Interventional radiology is a new and developing subject, and a good grasp of imaging knowledge, skilled manipulation and plenty of clinical experience are essential for physicians who are engaged in this special field. For this reason, all interventional physicians should make great efforts to unceasingly improve their theoretical levels and practical abilities. Many interventional physicians who used to be the diagnostic radiologists have solid foundation of medical imaging as well as rich manipulation ability.Nevertheless, what they usually lack is the special clinical knowledge, they are short of relevant clinical ability to confidently deal with the interventional perioperative events. The interventional perioperative performance is an important component of interventional therapy. Standard interventional preoperative preparations can effectively reduce the occurrence of postoperative complications and scientific postoperative managements will help obtain an optimal result.

Objective To investigate the CT and MRI findings of solid-cystic papillary epithelial neoplasm of pancreas, and to improve the diagnosis ability of the disease. Methods CT was performed in all 3 patients with solid-cystic papillary epithelial neoplasm of pancreas proved surgically and pathologically. Of all 3 patients, plain and dynamic enhanced MRI was performed in 1 patient. Both clinical characteristics and CT and MRI findings were analyzed retrospectively. Results All 3 patients were young female without jaundice and were found to have giant solid-cystic mass in the head of pancreas. In 1 of 3 patients, calcification was found in the mass on CT scan. One patient was found to have mild pancreatic duct dilation. No intrahepatic and extrahepatic bile duct dilation was showed in 3 patients. MRI findings in one patient demonstrated mixed signal intensity on T 1WI and T 2WI. On enhanced CT and MRI, the wall of cyst and solid portions of the mass showed obvious enhancement. Conclusion CT and MRI findings of solid-cystic papillary epithelial neoplasm of pancreas are characteristic, and the disease can be preoperatively diagnosed combined with the clinical feature.

Objective To establish carotid artery bifurcation aneurysm in canine, and to clarify whether specific hemodynamic insult in combination with arterial wall degeneration will lead to the occurrence and development of aneurysms. Methods New bifurcation aneurysm model of common carotid artery (CCA) was successfully established in 18 dogs, which were randomly divided into the elastase-treated bifurcation group (EBG,n=9) and the control bifurcation group (CBG,n=9). Three dogs were treated with elastase insult to both straight sections of CCA and were used as elastase-treated straight section group (ESG,n=3). Angiographic and hemodynamic analysis was conducted immediately after the operation, as well as 12 and 24 weeks after the operation. Histopathological examination was performed 12 and 24 weeks after the operation. Results Angiography showed that new aneurysm (mean diameter 3.2 ±0.4 mm) was formed at the apex of CCA bifurcation in 5 dog models of EBG group, while no new aneurysm was observed in both CBG and ESG groups. In EBG group, no rupture of the new aneurysm occurred during the follow-up period. Histological analysis revealed that in EBG group the inner elastic lamina was discontinued, the elastic fiber was disrupted, the muscle layer became thinned, the smooth muscle cells were reduced, and the inflammatory cell (macrophage) infiltration as well as the expressions of MMP-2 and MMP-9 were increased;these changes were statistically significant when compared with those in CBG group and ESG group (P<0.001). Postoperative hemodynamic analysis indicated that in EBG group the wall shear stress at the apex of CCA bifurcation was reduced, the blood flow velocity was decreased, with the relative and total pressure being the highest;all the above changes returned to normal after arterial wall remodeling. Conclusion The results of this study indicate that the arterial wall degeneration and the hemodynamic effect at the apex of CCA bifurcation can lead to new aneurysm formation in canine model.

Objective To investigate the technique of transarterial embolization of dural carotidcavernous fistulas(DCCFs)with low concentration(14%-25%)of n-butyl-cyanoacrylate(NBCA)and determine its value.Methods Eight patients with DCCFs were treated by transarterial embolization with low concentration of NBCA using a wedged microcatheter.Of the 8 patients,5 had unsuccessful transvenous embolization and 3 could not be treated with transvenous embolization.Results Transarterial embolization with low concentration of NBCA using a wedged microcatheter resulted in complete obliteration of the affected cavernous sinus and related shunts in 5 patients,no residual arteriovenous shunt was demonstrated on postembolization angiography.On clinical and angiographic follow-up 6-12 months later,complete resolution of clinical symptoms was observed in all 5 patients and there were no recurrent or residual DCCFs found.Partial obliteration of the involved cavernous sinus and the related shunt was achieved in the remaining 3 patients on immediate post-procedure angiography,but the volume of shunt diminished significantly.On clinical and angiographic follow-up 3 months later,in 2 patients,clinical symptoms were improved and the arteriovenous shunts were diminished;in the third patient,clinical symptom resolved and the shunt was obliterated.There were no major complications except for the transient worsening of ocular symptoms due to Ⅵ cranial nerve palsy in 1 patient.Conclusions Transarterial embolization of DCCFs with low concentration of NBCA using a wedged microcatheter was a safe and effective treatment method.It is an optimal alternative for the patients with DCCFs in which transvenous route was unsuccessful,or impossible.

Objective To establish a carotid siphon aneurysm model in dogs in order to test the mechanical features of a newly-designed Willis covered stent-graft and to investigate the histological reaction of the stent-implanted vessel during a follow-up period of 12 months.Methods Twenty-four saccular sidewall aneurysms were surgically created in twelve dogs(group A)and 12 carotid siphon aneurysms in another twelve dogs(group B).A Willis stent-graft was implanted in each aneurysm.Angiography was performed immediately after the procedure and 1,3,6 and 12 months after the implantation to investigate the aneurysm isolation,endoleak,stent angulation,and the patency or restenosis of the parent artery.Light and scanning electronic microscopy were used to identify aneurysmai sac thrombi,intima hyperplasia and endothelial progress of the stent-loaded arterial segment.Results In group B,postoperative immediate angiography demonstrated that two aneurysms had mild endoleak and three stents became angulated.Follow-up exam 12 months after the procedure revealed that all previous endoleaks disappeared,one parent artery became occluded and three parent arteries developed mild stenosis(＜50%).In group A.occlusion of parent artery was seen in one and mild stenosis(＜50%)in 2 cases.Electronic microscopy revealed new intima formation in all stents,and all aneurysmal sacs were filled with thrombi.In group B.the endothelialization process was not completed until 12 months after the stent implantation,and a marked correlation existed between endothelial cell arrangement and the hemodynamic orientation.Conclusion It is feasible to treat carotid-siphon aneurysm in dog with a Willis stent-graft.The complete endothelialization of the covered stent in tortuous vessel takes longer time than that in rather straight vessel.

Objective Complicated aneurysms located in the cisternal segment of the internal carotid artery(ICA-CSA)present unique therapeutic difficulties.This study is to discuss the feasibility of the Willis stent-graft in treating complicated ICA-CSA by comparing its effect with that of coiling therapy.Methods Willis covered stents were employed in 19 complicated ICA-CSAs(group A),while coils were used in 17 complicated ICA-CSAs(group B).Follow-up angiography was performed to investigate aneurysm recurrence,endoleak and parent artery(PA)stenosis.Kaplan-Meier curves were constructed to compare the recurrencefree and PA stenosis-free rate in both groups.Results Total exclusion was immediately achieved in 13 ICACSAs and minor endoleaks presented in 5 cases in group A.Total or near-total occlusion was achieved in 7 ICA-CSAs.subtotal occlusion in 8 and partial occlusion in 2 cases in group B after coiling.Acute thrombosis occurred in 1 patient in either group and re-hemorrhage happened in 1 patient after coiling.Follow-up angiography in group A revealed that 16 ICA-CSAs were completely isolated,with two parent arteries showing mild in-stent stenosis.Eighteen months after the procedure,Kaplan-Meier analysis showed that the recurrence-free rate was 93.3%and 50%,while the stenosis-free rate of parent artery was 87.5%and 100% in group A and in Group B,respectively.In group A and group B the clinical neurological symptoms were fully recovered in 9 and 9,obviously improved in 3 and 5,unchanged in 2 and 2,and aggravated in one and 0 patients,respectively.Conclusion The implantation of Willis stent-graft is a feasible endovascular therapy for complicated ICA-CSAs.When the parent artery is very tortuous or when the risk that a main collateral branch may be wrongly covered and occluded is present,the implantation of Willis covered stent can not be taken as the treatment of first choice.

Objective To evaluate the efficacy and mid-term follow-up results of endovascular treatment with Willis covered stent for traumatic pseudoaneurysms located in the internal carotid artery (ICA).Methods ICA angiogmphy was performed in 38 patients with traumatic brain and neck injury.Of the 38 patients.13 delayed traumatic pseudoaneurysms were found.All the pseudoaneurysms were treated with Willis covered stents.Follow-up angiography was performed at 1,3,6 and 12 months after the procedure,and the results were categorized as complete or incomplete occlusion.Clinical manifestations were graded as full recovery,improvement,unchanged and aggravation.Results Willis covered stent placement was technically successful in all traumatic pseudoaneurysms.No procedure-related complications occurred.The initial angiographic results showed a complete occlusion in 9 patients,and an incomplete occlusion in 4.The angiographic follow-up within 3-12 months exhibited a complete occlusion in 12 patients and the parent arteries remained patency in all patients.The clinical follow-up observation demonstrated that full recovery wag obtained in 11 patients,clinical improvement in one,and unchanged condition in one.No morbidity or mortality occurred.Conclusion Willis covered stent implantation iS a feasible and practical treatment for traumatic pseudoaneurysms located in the ICA.This technique can well preserve the parent artery with excellent therapeutic results.

Objective To evaluate the flexibility and efficacy of the Willis covered stent in the treatment of distal internal carotid artery(DICA)aneurysms.Methods The study was approved by the anthors' institutional review board,and the research was conducted by the authors' institution and the MicroPort Medical Company(Shanghai,China).Thirty-one patients with 33 DICA aneurysms were considered for treatment with a Willis covered stent.The angiographic assessments were categorized as complete or incomplete occlusion.The data on technical Success,initial and final angiographic results,mortality,morbidity,and final clinical outcome were collected,and follow-up was performed at 1,3,6,and 12 months and yearly after the procedures.Results Navigation and deployment of the covered stents were succssfnl in 97.6%(41 of 42;95%confidence interval[CI]:93%,102%)of the attempted stent placement procedures.The initial angiographic results showed a complete occlusion in 23 patients with 25 aneurysms(of 32 aneurysms,78.1%[95%CI:63%,93%])and an incomplete occlusion in seven patients with seven aneurysms(21.9%).The angiographic follow-up(mean,14 months[95% CI:12,15 months])findings exhibited a complete occlusion in 27 patients with 29 aneurysms(of 31 aneurysms,93.5%[95%CI:84%,103%])and an incomplete occlusion in two aneurysms(6.5%),with a mild in-stent stenosis in two patients.The clinical follow-up(mean,27 months[95% CI:23,30 months])demonstrated that 15 patients experienced a full recovery and 14 patients improved.Conclusion The preliminary results demonstrate good flexibility and efficacy of the Willis covered stent in the treatment of DICA aneurysms in selected patients:longer follow-up and expanded clinical trials are needed.

Objective The aim of the experiment is to make an intracranial aneurysm model in canine.Methods A digital tube was made based on raw magnetic resonance images of the human intracraaial carotid artery.Then 6 tubes were made in the 3 D rapid prototyping machine and coated with silicone.Finally we isolated the common carotid arteries of 6 canines and made them go through the tubes and anastomosed them end-to-side to get the aneurysm model.Six stents were implanted after one week.Results Six aneurysm models were successfully made in canines.The parent artery had similar geometrv of the human carotid siphon.All the aneurysms and parent arteries were patent in one week's follow-up.One canine died of excessive anesthesia after stentingr Two vaseular models kept patent in one month without stenosis.The other 3 had some stenosis on the bends of the vessel.Conclusions The aneurysm model in tIle experiment has high flexibility and reliability.The model provides an effective tool for research and testing neurovascular devices.It's also a useful device to train the neuroradiologists and interventional physicians.

Objective To investigate the diagnostic accuracy of contrast-free three dimensional time-of-flight (3D-TOF-MRA) with VR at 3.0 T in the detection of intracranial aneurysms in a large cohort of patients prospectively.Methods Four hundred and eleven patients with suspected aneurysms and other cerebral vascular diseases received contrast-free 3D-TOF-MRA examinations at 3.0 T MRA 2 weeks prior to DSA examination.2D-DSA and VR-DSA were regarded as the gold standard.Six patients were excluded because of motion artifacts,and 36 patients were excluded due to lack of VR-DSA data.Accuracy,sensitivity an specificity in detecting intracranial aneurysms were determined by patient-,aneurysm-,and aneurysm sizebased (＜ 3 mm,3-5 mm,＞ 5-10 mm,＞ 10 mm) evaluations.Results In 369 enrolled patients,VR-DSA revealed 306 aneurysms in 246 patients (66.7％) and no aneurysm in 123 patients; VR 3D-TOF-MRA revealed 311 aneurysms in 249 patients and no aneurysm in 120 patients.The patient-based evaluation of VR 3 D-TOF-MRA at 3.0T yielded accuracy of 97.6％ (360/369),sensitivity of 99.2％ (242/244),and specificity of 94.4％ (118/125) in the detection of intracranial aneurysms.The aneurysm-based evaluation yielded accuracy of 98.3％ (524/533),sensitivity of 99.3％ (304/306),and specificity of 96.1％(220/229).The evaluation based on aneurysm sizes (＜ 3 mm) yielded accuracy of 96.4％ (214/222),sensitivity of 98.2％ (112/114),and specificity of 94.4％ (102/108).Conclusion VR 3D-TOF-MRA at 3.0 T MR can detect intracranial aneurysms accurately and may replace DSA as a contrast-free,noninvasive and non-radiation-based modality for the diagnosis and screening of intracranial aneurysms.