked intracranial aneurysms(aneurysmal neck>4 mm or aneurysmal neck:aneurysm body>1:2).For this reason,stent-assisted embolization comes into being.The use of stents can not only prevent the occurrence of thrombus events caused by the coil falling off to the parent artery,but also promote the healing of blood vessels at the aneurysmal neck,which is a good solution to the wide-necked intracranial aneurysms.Through the canine intracranial aneurysm model,Liu et al.found that the stent can induce endothelial progenitor cells to homing,and act as a "scaffold" to promote endothelial cells to cover the aneurysmal neck and promote the healing of the aneurysm.It was found that the higher the coverage rate of the stent wire at the aneurysmal neck,the faster and smoother the healing of the aneurysmal opening.In recent years,with the progress of studies on the hemodynamics of aneurysms,the concept of aneurysm treatment has changed from simple "intratumoral packing" to "vascular reconstruction" and "blood flow reconstruction" of the parent artery.The flow diverters(FD)designed for such purpose,such as Silk stents,Pipeline stents,Surpass stents,Fred stents and domestic Tubridge stents,have shown great advantages in the treatment of aneurysms by improving the hemodynamics of the aneurysmal neck to promote the repair of the parent artery and the healing of aneurysms.However,the visibility of stents by DSA has always been an issue for neural interventional physicians.Although the metal markers(NeuroFrom EZ,Enterprise,SolitaireAB,etc.)at both ends of the stent or the double-helix radiology markers(LEO,Lvis and Lvis Jr,Tubridge,etc.)can indicate the status of stent opening,due to the influence of DSA machine performance,thick skull tissue X-ray shielding and the limitation of working position angle,abnormalities such as locally incomplete stent opening or incomplete attachment during the operation are difficult to be identified for some patients.It is an important cause for thrombosis in the stent,occlusion of perforating vessels,prolonged stent intimalization and other complications.In this case,how to ensure the accurate observation and evaluation of the attachment during the operation,and then take timely targeted post-treatment,is an important issue to be addressed in the treatment with intracranial stent implantation.In recent years,with the development of imaging techniques and the improvement of DSA machines,three-dimensional fusion of two or more images such as C-arm CT plain image,especially the high-resolution C-arm CT image information developed in recent years and the 3D-DSA,CTA or MRA images of target blood vessels can be carried out in the DSA post-processing workstation,and dual-or multi-volume reconstruction technique can be used to obtain reconstructed post-processing images,which can clearly show the internal structure of lesions and proximity to surrounding tissues,thus guiding the diagnosis and treatment of cerebrovascular diseases.However,there are very few reports on the application of stent-assisted embolization of intracranial aneurysms.The purpose of this paper is to evaluate the effect of stent expansion and wall attachment by using high-resolution C-arm CT and 3D-DSA dual-volume fusion reconstruction technique,thus reducing the complications caused by poor stent attachment.Through the analysis of basic information of patients with poor stent attachment,the relevant risk factors affecting stent attachment are screened out to guide the clinical practice,improve the interventional operation,enhance the efficacy and reduce the complications.Method:From September 2018 to September 2019,the clinical and imaging data of stent-assisted coil embolization(SACE)or flow diverter(FD)for intracranial aneurysms in the First Affiliated Hospital of Zhengzhou University were analyzed retrospectively.After stent implantation,conventional digital subtraction angiography,injection of low-concentration contrast agent,high-resolution C-arm CT scanning reconstruction technique and dual-volume fusion reconstruction technique were used to evaluate and record the stent attachment.The accuracy of dual-volume fusion reconstruction technique in the evaluation of stent attachment was analyzed through pairwise comparison of different techniques using relevant statistical methods.The safety and effectiveness of this technique were evaluated by statistical analysis of perioperative complications and the DSA follow-up results of aneurysms.Through statistical analysis of factors that may affect stent attachment,the risk factors that may affect stent attachment were screened out.Results:1.A total of 172 patients were included.A total of 198 stents were used for treating 237 aneurysms.Among them,107 patients were treated with stent-assisted coil embolization for 120 aneurysms(94 unilateral aneurysms and 13 bilateral aneurysms),and 65 patients were treated with 78 multilayer stents for 117 aneurysms.52 Neuroform stents,36 Enterprise stents and 32 Lvis stents were used for stent-assisted coil embolization,and 32 Pipeline stents and 46 Tubridge stents were used as multilayer stents,with a technical success rate of 100%.2.After 198 stents were implanted,the results of stent attachment were examined.36 stents were found to be incompletely attached by conventional digital subtraction angiography technique,46 stents were found to be incompletely attached by low-concentration contrast agent reconstruction technique,and 46 stents were found to be incompletely attached by dual-volume fusion reconstruction technique.The results of layered chi-square test showed that the dual-volume fusion reconstruction technique was superior to conventional digital subtraction angiography technique in terms of clearly and correctly displaying stent attachment and there was statistical difference between the two methods(P<0.001).However,there was no statistical difference between the dual-volume fusion reconstruction technique and low-concentration contrast agent reconstruction technique(P<0.999)in terms of displaying stent attachment.Patients found intraoperatively with poor stent attachment were treated with balloon dilatation or microwire loop massage(Massage technique)and the stent attachment was significantly improved.The remaining 152 stents were proved to have complete expansion and good attachment by low-concentration contrast agent reconstruction technique and dual-volume fusion reconstruction technique.The consistency rate of the two techniques in detecting FD attachment was 100%,with an accuracy rate higher than that of conventional digital subtraction angiography technique(P<0.001)(Table 2).3.Multivariate Logistic regression analysis showed that the maximum diameter of parent artery greater than 4mm(P=0.022),the diameter difference of the parent artery at both ends of the stent greater than 0.3mm(P=0.005),the parent artery with stenosis(P<0.001),and the angle of the stent greater than 90 degrees(P<0.001)were the risk factors affecting stent attachment.Gender,age,smoking habit,hypertension,diabetes,stent implantation site,diameter of aneurysmal neck,combination with coil therapy,occlusion of branch vessels,stent diameter had no significant impact on stent attachment.Conclusion:1)High-resolution C-arm CT and 3D-DSA dual-volume fusion reconstruction technique can better display the details of intracranial stents,and accurately judge the stent expansion and attachment.2)To reduce the complications such as acute thrombosis and improve the long-term healing rate of the aneurysms and patency rate of stents,it is necessary to judge whether the stent attaches to the wall of the blood vessel and take corresponding strategies to improve the stent attachment in time.3)Multivariate regression analysis showed that the maximum diameter of parent artery>4mm,the diameter difference of the parent artery at both ends of the stent>0.3mm,the parent artery with stenosis,and the angle of the stent>90 degrees were the risk factors affecting stent attachment in stent implantation of aneurysms.4)Surgeons should be reminded to fully evaluate the preoperative risks of patients to guide the operation and prevent complications. |
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