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Sample records for arch aneurysm model

  1. Giant aortic arch aneurysm complicating Kawasaki′s disease

    OpenAIRE

    Kaouthar Hakim; Rafik Boussada; Lilia Chaker; Fatma Ouarda

    2014-01-01

    Kawasaki disease (KD) is a common acute vasculitis in pediatric population that usually involves small- and middle-sized arteries, commonly coronary arteries. Although the incidence and natural course of coronary aneurysms after KD are well documented in studies, related reports on peripheral arterial and aortic aneurysms are scarce. We report the occurrence of a giant aortic aneurysm involving the horizontal part of aortic arch in a 28-month-old boy diagnosed with KD. This complication was m...

  2. Branched and fenestrated options to treat aortic arch aneurysms.

    Science.gov (United States)

    Maurel, Blandine; Mastracci, Tara M; Spear, Rafaelle; Hertault, Adrien; Azzaoui, Richard; Sobocinski, Jonathan; Haulon, Stephan

    2016-10-01

    Conventional surgical repair of aortic arch aneurysms using cardiopulmonary bypass and hypothermic circulatory arrest remains the gold standard, however it is associated with a substantial mortality and morbidity rate, especially in the elderly. Hybrid techniques avoid aortic cross-clamping and circulatory arrest, but are of limited use and are only applicable to selected patients. The development of new devices to treat aortic arch aneurysms endovascularly has the potential to offer a treatment modality to patients unfit for an open repair. We present the challenges specific to endovascular arch repair based on our experience and the literature available from the first experience in 1999 to the third generation graft currently commonly used. Following an initial learning curve associated with the use of the third generation arch branch device, along with careful patient selection and operator experience, early results are promising. Technical success was achieved in all cases, there was no early mortality and strokes were noted in 11%. As with branched and fenestrated technology for thoracoabdominal aneurysm repair, the use of total endovascular repair for arch pathology will require an evolution in endovascular practice and device design. However, at present, the early use of the latest generation device offers a novel approach to patients who previously had no surgical options. PMID:27332680

  3. Mycotic aneurysm of the aortic arch presenting with left vocal cord palsy.

    Science.gov (United States)

    Tokmaji, George; Gosev, Igor; Kumamaru, Kanako Kunishima; Bolman, Ralph Morton

    2013-07-01

    We report a case of a 71-year-old man with a mycotic aneurysm of the aortic arch who presented with progressive hoarseness. Three weeks prior to this event the patient was admitted to an outside hospital in septic condition and was diagnosed with a mycotic abdominal aortic aneurysm. Resection of the infected abdominal aortic aneurysm with right axillofemoral and femoral-femoral bypass grafts was performed and the patient was discharged home on intravenous antibiotics. At our institution, the aortic arch aneurysm was treated with extensive debridement and replaced with a Dacron prosthesis under circulatory arrest with antegrade cerebral perfusion through the axillofemoral bypass. PMID:23816081

  4. Superficial Palmar Arch Aneurysm after Carpal Tunnel Decompression, a Rare Complication: A Case Report

    Directory of Open Access Journals (Sweden)

    S. Gull

    2011-01-01

    Full Text Available False aneurysms of the palmar arteries are rare. They are usually associated with traumatic injuries to the hand vasculature. We present a case of superficial palmar arch aneurysm (SPAA, complicating carpal tunnel decompression which presented as a pulsatile mass at the site of previous surgery. Initial diagnosis was made on clinical examination and confirmed on doppler ultrasound (US and computed tomographic angiography (CTA. The feeding vessel of the aneurysm was subsequently occluded using coil embolization.

  5. Medical image of the week: atherosclerotic aneurysm of aortic arch and decsecnding thoracic aorta

    Directory of Open Access Journals (Sweden)

    Parasram M

    2016-02-01

    Full Text Available No abstract available. Article truncated after 150 words. A 94-year-old Spanish-speaking woman presented to the hospital with intermittent episodes of dyspnea and abdominal pain for one week. Her past medical history was notable for 30 pack-year smoking history and hypertension, which was reportedly controlled with medical therapy. Physical exam showed trace peripheral edema bilaterally, intact peripheral pulses, and a mild abdominal bruit. Work up at the emergency department revealed a non-ST elevation myocardial infarction with troponin T of 0.34 ng/mL but no ST-wave abnormality on electrocardiography. Chest x-ray displayed an incidental thoracic aneurysm (Figure 1. Chest computed tomography with contrast demonstrated a continuous aneurysm of the aortic arch and descending thoracic aorta with diameters measuring 6.8 cm and 6 cm, respectively (Figure 2A and 2B. Eccentric thrombi are noted in the aortic arch and the descending aorta. Interestingly, the distal descending thoracic aorta curves as it transitions to the abdominal aorta, which is evidence of a tortuous descending ...

  6. [Hybrid surgical intervention in a patient with an aortic arch aneurysm and coronary artery disease].

    Science.gov (United States)

    Charchan, E R; Abugov, S A; Puretsky, M V; Kim, S Yu; Skvortsov, A A; Khachatryan, Z R

    2015-01-01

    Presented herein is a clinical case report regarding the use of hybrid technology in surgical treatment of a patient with an aneurysm of the distal portion of the aortic arch and coronary artery disease. The patient underwent a hybrid operation, i.e. debranching of the aortic arch branches, exoprosthetic repair of the ascending aorta, autovenous prosthetic coronary bypass grafting of the branch of the blunt edge of the anterior interventricular artery, stenting of the ascending portion, arch and descending portion of the aorta (stent graft "Medtronic Valiant"). In doing so, we used a non-standard approach to connecting the artificial circulation unit and to choosing the place for establishing proximal anastomoses of autovenous coronary bypass grafts. The early postoperative period was complicated by the development of respiratory insufficiency requiring continuation artificial pulmonary ventilation. The duration of the hospital stay of the patient amounted to 15 days. The check-up multispiral computed tomography showed normal functioning of the reconstruction zones, the stent graft is expanded, with no leak observed. The conclusion was made that hybrid interventions may be considered as an alternative to the classical surgical treatment associated in patients of older age group with a severe course of the postoperative period and high lethality. PMID:26035581

  7. Aneurysms of the ascending aorta and arch: the role of imaging in diagnosis and surgical management.

    Science.gov (United States)

    Bonnichsen, Crystal R; Sundt, Thoralf M; Anavekar, Nandan S; Foley, Thomas A; Morris, Michael F; Martinez, Matthew W; Williamson, Eric E; Glockner, James F; Araoz, Philip A

    2011-01-01

    Thoracic aortic aneurysms tend to be asymptomatic and were previously often diagnosed only after a complication such as dissection or rupture occurred. Better imaging techniques and an increase in the use of cross-sectional imaging has led to an increase in the diagnosis of aortic aneurysms, which has allowed for elective treatment prior to the development of a complication. The location, size and etiology of an aneurysm all impact the clinical outcomes and these factors are used to determine the appropriate timing of surgical replacement. Surgeons often rely on the information obtained from preoperative imaging to determine when to intervene and what type of procedure will be necessary, making it important for the radiologist to understand these issues in order to provide the necessary information. Postoperative imaging after surgical replacement of the aorta is also important, as there are some common findings that occur in this patient population that can impact how they are treated. The purpose of this article is to review the etiology and associated findings of aneurysms of the ascending aorta and arch, with a focus on how computed tomography angiography and magnetic resonance angiography findings are used to determine the appropriate timing for elective replacement and the type of surgical procedure, as well as the role of follow-up imaging. This will include a review of the most commonly performed types of surgical procedures, to provide an understanding of how the findings of preoperative imaging studies impact what the surgeon does in the operating room, as well as the expected findings of postoperative imaging studies. PMID:21166528

  8. [Hybrid operation for a posttraumatic saccular aneurysm of the aortic arch].

    Science.gov (United States)

    Ignat'ev, I M; Volodiukhin, M Iu; Zanochkin, A V; Terekhin, S V

    2013-01-01

    The article deals with a case report of successful hybrid surgical treatment of a patient presenting with a posttraumatic large false saccular aneurysm of the aortic arch with mediastinal displacement and compression of the left recurrent laryngeal nerve and trachea. The patient was subjected to a hybrid operation, i. e., bypass grafting of the brachiocephalic trunk and the left common carotid artery with a bifurcation prosthesis from the ascending aorta through sternotomy, carotid-vertebral and carotid-subclavian bypass grafting on the left in a combination with endoprosthetic repair of the aortic arch with the stent graft Valiant Thoracic 40 × 224 mm (VAMF 4040c200TE) manufactured by the Medtronic Company. The postoperative period was uneventful followed by rather rapid rehabilitation of the patient. One month after the operation, the clinical state improved considerably. His voice restored virtually completely, and breathlessness disappeared. According to the findings of MSCT angiography, the aneurysmatic cavity is thrombosed, with the stent graft showing no evidence of either dislocation or endoleak. The bifurcation bypass graft is functioning. According to the data of duplex scanning, the anastomoses established on the neck are patent. PMID:23531669

  9. Microsurgical cerebral aneurysm training porcine model

    Directory of Open Access Journals (Sweden)

    Jon Olabe

    2011-01-01

    Full Text Available The authors developed a simple reproducible technique for aneurysm creation and adapted it to mimic intracranial dissection conditions using glue application as a pseudo-arachnoid type layer. Ten 1-2-month-old healthy domestic swine were employed under general anesthesia. A novel technique for bifurcation aneurysm creation was developed using two arteries and a vein. After aneurysm creation, diluted sulfuric acid was applied on the dome with a micropipette to increase aneurysm fragility in selected zones. The surgical field was then dried and contact glue was applied around the vascular complex in a circular manner so as to emulate arachnoidal connection fibers. Microsurgical dissection of the aneurysm and surrounding vessels was performed by delicately removing the adhesive substance. Diverse aneurysm clipping techniques, emergency rupture situations and vascular reconstruction procedures were trained. Twenty-two aneurysms were created at several vascular sites, one aneurysm dome ruptured during application of sulfuric acid, two aneurysm models were proved to be thrombosed, two aneurysms ruptured during the dissection and no intraoperative deaths occurred. All aneurysms were clipped in an acceptable manner. This bifurcation aneurysm model provides a novel training system to be used not only by neurosurgeons but also by neurovascular interventionists.

  10. Modelling subset multivariate ARCH model via the AIC principle

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper we consider the problem of identifying a parsimonious subset multivariate ARCH model based on the AIC principle. The proposed approach can reduce the number of parameters in the final ARCH specification and allows for non-constant correlations between the components. Some simulation results illustrate the viability of the proposed procedure.

  11. A Functional Version of the ARCH Model

    CERN Document Server

    Hormann, Siegfried; Reeder, Ron

    2011-01-01

    Improvements in data acquisition and processing techniques have lead to an almost continuous flow of information for financial data. High resolution tick data are available and can be quite conveniently described by a continuous time process. It is therefore natural to ask for possible extensions of financial time series models to a functional setup. In this paper we propose a functional version of the popular ARCH model. We will establish conditions for the existence of a strictly stationary solution, derive weak dependence and moment conditions, show consistency of the estimators and perform a small empirical study demonstrating how our model matches with real data.

  12. Giant aortic arch aneurysm complicating Kawasaki disease: an original case report

    OpenAIRE

    Kaouthar, Hakim; Rafik, Boussaada; Jihen, Ayari; Imen, Hamdi; Lilia, Chaker; Fatma, Ouarda; Hela, Msaad

    2013-01-01

    Kawasaki disease (KD) is a common acute vasculitis in pediatric population that usually involves small and middle-sized arteries, commonly coronary arteries. Although the incidence and natural course of coronary aneurysms after KD are well documented, related reports on peripheral arterial and aortic aneurysms are scarce.

  13. A novel arterial pouch model of saccular aneurysm by concomitant elastase and collagenase digestion

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Background: An ideal aneurysm model of cerebral aneurysm is of great importance for studying the pathogenesis of the lesion and testing new techniques for diagnosis and treatment. Several models have been created in rabbits and are now widely used in experimental studies; however, every model has certain intrinsic limitations. Here we report the development of a novel saccular aneurysm model in rabbits using an arterial pouch that is subject to in vitro pre-digestion with combined elastase and collagenase. Methods: A segment of right common carotid artery (CCA) was dissected out and treated with elastase (60 U/ml, 20 min) followed by type I collagenase (1 mg/ml, 15 min) in vitro. The graft was anastomosed to an arterial arch built with the left CCA and the remaining right CCA, while the other end of the graft was ligated. The dimension and tissue structure of the pouch were analysed immediately, 2 or 8 weeks after operation. Findings: Ten terminal aneurysms were produced. The gross morphology of the aneurysm resembles the human cerebral terminal aneurysms. We have observed the following pathological changes:(1) growth of the aneurysm (mean diameter increased from (2.0±0.1) to (3.2±0.3) mm at 2 weeks, P<0.001, n=7~10); (2) thinning of the aneurysmal wall (the mean wall thickness decreased to 44% at 2 weeks), which was accompanied by significant losses of elastic fibres, collagen and the cellular component; and (3) spontaneous rupture (3 out of 9, one aneurysm ruptured 24 h after operation with the other two at 2 and 4 weeks respectively). Conclusion: This rabbit arterial pouch model mimics human cerebral aneurysms in relation to morphology and histology. In particular, this model exhibited an increased tendency of spontaneous rupture.

  14. Level-ARCH Short Rate Models with Regime Switching

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    This paper introduces regime switching volatility into level- ARCH models for the short rates of the US, the UK, and Germany. Once regime switching and level effects are included there are no gains from including ARCH effects. It is of secondary importance exactly how the regime switching...

  15. MODELING EXCHANGE RATES USING ARCH FAMILY OF MODELS

    Directory of Open Access Journals (Sweden)

    Ştefan Cristian CIUCU

    2016-06-01

    Full Text Available In this study, after a brief literature review, the RON / EURO exchange rate time series over the 03.01.2005 - 05.02.2015 time period is analyzed. After checking the stationarity of the data - ARCH, GARCH, EGARCH and TARCH models will be developed and compared. Next the best model is chosen and the serial correlation and the Jarque-Bera test are further analyzed with various conclusions being drawn.

  16. Game model of safety monitoring for arch dam deformation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Arch dam deformation is comprehensively affected by water pressure,temperature,dam’s structural behavior and material properties as well as other factors.Among them the water pressure and temperature are external factors(source factors) that cause dam deformation,and dam’s structural behavior and material properties are the internal factors of deformation(resistance factors).The dam deformation is the result of the mutual game playing between source factors and resistance factors.Therefore,resistance factors of structure and materials that reflect resistance character of arch dam structure are introduced into the traditional model,where structure factor is embodied by the flexibility coefficient of dam body and the maximum dam height,and material property is embodied by the elastic modulus of dam.On the basis of analyzing the correlation between dam deformation and resistance factors,the game model of safety monitoring for arch dam deformation is put forward.

  17. Endovascular treatment of aortic arch aneurysms Tratamento endovascular dos aneurismas de arco aórtico

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    Roberto Chiesa

    2008-06-01

    Full Text Available BACKGROUND: Endovascular approach to the aortic arch is an appealing solution for selected patients. OBJECTIVE: To compare the technical and clinical success recorded in the different anatomical settings of endografting for aortic arch disease. METHODS: Between June 1999 and October 2006, among 178 patients treated at our institution for thoracic aorta disease with a stent-graft, the aortic arch was involved in 64 cases. According to the classification proposed by Ishimaru, aortic zone 0 was involved in 14 cases, zone 1 in 12 cases and zone 2 in 38 cases. A hybrid surgical procedure of supra-aortic debranching and revascularization was performed in 37 cases. RESULTS: Zone 0. Proximal neck length: 44±6 mm. Initial clinical success was 78.6%: two deaths (stroke, one type Ia endoleak. At a mean follow-up of 16.4±11 months the midterm clinical success was 85.7%. Zone 1. Proximal neck length: 28±5 mm. Initial clinical success was 66.7%: 0 deaths, four type Ia endoleaks. At a mean follow-up of 16.9±17.2 months the midterm clinical success was 75.0%. Zone 2. Proximal neck length: 30±5 mm. Initial clinical success was 84.2%: two deaths (one cardiac arrest, one multiorgan embolization, three type Ia endoleaks, one case of open conversion. Two cases of delayed transitory paraparesis/paraplegia were observed. At a mean follow-up of 28.0±17.2 months the midterm clinical success was 89.5%. CONCLUSIONS: This study and a literature review demonstrated that hybrid procedure for aortic arch pathology is feasible in selected patients at high risk for conventional surgery. Our experience is still limited by the relatively small sample size. We propose to reserve zone 1 for patients unfit for sternotomy or in cases with aortic neck length > 30 mm following left common carotid artery debranching. We recommend to perform complete aortic rerouting of the aortic arch in cases with lesser comorbidities and shorter aortic neck.CONTEXTO: O tratamento endovascular

  18. The NIG-S&ARCH Model

    DEFF Research Database (Denmark)

    Jensen, Morten Berg; Lunde, Asger

    2001-01-01

    This paper examines the capabilities of the Normal Inverse Gaussian distribution as a model for stock returns. We extend the model of Barndorff-Nielsen (1997) to allow for a richer volatility structure and compare with the existing GARCH-type models. We conclude that the proportional model...... outperforms some of the most praised GARCH-M models. In particular, we make a big gain in modelling the skewness of equity returns...

  19. Modelling autogenous expansion for magnesia concrete in arch dams

    Institute of Scientific and Technical Information of China (English)

    Feng JIN; Guoxin ZHANG; Xiaoqing LUO; Chuhan ZHANG

    2008-01-01

    Magnesia Concrete is a kind of expansive con-crete used in Chinese hydraulic engineering more and more widely. To evaluate the effects of autogenous expan-sion on the stresses of arch dams, a simple model of auto-genous expansion for Magnesia Concrete in dam engineering is presented. This model is based on three assumptions: 1) the total amount of autogenous expan-sion of Magnesia Concrete is related only to the properties of materials and mixing of concrete; 2) the autogenous expansion of Magnesia Concrete is irreversible due to the irreversibility of hydration reaction of Magnesia in the concrete; 3) the autogenous expansion strain rates of Magnesia Concrete bear a relation between temperature and residual Magnesia per unit volume of concrete. The model is verified by some experimental data of autogen-ous expansion of Magnesia Concrete and field-measured data of an arch dam in China. Embedded into finite ele-ment arch dam simulation software, this model is employed to simulate the effects of autogenous expansion of Magnesia Concrete in hydraulic engineering.

  20. Two ARCH Models and Their Limitations as Diffusion Processes

    Institute of Scientific and Technical Information of China (English)

    杨海波; 叶俊

    2002-01-01

    Two typical ARCH models: the ASDARCH model and the APARCH model are analyzed. Let Yk and σ2k denote the log returns and the volatility. When the time interval h goes to zero, (Yk,σ2k), as a discrete time Markov chain system, weakly converges to a continuous time diffusion process. The continuous time approximation of the ASDARCH model is done using two different methods. With some transformation, these two results are equivalent to high frequency data. The continuous time approximation of the APARCH model is obtained by a different procedure.

  1. PREDICTIVE CAPACITY OF ARCH FAMILY MODELS

    Directory of Open Access Journals (Sweden)

    Raphael Silveira Amaro

    2016-03-01

    Full Text Available In the last decades, a remarkable number of models, variants from the Autoregressive Conditional Heteroscedastic family, have been developed and empirically tested, making extremely complex the process of choosing a particular model. This research aim to compare the predictive capacity, using the Model Confidence Set procedure, than five conditional heteroskedasticity models, considering eight different statistical probability distributions. The financial series which were used refers to the log-return series of the Bovespa index and the Dow Jones Industrial Index in the period between 27 October 2008 and 30 December 2014. The empirical evidences showed that, in general, competing models have a great homogeneity to make predictions, either for a stock market of a developed country or for a stock market of a developing country. An equivalent result can be inferred for the statistical probability distributions that were used.

  2. Aneurysm flow characteristics in realistic carotid artery aneurysm models induced by proximal virtual stenotic plaques: a computational hemodynamics study

    Science.gov (United States)

    Castro, Marcelo A.; Peloc, Nora L.; Chien, Aichi; Goldberg, Ezequiel; Putman, Christopher M.; Cebral, Juan R.

    2015-03-01

    Cerebral aneurysms may rarely coexist with a proximal artery stenosis. In that small percent of patients, such coexistence poses a challenge for interventional neuroradiologists and neurosurgeons to make the best treatment decision. According to previous studies, the incidence of cerebral aneurysms in patients with internal carotid artery stenosis is no greater than five percent, where the aneurysm is usually incidentally detected, being about two percent for aneurysms and stenoses in the same cerebral circulation. Those cases pose a difficult management decision for the physician. Case reports showed patients who died due to aneurysm rupture months after endarterectomy but before aneurysm clipping, while others did not show any change in the aneurysm after plaque removal, having optimum outcome after aneurysm coiling. The aim of this study is to investigate the intra-aneurysmal hemodynamic changes before and after treatment of stenotic plaque. Virtually created moderate stenoses in vascular models of internal carotid artery aneurysm patients were considered in a number of cases reconstructed from three dimensional rotational angiography images. The strategy to create those plaques was based on parameters analyzed in a previous work where idealized models were considered, including relative distance and stenosis grade. Ipsilateral and contralateral plaques were modeled. Wall shear stress and velocity pattern were computed from finite element pulsatile blood flow simulations. The results may suggest that wall shear stress changes depend on relative angular position between the aneurysm and the plaque.

  3. The murine angiotensin II-induced abdominal aortic aneurysm model: rupture risk and inflammatory progression patterns

    Directory of Open Access Journals (Sweden)

    Richard Y Cao

    2010-07-01

    Full Text Available An abdominal aortic aneurysm (AAA is an enlargement of the greatest artery in the body defined as an increase in diameter of 1.5-fold. AAAs are common in the elderly population and thousands die each year from their complications. The most commonly used mouse model to study the pathogenesis of AAA is the angiotensin II (Ang II infusion method delivered via osmotic mini-pump for 28 days. Here, we studied the site-specificity and onset of aortic rupture, characterized three-dimensional (3D images and flow patterns in developing AAAs by ultrasound imaging, and examined macrophage infiltration in the Ang II model using 65 apolipoprotein E deficient mice. Aortic rupture occurred in 16 mice (25 % and was nearly as prevalent at the aortic arch (44 % as it was in the suprarenal region (56 % and was most common within the first seven days after Ang II infusion (12 of 16; 75 %. Longitudinal ultrasound screening was found to correlate nicely with histological analysis and AAA volume renderings showed a significant relationship with AAA severity index. Aortic dissection preceded altered flow patterns and macrophage infiltration was a prominent characteristic of developing AAAs. Targeting the inflammatory component of AAA disease with novel therapeutics will hopefully lead to new strategies to attenuate aneurysm growth and aortic rupture.

  4. The Comparison of Different Degree of Convexity and 3D Modeling of Involute Hyperbolic Arch Dam

    Institute of Scientific and Technical Information of China (English)

    DU Qi-lu; DU Ting-na; ZHAO Hai-feng

    2011-01-01

    Because of good quality of compressive resistance, the hyperbolic arch dam is being increasingly applied to engineering projects. In order to satisfy the needs of compressive resistance under the conditions of high water pressure, a stress analysis is required for the dam. During the stress analysis process however, due to the complexity of the three-dimensional modeling, it is very hard to form a model. Therefore, the stress analysis process is a barrier for the arch dam. In this article, based on the research of the new line-type arch dam, a mathematical model in different degree of convexity conditions of the dam is established; using the C + + language program, a computer three-dimensional model simulation is realized on AutoCAD. The accurate three-dimensional model is providing a finite element optimization design of the involute hyperbolic arch dam for the next step.

  5. The preparation of aneurysm model in rabbits by vessel ligation and elastase-induced technique

    International Nuclear Information System (INIS)

    Objective: To establish an aneurysm model, which is quite similar to the human intracranial aneurysm in morphology, in rabbits by means of vessel ligation together with elastase-induced technique. Methods: Sixteen New Zealand white rabbits were used in this study. Distal carotid ligation and intraluminal elastase incubation was employed in ten rabbits (study group) to create aneurysm on the right common carotid artery. And surgical suture of a segment of the left carotid common artery was carried out in six rabbits (used as control group) to establish the aneurysm model. DSA exam of the created aneurysms by using catheterization via femoral artery was performed at one week and at one month after surgery. The patency, morphology and pathology of the aneurysms were observed. The results were statistically analyzed. Results: The aneurysms in both groups remained patent after they were created. Angiography one week after the surgery showed that all the aneurysms in study group were patent, while in control group only two aneurysms showed opacification with contrast medium and the remaining four aneurysms were all occluded. DSA at one month after the procedure demonstrated that all the aneurysms in study group remained patent, and the previous two patent aneurysms in control group became occluded. The mean width and length of the aneurysmal cavity in study group immediately after the procedure were (3.70 ± 0.16) mm and (6.53 ± 0.65) mm respectively, which enlarged to (5.06 ± 0.31) mm and (9.0 ± 0.52) mm respectively one month after the surgery. The difference in size changes was statistically significant (P < 0.05). Pathologically, almost complete absence of the internal elastic lamina and medial wall elastin of the aneurysms was observed. Conclusion: The aneurysm model prepared with vessel ligation together with elastase-induced technique carries high patent rate and possesses the feature of spontaneous growing, moreover, its morphology is quite similar to the

  6. MEASURED MODEL, THEORETICAL MODEL AND REPRESENTED MODEL: THE SO-CALLED ARCH OF DRUSUS IN ROME

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    M. Canciani

    2012-09-01

    Full Text Available The Arch of Drusus is a complex building, stratified over time. It isn’t possible to advance only one hypothesis about its origin, but its several transformations may be given some interpretations. The difficulty lies in the coexistence of two structures, typologically and chronologically different, in a single monument: an original structure which can be related to a commemorative travertine arch sheathed in marble, dating back to the Imperial Age, which probably had three fornices and a later structure reused in the III century as an aque- duct arch and monumentalized again with the application of decorated architectural elements on the southern façade. In order to provide a graphic description as much accurate as possible from the metric-dimensional point of view and as much detailed as possible in all the elements which form the building, a new survey methodology has been tested. It uses different kinds of systems – instrumental, topographic and GPS, photogrammetric and direct traditional – which complement each other, in order to render a three-dimensional computerized reference model. The analysis process of the monument, made from what emerged from the archaeological analysis, thanks to the carrying out of dif- ferent navigable models, has been developed making, in the early stage, a represented model subsequently detailed on the basis of the incongruities detected in the survey.

  7. Stationarity and geometric ergodicity of a class of nonlinear ARCH models

    OpenAIRE

    Saidi, Youssef; Zakoian, Jean-Michel

    2006-01-01

    A class of nonlinear ARCH processes is introduced and studied. The existence of a strictly stationary and $\\beta$-mixing solution is established under a mild assumption on the density of the underlying independent process. We give sufficient conditions for the existence of moments. The analysis relies on Markov chain theory. The model generalizes some important features of standard ARCH models and is amenable to further analysis.

  8. Analysis of the pedestrian arching at bottleneck based on a bypassing behavior model

    Science.gov (United States)

    Tang, Ming; Jia, Hongfei; Ran, Bin; Li, Jun

    2016-07-01

    A bypassing behavior model was proposed, in which the local optimal decision behavior in the strategy level was modeled in velocity-time domain, to describe how pedestrians bypass the local obstacles considering the relative speed. The model contains (1) pedestrian visual and contact information acquisition; (2) motion state prediction of the local obstacles based on the visual and contact information; (3) pedestrian bypass strategy modeling in the velocity-time domain; (4) moving and overlapping solution. In the numerical solution, velocity domain was divided into n equal angle, the value of n ranges from 2 to infinity, the Manhattan space was refined gradually to Euclid Space accordingly, in which the movement of pedestrians was described. The model was applied to the analysis of pedestrian arching at the bottleneck in the emergent evacuation situation. (1) The results showed that the formation of the pedestrian arching at the bottleneck was deformation pressure, because many pedestrians try to pass through the bottleneck simultaneously, even in the absence of friction, the pedestrian arching still occurs; (2) In the emergent situation, we are more concerned about the bottleneck attribution of resistance to form the arching, the calculation and simulation results showed that the probability of an arching and the bottleneck width is an exponential function relationship, so when the stampede occurs in the middle of the bottleneck, the probability of arching will increase exponentially.

  9. ARCH and GARCH Models vs. Martingale Volatility of Finance Market Returns

    OpenAIRE

    Joseph L. McCauley

    2008-01-01

    ARCH and GARCH models assume either i.i.d. or (what economists lable as) white noise as is usual in regression analysis while assuming memory in a conditional mean square fluctuation with stationary increments. We will show that ARCH/GARCH is inconsistent with uncorrelated increments, violating the i.i.d. and white assumptions and finance data and the efficient market hypothesis as well.

  10. Dental arch changes associated with rapid maxillary expansion: A retrospective model analysis study

    Directory of Open Access Journals (Sweden)

    Ivor M D′Souza

    2015-01-01

    Full Text Available Introduction: Transverse deficiency of the maxilla is a common clinical problem in orthodontics and dentofacial orthopedics. Transverse maxillary deficiency, isolated or associated with other dentofacial deformities, results in esthetic and functional impairment giving rise to several clinical manifestations such as asymmetrical facial growth, positional and functional mandibular deviations, altered dentofacial esthetics, adverse periodontal responses, unstable dental tipping, and other functional problems. Orthopedic maxillary expansion is the preferred treatment approach to increase the maxillary transverse dimension in young patients by splitting of the mid palatal suture. This orthopedic procedure has lately been subject of renewed interest in orthodontic treatment mechanics because of its potential for increasing arch perimeter to alleviate crowding in the maxillary arch without adversely affecting facial profile. Hence, the present investigation was conducted to establish a correlation between transverse expansion and changes in the arch perimeter, arch width and arch length. Methods: For this purpose, 10 subjects (five males, five females were selected who had been treated by rapid maxillary expansion (RME using hyrax rapid palatal expander followed by fixed mechanotherapy (PEA. Pretreatment (T1, postexpansion (T2, and posttreatment (T3 dental models were compared for dental changes brought about by RME treatment and its stability at the end of fixed mechanotherapy. After model measurements were made, the changes between T1-T2, T2-T3 and T1-T3 were determined for each patient. The mean difference between T1-T2, T2-T3 and T1-T3 were compared to assess the effects of RME on dental arch measurements. Results are expressed as mean ± standard deviation and are compared by repeated measures analysis of variance followed by a post-hoc test. Arch perimeter changes are correlated with changes in arch widths at the canine, premolar and molar

  11. Quasi-MLE for quadratic ARCH model with long memory

    OpenAIRE

    Grublytė, Ieva; Surgailis, Donatas; Škarnulis, Andrius

    2015-01-01

    We discuss parametric quasi-maximum likelihood estimation for quadratic ARCH process with long memory introduced in Doukhan et al. (2015) and Grublyt\\.e and \\v{S}karnulis (2015) with conditional variance given by a strictly positive quadratic form of observable stationary sequence. We prove consistency and asymptotic normality of the corresponding QMLE estimates, including the estimate of long memory parameter $0< d < 1/2$. A simulation study of empirical MSE is included.

  12. Endovascular Broad-Neck Aneurysm Creation in a Porcine Model Using a Vascular Plug

    International Nuclear Information System (INIS)

    Ruptured cerebral arterial aneurysms require prompt treatment by either surgical clipping or endovascular coiling. Training for these sophisticated endovascular procedures is essential and ideally performed in animals before their use in humans. Simulators and established animal models have shown drawbacks with respect to degree of reality, size of the animal model and aneurysm, or time and effort needed for aneurysm creation. We therefore aimed to establish a realistic and readily available aneurysm model. Five anticoagulated domestic pigs underwent endovascular intervention through right femoral access. A total of 12 broad-neck aneurysms were created in the carotid, subclavian, and renal arteries using the Amplatzer vascular plug. With dedicated vessel selection, cubic, tubular, and side-branch aneurysms could be created. Three of the 12 implanted occluders, two of them implanted over a side branch of the main vessel, did not induce complete vessel occlusion. However, all aneurysms remained free of intraluminal thrombus formation and were available for embolization training during a surveillance period of 6 h. Two aneurysms underwent successful exemplary treatment: one was stent-assisted, and one was performed with conventional endovascular coil embolization. The new porcine aneurysm model proved to be a straightforward approach that offers a wide range of training and scientific applications that might help further improve endovascular coil embolization therapy in patients with cerebral aneurysms.

  13. Modeling and forecasting crude oil markets using ARCH-type models

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chin Wen [Research Centre of Mathematical Sciences, Faculty of Information Technology, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia)

    2009-06-15

    This study investigates the time-varying volatility of two major crude oil markets, the West Texas Intermediate (WTI) and Europe Brent. A flexible autoregressive conditional heteroskedasticity (ARCH) model is used to take into account the stylized volatility facts such as clustering volatility, asymmetric news impact and long memory volatility among others. The empirical results indicate that the intensity of long-persistence volatility in the WTI is greater than in the Brent. It is also found that for the WTI, the appreciation and depreciation shocks of the WTI have similar impact on the resulting volatility. However, a leverage effect is found in Brent. Although both the estimation and diagnostic evaluations are in favor of an asymmetric long memory ARCH model, only the WTI models provide superior in the out-of-sample forecasts. On the other hand, from the empirical out-of-sample forecasts, it appears that the simplest parsimonious generalized ARCH provides the best forecasted evaluations for the Brent crude oil data. (author)

  14. Modeling and forecasting crude oil markets using ARCH-type models

    International Nuclear Information System (INIS)

    This study investigates the time-varying volatility of two major crude oil markets, the West Texas Intermediate (WTI) and Europe Brent. A flexible autoregressive conditional heteroskedasticity (ARCH) model is used to take into account the stylized volatility facts such as clustering volatility, asymmetric news impact and long memory volatility among others. The empirical results indicate that the intensity of long-persistence volatility in the WTI is greater than in the Brent. It is also found that for the WTI, the appreciation and depreciation shocks of the WTI have similar impact on the resulting volatility. However, a leverage effect is found in Brent. Although both the estimation and diagnostic evaluations are in favor of an asymmetric long memory ARCH model, only the WTI models provide superior in the out-of-sample forecasts. On the other hand, from the empirical out-of-sample forecasts, it appears that the simplest parsimonious generalized ARCH provides the best forecasted evaluations for the Brent crude oil data. (author)

  15. Characterization of the transport topology in patient-specific abdominal aortic aneurysm models

    Science.gov (United States)

    Arzani, Amirhossein; Shadden, Shawn C.

    2012-08-01

    Abdominal aortic aneurysm (AAA) is characterized by disturbed blood flow patterns that are hypothesized to contribute to disease progression. The transport topology in six patient-specific abdominal aortic aneurysms was studied. Velocity data were obtained by image-based computational fluid dynamics modeling, with magnetic resonance imaging providing the necessary simulation parameters. Finite-time Lyapunov exponent (FTLE) fields were computed from the velocity data, and used to identify Lagrangian coherent structures (LCS). The combination of FTLE fields and LCS was used to characterize topological flow features such as separation zones, vortex transport, mixing regions, and flow impingement. These measures offer a novel perspective into AAA flow. It was observed that all aneurysms exhibited coherent vortex formation at the proximal segment of the aneurysm. The evolution of the systolic vortex strongly influences the flow topology in the aneurysm. It was difficult to predict the vortex dynamics from the aneurysm morphology, motivating the application of image-based flow modeling.

  16. FSI and CFD Modeling of Cerebral Aneurysm Model and Comparing to PIV Experiments

    Science.gov (United States)

    Wang, Zhaopeng; Hao, Qing

    2014-11-01

    Wall shear stress or strain is considered as an important factor for cerebral aneurysm growth and even rupture. The objective of present study is to evaluate wall shear stress in aneurysm sac and neck by Fluid Structure Interaction (FSI) and solid wall Computational Fluid Dynamics (CFD) approaches and compare the simulation results against Particle Image Velocimetry (PIV) experimental data from an elastic in vitro aneurysm model. The FSI and CFD simulation results showed that both approaches captured the flow patterns inside the aneurysm sac under pulsatile flow, that in diastole time period the flow inside the aneurysm sac was a stable circular clock-wise flow; when higher velocity entered into the aneurysm sac during systole and in a short diastole time period an anti-clock circular flow pattern emerged near the distal neck. Both approaches showed that the shear stress near the proximal neck experienced higher shear stress than the distal neck, while in the aneurysm dome the shear stress was always the lowest. In this study, we also showed that shear stress values at proximal neck and distal neck from FSI approach were lower than solid wall CFD approach.

  17. Properties of some statistics for AR-ARCH model with application to technical analysis

    Science.gov (United States)

    Huang, Xudong; Liu, Wei

    2009-03-01

    In this paper, we investigate some popular technical analysis indexes for AR-ARCH model as real stock market. Under the given conditions, we show that the corresponding statistics are asymptotically stationary and the law of large numbers hold for frequencies of the stock prices falling out normal scope of these technical analysis indexes under AR-ARCH, and give the rate of convergence in the case of nonstationary initial values, which give a mathematical rationale for these methods of technical analysis in supervising the security trends.

  18. Variations among the primary maxillary dental arch forms using a polynominal equation model.

    Science.gov (United States)

    Tsai, Hung-Huey

    2003-01-01

    This study identifies arch symmetry and describes arch form variations in normal primary maxillary dental casts. Sixty-two percent of casts had asymmetrical arches, and 38% had symmetrical arches. Six types of arch form were identified according to the ratio of arch width to length. There were more long types than short types. The rounded and short types tended to have a more-symmetrical arch than did the long type. PMID:12739689

  19. COMPARISON OF CELLULOSE ACETATE POLYMER AND ELECTROLYTIC DETACHABLE COILS FOR TREATMENT OF CANINE ANEURYSMAL MODELS

    Institute of Scientific and Technical Information of China (English)

    杨新健; 吴中学; 李佑祥; 孙异临; 尹可

    2002-01-01

    Objective.Electrolytic detachable coils (EDC) have been the main embolic materials for intracranial aneurysms.Liquid aneurysmal embolic materials represented by cellulose acetate polymer (CAP) are still in controversy.In this research,the embolization results and pathological reactions after embolization of canine aneurysmal models with EDC or CAP were observed and compared. Methods.The canine aneurysmal models constructed by anastomosis of venous pouches were randomly grouped.The aneurysms were respectively occluded with CAP and electrolytic detachable coils that was named by Wu electrolytic detachable coil (WEDC) and made by us.Angiogram follow ups were performed at 24 hour,2 week,and 2 month after embolization.The occluded aneurysms were dissected in each stage for light microscopic,electron microscopic,and histochemical research. Results.The effect of embolization was significantly better with WEDC than that with CAP ( χ 2=5.56,P< 0.05) .Post embolized complications such as aneurysm rupture and stenosis of parent arteries could only be found in CAP group.Pathological research showed that CAP mass could packed the aneurysms more densely than coils.Acute chemical damage of aneurysmal wall and inflammatory cell infiltration was prominently found in early stage after CAP embolization.Organization of thrombus inside aneurysms and formation of endothelial tissue over the orifices of aneurysmal necks could be found in both groups 2 months after embolization.But parts of coils might be exposed outside endothelial layer. Conclusions.EDC are still the most safe,efficient,and reliable instruments to embolize aneurysm.CAP should be improved further to solve the problem of strong chemical corrosion and difficulty in control before it is widely used.

  20. Estimation and asymptotic inference in the first order AR-ARCH model

    DEFF Research Database (Denmark)

    Lange, Theis; Rahbek, Anders; Jensen, Søren Tolver

    2011-01-01

    This article studies asymptotic properties of the quasi-maximum likelihood estimator (QMLE) for the parameters in the autoregressive (AR) model with autoregressive conditional heteroskedastic (ARCH) errors. A modified QMLE (MQMLE) is also studied. This estimator is based on truncation of individual...

  1. Quantitative comparison of hemodynamics in simulated and 3D angiography models of cerebral aneurysms by use of computational fluid dynamics.

    Science.gov (United States)

    Saho, Tatsunori; Onishi, Hideo

    2015-07-01

    In this study, we evaluated hemodynamics using simulated models and determined how cerebral aneurysms develop in simulated and patient-specific models based on medical images. Computational fluid dynamics (CFD) was analyzed by use of OpenFOAM software. Flow velocity, stream line, and wall shear stress (WSS) were evaluated in a simulated model aneurysm with known geometry and in a three-dimensional angiographic model. The ratio of WSS at the aneurysm compared with that at the basilar artery was 1:10 in simulated model aneurysms with a diameter of 10 mm and 1:18 in the angiographic model, indicating similar tendencies. Vortex flow occurred in both model aneurysms, and the WSS decreased in larger model aneurysms. The angiographic model provided accurate CFD information, and the tendencies of simulated and angiographic models were similar. These findings indicate that hemodynamic effects are involved in the development of aneurysms. PMID:25911446

  2. Animal Models Used to Explore Abdominal Aortic Aneurysms

    DEFF Research Database (Denmark)

    Lysgaard Poulsen, J; Stubbe, J; Lindholt, J S

    2016-01-01

    OBJECTIVE: Experimental animal models have been used to investigate the formation, development, and progression of abdominal aortic aneurysms (AAAs) for decades. New models are constantly being developed to imitate the mechanisms of human AAAs and to identify treatments that are less risky than...... those used today. However, to the authors' knowledge, there is no model identical to the human AAA. The objective of this systematic review was to assess the different types of animal models used to investigate the development, progression, and treatment of AAA and to highlight their advantages...... and limitations. METHODS: A search protocol was used to perform a systematic literature search of PubMed and Embase. A total of 2,830 records were identified. After selection of the relevant articles, 564 papers on animal AAA models were included. RESULTS: The most common models in rodents, including elastase...

  3. ARCH模型的诊断分析%Diagnose analysis in ARCH models

    Institute of Scientific and Technical Information of China (English)

    柯珂; 张世英

    2001-01-01

    探讨了ARCH模型的诊断分析和变结构建模问题.所提出的分整增广GARCH-M模型包括了几乎所有现有的ARCH模型,基于分整增广GARCH-M模型克服了ARCH模型在模型设定检验,长记忆检验和参数估计等方面的障碍.利用分段建模方法来检测模型结构变化点和分段变化模型的选择.最后,以上海证券综合事业股票指数为数据,验证了诊断分析方法的有效性.%The diagnose analysis and modeling problem with structure changein ARCH models are discussed in this paper.The paper proposses fractional integrated augmented GARCH-M model which can embrace almost all the current ARCH models. Based on the fractional integrated augmented GARCH-M model, the handicap in model specification test, long memory test and parameters estimation is oversome.The segment-modeling method is used to detect the structure changing points of the ARCH model and test the models for segment-changing models.Finally, with the composite index of closing price in Shanghai stock market, it is shown to illustrate the effectiveness of the diagnose analysis.

  4. A Thrombus Generation Model Applied to Aneurysms Treated with Shape Memory Polymer Foam and Metal Coils

    Science.gov (United States)

    Horn, John; Ortega, Jason; Hartman, Jonathan; Maitland, Duncan

    2015-11-01

    To prevent their rupture, intracranial aneurysms are often treated with endovascular metal coils which fill the aneurysm sac and isolate it from the arterial flow. Despite its widespread use, this method can result in suboptimal outcomes leading to aneurysm recurrence. Recently, shape memory polymer foam has been proposed as an alternative aneurysm filler. In this work, a computational model has been developed to predict thrombus formation in blood in response to such cardiovascular implantable devices. The model couples biofluid and biochemical phenomena present as the blood interacts with a device and stimulates thrombus formation. This model is applied to simulations of both metal coil and shape memory polymer foam treatments within an idealized 2D aneurysm geometry. Using the predicted thrombus responses, the performance of these treatments is evaluated and compared. The results suggest that foam-treated aneurysms may fill more quickly and more completely with thrombus than coil-filled aneurysms, potentially leading to improved long-term aneurysm healing. This work was performed in part under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  5. Hybrid surgical management of a patient with an aneurysm of the arch and descending portion of the right-sided aorta combined with type B dissection and decompensated tracheal stenosis.

    Science.gov (United States)

    Belov, Yu V; Abugov, S A; Komarov, R N; Puretskiĭ, M V; Stepanenko, A B; Stogniĭ, N Yu; Magamadov, Ya U

    2011-01-01

    The right-sided aorta is a rare congenital abnormality of the cardiovascular system encountered in 0.05-0.1% of cases during roentgenological examinations and in 0.04-0.1% of cases of autopsy series. Given utterly low prevalence of this pathology, we considered it wise to present herein our own case report dealing with hybrid surgical management of a patient suffering from an aneurysm of both the arch and descending portion of the right-sided aorta combined with type B dissection thereof and decompensated tracheal stenosis. The first stage of the operation consisted in prosthetic repair of the distal third of the arch and the descending portion of the aorta with the "Vascutek" stent graft 20 mm with type 1 haemodynamical correction (i. e., re-establishing the blood flow into the true channel in the zone of the distal anastomosis) in the conditions of extracorporeal circulation (EC) and bihemispheric antegrade cerebral perfusion ACP, followed by replantation of the left subclavian artery ostium into the left common carotid artery. An aneurysmal growth rate of more than 1 cm a year was considered an absolute indication for the second stage of correction of the aortic pathology concerned. The second stage included stenting of the thoracic portion of the aorta. The TF262C150X Valiant thoracic stent graft was implanted into the area of the distal anastomosis with a conduit, followed by positioning the TF 323C150X Valiant thoracic system inserted into the distal end of the first stent. The use of hybrid techniques (a combination of open and endovascular interventions) predetermined the success of surgical management of the patient presenting with dissection of the right-sided aorta. PMID:22616242

  6. Fast Virtual Stenting with Active Contour Models in Intracranical Aneurysm.

    Science.gov (United States)

    Zhong, Jingru; Long, Yunling; Yan, Huagang; Meng, Qianqian; Zhao, Jing; Zhang, Ying; Yang, Xinjian; Li, Haiyun

    2016-02-15

    Intracranial stents are becoming increasingly a useful option in the treatment of intracranial aneurysms (IAs). Image simulation of the releasing stent configuration together with computational fluid dynamics (CFD) simulation prior to intervention will help surgeons optimize intervention scheme. This paper proposed a fast virtual stenting of IAs based on active contour model (ACM) which was able to virtually release stents within any patient-specific shaped vessel and aneurysm models built on real medical image data. In this method, an initial stent mesh was generated along the centerline of the parent artery without the need for registration between the stent contour and the vessel. Additionally, the diameter of the initial stent volumetric mesh was set to the maximum inscribed sphere diameter of the parent artery to improve the stenting accuracy and save computational cost. At last, a novel criterion for terminating virtual stent expanding that was based on the collision detection of the axis aligned bounding boxes was applied, making the stent expansion free of edge effect. The experiment results of the virtual stenting and the corresponding CFD simulations exhibited the efficacy and accuracy of the ACM based method, which are valuable to intervention scheme selection and therapy plan confirmation.

  7. Finite element model for arch bridge vibration dynamics considering effect of suspender length adjustment on geometry stiffness matrix

    Institute of Scientific and Technical Information of China (English)

    ZHONG Yi-feng; WANG Rui; YING Xue-gang; CHEN Huai

    2006-01-01

    In this paper, we established a finite element (FEM) model to analyze the dynamic characteristics of arch bridges. In this model, the effects of adjustment to the length of a suspender on its geometry stiffness matrix are stressed. The FEM equations of mechanics characteristics, natural frequency and main mode are set up based on the first order matrix perturbation theory. Applicantion of the proposed model to analyze a real arch bridge proved the improvement in the simulation precision of dynamical characteristics of the arch bridge by considering the effects of suspender length variation.

  8. Density forecasts of crude-oil prices using option-implied and ARCH-type models

    DEFF Research Database (Denmark)

    Høg, Esben; Tsiaras, Leonicas

    2011-01-01

    The predictive accuracy of competing crude-oil price forecast densities is investigated for the 1994–2006 period. Moving beyond standard ARCH type models that rely exclusively on past returns, we examine the benefits of utilizing the forward-looking information that is embedded in the prices...... of derivative contracts. Risk-neutral densities, obtained from panels of crude-oil option prices, are adjusted to reflect real-world risks using either a parametric or a non-parametric calibration approach. The relative performance of the models is evaluated for the entire support of the density, as well...... obtained by option prices and non-parametric calibration methods over those constructed using historical returns and simulated ARCH processes. © 2010 Wiley Periodicals, Inc. Jrl Fut Mark...

  9. Density Forecasts of Crude-Oil Prices Using Option-Implied and ARCH-Type Models

    DEFF Research Database (Denmark)

    Tsiaras, Leonidas; Høg, Esben

      The predictive accuracy of competing crude-oil price forecast densities is investigated for the 1994-2006 period. Moving beyond standard ARCH models that rely exclusively on past returns, we examine the benefits of utilizing the forward-looking information that is embedded in the prices...... of derivative contracts. Risk-neutral densities, obtained from panels of crude-oil option prices, are adjusted to reflect real-world risks using either a parametric or a non-parametric calibration approach. The relative performance of the models is evaluated for the entire support of the density, as well...... obtained by option prices and non-parametric calibration methods over those constructed using historical returns and simulated ARCH processes....

  10. A quantitative method for defining high-arched palate using the Tcof1(+/-) mutant mouse as a model.

    Science.gov (United States)

    Conley, Zachary R; Hague, Molly; Kurosaka, Hiroshi; Dixon, Jill; Dixon, Michael J; Trainor, Paul A

    2016-07-15

    The palate functions as the roof of the mouth in mammals, separating the oral and nasal cavities. Its complex embryonic development and assembly poses unique susceptibilities to intrinsic and extrinsic disruptions. Such disruptions may cause failure of the developing palatal shelves to fuse along the midline resulting in a cleft. In other cases the palate may fuse at an arch, resulting in a vaulted oral cavity, termed high-arched palate. There are many models available for studying the pathogenesis of cleft palate but a relative paucity for high-arched palate. One condition exhibiting either cleft palate or high-arched palate is Treacher Collins syndrome, a congenital disorder characterized by numerous craniofacial anomalies. We quantitatively analyzed palatal perturbations in the Tcof1(+/-) mouse model of Treacher Collins syndrome, which phenocopies the condition in humans. We discovered that 46% of Tcof1(+/-) mutant embryos and new born pups exhibit either soft clefts or full clefts. In addition, 17% of Tcof1(+/-) mutants were found to exhibit high-arched palate, defined as two sigma above the corresponding wild-type population mean for height and angular based arch measurements. Furthermore, palatal shelf length and shelf width were decreased in all Tcof1(+/-) mutant embryos and pups compared to controls. Interestingly, these phenotypes were subsequently ameliorated through genetic inhibition of p53. The results of our study therefore provide a simple, reproducible and quantitative method for investigating models of high-arched palate.

  11. Blood flow dynamic improvement with aneurysm repair detected by a patient-specific model of multiple aortic aneurysms.

    Science.gov (United States)

    Sughimoto, Koichi; Takahara, Yoshiharu; Mogi, Kenji; Yamazaki, Kenji; Tsubota, Ken'ichi; Liang, Fuyou; Liu, Hao

    2014-05-01

    Aortic aneurysms may cause the turbulence of blood flow and result in the energy loss of the blood flow, while grafting of the dilated aorta may ameliorate these hemodynamic disturbances, contributing to the alleviation of the energy efficiency of blood flow delivery. However, evaluating of the energy efficiency of blood flow in an aortic aneurysm has been technically difficult to estimate and not comprehensively understood yet. We devised a multiscale computational biomechanical model, introducing novel flow indices, to investigate a single male patient with multiple aortic aneurysms. Preoperative levels of wall shear stress and oscillatory shear index (OSI) were elevated but declined after staged grafting procedures: OSI decreased from 0.280 to 0.257 (first operation) and 0.221 (second operation). Graftings may strategically counter the loss of efficient blood delivery to improve hemodynamics of the aorta. The energy efficiency of blood flow also improved postoperatively. Novel indices of pulsatile pressure index (PPI) and pulsatile energy loss index (PELI) were evaluated to characterize and quantify energy loss of pulsatile blood flow. Mean PPI decreased from 0.445 to 0.423 (first operation) and 0.359 (second operation), respectively; while the preoperative PELI of 0.986 dropped to 0.820 and 0.831. Graftings contributed not only to ameliorate wall shear stress or oscillatory shear index but also to improve efficient blood flow. This patient-specific modeling will help in analyzing the mechanism of aortic aneurysm formation and may play an important role in quantifying the energy efficiency or loss in blood delivery. PMID:23852404

  12. Deployment Accuracy of the Conformable GORE® TAG® Thoracic Endoprosthesis in the Treatment of Zones 2 and 3 Aortic Arch Aneurysms Compared with the Previous TAG®

    OpenAIRE

    Ito, Eisaku; Kanaoka, Yuji; Maeda, Koji; Ohta, Hiroki; ISHIDA, ATSUSHI; Ohki, Takao

    2015-01-01

    Purposes: When placing stent grafts, deployment accuracy and birdbeaking due to inadequate conformability and device apposition along the inner curvature of the arch have been encountered. The new Conformable GORE® TAG® Thoracic Endoprosthesis (CTAG) is designed to have enhanced compression resistance and improved conformability in difficult anatomy. The present study compared the deployment accuracy and conformability of the CTAG Device with TAG Device.

  13. 3D MODELLING OF PROPHYLACTIC FOOTWEAR FOR A HIGH ARCHED FOOT

    Directory of Open Access Journals (Sweden)

    COSTEA Mariana

    2016-05-01

    Full Text Available This article approaches the methodology of designing customized footwear for high arched foot. The authors propose to reconsider the classical structure of footwear bottom components for people with high arched foot and recommend incorporating custom components, with the role of compensation or adjustment. This study continues the authors’ research, starting from a foot’s 3D shape obtained by 3D scanning, the anthropometrical and biomechanical parameters, shoe lasts’ 3D modelling and continuing with 3D footwear design. Including customized orthosis can help to stop the evolution of abnormalities, diminishes sensations of pain during walking and improves performance in various physical activities carried out during the day, walking, running, and standing. The prophylactic footwear has to meet four main requirements: to protect the foot and ankle during walking and static; to ensure the normal resistance systems (bones, muscle and joint of the foot; to prevent the installation of irreversible structural changes by reducing stress on the foot; to contribute to increased performance in conducting regular physical activity. It is presented the steps of modelling an orthosis, a virtual simulation of its cutting process, followed by the integration and development of the insole, filling and sole for a customized shoe. Delcam Crispin CAD system and its applications for orthopaedics are used to design the bottom components of prophylactic footwear for a high arched foot.

  14. The use of silicone materials to model abdominal aortic aneurysm behaviour

    OpenAIRE

    Doyle, Barry J.; Callanan, Anthony; Corbett, Timothy J.; Cloonan, Aidan J.; O'Donnell, Michael R.; Vorp, David A.; McGloughlin, Timothy M

    2008-01-01

    peer-reviewed This paper aims to identify the rupture locations of abdominal aortic aneurysms. Dow Corning Sylgard 184 was mechanically characterised. Five idealised models were then manufactured using this silicone rubber which were subsequently inflated to rupture with the images recorded using a high speed camera. Four of the five models tested ruptured at inflection points in the proximal and distal regions of the aneurysm sac, and not at regions of maximum diameter. US National Hea...

  15. Tail dependence of random variables from ARCH and heavy tailed bilinear models

    Institute of Scientific and Technical Information of China (English)

    PAN; Jiazhu(潘家柱)

    2002-01-01

    Discussed in this paper is the dependent structure in the tails of distributions of random variables from some heavy-tailed stationary nonlinear time series. One class of models discussed is the first-order autoregressive conditional heteroscedastic (ARCH) process introduced by Engle (1982). The other class is the simple first-order bilinear models driven by heavy-tailed innovations. We give some explicit formulas for the asymptotic values of conditional probabilities used for measuring the tail dependence between two random variables from these models. Our results have significant meanings in finance.

  16. GEOTECHNICAL MODELS OF THE ARCH FOUNDATIONS OF THE MASLENICA BRIDGE

    Directory of Open Access Journals (Sweden)

    Tomislav Novosel

    1998-12-01

    Full Text Available On the site of Maslenica bridge structural tectonic, geophysical and engineering geological investigations, geotechnical drilling and laboratory sample testings were performed. Maslenica anticline is characteristic for the investigated area. It is built from the limestone of Cretaceous age. The anticline has an asymmetrical form with the vergence of the axial plane towards the north. Reverse faults with recent activities are present. The recent activity was proved by the discovery of the broken stalactite with the displacement of 11 cm, whose age is 36000 years. On quite young stalactites (stalagmites in the cave on the west side, no displacements were noticed. For the next period of 500 years the maximal possible displacement of 2.0 cm is foreseen. Smaller caves with the dimensions of 1 m3, were formed on the intersections of the reverse faults and greater joints. The canyon Novsko ždrilo was formed in the fault shear zone with tectonic transport to the right. According to the range of fracture, three characteristic types of rock masses were separated by engineering geological investigations. According to »Geomechanical classification« (RMR the first type corresponds to II to III class, while the second type corresponds to IV class, and the third type corresponds to V class (mylonite. Because of the complexity of the terrain structure, original engineering geological bases of design have not enabled the direct application of the analysis of stress-strain behaviour. Because of that the simplified geotechnical models were done. They enabled the projecting of foundation in the rock mass and renewal of poor quality rock mass.

  17. Aneurysms: thoracic aortic aneurysms.

    Science.gov (United States)

    Chun, Kevin C; Lee, Eugene S

    2015-04-01

    Thoracic aortic aneurysms (TAAs) have many possible etiologies, including congenital heart defects (eg, bicuspid aortic valves, coarctation of the aorta), inherited connective tissue disorders (eg, Marfan, Ehlers-Danlos, Loeys-Dietz syndromes), and degenerative conditions (eg, medial necrosis, atherosclerosis of the aortic wall). Symptoms of rupture include a severe tearing pain in the chest, back, or neck, sometimes associated with cardiovascular collapse. Before rupture, TAAs may exert pressure on other thoracic structures, leading to a variety of symptoms. However, most TAAs are asymptomatic and are found incidentally during imaging for other conditions. Diagnosis is confirmed with computed tomography scan or echocardiography. Asymptomatic TAAs should be monitored with imaging at specified intervals and patients referred for repair if the TAAs are enlarging rapidly (greater than 0.5 cm in diameter over 6 months for heritable etiologies; greater than 0.5 cm over 1 year for degenerative etiologies) or reach a critical aortic diameter threshold for elective surgery (5.5 cm for TAAs due to degenerative etiologies, 5.0 cm when associated with inherited syndromes). Open surgery is used most often to treat asymptomatic TAAs in the ascending aorta and aortic arch. Asymptomatic TAAs in the descending aorta often are treated medically with aggressive blood pressure control, though recent data suggest that endovascular procedures may result in better long-term survival rates. PMID:25860136

  18. Experimental Model of Saccular Abdominal Aortic Aneurysm in Swines with Pericardium Sac

    Directory of Open Access Journals (Sweden)

    Maurício de Amorim Aquino

    2016-02-01

    Full Text Available Abstract Objective: To consider modifications in an experimental model of saccular aortic aneurysm, aiming at better reproducibility, to be used in the development of vascular prostheses. Methods: Experimental study in two phases, developed in the Center of Experimental Surgery and Bioterium (CCEB of the University of Health Sciences of Alagoas (UNCISAL, with 11 hybrid swine, female, mean weight of 20 ± 5 kg, according to modifications in the Perini technique was performed. In the first phase, the aneurysm was confectioned with bovine pericardial patch. In the second phase, fifteen days later, the patency of the aneurysms was confirmed by Doppler ultrasonography. The described variables were aortic and aneurysm sac patency, incidence of rupture, morbidity and mortality. The statistical analysis program used was STATA v.8. Results: All animals survived to the procedures. Surgical mean time was 73 minutes. Aneurysm rupture, proximal or distal aortic thrombosis, visceral or legs ischemia weren't observed. Parietal thrombus formation was observed in all of the aneurysms, two of which (18%; IC 95% = 3.98 - 48.84 were occluded and nine (82%; IC 95% = 51.15 - 96.01 were patent. Conclusion: In this series, the modifications carried out in the technique related to the surgical approach, race, anesthesia, and imaging exams reproduced the experimental model, reducing its costs, without hindering the analysis of the variables. The satisfactory patency ratio allows the method to be used in experimental models for the development of vascular prostheses.

  19. Estimating the Volatility of Cocoa Price Return with ARCH and GARCH Models

    Directory of Open Access Journals (Sweden)

    Lya Aklimawati

    2013-08-01

    Full Text Available Dynamics of market changing as a result of market liberalization have an impact on agricultural commodities price fluctuation. High volatility on cocoa price movement reflect its price and market risk. Because of price and market uncertainty, the market players face some difficulties to make a decision in determining business development. This research was conducted to 1 understand the characteristics of cocoa price movement in cocoa futures trading, and 2analyze cocoa price volatility using ARCH and GARCH type model. Research was carried out by direct observation on the pattern of cocoa price movement in the futures trading and volatility analysis based on secondary data. The data was derived from Intercontinental Exchange ( ICE Futures U.S. Reports. The analysis result showed that GARCH is the best model to predict the value of average cocoa price return volatility, because it meets criteria of three diagnostic checking, which are ARCH-LM test, residual autocorrelation test and residual normality test. Based on the ARCH-LM test, GARCH (1,1did not have heteroscedasticity, because p-value  2 (0.640139and F-statistic (0.640449 were greater than 0.05. Results of residual autocorrelation test indicated that residual value of GARCH (1,1 was random, because the statistic value of Ljung-Box (LBon the 36 th lag is smaller than the statistic value of  2. Whereas, residual normality test concluded the residual of GARCH (1,1 were normally distributed, because AR (29, MA (29, RESID (-1^2, and GARCH (-1 were significant at 5% significance level. Increasing volatility value indicate high potential risk. Price risk can be reduced by managing financial instrument in futures trading such as forward and futures contract, and hedging. The research result also give an insight to the market player for decision making and determining time of hedging. Key words: Volatility, price, cocoa, GARCH, risk, futures trading

  20. Experimental unsteady flow study in a patient-specific abdominal aortic aneurysm model

    Science.gov (United States)

    Stamatopoulos, Ch.; Mathioulakis, D. S.; Papaharilaou, Y.; Katsamouris, A.

    2011-06-01

    The velocity field in a patient-specific abdominal aneurysm model including the aorto-iliac bifurcation was measured by 2D PIV. Phase-averaged velocities obtained in 14 planes reveal details of the flow evolution during a cycle. The aneurysm expanding asymmetrically toward the anterior side of the aorta causes the generation of a vortex at its entrance, covering the entire aneurysm bulge progressively before flow peak. The fluid entering the aneurysm impinges on the left side of its distal end, following the axis of the upstream aorta segment, causing an increased flow rate in the left (compared to the right) common iliac artery. High shear stresses appear at the aneurysm inlet and outlet as well as along the posterior wall, varying proportionally to the flow rate. At the same regions, elevated flow disturbances are observed, being intensified at flow peak and during the deceleration phase. Low shear stresses are present in the recirculation region, being two orders of magnitude smaller than the previous ones. At flow peak and during the deceleration phase, a clockwise swirling motion (viewed from the inlet) is present in the aneurysm due to the out of plane curvature of the aorta.

  1. Aneurisma do ducto arterioso associado a interrupção do arco aórtico Aneurysm of the arterial duct associated to aortic arch interruption

    Directory of Open Access Journals (Sweden)

    Paulo Zielinsky

    1998-07-01

    Full Text Available É relatado um caso de aneurisma de ducto arterioso, com diagnóstico pré-natal, o que é muito raro, numa gestante com 33 semanas, onde o feto apresentou uma dilatação aneurismática do canal arterial, com calibre uniformemente aumentado, inserindo-se na aorta descendente, associado à interrupção do arco aórtico. A criança nasceu de parto cesáreo e manteve-se estável com o uso de prostaglandina até o 9º dia de vida, quando foi levada à cirurgia, tendo falecido durante o procedimento por falência biventricular. Este é o primeiro relato da associação desta anomalia com outra malformação cardiovascular intra-uterina, mostrando que este achado nem sempre é associado a uma evolução benigna.Aneurysm of the arterial duct is an infrequent finding, which is very rarely detected prenatally. A case of antenatal diagnosis in a pregnant patient (33 weeks is reported. The fetus presented an aneurysmatic dilation of the arterial duct with uniformly enlarged diameter, inserting into the descending aorta, which was interrupted. The neonate was born by cesarean section and was kept on postaglandins till the 9th day of life, when he was sent to surgery. During the surgical procedure, the baby died as a result of biventricular failure. This is the first report of prenatal association of aneurysm of the ducts anteriosus with other cardiovascular malformations and emphasizes that this finding does not always have a benign course.

  2. Effects of Hydroxyapatite on Bone Graft Resorption in an Experimental Model of Maxillary Alveolar Arch Defects

    Directory of Open Access Journals (Sweden)

    Ozgur Pilanci

    2013-06-01

    Full Text Available Most commonly used treatments use autologous bone grafts to address bony defects in patients with cleft palate. Major disadvantages of autogenous bone grafts include donor site morbidity and resorption. Suggestions to overcome such problems include biomaterials that can be used alone or in combination with bone. We examined the effect of hydroxyapatite cement on bone graft resorption in a rabbit maxillary alveolar defect model. We divided 16 young adult albino New Zealand rabbits into two groups. A defect 1 cm wide was created in each rabbit's maxillary arch. In Group 1, the removed bone was disrupted, and the pieces were replaced in the defect. In the other group, the pieces were replaced after mixing (1:1 with hydroxyapatite cement. Quantitative computed tomographic evaluation of these grafts was performed in axial and coronal planes for each rabbit at 2 and 12 weeks. In axial images at 12 weeks, the group without cement showed mean bone resorption of 15%. In the cement group, a mean volumetric increase of 68% was seen. No resorption occurred when bone grafts were mixed with hydroxyapatite cement. [Arch Clin Exp Surg 2013; 2(3.000: 170-175

  3. The analysis of volatility of gold coin price fluctuations in Iran using ARCH & VAR models

    Directory of Open Access Journals (Sweden)

    Younos Vakilolroaya

    2014-03-01

    Full Text Available The aim of this study is to investigate the changes in gold price and modeling of its return volatility and conditional variance model. The study gathers daily prices of gold coins as the dependent variable and the price of gold in world market, the price of oil in OPEC, exchange rate USD to IRR and index of Tehran Stock Exchange from March 2007 to July 2013 and using ARCH family models and VAR methods, the study analysis the data. The study first examines whether the data are stationary or not and then it reviews the household stability, Arch and Garch models. The proposed study investigates the causality among variables, selects different factors, which could be blamed of uncertainty in the coin return. The results indicate that the effect of sudden changes of standard deviation and after a 14-day period disappears and gold price goes back to its initial position. In addition, in this study we observe the so-called leverage effect in Iran’s Gold coin market, which means the good news leads to more volatility in futures market than bad news in an equal size. Finally, the result of analysis of variance implies that in the short-term, a large percentage change in uncertainty of the coin return is due to changes in the same factors and volatility of stock returns in the medium term, global gold output, oil price and exchange rate fluctuation to some extent will show the impact. In the long run, the effects of parameters are more evident.

  4. Blood flow in intracranial aneurysms treated with Pipeline embolization devices: computational simulation and verification with Doppler ultrasonography on phantom models

    Directory of Open Access Journals (Sweden)

    Anderson Chun On Tsang

    2015-04-01

    Full Text Available Purpose: The aim of this study was to validate a computational fluid dynamics (CFD simulation of flow-diverter treatment through Doppler ultrasonography measurements in patient-specific models of intracranial bifurcation and side-wall aneurysms. Methods: Computational and physical models of patient-specific bifurcation and sidewall aneurysms were constructed from computed tomography angiography with use of stereolithography, a three-dimensional printing technology. Flow dynamics parameters before and after flow-diverter treatment were measured with pulse-wave and color Doppler ultrasonography, and then compared with CFD simulations. Results: CFD simulations showed drastic flow reduction after flow-diverter treatment in both aneurysms. The mean volume flow rate decreased by 90% and 85% for the bifurcation aneurysm and the side-wall aneurysm, respectively. Velocity contour plots from computer simulations before and after flow diversion closely resembled the patterns obtained by color Doppler ultrasonography. Conclusion: The CFD estimation of flow reduction in aneurysms treated with a flow-diverting stent was verified by Doppler ultrasonography in patient-specific phantom models of bifurcation and side-wall aneurysms. The combination of CFD and ultrasonography may constitute a feasible and reliable technique in studying the treatment of intracranial aneurysms with flow-diverting stents.

  5. Image based hemodynamic modeling of cerebral aneurysms and the determination of the risk of rupture

    Science.gov (United States)

    Kroon, D. J.; Slump, C. H.; Sluzewski, M.; van Rooij, W. J. J.

    2006-03-01

    This paper is about the quantitative prediction of the long term outcome of the endovascular coiling treatment of a patient's cerebral aneurysm. It is generally believed that the local hemodynamic properties of the patient's cerebral arteries are strongly influencing the origin and growth of aneurysms. We describe our approach: modelling the flow in a 3D Rotational Angiography (3DRA) reconstruction of the aneurysms including supplying and draining blood vessels, in combination with simulations and experiments of artificial blood vessel phantom constructs and measurements. The goal is to obtain insight in the observed phenomena to support the diagnostic decision process in order to predict the outcome of the intervention with possible simulation of the flow alternation due to the pertinent intervention.

  6. Predictive Models with Patient Specific Material Properties for the Biomechanical Behavior of Ascending Thoracic Aneurysms.

    Science.gov (United States)

    Trabelsi, Olfa; Duprey, Ambroise; Favre, Jean-Pierre; Avril, Stéphane

    2016-01-01

    The aim of this study is to identify the patient-specific material properties of ascending thoracic aortic aneurysms (ATAA) using preoperative dynamic gated computed tomography (CT) scans. The identification is based on the simultaneous minimization of two cost functions, which define the difference between model predictions and gated CT measurements of the aneurysm volume at respectively systole and cardiac mid-cycle. The method is applied on five patients who underwent surgical repair of their ATAA at the University Hospital Center of St. Etienne. For these patients, the aneurysms were collected and tested mechanically using an in vitro bench. For the sake of validation, the mechanical properties found using the in vivo approach and the in vitro bench were compared. We eventually performed finite-element stress analyses based on each set of material properties. Rupture risk indexes were estimated and compared, showing promising results of the patient-specific identification method based on gated CT. PMID:26178871

  7. Proactive monitoring and adaptive management of social carrying capacity in Arches National Park: an application of computer simulation modeling.

    Science.gov (United States)

    Lawson, Steven R; Manning, Robert E; Valliere, William A; Wang, Benjamin

    2003-07-01

    Public visits to parks and protected areas continue to increase and may threaten the integrity of natural and cultural resources and the quality of the visitor experience. Scientists and managers have adopted the concept of carrying capacity to address the impacts of visitor use. In the context of outdoor recreation, the social component of carrying capacity refers to the level of visitor use that can be accommodated in parks and protected areas without diminishing the quality of the visitor experience to an unacceptable degree. This study expands and illustrates the use of computer simulation modeling as a tool for proactive monitoring and adaptive management of social carrying capacity at Arches National Park. A travel simulation model of daily visitor use throughout the Park's road and trail network and at selected attraction sites was developed, and simulations were conducted to estimate a daily social carrying capacity for Delicate Arch, an attraction site in Arches National Park, and for the Park as a whole. Further, a series of simulations were conducted to estimate the effect of a mandatory shuttle bus system on daily social carrying capacity of Delicate Arch to illustrate how computer simulation modeling can be used as a tool to facilitate adaptive management of social carrying capacity.

  8. Establishment of a chronic left ventricular aneurysm model in rabbit

    Institute of Scientific and Technical Information of China (English)

    Cang-Song XIAO; Chang-Qing GAO; Li-Bing LI; Yao WANG; Tao ZHAO; Wei-Hua YE; Chong-Lei REN; Zhi-Yong LIU; Yang WU

    2014-01-01

    Objectives To establish a cost-effective and reproducible procedure for induction of chronic left ventricular aneurysm (LVA) in rabbits. Methods Acute myocardial infarction (AMI) was induced in 35 rabbits via concomitant ligation of the left anterior descending (LAD) coronary artery and the circumflex (Cx) branch at the middle portion. Development of AMI was co n-firmed by ST segment elevation and akinesis of the occluded area. Echocardiography, pathological evaluation, and agar i n-tra-chamber casting were utilized to validate the formation of LVA four weeks after the surgery. Left ventricular end systolic pressure (LVESP) and diastolic pressure (LVEDP) were measured before, immediately after and four weeks after ligation. D i-mensions of the ventricular chamber, thickness of the interventricular septum (IVS) and the left ventricular posterior wall (LVPW) left ventricular end diastolic volume (LVEDV) and systolic volume (LVESV), and ejection fraction (EF) were recorded by echo-cardiography. Results Thirty one (88.6%) rabbits survived myocardial infarction and 26 of them developed aneurysm (83.9%). The mean area of aneurysm was 33.4% ± 2.4% of the left ventricle. LVEF markedly decreased after LVA formation, whereas LVEDV, LVESV and the thickness of IVS as well as the dimension of ventricular chamber from apex to mitral valve annulus significantly increased. LVESP immediately dropped after ligation and recovered to a small extent after LVA formation. LVEDP progressively increased after ligation till LVA formation. Areas in the left ventricle (LV) that underwent fibrosis included the apex, anterior wall and lateral wall but not IVS. Agar intra-chamber cast showed that the bulging of LV wall was prominent in the area of aneurysm. Conclusions Ligation of LAD and Cx at the middle portion could induce develo pment of LVA at a mean area ratio of 33.4%±2.4%which involves the apex, anterior wall and lateral wall of the LV.

  9. A new flow-diverter(the FloWise): In vivo evaluation in an elastase-induced rabbit aneurysm model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byung Moon; Kim, Dong Joon; Kim, Dong Ik [Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2016-02-15

    We aimed to evaluate the efficacy and safety of a newly developed, partially retrievable flow-diverter (the FloWise) in an elastase-induced rabbit aneurysm model. We developed a partially retrievable flow diverter composed of 48 strands of Nitinol and platinum wire. The FloWise is compatible with any microcatheter of 0.027-inch inner diameter, and is retrievable up to 70% deployment. The efficacy and safety of the FloWise were evaluated in the elastase-induced rabbit aneurysm model. The rate of technical success (full coverage of aneurysm neck) and assessment of aneurysm occlusion and stent patency was conducted by angiograms and histologic examinations at the 1-month, 3-month, and 6-month follow-up. The patency of small arterial branches (intercostal or lumbar arteries) covered by the FloWise were also assessed in the 5 subjects. We attempted FloWise insertion in a total of 32 aneurysm models. FloWise placement was successful in 31 subjects (96.9%). Two stents (6.2%) were occluded at the 3-month follow-up, but there was no evidence of in-stent stenosis in other subjects. All stented aneurysms showed progressive occlusion: grade I (complete aneurysm occlusion) in 44.4% and grade II (aneurysm occlusion > 90%) in 55.6% at 1 month; grade I in 90% and II in 10% at 3 months; and grade I in 90% and II in 10% at 6 months. All small arterial branches covered by the FloWise remained patent. A newly developed, partially retrievable flow-diverter seems to be a safe and effective tool of aneurysm occlusion, as evaluated in the rabbit aneurysm model.

  10. Glossary to ARCH (GARCH)

    DEFF Research Database (Denmark)

    Bollerslev, Tim

    The literature on modeling and forecasting time-varying volatility is ripe with acronyms and abbreviations used to describe the many different parametric models that have been put forth since the original linear ARCH model introduced in the seminal Nobel Prize winning paper by Engle (1982......).  The present paper provides an easy-to-use encyclopedic reference guide to this long list of ARCH acronyms.  In addition to the acronyms associated with specific parametric models, I have also included descriptions of various abbreviations associated with more general statistical procedures and ideas...

  11. 主动脉夹层动脉瘤的杂交外科治疗%Hybrid treatment of aortic dissecting aneurysm with entrance in aortic arch

    Institute of Scientific and Technical Information of China (English)

    邬晓臣; 张近宝; 欧阳辉; 丁盛; 岳琴; 周凯; 辛梅; 张宇兵

    2011-01-01

    Objective To observe hybrid surgical techniques and therapeutic effects of vascular prosthesis bridging and endovascular stent graft exclusion in aortic dissecting aneurysm. Methods Thirty-eight patients with aortic dissection (AD) were treated by hybrid surgical treatment, including 19 cases of left-right common carotid arteries bypass graft, 12 cases of common carotid artery-ascending aorta bypass graft, 4 cases of common carotid artery-subclavian artery bypass graft and 3 cases of abdominal aorta-bilateral renal artery bypass graft. Clinical and computed tomography outcome were analyzed during follow-up. Results Successful operation was performed in all cases, with tiny incision and complete disappearance of the false lumen or remarkable decrease of the endoleak on the angiograms. No case of stent migration, 1 case of internal hemorrhage due to trauma, 3 cases of new breaks were observed and cured by endovascular graft exclusion. There were 2 cases of death. Conclusion Hybrid surgical procedure, with fewer complications and quicker recovery, has great therapeutic effect in treatment of aortic dissection.%目的 探讨主动脉弓部破口的主动脉夹层动脉瘤的杂交外科治疗经验.方法 分析应用杂交外科手术治疗38例主动脉夹层患者,按照架桥方法及术式分为:颈总动脉间架桥加腔内隔绝术19例,颈总动脉-升主动脉架桥加腔内隔绝术12例,颈总动脉-锁骨下动脉架桥加腔内隔绝术4例,腹主动脉-双侧肾动脉架桥加腔内隔绝术3例.结果 所有患者夹层破口均被闭合,恢复真腔血流,住院死亡2例(成功率5.2%),术后复查均未发生支架移位,1例原夹层破口处出现内漏,3例出现新破口,再次分别行腔内支架隔绝治愈.结论 主动脉夹层动脉瘤可通过外科手术结合腔内隔绝介入的综合外科治疗方案可以取得良好的效果,降低手术风险,提高手术治愈率.

  12. Induction of continuous expanding infrarenal aortic aneurysms in a large porcine animal model

    Directory of Open Access Journals (Sweden)

    Brian O. Kloster

    2015-03-01

    Conclusion: In pigs it's possible to induce continuous expanding AAA's based upon proteolytic degradation and pathological flow, resembling the real life dynamics of human aneurysms. Because the lumbars are preserved, it's also a potential model for further studies of novel endovascular devices and their complications.

  13. A two-system, single-analysis, fluid-structure interaction technique for modelling abdominal aortic aneurysms.

    Science.gov (United States)

    Kelly, S C; O'Rourke, M J

    2010-01-01

    This work reports on the implementation and validation of a two-system, single-analysis, fluid-structure interaction (FSI) technique that uses the finite volume (FV) method for performing simulations on abdominal aortic aneurysm (AAA) geometries. This FSI technique, which was implemented in OpenFOAM, included fluid and solid mesh motion and incorporated a non-linear material model to represent AAA tissue. Fully implicit coupling was implemented, ensuring that both the fluid and solid domains reached convergence within each time step. The fluid and solid parts of the FSI code were validated independently through comparison with experimental data, before performing a complete FSI simulation on an idealized AAA geometry. Results from the FSI simulation showed that a vortex formed at the proximal end of the aneurysm during systolic acceleration, and moved towards the distal end of the aneurysm during diastole. Wall shear stress (WSS) values were found to peak at both the proximal and distal ends of the aneurysm and remain low along the centre of the aneurysm. The maximum von Mises stress in the aneurysm wall was found to be 408kPa, and this occurred at the proximal end of the aneurysm, while the maximum displacement of 2.31 mm occurred in the centre of the aneurysm. These results were found to be consistent with results from other FSI studies in the literature. PMID:20923114

  14. Development of a static bioactive stent prototype and dynamic aneurysm-on-a-chip(TM) model for the treatment of aneurysms

    Science.gov (United States)

    Reece, Lisa M.

    Aneurysms are pockets of blood that collect outside blood vessel walls forming dilatations and leaving arterial walls very prone to rupture. Current treatments include: (1) clipping, and (2) coil embolization, including stent-assisted coiling. While these procedures can be effective, it would be advantageous to design a biologically active stent, modified with magnetic stent coatings, allowing cells to be manipulated to heal the arterial lining. Further, velocity, pressure, and wall shear stresses aid in the disease development of aneurysmal growth, but the shear force mechanisms effecting wound closure is elusive. Due to these factors, there is a definite need to cultivate a new stent device that will aid in healing an aneurysm in situ. To this end, a static bioactive stent device was synthesized. Additionally, to study aneurysm pathogenesis, a lab-on-a-chip device (a dynamic stent device) is the key to discovering the underlying mechanisms of these lesions. A first step to the reality of a true bioactive stent involves the study of cells that can be tested against the biomaterials that constitute the stent itself. The second step is to test particles/cells in a microfluidic environment. Therefore, biocompatability data was collected against PDMS, bacterial nanocellulose (BNC), and magnetic bacterial nanocellulose (MBNC). Preliminary static bioactive stents were synthesized whereby BNC was grown to cover standard nitinol stents. In an offshoot of the original research, a two-dimensional microfluidic model, the Aneurysm-on-a-ChipTM (AOC), was the logical answer to study particle flow within an aneurysm "sac" - this was the dynamic bioactive stent device. The AOC apparatus can track particles/cells when it is coupled to a particle image velocimetry software (PIV) package. The AOC fluid flow was visualized using standard microscopy techniques with commercial microparticles/cells. Movies were taken during fluid flow experiments and PIV was utilized to monitor.

  15. Fluid structure interaction simulation in three-layered aortic aneurysm model under pulsatile flow: comparison of wrapping and stenting.

    Science.gov (United States)

    Gao, Feng; Ueda, Hiroshi; Gang, Li; Okada, Hiroshi

    2013-04-26

    One treatment method for aortic aneurysm is the invasive insertion of a stent into the aneurysm. Another method is wrapping the aneurysm using newly developed expanded polytetrafluoroethylene (PTFE) material. A virtual stented aneurysm model and a wrapped aneurysm model were created to study the flow and wall dynamics by means of fluid-structure interaction analyses. The flow velocity and pressure distribution as well as the deformation and wall stress were investigated. Stenting significantly changed the blood flow pattern and the vortexes in the aneurysm. Wrapping increased the thickness of the aneurysm wall and increased the strength of the vessel wall. The maximum von Mises stress in the stented model was found to be 220,494 Pa and 228,218 Pa at the time of peak flow and peak pressure, respectively. This was reduced by 37.8% and 36.7% to 137,200 and 144,354 Pa, respectively, in the wrapped model. Our results provide information that may improve the understanding of the biomechanics of stenting and wrapping.

  16. Flow dynamics in anatomical models of abdominal aortic aneurysms: computational analysis of pulsatile flow.

    Science.gov (United States)

    Finol, Ender A; Amon, Cristina H

    2003-01-01

    Blood flow in human arteries is dominated by time-dependent transport phenomena. In particular, in the abdominal segment of the aorta under a patient's average resting conditions, blood exhibits laminar flow patterns that are influenced by secondary flows induced by adjacent branches and in irregular vessel geometries. The flow dynamics becomes more complex when there is a pathological condition that causes changes in the normal structural composition of the vessel wall, for example, in the presence of an aneurysm. An aneurysm is an irreversible dilation of a blood vessel accompanied by weakening of the vessel wall. This work examines the importance of hemodynamics in the characterization of pulsatile blood flow patterns in individual Abdominal Aortic Aneurysm (AAA) models. These patient-specific computational models have been developed for the numerical simulation of the momentum transport equations utilizing the Finite Element Method (FEM) for the spatial and temporal discretization. We characterize pulsatile flow dynamics in AAAs for average resting conditions by means of identifying regions of disturbed flow and quantifying the disturbance by evaluating wall pressure and wall shear stresses at the aneurysm wall. PMID:14515766

  17. Deformation Monitoring of Geomechanical Model Test and Its Application in Overall Stability Analysis of a High Arch Dam

    Directory of Open Access Journals (Sweden)

    Baoquan Yang

    2015-01-01

    Full Text Available Geomechanical model testing is an important method for studying the overall stability of high arch dams. The main task of a geomechanical model test is deformation monitoring. Currently, many types of deformation instruments are used for deformation monitoring of dam models, which provide valuable information on the deformation characteristics of the prototype dams. However, further investigation is required for assessing the overall stability of high arch dams through analyzing deformation monitoring data. First, a relationship for assessing the stability of dams is established based on the comprehensive model test method. Second, a stability evaluation system is presented based on the deformation monitoring data, together with the relationships between the deformation and overloading coefficient. Finally, the comprehensive model test method is applied to study the overall stability of the Jinping-I high arch dam. A three-dimensional destructive test of the geomechanical model dam is conducted under reinforced foundation conditions. The deformation characteristics and failure mechanisms of the dam abutments and foundation were investigated. The test results indicate that the stability safety factors of the dam abutments and foundation range from 5.2 to 6.0. These research results provide an important scientific insight into the design, construction, and operation stages of this project.

  18. Measurement with microscopic MRI and simulation of flow in different aneurysm models

    Energy Technology Data Exchange (ETDEWEB)

    Edelhoff, Daniel, E-mail: daniel.edelhoff@tu-dortmund.de; Frank, Frauke; Heil, Marvin; Suter, Dieter [Experimental Physics III, TU Dortmund University, Otto-Hahn-Street 4, Dortmund 44227 (Germany); Walczak, Lars; Weichert, Frank [Computer Science VII, TU Dortmund University, Otto-Hahn-Street 16, Dortmund 44227 (Germany); Schmitz, Inge [Institute for Pathology, Ruhr Universität Bochum, Bürkle-de-la-Camp-Platz 1, Bochum 44789 (Germany)

    2015-10-15

    Purpose: The impact and the development of aneurysms depend to a significant degree on the exchange of liquid between the regular vessel and the pathological extension. A better understanding of this process will lead to improved prediction capabilities. The aim of the current study was to investigate fluid-exchange in aneurysm models of different complexities by combining microscopic magnetic resonance measurements with numerical simulations. In order to evaluate the accuracy and applicability of these methods, the fluid-exchange process between the unaltered vessel lumen and the aneurysm phantoms was analyzed quantitatively using high spatial resolution. Methods: Magnetic resonance flow imaging was used to visualize fluid-exchange in two different models produced with a 3D printer. One model of an aneurysm was based on histological findings. The flow distribution in the different models was measured on a microscopic scale using time of flight magnetic resonance imaging. The whole experiment was simulated using fast graphics processing unit-based numerical simulations. The obtained simulation results were compared qualitatively and quantitatively with the magnetic resonance imaging measurements, taking into account flow and spin–lattice relaxation. Results: The results of both presented methods compared well for the used aneurysm models and the chosen flow distributions. The results from the fluid-exchange analysis showed comparable characteristics concerning measurement and simulation. Similar symmetry behavior was observed. Based on these results, the amount of fluid-exchange was calculated. Depending on the geometry of the models, 7% to 45% of the liquid was exchanged per second. Conclusions: The result of the numerical simulations coincides well with the experimentally determined velocity field. The rate of fluid-exchange between vessel and aneurysm was well-predicted. Hence, the results obtained by simulation could be validated by the experiment. The

  19. [Rapid 3-Dimensional Models of Cerebral Aneurysm for Emergency Surgical Clipping].

    Science.gov (United States)

    Konno, Takehiko; Mashiko, Toshihiro; Oguma, Hirofumi; Kaneko, Naoki; Otani, Keisuke; Watanabe, Eiju

    2016-08-01

    We developed a method for manufacturing solid models of cerebral aneurysms, with a shorter printing time than that involved in conventional methods, using a compact 3D printer with acrylonitrile-butadiene-styrene(ABS)resin. We further investigated the application and utility of this printing system in emergency clipping surgery. A total of 16 patients diagnosed with acute subarachnoid hemorrhage resulting from cerebral aneurysm rupture were enrolled in the present study. Emergency clipping was performed on the day of hospitalization. Digital Imaging and Communication in Medicine(DICOM)data obtained from computed tomography angiography(CTA)scans were edited and converted to stereolithography(STL)file formats, followed by the production of 3D models of the cerebral aneurysm by using the 3D printer. The mean time from hospitalization to the commencement of surgery was 242 min, whereas the mean time required for manufacturing the 3D model was 67 min. The average cost of each 3D model was 194 Japanese Yen. The time required for manufacturing the 3D models shortened to approximately 1 hour with increasing experience of producing 3D models. Favorable impressions for the use of the 3D models in clipping were reported by almost all neurosurgeons included in this study. Although 3D printing is often considered to involve huge costs and long manufacturing time, the method used in the present study requires shorter time and lower costs than conventional methods for manufacturing 3D cerebral aneurysm models, thus making it suitable for use in emergency clipping. PMID:27506842

  20. CFD Modelling of Abdominal Aortic Aneurysm on Hemodynamic Loads Using a Realistic Geometry with CT

    OpenAIRE

    Loong, T. H.; Maurizio Bordone; Uei Pua; Sriram Narayanan; Eduardo Soudah; E. Y. K. Ng

    2013-01-01

    The objective of this study is to find a correlation between the abdominal aortic aneurysm (AAA) geometric parameters, wall stress shear (WSS), abdominal flow patterns, intraluminal thrombus (ILT), and AAA arterial wall rupture using computational fluid dynamics (CFD). Real AAA 3D models were created by three-dimensional (3D) reconstruction of in vivo acquired computed tomography (CT) images from 5 patients. Based on 3D AAA models, high quality volume meshes were created using an optimal tetr...

  1. Implantation of 3D-Printed Patient-Specific Aneurysm Models into Cadaveric Specimens: A New Training Paradigm to Allow for Improvements in Cerebrovascular Surgery and Research

    Directory of Open Access Journals (Sweden)

    Arnau Benet

    2015-01-01

    Full Text Available Aim. To evaluate the feasibility of implanting 3D-printed brain aneurysm model in human cadavers and to assess their utility in neurosurgical research, complex case management/planning, and operative training. Methods. Two 3D-printed aneurysm models, basilar apex and middle cerebral artery, were generated and implanted in four cadaveric specimens. The aneurysms were implanted at the same anatomical region as the modeled patient. Pterional and orbitozygomatic approaches were done on each specimen. The aneurysm implant, manipulation capabilities, and surgical clipping were evaluated. Results. The 3D aneurysm models were successfully implanted to the cadaveric specimens’ arterial circulation in all cases. The features of the neck in terms of flexibility and its relationship with other arterial branches allowed for the practice of surgical maneuvering characteristic to aneurysm clipping. Furthermore, the relationship of the aneurysm dome with the surrounding structures allowed for better understanding of the aneurysmal local mass effect. Noticeably, all of these observations were done in a realistic environment provided by our customized embalming model for neurosurgical simulation. Conclusion. 3D aneurysms models implanted in cadaveric specimens may represent an untapped training method for replicating clip technique; for practicing certain approaches to aneurysms specific to a particular patient; and for improving neurosurgical research.

  2. Implantation of 3D-Printed Patient-Specific Aneurysm Models into Cadaveric Specimens: A New Training Paradigm to Allow for Improvements in Cerebrovascular Surgery and Research

    Science.gov (United States)

    Benet, Arnau; Plata-Bello, Julio; Abla, Adib A.; Acevedo-Bolton, Gabriel; Saloner, David; Lawton, Michael T.

    2015-01-01

    Aim. To evaluate the feasibility of implanting 3D-printed brain aneurysm model in human cadavers and to assess their utility in neurosurgical research, complex case management/planning, and operative training. Methods. Two 3D-printed aneurysm models, basilar apex and middle cerebral artery, were generated and implanted in four cadaveric specimens. The aneurysms were implanted at the same anatomical region as the modeled patient. Pterional and orbitozygomatic approaches were done on each specimen. The aneurysm implant, manipulation capabilities, and surgical clipping were evaluated. Results. The 3D aneurysm models were successfully implanted to the cadaveric specimens' arterial circulation in all cases. The features of the neck in terms of flexibility and its relationship with other arterial branches allowed for the practice of surgical maneuvering characteristic to aneurysm clipping. Furthermore, the relationship of the aneurysm dome with the surrounding structures allowed for better understanding of the aneurysmal local mass effect. Noticeably, all of these observations were done in a realistic environment provided by our customized embalming model for neurosurgical simulation. Conclusion. 3D aneurysms models implanted in cadaveric specimens may represent an untapped training method for replicating clip technique; for practicing certain approaches to aneurysms specific to a particular patient; and for improving neurosurgical research. PMID:26539542

  3. Semi- and Nonparametric ARCH Processes

    Directory of Open Access Journals (Sweden)

    Oliver B. Linton

    2011-01-01

    Full Text Available ARCH/GARCH modelling has been successfully applied in empirical finance for many years. This paper surveys the semiparametric and nonparametric methods in univariate and multivariate ARCH/GARCH models. First, we introduce some specific semiparametric models and investigate the semiparametric and nonparametrics estimation techniques applied to: the error density, the functional form of the volatility function, the relationship between mean and variance, long memory processes, locally stationary processes, continuous time processes and multivariate models. The second part of the paper is about the general properties of such processes, including stationary conditions, ergodic conditions and mixing conditions. The last part is on the estimation methods in ARCH/GARCH processes.

  4. Development of an abdominal aortic aneurysm model for stent-graft insertion

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Hyung; Lee, Jong Heon; Shin, Dong Ik; Sung, Kyu Bo; Ko, Gi Young; Lim, Jin Oh [College of Medicine, Univ. of Ulsan, Seoul (Korea, Republic of); Kim, Si Hoon [S and G Biotech Research Institute, Seoul (Korea, Republic of)

    2002-03-01

    To determine the efficacy of an abdominal aortic aneurysm model for stent-graft placement. The model consists of two parts, the heart and the vascular system. A peristaltic pump and a solenoid valve were used to simulate a pulsatile flow from the heart. A ball-shaped piece of clay was placed inside a square box and liquid silicone was poured. After the silicone was formed, the clay was removed and a silicone tube was used to connect the heart model and the aneurysm model. The silicone tube was also used to simulate the iliac arteries and one end of the artery was clampled and the other one was extended to water bath. Water at 37 .deg. C was circulated through the model, and the pressure at the thoracic aorta, aneurysm and iliac artery was measured with the outlet valve opening at 25, 50, and 100% before and after stent-graft placement. The liquid pressure measurements were 253/252, 271/162 and 264/166 mmHg at the thoracic aorta, aneurysm and iliac artery, respectively, when the outlet was 100% open. They were 173/121, 145/99, 145/106 mmHg when the outlet was 50% open, and 35/28, 61/44, 24/22 mmHg when it was 25% open. After placement of the stent-graft, the pressure measurements were 170/128, and 167/128 mmHg, respectively. Since it was easy to produce, the model was useful for in-vitro stent-graft testing, and a wide range of pressure could be applied.

  5. Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect

    Directory of Open Access Journals (Sweden)

    H. Mirzabozorg

    2014-01-01

    Full Text Available The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams.

  6. Aortic Aneurysm

    Science.gov (United States)

    ... Most aneurysms are in the aorta, the main artery that runs from the heart through the chest and abdomen. There are two types of aortic aneurysm: Thoracic aortic aneurysms (TAA) - these occur in the part of the aorta running through the chest Abdominal aortic aneurysms (AAA) - these occur in the part ...

  7. Management of A Patient with Kommerrell's Aneurysm Causing Tracheal and Esophageal Compression

    OpenAIRE

    Ranjith B Karthekeyan; Syama Sundar; Suresh Rao; Mahesh Vakamudi

    2009-01-01

    Summary Tracheal and esophageal compression is a well-recognized complication of aneurysms of the aortic arch. Most of the patients present with dysphagia and/or respiratory insufficiency. In the adult population a right-sided aortic arch is often asymptomatic unless aneurysmal disease develops. This usually occurs at the level of the take-off of an aberrant left subclavian artery and is known as a Kommerell's aneurysm. In spite of its rarity, this condition is clinically relevant because of ...

  8. Induction of continuous expanding infrarenal aortic aneurysms in a large porcine animal model

    DEFF Research Database (Denmark)

    Kloster, Brian Ozeraitis; Lund, Lars; Lindholt, Jes S.

    2015-01-01

    BACKGROUND: A large animal model with a continuous expanding infrarenal aortic aneurysm gives access to a more realistic AAA model with anatomy and physiology similar to humans, and thus allows for new experimental research in the natural history and treatment options of the disease. METHODS: 10...... ultrasound, hereafter the pigs were euthanized for inspection and AAA wall sampling for histological analysis. RESULTS: In group A, all pigs developed continuous expanding AAA's with a mean increase in AP-diameter to 16.26 ± 0.93 mm equivalent to a 57% increase. In group B the AP-diameters increased to 11...... in group A. The most frequent complication was a neurological deficit in the lower limbs. CONCLUSION: In pigs it's possible to induce continuous expanding AAA's based upon proteolytic degradation and pathological flow, resembling the real life dynamics of human aneurysms. Because the lumbars are preserved...

  9. Endoleak Assessment Using Computational Fluid Dynamics and Image Processing Methods in Stented Abdominal Aortic Aneurysm Models

    Science.gov (United States)

    Lu, Yueh-Hsun; Mani, Karthick; Panigrahi, Bivas; Hsu, Wen-Tang

    2016-01-01

    Endovascular aortic aneurysm repair (EVAR) is a predominant surgical procedure to reduce the risk of aneurysm rupture in abdominal aortic aneurysm (AAA) patients. Endoleak formation, which eventually requires additional surgical reoperation, is a major EVAR complication. Understanding the etiology and evolution of endoleak from the hemodynamic perspective is crucial to advancing the current posttreatments for AAA patients who underwent EVAR. Therefore, a comprehensive flow assessment was performed to investigate the relationship between endoleak and its surrounding pathological flow fields through computational fluid dynamics and image processing. Six patient-specific models were reconstructed, and the associated hemodynamics in these models was quantified three-dimensionally to calculate wall stress. To provide a high degree of clinical relevance, the mechanical stress distribution calculated from the models was compared with the endoleak positions identified from the computed tomography images of patients through a series of imaging processing methods. An endoleak possibly forms in a location with high local wall stress. An improved stent graft (SG) structure is conceived accordingly by increasing the mechanical strength of the SG at peak wall stress locations. The presented analytical paradigm, as well as numerical analysis using patient-specific models, may be extended to other common human cardiovascular surgeries.

  10. Endoleak Assessment Using Computational Fluid Dynamics and Image Processing Methods in Stented Abdominal Aortic Aneurysm Models

    Directory of Open Access Journals (Sweden)

    Yueh-Hsun Lu

    2016-01-01

    Full Text Available Endovascular aortic aneurysm repair (EVAR is a predominant surgical procedure to reduce the risk of aneurysm rupture in abdominal aortic aneurysm (AAA patients. Endoleak formation, which eventually requires additional surgical reoperation, is a major EVAR complication. Understanding the etiology and evolution of endoleak from the hemodynamic perspective is crucial to advancing the current posttreatments for AAA patients who underwent EVAR. Therefore, a comprehensive flow assessment was performed to investigate the relationship between endoleak and its surrounding pathological flow fields through computational fluid dynamics and image processing. Six patient-specific models were reconstructed, and the associated hemodynamics in these models was quantified three-dimensionally to calculate wall stress. To provide a high degree of clinical relevance, the mechanical stress distribution calculated from the models was compared with the endoleak positions identified from the computed tomography images of patients through a series of imaging processing methods. An endoleak possibly forms in a location with high local wall stress. An improved stent graft (SG structure is conceived accordingly by increasing the mechanical strength of the SG at peak wall stress locations. The presented analytical paradigm, as well as numerical analysis using patient-specific models, may be extended to other common human cardiovascular surgeries.

  11. Mining data from CFD simulation for aneurysm and carotid bifurcation models.

    Science.gov (United States)

    Miloš, Radović; Dejan, Petrović; Nenad, Filipović

    2011-01-01

    Arterial geometry variability is present both within and across individuals. To analyze the influence of geometric parameters, blood density, dynamic viscosity and blood velocity on wall shear stress (WSS) distribution in the human carotid artery bifurcation and aneurysm, the computer simulations were run to generate the data pertaining to this phenomenon. In our work we evaluate two prediction models for modeling these relationships: neural network model and k-nearest neighbor model. The results revealed that both models have high prediction ability for this prediction task. The achieved results represent progress in assessment of stroke risk for a given patient data in real time. PMID:22256273

  12. A microfabricated microfluidic bioMEMS device to model human brain aneurisms: the aneurysm-on-a-chip

    Science.gov (United States)

    Reece, Lisa M.; Khor, Jian Wei; Thakur, Raviraj; Amin, Ahmed; Wereley, Steven T.; Leary, James F.

    2015-03-01

    Aneurysms are pockets of blood that collect outside blood vessel walls forming dilatations and leaving arterial walls very prone to rupture. There is little information concerning the causes of intracranial aneurysm formation, growth, and rupture. Current treatments include: (1) clipping, and (2) coil embolization, including stent-assisted coiling. Further, the evolution of any aneurysm is assumed to be caused by the remodeling of the affected blood vessel's material constituents (tunica intima, tunica media, or tunica adventitia). Velocity, pressure, and wall shear stresses aid in the disease development of aneurysmal growth, while the shear force mechanisms effecting wound closure are elusive. To study aneurysm pathogenesis, a lab-on-a-chip device is the key to discovering the underlying mechanisms of these lesions. A two-dimensional microfluidic model, the Aneurysm-on-a-Chip™ (AOC), was the logical answer to study particle flow within an aneurysm "sac". The AOC apparatus can track particles/cells when it is coupled to particle image velocimetry software (PIV) package. The AOC fluid flow was visualized using standard microscopy techniques with commercial microparticles and human aortic smooth muscle cells (HASMC). Images were taken during fluid flow experiments and PIV was utilized to monitor the flow of particles within the "sac" region, as well as particles entering and exiting the device. Quiver plots were generated from fluid flow experiments using standard 7 μm latex particles and fixed HASMC in PBS. PIV analysis shows that the particles flowed nicely from input to output. Wall shear stress provided evidence that there was some back flow at the edges of the "sac" - an indicator of aneurysm development in human patients.

  13. Multilocular True Ulnar Artery Aneurysm in a Pediatric Patient

    OpenAIRE

    Stalder, Mark W.; Sanders, Christopher; Lago, Mary; Hilaire, Hugo St.

    2016-01-01

    Summary: Ulnar artery aneurysms are an exceedingly rare entity in the pediatric population and have no consistent etiologic mechanism. We present the case of a 15-year-old male with a multilocular ulnar artery aneurysm in the setting of no antecedent history of trauma, no identifiable connective tissue disorders, and no other apparent etiological factors. Furthermore, the patient’s arterial palmar arch system was absent. The aneurysm was resected, and arterial reconstruction was successfully ...

  14. A new experimental carotid siphon aneurysm model in canine based on the MR angiography and rapid prototyping technology

    International Nuclear Information System (INIS)

    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 intracranial carotid artery. Then 6 tubes were made in the 3D 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 geometry 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 stenting. Two vascular 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 the 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. (authors)

  15. Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect

    OpenAIRE

    Mirzabozorg, H.; Hariri-Ardebili, M. A.; Shirkhan, M.; S.M. Seyed-Kolbadi

    2014-01-01

    The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastic...

  16. In vitro and in vivo evaluation of a shape memory polymer foam-over-wire embolization device delivered in saccular aneurysm models.

    Science.gov (United States)

    Boyle, Anthony J; Landsman, Todd L; Wierzbicki, Mark A; Nash, Landon D; Hwang, Wonjun; Miller, Matthew W; Tuzun, Egemen; Hasan, Sayyeda M; Maitland, Duncan J

    2016-10-01

    Current endovascular therapies for intracranial saccular aneurysms result in high recurrence rates due to poor tissue healing, coil compaction, and aneurysm growth. We propose treatment of saccular aneurysms using shape memory polymer (SMP) foam to improve clinical outcomes. SMP foam-over-wire (FOW) embolization devices were delivered to in vitro and in vivo porcine saccular aneurysm models to evaluate device efficacy, aneurysm occlusion, and acute clotting. FOW devices demonstrated effective delivery and stable implantation in vitro. In vivo porcine aneurysms were successfully occluded using FOW devices with theoretical volume occlusion values greater than 72% and rapid, stable thrombus formation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1407-1415, 2016.

  17. Time analysis of aneurysm wall shear stress for both Newtonian and Casson flows from image-based CFD models

    Science.gov (United States)

    Castro, Marcelo A.; Ahumada Olivares, María. C.; Putman, Christopher M.; Cebral, Juan R.

    2014-03-01

    The optimal management of unruptured aneurysms is controversial, and current decision making is mainly based on aneurysm size and location. Incidentally detected unruptured aneurysms less than 5mm in diameter should be treated conservatively. However, small unruptured aneurysms also bleed. Risk factors based on the hemodynamic forces exerted over the arterial wall have been investigated using image-based computational fluid dynamic (CFD) methodologies during the last decade. Accurate estimation of wall shear stress (WSS) is required to properly study associations between flow features and aneurysm processes. Previous works showed that Newtonian and non-Newtonian (Casson) models produce similar WSS distributions and characterization, with no significant differences. Other authors showed that the WSS distribution computed from time-averaged velocity fields is significantly higher for the Newtonian model where WSS is low. In this work we reconstructed ten patient-specific CFD models from angiography images to investigate the time evolution of WSS at selected locations such as aneurysm blebs (low WSS), and the parent artery close to the aneurysm neck (high WSS). When averaging all cases it is seen that the estimation of the time-averaged WSS, the peak WSS and the minimum WSS value before the systolic peak were all higher when the Casson rheology was considered. However, none of them showed statistically significant differences. At the afferent artery Casson rheology systematically predicted higher WSS values. On the other hand, at the selected blebs either Newtonian or Casson WSS estimations are higher in some phases of the cardiac cycle. Those observations differ among individual cases.

  18. Brain Aneurysm

    Science.gov (United States)

    A brain aneurysm is an abnormal bulge or "ballooning" in the wall of an artery in the brain. They are sometimes called berry aneurysms because they ... often the size of a small berry. Most brain aneurysms produce no symptoms until they become large, ...

  19. The Murine Angiotensin II-Induced Abdominal Aortic Aneurysm Model: Rupture Risk and Inflammatory Progression Patterns

    OpenAIRE

    TimothySt. Amand

    2010-01-01

    An abdominal aortic aneurysm (AAA) is an enlargement of the greatest artery in the body defined as an increase in diameter of 1.5-fold. AAAs are common in the elderly population and thousands die each year from their complications. The most commonly used mouse model to study the pathogenesis of AAA is the angiotensin II (Ang II) infusion method delivered via osmotic mini-pump for 28 days. Here, we studied the site-specificity and onset of aortic rupture, characterized three-dimensional (3D) i...

  20. Ambient Vibration Tests of an Arch Dam with Different Reservoir Water Levels: Experimental Results and Comparison with Finite Element Modelling

    Directory of Open Access Journals (Sweden)

    Sergio Vincenzo Calcina

    2014-01-01

    Full Text Available This paper deals with the ambient vibration tests performed in an arch dam in two different working conditions in order to assess the effect produced by two different reservoir water levels on the structural vibration properties. The study consists of an experimental part and a numerical part. The experimental tests were carried out in two different periods of the year, at the beginning of autumn (October 2012 and at the end of winter (March 2013, respectively. The measurements were performed using a fast technique based on asynchronous records of microtremor time-series. In-contact single-station measurements were done by means of one single high resolution triaxial tromometer and two low-frequency seismometers, placed in different points of the structure. The Standard Spectral Ratio method has been used to evaluate the natural frequencies of vibration of the structure. A 3D finite element model of the arch dam-reservoir-foundation system has been developed to verify analytically determined vibration properties, such as natural frequencies and mode shapes, and their changes linked to water level with the experimental results.

  1. Embryonic tongue morphogenesis in an organ culture model of mouse mandibular arches: blocking Sonic hedgehog signaling leads to microglossia.

    Science.gov (United States)

    Torii, Daisuke; Soeno, Yuuichi; Fujita, Kazuya; Sato, Kaori; Aoba, Takaaki; Taya, Yuji

    2016-01-01

    Mouse tongue development is initiated with the formation of lateral lingual swellings just before fusion between the mediodorsal surfaces of the mandibular arches at around embryonic day 11.0. Here, we investigated the role of Sonic hedgehog (Shh) signaling in embryonic mouse tongue morphogenesis. For this, we used an organ culture model of the mandibular arches from mouse embryos at embryonic day 10.5. When the Shh signaling inhibitor jervine was added to the culture medium for 24-96 h, the formation of lateral lingual swellings and subsequent epithelial invagination into the mesenchyme were impaired markedly, leading to a hypoplastic tongue with an incomplete oral sulcus. Notably, jervine treatment reduced the proliferation of non-myogenic mesenchymal cells at the onset of forming the lateral lingual swellings, whereas it did not affect the proliferation and differentiation of a myogenic cell lineage, which created a cell community at the central circumferential region of the lateral lingual swellings as seen in vivo and in control cultures lacking the inhibitor. Thus, epithelium-derived Shh signaling stimulates the proliferation of non-myogenic mesenchymal cells essential for forming lateral lingual swellings and contributes to epithelial invagination into the mesenchyme during early tongue development.

  2. Assessment Of Coronary Artery Aneurysms Using Transluminal Attenuation Gradient And Computational Modeling In Kawasaki Disease Patients

    Science.gov (United States)

    Grande Gutierrez, Noelia; Kahn, Andrew; Shirinsky, Olga; Gagarina, Nina; Lyskina, Galina; Fukazawa, Ryuji; Owaga, Shunichi; Burns, Jane; Marsden, Alison

    2015-11-01

    Kawasaki Disease (KD) can result in coronary artery aneurysms (CAA) in up to 25% of patients, putting them at risk of thrombus formation, myocardial infarction and sudden death. Clinical guidelines recommend CAA diameter >8 mm as the arbitrary criterion for initiating systemic anticoagulation. KD patient specific modeling and flow simulations suggest that hemodynamic data can predict regions at increased risk of thrombosis. Transluminal Attenuation Gradient (TAG) is determined from the change in radiological attenuation per vessel length and has been proposed as a non-invasive method for characterizing coronary stenosis from CT Angiography. We hypothesized that CAA abnormal flow could be quantified using TAG. We computed hemodynamics for patient specific coronary models using a stabilized finite element method, coupled numerically to a lumped parameter network to model the heart and vascular boundary conditions. TAG was quantified in the major coronary arteries. We compared TAG for aneurysmal and normal arteries and we analyzed TAG correlation with hemodynamic and geometrical parameters. Our results suggest that TAG may provide hemodynamic data not available from anatomy alone. TAG represents a possible extension to standard CTA that could help to better evaluate the risk of thrombus formation in KD.

  3. Calculation Model of Equivalent Strength for Induced Crack Based on Double-K Fracture Theory and Its Optimizing Setting in RCC Arch Dam

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaogang; SONG Yupu; WU Zhimin

    2005-01-01

    By means of fracture testing on roller-compacted concrete (RCC) three-point bending beams with two different specimen sizes, the P-CMOD complete curve for RCC was gained. Furthermore, by applying double-K fracture theory, KiniⅠC,KunⅠC, as well as the critical effective crack length and the critical crack tip opening displacement, were evaluated. Based on the double-K fracture parameters above, the calculation model of equivalent strength for induced crack was established, thus the calculation method on its initiation, stable propagation and unstable fracture was ascertained. Moreover, the finite element simulation analysis of stress field in ShaPai arch dam and the on-site observational splaying points of induced crack at different altitudes validated the reliability of the model. Finally, crack inducer's optimal setting in RCC arch dam was studied. It improves the design level of induced crack in RCC arch dam and satisfies the necessity of engineering practice.

  4. Induction of continuous expanding infrarenal aortic aneurysms in a large porcine animal model

    DEFF Research Database (Denmark)

    Kloster, Brian Ozeraitis; Lund, Lars; Lindholt, Jes S.

    2015-01-01

    BackgroundA large animal model with a continuous expanding infrarenal aortic aneurysm gives access to a more realistic AAA model with anatomy and physiology similar to humans, and thus allows for new experimental research in the natural history and treatment options of the disease. Methods10 pigs......, hereafter the pigs were euthanized for inspection and AAA wall sampling for histological analysis. ResultsIn group A, all pigs developed continuous expanding AAA’s with a mean increase in AP-diameter to 16.26 ± 0.93 mm equivalent to a 57% increase. In group B the AP-diameters increased to 11.33 ± 0.13 mm...... frequent complication was a neurological deficit in the lower limbs. ConclusionIn pigs it’s possible to induce continuous expanding AAA’s based upon proteolytic degradation and pathological flow, resembling the real life dynamics of human aneurysms. Because the lumbars are preserved, it’s also a potential...

  5. Fractional modeling of viscoelasticity in 3D cerebral arteries and aneurysms

    Science.gov (United States)

    Yu, Yue; Perdikaris, Paris; Karniadakis, George Em

    2016-10-01

    We develop efficient numerical methods for fractional order PDEs, and employ them to investigate viscoelastic constitutive laws for arterial wall mechanics. Recent simulations using one-dimensional models [1] have indicated that fractional order models may offer a more powerful alternative for modeling the arterial wall response, exhibiting reduced sensitivity to parametric uncertainties compared with the integer-calculus-based models. Here, we study three-dimensional (3D) fractional PDEs that naturally model the continuous relaxation properties of soft tissue, and for the first time employ them to simulate flow structure interactions for patient-specific brain aneurysms. To deal with the high memory requirements and in order to accelerate the numerical evaluation of hereditary integrals, we employ a fast convolution method [2] that reduces the memory cost to O (log ⁡ (N)) and the computational complexity to O (Nlog ⁡ (N)). Furthermore, we combine the fast convolution with high-order backward differentiation to achieve third-order time integration accuracy. We confirm that in 3D viscoelastic simulations, the integer order models strongly depends on the relaxation parameters, while the fractional order models are less sensitive. As an application to long-time simulations in complex geometries, we also apply the method to modeling fluid-structure interaction of a 3D patient-specific compliant cerebral artery with an aneurysm. Taken together, our findings demonstrate that fractional calculus can be employed effectively in modeling complex behavior of materials in realistic 3D time-dependent problems if properly designed efficient algorithms are employed to overcome the extra memory requirements and computational complexity associated with the non-local character of fractional derivatives.

  6. Prediction of two month modified Rankin Scale with an ordinal prediction model in patients with aneurysmal subarachnoid haemorrhage

    NARCIS (Netherlands)

    R. Risselada (Roelof); B. Roozenbeek (Bob); A.J. Molyneux (Andrew); R.S.C. Kerr; J. Yarnold (Julia); M. Sneade (Mary); E.W. Steyerberg (Ewout); M.C.J.M. Sturkenboom (Miriam)

    2010-01-01

    textabstractBackground. Aneurysmal subarachnoid haemorrhage (aSAH) is a devastating event with a frequently disabling outcome. Our aim was to develop a prognostic model to predict an ordinal clinical outcome at two months in patients with aSAH. Methods. We studied patients enrolled in the Internatio

  7. Accuracy and precision of polyurethane dental arch models fabricated using a three-dimensional subtractive rapid prototyping method with an intraoral scanning technique

    OpenAIRE

    Kim, Jae-Hong; Kim, Ki-Baek; Kim, Woong-Chul; Kim, Ji-Hwan; Kim, Hae-Young

    2014-01-01

    Objective This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Methods Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP techn...

  8. Correlation between wall shear stress and the rupture of saccular intracranial aneurysms: the initial experimental results with patient-specific 3-D computational model

    International Nuclear Information System (INIS)

    Objective: To find out the hemodynamic factors relating to the rupture of intracranial aneurysm by comparing the hemodynamic parameters of the asymptomatic intracranial aneurysms with that of symptomatic ones. Methods: Eight intracranial aneurysms in five patients were discovered on DSA. By using rotational DSA, 3-D models of the intracranial aneurysms were established, and the numerical simulation of the hemodynamics parameters was performed with finite volume method. The hemodynamics parameters between the aneurysms and the parent arteries were statistically analyzed and compared. Results The average shear stress of the neck and the close parent artery in asymptomatic group was (5.54 ± 2.89) Pa and (6.6 ± 3.47) Pa respectively, while it was (4.78 ± 3.84) Pa and (7.30 ± 3.80) Pa respectively in symptomatic group. No significant difference in the average shear stress of both the aneurysmal neck and its close parent artery existed between two groups (P < 0.05). The low shear stress region of asymptomatic group and symptomatic group was (0.33 ± 0.57)% and (4.72 ± 5.31)% respectively, with a significant difference between the two (P < 0.05). Conclusion: The size of low shear stress region of aneurysmal wall may be one of the main factors causing the rupture of the saccular intracranial aneurysms. (authors)

  9. Modeling and visualization techniques for virtual stenting of aneurysms and stenoses.

    Science.gov (United States)

    Egger, Jan; Grosskopf, Stefan; Nimsky, Christopher; Kapur, Tina; Freisleben, Bernd

    2012-04-01

    In this work, we present modeling and visualization techniques for virtual stenting of aneurysms and stenoses. In particular, contributions to support the computer-aided treatment of artery diseases - artery enlargement (aneurysm) and artery contraction (stenosis) - are made. If an intervention takes place, there are two different treatment alternatives for this kind of artery diseases: open surgery and minimally invasive (endovascular) treatment. Computer-assisted optimization of endovascular treatments is the main focus of our work. In addition to stent simulation techniques, we also present a computer-aided simulation of endoluminal catheters to support the therapy-planning phase. The stent simulation is based on a three-dimensional Active Contour Method and is applicable to both non-bifurcated (I-stents) and bifurcated stents (Y-stents). All methods are introduced in detail and are evaluated with phantom datasets as well as with real patient data from the clinical routine. Additionally, the clinical prototype that is based upon these methods is described.

  10. Three-band decomposition analysis in multiscale FSI models of abdominal aortic aneurysms

    Science.gov (United States)

    Nestola, Maria G. C.; Gizzi, Alessio; Cherubini, Christian; Filippi, Simonetta

    2016-07-01

    Computational modeling plays an important role in biology and medicine to assess the effects of hemodynamic alterations in the onset and development of vascular pathologies. Synthetic analytic indices are of primary importance for a reliable and effective a priori identification of the risk. In this scenario, we propose a multiscale fluid-structure interaction (FSI) modeling approach of hemodynamic flows, extending the recently introduced three-band decomposition (TBD) analysis for moving domains. A quantitative comparison is performed with respect to the most common hemodynamic risk indicators in a systematic manner. We demonstrate the reliability of the TBD methodology also for deformable domains by assuming a hyperelastic formulation of the arterial wall and a Newtonian approximation of the blood flow. Numerical simulations are performed for physiologic and pathologic axially symmetric geometry models with particular attention to abdominal aortic aneurysms (AAAs). Risk assessment, limitations and perspectives are finally discussed.

  11. A comparison of modelling techniques for computing wall stress in abdominal aortic aneurysms

    Directory of Open Access Journals (Sweden)

    McGloughlin Timothy M

    2007-10-01

    Full Text Available Abstract Background Aneurysms, in particular abdominal aortic aneurysms (AAA, form a significant portion of cardiovascular related deaths. There is much debate as to the most suitable tool for rupture prediction and interventional surgery of AAAs, and currently maximum diameter is used clinically as the determining factor for surgical intervention. Stress analysis techniques, such as finite element analysis (FEA to compute the wall stress in patient-specific AAAs, have been regarded by some authors to be more clinically important than the use of a "one-size-fits-all" maximum diameter criterion, since some small AAAs have been shown to have higher wall stress than larger AAAs and have been known to rupture. Methods A patient-specific AAA was selected from our AAA database and 3D reconstruction was performed. The AAA was then modelled in this study using three different approaches, namely, AAA(SIMP, AAA(MOD and AAA(COMP, with each model examined using linear and non-linear material properties. All models were analysed using the finite element method for wall stress distributions. Results Wall stress results show marked differences in peak wall stress results between the three methods. Peak wall stress was shown to reduce when more realistic parameters were utilised. It was also noted that wall stress was shown to reduce by 59% when modelled using the most accurate non-linear complex approach, compared to the same model without intraluminal thrombus. Conclusion The results here show that using more realistic parameters affect resulting wall stress. The use of simplified computational modelling methods can lead to inaccurate stress distributions. Care should be taken when examining stress results found using simplified techniques, in particular, if the wall stress results are to have clinical importance.

  12. Finite Element Modeling of A Novel Self-Expanding Endovascular Stent Method in Treatment of Aortic Aneurysms

    Science.gov (United States)

    Arokiaraj, Mark C.; Palacios, Igor F.

    2014-01-01

    A novel large self-expanding endovascular stent was designed with strut thickness of 70 μm × 70 μm width. The method was developed and investigated to identify a novel simpler technique in aortic aneurysm therapy. Stage 1 analysis was performed after deploying it in a virtual aneurysm model of 6 cm wide × 6 cm long fusiform hyper-elastic anisotropic design. At cell width of 9 mm, there was no buckling or migration of the stent at 180 Hg. Radial force of the stents was estimated after parametric variations. In stage 2 analysis, a prototype 300 μm × 150 μm stent with a cell width of 9 mm was chosen, and it was evaluated similarly after embedding in the aortic wall, and also with a tissue overgrowth of 1 mm over the stent. The 300/150 μm stent reduced the peak wall stress by 70% in the aneurysm and 50% reduction in compliance after embedding. Stage 3 analysis was performed to study the efficacy of stents with struts (thickness/width) 70/70, 180/100 and 300/150 μm after embedding and tissue overgrowth. The adjacent wall stresses were very minimal in stents with 180/100 and 70/70 μm struts after embedding. There is potential for a novel stent method in aortic aneurysm therapy.

  13. Thermal modeling of the NASA-Ames Research Center Cryogenic Optical Test Facility and a single-arch, fused-natural-quartz mirror

    Science.gov (United States)

    Ng, Y. S.; Augason, Gordon C.; Young, Jeffrey A.; Howard, Steven D.; Melugin, Ramsey K.

    1990-01-01

    A thermal model of the dewar and optical system of the Cryogenic Optical Test Facility at NASA-Ames Research Center was developed using the computer codes SINDA and MONTE CARLO. The model was based on the geometry, boundary conditions, and physical properties of the test facility and was developed to investigate heat transfer mechanisms and temperatures in the facility and in test mirrors during cryogenic optical tests. A single-arch, fused-natural-quartz mirror was the first mirror whose thermal loads and temperature distributions were modeled. From the temperature distribution, the thermal gradients in the mirror were obtained. The model predicted that a small gradient should exist for the single arch mirror. This was later verified by the measurement of mirror temperatures. The temperatures, predicted by the model at various locations within the dewar, were in relatively good agreement with the measured temperatures. The model is applicable to both steady-state and transient cooldown operations.

  14. 三维数字化牙模的牙弓线探测%Dental Arch Detection of 3D Dental Model

    Institute of Scientific and Technical Information of China (English)

    袁天然; 廖文和; 戴宁; 崔海华; 王长伟; 俞青

    2008-01-01

    提出了一种在三维数字化牙颌模型上直接探测牙弓线的方法.首先,根据给定的顶点法向和咬合面的夹角阈值过滤出初始特征点,并拟和得到初始牙弓线;其次,对初始特征点集进行等分并找出对应的局部最高顶点,对局部最高顶点进行拟和得到最终的牙弓线.通过对多副牙颌模型的实验表明,所提方法稳定、有效.%A robust detection method for dental arch directly applied on 3D dental model was proposed which could be easily acquired through intra or extra oral measurement methods. Firstly, the initial dental arch was obtained through fitting the initial feature points filtered out according to the given threshold of the angle between the normal of the model point and the occlusal plane. Then the set of the initial feature points was divided into subsets using planes perpendicular to the initial dental arch with equal arch length between each two adjacent planes. The local peak point was found out for each subset according to the distance value between the point of the corresponding subset and the occlusal plane, and the curve fitting to the local peak points was also the final dental arch. The method was tested on models with various types of malocclusions and is proved to be robust and accurate.

  15. Brain aneurysm repair

    Science.gov (United States)

    ... aneurysm repair; Dissecting aneurysm repair; Endovascular aneurysm repair - brain; Subarachnoid hemorrhage - aneurysm ... Your scalp, skull, and the coverings of the brain are opened. A metal clip is placed at ...

  16. Laparo- and thoracoscopic aortic aneurysm neck optimization and treatment of potential endoleaks type IA and II in a porcine model

    Directory of Open Access Journals (Sweden)

    Brian O. Kloster

    2016-02-01

    Conclusion: Using these minimal invasive endoscopic approaches, it seems feasible to externally band aneurysm necks and ligate aortic side branches in a pig model. These procedures could potentially be considered as alternatives to OCs in controlling endoleaks and in improving the safety of endovascular interventions. As endoscopic aortic surgery is challenging a learning curve is expected. Practicing the described procedures using this model, can be used as a learning tool prior to similar interventions on humans.

  17. Conceptual Model Summary Report Simulation Framework for Regional Geologic CO2 Storage Along Arches Province of Midwestern United States

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2011-06-30

    A conceptual model was developed for the Arches Province that integrates geologic and hydrologic information on the Eau Claire and Mt. Simon formations into a geocellular model. The conceptual model describes the geologic setting, stratigraphy, geologic structures, hydrologic features, and distribution of key hydraulic parameters. The conceptual model is focused on the Mt. Simon sandstone and Eau Claire formations. The geocellular model depicts the parameters and conditions in a numerical array that may be imported into the numerical simulations of carbon dioxide (CO2) storage. Geophysical well logs, rock samples, drilling logs, geotechnical test results, and reservoir tests were evaluated for a 500,000 km2 study area centered on the Arches Province. The geologic and hydraulic data were integrated into a three-dimensional (3D) grid of porosity and permeability, which are key parameters regarding fluid flow and pressure buildup due to CO2 injection. Permeability data were corrected in locations where reservoir tests have been performed in Mt. Simon injection wells. The final geocellular model covers an area of 600 km by 600 km centered on the Arches Province. The geocellular model includes a total of 24,500,000 cells representing estimated porosity and permeability distribution. CO2 injection scenarios were developed for on-site and regional injection fields at rates of 70 to 140 million metric tons per year.

  18. Differential Gene Expression in Well-healed and Poorly Healed Experimental Aneurysms after Coil Treatment1

    OpenAIRE

    Kadirvel, Ramanathan; Ding, Yong-Hong; Dai, Daying; Lewis, Debra A.; Kallmes, David F

    2010-01-01

    Increased gene expression in densely packed aneurysms was associated with adhesion molecules, proteases, and cytokines in the rabbit aneurysm model; loosely packed aneurysms showed increased expression of multiple structural molecules, including collagens.

  19. Endovascular Treatment for Proximal Anastomotic Pseudoaneurysm after Total Arch Replacement in Behcet's Disease.

    Science.gov (United States)

    Sakata, Tomoki; Ueda, Hideki; Watanabe, Michiko; Kohno, Hiroki; Tamura, Yusaku; Abe, Shinichiro; Inage, Yuichi; Ikeuchi, Hiroki; Kanda, Tomoyoshi; Fujii, Masahiko; Matsumiya, Goro

    2016-07-01

    A 17-year-old patient underwent total arch replacement for aortic arch aneurysm due to vascular Behcet's disease (BD). Follow-up computed tomography, performed 6 months after the operation, demonstrated pseudoaneurysm formation at the proximal anastomotic site. We performed endovascular treatment and used a short stent graft that was originally designed for abdominal aortic aneurysm. To avoid the occlusion of the coronary or brachiocephalic artery (BCA) due to stent graft migration, we used right ventricular rapid pacing and BCA ballooning. Thus, we believe that endovascular treatment can be used for anastomotic complications in the ascending aorta after open surgery for connective tissue disorders including BD. PMID:27174345

  20. Aortic arch malformations

    Energy Technology Data Exchange (ETDEWEB)

    Kellenberger, Christian J. [University Children' s Hospital, Department of Diagnostic Imaging, Zuerich (Switzerland)

    2010-06-15

    Although anomalies of the aortic arch and its branches are relatively uncommon malformations, they are often associated with congenital heart disease. Isolated lesions may be clinically significant when the airways are compromised by a vascular ring. In this article, the development and imaging appearance of the aortic arch system and its various malformations are reviewed. (orig.)

  1. Lattice Boltzmann Model of 3D Multiphase Flow in Artery Bifurcation Aneurysm Problem.

    Science.gov (United States)

    Abas, Aizat; Mokhtar, N Hafizah; Ishak, M H H; Abdullah, M Z; Ho Tian, Ang

    2016-01-01

    This paper simulates and predicts the laminar flow inside the 3D aneurysm geometry, since the hemodynamic situation in the blood vessels is difficult to determine and visualize using standard imaging techniques, for example, magnetic resonance imaging (MRI). Three different types of Lattice Boltzmann (LB) models are computed, namely, single relaxation time (SRT), multiple relaxation time (MRT), and regularized BGK models. The results obtained using these different versions of the LB-based code will then be validated with ANSYS FLUENT, a commercially available finite volume- (FV-) based CFD solver. The simulated flow profiles that include velocity, pressure, and wall shear stress (WSS) are then compared between the two solvers. The predicted outcomes show that all the LB models are comparable and in good agreement with the FVM solver for complex blood flow simulation. The findings also show minor differences in their WSS profiles. The performance of the parallel implementation for each solver is also included and discussed in this paper. In terms of parallelization, it was shown that LBM-based code performed better in terms of the computation time required. PMID:27239221

  2. Lattice Boltzmann Model of 3D Multiphase Flow in Artery Bifurcation Aneurysm Problem

    Directory of Open Access Journals (Sweden)

    Aizat Abas

    2016-01-01

    Full Text Available This paper simulates and predicts the laminar flow inside the 3D aneurysm geometry, since the hemodynamic situation in the blood vessels is difficult to determine and visualize using standard imaging techniques, for example, magnetic resonance imaging (MRI. Three different types of Lattice Boltzmann (LB models are computed, namely, single relaxation time (SRT, multiple relaxation time (MRT, and regularized BGK models. The results obtained using these different versions of the LB-based code will then be validated with ANSYS FLUENT, a commercially available finite volume- (FV- based CFD solver. The simulated flow profiles that include velocity, pressure, and wall shear stress (WSS are then compared between the two solvers. The predicted outcomes show that all the LB models are comparable and in good agreement with the FVM solver for complex blood flow simulation. The findings also show minor differences in their WSS profiles. The performance of the parallel implementation for each solver is also included and discussed in this paper. In terms of parallelization, it was shown that LBM-based code performed better in terms of the computation time required.

  3. Multilocular True Ulnar Artery Aneurysm in a Pediatric Patient.

    Science.gov (United States)

    Stalder, Mark W; Sanders, Christopher; Lago, Mary; Hilaire, Hugo St

    2016-01-01

    Ulnar artery aneurysms are an exceedingly rare entity in the pediatric population and have no consistent etiologic mechanism. We present the case of a 15-year-old male with a multilocular ulnar artery aneurysm in the setting of no antecedent history of trauma, no identifiable connective tissue disorders, and no other apparent etiological factors. Furthermore, the patient's arterial palmar arch system was absent. The aneurysm was resected, and arterial reconstruction was successfully performed via open surgical approach with cephalic vein interposition graft. We believe this treatment modality should be considered as the primary approach in all of these pediatric cases in consideration of the possible pitfalls of less comprehensive measures.

  4. Predicting microbial water quality with models:over-arching questions for managing risk in agricultural catchments

    OpenAIRE

    Oliver, David Michael; Porter, Kenneth D. H.; Pachepsky, Yakov A.; Muirhead, Richard W.; Reaney, Sim M.; Coffey, Rory; Kay, David; Milledge, David Graham; Hong, Eunmi; Steven G Anthony; Page, Trevor John Charles; Bloodworth, Jack W.; Mellander, Per-Erik; Carbonneau, Patrice E.; McGrane, Scott J.

    2016-01-01

    The application of models to predict concentrations of faecal indicator organisms (FIOs) in environmental systems plays an important role for guiding decision-making associated with the management of microbial water quality. In recent years there has been an increasing demand by policy-makers for models to help inform FIO dynamics in order to prioritise efforts for environmental and human-health protection. However, given the limited evidence-base on which FIO models are built relative to oth...

  5. Nonlinear Dynamics of Electrostatically Actuated MEMS Arches

    KAUST Repository

    Al Hennawi, Qais M.

    2015-05-01

    In this thesis, we present theoretical and experimental investigation into the nonlinear statics and dynamics of clamped-clamped in-plane MEMS arches when excited by an electrostatic force. Theoretically, we first solve the equation of motion using a multi- mode Galarkin Reduced Order Model (ROM). We investigate the static response of the arch experimentally where we show several jumps due to the snap-through instability. Experimentally, a case study of in-plane silicon micromachined arch is studied and its mechanical behavior is measured using optical techniques. We develop an algorithm to extract various parameters that are needed to model the arch, such as the induced axial force, the modulus of elasticity, and the initially induced initial rise. After that, we excite the arch by a DC electrostatic force superimposed to an AC harmonic load. A softening spring behavior is observed when the excitation is close to the first resonance frequency due to the quadratic nonlinearity coming from the arch geometry and the electrostatic force. Also, a hardening spring behavior is observed when the excitation is close to the third (second symmetric) resonance frequency due to the cubic nonlinearity coming from mid-plane stretching. Then, we excite the arch by an electric load of two AC frequency components, where we report a combination resonance of the summed type. Agreement is reported among the theoretical and experimental work.

  6. CFD Modelling of Abdominal Aortic Aneurysm on Hemodynamic Loads Using a Realistic Geometry with CT

    Directory of Open Access Journals (Sweden)

    Eduardo Soudah

    2013-01-01

    Full Text Available The objective of this study is to find a correlation between the abdominal aortic aneurysm (AAA geometric parameters, wall stress shear (WSS, abdominal flow patterns, intraluminal thrombus (ILT, and AAA arterial wall rupture using computational fluid dynamics (CFD. Real AAA 3D models were created by three-dimensional (3D reconstruction of in vivo acquired computed tomography (CT images from 5 patients. Based on 3D AAA models, high quality volume meshes were created using an optimal tetrahedral aspect ratio for the whole domain. In order to quantify the WSS and the recirculation inside the AAA, a 3D CFD using finite elements analysis was used. The CFD computation was performed assuming that the arterial wall is rigid and the blood is considered a homogeneous Newtonian fluid with a density of 1050 kg/m3 and a kinematic viscosity of 4×10-3 Pa·s. Parallelization procedures were used in order to increase the performance of the CFD calculations. A relation between AAA geometric parameters (asymmetry index (β, saccular index (γ, deformation diameter ratio (χ, and tortuosity index (ε and hemodynamic loads was observed, and it could be used as a potential predictor of AAA arterial wall rupture and potential ILT formation.

  7. Fluid-Structure Interaction Modeling of Intracranial Aneurysm Hemodynamics: Effects of Different Assumptions

    Science.gov (United States)

    Rajabzadeh Oghaz, Hamidreza; Damiano, Robert; Meng, Hui

    2015-11-01

    Intracranial aneurysms (IAs) are pathological outpouchings of cerebral vessels, the progression of which are mediated by complex interactions between the blood flow and vasculature. Image-based computational fluid dynamics (CFD) has been used for decades to investigate IA hemodynamics. However, the commonly adopted simplifying assumptions in CFD (e.g. rigid wall) compromise the simulation accuracy and mask the complex physics involved in IA progression and eventual rupture. Several groups have considered the wall compliance by using fluid-structure interaction (FSI) modeling. However, FSI simulation is highly sensitive to numerical assumptions (e.g. linear-elastic wall material, Newtonian fluid, initial vessel configuration, and constant pressure outlet), the effects of which are poorly understood. In this study, a comprehensive investigation of the sensitivity of FSI simulations in patient-specific IAs is investigated using a multi-stage approach with a varying level of complexity. We start with simulations incorporating several common simplifications: rigid wall, Newtonian fluid, and constant pressure at the outlets, and then we stepwise remove these simplifications until the most comprehensive FSI simulations. Hemodynamic parameters such as wall shear stress and oscillatory shear index are assessed and compared at each stage to better understand the sensitivity of in FSI simulations for IA to model assumptions. Supported by the National Institutes of Health (1R01 NS 091075-01).

  8. CFD Modelling of Abdominal Aortic Aneurysm on Hemodynamic Loads Using a Realistic Geometry with CT

    Science.gov (United States)

    Ng, E. Y. K.; Loong, T. H.; Bordone, Maurizio; Pua, Uei; Narayanan, Sriram

    2013-01-01

    The objective of this study is to find a correlation between the abdominal aortic aneurysm (AAA) geometric parameters, wall stress shear (WSS), abdominal flow patterns, intraluminal thrombus (ILT), and AAA arterial wall rupture using computational fluid dynamics (CFD). Real AAA 3D models were created by three-dimensional (3D) reconstruction of in vivo acquired computed tomography (CT) images from 5 patients. Based on 3D AAA models, high quality volume meshes were created using an optimal tetrahedral aspect ratio for the whole domain. In order to quantify the WSS and the recirculation inside the AAA, a 3D CFD using finite elements analysis was used. The CFD computation was performed assuming that the arterial wall is rigid and the blood is considered a homogeneous Newtonian fluid with a density of 1050 kg/m3 and a kinematic viscosity of 4 × 10−3 Pa·s. Parallelization procedures were used in order to increase the performance of the CFD calculations. A relation between AAA geometric parameters (asymmetry index (β), saccular index (γ), deformation diameter ratio (χ), and tortuosity index (ε)) and hemodynamic loads was observed, and it could be used as a potential predictor of AAA arterial wall rupture and potential ILT formation. PMID:23864906

  9. Bacteroides fragilis aortic arch pseudoaneurysm: case report with review

    Directory of Open Access Journals (Sweden)

    Yang Yu-Jen

    2008-05-01

    Full Text Available Abstract We present a case of 58-year-old woman with underlying diabetes mellitus, hepatitis C virus-related liver cirrhosis, and total hysterectomy for uterine myoma 11 moths ago, who was diagnosed ruptured aortic arch mycotic pseudoaneurysm after a certain period of survey for her unknown fever cause. After emergent surgery with prosthetic graft interposition, all her blood cultures and tissue cultures revealed pathogen with Bacteroides fragilis. Although mycotic aneurysms have been well described in literatures, an aneurysm infected solely with Bacteroides fragilis is unusual, with only eight similar cases in the literature. Here we reported the only female case with her specific clinical and management course and summarized all reported cases of mycotic aneurysm caused by Bacteroides fragilis to clarify their conditions and treatments, alert the difficulty in diagnosis, and importance of highly suspicious.

  10. Determining rural risk for aneurysmal subarachnoid hemorrhages: A structural equation modeling approach

    Science.gov (United States)

    Nichols, Linda Jayne; Gall, Seana; Stirling, Christine

    2016-01-01

    An aneurysmal subarachnoid hemorrhage (aSAH) carries a high disability burden. The true impact of rurality as a predictor of outcome severity is unknown. Our aim is to clarify the relationship between the proposed explanations of regional and rural health disparities linked to severity of outcome following an aSAH. An initial literature search identified limited data directly linking geographical location, rurality, rural vulnerability, and aSAH. A further search noting parallels with ischemic stroke and acute myocardial infarct literature presented a number of diverse and interrelated predictors. This a priori knowledge informed the development of a conceptual framework that proposes the relationship between rurality and severity of outcome following an aSAH utilizing structural equation modeling. The presented conceptual framework explores a number of system, environmental, and modifiable risk factors. Socioeconomic characteristics, modifiable risk factors, and timely treatment that were identified as predictors of severity of outcome following an aSAH and within each of these defined predictors a number of contributing specific individual predictors are proposed. There are considerable gaps in the current knowledge pertaining to the impact of rurality on the severity of outcome following an aSAH. Absent from the literature is any investigation of the cumulative impact and multiplicity of risk factors associated with rurality. The proposed conceptual framework hypothesizes a number of relationships between both individual level and system level predictors, acknowledging that intervening predictors may mediate the effect of one variable on another. PMID:27695237

  11. Determining rural risk for aneurysmal subarachnoid hemorrhages: A structural equation modeling approach

    Directory of Open Access Journals (Sweden)

    Linda Jayne Nichols

    2016-01-01

    Full Text Available An aneurysmal subarachnoid hemorrhage (aSAH carries a high disability burden. The true impact of rurality as a predictor of outcome severity is unknown. Our aim is to clarify the relationship between the proposed explanations of regional and rural health disparities linked to severity of outcome following an aSAH. An initial literature search identified limited data directly linking geographical location, rurality, rural vulnerability, and aSAH. A further search noting parallels with ischemic stroke and acute myocardial infarct literature presented a number of diverse and interrelated predictors. This a priori knowledge informed the development of a conceptual framework that proposes the relationship between rurality and severity of outcome following an aSAH utilizing structural equation modeling. The presented conceptual framework explores a number of system, environmental, and modifiable risk factors. Socioeconomic characteristics, modifiable risk factors, and timely treatment that were identified as predictors of severity of outcome following an aSAH and within each of these defined predictors a number of contributing specific individual predictors are proposed. There are considerable gaps in the current knowledge pertaining to the impact of rurality on the severity of outcome following an aSAH. Absent from the literature is any investigation of the cumulative impact and multiplicity of risk factors associated with rurality. The proposed conceptual framework hypothesizes a number of relationships between both individual level and system level predictors, acknowledging that intervening predictors may mediate the effect of one variable on another.

  12. Flow investigation in sidewall aneurysm model using a novel PIV multi-time-lag method

    Science.gov (United States)

    Bouillot, Pierre; Brina, Olivier; Ouared, Rafik; Lovblad, Karl-Olof; Mendes Pereira, Vitor; Farhat, Mohamed

    2013-11-01

    The intracranial aneurysm (IA) lesion is one of the main causes of intracranial hemorrhage in productive population. It is well known that the hemodynamic factors have large impact on both the IAs rupture and treatment efficacy based on flow diverter stents. Precise experimental investigations of blood flow in IAs using particle imaging velocimetry (PIV) are therefore strongly required in order to validate clinical treatments based on computational and clinical flow assessment tools. Due to the large variations of flow velocities in IAs, a single PIV measurement with a unique time lag between two consecutive images cannot provide a good level of precision in all the measured volume. In this work, we implement an error analysis based on several PIV measurements with different time lags to ensure an optimal precision in the entire measurement volume. This PIV multi-time-lag method is applied on a sidewall IA model to investigate the effect of the inflow pulsatility. By comparing the flow patterns resulting from steady and unsteady inflows we point out important differences which could be involved in the IAs evolution. In particular, the blood transfer in the IA and the vortical structure are significantly modified when increasing the pulsatility compared to quasi-steady conditions.

  13. Determining rural risk for aneurysmal subarachnoid hemorrhages: A structural equation modeling approach

    Science.gov (United States)

    Nichols, Linda Jayne; Gall, Seana; Stirling, Christine

    2016-01-01

    An aneurysmal subarachnoid hemorrhage (aSAH) carries a high disability burden. The true impact of rurality as a predictor of outcome severity is unknown. Our aim is to clarify the relationship between the proposed explanations of regional and rural health disparities linked to severity of outcome following an aSAH. An initial literature search identified limited data directly linking geographical location, rurality, rural vulnerability, and aSAH. A further search noting parallels with ischemic stroke and acute myocardial infarct literature presented a number of diverse and interrelated predictors. This a priori knowledge informed the development of a conceptual framework that proposes the relationship between rurality and severity of outcome following an aSAH utilizing structural equation modeling. The presented conceptual framework explores a number of system, environmental, and modifiable risk factors. Socioeconomic characteristics, modifiable risk factors, and timely treatment that were identified as predictors of severity of outcome following an aSAH and within each of these defined predictors a number of contributing specific individual predictors are proposed. There are considerable gaps in the current knowledge pertaining to the impact of rurality on the severity of outcome following an aSAH. Absent from the literature is any investigation of the cumulative impact and multiplicity of risk factors associated with rurality. The proposed conceptual framework hypothesizes a number of relationships between both individual level and system level predictors, acknowledging that intervening predictors may mediate the effect of one variable on another.

  14. Photographs of dental casts or digital models: rating dental arch relationships in bilateral cleft lip and palate.

    NARCIS (Netherlands)

    Leenarts, C.M.; Bartzela, T.N.; Bronkhorst, E.M.; Semb, G.; Shaw, W.C.; Katsaros, C.; Kuijpers-Jagtman, A.M.

    2012-01-01

    Yardsticks have been developed to measure dental arch relations in cleft lip and palate (CLP) patients as diagnostic proxies for the underlying skeletal relationship. Travelling with plaster casts to compare results between CLP centres is inefficient so the aim of this study was to investigate the r

  15. Vertebral artery aneurysms.

    Directory of Open Access Journals (Sweden)

    Ravi Kumar C

    2000-04-01

    Full Text Available Vertebral artery (VA aneurysms are rare. We present our experience with three cases of VA aneurysms. Two aneurysms were located close to the origin of basilar artery while the third patient had a giant posterior inferior cerebellar artery aneurysm. These aneurysms were operated by the far lateral inferior suboccipital approach with good results.

  16. Prediction of two month modified Rankin Scale with an ordinal prediction model in patients with aneurysmal subarachnoid haemorrhage

    Directory of Open Access Journals (Sweden)

    Sneade Mary

    2010-09-01

    Full Text Available Abstract Background Aneurysmal subarachnoid haemorrhage (aSAH is a devastating event with a frequently disabling outcome. Our aim was to develop a prognostic model to predict an ordinal clinical outcome at two months in patients with aSAH. Methods We studied patients enrolled in the International Subarachnoid Aneurysm Trial (ISAT, a randomized multicentre trial to compare coiling and clipping in aSAH patients. Several models were explored to estimate a patient's outcome according to the modified Rankin Scale (mRS at two months after aSAH. Our final model was validated internally with bootstrapping techniques. Results The study population comprised of 2,128 patients of whom 159 patients died within 2 months (8%. Multivariable proportional odds analysis identified World Federation of Neurosurgical Societies (WFNS grade as the most important predictor, followed by age, sex, lumen size of the aneurysm, Fisher grade, vasospasm on angiography, and treatment modality. The model discriminated moderately between those with poor and good mRS scores (c statistic = 0.65, with minor optimism according to bootstrap re-sampling (optimism corrected c statistic = 0.64. Conclusion We presented a calibrated and internally validated ordinal prognostic model to predict two month mRS in aSAH patients who survived the early stage up till a treatment decision. Although generalizability of the model is limited due to the selected population in which it was developed, this model could eventually be used to support clinical decision making after external validation. Trial Registration International Standard Randomised Controlled Trial, Number ISRCTN49866681

  17. Evaluation of dental arch width and form changes after orthodontic treatment and retention with a new computerized method.

    Science.gov (United States)

    Taner, Tülin Ugur; Ciger, Semra; El, Hakan; Germeç, Derya; Es, Alphan

    2004-10-01

    The purpose of this study was to evaluate longitudinal arch width and form changes and to define arch form types with a new computerized method. Maxillary and mandibular models of 21 Class II Division 1 patients were examined before treatment (T(0)), after treatment (T(1)), and an average of 3 years after retention (T(2)). Arch width measurements were made directly on scanned images of maxillary and mandibular models. Arch form changes at T(0)-T(1) and T(1)-T(2) were evaluated by superimposing the computer-generated Bezier arch curves with a computer program. Types of dental arch forms were defined by superimposing them with the pentamorphic arch system, which included 5 different types of arch forms: normal, ovoid, tapered, narrow ovoid, and narrow tapered. Maxillary arch widths were increased during orthodontic treatment. Mandibular posterior arch widths were also increased. The expansion of the mandibular arch forms was less than in the maxillary arch forms. Arch width changes were generally stable, except for reduction in maxillary and mandibular interlateral, inter-first premolar, and mandibular intercanine widths. Pretreatment maxillary arch forms were mostly tapered; mandibular arch forms were tapered and narrow tapered. In maxillary arch forms, 76% of the treatment changes were maintained. Mandibular arch form was maintained in 67% of the sample, both during treatment and after retention. In mandibular arches, 71% of orthodontically induced arch form changes were maintained. PMID:15470349

  18. Evolution Characteristic Analysis of Pressure-arch of a Double-arch Tunnel in Water-rich Strata

    Directory of Open Access Journals (Sweden)

    C. L. Li

    2016-03-01

    Full Text Available It is of importance to analyze the morphological characterization, the evolution process and the skewed effect of pressure-arch of a double-arch tunnel in the water-rich strata. Taking a buried depth 80 m double-arch tunnel as an example, a computational model of the double-arch tunnel was built by using FLAC3D technique. Then considering some aspects including groundwater conditions, tunnel depth, construction sequences and permeability coefficients, the coupling effect of stress field and seepage field in the pressure-arch of the double-arch tunnel was analyzed. The results show that the thickness of the pressure-arch induced by step-by-step excavation and display a step-descent skewed distribution from the left to the right of the double-arch tunnel. The permeability coefficient has a significant influence on the shape and the skewed effect of the pressure arch. The excavation of the bench method has a better arching condition than that of the expanding method. The abtained results provide a basic reference for the rock reinforcement design and safety construction of double-arch tunnels in the water-rich strata.

  19. Aortic aneurysm repair - endovascular

    Science.gov (United States)

    EVAR; Endovascular aneurysm repair - aorta; AAA repair - endovascular; Repair - aortic aneurysm - endovascular ... Endovascular aortic repair is done because your aneurysm is very large, growing quickly, or is leaking or bleeding. You may have ...

  20. Pathogenic sequence for dissecting aneurysm formation in a hypomorphic polycystic kidney disease 1 mouse model

    NARCIS (Netherlands)

    Hassane, S.; Claij, N.; Lantinga-van Leeuwen, I.S.; Munsteren, J.C. van; Lent, N. van; Hanemaaijer, R.; Breuning, M.H.; Peters, D.J.M.; Ruiter, M.C. de

    2007-01-01

    OBJECTIVE - Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a multi-system disorder characterized by progressive cyst formation in the kidneys. Serious complications of ADPKD are intracranial and aortic aneurysms. The condition is mainly caused by mutations in the PKD1 or PKD2 gene. We have

  1. Abdominal Aortic Aneurysms: Treatments

    Science.gov (United States)

    ... access catheters Vertebroplasty Women and vascular disease Women's health Social Media Facebook Twitter ... Abdominal Aortic Aneurysms Interventional Radiologists Treat Abdominal Aneurysms Nonsurgically Interventional radiologists are vascular ...

  2. Fluid, solid and fluid-structure interaction simulations on patient-based abdominal aortic aneurysm models.

    Science.gov (United States)

    Kelly, Sinead; O'Rourke, Malachy

    2012-04-01

    This article describes the use of fluid, solid and fluid-structure interaction simulations on three patient-based abdominal aortic aneurysm geometries. All simulations were carried out using OpenFOAM, which uses the finite volume method to solve both fluid and solid equations. Initially a fluid-only simulation was carried out on a single patient-based geometry and results from this simulation were compared with experimental results. There was good qualitative and quantitative agreement between the experimental and numerical results, suggesting that OpenFOAM is capable of predicting the main features of unsteady flow through a complex patient-based abdominal aortic aneurysm geometry. The intraluminal thrombus and arterial wall were then included, and solid stress and fluid-structure interaction simulations were performed on this, and two other patient-based abdominal aortic aneurysm geometries. It was found that the solid stress simulations resulted in an under-estimation of the maximum stress by up to 5.9% when compared with the fluid-structure interaction simulations. In the fluid-structure interaction simulations, flow induced pressure within the aneurysm was found to be up to 4.8% higher than the value of peak systolic pressure imposed in the solid stress simulations, which is likely to be the cause of the variation in the stress results. In comparing the results from the initial fluid-only simulation with results from the fluid-structure interaction simulation on the same patient, it was found that wall shear stress values varied by up to 35% between the two simulation methods. It was concluded that solid stress simulations are adequate to predict the maximum stress in an aneurysm wall, while fluid-structure interaction simulations should be performed if accurate prediction of the fluid wall shear stress is necessary. Therefore, the decision to perform fluid-structure interaction simulations should be based on the particular variables of interest in a given

  3. Wall shear stress in intracranial aneurysms and adjacent arteries

    Institute of Scientific and Technical Information of China (English)

    Fuyu Wang; Bainan Xu; Zhenghui Sun; Chen Wu; Xiaojun Zhang

    2013-01-01

    Hemodynamic parameters play an important role in aneurysm formation and growth. However, it is difficult to directly observe a rapidly growing de novo aneurysm in a patient. To investigate possible associations between hemodynamic parameters and the formation and growth of intracranial aneurysms, the present study constructed a computational model of a case with an internal carotid artery aneurysm and an anterior communicating artery aneurysm, based on the CT angiography findings of a patient. To simulate the formation of the anterior communicating artery aneurysm and the growth of the internal carotid artery aneurysm, we then constructed a model that virtually removed the anterior communicating artery aneurysm, and a further two models that also progressively decreased the size of the internal carotid artery aneurysm. Computational simulations of the fluid dynamics of the four models were performed under pulsatile flow conditions, and wall shear stress was compared among the different models. In the three aneurysm growth models, increasing size of the aneurysm was associated with an increased area of low wall shear stress, a significant decrease in wall shear stress at the dome of the aneurysm, and a significant change in the wall shear stress of the parent artery. The wall shear stress of the anterior communicating artery remained low, and was significantly lower than the wall shear stress at the bifurcation of the internal carotid artery or the bifurcation of the middle cerebral artery. After formation of the anterior communicating artery aneurysm, the wall shear stress at the dome of the internal carotid artery aneurysm increased significantly, and the wall shear stress in the upstream arteries also changed significantly. These findings indicate that low wall shear stress may be associated with the initiation and growth of aneurysms, and that aneurysm formation and growth may influence hemodynamic parameters in the local and adjacent arteries.

  4. Antibody directs properdin-dependent activation of the complement alternative pathway in a mouse model of abdominal aortic aneurysm.

    Science.gov (United States)

    Zhou, Hui-Fang; Yan, Huimin; Stover, Cordula M; Fernandez, Tamara Montes; Rodriguez de Cordoba, Santiago; Song, Wen-Chao; Wu, Xiaobo; Thompson, Robert W; Schwaeble, Wilhelm J; Atkinson, John P; Hourcade, Dennis E; Pham, Christine T N

    2012-02-14

    Abdominal aortic aneurysm (AAA) is a complex inflammatory vascular disease. There are currently limited treatment options for AAA when surgery is inapplicable. Therefore, insights into molecular mechanisms underlying AAA pathogenesis may reveal therapeutic targets that could be manipulated pharmacologically or biologically to halt disease progression. Using an elastase-induced AAA mouse model, we previously established that the complement alternative pathway (AP) plays a critical role in the development of AAA. However, the mechanism by which complement AP is initiated remains undefined. The complement protein properdin, traditionally viewed as a positive regulator of the AP, may also initiate complement activation by binding directly to target surfaces. In this study, we sought to determine whether properdin serves as a focal point for the initiation of the AP complement activation in AAA. Using a properdin loss of function mutation in mice and a mutant form of the complement factor B protein that produces a stable, properdin-free AP C3 convertase, we show that properdin is required for the development of elastase-induced AAA in its primary role as a convertase stabilizer. Unexpectedly, we find that, in AAA, natural IgG antibodies direct AP-mediated complement activation. The absence of IgG abrogates C3 deposition in elastase-perfused aortic wall and protects animals from AAA development. We also determine that blockade of properdin activity prevents aneurysm formation. These results indicate that an innate immune response to self-antigens activates the complement system and initiates the inflammatory cascade in AAA. Moreover, the study suggests that properdin-targeting strategies may halt aneurysmal growth.

  5. The interactions between bloodstream and vascular structure on aortic dissecting aneurysmal model: A numerical study

    Science.gov (United States)

    Chen, Zeng-Sheng; Fan, Zhan-Ming; Zhang, Xi-Wen

    2013-06-01

    Stent-graft implantation is an important means of clinical treatment for aortic dissecting aneurysm (ADA). However, researches on fluid dynamics effects of stent were rare. Computer simulation was used to investigate the interactions between bloodstream and vascular structure in a stented ADA, which endures the periodic pulse velocity and pressure. We obtained and analyzed the flow velocity distribution, the wall displacement and wall stress in the ADA. By comparing the different results between a non-stented and a stented ADA, we found that the insertion of a vascular graft can make the location of maximum stress and displacement move from the aneurysm lumen wall to the artery wall, accompanied with a greatly decrease in value. These results imply that the placement of a stent-graft of any kind to occlude ADA will result in a decreased chance of rupture.

  6. Clipping techniques in cerebral aneurysm surgery.

    Science.gov (United States)

    Acciarri, Nicola; Toniato, Giovanni; Raabe, Andreas; Lanzino, Giuseppe

    2016-03-01

    The history of cerebral aneurysm surgery owes a great tribute to the tenacity of pioneering neurosurgeons who designed and developed the clips used to close the aneurysms neck. However, until the beginning of the past century, surgery of complex and challenging aneurysms was impossible due to the lack of surgical microscope and commercially available sophisticated clips. The modern era of the spring clips began in the second half of last century. Until then, only malleable metal clips and other non-metallic materials were available for intracranial aneurysms. Indeed, the earliest clips were hazardous and difficult to handle. Several neurosurgeons put their effort in developing new clip models, based on their personal experience in the treatment of cerebral aneurysms. Finally, the introduction of the surgical microscope, together with the availability of more sophisticated clips, has allowed the treatment of complex and challenging aneurysms. However, today none of the new instruments or tools for surgical therapy of aneurysms could be used safely and effectively without keeping in mind the lessons on innovative surgical techniques provided by great neurovascular surgeons. Thanks to their legacy, we can now treat many types of aneurysms that had always been considered inoperable. In this article, we review the basic principles of surgical clipping and illustrate some more advanced techniques to be used for complex aneurysms. PMID:26657306

  7. QueryArch3D: Querying and Visualising 3D Models of a Maya Archaeological Site in a Web-Based Interface

    Directory of Open Access Journals (Sweden)

    Giorgio Agugiaro

    2011-12-01

    Full Text Available Constant improvements in the field of surveying, computing and distribution of digital-content are reshaping the way Cultural Heritage can be digitised and virtually accessed, even remotely via web. A traditional 2D approach for data access, exploration, retrieval and exploration may generally suffice, however more complex analyses concerning spatial and temporal features require 3D tools, which, in some cases, have not yet been implemented or are not yet generally commercially available. Efficient organisation and integration strategies applicable to the wide array of heterogeneous data in the field of Cultural Heritage represent a hot research topic nowadays. This article presents a visualisation and query tool (QueryArch3D conceived to deal with multi-resolution 3D models. Geometric data are organised in successive levels of detail (LoD, provided with geometric and semantic hierarchies and enriched with attributes coming from external data sources. The visualisation and query front-end enables the 3D navigation of the models in a virtual environment, as well as the interaction with the objects by means of queries based on attributes or on geometries. The tool can be used as a standalone application, or served through the web. The characteristics of the research work, along with some implementation issues and the developed QueryArch3D tool will be discussed and presented.

  8. An Electrostatically Actuated MEMS Arch Band-Pass Filter

    Directory of Open Access Journals (Sweden)

    Hassen M. Ouakad

    2013-01-01

    Full Text Available This work presents an investigation of the dynamics of micromachined arches resonators and their potential to be utilized as band-pass filters. The arches are actuated by a DC electrostatic load superimposed to an AC harmonic load. The dynamic response of the arch is studied analytically using a Galerkin-based reduced-order model when excited near its fundamental and third natural frequencies. Several simulation results are presented demonstrating interesting jumps and snap-through behavior of the arches and their attractive features for uses as band-pass filters, such as their sharp roll-off from pass bands to stop bands and their flat response.

  9. Time evolution and hemodynamics of cerebral aneurysms

    Science.gov (United States)

    Sforza, Daniel M.; Putman, Christopher; Tateshima, Satoshi; Viñuela, Fernando; Cebral, Juan

    2011-03-01

    Cerebral aneurysm rupture is a leading cause of hemorrhagic strokes. Because they are being more frequently diagnosed before rupture and the prognosis of subarachnoid hemorrhage is poor, clinicians are often required to judge which aneurysms are prone to progression and rupture. Unfortunately, the processes of aneurysm initiation, growth and rupture are not well understood. Multiple factors associated to these processes have been identified. Our goal is to investigate two of them, arterial hemodynamics (using computational fluid dynamics) and the peri-aneurysmal environment, by studying a group of growing cerebral aneurysms that are followed longitudinally in time. Six patients with unruptured untreated brain aneurysms which exhibited growth during the observation period were selected for the study. Vascular models of each aneurysm at each observation time were constructed from the corresponding computed tomography angiography (CTA) images. Subsequently, models were aligned, and geometrical differences quantified. Blood flow was modeled with the 3D unsteady incompressible Navier-Stokes equation for a Newtonian fluid, and wall shear stress distribution and flow patterns were calculated and visualized. Analysis of the simulations and changes in geometry revealed asymmetric growth patterns and suggests that areas subject to vigorous flows, i.e. relative high wall shear stress and concentrated streamlines patterns; correspond to regions of aneurysm growth. Furthermore, in some cases the geometrical evolution of aneurysms is clearly affected by contacts with bone structures and calcifications in the wall, and as a consequence the hemodynamics is greatly modified. Thus, in these cases the peri-aneurysmal environment must be considered when analyzing aneurysm evolution.

  10. Influencing factors of immediate angiographic results in intracranial aneurysms patients after endovascular treatment.

    Science.gov (United States)

    Chen, Jia-Xiang; Lai, Ling-Feng; Zheng, Kuang; Li, Guo-Xiong; He, Xu-Ying; Li, Liang-Ping; Duan, Chuan-Zhi

    2015-09-01

    The purpose of this study was to analyze influencing factors associated with immediate angiographic results in intracranial aneurysms patients after endovascular treatment (EVT), providing theoretical evidence and guidance for clinical treatment of intracranial aneurysms. Totally 529 patients met the inclusive criteria, consisting of 338 males and 191 females. Gender; age; history of hypertension, diabetes, and smoking; intracranial atherosclerosis; rupture status, size and location, features of aneurysmal neck, shapes; vasospasm; treatment modality; and degree of aneurysm occlusion were all carefully and completely recorded. All data were investigated in univariate and multivariate logistic regression model to determine whether they were correlated with the degree of aneurysm occlusion. According to aneurysm size, aneurysms were classified as micro-miniature, miniature, and large aneurysms. There were 451 narrow-neck aneurysms and 78 wide-neck aneurysms. Totally 417 were regular and 112 were irregular. And 125 were un-ruptured aneurysms; 404 were ruptured aneurysms. The modalities of treatment were as follows: embolization with coil (n = 415), stent-assisted coil embolization (n = 89), and balloon-assisted coil embolization (n = 25). Univariate analysis showed that aneurysm size, feature of aneurysm neck, shape, and rupture status might affect the immediate occlusion after EVT. Multivariate logistic regression analysis indicated that ruptured aneurysm, tiny aneurysm, and wide-neck aneurysm were independent influencing factors of complete occlusion of intracranial aneurysm. Aneurysm rupture status, size, feature of aneurysmal neck, and shape might be the independent influencing factors of immediate angiographic results in intracranial aneurysm patients after EVT. Un-ruptured, micro-miniature, narrow-neck, and regular-shaped aneurysms were more probable to be occluded completely. PMID:26100332

  11. [Aortic aneurysm].

    Science.gov (United States)

    Villar, Fernando; Pedro-Botet, Juan; Vila, Ramón; Lahoz, Carlos

    2013-01-01

    Aortic aneurysm is one important cause of death in our country. The prevalence of abdominal aortic aneurism (AAA) is around 5% for men older than 50 years of age. Some factors are associated with increased risk for AAA: age, hypertension, hypercholesterolemia, cardiovascular disease and, in particular, smoking. The medical management of patients with an AAA includes cardiovascular risk treatment, particularly smoking cessation. Most of major societies guidelines recommend ultrasonography screening for AAA in men aged 65 to 75 years who have ever smoked because it leads to decreased AAA-specific mortality. PMID:24238836

  12. Tubular Steel Arch Stabilized by Textile Membranes

    Directory of Open Access Journals (Sweden)

    Ondrej Svoboda

    2016-10-01

    Full Text Available Tubular steel arch supporting textile membrane roofing is investigated experimentally and numerically. The stabilization effects of the textile membrane on in-plane and out-of-plane behavior of the arch is of primary interest. First a model of a large membrane structure tested in laboratory is described. Prestressed membranes of PVC coated polyester fabric Ferrari® Précontraint 702S were used as a currently standard and excellent material. The test arrangement, loading and resulting load/deflection values are presented. The supporting structure consisted of two steel arch tubes, outer at edge of the membrane and inner supporting interior of the membrane roofing. The stability and strength behavior of the inner tube under both symmetrical and asymmetrical loading was monitored and is shown in some details. Second the SOFiSTiK software was employed to analyze the structural behavior in 3D, using geometrically nonlinear analysis with imperfections (GNIA. The numerical analysis, FE mesh sensitivity, the membrane prestressing and common boundary conditions are validated by test results. Finally a parametrical study concerning stability of mid arch with various geometries in a membrane structure with several supporting arches is presented, with recommendations for a practical design.

  13. 犬动脉瘤动物模型的血流动力学分析%Haemodynamic analysis in canine aneurysm model

    Institute of Scientific and Technical Information of China (English)

    李浩; 马勃; 李志强; 王启弘

    2015-01-01

    Objective To explore a way to establish a stable, ideal and handy intracranial aneurysm model for related studies. Methods Modified microsurgery technology was applied to establish sidewall, bifurcation, terminal and merged types of aneurysm (n=7 in each type). Two weeks after operation, color Doppler ultrasound, magnetic resonance imaging (MRI), magnetic resonance angiography (MRA) and intra-arterial digital subtraction angiography (IADSA) were performed and computational fluid dynamics (CFD) was used for simulation analysis of aneurysm models. Biomechanical properties of aneurysm wall tissues was analyzed by cell culture, then the above examinations were performed again after the aneurysm was embolized by micro coil (MC). Results All models were successfully established, and the MC embolization of aneurysm cavity achieved good efficacy. Vascular endothelial cells (VECs) proliferate well in vitro, and the VECs adhered to the sur⁃face of biodegradable polymeric materials successfully and grow into VEC layer structure. Hemodynamics analysis was per⁃formed in aneurysms model before and after embolization and relevant hemodynamic parameters was obtained. , Blood flow velocity are 2-7 cm/s in aneurysm and 8-26 cm/s in its parental artery. Conclusion A stable, ideal and handy intracranial aneurysm model was established and are essential in aneurysm related research.%目的:探讨建立稳定、理想、快捷的颅内动脉瘤模型的方法,为动脉瘤的相关研究提供可靠的动脉瘤模型。方法在改良的外科显微技术条件下制作侧壁型、分叉部、末端型和真性合并假性囊状动脉瘤,每种类型各7只。术后2周行彩色多普勒超声仪、磁共振成像(MRI)、磁共振血管成像(MRA)、数字减影动脉血管造影(IADSA)检查,进行动脉瘤模型的计算机流体力学(CFD)模拟分析。采用体外细胞培养的方法,对动脉瘤壁的组织生物力学特性进行分析,以微弹簧

  14. Reproducibility of haemodynamical simulations in a subject-specific stented aneurysm model--a report on the Virtual Intracranial Stenting Challenge 2007.

    Science.gov (United States)

    Radaelli, A G; Augsburger, L; Cebral, J R; Ohta, M; Rüfenacht, D A; Balossino, R; Benndorf, G; Hose, D R; Marzo, A; Metcalfe, R; Mortier, P; Mut, F; Reymond, P; Socci, L; Verhegghe, B; Frangi, A F

    2008-07-19

    This paper presents the results of the Virtual Intracranial Stenting Challenge (VISC) 2007, an international initiative whose aim was to establish the reproducibility of state-of-the-art haemodynamical simulation techniques in subject-specific stented models of intracranial aneurysms (IAs). IAs are pathological dilatations of the cerebral artery walls, which are associated with high mortality and morbidity rates due to subarachnoid haemorrhage following rupture. The deployment of a stent as flow diverter has recently been indicated as a promising treatment option, which has the potential to protect the aneurysm by reducing the action of haemodynamical forces and facilitating aneurysm thrombosis. The direct assessment of changes in aneurysm haemodynamics after stent deployment is hampered by limitations in existing imaging techniques and currently requires resorting to numerical simulations. Numerical simulations also have the potential to assist in the personalized selection of an optimal stent design prior to intervention. However, from the current literature it is difficult to assess the level of technological advancement and the reproducibility of haemodynamical predictions in stented patient-specific models. The VISC 2007 initiative engaged in the development of a multicentre-controlled benchmark to analyse differences induced by diverse grid generation and computational fluid dynamics (CFD) technologies. The challenge also represented an opportunity to provide a survey of available technologies currently adopted by international teams from both academic and industrial institutions for constructing computational models of stented aneurysms. The results demonstrate the ability of current strategies in consistently quantifying the performance of three commercial intracranial stents, and contribute to reinforce the confidence in haemodynamical simulation, thus taking a step forward towards the introduction of simulation tools to support diagnostics and

  15. Burmese Arched Harp

    Science.gov (United States)

    Williamson, Robert M.

    Our knowledge of the history, construction, and tunings of the Burmese arched harp (saùng gauk) comes from a variety of sources. Conversations with master harpists, together with recordings made of their performances between 1960 and 1980, provide richly detailed examples of the effect of Western music on a non-Western musical tradition. Scholars' essays and conference proceedings complement these first-hand accounts, expanding our understanding of Burmese music and musical instruments.

  16. How to Perfuse: Concepts of Cerebral Protection during Arch Replacement

    Directory of Open Access Journals (Sweden)

    Andreas Habertheuer

    2015-01-01

    Full Text Available Arch surgery remains undoubtedly among the most technically and strategically challenging endeavors in cardiovascular surgery. Surgical interventions of thoracic aneurysms involving the aortic arch require complete circulatory arrest in deep hypothermia (DHCA or elaborate cerebral perfusion strategies with varying degrees of hypothermia to achieve satisfactory protection of the brain from ischemic insults, that is, unilateral/bilateral antegrade cerebral perfusion (ACP and retrograde cerebral perfusion (RCP. Despite sophisticated and increasingly individualized surgical approaches for complex aortic pathologies, there remains a lack of consensus regarding the optimal method of cerebral protection and circulatory management during the time of arch exclusion. Many recent studies argue in favor of ACP with various degrees of hypothermic arrest during arch reconstruction and its advantages have been widely demonstrated. In fact ACP with more moderate degrees of hypothermia represents a paradigm shift in the cardiac surgery community and is widely adopted as an emergent strategy; however, many centers continue to report good results using other perfusion strategies. Amidst this important discussion we review currently available surgical strategies of cerebral protection management and compare the results of recent European multicenter and single-center data.

  17. The ARCHES Project

    Science.gov (United States)

    Motch, C.; Arches Consortium

    2015-09-01

    The Astronomical Resource Cross-matching for High Energy Studies (ARCHES) project is a FP7-Space funded programme started in 2013 and involving the Observatoire Astronomique de Strasbourg including the CDS (France), the Leibniz- Institut für Astrophysik Potsdam (Germany), the University of Leicester (UK), the Universidad de Cantabria (IFCA, Spain) and the Instituto Nacional de Tecnica Aeroespacial (Spain). ARCHES will provide the international astronomical community with well-characterised multi-wavelength data in the form of spectral energy distributions (SEDs) for large samples of objects extracted from the 3XMM X-ray catalogue of serendipitous sources. The project develops new tools implementing fully probabilistic simultaneous cross-correlation of several catalogues and a multi-wavelength finder for clusters of galaxies. SEDs are based on an enhanced version of the 3XMM catalogue and on a careful selection of the most relevant multi-wavelength archival catalogues. In order to ensure the largest audience, SEDs will be distributed to the international community through CDS services and through the Virtual Observatory. These enhanced resources are tested in the framework of several science cases. More information may be found at http://www.arches-fp7.eu/

  18. The Analysis of Domestic Oil Price Fluctuation Based on ARCH Models%基于ARCH类模型的国内油价波动分析

    Institute of Scientific and Technical Information of China (English)

    潘慧峰; 张金水

    2005-01-01

    The ARCH type models are applied on the weekly data of crude oil return from January 1997 to November 2003 to examine the features of volatility in China market. Our findings indicate that there exists significant conditional heteroskedasticity but with low persistence in the return of crude oil. The leverage effect in oil market is different from the one in the stock market, which shows that upward movements in the price of crude oil are followed by higher volatilities than downward movements of the same magnitude. Based on this, this paper analyzes the cause of the leverage effect in crude oil market from the angel of nonrenewable resources and discusses the countermeasures to deal with the volatility in oil price in terms of the situation of China.

  19. MR findings of thoracic and abdominal aortic aneurysms: comparison with angiographic and surgical findings

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yoong Ki; Kim, Tae Kyoung; Song, Jae Uoo; Kim, Seung Hoon; Lee, Han Kyung; Chung, Jin Wook; Park, Jae Hyung [College of Medicine, Seoul National University, Seoul (Korea, Republic of)

    1994-11-15

    To assess the utility of spin-echo magnetic resonance(MR) imaging in the evaluation of thoracic and abdominal aortic aneurysm. The spin-echo MR images of 27 aortic aneurysms in 22 patients were analyzed and correlated with angiography and/or operative findings retrospectively. Evaluations included location, type, and maximum diameter of the aneuyusm, mural thrombus, major branch involvement, and relationship with adjacent organ. The location of aneurysms was ascending thoracic aorta in seven cases, ascending thoracic aorta and aortic arch in one, descending thoracic aorta in six, thoracoabdominal aorta in three, and abdominal aorta in eight. Nineteen were fusiform, and eight were saccular. The mean of maximum diameters of the aneurysms was 7.9cm (4-10cm) on MR and 7.3cm (3-10cm) on angiography. Mural thrombus were noted in 13 cases on MR imaging and seven cases on angiography. Angiography also underestimated the amount of mural thrombus. Eight cases involved major aortic branches. Although MR imaging and angiography were equal in the assessment of major abdominal aortic branches, MR imaging could not clearly demonstrate arch vessels, especially left subclavian artery, in aortic arch aneurysms. Among seven ascending thoracic aneurysms, six had aortic regurgitation. MR imaging showed left ventricular enlargement in all six cases. There was pericardial effusion in four cases which were noted only on MR imaging. MR imaging demonstrated hydronephrosis and renal atrophy in two cases of abdominal aortic aneurysms respectively. In the assessment of size of the aneurysm, mural thrombus, and relation with adjacent organs, MR imaging was better than angiography. MR and angiographic findings were equal in the assessment of the location and type of the aneurysm. Angiography was better than MR imaging in the assessment of major branch involvement, especially left subclavian artery.

  20. Aortic Aneurysm Statistics

    Science.gov (United States)

    ... connective tissue disorders, such as Marfan syndrome and Ehlers-Danlos syndrome, get thoracic aortic aneurysms. Signs and symptoms of thoracic aortic aneurysm can include Sharp, sudden pain in the chest or upper back. Shortness of ...

  1. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... as atherosclerosis, high blood pressure, smokers, or a family history of abdominal aortic aneurysms. Today’s patient is ... be screened. In fact, patients who have a family history of aneurysm, men who are smoking over ...

  2. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... is actually an important factor. Most aneurysms we treat conservatively and we’ll just watch them. But ... has to be, and we generally don’t treat aneurysms until they get to be 5 to ...

  3. Cerebral Aneurysms Fact Sheet

    Science.gov (United States)

    ... cerebral aneurysm from forming. People with a diagnosed brain aneurysm should carefully control high blood pressure, stop smoking, and avoid cocaine use or other stimulant drugs. They should also ...

  4. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... to become you to our live webcast. Today we’re going to repair an abdominal aortic aneurysm ... and together as a team of multidisciplinary physicians, we’re going to repair an abdominal aortic aneurysm ...

  5. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... for the past three years, and his aneurysm has now grown to 5.4 centimeters. And this ... that in this particular patient that the aneurysm has reached the size where risk of rupture when ...

  6. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... atherosclerosis, high blood pressure, smokers, or a family history of abdominal aortic aneurysms. Today’s patient is a ... screened. In fact, patients who have a family history of aneurysm, men who are smoking over the ...

  7. Prognosis Predicting Score for Endovascular Treatment of Aneurysmal Subarachnoid Hemorrhage: A Risk Modeling Study for Individual Elderly Patients.

    Science.gov (United States)

    Duan, Guoli; Yang, Pengfei; Li, Qiang; Zuo, Qiao; Zhang, Lei; Hong, Bo; Xu, Yi; Zhao, Wenyuan; Liu, Jianmin; Huang, Qinghai

    2016-02-01

    The elderly patients with aneurysmal subarachnoid hemorrhage (aSAH) have a greater risk of poor clinical outcome after endovascular treatment (EVT) than younger patients do. Hence, it is necessary to explore which factors are associated with poor outcome and develop a predictive score specifically for elderly patients with aSAH receiving EVT. The aim of this study was to develop and validate a predictive score for 1-year outcomes in individual elderly patients with aSAH underwent EVT.In this 10-year prospective study, 520 consecutive aSAH elderly (age ≥ 60 years) patients underwent EVT in a single center were included. The risk factors, periprocedural, and 1-year follow-up data of all patients were entered in a specific prospective database. The modified Rankin scale was used for evaluating clinical outcome. To optimize the model's predictive capacity, the original matrix was randomly divided in 2 submatrices (learning and testing). The predictive score was developed using Arabic numerals for all variables based on the variable coefficients (β) of multivariable logistic regression analysis in the learning set and the predictive performance evaluation was assessed in the testing set. The risk classes were constructed using classification criteria based on sensitivity and specificity. The poor outcome rate at 1 year was 26.15%. Six risk factors, including age, hypertension, Hunt-Hess scale, Fisher scale, aneurysm location, and periprocedural complications, were independently associated with poor outcome and assembled the Changhai score. The discriminative power analysis with the area under the receiver operating characteristic curve (AUC) of the Changhai score was statistically significant (0.864, 0.824-0.904, P EVT. In combination with these risk factors, the Changhai score can be a useful tool in the prediction of clinical outcome but needs to be validated in various centers before it can be recommended for application. PMID:26886607

  8. Combined surgical and catheter-based treatment of extensive thoracic aortic aneurysm and aortic valve stenosis

    DEFF Research Database (Denmark)

    De Backer, Ole; Lönn, Lars; Søndergaard, Lars

    2015-01-01

    endovascular aneurysm repair (TEVAR) has changed and extended management options in thoracic aorta disease, including in those patients deemed unfit or unsuitable for open surgery. Accordingly, transcatheter aortic valve replacement (TAVR) is increasingly used to treat patients with symptomatic severe aortic......An extensive thoracic aortic aneurysm (TAA) is a potentially life-threatening condition and remains a technical challenge to surgeons. Over the past decade, repair of aortic arch aneurysms has been accomplished using both hybrid (open and endovascular) and totally endovascular techniques. Thoracic...

  9. Outcomes of single-stage total arch replacement via clamshell incision

    Directory of Open Access Journals (Sweden)

    Ishizaka Toru

    2011-09-01

    Full Text Available Abstract Background Treatment of complex aortic pathologies involving the transverse arch with extensive involvement of the descending aorta remains a surgical challenge. Since clamshell incision provides superior exposure of the entire thoracic aorta, we evaluated the use of this technique for single-stage total arch replacement by arch vessel reconstruction. Methods The arch-first technique combined with clamshell incision was used in 38 cases of aneurysm and aortic disease in 2008 and 2009. Extensive total arch replacement was used with clamshell incision for reconstruction of arch vessels under deep hypothermic circulatory arrest. Results Overall 30-day mortality was 13%. The mean operating time was approximately 8 hours. Deep hypothermia resulted in mean CPB time exceeding 4.5 hours and mean duration of circulatory arrest was 25 minutes. The overall postoperative temporary and permanent neurologic dysfunction rates were 3% and 3% for elective and 3% and 0% for emergency surgery, respectively. All patients except the five who died in hospital were discharged without nursing care after an average post-operative hospital stay of 35 days. Conclusions The arch-first technique, combined with clamshell incision, provides expeditious replacement of the thoracic aorta with an acceptable duration of hypothermic circulatory arrest and minimizes the risk of retrograde atheroembolism by using antegrade perfusion.

  10. Seismic behavior of concrete filled steel tubular arch structures

    Institute of Scientific and Technical Information of China (English)

    Xiong Feng; Sashi K Kunnath; Liu Haowu

    2005-01-01

    Shaking table tests of a 1:10 scale arch model performed to investigate the seismic behavior and resistance of concrete filled steel tubular (CFT) arch structures are described in this paper. The El-Centro record and Shanghai artificial wave were adopted as the input excitation. The entire test process can be divided into three stages depending on the lateral brace configurations, i.e., fully (five) braced, two braces removed, and all braces removed. A total of 46 tests, starting from the elastic state to failure condition, have been conducted. The natural vibration frequencies, responses of acceleration,displacement and strain were measured. From the test results, it is demonstrated that the CFT arch structures are capable of resisting severe ground motions and that CFT arches offer a credible alternative to reinforced concrete arches, especially in regions of high seismic intensity.

  11. Paediatric intracranial aneurysms

    Directory of Open Access Journals (Sweden)

    A A Wani

    2006-01-01

    Full Text Available Intracranial aneurysms in childhood account for 1-2% of intracranial aneurysms.[1],[2] These aneurysms have unique characteristics that make them different from those in adults. These differences are evident in their epidemiology, location, clinical spectrum, association with trauma and infection, complications and outcome.

  12. The ARCHES project

    CERN Document Server

    Motch, C; Genova, F; Esteban, F Jiménez-; López, M; Michel, L; Mingo, B; Mints, A; Gómez-Morán, A Nebot; Pineau, F -X; Rosen, S; Sanchez, E; Schwope, A; Solano, E; Watson, M

    2016-01-01

    ARCHES (Astronomical Resource Cross-matching for High Energy Studies) is a FP7-Space funded project whose aim is to provide the international astronomical community with well-characterised multi-wavelength data in the form of spectral energy distributions (SEDs) for large samples of objects extracted from the 3XMM DR5 X-ray catalogue of serendipitous sources. The project has developed new tools implementing fully probabilistic simultaneous cross-correlation of several catalogues for unresolved sources and a multi-wavelength finder for clusters of galaxies for extended sources. These enhanced resources have been tested in the framework of several science cases.

  13. Pediatric isolated bilateral iliac aneurysm.

    Science.gov (United States)

    Chithra, R; Sundar, R Ajai; Velladuraichi, B; Sritharan, N; Amalorpavanathan, J; Vidyasagaran, T

    2013-07-01

    Aneurysms are rare in children. Isolated iliac artery aneurysms are very rare, especially bilateral aneurysms. Pediatric aneurysms are usually secondary to connective tissue disorders, arteritis, or mycotic causes. We present a case of a 3-year-old child with bilateral idiopathic common iliac aneurysms that were successfully repaired with autogenous vein grafts.

  14. Aortic aneurysm and diverticulum of Kommerell: a dreadful concomitance

    Directory of Open Access Journals (Sweden)

    Fernando Peixoto Ferraz de Campos

    2012-12-01

    Full Text Available First described in 1936, the diverticulum of Kommerell (DOK is a dilatation of the proximal segment of an aberrant subclavian artery. Appearing more frequently in the left-sided aortic arch, the aberrant right subclavian artery passes behind the esophagus toward the right arm, causing symptoms in the minority of cases. Diagnosis is generally incidental with this pattern. When symptomatic, dysphagia, respiratory symptoms, hoarseness, chest pain, and upper limb ischemia are the most common complaints. Although debatable, the origin of DOK is accepted as being degenerative or congenital. The degenerative condition is normally associated with atherosclerosis and occurs more frequently after the age of 50 years with no gender predominance. Complications may be life threatening and are more commonly related to the diverticulum aneurysm or when associated with aortic diseases such as aneurysms or dissection. The authors present a case of a 67-year-old male with a history of acute chest pain, neurological disturbances, and hypertensive crisis. The diagnostic workup revealed an aortic arch aneurysm with intramural hematoma and a diverticulum aneurysm of Kommerell. Treatment was conservative at first. The patient presented a satisfactory outcome and was referred to an outpatient clinic for follow up and further therapeutic consolidation.

  15. Lipolysis of emulsion models of triglyceride-rich lipoproteins is altered in male patients with abdominal aorta aneurysm

    Directory of Open Access Journals (Sweden)

    J.J. Hosni

    2007-03-01

    Full Text Available Disorders of the lipid metabolism may play a role in the genesis of abdominal aorta aneurysm. The present study examined the intravascular catabolism of chylomicrons, the lipoproteins that carry the dietary lipids absorbed by the intestine in the circulation in patients with abdominal aorta aneurysm. Thirteen male patients (72 ± 5 years with abdominal aorta aneurysm with normal plasma lipid profile and 13 healthy male control subjects (73 ± 5 years participated in the study. The method of chylomicron-like emulsions was used to evaluate this metabolism. The emulsion labeled with 14C-cholesteryl oleate and ³H-triolein was injected intravenously in both groups. Blood samples were taken at regular intervals over 60 min to determine the decay curves. The fractional clearance rate (FCR of the radioactive labels was calculated by compartmental analysis. The FCR of the emulsion with ³H-triolein was smaller in the aortic aneurysm patients than in controls (0.025 ± 0.017 vs 0.039 ± 0.019 min-1; P < 0.05, but the FCR of14C-cholesteryl oleate of both groups did not differ. In conclusion, as indicated by the triglyceride FCR, chylomicron lipolysis is diminished in male patients with aortic aneurysm, whereas the remnant removal which is traced by the cholesteryl oleate FCR is not altered. The results suggest that defects in the chylomicron metabolism may represent a risk factor for development of abdominal aortic aneurysm.

  16. Basic flow structure in saccular aneurysms: a flow visualization study.

    Science.gov (United States)

    Steiger, H J; Poll, A; Liepsch, D; Reulen, H J

    1987-01-01

    Basic flow patterns were investigated in a set of glass aneurysm models by means of flow visualization methods. Dye injection and streaming double refraction were used to visualize flow. The circulation inside lateral aneurysms arising at a 90 degree angle from a straight parent conduit could not be visualized by the dye-injection technique but could be demonstrated by streaming double refraction. The inflow was seen to arise from the downstream lip of the orifice and to project to the dome of the aneurysm. Backflow to the parent conduit took place along the walls of the aneurysm. In aneurysms located at bifurcations, flow characteristics depended on the geometry of the bifurcation and the flow ratio between the branches. Relatively little intra-aneurysmal flow was demonstrated in side branch-related aneurysms arising distal to an asymmetric 90 degrees bifurcation of the type encountered at the junction of the internal carotid and posterior communicating arteries. Stagnation of flow at the neck and little intra-aneurysmal circulation were found with terminal aneurysms of the basilar bifurcation type if the outflow through the branches was symmetric. With asymmetric outflow, however, or if the axis of the aneurysm did not coincide with that of the afferent vessel, an active rotation developed in these aneurysms. The size of the aneurysm had no influence on the basic pattern of intra-aneurysmal circulation. The use of pulsatile perfusion did not significantly alter the basic flow patterns observed with steady flow. Locally disturbed laminar flow was observed in certain models at physiological Reynold's numbers, but there were no signs of fully developed turbulence.

  17. Interventional therapy of huge aneurysm

    International Nuclear Information System (INIS)

    Objective: To evaluate the methods and the efficacy of interventional therapy for huge aneurysm. Methods: Seven patients with huge aneurysm including 2 with pulmonary aneurysm, 2 with renal aneurysm, 1 with humeral artery aneurysm, 1 with right common iliac artery aneurysm, 1 with right internal iliac artery aneurysm. Among these, 5 were true aneurysm, and 2 were pseudoaneurysms caused by congenital, trauma, arteriosclerosis. Three patients were treated with endovascular covered stent graft and 2 patients with embolization containing metallic coils. Two patients were treated with partial aneurysm and feeding artery trunk embolization with metallic coils. Results: All 7 patients were successful carried out the interventional therapy with successful rate of 100%. Six aneurysms were completely obstructed with disappearance of symptoms and signs. One died of aneurysm rupture. No other complication occurred. Conclusion: Interventional therapy for huge aneurysm is an effective method. (authors)

  18. Brain Aneurysm Statistics and Facts

    Science.gov (United States)

    ... Statistics and Facts A- A A+ Brain Aneurysm Statistics and Facts An estimated 6 million people in ... Understanding the Brain Warning Signs/ Symptoms Brain Aneurysm Statistics and Facts Seeking Medical Attention Risk Factors Aneurysm ...

  19. Evaluation of the fit of preformed nickel titanium arch wires on normal occlusion dental arches

    OpenAIRE

    Al-Barakati, Rakhn G.; Nasser D. Alqahtani; Abdulaziz AlMadi; Sahar F. Albarakati; ALKofide, Eman A.

    2016-01-01

    Aim: To determine the fits of preformed nickel titanium (NiTi) archwires on dental arches with normal occlusion. Methods: Forty sets of upper and lower plaster models were obtained from men and women with Class I occlusions. Preformed 0.016″ × 0.022″ NiTi archwires from Rocky Mountain Orthodontics (RMO), 3 M Unitek, Ormco, and Dentaurum were evaluated in terms of their fits on dental arches from male, female, and combined cases. Data were analyzed by using fourth- and sixth-order polynomia...

  20. Splanchnic artery aneurysms

    Directory of Open Access Journals (Sweden)

    Davidović Lazar B.

    2006-01-01

    Full Text Available Introduction. Splanchnic artery aneurysms are uncommon but important vascular entity because nearly 25% of all cases present as surgical emergency. Objective. The purpose of our study was to present nine patients operated on at the Institute of cardiovascular diseases, as well as literature review of clinical presentation of the disease. Method. There were three splenic artery aneurysms, two celiac trunk aneurysms, and one aneurysm of the hepatic, superior mesenteric, inferior mesenteric and gastroduodenal artery. All patients were males, mean aged 67.5 years (60-73. In four patients, splanchnic artery aneurysm was discovered accidentally during routine ultrasonographic and angiographic examinations of the abdominal aorta. At that time, arteriovenous fistula was diagnosed in a patient No 1; it was formed after rupture of the splenic artery aneurysm into the splenic vein. Three aneurysms were manifested by abdominal pain and palpable pulsating abdominal mass. Two patients were admitted as urgent cases in the state of hemorrhagic shock and signs of intraabdominal bleeding due to rupture of the splenic and hepatic arteries. In 7 cases, diagnosis was made preoperatively by means of ultrasonography and angiography; in two patients, accurate diagnosis was confirmed during surgery. Results. Proximal and distal ligation of the artery was performed in a patient with rupture of the splenic aneurysm into the splenic vein that caused arteriovenous fistula. Gastroduodenal artery aneurysm was treated by trans-aneurysmatic ligation of its "entering" and "exiting" branches. Aneurysms of distal part of the superior mesenteric and splenic artery were resected without further reconstruction. Partial resection of the aneurysm and endoaneurysmorrhaphy was carried out in one case of celiac trunk aneurysm, and in another, after aneurysm resection, the restoration of blood flow through the hepatic and lienal artery was achieved by Dacron grafts. In a patient with the

  1. Micromanaging Abdominal Aortic Aneurysms

    Directory of Open Access Journals (Sweden)

    Lars Maegdefessel

    2013-07-01

    Full Text Available The contribution of abdominal aortic aneurysm (AAA disease to human morbidity and mortality has increased in the aging, industrialized world. In response, extraordinary efforts have been launched to determine the molecular and pathophysiological characteristics of the diseased aorta. This work aims to develop novel diagnostic and therapeutic strategies to limit AAA expansion and, ultimately, rupture. Contributions from multiple research groups have uncovered a complex transcriptional and post-transcriptional regulatory milieu, which is believed to be essential for maintaining aortic vascular homeostasis. Recently, novel small noncoding RNAs, called microRNAs, have been identified as important transcriptional and post-transcriptional inhibitors of gene expression. MicroRNAs are thought to “fine tune” the translational output of their target messenger RNAs (mRNAs by promoting mRNA degradation or inhibiting translation. With the discovery that microRNAs act as powerful regulators in the context of a wide variety of diseases, it is only logical that microRNAs be thoroughly explored as potential therapeutic entities. This current review summarizes interesting findings regarding the intriguing roles and benefits of microRNA expression modulation during AAA initiation and propagation. These studies utilize disease-relevant murine models, as well as human tissue from patients undergoing surgical aortic aneurysm repair. Furthermore, we critically examine future therapeutic strategies with regard to their clinical and translational feasibility.

  2. Alterations of blood flow pattern after triple stent endovascular treatment of saccular abdominal aortic aneurysm: a porcine model.

    Directory of Open Access Journals (Sweden)

    JAHIR RICHARD DE OLIVEIRA

    2016-06-01

    Full Text Available ABSTRACT Objective: to determine the blood flow pattern changes after endovascular treatment of saccular abdominal aortic aneurysm with triple stent. Methods: we conducted a hemodynamic study of seven Landrace and Large White pigs with saccular aneurysms of the infrarenal abdominal aorta artificially produced according to the technique described. The animals were subjected to triple stenting for endovascular aneurysm. We evaluated the pattern of blood flow by duplex scan before and after stent implantation. We used the non-paired Mann-Whitney test for statistical analysis. Results: there was a significant decrease in the average systolic velocity, from 127.4cm/s in the pre-stent period to 69.81cm/s in the post-stent phase. There was also change in the flow pattern from turbulent in the aneurysmal sac to laminate intra-stent. Conclusion: there were changes in the blood flow pattern of saccular abdominal aortic aneurysm after endovascular treatment with triple stent.

  3. Study on Simplified Model Construction Method of Dumbbell Shape Steel Pipe Concrete Arch Rib%哑铃形钢管混凝土拱肋简化建模方法研究

    Institute of Scientific and Technical Information of China (English)

    唐必刚; 张小华; 彭益华

    2012-01-01

    As the main stress component of steel pipe concrete arch bridge, whether the model construction method of dumbbell shape steel pipe concrete arch rib is reasonable is very significant to the structural safety of the whole bridge.By using MIDAS software, the arti- cle made various simplified simulation of the dumbbell shape steel pipe concrete arch db, and compared the calculations based on these simplified model with those based on the plates and solid element models constructed by using ANSYS software, so as to study and discuss simplified model construction methods which are more reasonable and more applicable.%哑铃形钢管混凝土拱肋作为钢管混凝土拱桥的主要受力构件,其建模方法是否合理对全桥结构的安全性具有重要的意义。文章采用MIDAS软件,对哑铃形钢管混凝土拱肋进行了多种简化模拟,并将这些简化模型计算结果与运用AN—SYS软件建立的板、实体单元模型的计算结果进行了比较,以研究探讨较为合理适用的简化建模方法。

  4. Nonstationary ARCH and GARCH with t-distributed Innovations

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Søndergaard; Rahbek, Anders

    Consistency and asymptotic normality are established for the maximum likelihood estimators in the nonstationary ARCH and GARCH models with general t-distributed innovations. The results hold for joint estimation of (G)ARCH effects and the degrees of freedom parameter parametrizing the t-distribut......Consistency and asymptotic normality are established for the maximum likelihood estimators in the nonstationary ARCH and GARCH models with general t-distributed innovations. The results hold for joint estimation of (G)ARCH effects and the degrees of freedom parameter parametrizing the t......-distribution. With T denoting sample size, classic square-root T-convergence is shown to hold with closed form expressions for the multivariate covariances....

  5. Simple Way of Recording Dental Arch Forms

    OpenAIRE

    Gupta, Shreya; Ratre, Ram Kishore; Jain, Sandhya; Chandki, Rita

    2015-01-01

    Like finger prints each individual has a unique dental arch form design. Recording patient’s dental arch form may be required in various fields in dentistry be it longitudinal studies for evaluating growth, forensic dentistry and most importantly in orthodontic practice for fabricating arch wires for individual patients. An easy and practical method to obtain individual arch form for each patient is explained.

  6. An Analytical Solution for Lateral Buckling Critical Load Calculation of Leaning-Type Arch Bridge

    Directory of Open Access Journals (Sweden)

    Ai-rong Liu

    2014-01-01

    Full Text Available An analytical solution for lateral buckling critical load of leaning-type arch bridge was presented in this paper. New tangential and radial buckling models of the transverse brace between the main and stable arch ribs are established. Based on the Ritz method, the analytical solution for lateral buckling critical load of the leaning-type arch bridge with different central angles of main arch ribs and leaning arch ribs under different boundary conditions is derived for the first time. Comparison between the analytical results and the FEM calculated results shows that the analytical solution presented in this paper is sufficiently accurate. The parametric analysis results show that the lateral buckling critical load of the arch bridge with fixed boundary conditions is about 1.14 to 1.16 times as large as that of the arch bridge with hinged boundary condition. The lateral buckling critical load increases by approximately 31.5% to 41.2% when stable arch ribs are added, and the critical load increases as the inclined angle of stable arch rib increases. The differences in the center angles of the main arch rib and the stable arch rib have little effect on the lateral buckling critical load.

  7. Pediatric cerebral artery aneurysms

    OpenAIRE

    Koroknay-Pál, PÀivi

    2012-01-01

    Objectives. Intracranial aneurysms in children are rare and population-based long-term follow-up studies are limited. In this study, a large clinical and angiographic long-term follow-up was carried out. The special characteristics of the patients and their aneurysms were assessed together with factors affecting early and long-term morbidity and mortality. Materials and Methods. All pediatric (≀18 years) aneurysm patients treated at the Department of Neurosurgery in Helsinki during 193...

  8. Mechanics of left ventricular aneurysm.

    Science.gov (United States)

    Radhakrishnan, S; Ghista, D N; Jayaraman, G

    1986-01-01

    When a coronary artery is significantly occluded, the left ventricular myocardial segment, which is perfused by that coronary artery, will become ischaemic and even irreversibly infarcted. An acute infarct has very low stiffness and if it involves the entire wall there is a risk of rupture; however, in the absence of such a critical situation, fibrous tissue is laid into the infarcted myocardial segment. Such an infarcted fibrotic myocardial segment will not be able to contract, and so generate tensile stress. The surrounding intact myocardium will contract and generate wall stress, thereby developing a high intra-chamber systolic pressure; the chronically infarcted and fibrotic segment will have to sustain this high chamber pressure. Its loss of contractility and the resulting reduced systolic stiffness relative to the intact segment, will cause it to deform into a bulge; this is an aneurysm. When a left ventricular chamber with an aneurysm contracts during the systolic phase, some blood also goes into the aneurysm, and this decreases the stroke volume; since the aneurysm wall is passive, stagnant blood flow prevails in the aneurysm itself, which in turn can give rise to the formation of a mural thrombus. These serious consequences provide a justification for the analysis of an infarcted left ventricular chamber, in order to predict the size of the aneurysmic bulge. Such an analysis is presented in this paper. To determine the left ventricular wall deformation, and the stress arising from infarction of a wall segment (which leads to a ventricular aneurysm) the left ventricle is modelled here as a pressurized ellipsoidal shell. Deformations of infarcted wall segments are computed for several damaged wall-thicknesses in left ventricles of different shapes. The analysis involves a derivation of equations for wall-stress equilibrium with the chamber pressure, and myocardial incompressibility before and after infarct formation. The equations are solved by the Newton

  9. Screening for aortic aneurysm after treatment of coarctation.

    Science.gov (United States)

    Hoffman, James L; Gray, Robert G; LuAnn Minich, L; Wilkinson, Stephen E; Heywood, Mason; Edwards, Reggie; Weng, Hsin Ti; Su, Jason T

    2014-01-01

    Isolated coarctation of the aorta (CoA) occurs in 6-8 % of patients with congenital heart disease. After successful relief of obstruction, patients remain at risk for aortic aneurysm formation at the site of the repair. We sought to determine the diagnostic utility of echocardiography compared with advanced arch imaging (AAI) in diagnosing aortic aneurysms in pediatric patients after CoA repair. The Congenital Heart Databases from 1996 and 2009 were reviewed. All patients treated for CoA who had AAI defined by cardiac magnetic resonance imaging (MRI), computed tomography (CT), or catheterization were identified. Data collected included the following: type, timing, and number of interventions, presence and time to aneurysm diagnosis, and mortality. Patients were subdivided into surgical and catheterization groups for analysis. Seven hundred and fifty-nine patients underwent treatment for CoA during the study period. Three hundred and ninety-nine patients had at least one AAI. Aneurysms were diagnosed by AAI in 28 of 399 patients at a mean of 10 ± 8.4 years after treatment. Echocardiography reports were available for 380 of 399 patients with AAI. The sensitivity of echocardiography for detecting aneurysms was 24 %. The prevalence of aneurysms was significantly greater in the catheterization group (p Aneurysm was also diagnosed earlier in the catheterization group compared with the surgery group (p = 0.02). Multivariate analysis showed a significantly increased risk of aneurysm diagnosis in patients in the catheterization subgroup and in patients requiring more than three procedures. Aortic aneurysms continue to be an important complication after CoA repair. Although serial echocardiograms are the test of choice for following-up most congenital cardiac lesions in pediatrics, our data show that echocardiography is inadequate for the detection of aneurysms after CoA repair. Because the time to aneurysm diagnosis was shorter and the risk greater in the

  10. Cephalic vein aneurysm.

    Science.gov (United States)

    Faraj, Walid; Selmo, Francesca; Hindi, Mia; Haddad, Fadi; Khalil, Ismail

    2007-11-01

    Cephalic vein aneurysms are rare malformations that may develop in any part of the vascular system, and their history, presentation, and management vary depending on their site. The etiology of venous aneurysms remains unclear, although several theories have been elaborated. Venous aneurysms are unusual vascular malformations that occur equally between the sexes and are seen at any age; they can present as either a painful or a painless subcutaneous mass. No serious complications have been reported from upper extremity venous aneurysms. Surgical excision is the definitive management for most of these. The case reported here presented with a painless and mobile, soft, subcutaneous mass that caused only cosmetic concern.

  11. Tissue Responses to Stent Grafts with Endo-Exo-Skeleton for Saccular Abdominal Aortic Aneurysms in a Canine Model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Il Young; Chung, Jin Wook; Kim, Hyo Cheol [Dept. of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Clinical Research Institute, Seoul (Korea, Republic of); Choi, Young Ho; So Young Ho [Dept. of Radiology, Seoul National University Boramae Hospital, Seoul (Korea, Republic of); Kim, Hyun Beom [Dept. of Radiology, National Cancer Center, Goyang (Korea, Republic of); Min, Seung Kee [Dept. of Surgery, Seoul National University College of Medicine, Seoul (Korea, Republic of); Park, Jae Hyung [Dept. of Radiology, Gachon University Gil Medical Center, Incheon (Korea, Republic of)

    2014-10-15

    We evaluated the effect of close contact between the stent and the graft on the induction of endothelial covering on the stent graft placed over an aneurysm. Saccular abdominal aortic aneurysms were made with Dacron patch in eight dogs. The stent graft consisted of an inner stent, a expanded polytetrafluoroethylene graft, and an outer stent. After sacrificing the animals, the aortas with an embedded stent graft were excised. The aortas were inspected grossly and evaluated microscopically. The animals were sacrificed at two (n = 3), six (n = 3), and eight months (n = 2) after endovascular repair. In two dogs, the aortic lumen was occluded at two months after the placement. On gross inspection of specimens from the other six dogs with a patent aortic lumen, stent grafts placed over the normal aortic wall were covered by glossy white neointima, whereas, stent grafts placed over the aneurysmal aortic wall were covered by brownish neointima. On microscopic inspection, stent grafts placed over the normal aortic wall were covered by thin neointima (0.27 ± 0.05 mm, mean ± standard deviation) with an endothelial layer, and stent grafts placed over the aneurysmal aortic wall were covered by thick neointima (0.62 ± 0.17 mm) without any endothelial lining. Transgraft cell migration at the normal aortic wall was more active than that at the aneurysmal aortic wall. Close contact between the stent and the graft, which was achieved with stent grafts with endo-exo-skeleton, could not enhance endothelial covering on the stent graft placed over the aneurysms.

  12. Computational analysis of anterior communicating artery aneurysm shear stress before and after aneurysm formation

    Science.gov (United States)

    Castro, Marcelo A.; Putman, Christopher M.; Cebral, Juan R.

    2011-12-01

    It is widely accepted that complexity in the flow pattern at the anterior communicating artery (AComA) is associated with the high rate of aneurysm formation at that location observed in large studies. The purpose of this work is to study associations between hemodynamic patterns, and AComA aneurysm initiation by comparing hemodynamics in the aneurysm and the normal model where the aneurysm was computationally removed. Vascular models of both right and left circulation were independently reconstructed from three-dimensional rotational angiography images using deformable models after image registration of both images, and fused using a surface merging algorithm. The geometric models were then used to generate high-quality volumetric finite element grids of tetrahedra with an advancing front technique. For each patient, the second anatomical model was created by digitally removing the aneurysm. It was iteratively achieved by applying a Laplacian smoothing filter and remeshing the surface. Finite element blood flow numerical simulations were performed for both the pathological and normal models under the same personalized pulsatile flow conditions imposed at the inlets of both models. The Navier-Stokes equations were numerically integrated by using a finite-element formulation. It was observed that aneurysms initiated in regions of high and moderate WSS in the counterpart normal models. Adjacent or close to those regions, low WSS portions of the arterial wall were not affected by the disease. These results are in line with previous observations at other vascular locations.

  13. Intraorbital ophthalmic artery aneurysm associated with basilar tip saccular aneurysm

    Energy Technology Data Exchange (ETDEWEB)

    Dehdashti, A.R.; Tribolet, N. de [Department of Neurosurgery, HUG, Geneva (Switzerland); Safran, A.B. [Department of Ophthalmology, HUG, Geneva (Switzerland); Martin, J.B.; Ruefenacht, D.A. [Division of Neuroradiology, HUG, Geneva (Switzerland)

    2002-07-01

    We present a rare case of intraorbital ophthalmic artery aneurysm found incidentally, together with a ruptured aneurysm of the tip of the basilar artery. The intraorbital aneurysm was asymptomatic, and no treatment was offered. Angiographic control was recommended to detect any progression. Treatment may be indicated for documented enlargement or significant mass effect of the aneurysm. (orig.)

  14. Intraorbital ophthalmic artery aneurysm associated with basilar tip saccular aneurysm

    International Nuclear Information System (INIS)

    We present a rare case of intraorbital ophthalmic artery aneurysm found incidentally, together with a ruptured aneurysm of the tip of the basilar artery. The intraorbital aneurysm was asymptomatic, and no treatment was offered. Angiographic control was recommended to detect any progression. Treatment may be indicated for documented enlargement or significant mass effect of the aneurysm. (orig.)

  15. Computer Simulations of Pulsatile Human Blood Flow Through 3D-Models of the Human Aortic Arch, Vessels of Simple Geometry and a Bifurcated Artery: Investigation of Blood Viscosity and Turbulent Effects

    CERN Document Server

    Sultanov, Renat A

    2008-01-01

    We report computational results of blood flow through a model of the human aortic arch and a vessel of actual diameter and length. On the top of the aortic arch the branching of the %%three arteries are included: the subclavian and jugular. A realistic pulsatile flow is used in all simulations. Calculations for bifurcation type vessels are also carried out and presented. Different mathematical methods for numerical solution of the fluid dynamics equations have been considered. The non-Newtonian behaviour of the human blood is investigated together with turbulence effects. A detailed time-dependent mathematical convergence test has been carried out. The results of computer simulations of the blood flow in vessels of three different geometries are presented: for pressure, strain rate and velocity component distributions we found significant disagreements between our results obtained with realistic non-Newtonian treatment of human blood and the widely used method in the literature: a simple Newtonian approximati...

  16. ARCH Effect in Classical Market-Timing Models with Lagged Market Variable: the Case of Polish Market

    OpenAIRE

    Joanna Olbrys

    2011-01-01

    The main goal of this study is to present the regressions of the GARCH versions of classical market-timing models of Polish equity funds. We examine the models with lagged values of the market factor as an additional variable because of the Fisher’s effect in the case of the main Warsaw Stock Exchange indexes. The market-timing and selectivity abilities of fund managers are evaluated for the period Jan 2003 – June 2011. Results on both the HAC and the GARCH estimates are qualitatively similar...

  17. Location and Incidence Rate of Anastomotic Aneurysms – own Clinical Material and Literature Review

    Directory of Open Access Journals (Sweden)

    Pogorzelski Ryszard

    2014-04-01

    Full Text Available Anastomotic aneurysms occurs at various levels of arterial system. Determining their location and incidence rate required investigation of large patient clinical material. Material and methods. In the years 1989-2010 in local centre 230 anastomotic aneurysms were operated in 180 patients. Results. For 187 (81.3% patients anastomotic aneurysms were localised in the groin, while for remaining 43 (18.7% they occurred in other localisations. In aortic arch branch they occurred four times (1.7, in descending aorta - three times (1.3%, in abdominal aorta - 14 (6.1% and in iliac arteries - 6 (2.6%. While for anastomosis with popliteal artery they were diagnosed in 16 (7% patients. Own clinical material was compared with literature data. Conclusions. Anastomotic aneurysms in over 80% of cases occur in the groin, remaining percentage corresponds to other localisations.

  18. The Foot’s Arch and the Energetics of Human Locomotion

    Science.gov (United States)

    Stearne, Sarah M.; McDonald, Kirsty A.; Alderson, Jacqueline A.; North, Ian; Oxnard, Charles E.; Rubenson, Jonas

    2016-01-01

    The energy-sparing spring theory of the foot’s arch has become central to interpretations of the foot’s mechanical function and evolution. Using a novel insole technique that restricted compression of the foot’s longitudinal arch, this study provides the first direct evidence that arch compression/recoil during locomotion contributes to lowering energy cost. Restricting arch compression near maximally (~80%) during moderate-speed (2.7 ms−1) level running increased metabolic cost by + 6.0% (p < 0.001, d = 0.67; unaffected by foot strike technique). A simple model shows that the metabolic energy saved by the arch is largely explained by the passive-elastic work it supplies that would otherwise be done by active muscle. Both experimental and model data confirm that it is the end-range of arch compression that dictates the energy-saving role of the arch. Restricting arch compression had no effect on the cost of walking or incline running (3°), commensurate with the smaller role of passive-elastic mechanics in these gaits. These findings substantiate the elastic energy-saving role of the longitudinal arch during running, and suggest that arch supports used in some footwear and orthotics may increase the cost of running. PMID:26783259

  19. Laparo- and thoracoscopic aortic aneurysm neck optimization and treatment of potential endoleaks type IA and II in a porcine model

    DEFF Research Database (Denmark)

    Kloster, Brian Ozeraitis; Lund, Lars; Lindholt, Jes S.

    2016-01-01

    Background: Endovascular repair of aortic aneurysms has a higher incidence of late complications, and open conversion (OC) associated with high mortality may be required. As alternatives to OCs, we propose minimal invasive laparo-/thoracoscopic approaches, either to control endoleaks after endova...

  20. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... screened. In fact, patients who have a family history of aneurysm, men who are smoking over the age of 55 should be screened for aneurysms. And the way to screen is with a simple ultrasound. But sometimes a ...

  1. Atherosclerotic femoral artery aneurysms

    DEFF Research Database (Denmark)

    Levi-Mazloum, Niels Donald; Schroeder, T V

    1996-01-01

    Based on a clinical suspicion of an increase in the proportion of deep femoral aneurysms, we reviewed the case records of patients who underwent reconstructive procedures for femoral aneurysms to investigate if this could be confirmed and explained by selection of patient or modality of diagnosis...

  2. Hemodynamic effects of stenting on wide-necked intracranial aneurysms

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-sen; LUO Bin; LI Chuan-hui; YANG Xin-jian; WANG Sheng-zhang; QIAO Ai-ke; CHEN Jia-liang; ZHANG Kun-ya; LIU Zhi-cheng; ZHAO Yu-jing; ZHANG Ying

    2010-01-01

    Background Stent placement has been widely used to assist coiling in cerebral aneurysm treatments. The present study aimed to investigate the hemodynamic effects of stenting on wide-necked intracranial aneurysms.Methods Three idealized plexiglass aneudsmal models with different geometries before and after stenting were created, and their three-dimensional computational models were constructed. Flow dynamics in stented and unstented aneurismal models were studied using in vitro flow visualization and computational fluid dynamics (CFD) simulations. In addition, effects of stenting on flow dynamics in a patient-specific aneurysm model were also analyzed by CFD.Results The results of flow visualization were consistent with those obtained with CFD simulations. Stent deployment reduced vortex inside the aneurysm and its impact on the aneurysm sac, and decreased wall shear stress on the sac.Different aneurysm geometries dictated fundamentally different hemodynamic patterns and outcomes of stenting.Conclusions Stenting across the neck of aneurysms improves local blood flow profiles. This may facilitate thrombus formation in aneurysms and decrease the chance of recanalization.

  3. Morphological and Biomechanical Differences in the Elastase and AngII apoE−/− Rodent Models of Abdominal Aortic Aneurysms

    Directory of Open Access Journals (Sweden)

    Evan H. Phillips

    2015-01-01

    Full Text Available An abdominal aortic aneurysm (AAA is a potentially fatal cardiovascular disease with multifactorial development and progression. Two preclinical models of the disease (elastase perfusion and angiotensin II infusion in apolipoprotein-E-deficient animals have been developed to study the disease during its initiation and progression. To date, most studies have used ex vivo methods to examine disease characteristics such as expanded aortic diameter or analytic methods to look at circulating biomarkers. Herein, we provide evidence from in vivo ultrasound studies of the temporal changes occurring in biomechanical parameters and macromolecules of the aortic wall in each model. We present findings from 28-day studies in elastase-perfused rats and AngII apoE−/− mice. While each model develops AAAs specific to their induction method, they both share characteristics with human aneurysms, such as marked changes in vessel strain and blood flow velocity. Histology and nonlinear microscopy confirmed that both elastin and collagen, both important extracellular matrix molecules, are similarly affected in their levels and spatial distribution. Future studies could make use of the differences between these models in order to investigate mechanisms of disease progression or evaluate potential AAA treatments.

  4. Mechanics Evolution Characteristics Analysis of Pressure-arch in Fully-mechanized Mining Field

    Directory of Open Access Journals (Sweden)

    S.R. Wang

    2014-09-01

    Full Text Available Based on a practical engineering, the three-dimension computational model was built using FLAC3D under the fullymechanized mining condition. Considering four variation factors, such as the distance of mining advancing, the strength of the surrounding rock, the speed of mining advancing and the dip angle of the coal seam, the mechanics evolution characteristics of the pressure-arch were analyzed. The result showed that for the horizontal seam, the geometric shape of the pressure-arch varied from flat arch to round arch gradually and the height and thickness of the pressure-arch also increased; the maximum principal stress in the skewback also increased with the working face advancing. With the strength of the surrounding rock from soft to hard, the arch thickness reduced, and the arch loading decreased. To improve the mining speed can do some contributions to the stability of the pressure-arch in the mining field. With the increase of dip angle of the seam, the pressure-arch displayed an asymmetric shape, the vault was tilted and moved to the upward direction. At the same time, the thickness of the pressure-arch increased, and the stress concentration in the skewback tended to be further intensified.

  5. Aneurismas da aorta Aortic aneurysms

    Directory of Open Access Journals (Sweden)

    Januário M Souza

    1992-09-01

    Full Text Available Entre janeiro de 1979 e janeiro de 1992, foram realizadas 212 operações para correção de aneurismas e de dissecções da aorta. Neste trabalho serão analisados 104 procedimentos cirúrgicos (em 97 pacientes para correção de aneurismas. A idade dos pacientes variou de 14 a 79 anos (média 59,5 anos e o sexo predominante foi o masculino, com 75 pacientes. Os aneurismas localizavam-se na aorta ascendente em 46 pacientes, na croça em 8, na aorta descendente em 8, na aorta toráco-abdominal em 8, na aorta abdominal em 21, na aorta descendente e abdominal em 2, na aorta ascendente e tóraco-abdominal em 2, na aorta ascendente e descendente em 1, na aorta ascendente, croça e descendente em 1. Doenças cardiovasculares associadas estavam presentes em 39 pacientes, sendo valvopatia aórtica em 18 (excluídos os pacientes com ectasiaânulo-aórtíca, insuficiência coronária em 17, coarctação da aorta em 2, persistência do canal arterial em 1 e valvopatia mitral e aórtica em 1. A mortalidade imediata (hospitalar e/ou 30 dias foi de 14,4%, sendo de 27,7% (5/18 para pacientes com mais de 70 anos e de 11,3% (9/79 para pacientes com idade inferior a 70 anos. Os aneurismas localizados na aorta ascendente e croça foram operados como o auxílio de circulação extracorpórea. Parada circulatória e hipotermia profunda foram utilizadas em todos os pacientes com aneurisma da croça. O estudo tomográfico e angiográfico deve ser de toda a aorta, pela possibilidade de aneurismas de localizações múltiplas.Among 212 patients undergoing operation for aortic aneurysm and aortic dissection between January 1979 and January 1992, 97 were operated on for aneurysms. The aneurysms were localized in: ascending aorta in 46 patients, transverse aortic arch in 8, descending aorta in 8, thoracoabdominal aorta in 8, abdominal (infrarenal aorta in 21, descending and abdominal aorta in 2, ascending and thoracoabdominal aorta in 2, ascending and descending in 1

  6. Impact of aneurysmal geometry on intraaneurysmal flow: a computerized flow simulation study

    International Nuclear Information System (INIS)

    This study was performed to assess the effect of aneurysm geometry on parameters that may have an impact on the natural history of intracranial aneurysms, such as intraaneurysmal flow pressure and shear stress. Flow was simulated in 21 randomly selected aneurysms using finite volume modeling. Ten aneurysms were classified as side-wall aneurysms, with either single-sided or circumferential involvement of the parent artery wall, and 11 as bifurcation aneurysms (symmetric or asymmetric), with an axis either perpendicular or parallel to the parent artery. The flow patterns were classified as either jet or vortex types (with regular or irregular vortex flow). Pressures and shear stresses were characterized as evenly or unevenly distributed over the aneurysm wall and neck. All side-wall and four of the bifurcation aneurysms with a perpendicular axis had a vortex type flow pattern and seven bifurcation aneurysms with a parallel axis (four symmetric and two asymmetric) had a jet flow pattern. Jet type flow was associated with an uneven pressure distribution in seven out of seven aneurysms. Vortex type flow resulted in an even pressure distribution in five out of six aneurysms with an irregular flow pattern and six out of eight with a regular flow pattern. No firm relationship could be established between any geometrical type and shear stress distribution. Only 1 of 14 aneurysms with a perpendicular axis, but 4 of 7 aneurysms with a parallel axis, had ruptured. Aneurysm geometry does have an impact on flow conditions. Aneurysms with a main axis parallel to the parent artery have a tendency to have a jet flow pattern and uneven distribution of unsteady pressure. These aneurysms may have a higher rate of rupture as than those with a main axis perpendicular to the parent artery. (orig.)

  7. MACROSCOPIC SOIL ARCH SHAPE AND EVOLUTION MODEL OF SAND FILLING PILED EMBANKMENT%砂填料桩承式路堤宏观土拱形态与演化模型

    Institute of Scientific and Technical Information of China (English)

    芮瑞; 胡港; 夏元友; 黄成

    2014-01-01

    At present,there are few studies of applicable conditions of models and evolution laws of soil arching effect. To solve this issue,a new plane strain model test apparatus is developed to discover macroscopic soil arch shape under different pile spacings and the evolution process of soil arching during the settlement of soil between the piles. Soil and piles are simplified into removable plates and rigid plates,and the pile-soil interaction is simplified into relative settlement on the pile top,which could be simulated by moving the removable plates in a precise way. Photographic survey is applied to the model test. Every 0.02 mm when the plates settle,a photo is taken. Then whole field displacements of the embankment can be measured by tracing the particles. Nine groups of piled embankment model tests with 3 different filling heights and 3 different pile spacings are carried out with the new apparatus. A couple of symmetrical triangular sliding surfaces appear initially in all the 9 tests,which is called initial triangular arch model. Following two different evolution modes for the initial triangular arch model will be revealed with further moving the removable plates:in the case of H/(s-a)<1.8,the initial triangular arch model will turn to be triangular multi-arch model with the increased settlement of soil between piles;in the other case of H/(s-a)≥1.8,the initial triangular arch model will evolve into pagoda-shaped multi-arch model with the increased settlement of soil between piles. Key parameters of different stages of the models are summarized,which will provide reference for the next mechanical analysis in soil arching development condition.%基于目前研究很少关注土拱效应模型的适用条件和演化规律的现状,采用自制平面应变模型对砂填料桩承式路堤在不同桩间距下的宏观土拱形态,以及宏观土拱在桩间土下移过程中可能出现的演化现象进行探讨。模型试验将桩与土相互作用简

  8. [Splenic artery aneurysms].

    Science.gov (United States)

    Colović, R; Davidović, L; Bilanović, D; Krivokapić, Z; Grubor, N; Cvetković, S; Radak, V; Marković, M

    2006-01-01

    Although the third most frequent aneurysm in the abdomen, after aneurysms of the aorta and iliac arteries, and most frequent aneurisms of visceral arteries, splenic artery aneurysms are rare, but not very rare. Thanks to the new imaging techniques, first of all ultrasonography, they have been discovered with increasing frequency. We present a series of 9 splenic artery aneurysms. Seven patients were female and two male of average age 49 years (ranging from 28 to 75 years). The majority of afected women were multiparae, with average 3 children (ranging from 1 to 6). One patient had a subacute rupture, and 2 had ruptures into the splenic vein causing portal hypertension. The spleen was enlarged in 7 out of 9 patients. The average size of aneurysms was 3,2 cm (ranging from 2 to 8 cm). The preoperative diagnosis of splenic artery aneurysm was established in 6 patients while in 3 patients aneurism was accidentally found during other operations, during splenectomy in 2, and during the excision of a retroperitoneal tumour in 1 patient. Aneurysmectomy was carried out in 7 patients, while a ligation of the incoming and outcoming wessels was performed in 2 patients with arteriovenous fistula. Splenectomy was performed in 6 patients, while pancreatic tail resection, cholecystectomy and excision of the retroperitoneal tumor were performed in 3 patients. Additional resection of the abdominal aortic aneurysm with reconstruction of aortoiliac segment was performed in 2 patients. There were no mortality and the postoperative recovery was uneventful in all patients. PMID:16989145

  9. 应用LOM法制作-下颌骨及牙列的三维实体模型%3D Solid Model of Mandible with Dental Arch via LOM Method

    Institute of Scientific and Technical Information of China (English)

    张睿; 李玲; 于力牛; 白瑞军; 张富强; 王成焘; 徐肖云

    2000-01-01

    Objective Based on 3D reconstruction data from CT scaning, a solid model of mandible with dental arch is ob tained via a rapid prototype machine using LOM method. Method 3D reconstruction data is transferred to STL file using software of Delcam(UK) , which will be fed to Magics RP software for detection and rebuilding. Reproduction of the papery model of mandible with dental arch is then performed with highly geometric sunilarity. Result The RP model of mandible with dental arch is obtained. Conclusion Accuracy of the reproduction model meets the demands of studies in prosthetic dentist, which gives the possibility of computer aided design of prosthetic dentistry based on 3D solid model.%采用基于CT断层影像的下颌骨及牙列三维重建数据,利用快速成型中的分层制造方法复制下颌骨 及牙列。方法利用Delcam公司(UK)软件将下颌骨及牙列三维重建的数据文件转换为STL文件,采用Magics RP 软件读入STL文件并进行检验与修补。制作下颌骨及牙列纸质实物模型,与下颌骨及牙列标本模型的几何相似性 良好。结果得到了下颌骨及下牙列的快速原型模型。结论下颌骨及牙列复制模型精度符合口腔修复中的要 求,可在其计算机三维实体模型基础上进行牙列缺损的计算机辅助修复设计。

  10. Patient-Specific Simulation Models of the Abdominal Aorta With and Without Aneurysms

    DEFF Research Database (Denmark)

    Enevoldsen, Marie Sand

    . The collagen fibers are grouped in four directions of orientation. The purpose of the first study was to investigate whether significant risk factors related to AAA development can be identified from a specific pattern in the material parameters of the 4FF model. Smoking is a leading self-inflicted risk factor...... incorporating subject-specific geometry of the abdominal aorta (AA) as well as subject-specific blood flow conditions. The geometry was acquired from magnetic resonance imaging, and the blood flow characteristics were acquired from ultrasound. The solid AA wall was modeled as a thick-walled cylinder allowing...... the predictability of the 4FF model. This was achieved by combining subject-specific blood flow and age-matched material parameters of the 4FF model in a fluid-structure interaction (FSI) model. The predicted wall dynamics were compared to in vivo wall dynamics obtained with ultrasound. Simulation results indicate...

  11. Theory of Arched Structures Strength, Stability, Vibration

    CERN Document Server

    Karnovsky, Igor A

    2012-01-01

    Theory of Arched Structures: Strength, Stability, Vibration presents detailed procedures for analytical analysis of the strength, stability, and vibration of arched structures of different types, using exact analytical methods of classical structural analysis. The material discussed is divided into four parts. Part I covers stress and strain with a particular emphasis on analysis; Part II discusses stability and gives an in-depth analysis of elastic stability of arches and the role that matrix methods play in the stability of the arches; Part III presents a comprehensive tutorial on dynamics and free vibration of arches, and forced vibration of arches; and Part IV offers a section on special topics which contains a unique discussion of plastic analysis of arches and the optimal design of arches.

  12. Pediatric cerebral aneurysms.

    Science.gov (United States)

    Gemmete, Joseph J; Toma, Ahmed K; Davagnanam, Indran; Robertson, Fergus; Brew, Stefan

    2013-11-01

    Childhood intracranial aneurysms differ from those in the adult population in incidence and gender prevalence, cause, location, and clinical presentation. Endovascular treatment of pediatric aneurysms is the suggested approach because it offers both reconstructive and deconstructive techniques and a better clinical outcome compared with surgery; however, the long-term durability of endovascular treatment is still questionable, therefore long-term clinical and imaging follow-up is necessary. The clinical presentation, diagnosis, and treatment of intracranial aneurysms in children are discussed, and data from endovascular treatments are presented.

  13. Thoracic type Ia endoleak: direct percutaneous coil embolization of the aortic arch at the blood entry site after TEVAR and double-chimney stent-grafts

    International Nuclear Information System (INIS)

    To introduce a novel percutaneous technique to stop blood entry at the lesser aortic arch curvature by coil embolisation in type Ia endoleak after TEVAR. A 61-year-old Marfan patient presented with type Ia endoleak of the aortic arch and a growing aortic arch pseudoaneurysm after TEVAR. Multiple preceding operations and interventions made an endovascular approach unsuccessful. Direct percutaneous puncture of the aneurysmal sac would have cured the sign, but not the cause of blood entry at the lesser curvature of the aortic arch. Direct CT-guided percutaneous puncture of the blood entry site in the aortic arch with fluoroscopically guided coil embolisation using detachable extra-long coils was successfully performed. Three weeks after the intervention, the patient developed fever because of superinfection of the pseudoaneurysm. The blood cultures and CT-guided mediastinal aspirate were sterile. After intravenous administration of antibiotics, the fever disappeared and the patient recovered. Six-month follow-up showed permanent closure of the endoleak and a shrinking aneurysmal sac. Direct percutaneous puncture of the aortic arch at the blood entry site of a thoracic type Ia endoleak after TEVAR and double-chimney stent-grafts with coil embolisation of the wedge-shaped space between the lesser aortic curvature and the stent-graft is possible. (orig.)

  14. Thoracic type Ia endoleak: direct percutaneous coil embolization of the aortic arch at the blood entry site after TEVAR and double-chimney stent-grafts

    Energy Technology Data Exchange (ETDEWEB)

    Bangard, Christopher; Franke, Mareike; Maintz, David; Chang, De-Hua [University Hospital, University of Cologne, Department of Radiology, Cologne (Germany); Pfister, Roman [University Hospital, University of Cologne, Department of Internal Medicine III, Cologne (Germany); Deppe, Antje-Christin [University Hospital, University of Cologne, Department of Cardiothoracic Surgery, Cologne (Germany); Matoussevitch, Vladimir [University Hospital, University of Cologne, Department of Vascular Surgery, Cologne (Germany)

    2014-06-15

    To introduce a novel percutaneous technique to stop blood entry at the lesser aortic arch curvature by coil embolisation in type Ia endoleak after TEVAR. A 61-year-old Marfan patient presented with type Ia endoleak of the aortic arch and a growing aortic arch pseudoaneurysm after TEVAR. Multiple preceding operations and interventions made an endovascular approach unsuccessful. Direct percutaneous puncture of the aneurysmal sac would have cured the sign, but not the cause of blood entry at the lesser curvature of the aortic arch. Direct CT-guided percutaneous puncture of the blood entry site in the aortic arch with fluoroscopically guided coil embolisation using detachable extra-long coils was successfully performed. Three weeks after the intervention, the patient developed fever because of superinfection of the pseudoaneurysm. The blood cultures and CT-guided mediastinal aspirate were sterile. After intravenous administration of antibiotics, the fever disappeared and the patient recovered. Six-month follow-up showed permanent closure of the endoleak and a shrinking aneurysmal sac. Direct percutaneous puncture of the aortic arch at the blood entry site of a thoracic type Ia endoleak after TEVAR and double-chimney stent-grafts with coil embolisation of the wedge-shaped space between the lesser aortic curvature and the stent-graft is possible. (orig.)

  15. Posterior cerebral artery angle and the rupture of basilar tip aneurysms.

    Directory of Open Access Journals (Sweden)

    Allen L Ho

    Full Text Available Since the initial publication of the International Study of Unruptured Intracranial Aneurysms (ISUIA, management of unruptured intracranial aneurysms has been mainly based on the size of the aneurysm. The contribution of morphological characteristics to treatment decisions of unruptured aneurysms has not been well studied in a systematic and location specific manner. We present a large sample of basilar artery tip aneurysms (BTA that were assessed using a diverse array of morphological variables to determine the parameters associated with ruptured aneurysms. Demographic and clinical risk factors of aneurysm rupture were obtained from chart review. CT angiograms (CTA were evaluated with Slicer, an open source visualization and image analysis software, to generate 3-D models of the aneurysms and surrounding vascular architecture. Morphological parameters examined in each model included aneurysm volume, aspect ratio, size ratio, aneurysm angle, basilar vessel angle, basilar flow angle, and vessel to vessel angles. Univariate and multivariate analyses were performed to determine statistical significance. From 2008-2013, 54 patients with BTA aneurysms were evaluated in a single institution, and CTAs from 33 patients (15 ruptured, 18 unruptured were available and analyzed. Aneurysms that underwent reoperation, that were associated with arteriovenous malformations, or that lacked preoperative CTA were excluded. Multivariate logistic regression revealed that a larger angle between the posterior cerebral arteries (P1-P1 angle, p = 0.037 was most strongly associated with aneurysm rupture after adjusting for other morphological variables. In this location specific study of BTA aneurysms, the larger the angle formed between posterior cerebral arteries was found to be a new morphological parameter significantly associated with ruptured BTA aneurysms. This is a physically intuitive parameter that can be measured easily and readily applied in the clinical

  16. Experimental behavior of FRP strengthened masonry arches

    OpenAIRE

    Oliveira, Daniel V.; Basílio, Ismael; Lourenço, Paulo B.

    2010-01-01

    This paper deals with the experimental behavior of solid clay brick masonry arches strengthened with glass fiber reinforced polymer composites. Twelve half-scaled segmental masonry arches subjected to a load applied at the quarter span were tested under displacement control up to failure. The arches were built using handmade low strength bricks and a commercial lime-based mortar, trying to mimic ancient structures. Besides reference unreinforced arches, five different strengthening arrangemen...

  17. Track-Bridge Longitudinal Interaction of Continuous Welded Rails on Arch Bridge

    Directory of Open Access Journals (Sweden)

    Rong Chen

    2013-01-01

    Full Text Available Taking arch bridges, including deck, half-through, and through arch bridges (short for DAB, HTAB, and TAB as examples, mechanics analysis models of longitudinal interaction between continuously welded rails (short for CWRs and arch bridges are established. Based on the finite element method (FEM, the longitudinal interaction calculation software of CWR on arch bridges has been developed. Focusing on an HTAB, the tension, compression, and deflection conditions are calculated and analyzed. The results show that the mechanics analysis models of three types of arch bridges can truly reflect the real state of the structure; the calculation software can be used for systematic research of the CWR on arch bridge; as for HTAB, temperature difference of arch rib has a small effect on rail tension/compression, and arch bridge can be simplified as a continuous beam for rail tension/compression additional force calculation; in calculation of deflection conditions of HTAB, it is suggested that train loads are arranged on half span and full span and take the direction of load entering bridge into account. Additionally, the deflection additional force variation of CFST basket handle arch bridge is different from that of ordinary bridge.

  18. A refined method for creating saccular aneurysms in the rabbit

    International Nuclear Information System (INIS)

    We describe a refined animal model of human intracerebral aneurysms for testing endovascular devices for interventional neuroradiological procedures. Saccular aneurysms resulting from a stump of the right common carotid artery (CCA) were created in 15 New Zealand White rabbits by intraluminal incubation of elastase that was applied to the CCA after distal ligation of the CCA and proximal occlusion of the vessel using a pliable balloon. Subsequently a microcatheter was advanced to a position cranial to the balloon and the elastase was infused under fluoroscopic guidance to avoid retrograde flow to the trachea via aberrant vessels. Contrast-enhanced (CE) MRA at 1.5 T and conventional digital subtraction angiography was performed to test for aneurysm size, morphology and neck anatomy. In all 15 animals aneurysms resulted from the stump of the right CCA, ranging in size from 2.0 to 9.9 mm (mean 6.3 mm) in craniocaudal direction, 1.0 to 5.5 mm (mean 3.8 mm) in mediolateral direction and 1.0 to 3.8 mm (mean 2.4 mm) in neck diameter. Aneurysm morphology could be adequately demonstrated using CE MRA. On histological evaluation a loss of the internal elastic lamina was noted. The described method represents an easy, reliable, and reproducible method of aneurysm creation in the rabbit in an area of high shear stress. These aneurysms can be used for testing new endovascular devices for embolization of intracranial aneurysms. (orig.)

  19. Popliteal vein aneurysm.

    Science.gov (United States)

    Falkowski, A; Poncyljusz, W; Zawierucha, D; Kuczmik, W

    2006-06-01

    The incidence of a popliteal vein aneurysm is extremely low. Two cases of this rare venous anomaly are described. The epidemiology, morphology, and diagnostic methods are discussed and the potentially dangerous complications and treatment methods are presented. PMID:16796307

  20. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... wall will actually thin out. And the big risk here is that if this gets too big ... to the aging baby boomers. Next slide. The risk factors for abdominal aortic aneurysms are males over ...

  1. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... moving inside in the aneurysm sack with the spine projected in the background. So how long have ... have a much more rapid recovery than open surgery. What do you think about that, Ignacio, compared ...

  2. Brain Aneurysm Foundation

    Science.gov (United States)

    ... … Continue Reading Read All News Latest Research NEWTON 2 Study Details October 7, 2016 05/29/ ... Oral Nimodipine in Adults With Aneurysmal Subarachnoid Hemorrhage (NEWTON 2) Details: Edge Therapeutics is recruiting patients ...

  3. Intracranial Arterial Aneurysms

    OpenAIRE

    J Gordon Millichap

    1988-01-01

    Neurosurgeons from the Universita degli Studi di Roma “La Saspeinza,” Rome, Italy, report a 4-year-old girl with a cerebral saccular aneurysm and analyze 71 cases under 5 years of age in the literature.

  4. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... been following in the institute for the past three years, and his aneurysm has now grown to ... may get for other reasons, but we use three-dimensional reconstruction and we can reconstruct all the ...

  5. Comparison of Commercially Available Arch Wires with Normal Dental Arch in a Group of Iranian Population

    OpenAIRE

    Zohreh Hedayati; Farnaz Fakhri; Vahid Moshkel Gosha

    2015-01-01

    Statement of the Problem The stability of orthodontic treatment depends on preserving the patient’s pretreatment arch form and arch size during and after treatment. Purpose This investigation was aimed to study the size and shape of Iranian mandibular dental arch and evaluate the correlation of their average dental arch with commercially available preformed rectangular nickel-titanium arch wires. Materials and Method In this study, 148 subjects were selected among students of Shiraz Universit...

  6. Haemodynamics of giant cerebral aneurysm: A comparison between the rigid-wall, one-way and two-way FSI models

    Science.gov (United States)

    Khe, A. K.; Cherevko, A. A.; Chupakhin, A. P.; Bobkova, M. S.; Krivoshapkin, A. L.; Orlov, K. Yu

    2016-06-01

    In this paper a computer simulation of a blood flow in cerebral vessels with a giant saccular aneurysm at the bifurcation of the basilar artery is performed. The modelling is based on patient-specific clinical data (both flow domain geometry and boundary conditions for the inlets and outlets). The hydrodynamic and mechanical parameters are calculated in the frameworks of three models: rigid-wall assumption, one-way FSI approach, and full (two-way) hydroelastic model. A comparison of the numerical solutions shows that mutual fluid- solid interaction can result in qualitative changes in the structure of the fluid flow. Other characteristics of the flow (pressure, stress, strain and displacement) qualitatively agree with each other in different approaches. However, the quantitative comparison shows that accounting for the flow-vessel interaction, in general, decreases the absolute values of these parameters. Solving of the hydroelasticity problem gives a more detailed solution at a cost of highly increased computational time.

  7. Simulation of Cerebral Aneurysm Growth and Prediction of Evolving Rupture Risk

    Directory of Open Access Journals (Sweden)

    Martin Kroon

    2011-01-01

    Full Text Available Cerebral aneurysms are local expansions of blood vessel walls in the brain blood system. The rupture of an aneurysm is a very severe event associated with a high rate of mortality. When cerebral aneurysms are detected, clinicians need to decide if operation is required. The risk of aneurysm rupture is then compared to the risks associated with the medical intervention. In the present paper, a probabilistic framework for a mechanically based rupture risk assessment of cerebral aneurysms is proposed. The method is based on the assumption that the strength of aneurysmal tissues can be described by a statistical distribution. A structural analysis of the aneurysm in question is performed, and the maximum stress experienced by the aneurysm is compared to the strength distribution. The proposed model was compared with clinical results for ruptured aneurysms in terms of rupture density and accumulated rupture risk as a function of aneurysm size. The model was able to reproduce the clinical results well. The proposed framework may potentially be used under in vivo conditions to predict the risk of rupture for diagnosed aneurysms.

  8. Treatment of infrarenal abdominal aortic dissection concomitant with an aneurysm

    Institute of Scientific and Technical Information of China (English)

    WANG Li-xin; ZHU Ting; FU Wei-guo; WANG Yu-qi; XI Xun; GUO Da-qiao; CHEN Bin; JIANG Jun-hao; YANG Ju; SHI Zhen-yu

    2007-01-01

    @@ Aortic dissection occurs when layers of the aortic walls are separated by the blood flow through an intimal tear. Dissection of the aorta most frequently originates in the ascending aorta (70%), followed by the descending aorta (22%), the aortic arch (7%) and the abdominal aorta (1/%).1 The dissection limited to the abdominal aorta is rare.2 An isolated abdominal aortic dissection (IAAD) concomitant with an abdominal aortic aneurysm (AAA) is uncommon. We present here one patient with IAAD and AAA treated by endovascular therapy.

  9. The Layout and Simulation of Logarithmic Spiral Double Curved Arch Dam Transverse Joints%The Layout and Simulation of Logarithmic Spiral Double Curved Arch Dam Transverse Joints

    Institute of Scientific and Technical Information of China (English)

    DU Ting-na; DU Qi-lu; HUI Yuan

    2011-01-01

    Because of its good condition with mechanics, logarithmic spiral double curve arch bam has been widely used in the practical engineering. The introduction of a new method in how to divide transverse joint in arch dam will be given and the further research of its calculation has been done. The C++ is used in electronic procedure and the 3D simulation has been finished with AutoCAD, which will provide the object model for computer simulation of the arch dam and the division of finite element mesh. Meanwhile, this method in dividing the transverse joint in arch dam also can be taken as the calculated basis for the design and calculation of arch dam, construction lofting and the calculation of the work amount.

  10. Comparison of Commercially Available Arch Wires with Normal Dental Arch in a Group of Iranian Population

    Directory of Open Access Journals (Sweden)

    Zohreh Hedayati

    2015-06-01

    Full Text Available Statement of the Problem: The stability of orthodontic treatment depends on preserving the patient’s pretreatment arch form and arch size during and after treatment. Purpose: This investigation was aimed to study the size and shape of Iranian mandibular dental arch and evaluate the correlation of their average dental arch with commercially available preformed rectangular nickel-titanium arch wires. Materials and Method: In this study, 148 subjects were selected among students of Shiraz University of Medical Sciences. The inclusion criteria were having Angle class I in molar and canine relationships, and normal growth pattern. Intercanine and intermolar widths were measured after scanning their mandibular dental casts. Three main arch form templates; square, ovoid and tapered (Orthoform TM; 3M, Unitek, CA, USA and 12 commercially available preformed mandibular nickel-titanium arch wires were scanned. Intercanine and intermolar widths of arch wires were compared with dental arch widths of the study samples. Arch width, arch form and the most appropriate arch wire were determined for each cast. Student’s t-test was used to compare arch widths and arch depths of male and female sub-jects. Coefficient of variance was used to determine the variability of indices in the study samples. Results: Most preformed arch wires were wider than the average width of the nor-mal Iranian dental arch. The most frequent arch form in Iranian population was tapered. Inter molar width was the only statistically significant variable between males and females. Conclusion: Variation in available preformed arch wires does not entirely cover the range of diversity of the normal dental arch of our population. Narrow arc

  11. Study on Forest Products PPI Index Fluctuation in China Based on ARCH Family-HP Filter Model%中国林产品PPI指数波动的ARCH族-HP滤波分析

    Institute of Scientific and Technical Information of China (English)

    张宇青; 周应恒

    2013-01-01

    了解林产品生产者价格指数波动的特征对稳定林产品PPI和价格水平有重要意义。采用ARCH-LM和残差平方和相关图方法检验后认为:木材、竹材PPI序列不存在不存在ARCH效应;HP滤波分析显示木材和竹材行业的P P I指数长期趋势比较平稳,相比于木材市场,近期竹材的市场供求状态相对合理;采用GARCH-M、 TARCH和EARCH模型分析认为胶脂和果实类林产品市场不存在“高风险-高收益”特征,但胶脂和果实类林产品PPI指数波动存在非对称性。%It’s important to Learn characteristics of forest products producer price index volatility for stable PPI and the price level. After Using ARCH-LM and the residual sum of squares correlation di-agram method. We considerst that: wood, bamboo PPI does not exist ARCH effect, HP filter analy-sis shows wood and bamboo industry PPI index slong-term trend is relatively stable, compared to the timber market, supply and demand status of bamboo market relatively reasonable;using GARCH-M, TARCH and EARCH model analysis that plastic resin and fruit category forest products does not exist“high risk - high return” feature, but it’s PPI index fluctuations exist asymmetry.

  12. Mast Cells in Abdominal Aortic Aneurysms

    DEFF Research Database (Denmark)

    Shi, Guo-Ping; Lindholt, Jes Sanddal

    2013-01-01

    , outer media and adventitia inflammation, aortic wall expansion, endothelium erosion, and eventual rupture and thrombosis. Experimental animal AAA models and MC reconstitution technique allowed examination of a direct role of MCs in AAA pathogenesis, and identification of the exact role of each MC......, and two cohort studies showing the systemic level of MC specific chymase and tryptase is associated with aneurysmal growth rate, need for later aneurysmal repair and even overall mortality. These observations offer new opportunities to prevent or slow AAA growth in humans, and specific antimastcell drugs...

  13. Comparison between CBCT and plaster models in measuring dental arches%锥形束CT数字化牙颌测量与石膏模型测量的对比研究

    Institute of Scientific and Technical Information of China (English)

    王珊; 韩越; 张卫兵; 王林

    2015-01-01

    目的:确定利用锥形束容积体层成像技术( cone-beam computed tomography,CBCT)数字化牙颌测量得到的数据与石膏模型测量数据是否具有一致性。方法对110例患者的CBCT重建影像进行牙颌测量,和石膏模型测量进行配对研究。使用Mimics软件重建并测量由NewTom VGi锥束CT扫描仪所形成的三维影像,同时制取超硬石膏模型。由测量人员分别进行拥挤量、拥挤度、前牙覆牙合覆盖、Bolton指数、上下颌尖牙间宽度、前磨牙间宽度、磨牙间宽度等数据进行测量,用Wilcoxon非参数检验对比分析测量结果。结果拥挤度、前牙覆牙合覆盖、前牙Bolton指数、第一前磨牙间宽度、第一磨牙间宽度两者测量结果无显著性差异;拥挤量、上下颌尖牙间宽度、全牙Bolton比两者测量结果有显著性差异,但拥挤量、上下颌尖牙间宽度两者均值差异均小于1 mm,全牙Bolton比差值小于1%。结论 CBCT数字化牙颌测量和石膏模型在大部分测量值上具有一致性,有可能在未来替代传统石膏模型测量简化临床操作。%Objective To compare cone-beam computed tomography ( CBCT) and dental plaster model ( DPM) in the measurement of the dental arches. Methods The dental arches of 110 patients were scanned with the CBCT and their DPMs were also obtained. The Mimics software was used to reconstruct as well as measure the three dimensional images scanned by NewTom VGi CT,and ultra-hard DPMs were fab-ricated. Two experienced examiners collected eight arch measurements on the CBCT images and DPMs,and coupled arch measurements of these two clinical detection methods were compared separately by the Wilcoxon signed-rank test. Results No significant difference between DPM and CBCT were found in five arch measurements (P>0. 01). Although there was statistical difference between DPM and CBCT in space analysis,width between canine,and total dental Bolton index (P<0. 01),the mean

  14. Risk of Familial Intracranial Aneurysm

    OpenAIRE

    J Gordon Millichap; John J Millichap

    2014-01-01

    Investigators at University Medical Center Utrecht, Netherlands, studied the yield of long-term (up to 20 years) screening for intracranial aneurysms in individuals with a positive family history (2 or more first-degree relatives) of aneurysmal subarachnoid hemorrhage (aSAH) or unruptured intracranial aneurysm (1993-2013).

  15. Blood flow characteristics in the aortic arch

    Science.gov (United States)

    Prahl Wittberg, Lisa; van Wyk, Stevin; Mihaiescu, Mihai; Fuchs, Laszlo; Gutmark, Ephraim; Backeljauw, Philippe; Gutmark-Little, Iris

    2012-11-01

    The purpose with this study is to investigate the flow characteristics of blood in the aortic arch. Cardiovascular diseases are associated with specific locations in the arterial tree. Considering atherogenesis, it is claimed that the Wall Shear Stress (WSS) along with its temporal and spatial gradients play an important role in the development of the disease. The WSS is determined by the local flow characteristics, that in turn depends on the geometry as well as the rheological properties of blood. In this numerical work, the time dependent fluid flow during the entire cardiac cycle is fully resolved. The Quemada model is applied to account for the non-Newtonian properties of blood, an empirical model valid for different Red Blood Cell loading. Data obtained through Cardiac Magnetic Resonance Imaging have been used in order to reconstruct geometries of the the aortic arch. Here, three different geometries are studied out of which two display malformations that can be found in patients having the genetic disorder Turner's syndrome. The simulations show a highly complex flow with regions of secondary flow that is enhanced for the diseased aortas. The financial support from the Swedish Research Council (VR) and the Sweden-America Foundation is gratefully acknowledged.

  16. The Arches Cluster Mass Function

    CERN Document Server

    Kim, S S; Kudritzki, R P; Najarro, F; Kim, Sungsoo S.; Figer, Donald F.; Kudritzki, Rolf P.

    2006-01-01

    We have analyzed H and K_s-band images of the Arches cluster obtained using the NIRC2 instrument on Keck with the laser guide star adaptive optics (LGS AO) system. With the help of the LGS AO system, we were able to obtain the deepest ever photometry for this cluster and its neighborhood, and derive the background-subtracted present-day mass function (PDMF) down to 1.3 Msun for the 5 arcsec-9 arcsec annulus of the cluster. We find that the previously reported turnover at 6 Msun is simply due to a local bump in the mass function (MF), and that the MF continues to increase down to our 50 % completeness limit (1.3 Msun) with a power-law exponent of Gamma = -0.91 for the mass range of 1.3 < M/Msun < 50. Our numerical calculations for the evolution of the Arches cluster show that the Gamma values for our annulus increase by 0.1-0.2 during the lifetime of the cluster, and thus suggest that the Arches cluster initially had Gamma of -1.0 ~ -1.1, which is only slightly shallower than the Salpeter value.

  17. A study of the hemodynamics of anterior communicating artery aneurysms

    Science.gov (United States)

    Cebral, Juan R.; Castro, Marcelo A.; Putman, Christopher M.

    2006-03-01

    In this study, the effects of unequal physiologic flow conditions in the internal carotid arteries on the intra-aneurysmal hemodynamics of anterior communicating artery aneurysms were investigated. Patient-specific vascular computational fluid dynamics models of five cerebral aneurysms were constructed from bilateral 3D rotational angiography images. The aneurysmal hemodynamics was analyzed under a range of physiologic flow conditions including the effects of unequal mean flows and phase shifts between the flow waveforms of the left and right internal carotid arteries. A total of five simulations were performed for each patient, and unsteady wall shear stress (WSS) maps were created for each flow condition. Time dependent curves of average WSS magnitude over selected regions on the aneurysms were constructed and used to analyze the influence of the inflow conditions. It was found that mean flow imbalances in the feeding vessels tend to shift the regions of elevated WSS (flow impingement region) towards the dominating inflow jet and to change the magnitude of the WSS peaks. However, the overall qualitative appearance of the WSS distribution and velocity simulations is not substantially affected. In contrast, phase differences tend to increase the temporal complexity of the hemodynamic patterns and to destabilize the intra-aneurysmal flow pattern. However, these effects are less important when the A1 confluence is less symmetric, i.e. dominated by one of the A1 segments. Conditions affecting the flow characteristics in the parent arteries of cerebral aneurysms with more than one avenue of inflow should be incorporated into flow models.

  18. [Inflammatory abdominal aortic aneurysm].

    Science.gov (United States)

    Ziaja, K; Sedlak, L; Urbanek, T; Kostyra, J; Ludyga, T

    2000-01-01

    The reported incidence of inflammatory abdominal aortic aneurysm (IAAA) is from 2% to 14% of patients with abdominal aortic aneurysm and the etiology of this disease is still discussed--according to the literature several pathogenic theories have been proposed. From 1992 to 1997 32 patients with IAAA were operated on. The patients were mostly symptomatic--abdominal pain was present in 68.75% cases, back pain in 31.25%, fever in 12.5% and weight loss in 6.25% of the operated patients. In all the patients ultrasound examination was performed, in 4 patients CT and in 3 cases urography. All the patients were operated on and characteristic signs of inflammatory abdominal aortic aneurysm like: thickened aortic wall, perianeurysmal infiltration or retroperitoneal fibrosis with involvement of retroperitoneal structures were found. In all cases surgery was performed using transperitoneal approach; in three cases intraoperatively contiguous abdominal organs were injured, which was connected with their involvement into periaortic inflammation. In 4 cases clamping of the aorta was done at the level of the diaphragmatic hiatus. 3 patients (9.37%) died (one patient with ruptured abdominal aortic aneurysm). Authors present diagnostic procedures and the differences in the surgical tactic, emphasizing the necessity of the surgical therapy in patients with inflammatory abdominal aortic aneurysm.

  19. Combination of traumatic thoracic aortic pseudoaneurysm and myocardial contusion leading to left ventricular aneurysm

    International Nuclear Information System (INIS)

    The combination of thoracic aortic pseudoaneurysm and left ventricular aneurysm resulting from a single traumatic incident is an exceedingly rare occurrence. We present a case of a 10-year-old girl who sustained significant blunt trauma to the chest after being involved in a rollover motor vehicle accident. The child underwent immediate repair of a transected aortic arch. An inferior wall left ventricular aneurysm developed 3 weeks later, and the patient underwent successful repair of the left ventricular aneurysm and a damaged mitral valve. The use of fast multidetector row CT, cardiac MRI, and echocardiography have improved our ability to diagnose these types of injuries and accurately image their anatomic relationships in the acute and perioperative settings. (orig.)

  20. Verminous aneurysm caused by filaria.

    Science.gov (United States)

    Toledo, F V; de Araújo, A P; da Cunha, A M; Sidow, J R; Pavão, S G; de Araújo, E D

    1983-06-01

    Aneurysms caused by atherosclerosis are relatively frequent, as a consequence of the high incidence of this degenerative disease of the arteries. Other types of aneurysm, for example, those of infectious etiology, are more uncommon. Bacterias and fungi are able to cause aneurysms in several parts of the arterial tree. Stengel et al (1943), in a review of world literature described 217 cases of mycotic aneurysms. The Stedman's Medical Dictionary refers to a special type of aneurysm observed in horses, caused by intra-vascular migration of a worm, the Strongylus vulgaris. It has been named verminous aneurysm and generally involves the mesenteric arteries. We haven't found in medical literature any similar observations refering to human cases. The purpose of this paper is to describe a case of aneurysm the etiology of which we have imputed to the filaria (Wuchereria bancrofti). This case was observed in Marcilio Dias Naval Hospital, Rio de Janeiro, Brazil. PMID:6346961

  1. Optical silencing of C. elegans cells with arch proton pump.

    Directory of Open Access Journals (Sweden)

    Ayako Okazaki

    Full Text Available BACKGROUND: Optogenetic techniques using light-driven ion channels or ion pumps for controlling excitable cells have greatly facilitated the investigation of nervous systems in vivo. A model organism, C. elegans, with its small transparent body and well-characterized neural circuits, is especially suitable for optogenetic analyses. METHODOLOGY/PRINCIPAL FINDINGS: We describe the application of archaerhodopsin-3 (Arch, a recently reported optical neuronal silencer, to C. elegans. Arch::GFP expressed either in all neurons or body wall muscles of the entire body by means of transgenes were localized, at least partially, to the cell membrane without adverse effects, and caused locomotory paralysis of worms when illuminated by green light (550 nm. Pan-neuronal expression of Arch endowed worms with quick and sustained responsiveness to such light. Worms reliably responded to repeated periods of illumination and non-illumination, and remained paralyzed under continuous illumination for 30 seconds. Worms expressing Arch in different subsets of motor neurons exhibited distinct defects in the locomotory behavior under green light: selective silencing of A-type motor neurons affected backward movement while silencing of B-type motor neurons affected forward movement more severely. Our experiments using a heat-shock-mediated induction system also indicate that Arch becomes fully functional only 12 hours after induction and remains functional for more than 24 hour. CONCLUSIONS/SGNIFICANCE: Arch can be used for silencing neurons and muscles, and may be a useful alternative to currently widely used halorhodopsin (NpHR in optogenetic studies of C. elegans.

  2. Aneurysmal Subarachnoid Hemorrhage and Neuroinflammation: A Comprehensive Review

    Science.gov (United States)

    Lucke-Wold, Brandon P.; Logsdon, Aric F.; Manoranjan, Branavan; Turner, Ryan C.; McConnell, Evan; Vates, George Edward; Huber, Jason D.; Rosen, Charles L.; Simard, J. Marc

    2016-01-01

    Aneurysmal subarachnoid hemorrhage (SAH) can lead to devastating outcomes including vasospasm, cognitive decline, and even death. Currently, treatment options are limited for this potentially life threatening injury. Recent evidence suggests that neuroinflammation plays a critical role in injury expansion and brain damage. Red blood cell breakdown products can lead to the release of inflammatory cytokines that trigger vasospasm and tissue injury. Preclinical models have been used successfully to improve understanding about neuroinflammation following aneurysmal rupture. The focus of this review is to provide an overview of how neuroinflammation relates to secondary outcomes such as vasospasm after aneurysmal rupture and to critically discuss pharmaceutical agents that warrant further investigation for the treatment of subarachnoid hemorrhage. We provide a concise overview of the neuroinflammatory pathways that are upregulated following aneurysmal rupture and how these pathways correlate to long-term outcomes. Treatment of aneurysm rupture is limited and few pharmaceutical drugs are available. Through improved understanding of biochemical mechanisms of injury, novel treatment solutions are being developed that target neuroinflammation. In the final sections of this review, we highlight a few of these novel treatment approaches and emphasize why targeting neuroinflammation following aneurysmal subarachnoid hemorrhage may improve patient care. We encourage ongoing research into the pathophysiology of aneurysmal subarachnoid hemorrhage, especially in regards to neuroinflammatory cascades and the translation to randomized clinical trials. PMID:27049383

  3. Use of the Structure of Blood Vessel for Detection of Brain Aneurysm and Route Search to Brain Aneurysm

    Directory of Open Access Journals (Sweden)

    Toshihide Miyagi

    2013-08-01

    Full Text Available In this research, we constructed functions that are necessary for the operation simulation system which assists medical students to inhibit brain aneurysm from exploding. The system reported in this paper is "detection of blood vessels", "detection of brain aneurysm" and "route planning to brain aneurysm". Not only the detection method but also the method to reduce the miss detection is realized for the detection of blood vessel. Finally, the future work will be shown including construction of head model consisting of artery, vein, brain and cranium.

  4. Evaluation of the fit of preformed nickel titanium arch wires on normal occlusion dental arches

    Directory of Open Access Journals (Sweden)

    Rakhn G. Al-Barakati

    2016-01-01

    Conclusions: Using an archwire form with the best fit to the dental arch should produce minimal changes in the dental arch form when NiTi wires are used and require less customization when stainless-steel wires are used.

  5. Pediatric intracranial aneurysms.

    Science.gov (United States)

    Tripathy, L N; Singh, S N

    2009-01-01

    The incidence of subarachnoid haemorrhage from intracranial aneurysms in the paediatric age group is extremely rare. Interestingly, occurrence of vasospasm has been reported to be less in comparison to the adults. Both coiling and clipping have been advocated in selected cases. Because of the thinness of the wall of the arteries, utmost care should be taken while handling these arteries during surgery. The overall results of surgery in children have been reported to be better than their adult counterparts. We present four such cases from our own experience. All these children were operated upon, where the solitary aneurysm in each case was clipped and all of them made a good recovery.

  6. Pulsatile blood flow in Abdominal Aortic Aneurysms

    Science.gov (United States)

    Salsac, Anne-Virginie; Lasheras, Juan C.; Singel, Soeren; Varga, Chris

    2001-11-01

    We discuss the results of combined in-vitro laboratory measurements and clinical observations aimed at determining the effect that the unsteady wall shear stresses and the pressure may have on the growth and eventual rupturing of an Abdominal Aortic Aneurysm (AAA), a permanent bulging-like dilatation occurring near the aortic bifurcation. In recent years, new non-invasive techniques, such as stenting, have been used to treat these AAAs. However, the development of these implants, aimed at stopping the growth of the aneurysm, has been hampered by the lack of understanding of the effect that the hemodynamic forces have on the growth mechanism. Since current in-vivo measuring techniques lack the precision and the necessary resolution, we have performed measurements of the pressure and shear stresses in laboratory models. The models of the AAA were obtained from high resolution three-dimensional CAT/SCANS performed in patients at early stages of the disease. Preliminary DPIV measurements show that the pulsatile blood flow discharging into the cavity of the aneurysm leads to large spikes of pressure and wall shear stresses near and around its distal end, indicating a possible correlation between the regions of high wall shear stresses and the observed location of the growth of the aneurysm.

  7. Morphological and hemodynamic analysis of mirror posterior communicating artery aneurysms.

    Directory of Open Access Journals (Sweden)

    Jinyu Xu

    Full Text Available BACKGROUND AND PURPOSE: Hemodynamic factors are commonly believed to play an important role in the pathogenesis, progression, and rupture of cerebral aneurysms. In this study, we aimed to identify significant hemodynamic and morphological parameters that discriminate intracranial aneurysm rupture status using 3-dimensional-angiography and computational fluid dynamics technology. MATERIALS AND METHODS: 3D-DSA was performed in 8 patients with mirror posterior communicating artery aneurysms (Pcom-MANs. Each pair was divided into ruptured and unruptured groups. Five morphological and three hemodynamic parameters were evaluated for significance with respect to rupture. RESULTS: The normalized mean wall shear stress (WSS of the aneurysm sac in the ruptured group was significantly lower than that in the unruptured group (0.52±0.20 versus 0.81±0.21, P = .012. The percentage of the low WSS area in the ruptured group was higher than that in the unruptured group (4.11±4.66% versus 0.02±0.06%, P = .018. The AR was 1.04±0.21 in the ruptured group, which was significantly higher than 0.70±0.17 in the unruptured group (P = .012. By contrast, parameters that had no significant differences between the two groups were OSI (P = .674, aneurysm size (P = .327, size ratio (P = .779, vessel angle (P = 1.000 and aneurysm inclination angle (P = 1.000. CONCLUSIONS: Pcom-MANs may be a useful disease model to investigate possible causes of aneurysm rupture. The ruptured aneurysms manifested lower WSS, higher percentage of low WSS area, and higher AR, compared with the unruptured one. And hemodynamics is as important as morphology in discriminating aneurysm rupture status.

  8. Seismic response analysis of arch dam-water-rock foundation systems

    Institute of Scientific and Technical Information of China (English)

    杜修力; 王进廷

    2004-01-01

    The effect of water compressibility on the seismic responses of arch dams is not well understood. In this paper, a numerical model is developed with rigorous representation of the dynamic interaction between arch dam-waterrock foundation. The model is applied to the seismic response analysis of an arch dam with a height of 292m designed to a seismic intensity of Ⅸ. It is shown that consideration of the water compressibility clearly decreases the stress responses at key positions of the dam, while the added mass model gives a conservative estimate.

  9. What You Should Know about Cerebral Aneurysms

    Science.gov (United States)

    ... T. Quiz 5 Things to Know About Stroke What You Should Know About Cerebral Aneurysms Updated:Jun ... Damage Treatments Click image to view an animation What is a cerebral aneurysm? An aneurysm is a ...

  10. Mirror aneurysms : a reflection on natural history

    NARCIS (Netherlands)

    Meissner, Irene; Torner, James; Huston III, John; Rajput, Michele L.; Wiebers, David O.; Jones, Lyell K.; Brown, Robert D.; Groen, Rob

    2012-01-01

    OBJECT: Investigators conducting the International Study of Unruptured Intracranial Aneurysms, sponsored by the National Institutes of Health, sought to evaluate predictors of future hemorrhage in patients who had unruptured mirror aneurysms. These paired aneurysms in bilateral arterial positions mi

  11. The effect of inlet waveforms on computational hemodynamics of patient-specific intracranial aneurysms.

    Science.gov (United States)

    Xiang, J; Siddiqui, A H; Meng, H

    2014-12-18

    Due to the lack of patient-specific inlet flow waveform measurements, most computational fluid dynamics (CFD) simulations of intracranial aneurysms usually employ waveforms that are not patient-specific as inlet boundary conditions for the computational model. The current study examined how this assumption affects the predicted hemodynamics in patient-specific aneurysm geometries. We examined wall shear stress (WSS) and oscillatory shear index (OSI), the two most widely studied hemodynamic quantities that have been shown to predict aneurysm rupture, as well as maximal WSS (MWSS), energy loss (EL) and pressure loss coefficient (PLc). Sixteen pulsatile CFD simulations were carried out on four typical saccular aneurysms using 4 different waveforms and an identical inflow rate as inlet boundary conditions. Our results demonstrated that under the same mean inflow rate, different waveforms produced almost identical WSS distributions and WSS magnitudes, similar OSI distributions but drastically different OSI magnitudes. The OSI magnitude is correlated with the pulsatility index of the waveform. Furthermore, there is a linear relationship between aneurysm-averaged OSI values calculated from one waveform and those calculated from another waveform. In addition, different waveforms produced similar MWSS, EL and PLc in each aneurysm. In conclusion, inlet waveform has minimal effects on WSS, OSI distribution, MWSS, EL and PLc and a strong effect on OSI magnitude, but aneurysm-averaged OSI from different waveforms has a strong linear correlation with each other across different aneurysms, indicating that for the same aneurysm cohort, different waveforms can consistently stratify (rank) OSI of aneurysms. PMID:25446264

  12. Endovascular treatment of experimental aneurysms in rabbits using Guglielmi detachable coils - a feasibility study

    International Nuclear Information System (INIS)

    The Guglielmi detachable coil (GDC) has been generally accepted for treatment of intracranial aneurysms. Preclinical testing of new coil developments requires animal models of aneurysms which imitate human aneurysms in size, configuration and neck morphology. We assessed in detail the technical requirements and steps for transfemoral treatment of experimentally induced aneurysms at the top of the brachiocephalic trunk (TBC) in rabbits. We created aneurysms in five rabbits by distal ligation and intraluminal incubation of the right common carotid artery with elastase. All animals were treated successfully 2-3 weeks after induction of the aneurysm, with dense packing of the coils. No complications related to the procedures occurred. The study demonstrates that our animal model can be a suitable method for testing the biocompatibility and occlusion rate of new embolic materials. (orig.)

  13. Endovascular stent graft repair for thoracic aortic aneurysms: the history and the present in Japan.

    Science.gov (United States)

    Kawaguchi, Satoshi; Shimizu, Hideyuki; Yoshitake, Akihiro; Shimazaki, Taro; Iwahashi, Toru; Ogino, Hitoshi; Ishimaru, Shin; Shigematsu, Hiroshi; Yozu, Ryohei

    2013-01-01

    Stent-grafts for endovascular repair of thoracic aortic aneurysms have been commercially available for more than ten years in the West, whereas, in Japan, a manufactured stent-graft was not approved for the use until March 2008. Nevertheless, endovascular thoracic intervention began to be performed in Japan in the early 1990s, with homemade devices used in most cases. Many researchers have continued to develop their homemade devices. We have participated in joint design and assessment efforts with a stent-graft manufacturer, focusing primarily on fenestrated stent-grafts used in repairs at the distal arch, a site especially prone to aneurysm. In March 2008, TAG (W.L. Gore & Associates, Inc., Flagstaff, Arizona, USA) was approved as a stent graft for the thoracic area first in Japan, which was major turning point in treatment for thoracic aortic aneurysms. Subsequently, TALENT (Medtronic, Inc., Minneapolis, Minnesota, USA) was approved in May 2009, and TX2 (COOK MEDICAL Inc., Bloomington, Indiana, USA) in March 2011. Valiant as an improved version of TALENT was approved in November 2011, and TX2 Proform as an improved version of TX2 began to be supplied in October 2012. These stent grafts are excellent devices that showed good results in Western countries, and marked effectiveness can be expected by making the most of the characteristics of each device. A clinical trial in Japan on Najuta (tentative name) (Kawasumi Labo., Inc., Tokyo, Japan) as a line-up of fenestrated stent grafts that can be applied to distal arch aneurysms showing a high incidence, and allow maintenance of blood flow to the arch vessel was initiated. This trial was completed, and Najuta has just been approved in January of 2013 in Japan, and further development is expected. In the U.S., great efforts have recently been made to develop and manufacture excellent stent grafts for thoracic aneurysms, and rapid progress has been achieved. In particular, in the area of the aortic arch, in which we

  14. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... microchip that acts a little bit like a cell phone technology. We’ll show you how that works. But this is the device that we’re going to put in that space between the endograft and the patient to the wall of the aneurysm. So in that space where ...

  15. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... for all of you listening, you can ask online. Just click the “Ask a question” button, and ... aneurysm. Please feel free to ask any questions online. Just click “Ask a question,” and they’ll ...

  16. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... racquet-like device whether or not there is flow in this sack after we replace in aneurysm. ... space age. That’s fine. Don’t go too high. Pull it down a little bit. Pull that ...

  17. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... an aneurysm, it’s important that you ask your doctor about your options. As I said, about 80 percent of the patients we treat end up -- 80 or 90 percent these days, end up being good candidates for this type of therapy. We would encourage you to seek the least ...

  18. Inflammatory aortic aneurysms

    DEFF Research Database (Denmark)

    Bitsch, M; Nørgaard, H H; Røder, O;

    1997-01-01

    operated on for abdominal aortic aneurysms without PF in the same period, served as reference group. RESULTS: Preoperative thickness of PF was assessed as > 1 cm in 11 and cm in 10 patients. Ureterolysis was performed in seven patients where the fibrosis caused ureteral obstruction. Postoperative CT...

  19. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... to repair an abdominal aortic aneurysm using a technology called an “endograft,” which is sometimes called the “ ... separate area, and it’s because of this small technology that allows you to do this. Exactly. So ...

  20. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... an abdominal aortic aneurysm. Normally this procedure takes us about 45 minutes to an hour of doctor work time, which is, I think, a fairly quick procedure to replace a major life-threatening problem in the patient’s abdomen. So you can see ...

  1. A Comparison Study of Stress Distribution Around Dental Implants in Three Mandibular Arch Types by Finite lement Analysis

    OpenAIRE

    Monzavi A.; Farhang Gh R

    2000-01-01

    The geometric shape of dental arch (square, tapering, ovoid) is an important factor in stress distribution pattern around dental implant. The aim of this study was to evaluate the role of arch form and the amount of bone loss (normal, moderate, high) in stress distribution around dental implant by considering different load direction. Three arch forms; square, ovoid, and tapering with three different stages of bone loss were designed. Models were divided into three-dimensional elements, which...

  2. Intra-aneurysmal flow reductions in a thin film nitinol flow diverter

    International Nuclear Information System (INIS)

    A novel hyper-elastic thin film nitinol (HE-TFN) covered stent has been developed to promote aneurysm occlusion by diminishing flow in the aneurysm. Laboratory aneurysm models were used to assess the flow changes produced by stents covered with different patterns of HE-TFN placed across the aneurysm neck in the parent vessel. The flow diverters were constructed by covering Wingspan stents (Boston Scientific) with different HE-TFNs (i.e., of 82% and 77% porosity) and deployed in both in vitro wide-neck and fusiform glass aneurysm models. In wide-neck aneurysms, the 82% porous HE-TFN stent reduced mean flow velocity in the middle of the sac by 86 ± 1%, while the 77% porous stent reduced the velocity by 93 ± 5% (n = 3). Local wall shear rates were also significantly reduced by about 98% in this model after device placement. Tests conducted on the fusiform aneurysm revealed smaller intra-aneurysmal flow velocity reduction by 48 ± 3% for the 82% porous stent and by 59 ± 7% for the 77% porous stent. The wall shear was reduced by approximately 50% by HE-TFN stents in fusiform models. These results suggest that HE-TFN covered stents have the potential to promote thrombosis in both wide-neck and fusiform aneurysm sacs

  3. A Novel Thin Film Nitinol Covered Neurovascular Stent Significantly Decreases Intra-Aneurysmal Flow In Vitro

    Science.gov (United States)

    Chun, Youngjae; Hur, Soojung; Shayan, Mahdis; Kealey, Colin; Levi, Daniel; Mohanchandra, Kp; di Carlo, Dino; Carman, Gregory

    2013-11-01

    A novel thin film nitinol (TFN) stent has been developed to promote aneurysm quiescence by diminishing flow across the aneurysm's neck. Laboratory aneurysm models were used to assess the flow changes produced by stents covered with different patterns of TFN. Flow diversion stents were constructed by covering Wingspan stents (Boston Scientific, DxL:4x20mm) with TFNs (i.e., 77 and 82 percent porosity). The flow changes that occur after deployment of two different porous TFN covered stent in intracranial aneurysm models were evaluated in vitro. The 82 percent porous TFN covered stent reduced the intra-aneurysmal mean flow velocity by 86.42 percent, while a 77 percent porous TFN covered stent reduced to intra-aneurysmal mean flow velocity to 93.44 percent compared to a nonstented model. Local wall shear rates were also significantly reduced in wide-neck aneurysm model (i.e., 97.52 - 98.92 percent) with TFN stent placement. The results showed that TFN covered stents significantly reduced intra-aneurysmal flow velocity magnitudes and local wall shear rates. This suggests that TFN covered stents with both 77 and 82 percent porosity have great potential to promote thrombosis in both wide-necked and fusiform aneurysm sacs.

  4. Computational fluid dynamics study of bifurcation aneurysms treated with pipeline embolization device: side branch diameter study

    OpenAIRE

    Tang, Abraham Yik-Sau; Chung, Wai-Choi; Liu, Eric Tian-Yang; Qu, Jie-Qiong; Tsang, Anderson Chun-On; Leung, Gilberto Ka-Kit; Leung, Kar-Ming; Yu, Alfred Cheuk-Hang; Chow, Kwok-Wing

    2015-01-01

    An intracranial aneurysm, abnormal swelling of the cerebral artery, may lead to undesirable rates of mortality and morbidity upon rupture. Endovascular treatment involves the deployment of a flow-diverting stent that covers the aneurysm orifice, thereby reducing the blood flow into the aneurysm and mitigating the risk of rupture. In this study, computational fluid dynamics analysis is performed on a bifurcation model to investigate the change in hemodynamics with various side branch diameters...

  5. Thoracic aortic aneurysm: A rare cause of elevated hemidiaphragm.

    Science.gov (United States)

    Ejazi, Md Arshad; Alam, Md Mazhar; Shameem, Mohammad; Bhargava, Rakesh; Adil Wafi, C G; Salauddin

    2016-01-01

    Phrenic nerve palsy causing hemidiaphragm paralysis is a very uncommon feature of thoracic aortic aneurysm. In one case, a 30 year male complained of chronic dull aching chest pain, and hoarseness of voice; posteroanterior view chest radiograph revealed large spherical radiopacity on the left upper lung zone with smooth lobulated margin with elevated left hemidiaphragm. On Colour Doppler sonography, lesion was anechoic on gray scale sonography but on Doppler analysis revealed intense internal vascularity within it with characteristic "Ying Yang" sign. The finding favor the vascular origin of the lesion and a diagnosis of an arterial aneurysm was made Contrast-enhanced computed tomography (CT) of the thorax revealed a large well defined spherical lesion of 8 × 10 cm size with smooth well defined margin arising from the aortic arch and attenuation of impending rupture or dissection were lesion on immediate post contrast and delayed scan was similar to that of aorta. Left hemidiaphragm elevation was explained by the gross mass effect of the aneurysm causing right phrenic nerve palsy. PMID:27578939

  6. Thoracic aortic aneurysm: A rare cause of elevated hemidiaphragm

    Directory of Open Access Journals (Sweden)

    Md Arshad Ejazi

    2016-01-01

    Full Text Available Phrenic nerve palsy causing hemidiaphragm paralysis is a very uncommon feature of thoracic aortic aneurysm. In one case, a 30 year male complained of chronic dull aching chest pain, and hoarseness of voice; posteroanterior view chest radiograph revealed large spherical radiopacity on the left upper lung zone with smooth lobulated margin with elevated left hemidiaphragm. On Colour Doppler sonography, lesion was anechoic on gray scale sonography but on Doppler analysis revealed intense internal vascularity within it with characteristic "Ying Yang" sign. The finding favor the vascular origin of the lesion and a diagnosis of an arterial aneurysm was made Contrast-enhanced computed tomography (CT of the thorax revealed a large well defined spherical lesion of 8 × 10 cm size with smooth well defined margin arising from the aortic arch and attenuation of impending rupture or dissection were lesion on immediate post contrast and delayed scan was similar to that of aorta. Left hemidiaphragm elevation was explained by the gross mass effect of the aneurysm causing right phrenic nerve palsy.

  7. Tympanic ossicles and pharyngeal arches.

    Science.gov (United States)

    Whyte, J; Cisneros, A; Yus, C; Fraile, J; Obón, J; Vera, A

    2009-02-01

    We have performed a study on 11 human embryos regarding the development of the tympanic ossicles and their relationship with the first pharyngeal arch. After performing measurements to date the embryos and foetuses chronologically, we performed a meticulous dissection of the temporal bones. Subsequently, they were fixed in 10% formol, decalcified with 2% nitric acid, embedded in Paraplast, sectioned in 7-mm sequences and stained with Martin's trichrome technique. In the 21- and 24-mm cranium-raquis (CR) length human embryos, we have observed the head of the malleus and the body of the incus close to Meckel's cartilage, in addition to the handle of the malleus, the long limb of the incus and the stapes. Between them there was a mesenchymal band inside the primordium of the tympanic cavity. In the 27-mm CR embryo, the various components of the malleus and incus were fusing, and in the 30-mm CR embryo the union was complete. From our observations, we can conclude that the malleus and the incus are derived from the first and second pharyngeal arches.

  8. Comparison of arch form between ethnic Malays and Malaysian Aborigines in Peninsular Malaysia

    OpenAIRE

    Othman, Siti Adibah; Xinwei, Eunice Soh; Lim, Sheh Yinn; Jamaludin, Marhazlinda; Mohamed, Nor Himazian; Yusof, Zamros Yuzaidi Mohd; Shoaib, Lily Azura; Nik Hussein, Nik Noriah

    2012-01-01

    Objective: To determine and compare the frequency distribution of various arch shapes in ethnic Malays and Malaysian Aborigines in Peninsular Malaysia and to investigate the morphological differences of arch form between these two ethnic groups. Methods: We examined 120 ethnic Malay study models (60 maxillary, 60 mandibular) and 129 Malaysian Aboriginal study models (66 maxillary, 63 mandibular). We marked 18 buccal tips and incisor line angles on each model, and digitized them using 2-dimens...

  9. Maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width groups

    Science.gov (United States)

    Shahid, Fazal; Alam, Mohammad Khursheed; Khamis, Mohd Fadhli

    2015-01-01

    Objective: To investigate the maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width (intercanine, interpremolar, and intermolar) groups. Materials and Methods: The calculated sample size was 128 subjects. The crown width/height, arch length, arch perimeter, and arch width of the maxilla and mandible were obtained via digital calliper (Mitutoyo, Japan). A total of 4325 variables were measured. The sex differences in the crown width and height were evaluated. Analysis of variance was applied to evaluate the differences between arch length, arch perimeter, and arch width groups. Results: Males had significantly larger mean values for crown width and height than females (P ≤ 0.05) for maxillary and mandibular arches, both. There were no significant differences observed for the crown width/height ratio in various arch length, arch perimeter, and arch width (intercanine, interpremolar, and intermolar) groups (P ≤ 0.05) in maxilla and mandible, both. Conclusions: Our results indicate sexual disparities in the crown width and height. Crown width and height has no significant relation to various arch length, arch perimeter, and arch width groups of maxilla and mandible. Thus, it may be helpful for orthodontic and prosthodontic case investigations and comprehensive management. PMID:26929686

  10. Techniques for aortic arch endovascular repair.

    Science.gov (United States)

    kHONGKU, Kiattisak; Dias, Nuno; Sonesson, Bjorn; Resch, Timothy

    2016-06-01

    This article reviews endovascular strategies for aortic arch repair. Open repair remains the gold standard particularly for good risk patients. Endovascular treatment potentially offers a less invasive repair. Principles, technical considerations, devices and outcomes of each technique are discussed and summarized. Hybrid repair combines less invasive revascularization options, instead of arch replacement while extending stent-graft into the arch. Outcomes vary with regard to extent of repair and aortic arch pathologies treated. Results of arch chimney and other parallel graft techniques perhaps make it a less preferable choice for elective cases. However, they are very appealing options for urgent or bailout situations. Fenestrated stent-grafting is subjected to many technical challenges in aortic arch due to difficulties in stent-graft orientation and fenestration positioning. In situ fenestration techniques emerge to avoid these problems, but durability of stent-grafts after fenestration and ischemic consequences of temporary carotid arteries coverage raises some concern total arch repair using this technique. Arch branched graft is a new technology. Early outcomes did not meet the expectation; however the results have been improving after its learning curve period. Refining stent-graft technologies and implantation techniques positively impact outcomes of endovascular approaches. PMID:26940011

  11. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography

    Science.gov (United States)

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-06-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems.

  12. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography.

    Science.gov (United States)

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-01-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems.

  13. Visualization of soil arching in flexible piled embankments

    Indian Academy of Sciences (India)

    Tuğba Eskışar

    2015-10-01

    Piled embankments rely on soil arching, but, when geogrid reinforcements are used, membrane action within the reinforcement contributes to load distribution. The arching of soil in unreinforced and reinforced piled embankments is evaluated in this study. A small-scale test apparatus is used to model the settlement up to 5 mm in an embankment with four pile elements. Visual inspection of the soil settlement and soil-reinforcement interaction is important to explain the mechanism of arching. In this study, X-ray Computed Tomography (CT) method was used as a non-destructive technique. The arching of soil between the piles was observed in the case of rigid piles and in the case of flexible piles with grid type of reinforcement. The load carrying capacity increased up to 33% in the case of geogrid reinforcement, and the differential settlement decreased around 35%, proving the efficiency of piled embankments with geogrid reinforcements. It is also shown that, using X-ray CT method and visualization techniques provides a better understanding of soil behavior in a reinforced embankment with the flexible pile foundation system.

  14. Management of Unruptured Intracranial Aneurysms.

    Science.gov (United States)

    Nasr, Deena M; Brown, Robert D

    2016-09-01

    Unruptured intracranial aneurysms (UIA) occur in approximately 2-3 % of the population. Most of these lesions are incidentally found, asymptomatic and typically carry a benign course. Although the risk of aneurysmal subarachnoid hemorrhage is low, this complication can result in significant morbidity and mortality, making assessment of this risk the cornerstone of UIA management. This article reviews important factors to consider when managing unruptured intracranial aneurysms including patient demographics, comorbidities, family history, symptom status, and aneurysm characteristics. It also addresses screening, monitoring, medical management and current surgical and endovascular therapies. PMID:27443382

  15. The effect of flow recirculation on abdominal aortic aneurysm

    Science.gov (United States)

    Taib, Ishkrizat; Amirnordin, Shahrin Hisham; Madon, Rais Hanizam; Mustafa, Norrizal; Osman, Kahar

    2012-06-01

    The presences of flow recirculation at the abdominal aortic aneurysm (AAA) region yield the unpredictable failure of aneurismal wall. The failure of the aneurismal wall is closely related to the hemodynamic factor. Hemodynamic factor such as pressure and velocity distribution play a significance role of aneurysm growth and rupture. By using the computational approach, the influence of hemodynamic factor is investigated using computational fluid dynamic (CFD) method on the virtual AAA model. The virtual 3D AAAs model was reconstructed from Spiral Computed Tomography scan (CT-scan). The blood flow is assumed as being transient, laminar and Newtonian within a rigid section of the vessel. The blood flow also driven by an imposed of pressure gradient in the form of physiological waveform. The pulsating blood flow is also considered in this simulation. The results on pressure distribution and velocity profile are analyzed to interpret the behaviour of flow recirculation. The results show the forming of vortices is seen at the aneurysm bulge. This vortices is form at the aneurysm region then destroyed rapidly by flow recirculation. Flow recirculation is point out much higher at distal end of aneurysm closed to iliac bifurcation. This phenomenon is managed to increase the possibility of aneurysm growth and rupture.

  16. Differential Sex Response to Aspirin in Decreasing Aneurysm Rupture in Humans and Mice.

    Science.gov (United States)

    Chalouhi, Nohra; Starke, Robert M; Correa, Tatiana; Jabbour, Pascal M; Zanaty, Mario; Brown, Robert D; Torner, James C; Hasan, David M

    2016-08-01

    We previously found that aspirin decreases the risk of cerebral aneurysm rupture in humans. We aim to assess whether a sex differential exists in the response of human cerebral aneurysms to aspirin and confirm these observations in a mouse model of cerebral aneurysm. A nested case-control analysis from the International Study of Unruptured Intracranial Aneurysms was performed to assess whether a sex differential exists in the response of human cerebral aneurysms to aspirin. A series of experiments were subsequently performed in a mouse model of cerebral aneurysms. Aneurysms were induced with hypertension and elastase injection into mice basal cisterns. We found that aspirin decreased the risk of aneurysm rupture more significantly in men than in women in the International Study of Unruptured Intracranial Aneurysms. In mice, aspirin and cyclooxygenase-2 inhibitor did not affect cerebral aneurysm formation but significantly decreased the incidence of rupture. The incidence of rupture was significantly lower in male versus female mice on aspirin. Gene expression analysis from cerebral arteries showed higher 15-hydroxyprostaglandin dehydrogenase levels in male mice. The rate of cerebral aneurysm rupture was similar in male mice receiving aspirin and 15-hydroxyprostaglandin dehydrogenase inhibitor compared with females receiving aspirin and 15-hydroxyprostaglandin dehydrogenase agonist, signaling a reversal of the sex-differential response to aspirin. Aspirin decreases aneurysm rupture in human and mice, in part through cyclooxygenase-2 pathways. Evidence from animal and human studies suggests a consistent differential effect by sex. 15-Hydroxyprostaglandin dehydrogenase activation in females reduces the incidence of rupture and eliminates the sex-differential response to aspirin. PMID:27296993

  17. Fluid-structure interaction of a patient-specific abdominal aortic aneurysm treated with an endovascular stent-graft.

    LENUS (Irish Health Repository)

    Molony, David S

    2009-01-01

    BACKGROUND: Abdominal aortic aneurysms (AAA) are local dilatations of the infrarenal aorta. If left untreated they may rupture and lead to death. One form of treatment is the minimally invasive insertion of a stent-graft into the aneurysm. Despite this effective treatment aneurysms may occasionally continue to expand and this may eventually result in post-operative rupture of the aneurysm. Fluid-structure interaction (FSI) is a particularly useful tool for investigating aneurysm biomechanics as both the wall stresses and fluid forces can be examined. METHODS: Pre-op, Post-op and Follow-up models were reconstructed from CT scans of a single patient and FSI simulations were performed on each model. The FSI approach involved coupling Abaqus and Fluent via a third-party software - MpCCI. Aneurysm wall stress and compliance were investigated as well as the drag force acting on the stent-graft. RESULTS: Aneurysm wall stress was reduced from 0.38 MPa before surgery to a value of 0.03 MPa after insertion of the stent-graft. Higher stresses were seen in the aneurysm neck and iliac legs post-operatively. The compliance of the aneurysm was also reduced post-operatively. The peak Post-op axial drag force was found to be 4.85 N. This increased to 6.37 N in the Follow-up model. CONCLUSION: In a patient-specific case peak aneurysm wall stress was reduced by 92%. Such a reduction in aneurysm wall stress may lead to shrinkage of the aneurysm over time. Hence, post-operative stress patterns may help in determining the likelihood of aneurysm shrinkage post EVAR. Post-operative remodelling of the aneurysm may lead to increased drag forces.

  18. Fluid-structure interaction of a patient-specific abdominal aortic aneurysm treated with an endovascular stent-graft

    Directory of Open Access Journals (Sweden)

    McGloughlin Tim M

    2009-10-01

    Full Text Available Abstract Background Abdominal aortic aneurysms (AAA are local dilatations of the infrarenal aorta. If left untreated they may rupture and lead to death. One form of treatment is the minimally invasive insertion of a stent-graft into the aneurysm. Despite this effective treatment aneurysms may occasionally continue to expand and this may eventually result in post-operative rupture of the aneurysm. Fluid-structure interaction (FSI is a particularly useful tool for investigating aneurysm biomechanics as both the wall stresses and fluid forces can be examined. Methods Pre-op, Post-op and Follow-up models were reconstructed from CT scans of a single patient and FSI simulations were performed on each model. The FSI approach involved coupling Abaqus and Fluent via a third-party software - MpCCI. Aneurysm wall stress and compliance were investigated as well as the drag force acting on the stent-graft. Results Aneurysm wall stress was reduced from 0.38 MPa before surgery to a value of 0.03 MPa after insertion of the stent-graft. Higher stresses were seen in the aneurysm neck and iliac legs post-operatively. The compliance of the aneurysm was also reduced post-operatively. The peak Post-op axial drag force was found to be 4.85 N. This increased to 6.37 N in the Follow-up model. Conclusion In a patient-specific case peak aneurysm wall stress was reduced by 92%. Such a reduction in aneurysm wall stress may lead to shrinkage of the aneurysm over time. Hence, post-operative stress patterns may help in determining the likelihood of aneurysm shrinkage post EVAR. Post-operative remodelling of the aneurysm may lead to increased drag forces.

  19. Anterior cerebral artery aneurysm associated with multiple intracranial aneurysms and abdominal aorta aneurysm

    OpenAIRE

    Lee, Yunghwan; Min, Hyung Ki; Yoon, Sang Pil

    2013-01-01

    We found multiple aneurysms in the intracranial arteries and abdominal aorta of an 87-year-old Korean female cadaver, whose cause of death was reported as "cholangiocarcinoma." An abdominal aortic aneurysm was observed in the infrarenal aorta, where the inferior mesenteric artery arose. The intracranial aneurysms were found in the A3 segment of the anterior cerebral artery and at the bifurcation of the middle cerebral artery. This case provides an example of the very rare association of perip...

  20. Continuum analysis of common branching patterns in the human arch of the aorta.

    Science.gov (United States)

    Zamir, M; Sinclair, P

    1990-01-01

    A model is proposed for describing common variations in the arrangement of branches on the arch of the human aorta, and the model is used to analyze data from 123 human arches. The analysis allows the observed variations to fall freely along a continuous spectrum, rather than be confined to discrete categories as is commonly done at present. The results thus describe these variations in a more natural way and throw some new light on their likely source.

  1. Effects of segmentation on patient-specific numerical simulation of cerebral aneurysm hemodynamics

    Science.gov (United States)

    Venugopal, Prem; Schmitt, Holger; Duckwiler, Gary R.; Valentino, Daniel J.

    2006-03-01

    One of the factors affecting the accuracy of patient-specific, imaging-based computational hemodynamic studies is the accuracy of geometric models created from medical images. In the present study we have investigated as to how accurate the geometric models should be in the context of cerebral aneurysms in order to obtain an accurate reproduction of intra-aneurysmal hemodynamics in individual patients using numerical simulations. Computed tomography angiography (CTA) images obtained for a patient-specific anterior communicating artery (ACoA) aneurysm and a patient-specific middle cerebral artery (MCA) aneurysm were used to construct the geometric models. For each aneurysm, two models were created, one using a different threshold value for image segmentation than the other. The average distance between the models was about the size of one in-plane pixel. It was found that for the MCA aneurysm, the simulated pressure and shear stress distributions for the two models were entirely different while for the ACoA aneurysm the mean pressure distribution obtained for the two models were similar, but the shear stress distributions were completely different. These results indicate that accurate reproduction of intra-aneurysmal hemodynamics would require the geometric reconstruction from medical images to be highly accurate.

  2. CREATIVITY METHODS IN TEACHING THE ARCH-DESIGN STUDIO

    Directory of Open Access Journals (Sweden)

    EIGBEONAN Andrew B.

    2013-01-01

    Full Text Available The aim of this paper is to search and find methods of fostering creativity or ideas relating to creativity in teaching the arch-design studio. Teaching creativity through its methods will be making the students grounded in designing with creativity ideas and therefore we can have professionals that design and build with satisfaction, safety and complementary. It means we can have real buildings and places that satisfy our clients, the society and in harmony with the environment. Although there are similarities in the curricula of training architects all over the world, but educators go about it in their own convenient and suitable ways and styles. The ideas of creativity have been part of architecture from the onset, but are not deligently applied and also not formally incorporated in the curricula of training. The topic is also very relevant and timely as arch-educators and other stakeholders are of the opinion that something has to be done to improve the ways and methods of training architects, especially the teaching of the arch-design studio with regards to creativity. Through exploration of literature and interviews (physical and telephone call this paper finds methods of stimulating creativity ideas in the teaching of arch-design studio. Some of the methods of motivating creativity found in teaching the arch-design studio are: analogy, metaphors, biomimicry, brainstorming, attribute listing, mental map, TRIZ, restrictions, charrette, browsing, excursions, focus groups, other peoples viewpoints, using crazy ideas, using experts, visualizing a goal, working with dreams and images and giving students design tools such as drawings CAD and model making.

  3. CORRELATION BETWEEN DURATION OF BOTTLE-FEEDING AND DENTAL ARCH MEASUREMENT IN DECIDUOUS DENTITION

    OpenAIRE

    Meldo Mahniza; Retno Hayati; Sri Harini

    2015-01-01

    The purpose of this study was to observe the correlation between duration of bottle feeding and dental arch measurement in deciduous dentition. Duration of bottle feeding was divided into 4 groups: ≤ 24 months, 25 – 36 months, 37 – 48 months, and > 48 months. The subjects were 120 kindergarten pupils, aged 3 – 5 years old. Measurements was done on the models of maxilla and mandible with digital caliper for the width and length of dental arch and using flexible curve for dental arch circumf...

  4. The Role of Arch Compression and Metatarsophalangeal Joint Dynamics in Modulating Plantar Fascia Strain in Running.

    Directory of Open Access Journals (Sweden)

    Kirsty A McDonald

    Full Text Available Elastic energy returned from passive-elastic structures of the lower limb is fundamental in lowering the mechanical demand on muscles during running. The purpose of this study was to investigate the two length-modulating mechanisms of the plantar fascia, namely medial longitudinal arch compression and metatarsophalangeal joint (MPJ excursion, and to determine how these mechanisms modulate strain, and thus elastic energy storage/return of the plantar fascia during running. Eighteen runners (9 forefoot and 9 rearfoot strike performed three treadmill running trials; unrestricted shod, shod with restricted arch compression (via an orthotic-style insert, and barefoot. Three-dimensional motion capture and ground reaction force data were used to calculate lower limb kinematics and kinetics including MPJ angles, moments, powers and work. Estimates of plantar fascia strain due to arch compression and MPJ excursion were derived using a geometric model of the arch and a subject-specific musculoskeletal model of the plantar fascia, respectively. The plantar fascia exhibited a typical elastic stretch-shortening cycle with the majority of strain generated via arch compression. This strategy was similar in fore- and rear-foot strike runners. Restricting arch compression, and hence the elastic-spring function of the arch, was not compensated for by an increase in MPJ-derived strain. In the second half of stance the plantar fascia was found to transfer energy between the MPJ (energy absorption and the arch (energy production during recoil. This previously unreported energy transfer mechanism reduces the strain required by the plantar fascia in generating useful positive mechanical work at the arch during running.

  5. The Role of Arch Compression and Metatarsophalangeal Joint Dynamics in Modulating Plantar Fascia Strain in Running.

    Science.gov (United States)

    McDonald, Kirsty A; Stearne, Sarah M; Alderson, Jacqueline A; North, Ian; Pires, Neville J; Rubenson, Jonas

    2016-01-01

    Elastic energy returned from passive-elastic structures of the lower limb is fundamental in lowering the mechanical demand on muscles during running. The purpose of this study was to investigate the two length-modulating mechanisms of the plantar fascia, namely medial longitudinal arch compression and metatarsophalangeal joint (MPJ) excursion, and to determine how these mechanisms modulate strain, and thus elastic energy storage/return of the plantar fascia during running. Eighteen runners (9 forefoot and 9 rearfoot strike) performed three treadmill running trials; unrestricted shod, shod with restricted arch compression (via an orthotic-style insert), and barefoot. Three-dimensional motion capture and ground reaction force data were used to calculate lower limb kinematics and kinetics including MPJ angles, moments, powers and work. Estimates of plantar fascia strain due to arch compression and MPJ excursion were derived using a geometric model of the arch and a subject-specific musculoskeletal model of the plantar fascia, respectively. The plantar fascia exhibited a typical elastic stretch-shortening cycle with the majority of strain generated via arch compression. This strategy was similar in fore- and rear-foot strike runners. Restricting arch compression, and hence the elastic-spring function of the arch, was not compensated for by an increase in MPJ-derived strain. In the second half of stance the plantar fascia was found to transfer energy between the MPJ (energy absorption) and the arch (energy production during recoil). This previously unreported energy transfer mechanism reduces the strain required by the plantar fascia in generating useful positive mechanical work at the arch during running.

  6. The 'Sphere': A Dedicated Bifurcation Aneurysm Flow-Diverter Device.

    Science.gov (United States)

    Peach, Thomas; Cornhill, J Frederick; Nguyen, Anh; Riina, Howard; Ventikos, Yiannis

    2014-01-01

    We present flow-based results from the early stage design cycle, based on computational modeling, of a prototype flow-diverter device, known as the 'Sphere', intended to treat bifurcation aneurysms of the cerebral vasculature. The device is available in a range of diameters and geometries and is constructed from a single loop of NITINOL(®) wire. The 'Sphere' reduces aneurysm inflow by means of a high-density, patterned, elliptical surface that partially occludes the aneurysm neck. The device is secured in the healthy parent vessel by two armatures in the shape of open loops, resulting in negligible disruption of parent or daughter vessel flow. The device is virtually deployed in six anatomically accurate bifurcation aneurysms: three located at the Basilar tip and three located at the terminus bifurcation of the Internal Carotid artery (at the meeting of the middle cerebral and anterior cerebral arteries). Both steady state and transient flow simulations reveal that the device presents with a range of aneurysm inflow reductions, with mean flow reductions falling in the range of 30.6-71.8% across the different geometries. A significant difference is noted between steady state and transient simulations in one geometry, where a zone of flow recirculation is not captured in the steady state simulation. Across all six aneurysms, the device reduces the WSS magnitude within the aneurysm sac, resulting in a hemodynamic environment closer to that of a healthy vessel. We conclude from extensive CFD analysis that the 'Sphere' device offers very significant levels of flow reduction in a number of anatomically accurate aneurysm sizes and locations, with many advantages compared to current clinical cylindrical flow-diverter designs. Analysis of the device's mechanical properties and deployability will follow in future publications.

  7. Aneurysm sac enlargement after endovascular Abdominal Aortic Aneurysm repair

    NARCIS (Netherlands)

    Dingemans, Siem A; Jonker, Frederik H W; Moll, Frans L; van Herwaarden, JA

    2015-01-01

    The aim of this study is to give an overview of current knowledge regarding abdominal aortic aneurysm (AAA) growth after endovascular aortic aneurysm repair (EVAR) that could potentially lead to aortic rupture. A search on Pubmed was performed. A total of 705 articles were found after initial search

  8. A critical role for proinflammatory behavior of smooth muscle cells in hemodynamic initiation of intracranial aneurysm.

    Directory of Open Access Journals (Sweden)

    Max Mandelbaum

    Full Text Available BACKGROUND: Intracranial aneurysm initiation is poorly understood, although hemodynamic insult is believed to play an important role in triggering the pathology. It has recently been found in a rabbit model that while macrophages are absent during hemodynamic aneurysm initiation, matrix metalloproteinases (MMPs are elevated and co-localize with smooth muscle cells (SMCs. This study investigates whether SMCs play a mechanistic role in aneurysm initiation triggered by hemodynamics. METHODS: Aneurysmal damage was induced at the basilar terminus via bilateral common carotid artery ligation in rabbits (n = 45, plus 7 sham controls. 16 ligated rabbits were treated with doxycycline to inhibit MMPs, 7 received clodronate liposomes to deplete circulating monocytes, and the rest received no drug. Effects of the treatments on aneurysm development were assessed histologically 5 days and 6 months after ligation. MMP production and expression of inflammatory markers by SMCs was monitored by immunohistochemistry and in situ hybridization. RESULTS: Treatment with doxycycline attenuated aneurysmal development examined at 5 days and 6 months, suggesting that MMPs contribute to aneurysm initiation. However, systemic depletion of macrophages did not decrease MMPs or suppress aneurysmal development. Immunofluorescence showed that during aneurysm initiation MMP-2 and MMP-9 were distributed in SMCs, and in situ hybridization indicated that they were transcribed by SMCs. In regions of early aneurysmal lesion, SMCs exhibited decreased expression of smooth muscle actin and increased NF-κB and MCP-1 expressions. CONCLUSIONS: During aneurysm initiation triggered by hemodynamics, SMCs rather than macrophages are responsible for MMP production that is critical for aneurysmal lesion development. These SMCs exhibit proinflammatory behavior.

  9. Inflammation and intracranial aneurysms: mechanisms of initiation, growth, and rupture

    Directory of Open Access Journals (Sweden)

    Peter S Amenta

    2015-06-01

    Full Text Available Outcomes following aneurysmal subarachnoid hemorrhage remain poor in many patients, despite advances in microsurgical and endovascular management. Consequently, considerable effort has been placed in determining the mechanisms of aneurysm formation, growth, and rupture. Various environmental and genetic factors are implicated as key components in the aneurysm pathogenesis. Currently, sufficient evidence exists to incriminate the inflammatory response as the common pathway leading to aneurysm generation and rupture. Central to this model is the interaction between the vessel wall and inflammatory cells. Dysfunction of the endothelium and vascular smooth muscle cells (VSMCs promotes a chronic pathological inflammatory response that progressively weakens the vessel wall. We review the literature pertaining to the cellular and chemical mechanisms of inflammation that contribute to aneurysm development. Hemodynamic stress and alterations in blood flow are discussed regarding their role in promoting chronic inflammation. Endothelial cell and VSMC dysfunction are examined concerning vascular remodeling. The contribution of inflammatory cytokines, especially tumor necrosis factor-α is illustrated. Inflammatory cell infiltration, particularly macrophage-mediated deterioration of vascular integrity, is reviewed. We discuss the inflammation as a means to determine aneurysms at greatest risk of rupture. Finally, future therapeutic implications of pharmacologic modulation of the inflammation are discussed.

  10. Pediatric intracranial aneurysms

    OpenAIRE

    Tripathy L; Singh S

    2009-01-01

    The incidence of subarachnoid haemorrhage from intracranial aneurysms in the paediatric age group is extremely rare. Interestingly, occurrence of vasospasm has been reported to be less in comparison to the adults. Both coiling and clipping have been advocated in selected cases. Because of the thinness of the wall of the arteries, utmost care should be taken while handling these arteries during surgery. The overall results of surgery in children have been reported to be better than their adult...

  11. 21 CFR 882.5200 - Aneurysm clip.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Aneurysm clip. 882.5200 Section 882.5200 Food and... NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5200 Aneurysm clip. (a) Identification. An aneurysm clip is a device used to occlude an intracranial aneurysm (a balloonlike sac formed on a blood...

  12. Experimental Study of Fluid Flow in an Aneurysm for Varying Shape Indices

    Science.gov (United States)

    Yu, Paulo; Choi, Cyrus; Durgesh, Vibhav

    2014-11-01

    An aneurysm is an abnormal bulging of a blood vessel wall. A ruptured aneurysm can be severely debilitating or fatal. There is a lack of understanding of fluid flow parameters leading to aneurysm growth and rupture. Clinical studies have shown that certain aneurysm shape indices are strongly correlated to rupture. The overall goal of this study is to comprehensively characterize fluid dynamics parameters inside an aneurysm sac, for varying shape indices. As part of this work, two different idealized aneurysm glass models are used, and an in-house flow loop system has been developed to simulate constant and physiological pressure gradients. Index of refraction matching techniques have been used for accurate estimation of fluid flow parameters. Laser Doppler Velocimetry measurements are conducted for Reynolds number values from 10-200 to understand impact of inflow conditions on flow structures and parameters inside aneurysm sac. Particle Image Velocimetry measurements are performed on several horizontal and vertical planes inside aneurysm sac and show the presence of secondary fluid structures inside the sac, not observed in mid-plane measurements from earlier studies. The results show dependence of flow parameters/structures on aneurysm shape and inflow conditions. This work is supported through the California State University Northridge Research Fellowship Program 2013-14.

  13. [Subarachnoid hemorrhage without aneurysm].

    Science.gov (United States)

    Müller-Forell, W; Welschehold, S; Köhler, J; Schicketanz, K H

    2002-11-01

    The rupture and bleeding of intracranial aneurysms is the most common cause of a spontaneous, non-traumatic subarachnoid hemorrhage (SAH). In up to 20% of these patients, no aneurysm is found, but the prognosis of these patients is known to be better than in those with aneurysms. The retrospective evaluation of the initial CT- and angiographic findings of 773 patients with spontaneous SAH, who underwent (up to three) 4-vessel DSA, brought a percentage of 12.4% with negative angiography. We found the favourable prognosis of these patients with negative angiography not only to be dependent from the distribution of the hemorrhage, with preference to perimesencephalic pattern, but the initial clinical state. 85% of our patients, who presented with perimesencephalic blood pattern and even 80% of those patients with additional intraventricular hemorrhage but the good clinical condition of Hunt-Hess I/II were discharged without neurological deficits. We recommend the obligatory 4-vessel catheter-angiography (DSA) in all patients with spontaneous SAH, independent of the blood pattern on initial CT, and one control in the presence of other than perimesencephalic subarachnoid hemorrhage, CTA might be reserved for additional controls. PMID:12458439

  14. ABDOMINAL AORTIC ANEURYSM (AAA

    Directory of Open Access Journals (Sweden)

    Rajesh G

    2011-11-01

    Full Text Available AAA is defined as a distension of the infrarenal aorta by more than 50% (or 1.5 times compared with a corresponding healthy, aged and gender matched population. AAA afflicts 1 to 6 % of the general population aged more than 60 years and the incidence rises by approximately 0.15% annually. When the definition of a maximum external diameter ≥3 cm is used, the prevalence of AAA is upto 6 times greater in men than in women. AAAs are much more common than thoracic aortic aneurysms. Most common cause of AAA is atherosclerosis (95%. Less common causes include infectious or inflammatory origin or those associated with connective tissue disorders. Process of AAA formation is multifactorial. Other than the general risk factors for atherosclerosis, genetic predispo s iti on, aut o immunity and hemodynamic factors all play roles in its formation. AAA is 1.5 times more frequent in hypert ensive patients. Smokers have 8 times risk for developing AAA. The existence of familial aggre gation of AAA implicates genetic factors in the etiology of AAA. Women with AAA are more likely to have a positive family history of this disorder. Those with a family history of AAA have an increased risk of 30%, and their aneurysms tend to occur at a younger age and carry a greater risk of rupture than do sporadic aneurysms.

  15. 基于Kriging模型的钢管混凝土连续梁拱桥有限元模型修正%CFST arch/continuous beam bridge FEM model updating based on Kriging model

    Institute of Scientific and Technical Information of China (English)

    胡俊亮; 颜全胜; 郑恒斌; 崔楠楠; 余晓琳

    2014-01-01

    A new method for FEM updating based on Kriging model was developed.The Kriging model is a linear unbiased minimum variance estimation to the unknown data in a region according to some characteristic information of region’s samples which have similar features with the unknown data.This method can obtain higher accuracy predicted results based on a small number of samples.Through a planar truss FEMupdating example,the feasibility and accuracy of the Kriging model were verified.And then the Kriging model was applied to a concrete-filled-steel-tubular (CFST)arch/continuous beam bridge FEM updating and the results were compared with those by the method of genetic algorithm (GA) combined with BP neural network.The analysis results show that the Kriging model needs only a certain amount of measured frequency data for FEM updating.There is no iterative calculation like in the FEM,which will exhaust much calculation time in updating program.This method can accurately predict the modal information outside the active frequency range.The results testify the high computational efficiency,accuracy and feasibility of the method applied in actual engineering.%提出基于Kriging模型的有限元模型修正方法。Kriging模型为据区域内若干信息样品某种特征数据对该区域同类特征未知数作线性无偏、最小方差估计方法,其只用少量样本即可获得较高精度预测结果。用Kriging模型对平面桁架进行有限元模型修正,验证该方法的可行性与准确性;对一连续梁拱桥进行模型修正,并与GA算法、BP神经网络方法模型修正结果比较分析。Kriging模型仅需一定量测量频率信息即可完成模型修正,能避免修正过程中进行有限元模型迭代计算。结果表明,该方法能准确预测有效频率范围(active frequency range)外模态信息,计算效率、精度较高,可用于工程实践。

  16. Developing a new endograft for the treatment of juxtarenal aortic aneurysms: definition and experimentation

    Directory of Open Access Journals (Sweden)

    Sergio Q. Belczak

    2015-06-01

    Full Text Available OBJECTIVES: To analyze angiotomographic parameters of juxtarenal aneurysms to assess the applicability of an endograft model to patients and to create in vitro and in vivo models to assess the new endograft. METHODS: A total of 49 patients with juxtarenal aneurysms were submitted to angiotomographic evaluation, and parameters such as the aortic diameter, the length of the neck, and the angulations of the celiac trunk, superior mesenteric artery and renal arteries; the distances between them; and anatomic variations were analyzed. Based on these parameters, an endograft model was developed and tested in a newly created in vitro model of juxtarenal aneurysm. An experimental model of juxtarenal aneurysm was then established in six pigs weighing 50-60 kg to assess the new endograft model. RESULTS: The angiotomographic parameters of juxtarenal aneurysm measured in this study were similar to those reported in the literature and allowed the development of an endograft based on the hourglass concept, which was applicable to 85.8% of the patients. The in vitro model of juxtarenal aneurysm evidenced good radiopacity and functionality and permitted adjustments in the new device and technical improvements in the procedures for treating these aneurysms. In addition, the porcine model of juxtarenal aneurysm was successfully created in all six animals using a bovine pericardial patch, and use of the new endograft in three pilot procedures evidenced its feasibility. CONCLUSIONS: The Hourglass endograft was rendered applicable to treatment of the majority of patients with juxtarenal aneurysms simply by changing its diameter. Moreover, the new in vitro and in vivo models were shown to be effective for assessing both the presented endograft and experiments assessing the endovascular treatment of juxtarenal aneurysms.

  17. Aortic Arch Vessel Anomalies Associated with Persistent Trigeminal Artery: (Report of a Case

    Directory of Open Access Journals (Sweden)

    M. Lotfi

    2008-01-01

    Full Text Available Introduction: Developmental anomalies of the aortic arch vessels are well described entities. Persistent trigeminal artery (PTA is the most common type of the four anomalous carotid-basilar anastomoses, and is due to abnormal persistence of what are normal transient communications between the embryonic forebrain and hindbrain arterial systems. Herein we report a previously undescribed variant consisting of coexistence of the PTA, truncus bicaroticus, and di-rect origin of left vertebral artery from aortic arch. "nCase Presentation: A 46 year-old man was admitted in the Namazi hospital with severe nausea, vomiting, severe headache, and decreased level of conscious-ness. Computed tomography scan revealed intraven-tricular hemorrhage with no evidence of subarach-noid hemorrhage. The patient was referred for four-vessel cerebral arteriography to evaluate the entire cerebral vascular anatomy. Arch aortography demon-strated the right subclavian artery as the first branch of the arch. The left vertebral artery arose directly from the arch as the second branch. The third branch consisted of a common trunk giving rise to the right and left common carotid arteries (Truncus Bicaroti-cus. The left subclavian artery arose as the final branch of the aortic arch. Selective angiography con-firmed that left vertebral artery did not arise from the left subclavian artery. Left vertebral artery angiogra-phy revealed a persistent trigeminal artery, with fill-ing of left internal carotid artery and its branches. No aneurysm or any other vascular abnormality was de-tected in this patient. The patient was subsequently managed by evacuation of IVH and ventriculostomy."nDiscussion: The usual configuration of three branches from the aortic arch is found in 60-80% of popula-tion. The left vertebral artery normally originate along the superior portion of the left subclavian ar-tery. However, this artery is subject to a number of variations; among all; the most common

  18. Tobacco smoking and aortic aneurysm

    DEFF Research Database (Denmark)

    Sode, Birgitte F; Nordestgaard, Børge G; Grønbæk, Morten;

    2012-01-01

    BACKGROUND: We determined the predictive power of tobacco smoking on aortic aneurysm as opposed to other risk factors in the general population. METHODS: We recorded tobacco smoking and other risk factors at baseline, and assessed hospitalization and death from aortic aneurysm in 15,072 individuals...... General Population Study, respectively. According to the magnitude of the hazard ratios, tobacco consumption was the most important risk factor for hospitalization and death from aortic aneurysm, followed by male sex and hypertension in both cohorts. The population attributable risk of aortic aneurysm...... outcomes due to tobacco consumption was 64% and 47% in the Copenhagen City Heart Study and Copenhagen General Population Study, respectively, and ranked highest among population attributable risks of aortic aneurysm in both cohorts. The absolute 10-year risk for hospitalization or death from aortic...

  19. True aneurysm of brachial artery.

    Science.gov (United States)

    Hudorović, Narcis; Lovričević, Ivo; Franjić, Dario Bjorn; Brkić, Petar; Tomas, Davor

    2010-10-01

    True upper extremity peripheral artery aneurysms are a rarely encountered arterial disorder. Following computer-tomography angiographic (CT-a) imaging examination, true saccular aneurysm, originating from the left brachial artery was diagnosed in the 77-year-old female without history of trauma. The aneurysm was resected by surgical intervention, and primary repair of the brachial artery was performed by interposition of a part of great saphenous vein harvested from the left groin and creation of two end-to-end anastomoses between interposition graft and previously resected part of brachial artery. No complication was observed during the follow-up. Surgical intervention for upper extremity aneurysms should be initiated without delay. Factors combined with minimal morbidity associated with repair suggest that surgical repair should be performed routinely for true upper extremity arterial aneurysms. PMID:20865459

  20. Correlation between maxillary central incisor crown morphology and mandibular dental arch form in normal occlusion subjects.

    Science.gov (United States)

    Paranhos, Luiz Renato; Lima, Carolina Souto; da Silva, Ricardo Henrique Alves; Daruge Júnior, Eduardo; Torres, Fernando Cesar

    2012-01-01

    The aim of this study was to evaluate the correlation between the morphology of the mandibular dental arch and the maxillary central incisor crown. Cast models from 51 Caucasian individuals, older than 15 years, with optimal occlusion, no previous orthodontic treatment, featuring 4 of the 6 keys to normal occlusion by Andrews (the first being mandatory) were observed. The models were digitalized using a 3D scanner, and images of the maxillary central incisor and mandibular dental arch were obtained. These were printed and placed in an album below pre-set models of arches and dental crowns, and distributed to 12 dental surgeons, who were asked to choose which shape was most in accordance with the models and crown presented. The Kappa test was performed to evaluate the concordance among evaluators while the chi-square test was used to verify the association between the dental arch and central incisor morphology, at a 5% significance level. The Kappa test showed moderate agreement among evaluators for both variables of this study, and the chi-square test showed no significant association between tooth shape and mandibular dental arch morphology. It may be concluded that the use of arch morphology as a diagnostic method to determine the shape of the maxillary central incisor is not appropriate. Further research is necessary to assess tooth shape using a stricter scientific basis. PMID:22666773

  1. Surgical Treatment of Aortic Aneurysm and Aortic Dissection:A Retrospective Analysis of 122 Cases

    Institute of Scientific and Technical Information of China (English)

    Tucheng SUN; Xionggang JIANG; Kailun ZHANG; Jie CAI; Shu CHEN; NYANGASSA B J; Zongquan SUN

    2009-01-01

    The study summarizes the clinical experience of surgical treatments of various types of thoracic aneurysm and aortic dissection.Clinical data of 122 patients with thoracic aneurysm and aortic dissection during July 2005 to July 2008 were retrospectively analyzed.The elective operations were performed in 107 patients while emergency surgery was done in 15 cases.Different surgical strategies were employed on the basis of diseased region,including simple ascending aortic replacement (n=3),aortic root replacement (n=43),hemi-arch replacement/total arch replacement + elephant trunk technique (n=32),thoracic/thoracoabdominal aortic replacement (n=8) and endovascular repair (n=36).In this series,there is 4 cases of perioperative death due to massive cerebral hemorrhage (n=1),respiratory failure (n=1) and multiple organ dysfunction syndrome (MODS) (n=2).Three cases developed post-operative massive cerebral infarction and the relatives of the patients abandoned treatment.Instant success rate of endovascular repair was 100%.The intimal rupture was sealed.Blood flow was unobstructed in true lumen and no false lumen was visualized.It was concluded that aggressive surgery should be considered in the patients with thoracic aneurysm and aortic dissection.Surgical procedures should vary with the location and the nature of the lesions.

  2. Endovascular treatment of thoracic aorta aneurysm and dissection

    International Nuclear Information System (INIS)

    Full text: The aim is to give up to date information about modern endovascular treatment of aortic pathology Dissection and aneurysms of the aorta are life threatening condition requiring in most of the cases prompt surgical or endovascular treatment because of the poor natural evolution. Purpose: to assess the immediate and 1-year outcome of endovascular treatment in broad spectrum of acute and subacute aortic syndrome during the last 3 years (November 2012 - August 2015) in City Clinic (Sofia, Bulgaria). We performed endovascular treatment of 47 patients (43 men, 4 women) at average age 54 y. with dissection (24) and aneurysms (23) of the aortic arch and thoracic aorta (in 5 emergent treatment was performed for aortic rupture). All patients were treated with minimal surgical femoral approach. In 4 (9%) of them initial carotid to carotid bypass was performed in order to provide a sufficient landing zone for the endograft implantation.the last 9 patients (19%) were treated without general anesthesia with either deep sedation or epidural anesthesia. Results: In all patients successful endograft implantation was achieved. Additional stent-graft or open cell stent was implanted in 4 cases in order to centralize the flow in the compressed true lumen. In 5 cases additional vascular plug or large coil was delivered in the left subclavian arteryostium in order to interrupt retrograde aneurysm or false lumen filling. Complications: 30 days mortality-2.2%, neurologic disorders (4.4%). one year survival- 45 (90.5%). 3 and 6 mo control CT scan showed no migration of the graft in 100%, full false lumen isolation in 19 out of 24 dissections (80%) and aneurysm free of expansion in 20 out of 23 (86%), patent carotid bay-pass graft in 4 of 4 (100%). This one center study showed excellent immediate and 1 year clinical and device results from endovascular repair of potentially fatal disease. Endovascular treatment is a method of choice for broad spectrum of aortic pathology

  3. Parallel multiscale simulations of a brain aneurysm

    Science.gov (United States)

    Grinberg, Leopold; Fedosov, Dmitry A.; Karniadakis, George Em

    2013-07-01

    Cardiovascular pathologies, such as a brain aneurysm, are affected by the global blood circulation as well as by the local microrheology. Hence, developing computational models for such cases requires the coupling of disparate spatial and temporal scales often governed by diverse mathematical descriptions, e.g., by partial differential equations (continuum) and ordinary differential equations for discrete particles (atomistic). However, interfacing atomistic-based with continuum-based domain discretizations is a challenging problem that requires both mathematical and computational advances. We present here a hybrid methodology that enabled us to perform the first multiscale simulations of platelet depositions on the wall of a brain aneurysm. The large scale flow features in the intracranial network are accurately resolved by using the high-order spectral element Navier-Stokes solver NɛκTαr. The blood rheology inside the aneurysm is modeled using a coarse-grained stochastic molecular dynamics approach (the dissipative particle dynamics method) implemented in the parallel code LAMMPS. The continuum and atomistic domains overlap with interface conditions provided by effective forces computed adaptively to ensure continuity of states across the interface boundary. A two-way interaction is allowed with the time-evolving boundary of the (deposited) platelet clusters tracked by an immersed boundary method. The corresponding heterogeneous solvers (NɛκTαr and LAMMPS) are linked together by a computational multilevel message passing interface that facilitates modularity and high parallel efficiency. Results of multiscale simulations of clot formation inside the aneurysm in a patient-specific arterial tree are presented. We also discuss the computational challenges involved and present scalability results of our coupled solver on up to 300 K computer processors. Validation of such coupled atomistic-continuum models is a main open issue that has to be addressed in future

  4. Parallel multiscale simulations of a brain aneurysm

    Energy Technology Data Exchange (ETDEWEB)

    Grinberg, Leopold [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States); Fedosov, Dmitry A. [Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, Jülich 52425 (Germany); Karniadakis, George Em, E-mail: george_karniadakis@brown.edu [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States)

    2013-07-01

    Cardiovascular pathologies, such as a brain aneurysm, are affected by the global blood circulation as well as by the local microrheology. Hence, developing computational models for such cases requires the coupling of disparate spatial and temporal scales often governed by diverse mathematical descriptions, e.g., by partial differential equations (continuum) and ordinary differential equations for discrete particles (atomistic). However, interfacing atomistic-based with continuum-based domain discretizations is a challenging problem that requires both mathematical and computational advances. We present here a hybrid methodology that enabled us to perform the first multiscale simulations of platelet depositions on the wall of a brain aneurysm. The large scale flow features in the intracranial network are accurately resolved by using the high-order spectral element Navier–Stokes solver NεκTαr. The blood rheology inside the aneurysm is modeled using a coarse-grained stochastic molecular dynamics approach (the dissipative particle dynamics method) implemented in the parallel code LAMMPS. The continuum and atomistic domains overlap with interface conditions provided by effective forces computed adaptively to ensure continuity of states across the interface boundary. A two-way interaction is allowed with the time-evolving boundary of the (deposited) platelet clusters tracked by an immersed boundary method. The corresponding heterogeneous solvers (NεκTαr and LAMMPS) are linked together by a computational multilevel message passing interface that facilitates modularity and high parallel efficiency. Results of multiscale simulations of clot formation inside the aneurysm in a patient-specific arterial tree are presented. We also discuss the computational challenges involved and present scalability results of our coupled solver on up to 300 K computer processors. Validation of such coupled atomistic-continuum models is a main open issue that has to be addressed in

  5. Determinant factors of Yemeni maxillary arch dimensions

    Directory of Open Access Journals (Sweden)

    Nabil Muhsen Al-Zubair

    2015-01-01

    Conclusion: Measurements of palatal depth and relationships of the canines to one another and to other teeth thus had the widest ranges, implying that these dimensions are the strongest determinants of maxillary arch size.

  6. 系杆拱桥吊杆节点足尺模型承载性能试验研究%Full-Scale Model Test Study of Load-Carrying Behavior of Hanger Joint of Tied Arch Bridge

    Institute of Scientific and Technical Information of China (English)

    桂水荣; 陈水生; 万水

    2013-01-01

    To study if the strength of the anchor head in anchorage zone of the hanger joint of tied arch bridge could meet the load-carrying requirements, the Shengmi Bridge in Nanchang was cited as an example, the full-scale model for the anchorage zone of the hanger joint at arch crown of the bridge was fabricated and the load-carrying capacity of the joint under the action of the de signed load was tested. The spatial finite element model of the anchorage zone was established and the theoretic values of the finite element and the measurement values of the test were comparatively analyzed. The results of the analysis show that the global strength of the double-layer steel socket of the hanger joint can meet the requirements, however, the local compressive strength values of the contact between the stiffening plates and the steel padding plate exceed the allowable values and the stiffening plates should be reinforced. The fabrication accuracy of the model has influence on the proportions of the load shared by the inner layer and outer layer of the steel socket and in the future tests of the similar kind, attention should be paid.%为研究系杆拱桥吊杆节点锚固区锚头强度是否满足受力要求,以南昌生米大桥为研究背景,制作拱顶吊杆节点锚固区的足尺模型,测试在设计荷载作用下吊杆节点承载力,并建立空间有限元模型,对比分析有限元理论值与试验实测值.研究结果表明:双层钢套筒整体强度满足要求,但加劲板与钢垫板接触位置局部抗压强度超过允许值,应对加劲板予以补强.模型试件的制作精度影响内钢管与外钢套筒分担荷载比例,在今后的类似试验过程中应予以重视.

  7. Changes in wall shear stresses in abdominal aortic aneurysms with increasing wall stiffness

    Science.gov (United States)

    Salsac, Anne-Virginie; Fernandez, Miguel

    2006-11-01

    During the growth of abdominal aortic aneurysms, local changes occur in the composition and structure of the diseased wall, resulting in its stiffening. A numerical simulation of the fluid structure interactions is performed in idealized models of aneurysms using a finite element method. A full coupling of the equations governing the pulsatile blood flow and the deformation of the compliant wall is undertaken. The effect of the progressive stiffening of the wall is analyzed at various stages in the growth of the aneurysm. Increasing the wall stiffness alters the distribution of wall shear stresses and leads to an increase in their magnitude. The wall compliance is shown to have a more pronounced effect on non-axisymmetric aneurysms, which sustain large displacements. The overall movement of the aneurysm models increases the three-dimensionality of the flow.

  8. Abdominal aortic aneurysm surgery

    DEFF Research Database (Denmark)

    Gefke, K; Schroeder, T V; Thisted, B;

    1994-01-01

    The goal of this study was to identify patients who need longer care in the ICU (more than 48 hours) following abdominal aortic aneurysm (AAA) surgery and to evaluate the influence of perioperative complications on short- and long-term survival and quality of life. AAA surgery was performed in 553......, 78% stated that their quality of life had improved or was unchanged after surgery and had resumed working. These data justify a therapeutically aggressive approach, including ICU therapy following AAA surgery, despite failure of one or more organ systems....

  9. Unoperated aortic aneurysm

    DEFF Research Database (Denmark)

    Perko, M J; Nørgaard, M; Herzog, T M;

    1995-01-01

    . No significant differences in survival for patients with dissecting and nondissecting AA were detected. In all, 132 patients (78%) died and 78 (59%) of them died of rupture. Mean time to rupture was 1,300 +/- 8 days. Cumulative 5-year hazard of rupture for the dissecting AA was twice that of the nondissecting (p......From 1984 to 1993, 1,053 patients were admitted with aortic aneurysm (AA) and 170 (15%) were not operated on. The most frequent reason for nonoperative management was presumed technical inoperability. Survivals for patients with thoracic, thoracoabdominal, and abdominal AA were comparable...

  10. Analysis of seismic disaster failure mechanism and dam-break simulation of high arch dam

    Science.gov (United States)

    Zhang, Jingkui; Zhang, Liaojun

    2014-06-01

    Based on a Chinese national high arch dam located in a meizoseismal region, a nonlinear numerical analysis model of the damage and failure process of a dam-foundation system is established by employing a 3-D deformable distinct element code (3DEC) and its re-development functions. The proposed analysis model considers the dam-foundation-reservoir coupling effect, influence of nonlinear contact in the opening and closing of the dam seam surface and abutment rock joints during strong earthquakes, and radiation damping of far field energy dissipation according to the actual workability state of an arch dam. A safety assessment method and safety evaluation criteria is developed to better understand the arch dam system disaster process from local damage to ultimate failure. The dynamic characteristics, disaster mechanism, limit bearing capacity and the entire failure process of a high arch dam under a strong earthquake are then analyzed. Further, the seismic safety of the arch dam is evaluated according to the proposed evaluation criteria and safety assessment method. As a result, some useful conclusions are obtained for some aspects of the disaster mechanism and failure process of an arch dam. The analysis method and conclusions may be useful in engineering practice.

  11. Techniques in Endovascular Aneurysm Repair

    Directory of Open Access Journals (Sweden)

    Sachin V. Phade

    2011-01-01

    Full Text Available Endovascular repair of infrarenal abdominal aortic aneurysms (EVARs has revolutionized the treatment of aortic aneurysms, with over half of elective abdominal aortic aneurysm repairs performed endoluminally each year. Since the first endografts were placed two decades ago, many changes have been made in graft design, operative technique, and management of complications. This paper summarizes modern endovascular grafts, considerations in preoperative planning, and EVAR techniques. Specific areas that are addressed include endograft selection, arterial access, sheath delivery, aortic branch management, graft deployment, intravascular ultrasonography, pressure sensors, management of endoleaks and compressed limbs, and exit strategies.

  12. [The role of intraoperative flowmetry in surgery of cerebral aneurysms].

    Science.gov (United States)

    Shekhtman, O D; Éliava, Sh Sh; Shakhnovich, V A; Pilipenko, Iu V

    2011-01-01

    Aim of the study was to assess the capabilities of intraoperative ultrasonic flowmetry in cerebral aneurysm surgery for prevention and immediate correction of cerebral ischemia. Ultrasonic flowmeter (Model HT313/323, "ransonic Systems Inc.", USA) was used during surgery in patients with complicated, large and giant aneurysms for evaluation of cerebral blood flow in main arteries (internal carotid, anterior and middle cerebral) and their branches (branches of M2-M3 and A2 segments). The series included 20 adult patients (13 male and 7 female) operated in Burdenko Moscow Neurosurgery Institute during 2008-2011 years. Mean age was 47.4 +/- 8.6 years. Giant aneurysms (> 2.5 cm) were present in 12 (60%) patients, large (1.5-2.5 cm)--in 5 (25%). Aneurysms of internal carotid artery were found in 8 cases. 1 female patient was operated on giant aneurysm of anterior cerebral--anterior communicating artery. In 4 (20%) cases significant alterations of blood flow were registered after clipping (> 25% according to initial), the changes were not visible. This allowed to correct the position of clips. In 2 surgeries ('low' paraclinoid aneurysms) the collateral flow was sufficient during temporary clipping, this allowed trapping of aneurysms with good neurological outcome. In 3 cases flowmeter was used to evaluate blood flow after extracranial-intracranial bypass. Ultrasonic flowmetry is a simple, reproducible and safe technique for intraoperative assessment of blood flow. Despite visual sufficiency of arteries flowmetry allows detection of surgically significant alterations of blood flow after clipping. PMID:22066255

  13. Arch Index: An Easier Approach for Arch Height (A Regression Analysis

    Directory of Open Access Journals (Sweden)

    Hironmoy Roy

    2012-04-01

    Full Text Available Background: Arch-height estimation though practiced usually in supine posture; is neither correct nor scientific as referred in literature, which favour for standing x-rays or arch-index as yardstick. In fact the standing x-rays can be excused for being troublesome in busy OPD, but an ink-footprint on simple graph-sheet can be documented, as it is easier, cheaper and requires almost no machineries and expertisation. Objective: So this study aimed to redefine the inter-relationship of the radiological standing arch-heights with the arch-index for correlation and regression so that from the later we can derive the radiographical standing arch-height values indirectly, avoiding the actual maneuver. Methods: The study involved 103 adult subjects attending at a tertiary care hospital of North Bengal. From the standing x-rays of foot, the standing navicular, talar heights were measured, and ‘normalised’ with the foot length. In parallel foot-prints also been obtained for arch-index. Finally variables analysed by SPSS software. Result: The arch-index showed significant negative correlations and simple linear regressions with standing navicular height, standing talar height as well as standing normalised navicular and talar heights analysed in both sexes separately with supporting mathematical equations. Conclusion: To measure the standing arch-height in a busy OPD, it is wise to have the foot-print first. Arch-index once get known, can be put in the equations as derived here, to predict the preferred standing arch-heights in either sex.

  14. Size-dependent bistability of an electrostatically actuated arch NEMS based on strain gradient theory

    International Nuclear Information System (INIS)

    This paper deals with the investigation of the size-dependent nature of nonlinear dynamics, in a doubly clamped shallow nano-arch actuated by spatially distributed electrostatic force. We employ strain gradient theory together with the Euler–Bernoulli and shallow arch assumptions in order to derive the nonlinear partial differential equation governing the transverse motion of the arch with mid-plane stretching effects. Using the Galerkin projection method, we derive the lumped single degree of freedom model which is then used for the study of the size effects on the nonlinear snap-through and pull-in instabilities of the arch nano-electro-mechanical-system (NEMS). Moreover, using strain gradient theory, the size-dependent bistability and fundamental frequencies of the nano-arch are scrutinized, revealing that, despite what is predicted by the classical theory, the bistability region in the parameter space of the nano-structure shrinks as the structure scales down. Also, we show that the minimum initial elevation, required for bistability, increases as the nano-arch scales down. (paper)

  15. Fast virtual stenting with deformable meshes: application to intracranial aneurysms.

    Science.gov (United States)

    Larrabide, Ignacio; Radaelli, Alessandro; Frangi, Alejandro

    2008-01-01

    Intracranial stents are medical devices that are becoming increasingly popular in the treatment of intracranial aneurysms. A methodology that predicts the released stent configuration prior to intervention has the potential to support the physician in the selection of the optimal approach for a specific patient. This paper proposes a fast virtual stenting technique based on constrained simplex deformable models that is able to virtually release stents in arbitrarily shaped vessel and aneurysm models. The technique effectively embeds the geometrical properties of the stent (cell design, strut size and shape and angles between struts) and achieves favorable execution times of the order of one minute.

  16. A Review of Diseases of Aortic Arch: Diagnosis by CTA

    Directory of Open Access Journals (Sweden)

    S. Sabouri

    2007-05-01

    Full Text Available The noninvasive revolution in cardiovascular imaging has altered the diagnostic algorithm for all types of acquired and congenital cardiovascular disease. CT techniques are commonly used in the diagnosis of aortic arch and its major branch vessels as well as thoracic and abdominal aortic diseases. CT angiogra-phy combines with CT scans obtained detailed in-formation on precise morphology and extent of dis-ease. Studies were performed on an MDCT unit (4row GE light speed. In infants and small children, the seda-tion rate for CT was lower than that used for patients of similar age undergoing cardiac MR imaging. Seda-tion times ranged between 5 and 10 min, in the pedi-atric population, MDCT was performed with a 1- to 2.5-mm slice thickness in adults, MDCT was per-formed with a 2.5-mm slice thickness with 50% re-construction overlap, pitch 0.75-1.CT angiographic studies were performed with nonionic contrast mate-rial with iodine concentrations of 300 mg/mL admin-istered at a dose of 2-3 mL/kg. Contrast material was injected by power injection, followed by normal sa-line, an automated bolus-tracking technique was used at an injection rate of 2-4 mL/sec. the bolus-tracking device was placed on the ascending aorta. For pa-tients with thoracic outlet syndrome, CT angiogram was performed with neutral position of arm and ab-duction of the arm. Radiologist studied the CT image data in an axial cine paging mode as well as multiplanar reformations. To plan effective management of Aorta disease, CTA is displayed using a combination of 3D images, such as those obtained by multiplanar reformation (MPR, curved planar reformation (CPR, maximum intensity projection (MIP and volume rendering (VR. Case reports include coarctation of aorta, vascular ring, right sided aorta, interrupted aortic arch, abber-ant vessels, paitent ductus arteriosus, subclavian steel syndrome, aneurysm, dissection, thoracic outlet syn-drome, arthritis and atherosclerotic stenosis.

  17. Dental Arch Dimension of Malay Ethnic Group

    Directory of Open Access Journals (Sweden)

    H. A. Mohammad

    2011-01-01

    Full Text Available Problem statement: Many previous studies tried to define and put specific measurements for dental arches dimension in different ethnics groups. However, these studies may be specific to an ethnic group and cannot always be applied to other ethnic types. The aim of this study: is to obtain specific dental arch dimensions for Malaysian Malay ethnic groups and compare between both genders. Approach: Involved clinical examination, collection and analysis of 60 dental cast of Malaysian Malay subjects from pure ethnic group (30 males and 30 females, 20-24 years old. All dental landmarks were located and determined and subsequently measurements had been done according to specific points have been selected. Statistical analysis were done using t-test. Results: Dental arch dimension were established in normal occlusion for Malaysian Malay ethnic group in this study. No significant difference was observed in arch dimensions between male and female of Malaysian Malay. Conclusion: These measurement should be considered during treatment, especially in prosthodontics and orthodontics where arch dimension can be modified appreciably.

  18. MATHEMATICAL ANALYSIS OF DENTAL ARCH OF CHILDREN IN NORMAL OCCLUSION: A LITERATURE REVIEW

    Directory of Open Access Journals (Sweden)

    M. Abu-Hussein DDS, MScD, MSc, DPD

    2012-03-01

    Full Text Available AIM. This paper is an attempt to compare and analyze the various mathematical models for defining the dental arch curvature of children in normal occlusion based upon a review of available literature. Background. While various studies have touched upon ways to cure or prevent dental diseases and upon surgical ways for teeth reconstitution to correct teeth anomalies during childhood, a substantial literature also exists, attempting to mathematically define the dental arch of children in normal occlusion. This paper reviews these dental studies and compares them analytically. Method. The paper compares the different mathematical approaches, highlights the basic assumptions behind each model, underscores the relevancy and applicability of the same, and also lists applicable mathematical formulae. Results. Each model has been found applicable to specific research conditions, as a universal mathematical model for describing the human dental arch still eludes satisfactory definition. The models necessarily need to include the features of the dental arch, such as shape, spacing between teeth and symmetry or asymmetry, but they also need substantial improvement. Conclusions. While the paper shows that the existing models are inadequate in properly defining the human dental arch, it also acknowledges that future research based on modern imaging techniques and computeraided simulation could well succeed in deriving an allinclusive definition for the human dental curve till now eluding the experts.

  19. Cluster headache and intracranial aneurysm

    OpenAIRE

    Valença, Marcelo Moraes; Andrade-Valença, Luciana P. A.; Martins, Carolina; de Aragão, Maria Fátima Vasco; Batista, Laécio Leitão; Peres, Mario Fernando Prieto; da Silva, Wilson Farias

    2007-01-01

    In the present study we describe the cases of two patients with cluster-like headache related to intracranial carotid artery aneurysm. One of these patients responded to verapamil prescription with headache resolution. In both cases the surgical clipping of the aneurysm resolved the cluster pain. These findings strongly suggest a pathophysiological link between the two conditions. The authors discuss the potential pathophysiological mechanisms underlying cluster-like headache due to intracran...

  20. Surgical Management of Ascending Aortic Aneurysm and Its Complications

    Directory of Open Access Journals (Sweden)

    Sisira Sran

    2014-01-01

    Full Text Available Ascending aortic aneurysms involving the proximal aortic arch, arising anywhere from the aortic valve to the innominate artery, represent various problems in which open surgery is generally required. Surgical options include excision of the aortic pathology or wrapping the aneurysm shell with an aortic Dacron graft. Intervention using the latter method can lead to extravasation of blood along the suture lines resulting in continuous bleeding within the periprosthetic space. The Cabrol technique was developed as a method for decompression of postoperative leaks by the formation of a conduit system from the periprosthetic space to the right atrium. The coronary ostia are anastomosed to a second graft in an end-to-end fashion, which is then anastomosed to the ascending aortic conduit side to side. The native aorta is then sewn around the prosthesis, hereby creating a shunt to drain anastomotic leakage. This shunt reduces postsurgical risk of pseudoaneurysm formation and normally closes a few days following surgery. We discuss the case of a patient who underwent Cabrol’s variation and six months later was demonstrated to have a patent shunt.

  1. Simulation of Aorta Artery Aneurysms Using Active Electronic Circuit

    Directory of Open Access Journals (Sweden)

    Kamran Hassani

    2007-01-01

    Full Text Available The fusiform and saccular aneurysms in different aorta artery sections were studied using an electronic circuit of cardiovascular system. The geometrical model of each artery section including thoracic and abdominal were generated in accordance with original anatomical data. By increasing the rate of aneurysm in each studied section, the pressure drop were calculated using CFD method, furthermore the compliance variations due to aneurysms were determined by mathematical method. The equivalent electronic circuit was then used to study the effects of the pressure drops and compliance variations on whole cardiovascular system. The results of the simulation exhibited the features of the pathology, including hypertension, the increase of the pulse pressure with the rate of aneurysm and the large magnitude of back flow during systole. Finally, the obtained results were compared with relevant clinical data .We have concluded from the study that aorta aneurysms in both fusiform and saccular, especially at highest diameters, may be the most important determinant of the artery rapture and heart failure.

  2. Endovascular Aortic Aneurysm Repair with Chimney and Snorkel Grafts: Indications, Techniques and Results

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Rakesh P., E-mail: rpatel9@nhs.net [Northwick Park Hospital, Department of Vascular Radiology (United Kingdom); Katsargyris, Athanasios, E-mail: kthanassos@yahoo.com; Verhoeven, Eric L. G., E-mail: Eric.Verhoeven@klinikum-nuernberg.de [Klinikum Nuernberg, Department of Vascular and Endovascular Surgery (Germany); Adam, Donald J., E-mail: donald.adam@tiscali.co.uk [Heartlands Hospital, Department of Vascular Surgery (United Kingdom); Hardman, John A., E-mail: johnhardman@doctors.org.uk [Royal United Hospital Bath, Department of Vascular Radiology (United Kingdom)

    2013-12-15

    The chimney technique in endovascular aortic aneurysm repair (Ch-EVAR) involves placement of a stent or stent-graft parallel to the main aortic stent-graft to extend the proximal or distal sealing zone while maintaining side branch patency. Ch-EVAR can facilitate endovascular repair of juxtarenal and aortic arch pathology using available standard aortic stent-grafts, therefore, eliminating the manufacturing delays required for customised fenestrated and branched stent-grafts. Several case series have demonstrated the feasibility of Ch-EVAR both in acute and elective cases with good early results. This review discusses indications, technique, and the current available clinical data on Ch-EVAR.

  3. The unruptured intracranial aneurysm treatment score : A multidis ciplinary consensus

    NARCIS (Netherlands)

    Etminan, Nima; Brown, Robert D.; Beseoglu, Kerim; Juvela, Seppo; Raymond, Jean; Morita, Akio; Torner, James C.; Derdeyn, Colin P.; Raabe, Andreas; Mocco, J.; Korja, Miikka; Abdulazim, Amr; Amin-Hanjani, Sepideh; Salman, Rustam Al Shahi; Barrow, Daniel L.; Bederson, Joshua; Bonafe, Alain; Dumont, Aaron S.; Fiorella, David J.; Gruber, Andreas; Hankey, Graeme J.; Hasan, David M.; Hoh, Brian L.; Jabbour, Pascal; Kasuya, Hidetoshi; Kelly, Michael E.; Kirkpatrick, Peter J.; Knuckey, Neville; Koivisto, Timo; Krings, Timo; Lawton, Michael T.; Marotta, Thomas R.; Mayer, Stephan A.; Mee, Edward; Pereira, Vitor Mendes; Molyneux, Andrew; Morgan, Michael K.; Mori, Kentaro; Murayama, Yuichi; Nagahiro, Shinji; Nakayama, Naoki; Niemelä, Mika; Ogilvy, Christopher S.; Pierot, Laurent; Rabinstein, Alejandro A.; Roos, Yvo B W E M; Rinne, Jaakko; Rosenwasser, Robert H.; Ronkainen, Antti; Schaller, Karl; Seifert, Volker; Solomon, Robert A.; Spears, Julian; Steiger, Hans Jakob; Vergouwen, Mervyn D I; Wanke, Isabel; Wermer, Marieke J H; Wong, George K C; Wong, John H.; Zipfel, Gregory J.; Sander Connolly, E.; Steinmetz, Helmuth; Lanzino, Giuseppe; Pasqualin, Alberto; Rüfenacht, Daniel; Vajkoczy, Peter; McDougall, Cameron; Hänggi, Daniel; Leroux, Peter; Rinkel, Gabriel J E; Loch Macdonald, R.

    2015-01-01

    Objective: We endeavored to develop an unruptured intracranial aneurysm (UIA) treatment score (UIATS) model that includes and quantifies key factors involved in clinical decision-making in the management of UIAs and to assess agreement for this model among specialists in UIA management and research.

  4. Hemodynamic patterns of anterior communicating artery aneurysms: a possible association with rupture

    Science.gov (United States)

    Castro, Marcelo A.; Putman, Christopher M.; Cebral, Juan R.

    2007-03-01

    The aim of this study is to characterize the different flows present at anterior communicating artery (AcoA) aneurysms and investigate possible associations with rupture. For that purpose, patient-specific computational models of 26 AcoA aneurysms were constructed from 3D rotational angiography images. Bilateral images were acquired in 15 patients who had both A1 segments of the anterior cerebral arteries and models were created by fusing the reconstructed left and right arterial trees. Computational fluid dynamics simulations were performed under pulsatile flow conditions. Visualizations of the flow velocity pattern were created to classify the aneurysms into the following flow types: A) inflow from both A1 segments, B) flow jet in the parent artery splits into three secondary jets, one enters the aneurysm and the other two are directed to the A2 segments, C) the parent artery jet splits into two secondary jets, one is directed to one of the A2 segments and the other enters the aneurysm before being directed to the other A2 segment, and D) the parent artery jet enters the aneurysm before being directed towards the A2 segments. The maximum wall shear stress in the aneurysm at the systolic peak (MWSS) was calculated. Most aneurysms in group A were unruptured and had the lowest MWSS. Group B had the same number of unruptured and ruptured aneurysms, and a low MWSS. Groups C and D had high rupture ratios, being the average MWSS significantly higher in group C. Finally, it was found that the MWSS was higher for ruptured aneurysms of all flow types.

  5. Numerical simulations of the discontinuous progression of cerebral aneurysms based on fluid-structure interactions study

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Investigations into the characteristics of hemodynamics will provide a better understanding of the pathology of cerebral aneurysms for clinicians.In this work,a steady state discontinuous-growth model of the cerebral aneurysms was proposed.With the assumption of the fluid-structure interaction between the wall of blood vessel and blood,a fluid-structure coupling numerical simulation for this model was built using software ANSYS and CFX.The simulation results showed that as the aneurysm volume increased,a blood flow vortex came forth,the vortex region became asymptotically larger,and eddy density became gradually stronger in it.After the emergence of the vortex region,the blood flow in the vicinity of the downstream in the aneurysms volume turned into bifurcated flow,and the location of the flow bifurcated point was shifted with the aneurysm volume growing while directions of the shear stress applied to two sides of the bifurcated point were opposite.The Von Mises stress distribution along the wall of aneurysm volume decreased in the prior period and increased gradually in the later period.The maximum stress was in the neck of the volume and the minimum was on the distal end in the whole process of growth.It was shown that as the aneurysm increased the maximum deformation location of the aneurysm,vertical to the streamline,was transferred from the distal end of the aneurysm to its neck,then back to its distal end of the aneurysm again.

  6. Riolan动脉弓的MSCT血管成像表现%Imaging features of Riolan arch on MSCT angiography

    Institute of Scientific and Technical Information of China (English)

    逄利博; 廖伟; 高玉颖; 杨立

    2012-01-01

    Objective To investigate imaging manifestations of Riolan arch on MSCT angiography (MSCTA). Methods Six patients with Riolan arch were collected. Three males had hypertension atherosclerosis, while 3 females had suffered from Takayasu's arteritis. MSCTA was performed (with 16-slice CT scanner in 4 cases and 64-slice scanner in 2), and abdominal pathological changes of blood vessel were observed with VR, M1P and MPR. Results The calibers of Riolan arch of the 6 cases were 3. 5—10. 0 mm, with average of (6. 7 ± 0. 4) mm. Proximal occlusion of superior mesenteric artery (SMA) was found in 2 cases of abdominal aorta atherosclerotic lesions, while Riolan arch was detected between the distal part of SMA with inferior mesenteric artery (IMA). In one case of abdominal aorta atherosclerotic lesions accompanied by abdominal aortic aneurysm, Riolan arch and inosculation arch were found between SMA and IMA with celiac trunk. Proximal occlusion of IMA was noticed in one case, with IMA distal part formed Riolan arch connecting SMA. Among 3 cases with Takayasu arteritis, stenosis of SMA was showed in 2 cases, Riolan arch formed between SMA and IMA, while SMA, IMA formed inosculation arch with celiac trunk in 1 case. Conclusion MSCTA could show the structural information of Riolan arch between SMA and IMA. Circuitous and dilated arterial arch between SMA and IMA were the characteristics of Riolan arch. The appearance of Riolan arch prompted occlusions or stenosis of SMA or IMA, suggesting the compensatory alteration of intestinal canal blood supply.%目的 探讨MSCT血管成像(MSCTA) Riolan动脉弓的影像表现.方法 收集6例Riolan动脉弓病变患者,3例男性患者为高血压动脉粥样硬化性疾病,3例女性患者均为多发性大动脉炎.采用16层(4例)、64层(2层)螺旋CT扫描行腹部CTA检查,对病变血管行VR、MIP和MPR重建.结果 6例Riolan动脉弓血管直径为3.5~10.0 mm,平均(6.7±0.4)mm.3例腹主动脉粥样硬化性病变中,肠

  7. Clinical presentation of cerebral aneurysms

    International Nuclear Information System (INIS)

    Presentation of a cerebral aneurysm can be incidental, discovered at imaging obtained for unrelated causes, can occur in the occasion of imaging obtained for symptoms possibly or likely related to the presence of an unruptured aneurysm, or can occur with signs and symptoms at the time of aneurismal rupture. Most unruptured intracranial aneurysms are thought to be asymptomatic, or present with vague or non-specific symptoms like headache or dizziness. Isolated oculomotor nerve palsies, however, may typically indicate the presence of a posterior circulation aneurysm. Ruptured intracranial aneurysms are by far the most common cause of non-traumatic subarachnoid hemorrhage and represent a neurological emergency with potentially devastating consequences. Subarachnoid hemorrhage may be easily suspected in the presence of sudden and severe headache, vomiting, meningism signs, and/or altered mental status. However, failure to recognize milder and more ambiguous clinical pictures may result in a delayed or missed diagnosis. In this paper we will describe the clinical spectrum of unruptured and ruptured intracranial aneurysms by discussing both typical and uncommon clinical features emerging from the literature review. We will additionally provide the reader with descriptions of the underlying pathophysiologic mechanisms, and main diagnostic pitfalls

  8. Flow Diverters for Intracranial Aneurysms

    Directory of Open Access Journals (Sweden)

    Yazan J. Alderazi

    2014-01-01

    Full Text Available Flow diverters (pipeline embolization device, Silk flow diverter, and Surpass flow diverter have been developed to treat intracranial aneurysms. These endovascular devices are placed within the parent artery rather than the aneurysm sac. They take advantage of altering hemodynamics at the aneurysm/parent vessel interface, resulting in gradual thrombosis of the aneurysm occurring over time. Subsequent inflammatory response, healing, and endothelial growth shrink the aneurysm and reconstruct the parent artery lumen while preserving perforators and side branches in most cases. Flow diverters have already allowed treatment of previously untreatable wide neck and giant aneurysms. There are risks with flow diverters including in-stent thrombosis, perianeurysmal edema, distant and delayed hemorrhages, and perforator occlusions. Comparative efficacy and safety against other therapies are being studied in ongoing trials. Antiplatelet therapy is mandatory with flow diverters, which has highlighted the need for better evidence for monitoring and tailoring antiplatelet therapy. In this paper we review the devices, their uses, associated complications, evidence base, and ongoing studies.

  9. Clinical presentation of cerebral aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Cianfoni, Alessandro [Neurocentro della Svizzera Italiana, Ospedale Civico di Lugano, via Tesserete, 46, 6900 Lugano (Switzerland); Pravatà, Emanuele, E-mail: emanuele.pravata@gmail.com [Neurocentro della Svizzera Italiana, Ospedale Civico di Lugano, via Tesserete, 46, 6900 Lugano (Switzerland); De Blasi, Roberto [Neurocentro della Svizzera Italiana, Ospedale Civico di Lugano, via Tesserete, 46, 6900 Lugano (Switzerland); Tschuor, Costa Silvia [Dipartimento di Radiologia, Ospedale Civico di Lugano, via Tesserete, 46, 6900 Lugano (Switzerland); Bonaldi, Giuseppe [U.O. Neuroradiologia, Ospedali Riuniti di Bergamo, Largo Barozzi, 1, 24128 Bergamo (Italy)

    2013-10-01

    Presentation of a cerebral aneurysm can be incidental, discovered at imaging obtained for unrelated causes, can occur in the occasion of imaging obtained for symptoms possibly or likely related to the presence of an unruptured aneurysm, or can occur with signs and symptoms at the time of aneurismal rupture. Most unruptured intracranial aneurysms are thought to be asymptomatic, or present with vague or non-specific symptoms like headache or dizziness. Isolated oculomotor nerve palsies, however, may typically indicate the presence of a posterior circulation aneurysm. Ruptured intracranial aneurysms are by far the most common cause of non-traumatic subarachnoid hemorrhage and represent a neurological emergency with potentially devastating consequences. Subarachnoid hemorrhage may be easily suspected in the presence of sudden and severe headache, vomiting, meningism signs, and/or altered mental status. However, failure to recognize milder and more ambiguous clinical pictures may result in a delayed or missed diagnosis. In this paper we will describe the clinical spectrum of unruptured and ruptured intracranial aneurysms by discussing both typical and uncommon clinical features emerging from the literature review. We will additionally provide the reader with descriptions of the underlying pathophysiologic mechanisms, and main diagnostic pitfalls.

  10. ARCHES: Advancing Research & Capacity in Hydrologic Education and Science

    Science.gov (United States)

    Milewski, A.; Fryar, A. E.; Durham, M. C.; Schroeder, P.; Agouridis, C.; Hanley, C.; Rotz, R. R.

    2013-12-01

    Educating young scientists and building capacity on a global scale is pivotal towards better understanding and managing our water resources. Based on this premise the ARCHES (Advancing Research & Capacity in Hydrologic Education and Science) program has been established. This abstract provides an overview of the program, links to access information, and describes the activities and outcomes of student participants from the Middle East and North Africa. The ARCHES program (http://arches.wrrs.uga.edu) is an integrated hydrologic education approach using online courses, field programs, and various hands-on workshops. The program aims to enable young scientists to effectively perform the high level research that will ultimately improve quality of life, enhance science-based decision making, and facilitate collaboration. Three broad, interlinked sets of activities are incorporated into the ARCHES program: (A1) the development of technical expertise, (A2) the development of professional contacts and skills, and (A3) outreach and long-term sustainability. The development of technical expertise (A1) is implemented through three progressive instructional sections. Section 1: Students were guided through a series of online lectures and exercises (Moodle: http://wrrs.uga.edu/moodle) covering three main topics (Remote Sensing, GIS, and Hydrologic Modeling). Section 2: Students participated in a hands-on workshop hosted at the University of Georgia's Water Resources and Remote Sensing Laboratory (WRRSL). Using ENVI, ArcGIS, and ArcSWAT, students completed a series of lectures and real-world applications (e.g., Development of Hydrologic Models). Section 3: Students participated in field studies (e.g., measurements of infiltration, recharge, streamflow, and water-quality parameters) conducted by U.S. partners and international collaborators in the participating countries. The development of professional contacts and skills (A2) was achieved through the promotion of networking

  11. Risk factors for intracranial aneurysm in a Chinese ethnic population

    Institute of Scientific and Technical Information of China (English)

    GU Yu-xiang; CHEN Xian-cheng; SONG Dong-lei; LENG Bing; ZHAO Fan

    2006-01-01

    Background Intracranial aneurysm (IAN) is a protruding bubble or a sac on a brain artery that balloons out over time, which may lead to spontaneous subarachnoid hemorrhage (SAH), ultimately disability and mortality.Current research indicates that the disease is due to multiple causes, including environmental factors and various congenital abnormalities of blood vessels. Apart from congenital predisposition, various high-risk factors such as sex, age, hypertension, and atherosclerosis are involved in the formation of intracranial aneurysms. The aim of this study was to investigate the risk factors associated with the formation of sporadic intracranial aneurysms in Chinese Han ethnic patients.Methods A total of 251 patients with intracranial aneurysm and 338 patients with other cerebral diseases (control group) were enrolled in this study. Single factor and logistic regression model were used to analyze the association of intracranial aneurysms with age; sex; cigarette smoking; alcohol or cocaine consumption; history of hypertension, coronary artery disease, diabetes mellitus and inherited connective tissue disease; and the levels of fasting blood glucose and blood fat. The data expressed as mean ± standard deviation were processed with the statistical software SPSS13. Quantitative and qualitative data were analyzed by the independent-sample t test,and the chi-square test respectively. Logistic regression method was used to analyze the multiple factors.Results In the 251 patients, 163 (64.94%) were at age of 40 to 60 years. Sex (OR, 1.41; 95% CI, 1.01-1.96), cigarette smoking (OR, 1.81; 95% CI, 1.06-3.10), hypertension (OR, 2.32; 95% CI, 1.30-4.16) and fasting blood glucose were significantly associated with intracranial aneurysm (P<0.05). Intracranial aneurysm was correlated with alcohol consumption, coronary artery disease, and the level of blood lipids (P>0.05). Using logistic regression analysis, we identified female sex and advanced age as significant risk

  12. A canine juxtarenal abdominal aortic aneurysm model applying to endovascular stent-graft's and hemodynamic study%适用于腔内隔绝移植物及血流动力学研究的犬肾周型腹主动脉瘤模型的建立

    Institute of Scientific and Technical Information of China (English)

    黄志军; 陆清声; 景在平; 林晨; 廖明芳

    2012-01-01

    目的 建立一种适用于研究腔内隔绝移植物及血流动力学的犬肾周型腹主动脉瘤模型.方法 通过在犬近肾腹主动脉段移植经0.6%戊二醛浸泡30 min去抗原处理后的牛颈外静脉,制作15例犬肾周型腹主动脉瘤模型.将此动脉瘤模型与患者的肾周型腹主动脉瘤进行形态学的对比,并且检测血流动力学参数外与15例腹主动脉瘤患者对比.结果 15只动物手术过程顺利,术中死亡0只,术后1天腹腔出血死亡1只,术后2天急性肾衰死亡 3只.动物模型与肾周型腹主动脉瘤患者动脉瘤形态相似.直径、壁厚的比例相似.瘤体内收缩压、舒张压、平均动脉压均高于肾上腹主动脉、髂总功脉和动脉瘤入、出口.动脉壁弹性相似.动脉瘤中都出现了涡流或湍流.结论 此模型是适合肾周型腹主动脉瘤腔内隔绝移植物及血流动力学研究的有较大实用价值的动物模型.%Objective To construct an animal juxtarenal abdominal aortic aneurysm model applying to endovascular stent-graft' s and hemodynamic study. Methods The bovine jugular vein segments which had been treated with 0. 6% glutaral were removed to fifteen hybrid canines at juxtarenal abdominal aortic to construct aneurysms. The aneurysm models' hemodynamic data were selected and were contrasted with fifteen patients' juxtarenal abdominal aortic aneurysms. Results The operations of all fifteen canines were-successful. No canine died in the operation but 1 canine died 1 day after operation because of abdominal bleeding and three died in two days because of acute renal failure. The models were similar to the patients in such area as the configuration of aneurysm, the proportion of aneurysm's diameter to wall's thickness, the elasticity of aneurysm's wall and the blood flow in aneurysm. Like the patients, the systolic, diastolic and mean pressures in the aneurysm of the model were higher than the pressures in the suprarenal aorta, the common

  13. Intracranial aneurysm associated with relapsing polychondritis

    Energy Technology Data Exchange (ETDEWEB)

    Coumbaras, M.; Boulin, A.; Pierot, L. [Dept. of Neuroradiology, Hopital Foch, Suresnes (France); Piette, A.M.; Bletry, O. [Dept. of Medicine, Hopital Foch, Suresnes (France); Graveleau, P. [Dept. of Neurology, Hopital Foch, Suresnes (France)

    2001-07-01

    We describe a 50-year-old man with relapsing polychondritis (RP) involving auricular cartilage, uveitis and hearing loss, who had an aneurysm of the anterior cerebral artery. Intracranial aneurysm is a rare manifestation of RP. (orig.)

  14. Aortic aneurysm secondary to umbilical artery catheterization

    International Nuclear Information System (INIS)

    A 14-month-girl presented with an asymptomatic posterior mediastinal mass. She had a history of prematurity, umbilical artery catheterization, and sepsis. The diagnosis of aortic aneurysm was made by dynamic computed tomography. The aneurysm was successfully resected. (orig.)

  15. Aneurysms - Multiple Languages: MedlinePlus

    Science.gov (United States)

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Aneurysms URL of this page: https://medlineplus.gov/languages/aneurysms.html Other topics A-Z A B ...

  16. Brain Aneurysm: Early Detection and Screening

    Science.gov (United States)

    ... and Screening A- A A+ Early Detection and Screening Brain aneurysms can be similar to heart attacks. ... aneurysm is about to rupture. Fortunately, through imaging screening techniques, individuals at high risk of harboring a ...

  17. Study on Optimal Grouting Timing for Controlling Uplift Deformation of a Super High Arch Dam

    Science.gov (United States)

    Lin, Peng; Zhu, Xiaoxu; Li, Qingbin; Liu, Hongyuan; Yu, Yongjun

    2016-01-01

    A grouting model is developed for use during the grouting of the complex foundation of a super high arch dam. The purpose as to determine the optimal grouting timing and appropriate grouting pressure involved in controlling the uplift deformation of the dam. The model determines the optimal grouting time as the height of the arch dam increases with the concrete pouring, by checking the tensile stresses in the dam against standard specifications. The appropriate grouting pressures are given on the basis of the actual grouting pressures monitored during the upstream riverbed foundation grouting. An engineering procedure, applying the model, was then proposed and used during foundation grouting under the toe block of the Xiluodu super high-arch dam in south-western China. The quality of the foundation grouting was evaluated against the results from pressurized water permeability tests, acoustic wave velocity tests, elastic modulus tests and panoramic photographing of the rockmass on completion of the foundation grouting. The results indicated that the proposed grouting model can be applied to effectively reduce the uplift deformation and associated cracking risk for super high arch dams, and it can be concluded that the proposed engineering grouting procedure is a valuable tool for improving foundation grouting under the toe blocks of a super high arch dam.

  18. Surveillance intervals for small abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Bown, Matthew J; Sweeting, Michael J; Brown, Louise C;

    2013-01-01

    Small abdominal aortic aneurysms (AAAs [3.0 cm-5.4 cm in diameter]) are monitored by ultrasound surveillance. The intervals between surveillance scans should be chosen to detect an expanding aneurysm prior to rupture.......Small abdominal aortic aneurysms (AAAs [3.0 cm-5.4 cm in diameter]) are monitored by ultrasound surveillance. The intervals between surveillance scans should be chosen to detect an expanding aneurysm prior to rupture....

  19. Hygroma following endovascular femoral aneurysm exclusion

    DEFF Research Database (Denmark)

    Wad, Morten; Pedersen, Brian Lindegaard; Lönn, Lars;

    2013-01-01

    Endovascular treatment of aneurysms in the superficial femoral artery (SFA) and popliteal segments is a suggested alternative to open surgical repair. Careful selection of patients for endovascular treatment of SFA aneurysms is mandatory.......Endovascular treatment of aneurysms in the superficial femoral artery (SFA) and popliteal segments is a suggested alternative to open surgical repair. Careful selection of patients for endovascular treatment of SFA aneurysms is mandatory....

  20. Study on hemodynamics in patient-specific thoracic aortic aneurysm

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The objective of this study is to investigate the hemodynamics in patient-specific thoracic aortic aneurysm and discuss the reason for formation of aortic plaque.A 3-Dimensional pulsatile blood flow in thoracic aorta with a fusiform aneurysm and 3 main branched vessels was studied numerically with the average Reynolds number of 1399 and the Womersley number of 19.2.Based on the clinical 2-Dimensional CT slice data,the patient-specific geometry model was constructed using medical image process software.Un...

  1. Complex pathologies of angiotensin Ⅱ-induced abdominal aortic aneurysms

    Institute of Scientific and Technical Information of China (English)

    Alan DAUGHERTY; Lisa A. CASSIS; Hong LU

    2011-01-01

    Angiotensin Ⅱ (Angll) is the primary bioactive peptide of the renin angiotensin system that plays a critical role in many cardiovascular diseases.Subcutaneous infusion of Angll into mice induces the development of abdominal aortic aneurysms (AAAs).Like human AAAs,Angll-induced AAA tissues exhibit progressive changes and considerable heterogeneity.This complex pathology provides an impediment to the quantification of aneurysmal tissue composition by biochemical and immunostaining techniques.Therefore,while the mouse model of Angll-induced AAAs provides a salutary approach to studying the mechanisms of the evolution of AAAs in humans,meaningful interpretation of mechanisms requires consideration of the heterogeneous nature of the diseased tissue.

  2. Basic fibroblast growth factor gene transfection in repair of internal carotid artery aneurysm wall

    Institute of Scientific and Technical Information of China (English)

    Lei Jiao; Ming Jiang; Jinghai Fang; Yinsheng Deng; Zejun Chen; Min Wu

    2012-01-01

    Surgery or interventional therapy has some risks in the treatment of cerebral aneurysm. We established an internal carotid artery aneurysm model by dripping elastase in the crotch of the right internal and external carotid arteries of New Zealand rabbits. Following model induction, lentivirus carrying basic fibroblast growth factor was injected through the ear vein. We found that the longer the action time of the lentivirus, the smaller the aneurysm volume. Moreover, platelet-derived growth factor expression in the aneurysm increased, but smooth muscle 22 alpha and hypertension-related gene 1 mRNA expression decreased. At 1, 2, 3, and 4 weeks following model establishment, following 1 week of injection of lentivirus carrying basic fibroblast growth factor, the later the intervention time, the more severe the blood vessel damage, and the bigger the aneurysm volume, the lower the smooth muscle 22 alpha and hypertension-related gene 1 mRNA expression. Simultaneously, platelet-derived growth factor expression decreased. These data suggest that recombinant lentivirus carrying basic fibroblast growth factor can repair damaged cells in the aneurysmal wall and inhibit aneurysm dynamic growth, and that the effect is dependent on therapeutic duration.

  3. [Albert Einstein and his abdominal aortic aneurysm].

    Science.gov (United States)

    Cervantes Castro, Jorge

    2011-01-01

    The interesting case of Albert Einstein's abdominal aortic aneurysm is presented. He was operated on at age 69 and, finding that the large aneurysm could not be removed, the surgeon elected to wrap it with cellophane to prevent its growth. However, seven years later the aneurysm ruptured and caused the death of the famous scientist.

  4. Structure and distribution of arches in shaken hard sphere deposits

    OpenAIRE

    Pugnaloni, Luis A.; Barker, G. C.

    2003-01-01

    We investigate the structure and distribution of arches formed by spherical, hard particles shaken in an external field after they come to rest. Arches (or bridges) are formed during a computer-simulated, non-sequential deposition of the spheres after each shaking cycle. We identify these arches by means of a connectivity criterion and study their structural characteristics and spatial distribution. We find that neither the size distribution nor the shape of the arches is strongly affected by...

  5. Isogeometric analysis: a powerful numerical tool for the elastic analysis of historical masonry arches

    Science.gov (United States)

    Cazzani, Antonio; Malagù, Marcello; Turco, Emilio

    2016-03-01

    We illustrate a numerical tool for analyzing plane arches such as those frequently used in historical masonry heritage. It is based on a refined elastic mechanical model derived from the isogeometric approach. In particular, geometry and displacements are modeled by means of non-uniform rational B-splines. After a brief introduction, outlining the basic assumptions of this approach and the corresponding modeling choices, several numerical applications to arches, which are typical of masonry structures, show the performance of this novel technique. These are discussed in detail to emphasize the advantage and potential developments of isogeometric analysis in the field of structural analysis of historical masonry buildings with complex geometries.

  6. Assembly and lifting of Pearl-Chain arches

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Viebæk, N.E.;

    2015-01-01

    Pearl-Chain arches were invented at the Technical University of Denmark in cooporation with the company Abeo A/S. The system uses specially designed, pre-fabricated concrete elements that are post-tensioned together into an arch shape, which is then lifted into place. The arches can be used both ...

  7. Numerical simulation of damage in high arch dam due to earthquake

    Institute of Scientific and Technical Information of China (English)

    Hong ZHONG; Gao LIN; Hongjun LI

    2009-01-01

    Based on the assumption that concrete is macroscopic homogeneous, the cracking evolution process and damage mode of high arch dams are studied in consideration of the heterogeneity of concrete in mesos-cale. The bilinear damage evolution model and the damage evolution model expressed in power function with descending section are adopted to combine with the Mohr-Coulomb criterion with tension cut-off to investigate the crack development and fracture mode of high arch dams under the action of an earthquake. The analysis result of a high arch dam in China under design shows that cracks that take place in concrete are caused by excessive tensile stress. The cracks initiate at the middle of the dam top and distribute at the upper half of the dam while the rest of the parts remain intact. This conclusion agrees with the model test result.

  8. Research of air-cushion isolation effects on high arch dam reservoir

    Institute of Scientific and Technical Information of China (English)

    Shao-Jie Zhang; Jiang Chen; Yuan-Ze Zhang; Hao-Wu Liu

    2011-01-01

    A three-dimensional (3D) finite element model of air-cushion isolated arch dam is presented with the nonlinear gas-liquid-solid multi-field dynamic coupling effect taken into account.In this model,the displacement formulation in Lagrange method,pressure formulation in Euler method,nonlinear contact model based on Coulomb friction law are applied to the air-cushion,reservoir and contraction joint domain,respectively.The dynamic response of Jinping I arch dam with a height of 305m is analyzed using the seismic records of the Wenchuan Earthquake in 2008.Numerical resuits show that the air-cushion isolation reduces significantly the hydrodynamic pressure as well as the opening width for the contraction joints of high arch dam.

  9. Precast Pearl-Chain concrete arch bridges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2015-01-01

    A Pearl-Chain Bridge is a closed-spandrel arch bridge consisting of a number of straight pre-fabricated so called Super-Light Deck elements put together in an arch shape by post-tensioning cables. Several Pearl-Chain arches can be positioned adjacent to each other by a crane to achieve a bridge...... the technology was used. We also study other important components and details in the Pearl-Chain Bridge concept and review the effects of different types of loads. A theoretical case study of a circular 30 m span Pearl-Chain Bridge is presented showing the influence of a number of parameters: The number of post......-tensioning cables, the rise to span ratio, the height of the filling, and the height of the Super-Light Decks. We find that Pearl-Chain Bridges can be adjusted to resist specific moment loads by changing the normal force in the arch cross section by altering the above parameters. It is also found that the negative...

  10. Arch Coal focuses on its future

    International Nuclear Information System (INIS)

    Arch Coal, Inc (ACI) has emerged as the second largest US coal producer, with nearly 5000 employees producing 110 million tons of coal per year. The article discusses the company's philosophy, as stated by Steve Leer, President and CEO, and reports interviews with six other senior executives talking about policy on finances, sales, marketing, business development and operations. 8 photos

  11. Neurofibromin Deficient Myeloid Cells are Critical Mediators of Aneurysm Formation In Vivo

    Science.gov (United States)

    Li, Fang; Downing, Brandon D.; Smiley, Lucy C.; Mund, Julie A.; DiStasi, Matthew R.; Bessler, Waylan K.; Sarchet, Kara N.; Hinds, Daniel M.; Kamendulis, Lisa M.; Hingtgen, Cynthia M.; Case, Jamie; Clapp, D. Wade; Conway, Simon J.; Stansfield, Brian K.; Ingram, David A.

    2014-01-01

    Background Neurofibromatosis Type 1 (NF1) is a genetic disorder resulting from mutations in the NF1 tumor suppressor gene. Neurofibromin, the protein product of NF1, functions as a negative regulator of Ras activity in circulating hematopoietic and vascular wall cells, which are critical for maintaining vessel wall homeostasis. NF1 patients have evidence of chronic inflammation resulting in development of premature cardiovascular disease, including arterial aneurysms, which may manifest as sudden death. However, the molecular pathogenesis of NF1 aneurysm formation is unknown. Method and Results Utilizing an angiotensin II-induced aneurysm model, we demonstrate that heterozygous inactivation of Nf1 (Nf1+/−) enhanced aneurysm formation with myeloid cell infiltration and increased oxidative stress in the vessel wall. Using lineage-restricted transgenic mice, we show loss of a single Nf1 allele in myeloid cells is sufficient to recapitulate the Nf1+/− aneurysm phenotype in vivo. Finally, oral administration of simvastatin or the antioxidant apocynin, reduced aneurysm formation in Nf1+/− mice. Conclusion These data provide genetic and pharmacologic evidence that Nf1+/− myeloid cells are the cellular triggers for aneurysm formation in a novel model of NF1 vasculopathy and provide a potential therapeutic target. PMID:24370551

  12. A failure of matrix metalloproteinase inhibition in the prevention of rat intracranial aneurysm formation

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, T.J.; Kallmes, D.F. [Mayo Clinic and Foundation, Department of Radiology, Rochester, MN (United States); Marx, W.F. [Asheville Radiology Associates, Asheville, NC (United States)

    2006-03-15

    We tested the hypothesis that nonspecific matrix metalloproteinase (MMP) inhibition with doxycycline would decrease the incidence of intracranial aneurysm formation in a rat aneurysm model. We performed common carotid artery ligation on 96 Long-Evans rats. A treatment group of 48 animals was chosen at random to receive oral doxycycline (3 mg/kg) in addition to standard rat chow, and the control group of 48 animals received standard rat chow only. The major circle of Willis arteries was dissected at 1 year following carotid ligation, and the proportions of animals with aneurysms were compared between groups using Fisher's exact test. Four animals given oral doxycycline and ten control animals expired before 1 year. Of the examined animals, eight saccular intracranial aneurysms were found in 8 of 45 animals which had received doxycycline (17.8%) and seven saccular intracranial aneurysms were found in 7 of 37 control animals (18.9%). There was no significant difference in aneurysm formation between the doxycycline-treated and control groups (P=0.894). Nonspecific MMP inhibition with doxycycline is not effective in preventing intracranial aneurysm formation in a rat model. (orig.)

  13. A failure of matrix metalloproteinase inhibition in the prevention of rat intracranial aneurysm formation

    International Nuclear Information System (INIS)

    We tested the hypothesis that nonspecific matrix metalloproteinase (MMP) inhibition with doxycycline would decrease the incidence of intracranial aneurysm formation in a rat aneurysm model. We performed common carotid artery ligation on 96 Long-Evans rats. A treatment group of 48 animals was chosen at random to receive oral doxycycline (3 mg/kg) in addition to standard rat chow, and the control group of 48 animals received standard rat chow only. The major circle of Willis arteries was dissected at 1 year following carotid ligation, and the proportions of animals with aneurysms were compared between groups using Fisher's exact test. Four animals given oral doxycycline and ten control animals expired before 1 year. Of the examined animals, eight saccular intracranial aneurysms were found in 8 of 45 animals which had received doxycycline (17.8%) and seven saccular intracranial aneurysms were found in 7 of 37 control animals (18.9%). There was no significant difference in aneurysm formation between the doxycycline-treated and control groups (P=0.894). Nonspecific MMP inhibition with doxycycline is not effective in preventing intracranial aneurysm formation in a rat model. (orig.)

  14. Transluminal Attenuation Gradient for Thrombotic Risk Assessment in Kawasaki Disease Patients with Coronary Artery Aneurysms

    Science.gov (United States)

    Grande Gutierrez, Noelia; Kahn, Andrew; Burns, Jane; Marsden, Alison

    2014-11-01

    Kawasaki Disease (KD) can result in coronary aneurysms in up to 25% of patients if not treated early putting patients at risk of thrombus formation, myocardial infarction and sudden death. Clinical guidelines for administering anti-coagulation therapy currently rely on anatomy alone. Previous studies including patient specific modeling and computer simulations in KD patients have suggested that hemodynamic data can predict regions susceptible to thrombus formation. In particular, high Particle Residence Time gradient (PRTg) regions have shown to correlate with regions of thrombus formation. Transluminal Attenuation Gradient (TAG) is determined from the change in radiological attenuation per vessel length. TAG has been used for characterizing coronary artery stenoses, however this approach has not yet been used in aneurysmal vessels. The aim of this study is to analyze the correlation between TAG and PRTg in KD patients with aneurysms and evaluate the use of TAG as an index to quantify thrombotic risk. Patient specific anatomic models for fluids simulations were constructed from CT angiographic image data from 3 KD aneurysm patients and one normal control. TAG values for the aneurysm patients were markedly lower than for the non-aneurysmal patient (mean -18.38 vs. -2). In addition, TAG values were compared to PRTg obtained for each patient. Thrombotic risk stratification for KD aneurysms may be improved by incorporating TAG and should be evaluated in future prospective studies.

  15. Endovascular treatment of experimentally induced aneurysms in rabbits using stents: a feasibility study

    International Nuclear Information System (INIS)

    Although Guglielmi detachable coil (GDC) systems have been generally accepted for treatment of intracranial aneurysms, primary stenting of aneurysms using porous stents or implantation of coils after stent placement remains experimental. Testing of these new methods requires an animal model which imitates human aneurysms in size, configuration and neck morphology. We assessed in detail the technical requirements of and steps for transfemoral stent treatment of experimentally induced aneurysms at the top of the brachiocephalic trunk in rabbits. We created aneurysms in ten rabbits by distal ligation and intraluminal digestion of the right common carotid artery with elastase. We treated five animals with porous stents alone, and five with stents plus coiling via the meshes of the stent, which permitted dense packing of coils. No complications related to the procedures occurred. In all animals, even in those treated solely with porous stents, total occlusion of the aneurysm was achieved. Our animal model can be suitable for testing the biocompatibility and occlusion rate of new methods and devices for the treatment of experimental aneurysms. (orig.)

  16. 基于ARCH族模型的超灵便型船运价指数研究%Supramax BSI Index Based on ARCH Family Models

    Institute of Scientific and Technical Information of China (English)

    王铖; 林国龙; 丁一

    2013-01-01

    In order to research the volatility of BSI index and grasp the trend of supramax shipping market,the supramax index return series was proved to be stationary and have higher heteroscedasticity after analyzing and testing.The GARCH (2,1) model with the student-t distribution can reflect the volatility clustering phenomenon well by analysis and comparison.And then,the reasons of some special volatility were discussed.Finally,leverage effect of BSI return series was figured out by analysis and comparison of TARCH model and EGARCH model.The conclusion of this research can provide a scientific decision-making for supramax shipping operation.%为了研究超灵便型船运价指数的波动性,把握超灵便型船运市场的走势,通过对超灵便型船收益率序列的平稳性和异方差性的分析和检验,验证了BSI日收益率序列的平稳性和高阶异方差性.通过分析比较得出基于t分布的GARCH(2,1)模型,能够更好地描述BSI日收益率序列的波动集聚效应,结合实际分析了BSI指数特殊波动的原因.最后利用TARCH模型和EGARCH模型对比分析得出BSI日收益率序列的杠杆效应.其研究成果可以为超灵便型船的航运经营提供决策支持.

  17. archAR: an archaeological augmented reality experience

    Science.gov (United States)

    Wiley, Bridgette; Schulze, Jürgen P.

    2015-03-01

    We present an application for Android phones or tablets called "archAR" that uses augmented reality as an alternative, portable way of viewing archaeological information from UCSD's Levantine Archaeology Laboratory. archAR provides a unique experience of flying through an archaeological dig site in the Levantine area and exploring the artifacts uncovered there. Using a Google Nexus tablet and Qualcomm's Vuforia API, we use an image target as a map and overlay a three-dimensional model of the dig site onto it, augmenting reality such that we are able to interact with the plotted artifacts. The user can physically move the Android device around the image target and see the dig site model from any perspective. The user can also move the device closer to the model in order to "zoom" into the view of a particular section of the model and its associated artifacts. This is especially useful, as the dig site model and the collection of artifacts are very detailed. The artifacts are plotted as points, colored by type. The user can touch the virtual points to trigger a popup information window that contains details of the artifact, such as photographs, material descriptions, and more.

  18. Research on Three-dimensional Finite Element Modeling of Human Foot and Effect of Arch Support Insert Height on Foot Comfort%足三维有限元建模及鞋垫腰窝高度对足舒适性的影响研究

    Institute of Scientific and Technical Information of China (English)

    林田; 王伟

    2015-01-01

    探讨建立足部三维有限元模型的方法,并建立一系列腰窝高度的鞋垫模型,应用模型模拟分析得出足底压力分布及骨骼受力情况,找出穿着最舒适时的腰窝高度。基于CT数据,建立包括骨骼,软骨,软组织,韧带和足底腱膜,考虑材料非线性的足部模型。截取腰窝曲面,建立5个腰窝高度的鞋垫模型。利用完整的有限元模型对行走中立期进行了静态模拟。有限元分析结果表明,满腰窝高度的鞋垫会对第二跖骨造成压迫,降低舒适感;综合舒适度函数可得出1/2-3/4腰窝高度的鞋垫具有最佳的舒适性,与实验得出的结论相同。提出从足舒适度角度设计鞋垫的腰窝高度时应综合考虑足底压力分布和跖骨应力,为设计鞋垫和研究足部各种临床状况提供了参考。%To investigate the best arch support insert height, a three-dimensional ( 3D) parametric comprehensive finite element ( FE) model of foot is established and the relationship between the plantar pressure and foot bone stress and the arch support insert is studied. Based on 3D CT scanned data of the right foot of a healthy volunteer, an accurate foot geometric model, including bones, cartilages, soft tissue, ligaments and plantar fascia, and 5 arch support inserts geometric models of different height overlald with the curved arch surface are established. The overal foot-insert FE model is established by combining the foot and arch support insert model, and the static finite element analysis of gait mid-stance phase is performed by considering the material nonlinearity. The para-metric FE analysis results show that the 2nd metatarsal is squeezed and the foot comfort is decreased with ful arch support insert, and the most favorable insert height is between 1/2-3/4 arch height from the plantar pressure effect and metatarsal stress effect, which is the same to the experimental result. Both the plantar pressure

  19. Idiopathic thoracic aortic aneurysm at pediatric age.

    Science.gov (United States)

    Marín-Manzano, E; González-de-Olano, D; Haurie-Girelli, J; Herráiz-Sarachaga, J I; Bermúdez-Cañete, R; Tamariz-Martel, A; Cuesta-Gimeno, C; Pérez-de-León, J

    2009-03-01

    A 6-year-old-boy presented with epigastric pain and vomiting over 1 year. Chest X-ray and esophagogastric transit showed a mediastinal mass. A chest computerized tomography angiogram demonstrated a descending thoracic aortic aneurysm. Analytical determinations carried out were all negative. The aneurysm was surgically repaired using a Dacron patch. The anatomopathological study described atherosclerotic lesions with calcifications, compatible with an atherosclerotic aneurysm wall. Aneurysms are uncommon in the pediatric population. Usually, no pathogenesis can be determined, and thus, such cases are grouped as idiopathic. Direct repair with or without patch is a therapeutic alternative in pediatric aneurysms and can allow the growth of the aortic circumference.

  20. Combined treatment for complex intracranial aneurysm

    Directory of Open Access Journals (Sweden)

    Chiriac A.

    2015-06-01

    Full Text Available Complex aneurysms often cannot be completely excluded by a single approaches. Today successful treatment of these lesions requires a combination between microsurgical and endovascular techniques. Planning of combined treatment require a very good understanding of aneurysm anatomy and a close collaboration between neurosurgeon and neuroendovascular interventionist. Endovascular coiling can usually be used as early treatment for a partially aneurysm occlusion including the ruptured area and followed by definitive clipping. On the other hand microsurgical clipping also can be used as first treatment for complex aneurysm neck reconstruction, allowing successful secondary placement of coils inside the remnant aneurysm sac

  1. Aneurysmal wall enhancement and perianeurysmal edema after endovascular treatment of unruptured cerebral aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Su, I. Chang [Toronto Western Hospital, Division of Neuroradiology, Department of Medical Imaging, Toronto, ON (Canada); Taipei Cathay General Hospital, Division of Neurosurgery, Department of Surgery, Taipei (China); Willinsky, Robert A.; Agid, Ronit [Toronto Western Hospital, Division of Neuroradiology, Department of Medical Imaging, Toronto, ON (Canada); Fanning, Noel F. [Cork University Hospital, Department of Interventional Neuroradiology, Cork (Ireland)

    2014-06-15

    Perianeurysmal edema and aneurysm wall enhancement are previously described phenomenon after coil embolization attributed to inflammatory reaction. We aimed to demonstrate the prevalence and natural course of these phenomena in unruptured aneurysms after endovascular treatment and to identify factors that contributed to their development. We performed a retrospective analysis of consecutively treated unruptured aneurysms between January 2000 and December 2011. The presence and evolution of wall enhancement and perianeurysmal edema on MRI after endovascular treatment were analyzed. Variable factors were compared among aneurysms with and without edema. One hundred thirty-two unruptured aneurysms in 124 patients underwent endovascular treatment. Eighty-five (64.4 %) aneurysms had wall enhancement, and 9 (6.8 %) aneurysms had perianeurysmal brain edema. Wall enhancement tends to persist for years with two patterns identified. Larger aneurysms and brain-embedded aneurysms were significantly associated with wall enhancement. In all edema cases, the aneurysms were embedded within the brain and had wall enhancement. Progressive thickening of wall enhancement was significantly associated with edema. Edema can be symptomatic when in eloquent brain and stabilizes or resolves over the years. Our study demonstrates the prevalence and some appreciation of the natural history of aneurysmal wall enhancement and perianeurysmal brain edema following endovascular treatment of unruptured aneurysms. Aneurysmal wall enhancement is a common phenomenon while perianeurysmal edema is rare. These phenomena are likely related to the presence of inflammatory reaction near the aneurysmal wall. Both phenomena are usually asymptomatic and self-limited, and prophylactic treatment is not recommended. (orig.)

  2. A Comparison Study of Stress Distribution Around Dental Implants in Three Mandibular Arch Types by Finite lement Analysis

    Directory of Open Access Journals (Sweden)

    Monzavi A

    2000-06-01

    Full Text Available The geometric shape of dental arch (square, tapering, ovoid is an important factor in stress distribution pattern around dental implant. The aim of this study was to evaluate the role of arch form and the amount of bone loss (normal, moderate, high in stress distribution around dental implant by considering different load direction. Three arch forms; square, ovoid, and tapering with three different stages of bone loss were designed. Models were divided into three-dimensional elements, which made 5500 nodes. The 143N load was applied at two angles (straight, oblique at the last fixture, 8mm, and 16 mm from the center of implant on l!ie cantilever. The Sap90 software was used for analyzing the stress distribution in this study. 54 different conditions were evaluated. Results showed that stress concentration changed from support toward fixture due to distally changing the load in the square and ovoid arch forms with normal bone. In the tapering arch with normal bone stress concentration was around the fixture. The amount of stress in normal tapering arch was more than physiologic extend, therefore, application of cantilever in tapering arches is not recommended.

  3. Earthquake safety assessment of concrete arch and gravity dams

    Institute of Scientific and Technical Information of China (English)

    Lin Gao; Hu Zhiqiang

    2005-01-01

    Based on research studies currently being carried out at Dalian University of Technology, some important aspects for the earthquake safety assessment of concrete dams are reviewed and discussed. First, the rate-dependent behavior of concrete subjected to earthquake loading is examined, emphasizing the properties of concrete under cyclic and biaxial loading conditions. Second, a modified four-parameter Hsieh-Ting-Chen viscoplastic consistency model is developed to simulate the rate-dependent behavior of concrete. The earthquake response of a 278m high arch dam is analyzed, and the results show that the strain-rate effects become noticeable in the inelastic range. Third, a more accurate non-smooth Newton algorithm for the solution of three-dimensional frictional contact problems is developed to study the joint opening effects of arch dams during strong earthquakes. Such effects on two nearly 300m high arch dams have been studied. It was found that the canyon shape has great influence on the magnitude and distribution of the joint opening along the dam axis. Fourth, the scaled boundary finite element method presented by Song and Wolf is employed to study the dam-reservoir-foundation interaction effects of concrete dams. Particular emphases were placed on the variation of foundation stiffness and the anisotropic behavior of the foundation material on the dynamic response of concrete dams. Finally, nonlinear modeling of concrete to study the damage evolution of concrete dams during strong earthquakes is discussed. An elastic-damage mechanics approach for damage prediction of concrete gravity dams is described as an example. These findings are helpful in understanding the dynamic behavior of concrete dams and promoting the improvement of seismic safety assessment methods.

  4. The origin and significance of secondary flows in the aortic arch.

    Science.gov (United States)

    Black, M M; Hose, D R; Lawford, P V

    1995-01-01

    This paper comprises a study of the secondary flow patterns that can develop in the human aortic arch. Clinical evidence of these secondary flows has been obtained by Kilner et al. using magnetic resonance velocity mapping techniques. Some of their results are presented for comparison in this paper. Four difference parametric models of the aortic arch have been analysed using computational fluid dynamic techniques. Both steady and transient flow conditions have been considered and two different commercially available software packages were used, namely FIDAP and FLOTRAN. A satisfactory comparison of the theoretical analysis with the results, both in vivo and in vitro, obtained by Kilner et al. for their out-of-plane inlet model was found. The theoretical analysis can now be extended to analyse the effect of different configurations and orientations of artificial aortic valves on the resulting aortic arch flow patterns.

  5. 磷酸化Akt和ERK在大鼠腹主动脉瘤中的表达*%Expressions of Akt and ERK Phosphorylation in Rat Model of Abdominal Aortic Aneurysm

    Institute of Scientific and Technical Information of China (English)

    郑红波; 周洪莲; 武亚丽; 周丹

    2013-01-01

      目的观察磷酸化Akt(p-Akt)和磷酸化ERK(p-ERK)在大鼠腹主动脉瘤模型中的表达情况,探讨腹主动脉瘤的发病机制。方法构建大鼠腹主动脉瘤模型并测量腹主动脉直径,计算直径扩张度;HE染色观察腹主动脉的病理改变;免疫组织化学技术和Western blot技术检测腹主动脉组织中p-Akt和p-ERK的相对表达量。结果腹主动脉瘤组主动脉扩张度(3.689±0.443)明显高于生理盐水组(1.175±0.159)和正常组(1),差异有统计学意义(P<0.05);HE染色显示,腹主动脉瘤组主动脉结构紊乱并有炎症细胞浸润;免疫组化结果和Western blot结果均显示p-Akt在腹主动脉瘤组中的表达明显高于生理盐水组和正常组(P<0.05);p-ERK表达差异不明显(P>0.05)。在腹主动脉瘤组中,p-Akt表达水平与主动脉扩张度呈正相关,p-ERK表达水平与主动脉扩张度无明显相关性。结论 PI3K/Akt信号通路可能参与腹主动脉瘤的发生与发展。%Objective To observe the expressions of Akt and ERK phosphorylation in abdominal aortic aneurysm of rat model, and explore the pathogenesis of abdominal aortic aneurysm. Methods The rat model of abdominal aortic aneu-rysm was established. The diameter of abdominal aorta was measured and the extended rate of the aorta was calculated. HE staining was used to observe the change of pathology. Immunohistochemistry and Western blot methods were used to detect the expressions of Akt and ERK phosphorylation in the level of protein. Results The dilation of aorta was significantly high-er in abdominal aortic aneurysm group than that of saline group and normal group (P0.05). Conclusion PI3K/Akt signaling pathway may be involved in the development of abdominal aortic aneurysm.

  6. The hemodynamics in intracranial aneurysm ruptured region with active contrast leakage during computed tomography angiography

    Science.gov (United States)

    Li, Ming-Lung; Wang, Yi-Chou; Liou, Tong-Miin; Lin, Chao-An

    2014-10-01

    Precise locations of rupture region under contrast agent leakage of five ruptured cerebral artery aneurysms during computed tomography angiography, which is to our knowledge for the first time, were successfully identified among 101 patients. These, together with numerical simulations based on the reconstructed aneurysmal models, were used to analyze hemodynamic parameters of aneurysms under different cardiac cyclic flow rates. For side wall type aneurysms, different inlet flow rates have mild influences on the shear stresses distributions. On the other hand, for branch type aneurysms, the predicted wall shear stress (WSS) correlates strongly with the increase of inlet vessel velocity. The mean and time averaged WSSes at rupture regions are found to be lower than those over the surface of the aneurysms. Also, the levels of the oscillatory shear index (OSI) are higher than the reported threshold value, supporting the assertion that high OSI correlates with rupture of the aneurysm. However, the present results also indicate that OSI level at the rupture region is relatively lower.

  7. NUMERICAL SIMULATION AND ANALYSIS ON THE HEMODYNAMICS OF AN ELASTIC ANEURYSM

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun-wei; YIN Wen-yi; DING Guang-hong; YANG Xin-jian; SHI Wan-chao; ZHANG Xiao-long

    2008-01-01

    Intracranial aneurysms are pathological dilatations which endanger people's health. Hemodynamics is thought to be an important factor in the pathogenesis and treatment of aneurysms. To date, the bulk of investigations into hemodynamics have been conducted by making use of mathematically idealized models for rigid aneurysms and associated arteries. However the walls of aneurysms and associated arteries are elastic in vivo. This study shows the differences of the simulation between elastic and rigid wall models. The numerical simulation of elastic aneurysm model is made from a representative Digital Subtraction Angiography (DSA) image and calculated with CFD software to get the wall deformation and the velocity field. Then the results are analyzed. By comparing the simulation results of the two models from their velocity vectors and shear stress distribution, many differences can be noted. The main difference exists in the distribution of velocity magnitude at some sections, with one outlet having obviously off-center distribution for the elastic wall model. The currents of the distribution of wall shear stress along the wall of aneurysm simulated in rigid and elastic wall models were similar. But there were apparent differences between the two models on the values of wall shear stress especially at the neck of aneurysm. The off-center distribution of velocity magnitude affects the distribution of wall shear stress and the exchange of substance through the wall. The analysis demonstrated clearly that the results of 2-D elastic numerical simulation were in good agreement with the clinical and pathological practice. The results of this study play an important role in the formation, growth, rupture and prognosis of an aneurysm on clinic application.

  8. In-plane elastic stability of fixed parabolic shallow arches

    Institute of Scientific and Technical Information of China (English)

    CAI JianGuo; FENG Jian; CHEN Yao; HUANG LiFeng

    2009-01-01

    The nonlinear behavior of fixed parabolic shallow arches subjected to a vertical uniform load is inves-tigated to evaluate the in-plane buckling load. The virtual work principle method is used to establish the non-linear equilibrium and buckling equations. Analytical solutions for the non-linear in-plane sym-metric snap-through and antisymmetric bifurcation buckling loads are obtained. Based on the least square method, an approximation for the symmetric buckling load of fixed parabolic arch is proposedto simplify the solution process. And the relation between modified slenderness and buckling modes are discussed. Comparisons with the results of finite element analysis demonstrate that the solutions are accurate. A cable-arch structure is presented to improve the in-plane stability of parabolic arches. The comparison of buckling loads between cable-arch systems and arches only show that the effect of cables becomes more evident with the increase of arch's modified slenderness.

  9. Effect of dental arch convexity and type of archwire on frictional forces

    NARCIS (Netherlands)

    Fourie, Zacharias; Ozcan, Mutlu; Sandham, John

    2009-01-01

    Introduction: Friction measurements in orthodontics are often derived from models by using brackets placed on flat models with various straight wires. Dental arches are convex in some areas. The objectives of this study were to compare the frictional forces generated in conventional flat and convex

  10. Septal aneurysm with associated anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Krcilkova, M.; Rubin, A.; Bret, J.; Michaljanic, A.; Hradec, J.; Jezek, M.; Jezkova, L.; Hamanova, H.; Stranakova, J.

    1985-09-01

    A 15-year-old boy had a history of a functional systolic murmur with systolic and diastolic murmurs and radiological evidence of left ventricular hypertrophy. The angiocardiogram demonstrated an aneurysm of the membranous septum, bicuspid aortic valve, dilatation of the left subclavian artery and left common carotid artery. Echocardiography showed a holosystolic prolapse of the mitral valve with mitral insufficiency and a bicuspid aortic valve with insignificant incompetence of the aortic valve. Classical TM mode echocardiography did not show an aneurysm of the membranous septum.

  11. Septal aneurysm with associated anomalies

    International Nuclear Information System (INIS)

    A 15-year-old boy had a history of a functional systolic murmur with systolic and diastolic murmurs and radiological evidence of left ventricular hypertrophy. The angiorcardiogram demonstrated an aneurysm of the membranous septum, bicuspid aortic valve, dilatation of the left subclavian artery and left common carotid artery. Echocardiography showed a holosystolic prolapse of the mitral valve with mitral insufficiency and a bicuspid aortic valve with insignificant incompetence of the aortic valve. Classical TM mode echocardiography did not show an aneurysm of the membranous septum. (orig.)

  12. Vortex Dynamics in Cerebral Aneurysms

    CERN Document Server

    Byrne, Greg

    2013-01-01

    We use an autonomous three-dimensional dynamical system to study embedded vortex structures that are observed to form in computational fluid dynamic simulations of patient-specific cerebral aneurysm geometries. These structures, described by a vortex which is enclosed within a larger vortex flowing in the opposite direction, are created and destroyed in phase space as fixed points undergo saddle-node bifurcations along vortex core lines. We illustrate how saddle-node bifurcations along vortex core lines also govern the formation and evolution of embedded vortices in cerebral aneurysms under variable inflow rates during the cardiac cycle.

  13. Behaviour of Steel Arch Stabilized by a Textile Membrane

    Science.gov (United States)

    Svoboda, O.; Machacek, J.

    2015-11-01

    Behaviour of the slender steel arch supporting textile membranes in a membrane structure with respect to in-plane and out-of plane stability is investigated in the paper. In the last decades the textile membranes have been widely used to cover both common and exclusive structures due to progress in new membrane materials with eminent properties. Nevertheless, complex analysis of such membranes in interaction with steel structure (carbon/stainless steel perimeter or supporting elements) is rather demanding, even with specialized software. Laboratory model of a large membrane structure simulating a shelter roof of a concert stage was tested and the resulting stress/deflection values are presented. The model of a reasonable size was provided with prestressed membrane of PVC coated polyester fabric Ferrari® Précontraint 702S and tested under various loadings. The supporting steel structure consisted of two steel arch tubes from S355 grade steel and perimeter prestressed cables. The stability behaviour of the inner tube was the primary interest of the investigation. The SOFiSTiK software was used to analyse the structural behaviour in 3D. Numerical non-linear analysis of deflections and internal forces of the structure under symmetrical and asymmetrical loadings covers various membrane prestressing and specific boundary conditions. The numerical results are validated using test results. Finally, the preliminary recommendations for appropriate numerical modelling and stability design of the supporting structure are presented.

  14. Patient specific stress and rupture analysis of ascending thoracic aneurysms.

    Science.gov (United States)

    Trabelsi, Olfa; Davis, Frances M; Rodriguez-Matas, Jose F; Duprey, Ambroise; Avril, Stéphane

    2015-07-16

    An ascending thoracic aortic aneurysm (ATAA) is a serious medical condition which, more often than not, requires surgery. Aneurysm diameter is the primary clinical criterion for determining when surgical intervention is necessary but, biomechanical studies have suggested that the diameter criterion is insufficient. This manuscript presents a method for obtaining the patient specific wall stress distribution of the ATAA and the retrospective rupture risk for each patient. Five human ATAAs and the preoperative dynamic CT scans were obtained during elective surgeries to replace each patient's aneurysm with a synthetic graft. The material properties and rupture stress for each tissue sample were identified using bulge inflation tests. The dynamic CT scans were used to generate patient specific geometries for a finite element (FE) model of each patient's aneurysm. The material properties from the bulge inflation tests were implemented in the FE model and the wall stress distribution at four different pressures was estimated. Three different rupture risk assessments were compared: the maximum diameter, the rupture risk index, and the overpressure index. The peak wall stress values for the patients ranged from 28% to 94% of the ATAA's failure stress. The rupture risk and overpressure indices were both only weakly correlated with diameter (ρ=-0.29, both cases). In the future, we plan to conduct a large experimental and computational study that includes asymptomatic patients under surveillance, patients undergoing elective surgery, and patients who have experienced rupture or dissection to determine if the rupture risk index or maximum diameter can meaningfully differentiate between the groups. PMID:25979384

  15. Comparison of two stents in modifying cerebral aneurysm hemodynamics.

    Science.gov (United States)

    Kim, Minsuok; Taulbee, Dale B; Tremmel, Markus; Meng, Hui

    2008-05-01

    There is a general lack of quantitative understanding about how specific design features of endovascular stents (struts and mesh design, porosity) affect the hemodynamics in intracranial aneurysms. To shed light on this issue, we studied two commercial high-porosity stents (Tristar stent and Wallstent) in aneurysm models of varying vessel curvature as well as in a patient-specific model using Computational Fluid Dynamics. We investigated how these stents modify hemodynamic parameters such as aneurysmal inflow rate, stasis, and wall shear stress, and how such changes are related to the specific designs. We found that the flow damping effect of stents and resulting aneurysmal stasis and wall shear stress are strongly influenced by stent porosity, strut design, and mesh hole shape. We also confirmed that the damping effect is significantly reduced at higher vessel curvatures, which indicates limited usefulness of high-porosity stents as a stand-alone treatment. Finally, we showed that the stasis-inducing performance of stents in 3D geometries can be predicted from the hydraulic resistance of their flat mesh screens. From this, we propose a methodology to cost-effectively compare different stent designs before running a full 3D simulation. PMID:18264766

  16. Development of Image Segmentation Methods for Intracranial Aneurysms

    Directory of Open Access Journals (Sweden)

    Yuka Sen

    2013-01-01

    Full Text Available Though providing vital means for the visualization, diagnosis, and quantification of decision-making processes for the treatment of vascular pathologies, vascular segmentation remains a process that continues to be marred by numerous challenges. In this study, we validate eight aneurysms via the use of two existing segmentation methods; the Region Growing Threshold and Chan-Vese model. These methods were evaluated by comparison of the results obtained with a manual segmentation performed. Based upon this validation study, we propose a new Threshold-Based Level Set (TLS method in order to overcome the existing problems. With divergent methods of segmentation, we discovered that the volumes of the aneurysm models reached a maximum difference of 24%. The local artery anatomical shapes of the aneurysms were likewise found to significantly influence the results of these simulations. In contrast, however, the volume differences calculated via use of the TLS method remained at a relatively low figure, at only around 5%, thereby revealing the existence of inherent limitations in the application of cerebrovascular segmentation. The proposed TLS method holds the potential for utilisation in automatic aneurysm segmentation without the setting of a seed point or intensity threshold. This technique will further enable the segmentation of anatomically complex cerebrovascular shapes, thereby allowing for more accurate and efficient simulations of medical imagery.

  17. Approach for analyzing the ultimate strength of concrete filled steel tubular arch bridges with stiffening girder

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-cheng; XIE Xu; ZHANG He; CHEN Heng-zhi

    2007-01-01

    A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders isinvestigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.

  18. FLOOD DISCHARGE AND ENERGY DISSIPATION BY JETS FROM OUTLETS IN HIGH ARCH DAM

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this thesis, the downstream local rock-bed scour by multiple layered jets and by the collision of water jets in vertical and transverse directions were studied and the stability of the inverted arch cushion pool were analyzed. The velocity distribution of an aerated jet running dwon in the pool is obtained, a new method to calculate the scour depth by multiple layered jets and by the collision of water jets was proposed, and a muthematical model to forecast the critical downstream depth as a slab with various specific gravity destructions was established. The results were verified by experimental research on the hydrodynamic pressure produced at gaps of the inverted arch type of wate cushion pool and by using an advanced measurement and the imitation method experiments on forces at both arch spandrels were carried out to find their characteristics.

  19. Building problem solving environments with the arches framework

    Energy Technology Data Exchange (ETDEWEB)

    Debardeleben, Nathan [Los Alamos National Laboratory; Sass, Ron [U NORTH CAROLINA; Stanzione, Jr., Daniel [ASU; Ligon, Ill, Walter [CLEMSON UNIV

    2009-01-01

    The computational problems that scientists face are rapidly escalating in size and scope. Moreover, the computer systems used to solve these problems are becoming significantly more complex than the familiar, well-understood sequential model on their desktops. While it is possible to re-train scientists to use emerging high-performance computing (HPC) models, it is much more effective to provide them with a higher-level programming environment that has been specialized to their particular domain. By fostering interaction between HPC specialists and the domain scientists, problem-solving environments (PSEs) provide a collaborative environment. A PSE environment allows scientists to focus on expressing their computational problem while the PSE and associated tools support mapping that domain-specific problem to a high-performance computing system. This article describes Arches, an object-oriented framework for building domain-specific PSEs. The framework was designed to support a wide range of problem domains and to be extensible to support very different high-performance computing targets. To demonstrate this flexibility, two PSEs have been developed from the Arches framework to solve problem in two different domains and target very different computing platforms. The Coven PSE supports parallel applications that require large-scale parallelism found in cost-effective Beowulf clusters. In contrast, RCADE targets FPGA-based reconfigurable computing and was originally designed to aid NASA Earth scientists studying satellite instrument data.

  20. Designing light responsive bistable arches for rapid, remotely triggered actuation

    Science.gov (United States)

    Smith, Matthew L.; Shankar, M. Ravi; Backman, Ryan; Tondiglia, Vincent P.; Lee, Kyung Min; McConney, Michael E.; Wang, David H.; Tan, Loon-Seng; White, Timothy J.

    2014-03-01

    Light responsive azobenzene functionalized polymer networks enjoy several advantages as actuator candidates including the ability to be remotely triggered and the capacity for highly tunable control via light intensity, polarization, wavelength and material alignments. One signi cant challenge hindering these materials from being employed in applications is their often relatively slow actuation rates and low power densities, especially in the absence of photo-thermal e ects. One well known strategy employed in nature for increasing actuation rate and power output is the storage and quick release of elastic energy (e.g., the Venus ytrap). Using nature as inspiration we have conducted a series of experiments and developed an equilibrium mechanics model for investigating remotely triggered snap-through of bistable light responsive arches made from glassy azobenzene functionalized polymers. After brie y discussing experimental observations we consider in detail a geometrically exact, planar rod model of photomechanical snap-through. Theoretical energy release characteristics and unique strain eld pro les provide insight toward design strategies for improved actuator performance. The bistable light responsive arches presented here are potentially a powerful option for remotely triggered, rapid motion from apparently passive structures in applications such as binary optical switches and positioners, surfaces with morphing topologies, and impulse locomotion in micro or millimeter scale robotics.

  1. Biotechnologie des archées

    OpenAIRE

    Querellou, Joel

    2010-01-01

    La majorité des enzymes utilisées dans l’industrie provient des bactéries et des levures. Mais les conditions extrêmes dans lesquelles se développent de nombreuses espèces d’archées font que leurs constituants cellulaires possèdent des propriétés et une stabilité propices à leur utilisation en biotechnologie.

  2. Recurrent Pneumonia due to Double Aortic Arch

    Directory of Open Access Journals (Sweden)

    I. Sedighi

    2012-04-01

    Full Text Available Introduction: Pneumonia is one of the most common infections during childhood. In children with recurrent bacterial pneumonia complete evaluation for underlying factors is necessary. The most common underlying diseases include: antibody deficiencies , cystic fibrosis , tracheoesophageal fistula and increased pulmonary blood flow. Vascular ring and its pressure effect is a less common cause of stridor and recurrent pneumonia. Congenital abnormalities in aortic arch and main branches which form vascular ring around esophagus and trachea with variable pressure effect cause respiratory symptoms such as stridor , wheezing and recurrent pneumoniaCase Report: A 2 year old boy was admitted in our hospital with respiratory distress and cough . Chest x-Ray demonstrated right lobar pneumonia. He had history of stridor and wheezing from neonatal period and hospitalization due to pneumonia for four times. The patient received appropriate antibiotics. Despite fever and respiratory distress improvement, wheezing continued. Review of his medical documents showed fixed pressure effect on posterior aspect of esophagus in barium swallow. In CT angiography we confirmed double aortic arch.Conclusion: Double aortic arch is one of the causes of persistant respiratory symptom and recurrent pneumonia in children for which fluoroscopic barium swallow is the first non-invasive diagnostic method.(Sci J Hamadan Univ Med Sci 2012;19(1:70-74

  3. The Numerical Study of the Hemodynamic Characteristics in the Patient-Specific Intracranial Aneurysms before and after Surgery

    Science.gov (United States)

    Byun, Jun Soo; Choi, Sun-Young

    2016-01-01

    The patient-specific pre- and postsurgery cerebral arterial geometries in the study were reconstructed from computed tomography angiography (CTA). Three-dimensional computational fluid dynamics models were used to investigate the hemodynamic phenomena in the cerebral arteries before and after surgery of the aneurysm under realistic conditions. CFD simulations for laminar flow of incompressible Newtonian fluid were conducted by using commercial software, ANSYS v15, with the rigid vascular wall assumption. The study found that the flow patterns with the complex vortical structures inside the aneurysm were similar. We also found that the inflow jet streams were coming strongly in aneurysm sac in the presurgery models, while the flow patterns in postsurgery models were quite different from those in presurgery models. The average wall shear stress after surgery for model 1 was approximately three times greater than that before surgery, while it was about twenty times greater for model 2. The area of low WSS in the daughter saccular aneurysm region in model 2 is associated with aneurysm rupture. Thus the distribution of WSS in aneurysm region provides useful prediction for the risk of aneurysm rupture. PMID:27274764

  4. Validation of CFD Simulations of Cerebral Aneurysms With Implication of Geometric Variations

    OpenAIRE

    Hoi, Yiemeng; Woodward, Scott H.; Kim, Minsuok; Taulbee, Dale B.; Meng, Hui

    2006-01-01

    Computational fluid dynamics (CFD) simulations using medical-image-based anatomical vascular geometry are now gaining clinical relevance. This study aimed at validating the CFD methodology for studying cerebral aneurysms by using particle image velocimetry (PIV) measurements, with a focus on the effects of small geometric variations in aneurysm models on the flow dynamics obtained with CFD. Method of Approach. An experimental phantom was fabricated out of silicone elastomer to best mimic a sp...

  5. Oculomotor Paresis and Basilar Aneurysm

    OpenAIRE

    J Gordon Millichap

    1992-01-01

    The clinical and pathologic findings in a 10 month old girl with congenital heart diseasewho died after rupture of a congenital distal basilar artery aneurysm are reported from the University of Connecticut Health Center, Farmington, CT and the Children’s Hospital of Philadelphia, PA.

  6. Neural Network in Developing Software for Indentifying Arch Form

    Directory of Open Access Journals (Sweden)

    Johan Arief Budiman

    2013-06-01

    Full Text Available The treatment of Class I malocclusion treatment is to arrange the teeth position in a good arch form. Archform consists of tooth size and arch dimension (intercanine width, canine depth, intermolar width, molardepth. Several ways are developed to describe arch form. A lot of methods usedto describe arch formqualitatively.The objectiveofthis studyistodevelop qualitative arch form diagnostic references usingartificial neural network from pre-post treatment dental cast scanning result. Pre-post orthodontictreatment dental casts (1990-2006 from Post Graduate Clinic Faculty of Dentistry University of Indonesiaand 3 other orthodontistswere gathered andscanned.Dataweremeasured usingImage Toolandanalyzedusing Stata 9.ANOVA was used to compare arch forms (square, oval, tapered and gender (male andfemale, with each component of arch dimension upper and lowerjaw, before and after treatment; and alsoarch perimeter to kinds of treatmentThe results were compiled todeterminevariables inbuildingthesoftware for analyzing arch form qualitatively.The data from190 pre-post orthodontic treatment dentalcasts consisted of42 male (22.1% and 148 female (77.9% treated without extraction (32.63%,4Premolars extraction (48.42%, Upper Premolars extraction (11.05%, atypical extraction (7.90%.Gender and allvariables from pre treatment did not influence arch form, except kinds of treatment.Therefore, only post treatment data are included for arch form analysis. The shape of arch form (square,oval and tapered can be described qualitatively by software using artificial neural network.This softwarecoulddescribe arch form with the accuracy of 76.3158%.This studyconcludedthatIntercanine width,Canine depth, Intermolar width, and molar depth were variables that influencedarch form. A softwareusing artificial neural network to describe arch formqualitatively couldbe used for diagnostic reference toClass I malocclusion orthodontic post treatment.

  7. Angiographic analysis for phantom simulations of endovascular aneurysm treatments with a new fully retrievable asymmetric flow diverter

    Science.gov (United States)

    Yoganand, Aradhana; Wood, Rachel P.; Jimenez, Carlos; Siddiqui, Adnan; Snyder, Kenneth; Setlur Nagesh, S. V.; Bednarek, D. R.; Rudin, S.; Baier, Robert; Ionita, Ciprian N.

    2015-03-01

    Digital Subtraction Angiography (DSA) is the main diagnostic tool for intracranial aneurysms (IA) flow-diverter (FD) assisted treatment. Based on qualitative contrast flow evaluation, interventionists decide on subsequent steps. We developed a novel fully Retrievable Asymmetric Flow-Diverter (RAFD) which allows controlled deployment, repositioning and detachment achieve optimal flow diversion. The device has a small low porosity or solid region which is placed such that it would achieve maximum aneurysmal in-jet flow deflection with minimum impairment to adjacent vessels. We tested the new RAFD using a flow-loop with an idealized and a patient specific IA phantom in carotid-relevant physiological conditions. We positioned the deflection region at three locations: distally, center and proximally to the aneurysm orifice and analyzed aneurysm dome flow using DSA derived maps for mean transit time (MTT) and bolus arrival times (BAT). Comparison between treated and untreated (control) maps quantified the RAFD positioning effect. Average MTT, related to contrast presence in the aneurysm dome increased, indicating flow decoupling between the aneurysm and parent artery. Maximum effect was observed in the center and proximal position (~75%) of aneurysm models depending on their geometry. BAT maps, correlated well with inflow jet direction and magnitude. Reduction and jet dispersion as high as about 50% was observed for various treatments. We demonstrated the use of DSA data to guide the placement of the RAFD and showed that optimum flow diversion within the aneurysm dome is feasible. This could lead to more effective and a safer IA treatment using FDs.

  8. Numerical simulations of post-surgical flow and thrombosis in basilar artery aneurysms

    Science.gov (United States)

    Seshadhri, Santhosh; Lawton, Michael; Boussel, Loic; Saloner, David; Rayz, Vitaliy

    2015-11-01

    Surgical treatment of basilar artery aneurysms presents a major challenge since it is crucial to preserve the flow to the vital brainstem perforators branching of the basilar artery. In some cases, basilar aneurysms can be treated by clipping vessels in order to induce flow reduction and aneurysm thrombosis. Patient-specific CFD models can provide guidance to clinicians by simulating postoperative flows resulting from alternative surgeries. Several surgical options were evaluated for four basilar aneurysm patients. Patient-specific models were generated from preoperative MR angiography and MR velocimetry data and modified to simulate different procedures. The Navier-Stokes equations were solved with a finite-volume solver Fluent. Virtual contrast injections were simulated by solving the advection-diffusion equation in order to estimate the flow residence time and determine thrombus-prone regions. The results indicated on procedures that reduce intra-aneurysmal velocities and flow regions which are likely to become thrombosed. Thus CFD modeling can help improve the outcome of surgeries altering the flow in basilar aneurysms.

  9. Elastic energy within the human plantar aponeurosis contributes to arch shortening during the push-off phase of running.

    Science.gov (United States)

    Wager, Justin C; Challis, John H

    2016-03-21

    During locomotion, the lower limb tendons undergo stretch and recoil, functioning like springs that recycle energy with each step. Cadaveric testing has demonstrated that the arch of the foot operates in this capacity during simple loading, yet it remains unclear whether this function exists during locomotion. In this study, one of the arch׳s passive elastic tissues (the plantar aponeurosis; PA) was investigated to glean insights about it and the entire arch of the foot during running. Subject specific computer models of the foot were driven using the kinematics of eight subjects running at 3.1m/s using two initial contact patterns (rearfoot and non-rearfoot). These models were used to estimate PA strain, force, and elastic energy storage during the stance phase. To examine the release of stored energy, the foot joint moments, powers, and work created by the PA were computed. Mean elastic energy stored in the PA was 3.1±1.6J, which was comparable to in situ testing values. Changes to the initial contact pattern did not change elastic energy storage or late stance PA function, but did alter PA pre-tensioning and function during early stance. In both initial contact patterns conditions, the PA power was positive during late stance, which reveals that the release of the stored elastic energy assists with shortening of the arch during push-off. As the PA is just one of the arch׳s passive elastic tissues, the entire arch may store additional energy and impact the metabolic cost of running.

  10. THE EVOLUTION OF PROTOPLANETARY DISKS IN THE ARCHES CLUSTER

    International Nuclear Information System (INIS)

    Most stars form in a cluster environment. These stars are initially surrounded by disks from which potentially planetary systems form. Of all cluster environments, starburst clusters are probably the most hostile for planetary systems in our Galaxy. The intense stellar radiation and extreme density favor rapid destruction of circumstellar disks via photoevaporation and stellar encounters. Evolving a virialized model of the Arches cluster in the Galactic tidal field, we investigate the effect of stellar encounters on circumstellar disks in a prototypical starburst cluster. Despite its proximity to the deep gravitational potential of the Galactic center, only a moderate fraction of members escapes to form an extended pair of tidal tails. Our simulations show that encounters destroy one-third of the circumstellar disks in the cluster core within the first 2.5 Myr of evolution, preferentially affecting the least and most massive stars. A small fraction of these events causes rapid ejection and the formation of a weaker second pair of tidal tails that is overpopulated by disk-poor stars. Two predictions arise from our study. (1) If not destroyed by photoevaporation protoplanetary disks of massive late B- and early O-type stars represent the most likely hosts of planet formation in starburst clusters. (2) Multi-epoch K- and L-band photometry of the Arches cluster would provide the kinematically selected membership sample required to detect the additional pair of disk-poor tidal tails.

  11. Isolated iliac artery aneurysms with associated hydronephrosis.

    LENUS (Irish Health Repository)

    O'Driscoll, D

    2012-02-03

    An isolated iliac artery aneurysm is where there is aneurysmal dilatation of one or more branches of the iliac system, with no associated dilatation of the aorta. Such aneurysms are rare and comprise 1% of all intra-abdominal aneurysms. The signs and symptoms of such an aneurysm are influenced by its concealed location within the bony pelvis. Awareness of these special characteristics improves the chances of early diagnosis and proper treatment before possible rupture. We present the clinical and radiological features of three such aneurysms. Ultrasound was the first imaging modality to be performed. Ipsilateral hydronephrosis was demonstrated in each case, this lead to imaging the pelvis and the correct diagnosis. We review the clinical and radiological literature and conclude that the pelvis should be imaged in all cases of unexplained hydronephrosis.

  12. 特克斯河山口引水枢纽的 引水防沙设计及试验研究%Dynamic test and study on the integral body and model with transverse joint of Xiaowan High Arch Dam

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    通过特克斯河山口引水枢纽的试验研究,解决了常遇洪水低水位运行时河流两岸的引水问题,优化了水平悬板等结构形式,收到了较好的引水防沙效果,为悬板分层式引水枢纽工程设计提供了新经验%The dynamic test on the earthquake response of the integral dam body and model with transverse joint for Xiaowan High Arch Dam was made. In consideration that the dynamic test on the model with transverse joint falls into non-linear category, it is more sensitive to the initial condition of static action so that the test includes reservoir with a length of three times dam height. The test on expansion transverse joint was made in two working conditions. Firstly three expansion transverse joints were set up in the arch-crown beam and top arch, about 1/4 arc length of right and left banks. Then five transverse joints were increased to make dynamic test. The test showed that under the working condition of normal high water level, the transverse joint of dam body under the action of earthquake opens indistinctly. But under the low water level, the transverse joint clearly opens because of the reduction of static pressure. The dynamic tensile stress of dam body obviously reduces and the dynamic beam stress increases obviously. The initial condition of the transverse joints of dam body will bring big impact on the opening of transverse joint. On the basis of the designed reinforcement, the test showed that the opening of transverse joint reduced about 20%.

  13. Modelo experimental estável de aneurisma sacular em artéria carótida de suínos utilizando veia jugular interna Stable experimental model of carotid artery saccular aneurysm in swine using the internal jugular vein

    Directory of Open Access Journals (Sweden)

    Severino Lourenço da Silva Júnior

    2013-04-01

    Full Text Available OBJETIVO: Desenvolver um modelo experimental estável de aneurisma sacular em carótida de suínos utilizando veia jugular interna. MÉTODOS: Em 12 suínos sadios, com peso variando entre 25 e 50kg, cinco machos e sete fêmeas, foi confeccionado aneurisma na artéria carótida comum direita. Após arteriotomia elíptica, foi realizada anastomose terminolateral com coto distal de veia jugular interna. O volume do aneurisma era calculado de maneira que o valor não excedesse em 27 vezes o valor da área da arteriotomia. Após seis dias, era realizada angiografia e análise microscópica do aneurisma para avaliar perviedade e trombose parcial ou total. RESULTADOS: Houve ganho de peso significante dos suínos no intervalo de tempo entre a confecção do aneurisma e a angiografia (p = 0,04. Foi observada perviedade aneurismática em dez suínos (83%. Ocorreram infecções de feridas operatórias em dois animais (16,6%, ambas com início de aparecimento em três dias após a confecção do aneurisma. Análise histológica dos aneurismas mostrou trombos ocluindo parcialmente a luz em nove suínos (75%. Nesses animais, observou-se que, em média, 9% da luz aneurismática estava preenchida por trombos. CONCLUSÃO: Pôde ser desenvolvido um modelo experimental estável de aneurisma sacular em carótida de suínos utilizando veia jugular interna.OBJECTIVE: To develop an experimental model of stable saccular aneurysm in carotid of pigs using the internal jugular vein. METHODS: In 12 healthy pigs, weighing between 25 and 50kg, five males and seven females, we made a right common carotid artery aneurysm. After elliptical arteriotomy, we carried out a terminolateral anastomosis with the distal stump of the internal jugular vein. Aneurysm volume was calculated so that the value did not exceed 27 times the area of the arteriotomy. After six days angiography and microscopic examination were performed to assess patency of the aneurysm and the presence of total or

  14. In-plane elastic stability of fixed parabolic shallow arches

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The nonlinear behavior of fixed parabolic shallow arches subjected to a vertical uniform load is inves- tigated to evaluate the in-plane buckling load. The virtual work principle method is used to establish the non-linear equilibrium and buckling equations. Analytical solutions for the non-linear in-plane sym- metric snap-through and antisymmetric bifurcation buckling loads are obtained. Based on the least square method, an approximation for the symmetric buckling load of fixed parabolic arch is proposed to simplify the solution process. And the relation between modified slenderness and buckling modes are discussed. Comparisons with the results of finite element analysis demonstrate that the solutions are accurate. A cable-arch structure is presented to improve the in-plane stability of parabolic arches. The comparison of buckling loads between cable-arch systems and arches only show that the effect of cables becomes more evident with the increase of arch’s modified slenderness.

  15. Gender differences in cerebral aneurysm location

    OpenAIRE

    Ali Jourabchi Ghods; Demetrius eLopes; Michael eChen

    2012-01-01

    Background and Purpose: A limited number of studies consisting predominantly of ruptured aneurysms have looked at differences in anatomical distribution of aneurysms between male and females. Unlike all other causes of stroke, subarachnoid-hemorrhages (SAH) occur more often in women and are thought to be a result of both hormonal influences and variation in wall shear stress (WSS). This paper retrospectively looks at a cohort of largely unruptured intracranial aneurysms to determine if there ...

  16. MR angiography after coiling of intracranial aneurysms

    OpenAIRE

    Schaafsma, J.D.

    2012-01-01

    Introduction Endovascular occlusion with detachable coils has become an alternative treatment to neurosurgical clipping of intracranial aneurysms over the last two decades. Its minimal invasiveness is the most important advantage of this treatment compared to clipping. The disadvantage of occlusion with coils is an approximately 20% risk of reopening of the aneurysm as a result of coil impaction, dissolution of thrombus, or growth of the aneurysm and 10% of coiled patients need additional tre...

  17. Portal Vein Aneurysm Presenting with Obstructive Jaundice

    OpenAIRE

    Chandana Lall; Sadhna Verma; Rajesh Gulati; Puneet Bhargava

    2012-01-01

    To the best of our knowledge, a portal vein aneurysm presenting with obstructive jaundice has not been reported in the literature. The preferred treatment for these aneurysms is surgical and a shunting procedure should be considered in cases with portal hypertension to preserve portal vein flow when portal hypertension is present or is secondary to the aneurysm itself. In our case, due to patient′s advanced age and co-morbidities, an endoscopic biliary stent was placed which led to successful...

  18. Management of splenic artery aneurysm associatedwithextrahepaticportal veinobstruction

    Institute of Scientific and Technical Information of China (English)

    Pramod Kumar Mishra; Sundeep Singh Saluja; Ashok K Sharma; Premanand Pattnaik

    2012-01-01

    BACKGROUND: Splenic artery aneurysms although rare are clinically signiifcant in view of their propensity for spontaneous rupture and life-threatening bleeding. While portal hypertension is an important etiological factor, the majority of reported cases are secondary to cirrhosis of the liver. We report three cases of splenic artery aneurysms associated with extrahepatic portal vein obstruction and discuss their management. METHODS: The records of three patients of splenic artery aneurysm associated with extrahepatic portal vein obstruction managed from 2003 to 2010 were reviewed retrospectively. The clinical presentation, surgical treatment and outcome were analyzed. RESULTS:  The aneurysm was >3 cm in all patients. The clinical symptoms were secondary to extrahepatic portal vein obstruction (hematemesis in two, portal biliopathy in two) while the aneurysm was asymptomatic. Doppler ultrasound demonstrated aneurysms in all patients. A proximal splenorenal shunt was performed in two patients with excision of the aneurysm in one patient and ligation of the aneurysm in another one. The third patient had the splenic vein replaced by collaterals and hence underwent splenectomy with aneurysmectomy. All patients had an uneventful post-operative course. CONCLUSIONS: Splenic artery aneurysms are associated with extrahepatic portal vein obstruction. Surgery is the mainstay of treatment. Although technically dififcult, it can be safely performed in an experienced center with minimal morbidity and good outcome.

  19. Endovascular treatment for pediatric intracranial aneurysms

    International Nuclear Information System (INIS)

    The purpose of this study is to report the characteristics and outcomes of pediatric patients with intracranial aneurysms. From 1998 to 2005, 25 pediatric patients (aged ≤17 years) with intracranial aneurysm were treated at our institute. Eleven of 25 patients had subarachnoid hemorrhage. In ten patients, the aneurysm was an incidental finding. One patient presented with cranial nerves dysfunction and three with neurological deficits. The locations of the aneurysms were as follows: vertebral artery (VA; n = 9), middle cerebral artery (MCA; n = 5), posterior cerebral artery (PCA; n = 4), basilar artery (BA; n = 2), anterior communicating artery (n = 2), anterior cerebral artery (n = 2), and internal carotid artery (n = 1). Five patients were treated with selective embolization with coils. Sixteen patients were treated with parent vessel occlusion (PVO). Eight PVOs were performed with balloons and eight were performed with coils. One patient with a VA aneurysm was spontaneously thrombosed 4 days after the initial diagnostic angiogram. In three patients treated with stent alone or stent-assisted coiling, one with BA trunk aneurysm died. One aneurismal recurrence occurred and was retreated. At a mean follow-up duration of 23.5 months, 96% of patients had a Glasgow Outcome Scale score of 4 or 5. Pediatric intracranial aneurysms occur more commonly in male patients and have a predilection for the VA, PCA, and MCA. PVO is an effective and safe treatment for fusiform aneurysms. Basilar trunk fusiform aneurysms were difficult to treat and were associated with a high mortality rate. (orig.)

  20. Pathomechanisms and treatment of pediatric aneurysms.

    Science.gov (United States)

    Krings, Timo; Geibprasert, Sasikhan; terBrugge, Karel G

    2010-10-01

    Pediatric aneurysms are rare diseases distinct from classical adult aneurysms and therefore require different treatment strategies. Apart from saccular aneurysms that are more commonly found in older children, three major pathomechanisms may be encountered: trauma, infection, and dissection. The posterior circulation and more distal locations are more commonly encountered in children compared to adults, and there is an overall male predominance. Clinical findings are not only confined to subarachnoid hemorrhage but may also comprise mass effects, headaches or neurological deficits. In traumatic aneurysms, the skull base and distal anterior communicating artery are commonly affected, and the hemorrhage occurs often delayed (2-4 weeks following the initial trauma). Infectious aneurysms are mostly bacterial in origin, and hemorrhage occurs early after a septic embolic shower. Dissecting aneurysms are the most often encountered aneurysm type in children and can lead to mass effect, hemorrhage, or ischemia depending on the fate of the intramural hematoma. Treatment strategies in pediatric aneurysms include endosaccular coil treatment only for the "classical berry-type" aneurysms; in the other instances, parent vessel occlusion, flow reversal, surgical options, or a combined treatment with bypass and parent vessel occlusion have to be contemplated.

  1. Angiographic Findings In Patients With Cerebral Aneurysm

    Directory of Open Access Journals (Sweden)

    Miri S M

    2004-09-01

    Full Text Available Background: This investigation was conducted in order to study angiographic findings in patients with cerebral aneurysm. Materials and Methods: The study conducted on 136 cases of ruptured cerebral aneurysms between 1995-2000 confirmed by means of 4-vessel cerebral angiography to get an insight to racial, geographic and environmental factors predisposing to the occurrence of subarachnoid hemorrhage and aneurysm formation. Results: The data analysis revealed the following results: 58% of the population comprised of male and 42% female with a mean age of 46 years. 89% of the aneurysms were found in the anterior circulation and 11% occurred in the posterior cerebral circulation. The most common site in both the sexes was the anterior communicating artery. 9.6% of the patients displayed two separate aneurysms. 5.2% of the aneurysms were found to be giant aneurysms and 3% of the patients had fusiform aneurysms. Conclusion: The low average age, a predilection in male population and the prevalence of aneurysms at carotid and middle cerebral artery bifurcation and the distal branches of anterior cerebral artery and a higher incidence of anterior communicating artery in women were the findings observed in this study.

  2. The seismic response of concrete arch bridges (with focus on the Bixby Creek bridge Carmel, California)

    Energy Technology Data Exchange (ETDEWEB)

    Hoehler, M; McCallen, D; Noble, C

    1999-06-01

    The analysis, and subsequent retrofit, of concrete arch bridges during recent years has relied heavily on the use of computational simulation. For seismic analysis in particular, computer simulation, typically utilizing linear approximations of structural behavior, has become standard practice. This report presents the results of a comprehensive study of the significance of model sophistication (i.e. linear vs. nonlinear) and pertinent modeling assumptions on the dynamic response of concrete arch bridges. The study uses the Bixby Creek Bridge, located in California, as a case study. In addition to presenting general recommendations for analysis of this class of structures, this report provides an independent evaluation of the proposed seismic retrofit for the Bixby Creek Bridge. Results from the study clearly illustrate a reduction of displacement drifts and redistribution of member forces brought on by the inclusion of material nonlinearity. The analyses demonstrate that accurate modeling of expansion joints, for the Bixby Creek Bridge in particular, is critical to achieve representative modal and transient behavior. The inclusion of near-field displacement pulses in ground motion records was shown to significantly increase demand on the relatively softer, longer period Bixby Creek Bridge arch. Stiffer, shorter period arches, however, are more likely susceptible to variable support motions arising from the canyon topography typical for this class of bridges.

  3. Towards Predicting Patient-Specific Flow-Diverter Treatment Outcomes for Bifurcation Aneurysms: From Implantation Rehearsal to Virtual Angiograms.

    Science.gov (United States)

    Peach, T W; Spranger, K; Ventikos, Y

    2016-01-01

    Despite accounting for the majority of all cerebral aneurysm cases, bifurcation aneurysms present many challenges to standard endovascular treatment techniques. This study examines the treatment of bifurcation aneurysms endovascularly with flow-diverting stents and presents an integrative computational modeling suite allowing for rehearsing all aspects of the treatment. Six bifurcation aneurysms are virtually treated with 70% porosity flow-diverters. Substantial reduction (>50%) in aneurysm inflow due to device deployment is predicted in addition to reductions in peak and average aneurysm wall shear stress to values considered physiologically normal. The subsequent impact of flow-diverter deployment on daughter vessels that are jailed by the device is investigated further, with a number of simulations conducted with increased outlet pressure conditions at jailed vessels. Increased outlet pressures at jailed daughter vessels are found to have little effect on device-induced aneurysm inflow reduction, but large variation (13-86%) is seen in the resulting reduction in daughter vessel flow rate. Finally, we propose a potentially powerful approach for validation of such models, by introducing an angiographic contrast model, with contrast transport modeled both before and after virtual treatment. Virtual angiograms and contrast residence curves are created, which offer unique clinical relevance and the potential for future in vivo verification of simulated results.

  4. Normal azygos arch: retrotracheal visualization on frontal chest tomograms.

    Science.gov (United States)

    Austin, J H; Thorsen, M K

    1981-12-01

    Anteroposterior, linear tomograms of 78 adult subjects in the supine position revealed visualization of pleural reflections off the retrotracheal part of the normal azygos arch in 38 (49%). The course of the arch varied by about 3 cm. Five distinct patterns were found, mainly depending on the course of the inferior margin of the arch. The inferior margin varied from relatively superior retrotracheal positions to intermediate positions appearing to intersect the carina, to relatively inferior and right-sided positions posterior to the proximal right main bronchus. Recognition of these normal variations of the azygos arch should serve to differentiate them from abnormalities in this region. PMID:6976093

  5. Normal azygos arch: retrotracheal visualization on frontal chest tomograms

    International Nuclear Information System (INIS)

    Anteroposterior, linear tomograms of 78 adult subjects in the supine position revealed visualization of pleural reflections off the retrotracheal part of the normal azygos arch in 38 (49%). The course of the arch varied by about 3 cm. Five distinct patterns were found, mainly depending on the course of the inferior margin of the arch. The inferior margin varied from relatively superior retrotracheal positions to intermediate positions appearing to intersect the carina, to relatively inferior and right-sided positions posterior to the proximal right main bronchus. Recognition of these normal variations of the azygos arch should serve to differentiate them from abnormalities in this region

  6. Normal azygos arch: retrotracheal visualization on frontal chest tomograms

    Energy Technology Data Exchange (ETDEWEB)

    Austin, J.H.M. (Columbia-Presbyterian Medical Center, New York); Thorsen, M.K.

    1981-12-01

    Anteroposterior, linear tomograms of 78 adult subjects in the supine position revealed visualization of pleural reflections off the retrotracheal part of the normal azygos arch in 38 (49%). The course of the arch varied by about 3 cm. Five distinct patterns were found, mainly depending on the course of the inferior margin of the arch. The inferior margin varied from relatively superior retrotracheal positions to intermediate positions appearing to intersect the carina, to relatively inferior and right-sided positions posterior to the proximal right main bronchus. Recognition of these normal variations of the azygos arch should serve to differentiate them from abnormalities in this region.

  7. Pulmonary artery aneurysm with patent arterial duct: resection of aneurysm and ductal division.

    Science.gov (United States)

    Tefera, Endale; Teodori, Michael

    2013-10-01

    Congenital or acquired aneurysm of the pulmonary artery (PA) is rare. Although aneurysms are described following surgical treatment of patent ductus arteriosus (PDA), occurrence of this lesion in association with PDA without previous surgery is extremely uncommon. An eight-year-old patient with PDA and aneurysm of the main PA is described in this report. Clinical diagnosis of PDA was made upon presentation. Diagnosis of PA aneurysm was suspected on chest x-ray and was confirmed on transthoracic echocardiography. Successful surgical resection of the aneurysm and division of the duct were performed under cardiopulmonary bypass. The patient did well on follow-up both from clinical and echocardiographic point of view.

  8. Study on multi-scheme analysis and evaluation method for concrete sequence placement of high arch dam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A complete scheme for solving the key scientific problems of how to make concrete sequence placement scheme of high arch dam reasonable and feasible and how to meet the need of construction process was presented.First,based on a coupling analysis of concrete sequence placement system of high arch dam,a mathematical model considering complex construction constraints was established.Second,a multi-scheme computational analysis method for concrete sequence placement of high arch dam was proposed based on dynamic simulation.Third,a multi-scheme evaluation method for concrete sequence placement was put forward based on analytic hierarchy process.Fourth,feedback guidance for progress control and management in the high arch dam construction process was proposed.Finally,these methods were applied to a practical project to show that the methods can analyze and evaluate multi-scheme for concrete sequence placement of high arch dam effectively,optimize the process of dam concrete sequence placement,and recommend engineering measures.These methods provide new theoretical principles and technical measures for real-time progress control in the high arch dam construction.

  9. 3D image analysis of abdominal aortic aneurysm

    Science.gov (United States)

    Subasic, Marko; Loncaric, Sven; Sorantin, Erich

    2002-05-01

    This paper presents a method for 3-D segmentation of abdominal aortic aneurysm from computed tomography angiography images. The proposed method is automatic and requires minimal user assistance. Segmentation is performed in two steps. First inner and then outer aortic border is segmented. Those two steps are different due to different image conditions on two aortic borders. Outputs of these two segmentations give a complete 3-D model of abdominal aorta. Such a 3-D model is used in measurements of aneurysm area. The deformable model is implemented using the level-set algorithm due to its ability to describe complex shapes in natural manner which frequently occur in pathology. In segmentation of outer aortic boundary we introduced some knowledge based preprocessing to enhance and reconstruct low contrast aortic boundary. The method has been implemented in IDL and C languages. Experiments have been performed using real patient CTA images and have shown good results.

  10. Measuring medial longitudinal arch deformation during gait. A reliability study

    DEFF Research Database (Denmark)

    Bencke, Jesper; Christiansen, Ditte; Jensen, Anne Kathrine Bendrup;

    2012-01-01

    Clinical evaluation of medial longitudinal arch deformation (MLAD) during walking gait is often estimated from static measures of e.g. navicular drop (ND) measured during quiet standing. The aim of the present study was to test the reliability of a new three-dimensional method of measuring the MLAD...... during gait and to compare this method with a static measure and a 2D dynamic method. Fifty-two feet (26 healthy male participants) were tested twice 4-9 days apart in a biomechanical gait analysis laboratory using a 3D three-marker foot model, a 2D video-based model for the measurement of MLAD during...... and showed that ND obtained during quiet standing could not predict the MLAD during gait. The 3D method, or alternatively the 2D method, may be used in clinical settings as reliable methods for easy estimation of the foot longitudinal stability....

  11. Accuracy and reproducibility of patient-specific hemodynamic models of stented intracranial aneurysms: report on the Virtual Intracranial Stenting Challenge 2011.

    Science.gov (United States)

    Cito, S; Geers, A J; Arroyo, M P; Palero, V R; Pallarés, J; Vernet, A; Blasco, J; San Román, L; Fu, W; Qiao, A; Janiga, G; Miura, Y; Ohta, M; Mendina, M; Usera, G; Frangi, A F

    2015-01-01

    Validation studies are prerequisites for computational fluid dynamics (CFD) simulations to be accepted as part of clinical decision-making. This paper reports on the 2011 edition of the Virtual Intracranial Stenting Challenge. The challenge aimed to assess the reproducibility with which research groups can simulate the velocity field in an intracranial aneurysm, both untreated and treated with five different configurations of high-porosity stents. Particle imaging velocimetry (PIV) measurements were obtained to validate the untreated velocity field. Six participants, totaling three CFD solvers, were provided with surface meshes of the vascular geometry and the deployed stent geometries, and flow rate boundary conditions for all inlets and outlets. As output, they were invited to submit an abstract to the 8th International Interdisciplinary Cerebrovascular Symposium 2011 (ICS'11), outlining their methods and giving their interpretation of the performance of each stent configuration. After the challenge, all CFD solutions were collected and analyzed. To quantitatively analyze the data, we calculated the root-mean-square error (RMSE) over uniformly distributed nodes on a plane slicing the main flow jet along its axis and normalized it with the maximum velocity on the slice of the untreated case (NRMSE). Good agreement was found between CFD and PIV with a NRMSE of 7.28%. Excellent agreement was found between CFD solutions, both untreated and treated. The maximum difference between any two groups (along a line perpendicular to the main flow jet) was 4.0 mm/s, i.e. 4.1% of the maximum velocity of the untreated case, and the average NRMSE was 0.47% (range 0.28-1.03%). In conclusion, given geometry and flow rates, research groups can accurately simulate the velocity field inside an intracranial aneurysm-as assessed by comparison with in vitro measurements-and find excellent agreement on the hemodynamic effect of different stent configurations.

  12. Aneurysmal subarachnoid hemorrhage: outcome of aneurysm clipping versus coiling in anterior circulation aneurysm

    International Nuclear Information System (INIS)

    To compare the neurological outcome of microsurgical clipping versus coiling in patients with anterior circulation aneurysm. Study Design: Comparative study. Place and Duration of Study: Department of Neurosurgery, Lahore General Hospital, Lahore, from January 2010 to December 2013. Methodology: Patients aged 14 - 60 years, with ruptured cerebral aneurysm of anterior circulation and World Federation of Neurosurgical Society (WFNS) grades 1, 2 and 3 were included. Patients more than 60 years, medically unfit patient and posterior circulation aneurysms and WFNS grades 4 and 5 were excluded. Aneurysm sac obliteration was done in randomized manner with microsurgical clipping or coiling. Postoperatively, the patients were assessed and followed-up upto one year for outcome parameters on the bases of WFNS grade and Modified Ranking Scale (mRS) as favourable (mRS =2 ) and unfavourable (mRS > 2). Results: Among 140 subjects selected for study, 70 were included in group A, i.e. coiling and other 70 were in group B, i.e. clipping. The median age of patients in group A was 52.5 ± 10 years and in group B was 51.00 ± years. Overall, 56 (40%) males, 28 (60%) males in each group; and 84 (60%) females, 42 (60%) in each group were included. The male to female ratio in this study was 1:1.5. In group A, i.e. coiling, 27 (38.6%) patients had no disability (grades 1 and 2), 25 (35.7%) were slightly disabled (grade 3) and 18 (25.7%) had moderate disability (grade 4); whereas in group B, i.e. clipping group 23 (32.9%) patients had no disability (grades 1 and 2), 23 (32.9%) were slightly disabled (grade 3) and 24 (34.3%) had moderate disability (grade 4). At one year follow-up, in group A, favourable outcome was achieved in 56 (80%) of patients compared to 48 (68.6%) in group B; whilst, 14 (20%) patients in group A and 22 (33.1%) in group B showed unfavourable outcome. Although mortality rate was higher in clipping (n=3, 4.3%) as compared to coiling (n=1, 1.4%), but was not statistically

  13. Three-dimensional measurement of foot arch in preschool children

    Directory of Open Access Journals (Sweden)

    Chang Hsun-Wen

    2012-09-01

    Full Text Available Abstract Background The prevalence of flexible flatfoot is high among preschool-aged children, but the effects of treatment are inconclusive due to the unclear definitions of normal flatfoot. To date, a universally accepted evaluation method of the foot arch in children has not been completely established. Our aims of this study were to establish a new method to evaluate the foot arch from a three dimensional perspective and to investigate the flexibility of the foot arch among children aged from two to six. Methods A total of 44 children aged from two to six years of age were put into five age groups in this study. The navicular height was measured with one leg standing, and both feet were scanned separately in both sitting and one leg standing positions to compute the foot arch volume. The arch volume index, which represents the ratio of the difference in volume between sitting and one leg standing positions to the volume when sitting was calculated to demonstrate the flexibility of the foot arch. The differences of measured parameters between each aged group were analyzed by one-way ANOVA. Results The arch volumes when sitting and standing were highly correlated with the navicular height. The navicular height ranged from 15.75 to 27 mm, the arch volume when sitting ranged from 6,223 to 11,630 mm3, and the arch volume when standing from 3,111 to 7,848 mm3 from two to six years of age. The arch volume index showed a declining trend as age increased. Conclusion This study is the first to describe the foot arch with volume perspective in preschool-aged children. The foot arch volume was highly correlated with the navicular height. Research results show both navicular height index and arch volume index gradually increase with age from two to six. At the same time the arch also becomes rigid with age from two to six. These results could be applied for clinical evaluation of the foot arch and post-treatment evaluation.

  14. Idiopathic giant right atrial aneurysm

    International Nuclear Information System (INIS)

    A 2-year-old boy with an incidental finding of massive cardiomegaly on a chest X-ray was diagnosed with a giant right atrial aneurysm upon further investigation with echocardiography. The patient underwent successful surgical reduction of the right atrium and closure of the patent foramen ovale to prevent thromboembolic complications and to lower the risk of atrial arrhythmias. The resected atrium had paper-thin walls and pathological features of interstitial fibrosis with endocardial thickening

  15. Familial Abdominal Aortic Aneurysm : Clinical Features and Genetics

    NARCIS (Netherlands)

    K.M. van de Luijtgaarden (Koen)

    2016-01-01

    markdownabstractAbstract Cardiovascular disease is the most important cause of death in the world and encompasses occlusive as well as aneurysmal disease. The most common aneurysm in humans is the abdominal aortic aneurysm (AAA). The question is why the aorta dilates in aneurysmal disease and occ

  16. Preemptive Medicine for Cerebral Aneurysms

    Science.gov (United States)

    AOKI, Tomohiro; NOZAKI, Kazuhiko

    2016-01-01

    Most of cerebral aneurysms (CAs) are incidentally discovered without any neurological symptoms and the risk of rupture of CAs is relatively higher in Japanese population. The goal of treatments for patients with CAs is complete exclusion of the aneurysmal rupture risk for their lives. Since two currently available major treatments, microsurgical clipping and endovascular coiling, have inherent incompleteness to achieve cure of CAs with some considerable treatment risks, and there is no effective surgical or medical intervention to inhibit the formation of CAs in patients with ruptured and unruptured CAs, new treatment strategies with lower risk and higher efficacy should be developed to prevent the formation, growth, and rupture of CAs. Preemptive medicine for CAs should be designed to prevent or delay the onset of symptoms from CAs found in an asymptomatic state or inhibit the de novo formation of CAs, but we have no definite methods to distinguish rupture-prone aneurysms from rupture-resistant ones. Recent advancements in the research of CAs have provided us with some clues, and one of the new treatment strategies for CAs will be developed based on the findings that several inflammatory pathways may be involved in the formation, growth, and rupture of CAs. Preemptive medicine for CAs will be established with specific biomarkers and imaging modalities which can sensor the development of CAs. PMID:27053328

  17. Including Functional Annotations and Extending the Collection of Structural Classifications of Protein Loops (ArchDB

    Directory of Open Access Journals (Sweden)

    Antoni Hermoso

    2007-01-01

    Full Text Available Loops represent an important part of protein structures. The study of loop is critical for two main reasons: First, loops are often involved in protein function, stability and folding. Second, despite improvements in experimental and computational structure prediction methods, modeling the conformation of loops remains problematic. Here, we present a structural classification of loops, ArchDB, a mine of information with application in both mentioned fields: loop structure prediction and function prediction. ArchDB (http://sbi.imim.es/archdb is a database of classified protein loop motifs. The current database provides four different classification sets tailored for different purposes. ArchDB-40, a loop classification derived from SCOP40, well suited for modeling common loop motifs. Since features relevant to loop structure or function can be more easily determined on well-populated clusters, we have developed ArchDB-95, a loop classification derived from SCOP95. This new classification set shows a ∼40% increase in the number of subclasses, and a large 7-fold increase in the number of putative structure/function-related subclasses. We also present ArchDB-EC, a classification of loop motifs from enzymes, and ArchDB-KI, a manually annotated classification of loop motifs from kinases. Information about ligand contacts and PDB sites has been included in all classification sets. Improvements in our classification scheme are described, as well as several new database features, such as the ability to query by conserved annotations, sequence similarity, or uploading 3D coordinates of a protein. The lengths of classified loops range between 0 and 36 residues long. ArchDB offers an exhaustive sampling of loop structures. Functional information about loops and links with related biological databases are also provided. All this information and the possibility to browse/query the database through a web-server outline an useful tool with application in the

  18. Update on diagnosis and treatment of cardiac pseudo aneurysm

    International Nuclear Information System (INIS)

    Echocardiography is an essential tool in the diagnosis of pseudo aneurysm. It has been the most studied in diagnosing this condition.The M, two-dimensional and Doppler apply to reach a correct diagnosis of ventricular pseudo aneurysm. The use of this imaging technique allows noninvasive detection of asymptomatic or postoperative pseudo aneurysms after M mode used to diagnose a pseudo aneurysm to recognize an echo-free space in the posterior wall of the left ventricle. In 1980, Catherwood et al used to compare the two-dimensional echo pseudo aneurysm and a true aneurysm cavity demonstrated pseudo aneurysm globular and discontinuity of the ventricular myocardium

  19. Analysis of slipstream flow in two ruptured intracranial cerebral aneurysms.

    Science.gov (United States)

    Imbesi, S G; Kerber, C W

    1999-10-01

    Replicas of ruptured posterior communicating and basilar artery aneurysms were created from cadaveric specimens and then were placed in a circuit of pulsating non-Newtonian fluid. Individual fluid slipstreams were opacified with isobaric dyes, and images were recorded on film. The slipstreams entered the distal aneurysm neck with impact against the distal lateral wall of the aneurysm. They then swirled slowly in a reverse vortical pattern within the aneurysm sac. Fluid exited the aneurysm at the proximal neck. The flow pattern clearly shows the impact zone of entering slipstreams (the point of aneurysm rupture) and provides information pertaining to aneurysm growth and formation. PMID:10543644

  20. Ant Colony Optimization Analysis on Overall Stability of High Arch Dam Basis of Field Monitoring

    OpenAIRE

    Peng Lin; Xiaoli Liu; Hong-Xin Chen; Jinxie Kim

    2014-01-01

    A dam ant colony optimization (D-ACO) analysis of the overall stability of high arch dams on complicated foundations is presented in this paper. A modified ant colony optimization (ACO) model is proposed for obtaining dam concrete and rock mechanical parameters. A typical dam parameter feedback problem is proposed for nonlinear back-analysis numerical model based on field monitoring deformation and ACO. The basic principle of the proposed model is the establishment of the objective function o...

  1. Migraine before rupture of intracranial aneurysms

    DEFF Research Database (Denmark)

    Lebedeva, Elena R; Gurary, Natalia M; Sakovich, Vladimir P;

    2013-01-01

    Rupture of a saccular intracranial aneurysm (SIA) causes thunderclap headache but it remains unclear whether headache in general and migraine in particular are more prevalent in patients with unruptured SIA.......Rupture of a saccular intracranial aneurysm (SIA) causes thunderclap headache but it remains unclear whether headache in general and migraine in particular are more prevalent in patients with unruptured SIA....

  2. Two cases of giant serpentine aneurysm.

    Science.gov (United States)

    Kumabe, T; Kaneko, U; Ishibashi, T; Kaneko, K; Uchigasaki, S

    1990-06-01

    Giant serpentine aneurysm (GSA) is an entity defined on radiological and pathological grounds as a giant, partially thrombosed aneurysm containing tortuous vascular channels. We have had the opportunity to study two patients with GSAs, which has allowed for a complete comparative anatomical and radiological study. This report emphasizes the etiology of the GSAs. Twenty-two patients with GSAs have been reported in the literature, of which pathological studies were done in 10. In most of these, the aneurysm was found to be filled with an organized thrombus, but in our patients the aneurysm was filled with relatively new clot. The aneurysm enlarged and a change in the tortuous vascular channel was observed over a period of 1 year in the first patient, whereas a globoid aneurysm developed into a GSA in the brief period of just 2 weeks in the second patient. This rapid transformation of a globoid aneurysm into a GSA is of particular interest when the etiology of GSAs is considered. Our patients therefore shed some interesting light on the possible pathophysiology of GSAs. That is, the bloodstream may change dynamically in a giant aneurysm and may become a serpentine channel under conditions that lead to a "Coanda effect." PMID:2362659

  3. Celiac trunk coverage in endovascular aneurysm repair

    DEFF Research Database (Denmark)

    Delle, Martin; Lönn, Lars; Henrikson, O;

    2010-01-01

    This retrospective study was undertaken to examine the risks associated with obstruction of the coeliac trunk in the process of treating aneurysms with endografting.......This retrospective study was undertaken to examine the risks associated with obstruction of the coeliac trunk in the process of treating aneurysms with endografting....

  4. [A cylinder aneurysm of a penile prosthesis].

    Science.gov (United States)

    Pannek, J; Bartel, P; Göcking, K

    2011-07-01

    Herniation of a penile prosthesis (cylinder aneurysm) is an extremely rare complication of penile prosthesis surgery. We report the first case of such an aneurysm in a patient with spinal cord injury. The treatment of choice is surgical revision with replacement of the faulty device. Filling of the implanted system with contrast media facilitates preoperative diagnostic workup. PMID:21567276

  5. Growth rates of intracranial aneurysms : exploring constancy

    NARCIS (Netherlands)

    Koffijberg, Hendrik; Buskens, Erik; Algra, Ale; Wermer, Marieke J. H.; Rinkel, Gabriel J. E.

    2008-01-01

    Object. The annual rate of rupture of intracranial aneurysms is often assumed to be constant, but it is unknown whether this assumption is true. Recent case reports have suggested that aneurysms grow fast in a short period of time. The authors of the present report investigated the plausibility of a

  6. Natural history of abdominal aortic aneurysm

    DEFF Research Database (Denmark)

    Perko, M J; Schroeder, T V; Olsen, P S;

    1993-01-01

    .53, corresponding to an annual risk of 30%. Diameter of the aneurysm was found to be the only factor with a significant impact on the rate of rupture. The cumulative 5-year hazard rate of rupture among patients with aneurysms cm and > or = 6 cm was 0.2 and 0.6, respectively, corresponding to an annual risk...

  7. HADRIAN’S ARCHES FROM ROMAN PERIOD, JORDAN: A COMPARATIVE STUDY

    OpenAIRE

    Nassar, Mohammad

    2014-01-01

    This article provides a study of Hadrian arches from three main locations: Jordan, Turkey, and Greece. Collectively within these countries, four arches have been found the Hadrian arch at Jerash (Gerasa) in Jordan, the Hadrian arch in Antalya and Ephesus, both in Turkey, and the Hadrian arch in Athens, Greece. The units of our analysis include all the different designs and plans used in constructing these arches. The analyzed design and planning units constitute a database that enables the...

  8. The Evolution of Protoplanetary Discs in the Arches Cluster

    CERN Document Server

    Olczak, C; Harfst, S; Pfalzner, S; Zwart, S Portegies

    2012-01-01

    Most stars form in a cluster environment. These stars are initially surrounded by discs from which potentially planetary systems form. Of all cluster environments starburst clusters are probably the most hostile for planetary systems in our Galaxy. The intense stellar radiation and extreme density favour rapid destruction of circumstellar discs via photoevaporation and stellar encounters. Evolving a virialized model of the Arches cluster in the Galactic tidal field we investigate the effect of stellar encounters on circumstellar discs in a prototypical starburst cluster. Despite its proximity to the deep gravitational potential of the Galactic centre only a moderate fraction of members escapes to form an extended pair of tidal tails. Our simulations show that encounters destroy one third of the circumstellar discs in the cluster core within the first 2.5 Myr of evolution, preferentially affecting the least and most massive stars. A small fraction of these events causes rapid ejection and the formation of a we...

  9. Mechanical stress in abdominal aortic aneurysms using artificial neural networks

    OpenAIRE

    Soudah Prieto, Eduardo; Rodriguez, Jose; López González, Roberto

    2015-01-01

    Combination of numerical modeling and artificial intelligence (AI) in bioengineering processes are a promising pathway for the further development of bioengineering sciences. The objective of this work is to use Artificial Neural Networks (ANN) to reduce the long computational times needed in the analysis of shear stress in the Abdominal Aortic Aneurysm (AAA) by finite element methods (FEM). For that purpose two different neural networks are created. The first neural network (Mesh Neural Netw...

  10. Adult presentation with vascular ring due to double aortic arch.

    Science.gov (United States)

    Kafka, Henryk; Uebing, Anselm; Mohiaddin, Raad

    2006-11-01

    This is a case report on the use of cardiovascular magnetic resonance imaging to diagnose vascular ring due to double aortic arch in an adult presenting with an abnormal chest X-ray. The experience in this case and the literature review identify the benefits of using cardiovascular magnetic resonance imaging to clarify complex aortic arch anatomy.

  11. Double aortic arch and nasogastric tubes: A fatal combination

    Institute of Scientific and Technical Information of China (English)

    Julia Massaad; Kelly Crawford

    2008-01-01

    Double aortic arch is a common form of complete vascular ring that encircles both the trachea and the esophagus, and presents with various respiratory and esophageal symptoms, usually in the pediatric population.We present a case of double aortic arch in an adult patient that manifested as massive upper gastrointestinal bleeding after prolonged nasogastric intubation.

  12. Swallowing threshold parameters of subjects with shortened dental arches.

    NARCIS (Netherlands)

    Kreulen, C.M.; Witter, D.J.; Tekamp, F.A.; Slagter, A.P.; Creugers, N.H.J.

    2012-01-01

    OBJECTIVES: To quantify swallowing threshold parameters of subjects with a moderate shortened dental arch dentition (SDA: missing molar teeth, but premolar teeth in occluding position and uninterrupted anterior regions) compared to subjects with a complete dental arch dentition (CDA). METHODS: Fourt

  13. Aortic arch vessel anomalies associated with persistent trigeminal artery.

    Science.gov (United States)

    Lotfi, Mehrzad; Nabavizadeh, Seyed Ali; Foroughi, Amin Abolhasani

    2012-01-01

    Developmental anomalies of the aortic arch vessels and persistent trigeminal artery that is the most common of the four anomalous carotid-basilar anastomoses are repeatedly reported in the literature as separate entities. Herein we report a previously undescribed variant including the coexistence of persistent trigeminal artery, truncus bicaroticus and direct origin of left vertebral artery from aortic arch. PMID:22542381

  14. 针梁横向滑模台车在长大隧洞弧形底拱衬砌中的应用%Application of Needle Beam Carriage with Transverse Sliding Model in Construction of Curved Bottom Arch Lining of Long and Large Diversion Tunnel

    Institute of Scientific and Technical Information of China (English)

    陈拥军

    2015-01-01

    During the construction of curved bottom arch lining in long and large diversion tunnels,common problems like air bubble and blister difficult to discharge,and the very poor appearance are found.Through the study on curved bottom arch lining in No.1 diversion tunnel of Jinping-Ⅱ hydropower station,this article discusses the design ideas,structural compositions,key construction technologies of the needle beam carriage with transverse sliding model.The practical field application shows that the relative sophisticated carriage can not only ensure the concrete lining quality,but also greatly im-prove the construction efficiency.%长大隧洞弧形底拱衬砌施工,存在气泡、水泡难以排出,外观质量差的通病。通过对锦屏二级水电站1#引水隧洞弧形底拱衬砌的研究,介绍了针梁横向滑模台车的设计思路、结构组成、关键施工技术等,经过现场实际应用,该台车不仅能够保证衬砌施工质量,而且可以大大提高施工效率,具有一定的先进性。

  15. Optimization design of foundation excavation for Xiluodu super-high arch dam in China

    Directory of Open Access Journals (Sweden)

    Qixiang Fan

    2015-04-01

    Full Text Available With better understanding of the quality and physico-mechanical properties of rocks of dam foundation, and the physico-mechanical properties and structure design of arch dam in association with the foundation excavation of Xiluodu arch dam, the excavation optimization design was proposed for the foundation surface on the basis of feasibility study. Common analysis and numerical analysis results demonstrated the feasibility of using the weakly weathered rocks III1 and III2 as the foundation surface of super-high arch dam. In view of changes in the geological conditions at the dam foundation along the riverbed direction, the design of extending foundation surface excavation area and using consolidating grouting and optimizing structure of dam bottom was introduced, allowing for harmonization of the arch dam and foundation. Three-dimensional (3D geomechanics model test and finite element analysis results indicated that the dam body and foundation have good overload stability and high bearing capacity. The monitoring data showed that the behaviors of dam and foundation correspond with the designed patterns in the construction period and the initial operation period.

  16. Multimodal optical measurement in vitro of surface deformations and wall thickness of the pressurized aortic arch.

    Science.gov (United States)

    Genovese, Katia; Humphrey, Jay D

    2015-04-01

    Computational modeling of arterial mechanics continues to progress, even to the point of allowing the study of complex regions such as the aortic arch. Nevertheless, most prior studies assign homogeneous and isotropic material properties and constant wall thickness even when implementing patient-specific luminal geometries obtained from medical imaging. These assumptions are not due to computational limitations, but rather to the lack of spatially dense sets of experimental data that describe regional variations in mechanical properties and wall thickness in such complex arterial regions. In this work, we addressed technical challenges associated with in vitro measurement of overall geometry, full-field surface deformations, and regional wall thickness of the porcine aortic arch in its native anatomical configuration. Specifically, we combined two digital image correlation-based approaches, standard and panoramic, to track surface geometry and finite deformations during pressurization, with a 360-deg fringe projection system to contour the outer and inner geometry. The latter provided, for the first time, information on heterogeneous distributions of wall thickness of the arch and associated branches in the unloaded state. Results showed that mechanical responses vary significantly with orientation and location (e.g., less extensible in the circumferential direction and with increasing distance from the heart) and that the arch exhibits a nearly linear increase in pressure-induced strain up to 40%, consistent with other findings on proximal porcine aortas. Thickness measurements revealed strong regional differences, thus emphasizing the need to include nonuniform thicknesses in theoretical and computational studies of complex arterial geometries.

  17. Optimization design of foundation excavation for Xiluodu super-high arch dam in China

    Institute of Scientific and Technical Information of China (English)

    Qixiang Fan; Shaowu Zhou; Ning Yang

    2015-01-01

    With better understanding of the quality and physico-mechanical properties of rocks of dam foundation, and the physico-mechanical properties and structure design of arch dam in association with the foun-dation excavation of Xiluodu arch dam, the excavation optimization design was proposed for the foundation surface on the basis of feasibility study. Common analysis and numerical analysis results demonstrated the feasibility of using the weakly weathered rocks III1 and III2 as the foundation surface of super-high arch dam. In view of changes in the geological conditions at the dam foundation along the riverbed direction, the design of extending foundation surface excavation area and using consolidating grouting and optimizing structure of dam bottom was introduced, allowing for harmonization of the arch dam and foundation. Three-dimensional (3D) geomechanics model test and finite element analysis re-sults indicated that the dam body and foundation have good overload stability and high bearing capacity. The monitoring data showed that the behaviors of dam and foundation correspond with the designed patterns in the construction period and the initial operation period.

  18. Earthquake analysis of arch and gravity dams including the effects of foundation inhomogeneity

    Institute of Scientific and Technical Information of China (English)

    LIN Gao; DU Jianguo; HU Zhiqiang

    2007-01-01

    Dam-foundation interaction plays an important role in the design of earthquake-resistant concrete arch and gravity dams.Geological conditions of the dam canyon are usually very complicated;however,in the literature,the damfoundation interaction analysis is often carried out based on the premise of a homogeneous unbounded foundation.In this paper,the effect of foundation inhomogeneity on the seismic response of arch and gravity dams was studied by means of scaled boundary finite element method (SBFEM).In order to satisfy the similarity requirement of SBFEM and simplify the computational effort,a subdomain approach and a conical representation of an unbounded foundation were proposed.The way of partitioning the domain and the selection of open angle and bottom radius of the cone model on the accuracy of the result were examined.Numerical examples show that the proposed approach is rational and efficient.Cases of foundation inhomogeneity with stiffness varying in accordance with an exponential function along the radial direction,and cases of foundation inhomogeneity with stiffness discontinuity and with weak interlayer strata on the earthquake response of concrete arch dams as well as gravity dams were analyzed.It was found that a homogeneous idealization of the unbounded foundation may sometimes greatly underestimate the maximum earthquake stress response of the dam.Therefore,taking into account the effect of foundation inhomogeneity for the earthquake safety assessment of concrete arch and gravity dams has great significance.

  19. Simultaneous presentation of two cerebral aneurysms.

    Science.gov (United States)

    Yoshida, Masahiro; Ezura, Masayuki; Sasaki, Kazuto; Chonan, Masashi; Mino, Masaki

    2012-01-01

    A 48-year-old woman experienced sudden onset of severe headache. Computed tomography showed subarachnoid hemorrhage (SAH) and intracerebral hematoma in the right frontal lobe. Digital subtraction angiography revealed three aneurysms in the anterior communicating artery (AcomA), the right posterior communicating artery (PcomA), and the right middle cerebral artery. The AcomA aneurysm was treated with endovascular coiling. However, her oculomotor nerve palsy was aggravated after the procedure. Embolization of the right PcomA aneurysm was conducted immediately and her oculomotor nerve palsy recovered completely 3 months later. Simultaneous presentation of multiple aneurysms with separate symptoms is rare. We speculate that the progressive oculomotor nerve palsy was caused by tiny enlargement or morphological change of the aneurysm caused by elevated blood pressure and pulsatile effect after SAH.

  20. Seismic multi-arch structures in East China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In previous papers (Wencai, 2002, 2003), the author has analyzed the deep seismic reflection profiles along some of the Mesozoic plutons in East China, and has pointed out that the crustal structures around these intrusions usually correlate with a special seismic fabric called the seismic multi-arch structure. This paper will continue to show main characteristics of the seismic multi-arch structures and discuss their relationship with mantle-origin magmatism and the lithospheric thinning process. Calibration of seismic reflectors in Chinese continental drilling sites shows that small-scale arch-like reflectors can be generated by fractured eclogites or other plutons, they do not belong to the multi-arch structure specially discussed in the paper. The multi-arch structure is characterized by several arch-like reflectors distributed in both the upper and lower crust with granitoid plutons or stocks exposed on the surface, which do not have obvious negative Europium anomalies. Based on the distribution pattern of arch reflectors, the multi-arch magmatic structures can be divided into three main types, namely the simple vertical combination type, the spread arch magmatic structure and the arch-bouquet structure. All of them correlate to mantle-origin magmatism, but occur in different places. The spread arch magmatic structures occur within a Mesozoic/Cenozoic rift zone with very thin and hot lithosphere. The vertical combination type of the multi-arch structures occurred near the rift zones where lithosphere was thin and hot. The arch-bouquet magmatic structures occur far from the rift zones where the lithosphere is not hot. The continental rifting acted as the late episode of the lithospheric thinning process seeing that the rift zones usually coincide with the thinnest parts of the lithosphere in East China. In different locations within the lithospheric thinning areas, mantle-origin magmatic activities have different characteristics, which might generate different

  1. Disappearing Saccular Intracranial Aneurysms: Do They Really Disappear?

    OpenAIRE

    Jayakumar, P. N.; Ravishankar, S.; Balasubramaya, K.S.; Chavan, R.; Goyal, G

    2007-01-01

    Evolution and natural history of cerebral aneurysms is a dynamic process. Spontaneous regression in size or complete disappearance of an aneurysm is a known phenomenon, more commonly noted in giant intracranial aneurysms. However, reappearance or regrowth of such aneurysms is rare with few anecdotal reports. We report a series of four cases including one giant aneurysm, which either disappeared or regressed on sequential angiograms. Regrowth or reappearance of two of these previously disappea...

  2. [Aneurysm of the anterior inferior cerebellar artery: case report].

    Science.gov (United States)

    Adorno, Juan Oscar Alarcón; de Andrade, Guilherme Cabral

    2002-12-01

    The intracranial aneurysms of the posterior circulation have been reported between 5 and 10% of all cerebral aneurysms and the aneurysms of the anterior inferior cerebellar artery (AICA) are considered rare, can cause cerebello pontine angle (CPA) syndrome with or without subarachnoid hemorrhage. Since 1948 few cases were described in the literature. We report on a 33 year-old female patient with subarachnoid hemorrhage due to sacular aneurysm of the left AICA. She was submitted to clipage of the aneurysm without complications.

  3. Large and giant intracranial aneurysms: A radiologico-clinical study

    Energy Technology Data Exchange (ETDEWEB)

    Lovrencic, M.; Jelicic, I.; Jakovac, I.; Kalousek, M.; Besenski, N.; Surdonja, P.

    1983-12-01

    The brain scans and cerebral angiograms of 13 patients with intracranial aneurysms larger than 15 mm. in diameter are analysed. The radiological findings obtained are compared with clinical symptoms and signs. Twelve patients had genuine aneurysms and one patient a posttraumatic false aneurysm. Post-contrast CT in transversal and coronal plane revealed the real size of the aneurysm in 7 cases of intraluminal thrombosis. Cerebral angiography demonstrated the presence of aneurysms, their anatomic relations and haemodynamic changes.

  4. Left testicular artery arching over the ipsilateral renal vein

    Institute of Scientific and Technical Information of China (English)

    Munekazu Naito; Hayato Terayama; Yoichi Nakamura; Shogo Hayashi; Takayoshi Miyaki; Masahiro Itoh

    2006-01-01

    Aim: To report two cases of the left testicular artery arching over the left renal vein (LRV) before running downward to the testis. Methods: The subjects were obtained from two Japanese cadavers. During the student course of gross-anatomical dissection, the anatomical relationship between the testicular vessels and the renal vein was specifically observed. Results: The arching left testicular artery arose from the aorta below the LRV and made a loop around the LRV, which appeared to be mildly compressed between the arching artery and the psoas major muscle.Conclusion: Clinically, compression of the LRV between the abdominal aorta and the superior mesenteric artery occasionally induces LRV hypertension, resulting in varicocele, orthostatic protenuria and hematuria. Considering that the incidence of a left arching testicular artery is higher than that of a right one, an arching left artery could be an additional cause of LRV hypertension.

  5. Effect of Obesity on Arch Index in Young Adults

    Directory of Open Access Journals (Sweden)

    Sneha Sameer Ganu

    2013-01-01

    Full Text Available Background: Excessive increases in weight bearing forces caused by obesity may negatively affect the lower limbs and feet but minimal research has examined the long-term loading effects of obesity on the musculoskeletal system, particularly in reference to the feet. Objectives: The purpose of the study was to investigate the effect of obesity on medial longitudinal arch of foot in young adults. Method: 60 subjects, 30 obese & 30 non obese were assessed for height & weight using standard technique. Radiographic images under static condition were used for calculating the arch index. Result: The arch index of obese subjects was significantly lower than the non obese subjects & there is a negative correlation between the BMI & the arch index. Conclusion: These results suggests that obesity lowers the medial longitudinal arch of foot.

  6. Clinical trial of doxycycline for matrix metalloproteinase-9 inhibition in patients with an abdominal aneurysm doxycycline selectively depletes aortic wall neutrophils and cytotoxic t cells

    NARCIS (Netherlands)

    Lindeman, J.H.N.; Abdul-Hussien, H.; Bockel, J.H. van; Wolterbeek, R.; Kleemann, R.

    2009-01-01

    Background-Doxycycline has been shown to effectively inhibit aneurysm formation in animal models of abdominal aortic aneurysm. Although this effect is ascribed to matrix metalloproteinase-9 inhibition, such an effect is unclear in human studies. We reevaluated the effect of doxycycline on aortic wal

  7. Hemodynamic simulations in coronary aneurysms of children with Kawasaki disease

    Science.gov (United States)

    Sengupta, Dibyendu; Burns, Jane; Marsden, Alison

    2009-11-01

    Kawasaki disease (KD) is a serious pediatric illness affecting the cardiovascular system. One of the most serious complications of KD, occurring in about 25% of untreated cases, is the formation of large aneurysms in the coronary arteries, which put patients at risk for myocardial infarction. In this project we performed patient specific computational simulations of blood flow in aneurysmal left and right coronary arteries of a KD patient to gain an understanding about their hemodynamics. Models were constructed from CT data using custom software. Typical pulsatile flow waveforms were applied at the model inlets, while resistance and RCR lumped models were applied and compared at the outlets. Simulated pressure waveforms compared well with typical physiologic data. High wall shear stress values are found in the narrow region at the base of the aneurysm and low shear values occur in regions of recirculation. A Lagrangian approach has been adopted to perform particle tracking and compute particle residence time in the recirculation. Our long-term goal will be to develop links between hemodynamics and the risk for thrombus formation in order to assist in clinical decision-making.

  8. Using COMSOL Multiphysics for Biomechanical Analysis of Stent Technology in Cerebral Aneurysms

    DEFF Research Database (Denmark)

    Rasmussen, Joachim; Thyregod, Jesper; Enevoldsen, Marie Sand;

    2009-01-01

    This work presents new fluid-structure interaction (FSI) models in both 2D and 3D of the effect of using vascular stents as treatment of cerebral berry aneurysms. The stent is positioned inside the cerebral artery covering the neck of the aneurysm. The stent is expected to alter the blood flow in...... and strut size, shape, and position are modeled in 2D and 3D FSI models. The models show that pore size and strut shape both have significant influence on stent efficiency....

  9. 3D visualization of strain in abdominal aortic aneurysms based on navigated ultrasound imaging

    Science.gov (United States)

    Brekken, Reidar; Kaspersen, Jon Harald; Tangen, Geir Arne; Dahl, Torbjørn; Hernes, Toril A. N.; Myhre, Hans Olav

    2007-03-01

    The criterion for recommending treatment of an abdominal aortic aneurysm is that the diameter exceeds 50-55 mm or shows a rapid increase. Our hypothesis is that a more accurate prediction of aneurysm rupture is obtained by estimating arterial wall strain from patient specific measurements. Measuring strain in specific parts of the aneurysm reveals differences in load or tissue properties. We have previously presented a method for in vivo estimation of circumferential strain by ultrasound. In the present work, a position sensor attached to the ultrasound probe was used for combining several 2D ultrasound sectors into a 3D model. The ultrasound was registered to a computed-tomography scan (CT), and the strain values were mapped onto a model segmented from these CT data. This gave an intuitive coupling between anatomy and strain, which may benefit both data acquisition and the interpretation of strain. In addition to potentially provide information relevant for assessing the rupture risk of the aneurysm in itself, this model could be used for validating simulations of fluid-structure interactions. Further, the measurements could be integrated with the simulations in order to increase the amount of patient specific information, thus producing a more reliable and accurate model of the biomechanics of the individual aneurysm. This approach makes it possible to extract several parameters potentially relevant for predicting rupture risk, and may therefore extend the basis for clinical decision making.

  10. Model analysis of changes in dental arch width before and after orthodontic treatment with MBT appliance%MBT矫治前后牙弓宽度变化的模型分析研究

    Institute of Scientific and Technical Information of China (English)

    张良

    2012-01-01

    目的 分析牙列拥挤患者不拔牙与拔牙的MBT矫治对牙弓宽度变化的影响.方法 选择我院正畸科2008-2011年MBT矫治器治疗的牙列拥挤患者40例.其中轻中度牙列拥挤患者20例,使用MBT矫治器进行不拔牙正畸;中重度牙列拥挤患者20例,使用MBT矫治器进行拔除4颗第一前磨牙的拔牙正畸.测量术前术后石膏模型的牙弓宽度,对矫治前后不拔牙组和拔牙组的测量数据分别进行组内、组间统计学分析.结果 矫治前后不拔牙组:上颌尖牙间宽度增大,上下颌第一前磨牙、第一磨牙间宽度增大,有统计学意义;拔牙组:上颌尖牙间宽度增大,上下颌第二前磨牙、第一磨牙间宽度变小,有统计学意义.矫治前2组上下颌尖牙、第一磨牙间牙弓宽度相近,无统计学差异;矫治后不拔牙组上下颌第一磨牙间牙弓宽度大于拔牙组,有统计学意义,2组上下颌尖牙间牙弓宽度相近,差异无统计学意义.结论 不拔牙矫治牙弓宽度变化与拥挤部位、拥挤程度有关,拔牙矫治牙弓宽度变化主要与牙齿移动方向有关.拔牙矫治后尖牙间宽度不会减小.%Objective To investigate the changes of dental arch width after extraction and nonextraction treatment with MBT appliance. Methods 40 patients with crowded denture who received treatment with MBT appliance from 2008 to 2011 in our hospital were randomly selected. 20 patients with mild dental crowding who received nonextraction treatment were in the nonextraction group, while 20 patients with severe dental crowding whose 4 first premolars were extracted in the treatment with MBT appliance were in the extraction group. SPSS 11.0 software package was used for paired-samples t Test and independent-samples t Test. Results The upper inter-canine widths, the upper and lower inter-first bicuspid widths, the upper and lower inter-first molar widths of nonextraction cases increased significantly after the treatment. The

  11. Mission archéologique islamique

    Directory of Open Access Journals (Sweden)

    Claire Hardy-Guilbert

    1997-11-01

    Full Text Available La troisième mission exploratoire du programme de recherches archéologiques sur la période islamique au Yémen s'est déroulée du 1 au 22 décembre 1995, en collaboration avec le Dr Ahmad Bataya, et a porté sur la côte méridionale, entre Abyan et Sayhut. Outre une étude approfondie de la ville d'al-Shihr, les prospections ont porté sur les régions d'Abyan, Ahwar et Sayhut. Prospection de la côte : Si Aden-même, le plus grand port yéménite depuis le 10ème siècle, est aujourd'hui trop urba...

  12. 桩网支承路基结构中土拱效应及网垫受力的模型试验研究%Model Study on Arch Effect and Bedding Force of Geosynthetics Reinforced and Pile Supported Embankment

    Institute of Scientific and Technical Information of China (English)

    蔡德钩; 闫宏业; 叶阳升; 张千里; 何华武; 杨生哲

    2011-01-01

    基于相似理论,对桩网支承路基中心土拱效应进行8组模拟试验.测试桩顶轴力、桩土及路基不同高度处应力、格栅拉力和桩间土沉降随路基高度、外荷载变化特性,探讨格栅受力后变形.结果表明:加筋网垫上方竖向应力与以球形拱理论为基础的德国规范计算结果较为接近;加筋网垫下方桩间土承担竖向应力随路基高度、上覆荷载增加而增加;黏性土路基成拱效率略低于砂土路基;对于两层格栅组成的加筋网垫,下层格栅承担土拱效应竖向应力引起拉力大于上层格栅,位于桩帽之间并垂直于桩帽边格栅拉力大于平行于桩帽边格栅拉力;格栅初始松紧状态对土拱成拱效率有一定影响;格栅受力后平面变形形状近似呈悬索状.研究成果可为我国桩网支承路基结构加筋网垫相关规范提供参考.%On the basis of the theory of similarity, eight model experiments have been made to test the arch effect of the geosynthetics reinforced and pile supported embankment (GRPS). The axial force of pile cap, stresses at different heights of the subgrade, tensile force of geosynthetics and inter-pile soil settlement and its variations with different heights of the subgrade and under different external loads have been measured in the course of filling and after filling. Deformations of geosynthetics have been studied. The results show as follows: Vertical stresses above the reinforced bedding are similar to the calculation results of the spherical shape arch method; vertical stresses below the reinforced bedding increase with upward-changing of the subgrade height and the superimposed load; arch forming efficiency of the clay filling material is a little lower than that of sand; for the reinforced bedding consisting of two layers geosynthetics, the tensile forces produced by the arch effect of the lower layer is greater than the upper layer; the tensile forces of the geosynthetics

  13. Longitudinal force in continuously welded rail on long-span tied arch continuous bridge carrying multiple tracks

    Institute of Scientific and Technical Information of China (English)

    YAN Bin; DAI Gong-lian; GUO Wen-hua; XU Qing-yuan

    2015-01-01

    Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube (CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a (77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail (CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load. Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered.

  14. The effect of endoleak on intra-aneurysmal pressure after EVE for abdominal aortic aneurysm

    International Nuclear Information System (INIS)

    Objective: To investigate the intra-aneurysmal pressure curve in the presence of endoleak after endovascular exclusion (EVE) for abdominal aortic aneurysm (AAA). Methods: Infrarenal aortic aneurysms were created with bovine jugular vein segments or patches. Then they were underwent incomplete endovascular exclusion of the aneurysm and formation of endoleaks. The pressures of blood flow outside the graft into the sac were measured. Results: The intrasac pressure was higher than systemic pressure in the presence of endoleak. After sealing the endoleak, pressure decreased significantly, and the pressure cure showed approximately linear. Conclusion: The change of intra-aneurysmal pressure curve reflected the load on aneurysmal wall after EVE, and can also help to determine the endoleak existence

  15. Theoretical and Experimental Investigation of the Nonlinear Behavior of an Electrostatically Actuated In-Plane MEMS Arch

    KAUST Repository

    Ramini, Abdallah H.

    2016-05-02

    We present theoretical and experimental investigation of the nonlinear behavior of a clamped-clamped in-plane MEMS arch when excited by a DC electrostatic load superimposed to an AC harmonic load. Experimentally, a case study of in-plane silicon micromachined arch is examined and its mechanical behavior is measured using optical techniques. An algorithm is developed to extract the various parameters, such as the induced axial force and the initial rise, needed to model the behavior of the arch. A softening spring behavior is observed when the excitation is close to the first resonance frequency due to the quadratic nonlinearity coming from the arch geometry and the electrostatic force. Also, a hardening spring behavior is observed when the excitation is close to the third (second symmetric) resonance frequency due to the cubic nonlinearity coming from mid-plane stretching. Dynamic snap-through behavior is also reported for larger range of electric loads. Theoretically, a multi-mode Galerkin reduced order model is utilized to simulate the arch behavior. General agreement is reported among the theoretical and experimental data.

  16. Complications of endovascular treatment of cerebral aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Orrù, Emanuele, E-mail: surgeon.ema@gmail.com [Neuroradiology Department, Padua University Hospital, Via Giustiniani 2, Padua 35128 (Italy); Roccatagliata, Luca, E-mail: lroccatagliata@neurologia.unige.it [Neuroradiology Department, IRCCS San Martino University Hospital and IST, Largo Rosanna Benzi 10, Genoa 16132 (Italy); Department of Health Sciences (DISSAL), University of Genoa (Italy); Cester, Giacomo, E-mail: giacomo.cester@sanita.padova.it [Neuroradiology Department, Padua University Hospital, Via Giustiniani 2, Padua 35128 (Italy); Causin, Francesco, E-mail: francesco.causin@sanita.padova.it [Neuroradiology Department, Padua University Hospital, Via Giustiniani 2, Padua 35128 (Italy); Castellan, Lucio, E-mail: lucio.castellan@hsanmartino.it [Neuroradiology Department, IRCCS San Martino University Hospital and IST, Largo Rosanna Benzi 10, Genoa 16132 (Italy)

    2013-10-01

    The number of neuroendovascular treatments of both ruptured and unruptured aneurysms has increased substantially in the last two decades. Complications of endovascular treatments of cerebral aneurysms are rare but can potentially lead to acute worsening of the neurological status, to new neurological deficits or death. Some of the possible complications, such as vascular access site complications or systemic side effects associated with contrast medium (e.g. contrast medium allergy, contrast induced nephropathy) can also be encountered in diagnostic angiography. The most common complications of endovascular treatment of cerebral aneurysms are related to acute thromboembolic events and perforation of the aneurysm. Overall, the reported rate of thromboembolic complications ranges between 4.7% and 12.5% while the rate of intraprocedural rupture of cerebral aneurysms is about 0.7% in patients with unruptured aneurysms and about 4.1% in patients with previously ruptured aneurysms. Thromboembolic and hemorrhagic complications may occur during different phases of endovascular procedures and are related to different technical, clinical and anatomic reasons. A thorough knowledge of the different aspects of these complications can reduce the risk of their occurrence and minimize their clinical sequelae. A deep understanding of complications and of their management is thus part of the best standard of care.

  17. Electronic database of arterial aneurysms

    Directory of Open Access Journals (Sweden)

    Fabiano Luiz Erzinger

    2014-12-01

    Full Text Available Background:The creation of an electronic database facilitates the storage of information, as well as streamlines the exchange of data, making easier the exchange of knowledge for future research.Objective:To construct an electronic database containing comprehensive and up-to-date clinical and surgical data on the most common arterial aneurysms, to help advance scientific research.Methods:The most important specialist textbooks and articles found in journals and on internet databases were reviewed in order to define the basic structure of the protocol. Data were computerized using the SINPE© system for integrated electronic protocols and tested in a pilot study.Results:The data entered onto the system was first used to create a Master protocol, organized into a structure of top-level directories covering a large proportion of the content on vascular diseases as follows: patient history; physical examination; supplementary tests and examinations; diagnosis; treatment; and clinical course. By selecting items from the Master protocol, Specific protocols were then created for the 22 arterial sites most often involved by aneurysms. The program provides a method for collection of data on patients including clinical characteristics (patient history and physical examination, supplementary tests and examinations, treatments received and follow-up care after treatment. Any information of interest on these patients that is contained in the protocol can then be used to query the database and select data for studies.Conclusions:It proved possible to construct a database of clinical and surgical data on the arterial aneurysms of greatest interest and, by adapting the data to specific software, the database was integrated into the SINPE© system, thereby providing a standardized method for collection of data on these patients and tools for retrieving this information in an organized manner for use in scientific studies.

  18. Screening for Abdominal Aortic Aneurysm

    OpenAIRE

    Linné, Anneli

    2014-01-01

    Abdominal Aortic Aneurysm (AAA) is a common disease with a prevalence of 1.5-2.0% in 65-year old men in Sweden. The risk of having AAA is increased with smoking, high age, family history of AAA and cardiovascular disease. Women have a lower prevalence (0.5%) and develop AAA later in life. An AAA seldom gives any symptom prior to rupture. Untreated rupture is associated with 100% mortality, while surgically treated rupture is associated with 25-70% mortality. Prophylactic sur...

  19. Nuclear medical diagnostic with ventricular aneurysm

    International Nuclear Information System (INIS)

    In the diagnostic of ventricular aneurysms myocardial scintigraphy and above all radionuclide ventriculography (RNV) have special importance. Because of the non-invasive method and the as a result safe and easy use even with stress studies, RNV can provide a very valuable aid with aneurysm patients in early diagnosis, evaluation of the operability and as well as in the prognosis. It must be noted, however, that the differentiation of multivascular diseases and sometimes ventricular aneurysms can be difficult and the inclusion of an angiocardiograph as a radiological invasive examination procedure seems fitting. (orig./MG)

  20. False iliac artery aneurysm following renal transplantation

    DEFF Research Database (Denmark)

    Levi, N; Sønksen, Jens Otto Reimers; Schroeder, T V;

    1999-01-01

    We report a very rare case of a false iliac artery aneurysm following renal transplantation. The patient was a 51-year-old women who presented with a painful 10 x 10 cm pulsating mass in her left iliac fossa. The patient had received a second cadaveric renal transplantation 5 years previously....... The graft never functioned and transplant nephrectomy was performed 2 weeks later. A CT-scanning showed a 10 x 10 cm large aneurysm arising from the left external iliac artery. At operation a large false aneurysm was identified arising from the original transplant anastomotic site. Due to the extent...

  1. PATIENT-SPECIFIC BLOOD DYNAMIC SIMULATIONS IN ASSESSING ENDOVASCULAR OCCLUSION OF INTRACRANIAL ANEURYSMS

    Institute of Scientific and Technical Information of China (English)

    CHEN Jia-liang; WANG Sheng-zhang; DING Guang-hong; YANG Xin-jian; LI Hai-yun

    2009-01-01

    According to recent studies, there are various potential predictors for surgical outcome for cerebral aneurysms. An accurate surgical outcome assessment would help make better-informed decisions and avoid the risk of rebleeding. It is well known that hemodynamic factors play an important role in the pathogenesis and treatment of intracranial aneurysms. In this article, a computational fluid dynamic analysis is applied to one patient-specific model of the cerebral aneurysm located at the tip of basilar artery, by which the differences of hemodynamic parameters before and after endovascular treatment may be evaluated. Based on the model, we show that the flow behavior near the neck of the aneurysm sees great differences after endovascular treatment as compared with that before treatment, which also affects the wall shear stress and the displacement distribution. In addition, our whole simulation process is based on a series of CFD commercial software packages, which are easily available for doctors to implement such a method in their daily practice. These results would be used to assess the outcome of endovascular treatment for the aneurysm occlusion.

  2. Computational lfuid dynamics simulation of intracranial aneurysms - comparing size and shape

    Institute of Scientific and Technical Information of China (English)

    Zifeng Yang; Hongtao Yu; George P Huang; Ryan Schwieterman; Bryan Ludwig

    2015-01-01

    Objective:To study the hemodynamics of an anatomic internal carotid artery aneurysm derived from a patient-specific model and then manipulate into two phantom morphologies: one growing uniformly by size and the other changing shape unevenly. Methods: The computational model of the saccular, internal carotid artery, aneurysm was constructed from 3D rotational, digitally subtracted, catheter angiography images. Computational fluid dynamics simulations were performed under pulsatile cardiac flow conditions. Velocity vectors, streamlines, pressure, and wall shear stress (WSS) and its variance distributions were quantitatively visualized. Results: The maximum pressure andWSS from the time-averaged distribution on the inside saccular surface of the original case are 415.38 and 17.61 Pa. In contrast, the bi-lobed shape gives rise to higher peak values of pressure (461.00 Pa) andWSS (33.20 Pa) on the saccular dome. Conversely, the evenly enlarged aneurysm actually results in a slightly lower peak pressure (399.58 Pa) and drastically decreasedWSS (9.81 Pa). Conclusions:The current study indicates that the size of the aneurysm should not be the only determining factor for the rupture risk consideration, the irregularity of the aneurysm shape and the corresponding aberrant hemodynamics might be a more important factor to consider for risk assessment.

  3. Subtracted vortex centers path line method with cinematic angiography for measurement of flow speed in cerebral aneurysms

    OpenAIRE

    Ohta, M.; Fujimura, N; Augsburger, L.; Barath, K; Yilmaz, H; Abdo, G.; Lovblad, K.O.; Rüfenacht, D.A.

    2008-01-01

    BACKGROUND AND PURPOSE: The assessment of blood flow speed by imaging modalities is of increasing importance for endovascular treatment, such as stent implantation, of cerebral aneurysms. The subtracted vortex centers path line method (SVC method) utilizes image post-processing for determining flow quantitatively. In current practice, intra-aneurysmal flow in an in vitro model is visualized by laser sheet translumination and digitally recorded. In this study, we applied this method to cinemat...

  4. Is there any association between facial type and mandibular dental arch form in subjects with normal occlusion?

    Directory of Open Access Journals (Sweden)

    Luiz Renato Paranhos

    2014-03-01

    The aim of this study was investigate the association between the mandibular arch morphology and the facial type of Brazilian Caucasians with natural normal occlusion. For this, we used a sample comprised of lateral radiographs and respective dental casts of 51 individuals (21 male and 30 female, presenting at least 4 of the 6 Andrews’ keys to normal occlusion without previous orthodontic treatment. Angle’s first molar relationship was considered indispensable for the sample. The facial type was defined by two cephalometric measurements (SN.SGn and SN.GoGn. After scanning the models (3D and radiographs, the images were evaluated by 12 orthodontists. A modified Kappa test evaluated the agreement between examiners to classify the morphology of the dental arch. The chi-square test was used to verify the association between the facial type (dolichofacial, mesofacial, or brachyfacial and the dental arch morphology (square, oval, or tapered, using significance level of 5%. Casual and systematic errors (p > 0.05 showed no significant results and the Kappa test showed significant agreement among examiners for the dental arch form (0.55 with a p < 0.001, considered as ‘moderate’. The chi-square test indicated no significant association. The null hypothesis was accepted, as the facial type was not associated with dental arch morphology in individuals with normal occlusion.

  5. The assessment of crowding without the need to record arch perimeter. Part I: Arches with acceptable alignment.

    Science.gov (United States)

    Battagel, J M

    1996-05-01

    A simplified, mathematically determined technique for calculating arch perimeter (the overlap method) is described and its validity in determining an accurate assessment of crowding is tested. Indices, expressed in millimetres of crowding or spacing, were computed for both the whole arch and the labial segment alone. Study casts of 36 individuals with clinically acceptable lower arches were used to validate the method. The degree of crowding or spacing calculated was compared with a "clinical' assessment of each arch, in which the irregularity was measured directly using a steel ruler. Various calculation schemes were tested. Depending on exactly how the overlap was determined, the results varied slightly. Although the arches showed acceptable alignment, it was preferable to include a strategy for normalizing the positions of any rotated teeth before the overlaps were calculated. Repositioning any bucco-lingually displaced teeth into the line of the arch, however, was not useful. For the complete arch good agreement with the clinical assessment was reached on 31 occasions and for the labial segment, all but one appraisals were within 0.5 mm of each other. In the remaining instances (five complete arches and one labial segment), the degree of crowding or spacing was between 0.5 and 1 mm of the clinical assessment. Considering that clinical measurement of minor degrees of crowding and spacing cannot be precise, these results were considered acceptable. The method was easy to use, relying only on the recording of mesio-distal tooth widths and was acceptably reproducible. The technique would therefore appear to provide a valid yet simple research tool with which to record the degree of crowding. Its ability to cope with irregular and crowded arches will be the subject of a subsequent review.

  6. Infected abdominal aortic aneurysm due to Morganella morganii: CT findings.

    Science.gov (United States)

    Kwon, Oh Young; Lee, Jong Seok; Choi, Han Sung; Hong, Hoon Pyo; Ko, Young Gwan

    2011-02-01

    An infected aortic aneurysm, or mycotic aneurysm, is a rare arterial dilatation due to destruction of the infected vessel wall. Common pathogens resulting in an infected aortic aneurysm are Salmonella and Clostridium species, as well as Staphylococcus aureus; Morganella morganii, on the other hand, is very rare. An infected abdominal aortic aneurysm has tendencies to grow rapidly and to rupture. The mortality rate is high in patients undergoing emergent surgical intervention. We report the case of a 65-year-old man who presented with an infected abdominal aortic aneurysm caused by M. morganii. A high index of suspicion and imaging tests are necessary in order to diagnose an infected aortic aneurysm.

  7. Infectious or Noninfectious? Ruptured, Thrombosed Inflammatory Aortic Aneurysm with Spondylolysis

    Energy Technology Data Exchange (ETDEWEB)

    Stefanczyk, Ludomir; Elgalal, Marcin, E-mail: telgalal@yahoo.co.uk [Medical University of Lodz, Department of Radiology and Diagnostic Imaging (Poland); Papiewski, Andrzej [Medical University of Lodz, Department of Gastroenterological Surgery (Poland); Szubert, Wojciech [Medical University of Lodz, Department of Radiology and Diagnostic Imaging (Poland); Szopinski, Piotr [Institute of Hematology and Transfusion Medicine, Clinic of Vascular Surgery (Poland)

    2013-06-15

    Osteolysis of vertebrae due to inflammatory aortic aneurysm is rarely observed. However, it is estimated that up to 10 % of infectious aneurysms coexist with bone tissue destruction, most commonly the vertebrae. Inflammatory aneurysms with no identified infection factor, along with infiltration of adjacent muscle and in particular extensive destruction of bone tissue have rarely been described in the literature. A case of inflammatory aneurysm with posterior wall rupture and inflammatory infiltration of the iliopsoas muscle and spine, together with extensive vertebral body destruction, is presented. The aneurysm was successfully treated with endovascular aneurysm repair EVAR.

  8. Aneurysm of the aberrant right subclavian artery – a case report

    International Nuclear Information System (INIS)

    The right subclavian artery, originating not from the brachiocephalic trunk but directly from the aortic arch, is a rare anatomical abnormality. ‘Arteria lusoria’ is the accepted name of the retroesophageal right subclavian artery. Such a vessel location, between the vertebral column and the esophagus, determines its course to the right. This defect may be asymptomatic, found during autopsy or coincidentally during diagnostic procedures. However, it may also be symptomatic. The course of this major blood vessel in the limited anatomical space may cause symptoms of mediastinal organ compression. The aim of this paper was to present two cases of abnormal anatomical course of the right subclavian artery and its aneurismal dilation. In this study, CT scans of the saccular aneurysm of the retroesophageal right subclavian artery were used: of a male patient diagnosed at Euromedic Diagnostics in Olsztyn and of a female patient, from the resources of the Radiological Dept. at MSWiA Hospital in Olsztyn An 85-year-old female was admitted to Hospital ER for congestive heart failure decompensation. Her chest X-ray revealed a round mass in the upper right mediastinum. Chest CT confirmed the presence of a saccular aneurysm of the lusory artery, 6.5 cm in diameter, partially filled with thrombotic material. The patient died in hospital from myocardial infarction that was not related to the aneurysm. A 61-year-old male patient had a chest X-ray which showed a round opacity on the apex of the right lung. The diagnostic process comprised also chest computed tomography. The examination showed an anomalous origin of the right subclavian artery, with aneurysmal dilation and compression of the oesophagus and of the trachea. An intraluminal thrombus was found. The patient remained under observation till the next CT examination, 6 months later. The presented rare cases of arteria lusoria aneurysm are not only casuistic reports. They also show the value of modern MDCT diagnostics

  9. A meta-analysis of aneurysm formation in laser assisted vascular anastomosis (LAVA)

    Science.gov (United States)

    Chen, Chen; Peng, Fei; Xu, Dahai; Cheng, Qinghua

    2009-08-01

    Laser assisted vascular anastomosis (LAVA) is looked as a particularly promising non-suture method in future. However, aneurysm formation is one of the main reasons delay the clinical application of LAVA. Some scientists investigated the incidence of aneurysms in animal model. To systematically analyze the literature on reported incidence of aneurysm formation in LAVA therapy, we performed a meta-analysis comparing LAVA with conventional suture anastomosis (CSA) in animal model. Data were systematically retrieved and selected from PUBMED. In total, 23 studies were retrieved. 18 studies were excluded, and 5 studies involving 647 animals were included. Analysis suggested no statistically significant difference between LAVA and CSA (OR 1.24, 95%CI 0.66-2.32, P=0.51). Result of meta analysis shows that the technology of LAVA is very close to clinical application.

  10. Microcatheter looping to facilitate aneurysm selection in coil embolization of paraclinoid aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Dae; Rhim, Jong Kook; Park, Jeong Jin; Jeon, Jin Sue; Yoo, Roh Eul; Kang, Hyun Seung; Kim, Jeong Eun; Cho, Won Sang; Han, Moon Hee [Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2015-08-15

    Described herein is a microcatheter looping technique to facilitate aneurysm selection in paraclinoid aneurysms, which remains to be technically challenging due to the inherent complexity of regional anatomy. This retrospective study was approved by our Institutional Review Board, and informed consent was waived. Microcatheter looping method was employed in 59 patients with paraclinoid aneurysms between January 2012 and December 2013. In the described technique, construction of a microcatheter loop, which is steam-shaped or pre-shaped, based on the direction of aneurysms, is mandatory. The looped tip of microcatheter was advanced into distal internal carotid artery and positioned atop the target aneurysm. By steering the loop (via inner microguidewire) into the dome of aneurysm and easing tension on the microcatheter, the aneurysm was selected. Clinical and morphologic outcomes were assessed with emphasis on technical aspects of the treatment. Through this looping technique, a total of 59 paraclinoid aneurysms were successfully treated. After aneurysm selection as described, single microcatheter technique (n = 25) was most commonly used to facilitate coiling, followed by balloon protection (n = 21), stent protection (n = 7), multiple microcatheters (n = 3), and stent/balloon combination (n = 3). Satisfactory aneurysmal occlusion was achieved through coil embolization in 44 lesions (74.6%). During follow-up of 53 patients (mean interval, 10.9 ± 5.9 months), only one instance (1.9%) of major recanalization was observed. There were no complications related to microcatheter looping. This microcatheter looping method facilitates safe and effective positioning of microcatheter into domes of paraclinoid aneurysms during coil embolization when other traditional microcatheter selection methods otherwise fail.

  11. NeuroArch: A Graph dB for Querying and Executing Fruit Fly Brain Circuits

    OpenAIRE

    Givon, Lev E.; Lazar, Aurel A; Ukani, Nikul H

    2015-01-01

    NeuroArch is a database for codifying knowledge about fruit fly brain circuits. It is designed with two user communities in mind: (i) neurobiologists interested in querying the database to address questions regarding neu- roanatomy, neural circuits, neurons, synapses, neurotransmitters, and gene expression, and (ii) computational neuroscientists interested in the instantiation of models of neural circuits and architectures, their program execution, and validation of hypotheses regarding brain...

  12. Comparison of Retentive Force in Four Attachment Systems in Implant- Supported Overdenture of the Lower Arch

    OpenAIRE

    Ahmadzadeh A; Fereidoonpoor N.

    2012-01-01

    tement of Problem: Along with the rapid population growth in recent decades, there has been an increase in the number of edentulous patients who have complications with conventional denture. This entails the use of dentures, such as implant overdenture, which are more efficacious. Purpose: The purpose of this study is to compare four types of different attachm-ent systems; two prefabricated and two castable attachments. Materials and Method: A model of lower edentulous arch was constructed ...

  13. Accuracy of complete-arch dental impressions: a new method of measuring trueness and precision

    OpenAIRE

    Ender, Andreas; Mehl, Albert

    2013-01-01

    STATEMENT OF PROBLEM: A new approach to both 3-dimensional (3D) trueness and precision is necessary to assess the accuracy of intraoral digital impressions and compare them to conventionally acquired impressions. PURPOSE: The purpose of this in vitro study was to evaluate whether a new reference scanner is capable of measuring conventional and digital intraoral complete-arch impressions for 3D accuracy. MATERIAL AND METHODS: A steel reference dentate model was fabricated and measured with a...

  14. Aneurysm of the vein of Galen

    International Nuclear Information System (INIS)

    We report a case of a vein of Galen aneurysm in a neonate in which MR imaging provided essentially all pertinent diagnostic information prior to surgery. MR findings correlated well with selective cerebral angiography. (orig./MG)

  15. Dissecting aortic aneurysm in maintenance hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Ounissi M

    2009-01-01

    Full Text Available The dissecting aortic aneurysm (DAA is a rare pathology that may result in fatal outcome. We report follow up of three cases of DAA patients undergoing maintenance hemo-dialysis who were managed conservatively.

  16. MR angiography after coiling of intracranial aneurysms

    NARCIS (Netherlands)

    Schaafsma, J.D.

    2012-01-01

    Introduction Endovascular occlusion with detachable coils has become an alternative treatment to neurosurgical clipping of intracranial aneurysms over the last two decades. Its minimal invasiveness is the most important advantage of this treatment compared to clipping. The disadvantage of occlusion

  17. A fibromatosis case mimicking abdominal aorta aneurysm.

    Science.gov (United States)

    Tasdemir, Arzu; Kahraman, Cemal; Tasdemir, Kutay; Mavili, Ertugrul

    2013-01-01

    Retroperitoneal fibrosis is a rare fibrosing reactive process that may be confused with mesenteric fibromatosis. Abdominal aorta aneurysm is rare too and mostly develops secondary to Behcet's disease, trauma, and infection or connective tissue diseases. Incidence of aneurysms occurring as a result of atherosclerotic changes increases in postmenopausal period. Diagnosis can be established with arteriography, tomography, or magnetic resonance imaging associated with clinical findings. Tumors and cysts should be considered in differential diagnosis. Abdominal ultrasound and contrast-enhanced computerized tomography revealed an infrarenal abdominal aorta aneurysm in a 41-year-old woman, but, on surgery, retroperitoneal fibrosis surrounding the aorta was detected. We present this interesting case because retroperitoneal fibrosis encircling the abdominal aorta can mimic abdominal aorta aneurysm radiologically.

  18. Arch development with trans-force lingual appliances.

    Science.gov (United States)

    Clark, William J

    2005-01-01

    Trans-Force lingual appliances are designed to correct arch form in patients with contracted dental arches. Interceptive treatment with this new series of pre-activated lingual appliances offers new possibilities for arch development, in combination with fixed appliances. Palatal and lingual appliances insert in horizontal lingual sheaths in molar bands. No activation is required after the appliance is fitted, and this principle is extended to a series of appliances for sagittal and transverse arch development. Both sagittal and transverse appliances have additional components to achieve 3-way expansion where this is indicated. The invisible lingual appliances may be used in correction of all classes of malocclusion at any stage of development, from mixed dentition through permanent dentition, and this approach has wide indications in adult treatment. PMID:15794037

  19. Endovascular repair of aortic aneurysm: Preliminary results

    Directory of Open Access Journals (Sweden)

    Davidović Lazar

    2009-01-01

    Full Text Available Introduction. Endovascular aneurysm repair (EVAR has been introduced into clinical practice at the beginning of the 90's of the last century. Because of economic, political and social problems during the last 25 years, the introduction of this procedure in Serbia was not possible. Objective. The aim of this study was to present preliminary experiences and results of the Clinic for Vascular Surgery of the Serbian Clinical Centre in Belgrade in endovascular treatment of thoracic and abdominal aortic aneurysms. Methods. The procedure was performed in 33 patients (3 female and 30 male, aged from 42 to 83 years. Ten patients had a descending thoracic aorta aneurysm (three atherosclerotic, four traumatic - three chronic and one acute as a part of polytrauma, one dissected, two penetrated atherosclerotic ulcers, while 23 patients had the abdominal aortic aneurysm, one ruptured and two isolated iliac artery aneurysms. The indications for EVAR were isthmic aneurismal localisation, aged over 80 years and associated comorbidity (cardiac, pulmonary and cerebrovasular diseases, previous thoracotomy or multiple laparotomies associated with abdominal infection, idiopatic thrombocitopaenia. All of these patients had three or more risk factors. The diagnosis was established using duplex ultrasonography, angiography and MSCT. In the case of thoracic aneurysm, a Medtronic-Valiant® endovascular stent graft was implanted, while for the abdominal aortic aneurysm Medtronic-Talent® endovascular stent grafts with delivery systems were used. In three patients, following EVAR a surgical repair of the femoral artery aneurysm was performed, and in another three patients femoro-femoral cross over bypass followed implantation of aortouniiliac stent graft. Results. During procedure and follow-up period (mean 1.6 years, there were: one death, one conversion, one endoleak type 1, six patients with endoleak type 2 that disappeared during the follow-up period, one early graft

  20. CT Virtual angioscopy of aortic arch%CT仿真血管内镜观察主动脉弓

    Institute of Scientific and Technical Information of China (English)

    李新平; 陈伟; 朱智明

    2011-01-01

    [ Objective ] To explore the clinical value of CT virtual angioscopy (CTVA) in the pre- and postpro-cedure evaluation of aortic arch related diseases. [Methods] 37 cases with thoracic disease underwent aortic CT angiography on a dual-source CT scanner. CTVA of aortic arch were performed with Fly-through software in all cas-? Es by using aortic CT angiographic source image data. [Results] 34 of 37 (92%) cases showed successful CTVA images, including aortic dissection (n =12), aneurysm (n =4), pseudoaneurysm (n =3), Takayasu arteritis (n =2),aortic coarctation (n =1), aneurysm combined with aortic dissection (n =1) and 11 patients following surgical or endovascu-lar procedures. CTVA of aortic arch could identify the ostia and its variations of supra-aortic vessels, estimate the localization of abnormalities with respect to supra-aortic vessels and display the stent grafts. [ Conclusions ] CTVA of aortic arch enables non-invasive visualization of the inner contours of the vasculature, and has certain instructive significance in the diagnostic classification, preprocedure planning and postprocedure evaluation for aortic arch related diseases.%目的 探讨CT仿真血管内镜(CTVA)在主动脉弓相关疾病术前和术后评价中的价值.方法 采用双源CT对37例胸主动脉疾病患者行主动脉CT成像检查,并将主动脉CT成像的源图像调至Fly-through软件中,对所有病例行主动脉弓CTVA观察.结果 92%(34/37)的病例获得了满意的CTVA图像,包括主动脉夹层12例、真性动脉瘤4例、假性动脉瘤3例、多发性大动脉炎2例、主动脉缩窄1例、真性动脉瘤合并夹层1例及11例术后随访病例.主动脉弓CTVA能明确弓上分支血管开口位置与变异、判断病变与弓上分支开口的空间关系以及显示支架型血管.结论 主动脉弓CTVA能无创观察血管腔内情况,对主动脉弓相关疾病的诊断分型、术前计划和术后评价具有一定的指导意义.

  1. Multiple Intracranial Aneurysms in HIV Infection.

    Science.gov (United States)

    Dhawan, Sumeet R; Gupta, Anju; Gupta, Vivek; Singhi, Pratibha D

    2016-08-01

    Neurological findings in HIV are common and include cognitive impairment, microcephaly, nonspecific white matter lesions and seizures. Cerebral vasculopathy and stroke are uncommon and may be due to primary HIV vasculopathy or opportunistic infections such as tuberculosis and cryptococcal meningitis. The authors describe a 7-y-old boy who presented with severe headache and was detected to have aneurysmal bleed due to intracranial aneurysm. PMID:27072660

  2. Multiple tuberculous aneurysms of the aorta.

    Science.gov (United States)

    Pierret, Charles; Tourtier, Jean-Pierre; Grand, Bertrand; Boddaert, Guillaume; Laurian, Claude; de Kerangal, Xavier

    2011-06-01

    Tuberculous aneurysms of the aorta are quite rare, but are exceptional when found in multiple locations. We report the case of multiple tuberculous aortic aneurysms of the thoracic and abdominal aorta in a 19-year-old female discovered when she consulted for thrombocytopenic purpura. The treatment for both locations included prolonged antituberculous therapy and surgical resection with cryopreserved aortic allograft patch for the reconstruction.

  3. Direct clipping of large basilar trunk aneurysm.

    Science.gov (United States)

    Kimura, Toshikazu; Nakagawa, Daichi; Kawai, Kensuke

    2015-01-01

    A large basilar trunk aneurysm was incidentally found in a 77-year-old woman in examination for headache. Though it was asymptomatic, high signal intensity was noticed in the brainstem around the aneurysm on FLAIR image of MRI. As she was otherwise healthy, surgical clipping was performed through anterior temporal approach. The video can be found here: http://youtu.be/0soWM8meCW8 . PMID:25554839

  4. Aneurysmal portosystemic venous shunt: a case report.

    Science.gov (United States)

    Bodner, G; Glück, A; Springer, P; König, P; Perkmann, R

    1999-10-01

    A case of an aneurysmal portosystemic venous shunt detected by colour Doppler ultrasound (CDUS) is presented. A young female patient complained of postprandial fatigue and had paroxysmal tachycardia. A direct vascular communication between right portal vein and right hepatic vein was found at CDUS and confirmed by direct portal angiogram. Using detachable coils a complete occlusion of the intrahepatic shunt was obtained. Reports from the literature regarding portovenous aneurysms are reviewed.

  5. Clarifying the anatomy of the fifth arch artery

    Directory of Open Access Journals (Sweden)

    Saurabh Kumar Gupta

    2016-01-01

    Full Text Available The artery allegedly forming in the fifth pharyngeal arch has increasingly been implicated as responsible for various vascular malformations in patients with congenitally malformed hearts. Observations from studies on developing embryos, however, have failed to provide support to substantiate several of these inferences such that the very existence of the fifth arch artery remains debatable. To the best of our knowledge, in only a solitary human embryo has a vascular channel been found that truly resembled the artery of the fifth arch. Despite the meager evidence to support its existence, the fifth arch artery has been invoked to explain the morphogenesis of double-barreled aorta, some unusual forms of aortopulmonary communications, and abnormalities of the brachiocephalic arteries. In most of these instances, the interpretations have proved fallible when examined in the light of existing knowledge of cardiac development. In our opinion, there are more plausible alternative explanations for the majority of these descriptions. Double-barreled aorta is more likely to result from retention of the recently identified dorsal collateral channels while abnormalities of brachiocephalic arteries are better explained on the basis of extensive remodeling of aortic arches during fetal development. Some examples of aortopulmonary communications, nonetheless, may well represent persistence of the developing artery of the fifth pharyngeal arch. We here present one such case - a patient with tetralogy of Fallot and pulmonary atresia, in whom the fifth arch artery provided a necessary communication between the ascending aorta and the pulmonary arteries. In this light, we discuss the features we consider to be essential before attaching the tag of "fifth arch artery" to a candidate vascular channel.

  6. A comparison of four methods of predicting arch length.

    Science.gov (United States)

    Gardner, R B

    1979-04-01

    1. Four arch length prediction equations (Nance, Johnston-Tanaka, Moyers, and Hixon-Oldfather) were compared by examining pretreatment casts, pretreatment intraoral radiographs, and posttreatment casts of forty-one patients of mixed-dentition age. 2. A comparison of correlation coefficients and slopes of the predicted arch length versus the actual arch lengths revealed that the Hixon-Oldfather method conformed closest to the ideal. 3. No combination of the four methods produced a more accurate equation than the single most accurate method. 4. Neither the sex of the patient nor the type of occlusion affected the prediction accuracy of any of the four equations. 5. All methods tend to overpredict the arch length size by 1 to 3 mm., with the exception of the Hixon-Oldfather equation, which underpredicted by approximately 0.5 mm. 6. An analysis of the intrainvestigator error showed a very low standard error of estimate for individual tooth measurements and for the prediction values. 7. A variance analysis showed that most of the variation was due to arch length (85%), a slight amount was due to the prediction method (8%), and 6% of the variation was due to the rater. 8. A low correlation was found between space available versus actual discrepancy and space available versus actual arch length. 9. High correlation coefficients were found for the predicted arch lengths when compared with the actual arch lengths. As expected, the correlation coefficients for the predicted widths of only the canines and premolars compared with the actual widths were not quite as high. PMID:285614

  7. Comparison of arch forms between Turkish and North American

    OpenAIRE

    Ahmet A. Celebi; Hakan Keklik; Enes Tan; Ucar, Faruk I.

    2016-01-01

    ABSTRACT Objective: The aim of this study was to clarify the morphological differences in the mandibular arches of Turkish and North American white subjects. Methods: The sample included 132 Turkish (34 Class I, 58 Class II, and 40 Class III) and 160 North American (60 Class I, 50 Class II, and 50 Class III) subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of patients' mandibular dental arches. Clinical bracket points were calculated for ...

  8. Comparison of arch forms between Turkish and North American

    Directory of Open Access Journals (Sweden)

    Ahmet A. Celebi

    2016-04-01

    Full Text Available ABSTRACT Objective: The aim of this study was to clarify the morphological differences in the mandibular arches of Turkish and North American white subjects. Methods: The sample included 132 Turkish (34 Class I, 58 Class II, and 40 Class III and 160 North American (60 Class I, 50 Class II, and 50 Class III subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of patients' mandibular dental arches. Clinical bracket points were calculated for each tooth based on mandibular tooth thickness data. Four linear and two proportional measurements were taken. The subjects were grouped according to arch form types (tapered, ovoid and square in order to have frequency distribution compared between ethnic groups in each Angle classification. Results: The Turkish group showed significantly lower molar depth and more significant molar width-depth (W/D ratio in all three Angle classifications. On the other hand, the Turkish group also showed a significantly larger intercanine width in Class III malocclusion and intermolar width in Class II malocclusion. The most frequent arch forms seen were the ovoid arch form in the Turkish group and the tapered form in the white group. Conclusions: Our results demonstrate that when treating Turkish patients, one should expect to use preformed ovoid arch form orthodontic wires in a significant percentage of patients.

  9. Developmental feature of the lumbosacral vertebral arch in childhood

    International Nuclear Information System (INIS)

    We investigated a developmental feature of the lumbosacral vertebral arch in childhood that has rarely been reported previously. Sixty-seven patients underwent functional posterior rhizotomy from September 2000 to June 2006 at National Center for Child Health and Development. Sixty of these patients, who had no deformity in their lumbosacral spine, were included in this study and their Computed Tomography (CT) images were analyzed retrospectively. There were 36 boys and 24 girls, aged from 2-12 years. The rate and mean number of non-union vertebral arches between L1 and S3 were 78.3% (95% CI, 65.8-87.9%) and 1.7 (standard deviation (SD), 1.3). The non-union arch was most frequently found at the S1 level, and was more significantly observed in the younger age group (2-5 years of age). The S4 and S5 arches, which often remained open as the sacral hiatus, were constantly open in childhood. This study demonstrates that the vertebral arches of the lumbosacral spine in normal development are often not fused during childhood. It is important to differentiate normal non-union arches from pathological spina bifida. (author)

  10. Intracranial aneurysms in an African country

    Directory of Open Access Journals (Sweden)

    Ogeng'o Julius

    2009-12-01

    Full Text Available Background : Characteristics of intracranial aneurysms display ethnic variations. Data on this disease from the African continent is scarce and often conflicting. Aim : To describe site, age and gender distribution of intracranial aneurysms among Kenyans. Study Design and Setting : Retrospective study at Kenyatta National Hospital, Kenya. Materials and Methods: All records of black African patients with a diagnosis of intracranial aneurysms seen at Kenyatta National Hospital, the largest referral hospital in the Eastern and Central African region, over the period from January 1998 to December 2007 were examined for site, age and gender distribution. The data gathered were coded, analyzed with SPSS 11.50. Results : Fifty-six cases of intracranial aneurysms were analyzed. The posterior communicating artery was the most affected (35.7%, followed by the anterior communicating artery (26.8%, while the posterior cerebral artery was the least affected (2%. Multiple aneurysms were present in 2%. The mean age at presentation was 50.9 years (range 21-80 years and the gender distribution was equal. Conclusions : Intracranial aneurysms among Kenyans occur most commonly on the posterior communicating artery, in young individuals, and without gender bias. The distribution differs from that described in the literature and this requires search for risk factors.

  11. Symptomatic calcified splenic artery aneurysm: Case report

    Directory of Open Access Journals (Sweden)

    Čolović Radoje

    2010-01-01

    Full Text Available Introduction. Although the third most common aneurysm within the abdomen, after aneurysms of the aorta and iliac arteries, splenic artery aneurysms are rare, but not exceptionally. Owing to new imaging techniques, they have been discovered with increasing frequency. Case Outline. Authors present a 47-year-old woman, multipara, who presented with left upper abdominal pain in whom X-ray showed a calcified ring in the area of distal pancreas. Selective angiography confirmed a splenic artery aneurysm of its proximal part. During an open surgery the aneurysm was excised (aneurismectomy without immediate, early or late complications. The patient became symptom-free. Conclusion. In patients, particularly women, the multiparas who present with epigastric or left upper abdominal pain of unknown aetiology, splenic artery aneurysm has to be taken into account. Further diagnostic procedures such as plain X-ray and selective angiography in suspected cases should be performed. Surgery or other treatment modalities are to be seriously considered in all patients, particularly in those with increased risk of rupture.

  12. Endovascular therapeutic strategies in ruptured intracranial aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Machi, Paolo, E-mail: paolo.machi@gmail.com [CHRU Montpellier, Service de Neurorradiologie, Hopital Gui de Chauliac, 80 Avenue Augustin Fliche, 34295 Montpellier Cedex 5 (France); Lobotesis, Kyriakos, E-mail: kyriakos@lobotesis.co.uk [CHRU Montpellier, Service de Neurorradiologie, Hopital Gui de Chauliac, 80 Avenue Augustin Fliche, 34295 Montpellier Cedex 5 (France); Vendrell, Jean Francoise, E-mail: jfvendrell@yahoo.fr [CHRU Montpellier, Service de Neurorradiologie, Hopital Gui de Chauliac, 80 Avenue Augustin Fliche, 34295 Montpellier Cedex 5 (France); Riquelme, Carlos, E-mail: riquelme.carlos@neuf.fr [CHRU Montpellier, Service de Neurorradiologie, Hopital Gui de Chauliac, 80 Avenue Augustin Fliche, 34295 Montpellier Cedex 5 (France); Eker, Omer, E-mail: eker_omer@yahoo.fr [CHRU Montpellier, Service de Neurorradiologie, Hopital Gui de Chauliac, 80 Avenue Augustin Fliche, 34295 Montpellier Cedex 5 (France); Costalat, Vincent, E-mail: vincentcost@hotmail.com [CHRU Montpellier, Service de Neurorradiologie, Hopital Gui de Chauliac, 80 Avenue Augustin Fliche, 34295 Montpellier Cedex 5 (France); Bonafe, Alain, E-mail: bonafeh@aol.com [CHRU Montpellier, Service de Neurorradiologie, Hopital Gui de Chauliac, 80 Avenue Augustin Fliche, 34295 Montpellier Cedex 5 (France)

    2013-10-01

    The aim of the present study was to evaluate endovascular techniques used currently which were not available at the time of ISAT inclusion period, such as balloon remodelling and flow-divertion, in order to assess whether these new technologies have improved the endovascular approach outcomes. We present a review of articles, published in major journals, with the aim to evaluate the efficacy and the safety of coiling with balloon remodelling for the treatment of ruptured aneurysms in comparison to coiling performed without such coadjutant techniques. Furthermore, we reviewed publications reporting on the treatment of ruptured aneurysms in the acute phase with the one of the most recent technologies available nowadays: the flow diverting stent. Looking at the recent literature the results regarding ruptured aneurysms treated with balloon assisted coiling (BAC) have shown an improvement in terms of anatomical results and morbi-mortality rates. Case series of ruptured middle cerebral artery (MCA) aneurysms treated by EVT report results similar to those obtained by surgical clipping. Several articles recently report encouraging results in treating ruptured dissecting and blister aneurysms with flow diverters. Questions regarding the best treatment available for ruptured aneurysms are yet to be answered. Hence there is a need for a subsequent trial aiming to answer these unresolved issues.

  13. Bronchial Artery Aneurysm Embolization with NBCA

    International Nuclear Information System (INIS)

    We present a case of asymptomatic bronchial artery aneurysm that formed a fistula with part of the pulmonary artery (there was no definite fistula with the pulmonary vein). We were able to catheterize the feeding vessel but could not reach the aneurysm. We therefore injected a mixture of N-butyl-2-cyanoacrylate (NBCA; Histoacryl, B. Braun, Melsungen, Germany) and iodized oil (Lipiodol; Guerbet, Aulnay-sous-Bois, France) from the feeding vessel. The fistula, aneurysm, and feeding vessel were almost totally occluded. After embolization, the patient coughed a little; there were no other definite side effects or complications. One and 3 months later, on chest CT, the aneurysm was almost completely occupied with hyperattenuating NBCA-Lipiodol embolization. NBCA is a liquid embolization material whose time to coagulation after injection can be controlled by diluting it with Lipiodol. It is therefore possible to embolize an aneurysm, feeding vessels, and efferent vessels (in our case, it was a fistula) by using an NBCA-Lipiodol mixture of an appropriate concentration, regardless of whether the catheter can reach the aneurysm or not

  14. Maximal aneurysm diameter follow-up is inadequate after endovascular abdominal aortic aneurysm repair

    NARCIS (Netherlands)

    Wever, JJ; Blankensteijn, JD; Mali, WPTM; Eikelboom, BC

    2000-01-01

    Background: follow-up after endovascular abdominal aortic aneurysm repair (EAR) generally consists of serial diameter measurements. A size change after EAR, however, is the consequence of alterations of the excluded aneurysm sac volume. Objective: to assess the agreement between diameter measurement

  15. Endovascular Aneurysm Sealing for Juxtarenal Aneurysm Using the Nellix Device and Chimney Covered Stents

    NARCIS (Netherlands)

    Dijkstra, Martijn L.; Lardenoye, Jan Willem; van Oostayen, Jacques A.; Zeebregts, Clark J.; Reijnen, Michel M. P. J.

    2014-01-01

    Purpose: To show the feasibility of the Nellix device in conjunction with a chimney technique for treating juxtarenal aneurysms in two patients who were deemed unsuitable for fenestrated endovascular aneurysm repair or open surgery. Case Reports: Two men aged 83 and 81 years were referred with a jux

  16. Aneurysmal wall enhancement and perianeurysmal edema after endovascular treatment of unruptured cerebral aneurysms.

    LENUS (Irish Health Repository)

    Su, I-Chang

    2014-06-01

    Perianeurysmal edema and aneurysm wall enhancement are previously described phenomenon after coil embolization attributed to inflammatory reaction. We aimed to demonstrate the prevalence and natural course of these phenomena in unruptured aneurysms after endovascular treatment and to identify factors that contributed to their development.

  17. An unusual case of bilateral coronary artery aneurysms and aortic aneurysms complicated by stenotic lesions

    Energy Technology Data Exchange (ETDEWEB)

    Nakamizo, Reiichirou; Toda, Genji; Koide, Yuji; Kawahara, Fumitaka; Seto, Shinji; Yano, Katsusuke [Nagasaki Univ. (Japan). Graduate School of Biomedical Sciences

    2003-03-01

    A 71-year-old Japanese woman presented with a chief complaint of throbbing sensations in the abdomen. When she was 16 years old, she was exposed to atomic radiation since she was 1.2 km away from the drop zone of the Nagasaki atomic bomb. Abdominal CT performed at the age of 61 revealed the presence of localized calcification below the renal artery, together with abdominal aortic aneurysms measuring 4.9 cm in maximum diameter. Since the abdominal aortic aneurysms enlarged in May 2000, the patient was admitted to our department for further examinations and treatment on July 7. Although the patient did not complain of thoracic symptoms, cardiac catheterization revealed the presence of multiple coronary artery aneurysms and severe stenosis in the main trunk of the left coronary artery and proximal regions of the right coronary artery, together with a complicated collateral circulation course. Coronary artery aneurysms were localized similar to the abdominal aortic aneurysms, and were complicated by severe calcification and obstructive lesions. Coronary arterial bypass grafting was performed after the severity of the coronary artery aneurysms was morphologically evaluated. The course of the abdominal aortic aneurysms was followed without surgical treatment. Although the etiology of the aneurysm formation in this patient was investigated, it remained unclear. (author)

  18. Potential value of aneurysm sac volume measurements in addition to diameter measurements after endovascular aneurysm repair.

    NARCIS (Netherlands)

    Keulen, J.W. van; Prehn, J. van; Prokop, M.; Moll, F.L.; Herwaarden, J.A. van

    2009-01-01

    PURPOSE:To investigate the value of aneurysm sac volume measurement in addition to diameter measurements based on computed tomographic angiography (CTA) after endovascular aneurysm repair (EVAR). METHODS:Interrogation of a vascular database identified 56 patients (51 men; median age 77 years, range

  19. Design and stability analysis of continuous skew tied-arch bridge over Bin Jiang River

    Institute of Scientific and Technical Information of China (English)

    Jiancheng YU; Hao TONG; Wei HUANG

    2008-01-01

    A tied arch bridge without wind bracing was built over the Bin Jiang River, with oblique angle of 20°. Its main design details are described and mechanical performances are analyzed. The stability analytical types are also introduced and the first elastic stability theory is used. A space finite element model has been built to analyze the stability performances in both construction and operation stages for single span or continuous, orthogonal or oblique bridge. The influence of stiffness of the end crossbeam is also analyzed. The result shows that out-plane buckling occur for a rigid tie and similar no matter whether it is single span or continuous and orthogonal or oblique. When there are more and stronger inner crossbeams, the influence of the end crossbeams on arch stability becomes unremarkable.

  20. Microsimulations of Arching, Clogging, and Bursty Exit Phenomena in Crowd Dynamics

    CERN Document Server

    Castro, Francisco Enrique Vicente G

    2015-01-01

    We present in this paper the behavior of an artificial agent who is a member of a crowd. The behavior is based on the social comparison theory, as well as the trajectory mapping towards an agent's goal considering the agent's field of vision. The crowd of artificial agents were able to exhibit arching, clogging, and bursty exit rates. We were also able to observe a new phenomenon we called double arching, which happens towards the end of the simulation, and whose onset is exhibited by a "calm" density graph within the exit passage. The density graph is usually bursty at this area. Because of these exhibited phenomena, we can use these agents with high confidence to perform microsimulation studies for modeling the behavior of humans and objects in very realistic ways.