Objective To evaluate the safety、feasibility and the long-term effectiveness of polyurethane stent placement for treatment of nasolacrimal duct obstruction. Methods Fifty-three cases (64 eyes) with complete nasolacrimal duct obstruction received the lacrimal stent placement. Dacryocystography was performed before and after the procedure. The average follow-up period was 48.3 months (range, 13-78months), the long-term patency and the effectiveness after stents removal were analyzed. Results Stent placement was technically successful in 62eyes, and the success rate was 96.9% with no severe complications. On long-term follow up, the stent patency rate was 76.8% at 1 year. However, it decreased to 33.3% at 3 years and 28.6% at 5 years. Nine stents were removed when the symptoms recurred, including granulation tissue in 4 stents and mucous material in 5. After removal, 2 nasolacrimal ducts were patent, and 2 kept patent after stents replacement, but all reoccluded within 6 months. Conclusions Interventional placement of polyurethane stent in the obstructed nasolacrimal duct is a simple and safe outpatient procedure, but the long-term patency is not encouraging, and the right stent removal time has not yet been approved.

Objective To evaluate the feasibility and safety of establishing benign proliferative esophageal stenosis model by using stent implantation in experimental rats.Methods A customized self-expanding,metallic and straight tubular stent was used in this experiment (5 mm in diameter and 15 mm in length),on both sides at the stent's middle part there was a protruding barb that was used as a fixation device.Twelve healthy Sprague Dawley (SD) rats were randomized divided into group A (blank control group) and group B (stent implantation group),with 6 rats in each group.Esophageal stent implantation was employed in the rats of group B,and esophageal radiography was separately performed immediately,one and 4 weeks after stent implantation.All the experimental rats were sacrificed 4 weeks after stent implantation.The normal esophageal tissue of the rats in group A and the esophageal tissue at stent site of the rats in group B were collected and sent for pathological examinations,including gross morphology,light microscopy,etc.Results Successful stent implantation was achieved in all rats of group B,and the esophageal radiography performed immediately,one and 4 weeks after stent implantation showed no esophageal stent displacement;no severe complications occurred during the operation or follow-up period.Compared with group A,esophageal radiography reexamination performed 4 weeks after stent implantation in group B revealed that esophageal stricture at stent segment,caused by benign tissue hyperplasia,could be observed.The esophageal stent segment was taken out,its lumen was obviously narrowed under gross observation,and typical benign hyperplasia could be seen under optical microscope examination.Conclusion Using esophageal stent implantation to establish esophageal stenosis model is safe and feasible in experimental rats.The use of esophageal stent with barbs can significantly reduce the incidence of stent displacement.

Objective To evaluate the safety of a self-made vena cava stent-filter(VCSF)for prevention of pulmonary embolism.Methods Fusiform unmbrella-like vena cava filter was made of Nitinol wires and stainless steel metal pole,and then ten mongrel dogs were implanted with these self-made filters and divided into 5 groups according to the different periods(2,3,4,5 and 6 w) of filter placement,with 2 dogs in each group.After the VCSFs were placed in inferior vena cava via the right femoral vein approach,the dogs in each group were bred for 2-6 weeks,respectively.The blood flow of inferior vena cava and the position of the filters were inspected by inferior vena-cavography according to the indwelling periods.Finally the metal pole was retrieved via the femoral vein,leaving the VCSF as permanent venous stent.The feasibility of retrieval and the free state of filter net with the adhering vascular wall were evaluated.Laparotomies were performed to remove the inferior vena cava from the animals for gross and electron microscopic examinations of the inferior vena cava intimal changes of the involved segment.Results All 10 VCSFs were placed at the right positions of the dogs successfully.Angiography showed patent inferior vena cava without filter thrombosis at 2-6 weeks.There were no tilting and migration of the filter and all the metal poles were successfully retrieved.The superior and inferior extremities of filter nets could be set free with all the filters turning into venous stents.Postmortem displayed retroperitoneal hemorrhage and caval thrombosis.The barbs of the filters penetrated over the caval adventitial coat.Under electron microscope,a thin layer of neointima already covered the braiding net of VCSFs at 2 weeks after the deployment.The tunica intima became slightly thick at 3-4 weeks and with moderate proliferation at 5-6 weeks.Conclusions The self-made vena cava stent-filter possesses rather long indwelling period according to the necessity of treatment with simultaneously keeping patent caval flow,stability of the position and easy for displacement and retrieval.

Objective To investigate the suitable injection rate and dose in multi-slice CT perfusion imaging.Methods Randomized block design was adopted in this study.The treatment factor-contrast medium injection rate was classified into 3,4,5,6 and 8 ml/s;thesubjects were divided into 5 blocks grouped by contrast medium injection dose: 0.5,0.75,1,1.25 and 1.5 ml/kg.25 Beagles wererandomly enrolled to undergo cerebral CT perfusion imaging.After post processing,time to peak(TTP) and rise value(RV) were measured in superior sagital venous.Results Injection rate had a significant effect on TTP of superior sagital venous.There was no significant difference among group 5,6 and 8 ml/s.Compared with 8 ml/s,TTP of superior sagital venous was prolonged when injection rate 3,4 ml/swere adopted.Injection dose had a significant effect on RV of superior sagital venous.There was no significant difference among group 1,1.25 and 1.5 ml/kg.In comparison with 1 ml/kg,RV of superior sagital venous was prolonged when injection dose 0.5 and 0.75 ml/kg were adopted.Conclusion The quality of cerebral CT perfusion imaging is well enough even injection rate as low as 5 ml/s or injection dose as few as 1 ml/kg.

Objective To establish the rabbit model of main portal vein VX2 tumor thrombus by using orthotopic implantation and to observe its radiological and pathological features.Methods 24 New Zealand white rabbits were randomly divided into study group (n=16) and control group (n=8).In study group,VX2 tumor tissue fragments were fixed on the inner wall of the main portal vein by using a surgical approach.In control group, autologous muscle fragments were fixed on the inner wall of the main portal vein in the same way.CT examinations were performed in both group on 7 days, 14 days, 21 days and 28 days after the procedure.At each observation point,3 rabbits of the study group were inspected by using digital subtraction angiography (DSA),and then sacrificed for histologic examination.Meanwhile,1 rabbit of the control group was sacrificed for histologic examination after CT scanning.The survival time of the remaining rabbits were recorded.Results Among 16 rabbits of the study group, successful implantations were achieved in 15 rabbits (93.8%).Tumor thrombus formed in the main portal vein successfully for all these 15 rabbits.The mean survival time of the remaining 3 rabbits in the study group was (39.3±2.1) days.The imaging characteristic of tumor thrombus could be demonstrated by CT and DSA examinations.Tumor thrombus and the inner neovascularization were confirmed by histological examination.Conclusion It is feasible to establish an animal model of main portal vein tumor thrombus by orthotopic implantation.The radiological and pathological features of animal model are similar to hepatocellular carcinoma patients with portal vein tumor thrombus.

Objective To evaluate the clinical application of embolization therapy using N-butyl 2-cyanoacrylate(NBCA)for hepatocellular carcinoma(HCC)complicated with arterio-portal fistula(APF).Methods Eighty patients with HCC and APF underwent embolothempy with NBCA(NBCA group,26 patients)or absolute alcohol(alcohol group,54 patients).The APF wag first treated with liquid embolic agent during the TACE procedure.We used NBCA-Lipiodol mixtures in concentration of 20%-50% according to tlle different circulation times of these APF in NBCA group,Absolute alcohol plus gelfoam or other materisis were used for embolization of APF in alcohol group.The pain reaction during the procedure,influence for liver function(X2 test).occlusive suceessfxil rate after single embolization(Fisher's exact test)and the survival rate of 1 year(log-rank analysis)between two groups were compared after the embolotherapy.Results Four patients in NBCA group and 52 patients in alcohol group felt painful during the pmcedures.There wag statistically significant difference between two groups(x2=58.86,P＜0.001).The APF disappeared after only sin~e embolization in 24(92.3%,24/26)cages of NBCA group and in 37(68.5%,37/54)patients of alcohol group.There wag also significant difference between two groups (P=0.024).There were no statistical ditierence in the post.embolization liver function change and 1 year survival rate between two groups.Conclusions The embolization therapy using NBCA for HCC complicated with APF is safe.effective and more accurate.It can be used as a new technique for these patients.

Objective To discuss the technique of Neuroform stent-assisted coil embolization for the treatment of intracranial wide-necked aneurysms and to evaluate its clinical efficacy and complications.Methods Neuroform stent-assisted technique was used for coil embolization treatment in 31 patients with intracranial wide-necked aneurysms, all aneurysms were ruptured and the patients suffered from subarachnoid hemorrhage (SAH). Of the total 43 aneurysms, 39 were wide-necked and 4 were narrow-necked. Results Thirty-five stents were inserted in 31 patients. The stents were implanted in both internal carotid arteries in 3 patients and in both middle cerebral arteries in one patient, Intra-arterial embolization with coils was successfully performed in 41 of 43 aneurysms. Intraoperative hemorrhage occurred in 2 patients, which probably resulted from the rupture of middle cerebral artery branch due to microwire damage. The cerebral isehemic symptom happened in 1 patient with posterior communicating artery aneurysm due to the shifting of the coil from the original site to M2 segment of middle cerebral artery. During a follow-up period of 24.7 months in average, neither death nor recurrent hemorrhage occurred in 29 cases. Twenty-eight patients were in good living condition and the remaining one patient showed obvious disturbance of neural function.Conclusion For the treatment of intracranial wide-necked aneurysms, intra-arterial coil embolization with Neuroform stent-assisted technique is a safe and effective clinical therapy. It can effectively broaden the extent of indications in treating intracranial aneurysms by using interventional technique.

Objective To investigate the feasibility, safety and efficacy of transarterial embolization with low concentration of n-butyl cyanoacrylate(NBCA) in rabbit VX2 liver tumor models. MethodsTwenty-four rabbits were implanted with VX2 hepatic tumors into the left hepatic lobes, and were scanned with CT to measure the volume of the tumor after 14 days. They were randomly divided into three groups with 8 rabbits assigned to each group. Transarterial embolization was conducted with physiological saline in control group A, with pure Lipiodol in group B, with 2.5% NBCA in group C. Hepatic toxicity was evaluated by blood biochemical analysis of the plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST). One week later, the volumes of the tumors were measured by CT again. Tumor growth rate was the ratio of tumor's volume at 7th day after embolization to the tumors' volume before embolization. The survival periods of the rabbits of the three groups after treatment were also recorded. The data of ALT and AST mean values from each group were analyzed with repeated measurement analysis of variance (ANOVA). Tumor growth rates and survival periods were analyzed by using one-way ANOVA. Results All animal models were successfully established and underwent interventional catheterization. Both ALT and AST mean values of the rabbits in group A, B and C at each time point before and after embolization were significantly different (ALT F=10.508, 16.443, 19.828, respectively; AST F=23.696, 23.334, 15.594, respectively)(P＜0.05). ALT in group A, B, C were (49.4±13.5), (115.2±48.8), (124.7±49.4)U/L, while AST in group A, B, C were (52.3±12.0), (128.3±50.1), (137.0±66.9)U/L 4 days after embolization. The ALT and AST mean values were significantly elevated 4 days after embolization in group B and group C compared with those before embolization and those of group A 4 days after treatment(P＜0.05). However, the ALT and AST mean values showed no statistically significant difference in all the groups before embolization and 7 days after embolization. On the other hand, the growth rates of the tumors differed significantly among the three groups(F=110.865, P=0.000). The group C showed significantly lower tumor growth rate (0.839±0.144)% than the group A(2.978±0.547)%(P=0.000), but no significantly different tumor growth rate compared with group B(0.871±0.0725)%( P=0.845). Consequently, the survival period of the animals in group C(38.9±4.0) days was significantly longer than that in group A(32.1±3.1)days (P=0.006), while it was not significantly different from that in group B(36.9±4.8)days(P=0.366). ConclusionsTransarterial embolization with low concentration of NBCA was feasible and safe. It could be a new option of treatment for HCC and might have potential further clinical value.

Objective To discuss the safety,efficacy and time window of thombolysis using recombinant staphylokinase(r-Sak).Methods The model of acute cerebral infarction was established with interventional embolization technique in 24 adult beagle dogs,which were randomly divided into 3 groups including control group,6 h intra-arterial group and 3 h intravenous group.Angiography was performed before thrombolysis.We administered r-Sak for thrombolysis(10 ml of saline in control group,0.2 mg/kg of r-Sak in the intra-arterial group through left internal carotid artery 6 h after embolization,and 0.2 mg/kg of r-Sak in the intravenous group through femoral vein 3 h after embolization).Follow-up angiography was repeated half,1 and 2 hours after thrombolysis.The plasma levels of PT,APTT and D-dimer were assayed at the time points of 30 min before thrombolysis,30 min,60 min and 120 min after thrombolysis.These canines were sacrificed,and their brains were taken out for pathological study at 24 hours after embolization.Results The recanaled vessels at 2 hours after thrombolysis was 11(11/13) in the intra-arterial group,8(8/11) in r-Sak intravenous group and 1(1/10) in control group,and the vessels of complete recanalization was 6(6/13),2(2/11) and 0(0/10),respectively.There were statistically significant differences among the three groups (P=0.001 and P=0.035 respectively),but there were no statistically significant differences between the intra-arterial and the intravenous groups (P=0.630 and P=0.211).The PT and APTT are significantly prolonged in the thrombolytic groups.The levels of D-dimer was not changed after thrombolysis (P＞0.05). All dogs were alive 24 h ours after embolization.The clinical presentations in the thrombolytic groups were better.Pathologically,there were no cerebral hemorrhage in all groups.Conclusion r-Sak has strong effect of thrombolysis,and its complication of intracerebral hemorrhage is rare.The intra-arterial thrombolysis 6 h after embolization using r-Sak is safe and effective.

Objective To establish an easily reproducible rabbit model of acute pulmonary embolism (APE) with right ventricular dysfunction (RVD).Methods Two gelfoam strips (5 rnm×5 mm× 10 mm) were squeezed and were introduced into the pulmonary arteries of each healthy rabbit (n=12).Pulmonary and systemic hemodynamic function were recorded.All rabbits underwent CT pulmonary angiography (CTPA) and pathological examination after the introduction of APE.Results All gelfoam strips located in the bilateral lower lobe arteries.Compared with baseline mean pulmonary artery pressure (mPAP) ([9.75±1.75] mmHg),mPAP increased to (20.58 ± 5.86) mmHg immediately after embolism (P ＜ 0.001),and then decreased to (18.78 ±4.80) mmHg 1 h after embolism (P＜0.001).Right ventricle/left ventricle diameter ratio (RV/LV) increased from baseline (0.67±0.09) to (1.90±0.28) 45 min after embolism (P＜0.001).Conclusion An easily reproducible rabbit model of APE with RVD are established and may be suitable for study of APE pathophysiology.