Flow changes caused by the sequential placement of stents across the neck of sidewall cerebral aneurysms

2005 ◽  
Vol 103 (5) ◽  
pp. 891-902 ◽  
Author(s):  
Gádor Cantón ◽  
David I. Levy ◽  
Juan C. Lasheras ◽  
Peter K. Nelson
Keyword(s):  
Shear Stress ◽  
Velocity Field ◽  
Cerebral Aneurysms ◽  
Parent Artery ◽  
Shear Stresses ◽  
Content Type ◽  
Aneurysm Neck ◽  
Aneurysm Wall ◽  
Aneurysm Model ◽  
Fine Print

Object. The goal of this study was to quantify the reduction in velocity, vorticity, and shear stresses resulting from the sequential placement of stents across the neck of sidewall cerebral aneurysms. Methods. A digital particle image velocimetry (DPIV) system was used to measure the pulsatile velocity field within a flexible silicone sidewall intracranial aneurysm model and at the aneurysm neck–parent artery interface in this model. The DPIV system is capable of providing an instantaneous, quantitative two-dimensional measurement of the velocity vector field of “blood” flow inside the aneurysm pouch and the parent vessel, and its changes at varying stages of the cardiac cycle. The corresponding vorticity and shear stress fields are then computed from the velocity field data. Three Neuroform stents (Boston Scientific/Target), each with a strut thickness between 60 and 65 µm, were subsequently placed across the neck of the aneurysm model and measurements were obtained after each stent had been placed. The authors measured a consistent decrease in the values of the maximal averaged velocity, vorticity, and shear stress after placing one, two, and three stents. Measurements of the circulation inside the sac demonstrated a systematic reduction in the strength of the vortex due to the stent placement. The decrease in the magnitude of the aforementioned quantities after the first stent was placed was remarkable. Placement of two or three stents led to a less significant reduction than placement of the first stent. Conclusions. The use of multiple flexible intravascular stents effectively reduces the strength of the vortex forming in an aneurysm sac and results in a decrease in the magnitude of stresses acting on the aneurysm wall.

Endovascular treatment of intracranial aneurysms: comparative evaluation in a terminal bifurcation aneurysm model in dogs

2004 ◽  
Vol 101 (6) ◽  
pp. 996-1003 ◽  
Author(s):  
Yoshikazu Yoshino ◽  
Yasunari Niimi ◽  
Joon K. Song ◽  
Michael Silane ◽  
Alejandro Berenstein
Keyword(s):  
Side Wall ◽  
Parent Artery ◽  
Content Type ◽  
Aneurysm Neck ◽  
Bifurcation Aneurysm ◽  
Group 3 ◽  
Group 2 ◽  
Aneurysm Model ◽  
Fine Print ◽  
Group 1

Object. The authors investigated whether HydroCoils decreased coil compaction and aneurysm recanalization in a canine model of a large, wide-necked, high-flow bifurcation aneurysm. Methods. Eleven experimental aneurysms were created. Two aneurysms were untreated (Group 1); three were treated with standard platinum coils (Guglielmi Detachable Coils; Group 2); and six were treated with platinum framing coils and filling HydroCoils (Group 3). Comparative angiographic and histopathological data were analyzed at 2 weeks and again at 3 months. At 3 months, the Group 1 aneurysms remained patent without spontaneous thrombosis. After coil placement the percentage of aneurysm filling by volume ranged from 59 to 90% (mean 75.4%) for Group 3 (HydroCoil-treated) and 34.3 to 48.9% (mean 39.6%) for Group 2 (GDC-treated) (p < 0.05). At 14 days, two of the three Group 2 aneurysms exhibited coil compaction and aneurysm recanalization at the neck; in both cases the condition worsened at 3 months. At 14 days and 3 months, five of the six Group 3 aneurysms were 100%, and one of six was 90% occluded and remained stable. At 3 months, the neointima of the aneurysm neck was significantly thicker in the Group 3 lesions, which had been treated by HydroCoils (0.329 ± 0.191 mm), than in Group 2 lesions, which had been treated with GDCs (0.026 ± 0.018 mm) (p , 0.001). No thrombus formation occurred in Group 2; however, in two of the six aneurysms in Group 3, thrombus formed at the coil—neck interface. Conclusions. The experimental canine bifurcation aneurysm model overcomes the limitations of side-wall aneurysm models. In this model, HydroCoils resulted in significantly denser coil packing, less follow-up coil compaction, and thicker neointimal tissue at the neck of the lesion. HydroCoils also appeared more thrombogenic at the aneurysm neck—parent artery interface.

Detachable balloon embolization therapy of posterior circulation intracranial aneurysms

1989 ◽  
Vol 71 (4) ◽  
pp. 512-519 ◽  
Author(s):  
Randall T. Higashida ◽  
Van V. Halbach ◽  
Leslie D. Cahan ◽  
Grant B. Hieshima ◽  
Yoshifumi Konishi
Keyword(s):  
Basilar Artery ◽  
Intracranial Aneurysms ◽  
Posterior Circulation ◽  
Parent Artery ◽  
Parent Vessel ◽  
Detachable Balloon ◽  
Content Type ◽  
Aneurysm Neck ◽  
Balloon Embolization ◽  
Fine Print

✓ Treatment of complex and surgically difficult intracranial aneurysms of the posterior circulation is now being performed with intravascular detachable balloon embolization techniques. The procedure is carried out under local anesthesia from a transfemoral arterial approach, which allows continuous neurological monitoring. Under fluoroscopic guidance, the balloon is propelled by blood flow through the intracranial circulation and, in most cases, can be guided directly into the aneurysm, thus preserving the parent vessel. If an aneurysm neck is not present, test occlusion of the parent vessel is performed and, if tolerated, the balloon is detached. Twenty-six aneurysms in 25 patients have been treated by this technique. The aneurysms have involved the distal vertebral artery (five cases), the mid-basilar artery (six cases), the distal basilar artery (11 cases), and the posterior cerebral artery (four cases). The aneurysms varied in size and included three small (< 12 mm), 15 large (12 to 25 mm), and eight giant (> 25 mm). Fifteen patients (60%) presented with hemorrhage and 10 patients (40%) with mass effect. In 17 cases (65%) direct balloon embolization of the aneurysm was achieved with preservation of the parent artery. In nine cases (35%), because of aneurysm location and size, occlusion of the parent vessel was performed. Complications from therapy included three cases of transient cerebral ischemia which resolved, three cases of stroke, and five deaths due to immediate or delayed aneurysm rupture. The follow-up period has ranged from 2 months to 43 months (mean 22.5 months). In cases where posterior circulation aneurysms have been difficult to treat by conventional neurosurgical techniques, intravascular detachable balloon embolization may offer an alternative therapeutic option.

Antegrade recanalization of a completely embolized vertebral artery after endovascular treatment of a ruptured intracranial dissecting aneurysm

2005 ◽  
Vol 102 (1) ◽  
pp. 161-166 ◽  
Author(s):  
Motoshi Sawada ◽  
Yasuhiko Kaku ◽  
Shinichi Yoshimura ◽  
Masahiro Kawaguchi ◽  
Takashi Matsuhisa ◽  
...  
Keyword(s):  
Vertebral Artery ◽  
Cerebral Aneurysms ◽  
Systemic Circulation ◽  
Parent Artery ◽  
Content Type ◽  
Endovascular Occlusion ◽  
Aneurysmal Dilation ◽  
Dissecting Aneurysms ◽  
Fine Print

✓ Occlusion of the parent artery is a traditional method of treatment of unclippable cerebral aneurysms. Surgical or endovascular occlusion of the parent artery proximal to the aneurysm has been recommended for the treatment of dissecting aneurysms located in the vertebrobasilar circulation. Nevertheless, occlusion of the parent artery may not result in permanent exclusion of the aneurysm from the systemic circulation because, occasionally, postoperative rebleeding occurs after proximal occlusion. Alternatively, endovascular occlusion of the affected site, including the aneurysmal dilation, and parent artery, is a safe and reliable treatment for dissecting aneurysms. The authors present two rare cases of ruptured vertebral artery (VA) dissecting aneurysms that were treated by endovascular occlusion of the affected site including the aneurysm and parent artery by using Guglielmi detachable coils. In both cases the VA recanalized in an antegrade fashion during the follow-up period. Based on these unique cases, the authors suggest that a careful angiographic follow up of dissecting aneurysms is required, even in patients successfully treated with endovascular occlusion of the affected artery and aneurysm.

Wrap-clipping with a Dacron mesh Silastic sheet

1994 ◽  
Vol 80 (2) ◽  
pp. 336-337 ◽  
Author(s):  
Kazuhiko Fujitsu ◽  
Yuusuke Ishiwata ◽  
Gakuji Gondo ◽  
Satoshi Fujii ◽  
Deng Dong Feng
Keyword(s):  
Outer Surface ◽  
Cranial Nerves ◽  
Cerebral Aneurysms ◽  
Parent Artery ◽  
Content Type ◽  
Clipping Technique ◽  
Mesh Coating ◽  
Closing Pressure ◽  
Fine Print ◽  
Dacron Mesh

✓ A technique combining wrapping and clipping using a Silastic sheet coated with Dacron mesh is described for treatment of fusiform or broad-based cerebral aneurysms. This sheet is easily tailored to wrapping the aneurysm base while avoiding involvement of the cranial nerves or branching vessels. The sheet is semitransparent so that the caliber of the newly constructed parent artery is easily adjusted during wrap-clipping. After the aneurysm and the parent artery have been circumferentially wrapped with the sheet, aneurysm clips are applied on the sheet so that the base of the aneurysm is clipped between the two leaves of the sheet. This wrap-clipping technique avoids the risks involved in extracting the aneurysm from the parent artery. The Dacron mesh coating the outer surface and sufficient clip closing pressure are both helpful in preventing the clip blades from sliding. Similar previously reported techniques are reviewed and discussed in detail.

scholarly journals Optical coherence tomography: a new method to assess aneurysm healing

2005 ◽  
Vol 102 (2) ◽  
pp. 348-354 ◽  
Author(s):  
William E. Thorell ◽  
Michael M. Chow ◽  
Richard A. Prayson ◽  
Mark A. Shure ◽  
Sung W. Jeon ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Coil Embolization ◽  
Imaging Modality ◽  
Cerebral Aneurysms ◽  
Biological Tissues ◽  
Optical Coherence ◽  
Content Type ◽  
Aneurysm Neck ◽  
Fine Print

Object. Aneurysmal subarachnoid hemorrhage affects approximately 10/100,000 people per year. Endovascular coil embolization is used increasingly to treat cerebral aneurysms and its safety and durability is rapidly developing. The long-term durability of coil embolization of cerebral aneurysms remains in question; patients treated using this modality require multiple follow-up angiography studies and occasional repeated treatments. Methods. Optical coherence tomography (OCT) is an emerging imaging modality that uses backscattered light to produce high-resolution tomography of optically accessible biological tissues such as the eye, luminal surface of blood vessels, and gastrointestinal tract. Vascular OCT probes in the form of imaging microwires are presently available—although not Food and Drug Administration—approved—and may be adapted for use in the cerebral circulation. In this study the authors describe the initial use of OCT to make visible the neck of aneurysms created in a canine model and treated with coil embolization. Optical coherence tomography images demonstrate changes that correlate with the histological findings of healing at the aneurysm neck and thus may be capable of demonstrating human cerebral aneurysm healing. Conclusions. Optical coherence tomography may obviate the need for subsequent follow-up angiography studies as well as aid in the understanding of endovascular tissue healing. Data in this study demonstrate that further investigation of in vivo imaging with such probes is warranted.

Intraoperative factors associated with surgical outcome in patients with unruptured cerebral aneurysms: the experience of a single surgeon

2003 ◽  
Vol 99 (3) ◽  
pp. 452-457 ◽  
Author(s):  
Arthur A. Grigorian ◽  
Alvin Marcovici ◽  
Eugene S. Flamm
Keyword(s):  
Cerebral Artery ◽  
Cerebral Aneurysms ◽  
Predictive Tool ◽  
Content Type ◽  
Unruptured Aneurysms ◽  
Aneurysm Neck ◽  
Unruptured Cerebral Aneurysms ◽  
Unexpected Outcomes ◽  
Expected Outcomes ◽  
Fine Print

Object. Some well-known predictors of clinical outcomes in patients with ruptured aneurysms are not useful for forecasting outcome in patients with unruptured aneurysms. The goal of this study was to analyze outcomes in patients harboring unruptured cerebral aneurysms in different locations and to create a predictive tool for assessing both favorable outcome and morbidity in a large series of unruptured aneurysms. Methods. The authors analyzed data from 387 patients with nonruptured intracranial cerebral aneurysms who underwent surgery for clip placement. Intraoperative data were reviewed and seven factors that might influence outcomes were identified. These included the following: 1) aneurysm size larger than 10 mm; 2) presence of a broad aneurysm neck; 3) presence of plaque calcification near the aneurysm neck; 4) application of clips to more than one aneurysm during the same surgery; 5) temporary occlusion; 6) multiple clip applications and repositioning; and 7) use of multiple clips. The entire group of patients with unruptured aneurysms was divided into two subgroups on the basis of outcome. Each patient was subsequently assessed to formulate the factor accumulation index (FAI), the sum of different factors observed in a given patient. The subgroup of patients with expected outcomes was composed of 312 patients, whereas the subgroup of unexpected outcomes consisted of 31 patients. Depending on the anatomical locations of the aneurysms, the combined mortality—morbidity rate ranged from 5.7 to 25%, with the best results for patients harboring ophthalmic artery aneurysms and the worst results for those with vertebrobasilar system (VBS) aneurysms. The majority of patients with expected outcomes who harbored aneurysms of the middle cerebral artery, the internal carotid artery, and the VBS had a lower FAI, whereas the majority of patients with unexpected outcomes had a higher FAI. Conclusions. It is possible to predict outcomes in patients with unruptured cerebral artery aneurysms by calculating the FAI. The rate of postoperative morbidity increases with the FAI within the range of three to four factors.

Intraaneurysmal flow dynamics study featuring an acrylic aneurysm model manufactured using a computerized tomography angiogram as a mold

2001 ◽  
Vol 95 (6) ◽  
pp. 1020-1027 ◽  
Author(s):  
Satoshi Tateshima ◽  
Yuichi Murayama ◽  
J. Pablo Villablanca ◽  
Taku Morino ◽  
Hikoichiro Takahashi ◽  
...  
Keyword(s):  
Shear Stress ◽  
Cardiac Cycle ◽  
Three Dimensional ◽  
Flow Dynamics ◽  
3D Ct ◽  
Content Type ◽  
Flow Profiles ◽  
Ct Angiogram ◽  
Aneurysm Model ◽  
Fine Print

Object. To obtain precise flow profiles in patients' aneurysms, the authors developed a new in vitro study method featuring an aneurysm model manufactured using three-dimensional computerized tomography (3D CT) angiography. Methods. A clear acrylic basilar artery (BA) tip aneurysm model manufactured from a patient's 3D CT angiogram was used to analyze flow modifications during one cardiac cycle. Stereolithography was utilized to create the aneurysm model. Three-dimensional flow profiles within the aneurysm model were obtained from velocity measurements by using laser Doppler velocimetry. The aneurysm inflow/outflow zones changed dynamically in their location, size of their cross-sectional area, and also in their shapes over one cardiac cycle. The flow velocity at the inflow zone was 16.8 to 81.9% of the highest axial velocity in the BA with a pulsatility index (PI) of 1.1. The flow velocity at the outflow zone was 16.8 to 34.3% of the highest axial velocity of the BA, with a PI of 0.68. The shear stress along the walls of the aneurysm was calculated from the fluid velocity measured at a distance of 0.5 mm from the wall. The highest value of shear stress was observed at the bleb of the aneurysm. Conclusions. This clear acrylic model of a BA tip aneurysm manufactured using a CT angiogram allowed qualitative and quantitative analysis of its flow during a cardiac cycle. Accumulated knowledge from this type of study may reveal pertinent information about aneurysmal flow dynamics that will help practitioners understand the relationship among anatomy, flow dynamics, and the natural history of aneurysms.

Surgical treatment of distal anterior cerebral artery aneurysms

1979 ◽  
Vol 50 (1) ◽  
pp. 40-44 ◽  
Author(s):  
Takashi Yoshimoto ◽  
Keita Uchida ◽  
Jiro Suzuki
Keyword(s):  
Cerebral Artery ◽  
Anterior Cerebral Artery ◽  
Aneurysm Rupture ◽  
Anterior Communicating Artery ◽  
Parent Artery ◽  
Content Type ◽  
Aneurysm Neck ◽  
Horizontal Portion ◽  
Distal Anterior Cerebral Artery ◽  
Fine Print

✓ Between June, 1961, and September, 1975, the authors operated on 60 patients with aneurysms of the anterior cerebral artery distal to the anterior communicating artery (ACoA) by a direct intracranial approach. It is of utmost importance in the treatment of aneurysms to have control of the parent artery of the aneurysm. This makes it easier and safer to approach the aneurysm neck and to handle possible premature aneurysm rupture. The aneurysms were classified into two types, ascending and horizontal. Aneurysms arising from the origin of the ACoA and including the entire portion of the knee of the corpus callosum were designated as aneurysms of the ascending portion, whereas aneurysms beyond the genu were designated as aneurysms of the horizontal portion. For aneurysms of the ascending portion, bifrontal craniotomy was considered the safest approach. For aneurysms of the horizontal portion, a small parasagittal craniotomy was determined to be sufficient.

Vertebrobasilar occlusion therapy of giant aneurysms

1984 ◽  
Vol 60 (3) ◽  
pp. 560-565 ◽  
Author(s):  
David M. Pelz ◽  
Fernando Viñuela ◽  
Allan J. Fox ◽  
Charles G. Drake
Keyword(s):  
Carotid Artery ◽  
Posterior Circulation ◽  
Parent Artery ◽  
Content Type ◽  
Aneurysm Neck ◽  
Giant Aneurysms ◽  
Patient Will ◽  
Therapeutic Occlusion ◽  
Carotid Artery Compression ◽  
Fine Print

✓ The clinical and angiographic records were reviewed for 71 patients with giant aneurysms of the posterior circulation, who underwent therapeutic occlusion of the basilar artery or both vertebral arteries. This treatment is used when the aneurysm neck cannot be surgically clipped, and occlusion of the parent artery is performed to initiate thrombosis within the lumen. In these cases, collateral blood flow to the brain stem is supplied mainly by the posterior communicating arteries. Consequently, their angiographic morphology (patency, size, and number) is demonstrated as a preoperative indicator of whether the patient will be able to tolerate vertebrobasilar occlusion. Vertebral angiograms with carotid artery compression (the Allcock test) will often be needed to provide this information. The data relating posterior communicating artery morphology to clinical outcome in 71 cases of attempted vertebrobasilar occlusion are presented. The use and accuracy of carotid artery compression studies are also discussed. It is essential for the radiologist to supply the neurosurgeon with this valuable information in every case of giant posterior circulation aneurysm.

Limitations of three-dimensional reconstructed computerized tomography angiography after clip placement for intracranial aneurysms

2005 ◽  
Vol 103 (4) ◽  
pp. 656-661 ◽  
Author(s):  
Yoshiko Sagara ◽  
Hiro Kiyosue ◽  
Yuzo Hori ◽  
Michifumi Sainoo ◽  
Hirofumi Nagatomi ◽  
...  
Keyword(s):  
Ct Angiography ◽  
Computerized Tomography ◽  
Intracranial Aneurysms ◽  
Three Dimensional ◽  
Parent Artery ◽  
3D Ct ◽  
Metal Artifacts ◽  
Content Type ◽  
Aneurysm Neck ◽  
Fine Print

Object. The authors compared the usefulness of three-dimensional (3D) reconstructed computerized tomography (CT) angiography with 3D digital subtraction (DS) angiography in assessing intracranial aneurysms after clip placement. A retrospective review of clinical cases was performed. Methods. Between May 2001 and May 2003, 17 patients with a total of 20 intracranial aneurysms underwent 3D CT and 3D DS angiography following clip placement. The authors assessed the presence or absence of residual aneurysm necks and stenoocclusive changes in the parent artery and the neighboring artery. The efficacy of CT angiographic visualization was also evaluated. In 12 of the 20 aneurysms, both 3D modalities similarly demonstrated the residual aneurysm neck and stenoocclusive changes in the parent artery and neighboring artery. Three-dimensional CT angiography failed to demonstrate three of the aneurysms, and the studies were not considered suitable for evaluation because of the presence of metallic artifacts. In the remaining five studies, the 3D CT angiograms did not effectively demonstrate the neighboring and parent arteries. The detectability of residual aneurysm necks was correlated with the clip material and with the number of clips applied. Conclusions. Three-dimensional DS angiography is still necessary in cases involving multiple clips or with cobalt alloy clips because the clips appear as metal artifacts on 3D CT angiography.

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