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Tumor emboli due to a sarcoma are usually confirmed by an autopsy or operative findings. A sarcoma embolus in an acute stroke patient is rare. We herein report a 37-year-old man with acute stroke caused by internal carotid artery occlusion who underwent embolectomy. A histopathological analysis of an embolus obtained with a mechanical retriever device was diagnosed as undifferentiated sarcoma. This is the first case of extracardiac sarcoma extraction via mechanical retrieval performed during intervention for acute ischemic stroke. A histopathologic evaluation with embolectomy is important for diagnosing tumor emboli.

Background The development of new diagnostic technologies for cerebrovascular diseases requires an understanding of the mechanism behind the growth and rupture of cerebral aneurysms. To provide a comprehensive diagnosis and prognosis of this disease, it is desirable to evaluate wall shear stress, pressure, deformation and strain in the aneurysm region, based on information provided by medical imaging technologies. Methods In this research, we propose a new cyber-physical system composed of in vitro dynamic strain experimental measurements and computational fluid dynamics (CFD) simulation for the diagnosis of cerebral aneurysms. A CFD simulation and a scaled-up membranous silicone model of a cerebral aneurysm were completed, based on patient-specific data recorded in August 2008. In vitro blood flow simulation was realized with the use of a specialized pump. A vision system was also developed to measure the strain at different regions on the model by way of pulsating blood flow circulating inside the model. Results Experimental results show that distance and area strain maxima were larger near the aneurysm neck (0.042 and 0.052), followed by the aneurysm dome (0.023 and 0.04) and finally the main blood vessel section (0.01 and 0.014). These results were complemented by a CFD simulation for the addition of wall shear stress, oscillatory shear index and aneurysm formation index. Diagnosis results using imaging obtained in August 2008 are consistent with the monitored aneurysm growth in 2011. Conclusion The presented study demonstrates a new experimental platform for measuring dynamic strain within cerebral aneurysms. This platform is also complemented by a CFD simulation for advanced diagnosis and prediction of the growth tendency of an aneurysm in endovascular surgery. Copyright © 2013 John Wiley & Sons, Ltd.

Background: Computer-based simulation is necessary to clarify the hemodynamics in brain aneurysm. Specifically for endovascular treatments, the effects of indwelling intravascular devices on blood stream need to be considered. The most recent technology used for cerebral aneurysm treatment is related to the use of flow diverters to reduce the amount of flow entering the aneurysm. To verify the differences of flow reduction, we analyzed multiple Enterprise stents and two kinds of flow diverters. Materials and Methods: In this research, we virtually modeled three kinds of commercial intracranial stents (Enterprise, Silk, and Pipeline) and mounted to fit into the vessel wall, and deployed across the neck of an IC-ophthalmic artery aneurysm. Also, we compared the differences among multiple Enterprise stents and two flow diverters in a standalone mode. Results: From the numerical results, the values of wall shear stress and pressure are reduced in proportion to the size of mesh, especially in the inflow area. However, the reduced velocity within the aneurysm sac by the multiple stents is not as significant as the flow diverters. Conclusions: This is the first study analyzing the flow alterations among multiple Enterprise stents and flow diverters. The placement of small meshed stents dramatically reduced the aneurysmal fluid movement. However, compared to the flow diverters, we did not observe the reduction of flow velocity within the aneurysm by the multiple stents.

Computer-based simulations are essential for clarifying the hemodynamics of brain aneurysms. Since cerebrovascular disease is often fatal, it is strongly desirable to predict its progression. While previous studies have clarified the initiation mechanism of aneurysms, their growth mechanism remains unclear. Consequently, it is difficult to develop a diagnostic system for predicting aneurysm rupture. This study seeks to clarify the mechanism of aneurysm growth by identifying significant hydrodynamic factors. We focus on a single ruptured aneurysm that was followed up for five years. Computer simulations and fluid dynamic experiments with silicone vessel models were performed. To confirm the reliability of data in the computer simulations, we conducted particle image velocimetry measurements in steady flow. We then performed computer simulations for pulsatile conditions to determine an effective index for aneurysm growth. We obtained good agreement between the trends in the obtained computer simulation and experimental data. Numerical simulations for pulsatile flow in three models revealed that aneurysms grew in regions having a low wall shear stress, a low aneurysm formation indicator, and a high oscillatory shear index.

We describe a patient with subcutaneous hematoma associated with manual cervical massage during carotid artery stenting. A 73-year-old man with left cervical carotid artery stenosis presented with left amaurosis fugax. We performed carotid artery stenting using distal embolic protection with balloon occlusion. Dual antiplatelet therapy was maintained in the periprocedural period and an anticoagulant agent was administered during the procedure. Because the aspiration catheter became entrapped by the stent, it did not reach the distal side of the stenotic lesion, and manual compression of the cervical region was therefore performed. Immediately afterwards, a subcutaneous hemorrhage occurred in the cervical region. There was no postoperative dyspnea due to enlargement of the hematoma, which was absorbed spontaneously. Cervical subcutaneous hematoma can occur in the cervical region due to cervical massage in patients who are receiving adjuvant antiplatelet therapy and anticoagulation therapy.

Several advanced multiple catheter techniques have been invented for endovascular treatment. Stent-supported coil embolization is one of the most useful methods for wide neck aneurysms. We report 13 vertebral artery aneurysms treated with this method and discuss its efficacy. Between April 1999 and March 2006, we treated 13 patients with wide neck vertebral aneurysms, comprising 9 males and 4 females aged 38 to 79 (mean 60.0 years old) and treated with stent-supported coil embolization. Stent for coronary intervention was used in all cases. Using our original method, the microcatheter was inserted into the aneurysmal sac in advance, followed by deployment of the stent at the orifice. In this method, the microcatheter is placed out of the stent, which is useful to stabilize the microcatheter and to prevent the kick-back of microcatheter into the parent artery. Further, we repeated the inflation of balloon catheter at the orifice to prevent the coil herniation whenever placing coils. Complete obliteration of the aneurysm was achieved in 9 patients and subtotal occlusion in 4 patients. Two stents were needed in 1 patient because of stent migration into the aneurysm. A stent slipped down during withdrawal of the balloon catheter in 1 case without coil herniation or vessel injury. In follow-ups of 3 months to 7 years, there was no recurrence except for 1 case whose aneurysm regrew resulting in trapping of VA. The only procedure-related symptomatic complication was 1 case with transient abducens nerve palsy. Stent supported coil embolization for wide-based vertebral aneurysms is a very useful and valuable technique. It permanenty prevents coil herniation and the rectification of parent artery flow. Although sufficient results were initially obtained, long term follow-up should be carried out.

We reviewed 84 AVMs embolized over 7 years and studied the significance of the embolization for associated aneurysms. Out of 84 AVMs, 14 were preoperatively embolized and 66 were followed by radiosurgery. Ten intranidal aneurysms were found in 9 cases, all of which ruptured. Although 8 aneurysms were completely embolized, using glue, 2 incompletely treated aneurysms rebled. Out of 6 proximal feeder aneurysms, 3 ruptured ones were treated with detachable coils and have shown no rebleeding. The other 3 aneurysms that increased in size during the follow-up after the embolization of AVM were embolized without complications. Two flow-related aneurysms remained, and an AVM nidus was primarily treated. Both aneurysms disappeared after the embolization of AVM. The ruptured proximal feeder aneurysms located far from the nidus, which require another approach for the removal of AVM, should be embolized with coils to reduce surgical invasiveness. Embolization of intranidal aneurysms is very useful for the prevention of rebleeding, particularly in cases followed by radiosurgery. Among the flow-related aneurysm treatments, AVM may be the treatment of choice. As for the treatment strategy of AVM, it is important to detect and identify the associated aneurysms and treat them appropriately.

We investigated the indications for endovascular treatment of unruptured cerebral aneurysms based on the natural history reported in ISUIA and our treatment results. At Nagoya University hospital and affiliated hospitals over 7 years we treated or attempted embolization for 383 unruptured aneurysms, including 301 asymptomatic and 82 symptomatic ones. Among them, 326 were treated with embolization and 57 were left untreated due to the high risks involved. Ruptures during the follow-up occurred in 2 symptomatic cases without treatment. We experienced 28 technical complications including 9 hemorrhagic, 14 ischemic and 4 others at the intra- and perioperative stage, in addition to 14 recanalizations at the delayed stage. The rate of morbidity associated with procedure was 4.0%. There was a high risk of hemorrhagic complications from a tiny anterior communicating artery aneurysm and ischemic complications in the middle cerebral, basilar-tip, and vertebral dissecting aneurysms with a hypoplastic posterior inferior cerebellar artery. As for the symptomatic aneurysms, although 72 patients had a good outcome, symptoms due to mass effects did not improve in 19 cases and worsened in 7. Particularly large paraclinoid aneurysms with visual symptoms showed a reduced possibility of symptom improvement. Although embolization has proved highly effective for the treatment of unruptured aneurysms, the treatment decision should take into account the relevant guidelines, including those for surgical option and observation. Abbreviations: ISUIA: International Study of Unruptured Intracranial Aneurysms

Despite recent technical advances in embolization of cerebral aneurysms with platinum coils, some aneurysms eventually resulted in incomplete packing with remnant neck or dome filling. Such a situation with a remaining inflow zone may pose a risk of rupture and subsequent regrowth. Metals characteristically generate heat under high-frequency alternating magnetic fields (AMF). We used this property to induce local hyperthermia and promote thrombogenesis in incompletely packed aneurysms. Glass model aneurysms packed with coils were subjected to AMF to investigate the correlation between weight of platinum and temperature elevation and the correlation between flow rates of water through the model and temperature elevation. Next, activated coagulation time (ACT) of blood obtained from dogs was studied at various temperatures. Finally, side-wall aneurysms created in the canine carotid artery using a venous patch were packed with platinum coils. Change in temperature and angiographic changes were investigated after AMF application. In the glass model, the weight of platinum was correlated with elevation of temperature, and a negative logarithmic correlation was evident between flow rate and elevation of temperature. Elevation of blood sample temperature tended to shorten ACT. In canine carotid aneurysms, elevation of intra-aneurysmal temperature was confirmed and sufficient elevation of temperature was found to promote angiographically evident thrombogenesis of the remnant space after AMF application. Local hyperthermia may be useful in completing luminal obliteration of aneurysms after coil embolization. It may particularly useful for ruptured aneurysms to prevent the early rerupture.

The authors carried out a retrospective review of the records of 12 patients with aneurysms of the posterior cerebral artery (PCA). Four were asymptomatic, 1 presented with a mass effect, and 7 with a subarachnoid haemorrhage (SAH). Of the 7 ruptured aneurysms, 3 were embolized and 2 were clipped. However, 2 patients died from rebleeding before any treatment. Of the 5 unruptured aneurysms, 1 was embolized with coils but the remaining 4 have been conservatively observed. No aneurysms have ruptured during the follow-up period, and 3 have thrombosed spontaneously. According to our results, the PCA aneurysms should be treated aggressively in the early phase. Although the preservation of the anatomical integrity of the PCA should naturally be one of the prime objectives, PCA occlusion may sometimes be inevitable when treating large or fusiform aneurysms. On the other hand, conservative therapy is one of the options for the treatment of incidentally encountered unruptured ones, because these have the possibility of spontaneous thrombosis.

This paper presents a novel hybrid medical stent device. This hybrid stent device formed by fractal mesh structures provides a flow-diverting effect and stent-assisted coil embolization. Flow-diverter stents decrease blood flow into an aneurysm to prevent its rupture. In general, the mesh size of a flow-diverter stent needs to be small enough to prevent blood flow into the aneurysm. Conventional flow-diverter stents are not available for stent-assisted coil embolization, which is an effective method for aneurysm occlusion, because the mesh size is too small to insert a micro-catheter for coil embolization. The proposed hybrid stent device is capable of stent-assisted coil embolization while simultaneously providing a flow-diverting effect. The fractal stent device is composed of mesh structures with fine and rough mesh areas. The rough mesh area can be used to insert a micro-catheter for stent-assisted coil embolization. Flow-diverting effects of two fractal stent designs were composed to three commercially available stent designs. Flow-diverting effects were analyzed using computational fluid dynamics (CFD) analysis and particle image velocimetry (PIV) experiment. Based on the CFD and PIV results, the fractal stent devices reduce the flow velocity inside an aneurism just as much as the commercially available flow-diverting stents while allowing stent-assisted coil embolization.

We treated 13 experimental wide-necked aneurysms of lateral type produced in dog carotid arteries with a vein-loaded stent system consisting of an autologous vein graft, a vein-carrier stent, and two other self-expanding Z-shaped stents. The vein-loaded stent, made by connecting the autologous vein graft to the vein-carrier stent, was implanted in the common carotid artery to seal the aneurysm's orifice, after which two booster stents were deployed. The distal stent was placed to fix the distal end of the vein graft, and the proximal stent was placed at the proximal venous portion of the vein-loaded stent to reinforce its proximal end. In this manner an intra-arterial bypass was established across the aneurysm. Of 13 aneurysms seven were completely occluded, preserving the parent artery. The remaining six procedures resulted in parent artery occlusion because of failures in stent deployment. Angiograms performed in within 1 week six successfully treated dogs revealed the parent artery to be patent in four but thrombosed in two. Histological study of successful cases showed as smooth intima with slight endothelial hypertrophy and partially organised thrombus. The intraluminal features were also observed with a vascular endoscope at the time of treatment in four dogs and at the time of follow-up angiography in two. The appearances corresponded well to the macroscopic findings in the specimens. Our vein-loaded stent system offers complete closure of the orifice, which does not occur with conventional stent placement. The method is believed to show clinical promise for treating wide-necked aneurysms not curable by embolisation of the sac.

We devised a vein-loaded stent system to immediately close the aneurysmal orifice without interrupting the parent arterial flow. Ten experimental wide-necked aneurysms located on canine common carotid arteries were treated with the implantation of a newly modified vein-loaded stent system. After deploying the stent, half of them were managed under administration of 50 mg of ticlopidine hydrochloride per day and the other half followed up without any anticoagulation therapy. Immediately after the stent placement, all aneurysms were completely obliterated with patency of the parent artery in the successfully implanted vessels in both groups. Follow-up angiography one week later disclosed complete occlusion of the aneurysm with patency of the parent artery in 67% (2/3) of the group with ticlopidine, while none of the group without drugs showed patency of the parent artery. The rate of patency of the parent artery was found to be improved by administration of ticlopidine, but was still lower than that of a conventional stent. Further modifications will be needed before clinical use.

We have treated 142 aneurysms with intrasaccular or parent artery occlusions. Selective intrasaccular occlusions were attempted on 109 cases. Total or subtotal saccular occlusion was achieved in 93 of 96 cases. Intrasaccular occlusion could not be achieved in 13 cases because of various reasons such as wide neck, branching from aneurysmal dome, difficult to catheterize, and aneurysm too small. Parent artery occlusion was attempted on 33 cases. Twenty-five patients had giant aneurysms of the internal carotid artery (ICA) at the cavernous portion. The rest of this group had dissecting or fusiform aneurysms of the vertebral artery. Parent artery occlusion was achieved in 30 cases with six ischemic symptoms. High percentage of occlusion rate and low morbidity and mortality for metallic coil embolization prove the efficacy of this endovascular treatment.

An image guide for aneurysm embolization based on three dimensional CT angiography is reported. Multiplanner reformation (MPR) can measure the neck and dome of the aneurysm accurately enough to select the first coils for aneurysms. For neck evaluation, cut model and virtual endoscope are helpful because we can observe the neck from inside of dome or parent artery. Proximal arteries are visualized by 3D images and MPR if needed. Using laser lithography, we can get a real model of aneurysm and parent artery through which we can insert microcatheters and coils. 3D CTA is a dependable modality for embolization of cerebral aneurysms.

For the development of artificial intelligent diagnosis for cerebrovascular intervention, it is desirable to forecast the growth of cerebral aneurysms. In order to achieve such purpose, it is needed to evaluate wall shear stress, strain, pressure, deformation and flow velocity in the aneurysm region. In this research, we focus on in-vitro strain and deformation measurements of cerebral aneurysm models, and propose a cyber-physical system, in which a scaled-up membranous silicone model of cerebral aneurysm was built and integrated with a specialized pump for the pulsatile blood flow simulation, and a vision system was constructed to measure the strain on different regions on the model with pulsatile blood flow circulated inside. Experimental results show that both distance and area strain maxima were larger for the aneurysm neck (0.042 and 0.052), followed by the aneurysm dome (0.023 and 0.04) and then by the main blood vessel section (0.01 and 0.014), which were complemented with computer fluid dynamics simulation for the inclusion of wall shear stress, oscillatory shear index and aneurysm formation index. Medical imaging data of the cerebral aneurysm in 2008 and 2011 was obtained. Diagnosis results have concordance with the aneurysm growth in 2011. The presented measurement method offers an option for measuring strain and deformation to be complementary with computer fluid dynamics and photoelastic stress analysis for advanced diagnostic in the endovascular surgery.

Computer based simulation is important for clarifying the hemodynamics in brain aneurysm. Specifically, for endovascular treatments, the effect of indwelling intravascular devices on blood stream needs to be considered. Most recent technology for cerebral aneurysm treatment is related with the use of flow diverters to reduce the amount of flow entering to the aneurysms. In this research, we present a new method for design of flow diverters and fitting them to patient specific vasculature models. This methodology enables to change porosity of the flow diverters as well as their location in the blood vessel. One coiling assist stent and two flow diverters were compared to estimate the effect of flow alteration in aneurysm for treatment of a cerebral aneurysm. From the numerical result, we can conclude that pore density and size of mesh affect the hemodynamics in aneurysm and high density and small size of pore produce reduction effect of pressure and wall shear stress on an aneurysm.

Computer based simulation is important for clarifying the hemodynamics in brain aneurysm. Specifically, for endovascular treatments, the effect of indwelling intravascular devices on blood stream needs to be considered. Some medical studies have reported many kinds of stents configuration in artery aneurysm. However, it is still unclear which configuration of stents is optimal for surgery. To verify the efficiency of flow reduction effect between different pattern of stents configuration, we placed stents virtually in brain aneurysm and analyzed fluid dynamics. In this study, we present the process of constructing 3D flow diverter stent from helix curve and a method for fitting them to patient specific vasculature wall. Aneurysmal fluid dynamics for three different configurations (half-Y, Y and cross-bar) by computational fluid dynamics (CFD) are carried in two kinds of commercially available stents in patient specific vessel model.

Bilateral, symmetrical, experimental aneurysms were produced with anastomosed vein flap in the carotid arteries of 24 mongrel dogs. Aneurysms were occluded with latex or silicone balloons on each side and observed angiographically from 2 weeks to 2 months. A histopathological study was performed subsequently using light and scanning electron microscopy. Rupture after balloon embolization occurred in five aneurysms; all of which were incompletely occluded by a silicone balloon. On subsequent angiograms, four silicone balloons and one latex balloon were found to have migrated into the aneurysm, resulting in aneurysmal expansion. Parent artery occlusion was more common with latex balloons than silicone balloons. Histopathologically, residual fresh thrombi, decreased proliferation of fibroblasts within the aneurysmal cavity, and poor endothelialization were present around the silicone balloon. These results suggest that the intra-aneurysmal organization, as seen in the aneurysm occluded by the silicone balloon, will be delayed because the balloon is not fixed within the aneurysm, and that this free-floating and rotating balloon causes repeated trauma to the aneurysm wall, contributing to subsequent enlargement and rupture of the aneurysm. The superior antithrombogenic nature of silicone may be responsible for the bias of such phenomena toward the silicone balloon.

An extracranial vertebral artery aneurysm in a patient with neurofibromatosis is described. The aneurysm was treated by endovascular balloon occlusion of the proximal vertebral artery. The details of the therapeutic management are discussed, and the vascular manifestations of neurofibromatosis are reviewed.

We describe a case of a 32-year-old woman with bilateral hypoplastic internal carotid arteries who presented with subarachnoid haemorrhage and was found to have two basilar trunk aneurysms. Carotid angiography showed that both internal carotid arteries were narrowed at their origin and terminated at the cervical segment. Vertebral angiography demonstrated a dilated vertebrobasilar system which supplied sufficient blood flow for both cerebral hemispheres through the posterior communicating arteries. The patient was successfully treated by multiple operations.

Extracranial vertebral artery aneurysm associated with neurofibromatosis (NF1) is very rare. The aneurysm was successfully treated by endovascular trapping of the aneurysm and proximal vertebral artery with coils.

Background: A limited series of patients with aneurysm were reviewed retrospectively to analyze strategies for integrating microsurgical and endovascular techniques in the management of complex, surgically intractable aneurysms. Methods: Four patients were managed in Fujita Health University with a multimodality approach: intentional reconstruction of the aneurysm neck followed by endovascular coiling. Results: A total of 5 aneurysms were treated, of which 3 were large or giant in size, and 3 were fusiform or multilobulated. Complete angiographic obliteration was confirmed in 4 aneurysms (80%). All patients had a good outcome (Glasgow Outcome Scale score 5; mean follow-up, 64 months). Conclusion: As for complex, surgically intractable aneurysms, the intentional reconstruction of the aneurysm neck followed by endovascular coiling should be considered more often.

Summary: Electrocardiographically (ECG) gated multisection helical CT images were obtained in 23 patients with ruptured intracranial aneurysms. 4D-CTA (3D CT angiography plus phase data) images were generated by ECG-gated reconstruction. Four patients showed pulsation of an aneurysmal bleb. Clipping was performed in two of these patients, and the rupture site matched the pulsatile bleb seen in 4D-CTA.

The year 2004 in interventional neuroradiology has been distinguished by the steady accumulation of evidence to validate the efficacy of therapeutic procedures, such as carotid angioplasty and stenting (CAS) for cerebrovascular atherosclerosis. There is increasing momentum to design trials that will validate the role of endovascular therapy in the treatment of acute stroke and other cerebrovascular disorders. Practice patterns continue to evolve as evidence-based principles are applied to interventional therapy. In September 2004, the US Food and Drug Administration approved the use of stents for the treatment of atherosclerotic disease of the carotid bifurcation. This approval was based on data from the industry-supported Acculink for Revascularization of Carotids in High Risk patients (ARCHeR)1 registry and the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial.2 ARCHeR showed a 10% complication rate for CAS in 581 high-risk patients compared with a 15% complication rate derived from the carotid endarterectomy (CEA) literature. SAPPHIRE was a randomized control trial (RCT) comparing CAS to CEA in 334 high-risk patients. Primary end points were the cumulative incidence of death, stroke, or myocardial infarction within 30 days and death or ipsilateral stroke between 31 days and 1 year. The overall rate of primary end points was 39% lower in the CAS group, and CAS resulted in complication rates for all adverse events ≤CEA in both symptomatic and asymptomatic patients. The authors believe they have proven their hypothesis that CAS with distal protection is not inferior to CEA in high-risk patients. Criticisms of the study include the large proportion of asymptomatic patients, bias favoring CAS due to unequal randomization, the inclusion of many patients with recurrent stenoses after prior CEA, small sample size, and controversial end points, such as myocardial infarction and cranial nerve palsy.3 The evidence is also …

Stent assisted coil embolization is a useful therapeutic modality for wide-necked and geometrically difficult aneurysms, as the stent provide a buttress that allows for coil deposition while preventing coil haerniation into the parent vessel lumen, and placement of an endovascular stent within the parent artery across the aneurysm neck may divert the blood from the aneurysm inflow tract and promote intra-aneurysm stasis and thrombosis. We report herein a 3 patients treated with endovascular stent-assisted coil embolization for symptomatic or enlarging wide-necked, dissecting, and fusiform aneurysms of the carotid and vertebrobasilar arteries. One patient had intracranial mass effect, the second had subarachnoid haemorrhage, and the third had angiographic evidence of enlarging aneurysm. The aneurysm was located in the petrous segment of internal carotid artery in one patient and in the intracranial vertebral artery in the other two patients. For all patients, we used balloon expandable stent (such as GFX, S-670) in this technique. Complete obliteration of the aneurysms could be achieved in all cases, with preservation of distal circulation.

The authors reviewed 531 patients with cerebral aneurysms treated with Guglielmi detachable coils (GDCs) over 5 years to clarify both the advantages and disadvantages of embolization based on the evidence of complications by aneurysm profile. There were 52 technical complications, 25 of which resulted in unfavorable patient outcomes. Intraoperative rupture, the most serious complication exacerbating the patient's condition, occurred in 19 patients, 4 of whom expired. All of these aneurysms were very small and were mostly located in the AcomA and PICA portions. Thirteen patients encountered thromboembolic complications, 6 of whom were elderly with acute ruptured aneurysms at MCA and the tip of BA. For large or giant aneurysms manifesting the mass effect, particularly those in the ICA-C2 portion compressing the optic nerve, the saccular packing did little to ameliorate the symptoms, and subsequent surgical or endovascular trapping was needed. Therefore, saccular embolization of endovascularly difficult, very small AcomA aneurysms and large C2 aneurysm with visual symptoms should be used sparingly based on a risk-benefit assessment.

Arterial dissection is now recognized as an important cause of stroke. Most reported dissections involve the extracranial portion of the internal carotid artery (ICA) and vertebral arteries. Spontaneous dissecting aneurysms of the intracranial ICA are uncommon. Endovascular treatment for cerebral aneurysms has become widespread; however, the dissecting aneurysm is still difficult to treat if the parent artery has to be preserved. More recently, stenting has been advocated for use with endosaccular coiling, with the coils held in place by the stent. We herein report a spontaneous intracranial ICA dissecting aneurysm in a 51-year-old woman who was treated using a new technique of combined stent and coils.

BACKGROUND AND PURPOSE: The pathogenesis and optimal treatment for arterial dissection are still unclear. We devised an experimental model of arterial dissection and observed the morphologic changes with angiography. METHODS: Sixty-four experimental dissections were created in the common carotid arteries of 34 mongrel dogs. After a small incision was made in the arterial adventitia, it was dissected from the media. Elliptical defects (2, 4, 6, and 8 mm in groups I-A, I-B, I-C, and I-D, respectively; n = 47) or longitudinal incisions (4, 6, and 8 mm in groups II-A, II-B, and II-C, respectively; n = 17) were made in the intima distal to the adventitial incision to serve as an entry zone for dissection. RESULTS: Immediately after the lesions were created, the influx of blood into the dissected cavity produced massive subadventitial hematomas, resulting in stenotic changes in all of the arteries, including seven with occlusion. Follow-up (1-week) angiograms demonstrated complete healing, with normal arterial calibers in 11 (79%) of 14 I-A lesions and aneurysm formation in nine (69%) of 13 I-B lesions. All 10 I-D lesions had complete arterial occlusion. Persistent stenosis was observed in all 10 I-C lesions; six of these developed aneurysms. Pathologic examination of the freshly dissected cavities revealed a clot-filled cleft between the media and adventitia. Mature aneurysms, evaluated 3 mo later, had endothelialization within the aneurysmal dome. CONCLUSION: Morphologic changes after arterial dissection are closely related to the size of the intimal entry zone, which may determine whether a dissecting aneurysm forms.

Reinforcing an aneurysmal wall is one possible way to prevent from aneurysm rupture. We preliminarily tried focal gene transfer against the wall of experimental aneurysms to aim the transgene remodeling of aneurysmal wall. Two experimental saccular aneurysms were created on canine common carotid artery with an artificial dissecting method, which resemble clinical aneurysms. Adenovirus vector (AxCALacZ, 108 pfu) was slowly injected into the aneurysm cavity for over 30 minutes under the condition of in-traaneurysmal flow arrest using balloon-assisted neck-plasty technique. The arteries and aneurysms were evaluated 48 hours after the transduction with X-gal staining, and β-galac-tosidase expression was detected mainly in the intima in both cases. No adverse effects on the normal carotid wall and no systemic complications were observed after the procedure. This experimental study suggests the possibility of gene therapy for cerebral aneurysms.

We present a comparison of clinical results between GDC treatment and direct surgery for ruptured cerebral aneurysms. From May 97 to April 98, 32 aneurysms were treated by direct surgery (DS) or GDC treatment. Treatments were selected depending on the clinical grade, degree of hematoma and anatomical aspect of the aneurysms. There were 13 GDC treated cases and 19 direct surgery cases. In GDC cases, there were acute stage embolization for ruptured basilar aneurysm, recurrence of case after clipping for BA-SCA aneurysm, advanced age cases, and systemic complication cases. Glasgow outcome scale (GOS) in GDC cases were 8 GR, 2 MD and 3 SD. GOS in direct surgery cases were 7 GR, 4 MD, 4 SD and 4 deaths. Cases of severe subarachnoid hemorrhage with hematoma influenced the high death rate in direct surgery group. There were three complications associated with the procedure in the GDC group, however, the rate improved after advancement of the procedure. In conclusion, GDC treatment for ruptured cerebral aneurysm was satisfactorily acceptable compared to the results of direct surgery, however, more cases will be needed for precise comparison.

OBJECTIVE: We developed an in vivo model of growing fusiform aneurysms, using vein grafts to the rat carotid artery. This aneurysm model might demonstrate the pathological features of the development and growth of aneurysms to become giant aneurysms. METHODS: Placement of an interposed femoral vein graft to restore carotid artery flow was performed in Wistar rats. On Day 21, 75% of the grafts (mean diameter, 1.6 mm) were found to be dilated to resemble fusiform aneurysms (mean diameter, 5.82 mm), and 53% of these were giant. Quantitative analysis of the histological findings was performed using image-analyzing software. RESULTS: Histological findings were similar to those for human intracranial giant aneurysms. The average length of the initial grafts in the aneurysm group was 9.1 ± 1.9 mm, and grafts were significantly longer and more tortuous than in the normal graft group (6.4 ± 0.8 mm) (P = 0.01). Cross-sectional areas of the aneurysms (mean, 18.9 mm 2 ) were significantly correlated with the following: 1) the area of intra-aneurysmal thrombosis (mean, 11.1 mm 2 ) (P < 0.0001); 2) the number of intrathrombotic vascular channels (P = 0.005); and 3) the area of dissection, with hemorrhage, between the thrombus and the wall of the aneurysm (mean, 0.72 mm 2 ) (P = 0.0013). Scanning electron microscopic examination showed evidence of endothelial damage associated with growth of the aneurysms. CONCLUSION: Recurrent hemorrhaging from intrathrombotic vascular channels caused dissection between the thrombus and the aneurysm wall, which led to growth of the experimental aneurysms to giant aneurysms. With this model, we demonstrated the growth mechanism of giant fusiform aneurysms.

Surgery for partially thrombosed giant and large aneurysms is technically more difficult than for nonthrombosed aneurysms. Treatment strategies consisting of intravascular embolization, direct clipping and bypass surgery must be made according to the location, size and degree of thrombosis of the aneurysms and collateral flow. Among 64 giant and large aneurysms 27 were partially thrombosed. Direct clipping was performed in 18, combined interventional and direct surgery in 3 and interventional surgery alone in 6 patients. Surgical results were good in 24, poor in two with death in one patients. Good indications for intravascular surgery are aneurysms in the intracavernous carotid artery, vertebral artery, basilar tip and those unruptured aneurysms with less mass effect in elderly patients. For direct clipping, parent artery is trapped after heparinization and aneurysm is opened at a place more than 5 mm away from the parent artery in order to obtain enough space for multiple clips. After thrombectomy best fitting clips were selected from over 80 different shapes of Sugita clips. Large clips of over 21 mm, fenestrated clips and booster clips were most frequently used. Three to six clips were needed to occlude the wide and thick neck of each aneurysm. Direct clipping with aneurysmectomy was the most preferable procedure from the point of decompression and complete cure for the ruptured, partially thrombosed giant and large aneurysms with mass effects.

Improvements in blood elimination and the development of an ultrathin, flexible fibrescope have made it possible to perform intravascular endoscopy safely and effectively. A new endoscopic system was used to occlude experimental aneurysms created in canine carotid arteries. Endoscopy provides valuable information about the aneurysmal orifice and lumen and is helpful in balloon placement and detachment.

Recent advance of endovascular treatment has brought a significant change in the treatment of cerebral aneurysms. However, there are still unsolved problems in such treatment. In this study we are seeking the definitive method of endovascular therapy. An experimental aneurysm was first produced in the carotid artery of a dog by the venous patch method. Follow-up study of these aneurysms revealed 80% patency rate during a 3-month period. The aneurysm was then treated by detachable latex balloon. Treated aneurysms were studied angiographically and histologically. After 4 weeks the aneurysm lumen was completely covered by epithelial cells. Latex balloon has a satisfactory ability to occlude a large aneurysmal cavity.