Radiation dose verification using real tissue phantom in modern radiotherapy techniques

International Nuclear Information System (INIS)

Gurjar, Om Prakash; Mishra, S.P.; Bhandari, Virendra; Pathak, Pankaj; Patel, Prapti; Shrivastav, Garima

2014-01-01

In vitro dosimetric verification prior to patient treatment has a key role in accurate and precision radiotherapy treatment delivery. Most of commercially available dosimetric phantoms have almost homogeneous density throughout their volume, while real interior of patient body has variable and varying densities inside. In this study an attempt has been made to verify the physical dosimetry in actual human body scenario by using goat head as 'head phantom' and goat meat as 'tissue phantom'. The mean percentage variation between planned and measured doses was found to be 2.48 (standard deviation (SD): 0.74), 2.36 (SD: 0.77), 3.62 (SD: 1.05), and 3.31 (SD: 0.78) for three-dimensional conformal radiotherapy (3DCRT) (head phantom), intensity modulated radiotherapy (IMRT; head phantom), 3DCRT (tissue phantom), and IMRT (tissue phantom), respectively. Although percentage variations in case of head phantom were within tolerance limit (< ± 3%), but still it is higher than the results obtained by using commercially available phantoms. And the percentage variations in most of cases of tissue phantom were out of tolerance limit. On the basis of these preliminary results it is logical and rational to develop radiation dosimetry methods based on real human body and also to develop an artificial phantom which should truly represent the interior of human body. (author)

Radiation dose verification using real tissue phantom in modern radiotherapy techniques

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Om Prakash Gurjar

2014-01-01

Full Text Available In vitro dosimetric verification prior to patient treatment has a key role in accurate and precision radiotherapy treatment delivery. Most of commercially available dosimetric phantoms have almost homogeneous density throughout their volume, while real interior of patient body has variable and varying densities inside. In this study an attempt has been made to verify the physical dosimetry in actual human body scenario by using goat head as "head phantom" and goat meat as "tissue phantom". The mean percentage variation between planned and measured doses was found to be 2.48 (standard deviation (SD: 0.74, 2.36 (SD: 0.77, 3.62 (SD: 1.05, and 3.31 (SD: 0.78 for three-dimensional conformal radiotherapy (3DCRT (head phantom, intensity modulated radiotherapy (IMRT; head phantom, 3DCRT (tissue phantom, and IMRT (tissue phantom, respectively. Although percentage variations in case of head phantom were within tolerance limit (< ± 3%, but still it is higher than the results obtained by using commercially available phantoms. And the percentage variations in most of cases of tissue phantom were out of tolerance limit. On the basis of these preliminary results it is logical and rational to develop radiation dosimetry methods based on real human body and also to develop an artificial phantom which should truly represent the interior of human body.

Tratamiento endoluminal de la aorta. Implicaciones en la enfermedad de la aorta torácica

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Miguel Josa García-Tornel

2007-10-01

Full Text Available Durante los últimos años el tratamiento quirúrgico endoluminal de la enfermedad de la aorta (EVAR, endovascular aortic repair se ha convertido en una opción terapéutica en un espectro amplio de pacientes. EVAR es una técnica relativamente fácil, menos agresiva y con aparente menor riesgo con respecto a la cirugía convencional de la aorta. La evidente presión de la industria, a menudo combinada con el lógico interés por su desarrollo por parte de muchos grupos clínicos y el factor moda, tan en boga en nuestros tiempos, han dado a la cirugía endoluminal de la aorta abdominal un desarrollo muy rápido que se está extendiendo en la actualidad a segmentos de la aorta torácica. Aunque los resultados publicados parecen avalar un papel importante de EVAR en algunos grupos específicos de pacientes, su uso en muchos otros grupos es muy controvertido. Su alto coste y los resultados a medio plazo parecen poner en tela de juicio la tendencia a la generalización que existe hoy día. La aplicación a la aorta torácica está asociada con un mayor número de interrogantes. Estudios rigurosos y mejoras técnicas ayudarán, sin duda, a definir mejor su indudable aplicabilidad en el tratamiento de la aorta tanto abdominal como torácica, pero en la actualidad su uso debe estar regulado por un cumplimiento estricto de indicaciones basadas en evidencias clínicas y alejadas de otros intereses, y su práctica debe reducirse a grupos de multiespecialidad preparados en todos los aspectos de la cirugía cardiovascular.

Tracheal replacement by autogenous aorta.

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Anoosh, Farhad; Hodjati, Hossain; Dehghani, Seifollah; Tanideh, Nader; Kumar, Perikala V

2009-06-09

Tracheal defects may occur after trauma or prolonged intubation. Resection of tracheal tumors also poses a major challenge for substitution. In an effort to solve this problem, different techniques have been tried with little success. We report on a new animal model which showed acceptable results with fewer complications. We replaced 5 cm of cervical trachea in 10 dogs with harvested infra-renal aorta and repaired the aortic defect with Dacron graft. Necropsy of the grafted aorta and anastomotic site revealed well healed anastomosis in all animals together with ciliated columnar epithelium coverage of grafted aorta and neovascularization of aortic wall. Aortic graft is preferable to other substitutes because of less antigenicity, less vascularity, and no mucous secretions or peristalsis.

Usefulness of a functional tracheobronchial phantom for interventional procedure

International Nuclear Information System (INIS)

Kim, Tae Hyung; Lim, Cheong Hwan; Kim, Jeong Koo

2003-01-01

To evaluate usefulness of a functional tracheobronchial phantom for interventional procedure. The functional phantom was made as a actual size with human normal anatomy used silicone and a paper clay mold. A tracheobronchial-shape clay mold was placed inside a square box and liquid silicone was poured. After the silicone was formed, the clay was removed. We measured film density and tracheobronchial angle at the human, animal and phantom respectively. The film density of trachea part were 0.76 (± 0.011) in human, 0.97 (± 0.015) in animal, 0.45 (± 0.016) in phantom. The tracheobronchial bifurcation part measured 0.51 (± 0.006) in human, 0.65 (± 0.005) in animal, 0.65 (± 0.008) in phantom. The right bronchus part measured 0.14 (± 0.008) in human, 0.59 (± 0.014) in animal and 0.04 (± 0.007) in phantom. The left bronchus were 0.54 (± 0.004) in human, 0.54 (± 0.008) in animal and 0.08 (± 0.008) in phantom. At the stent part were 0.54 (± 0.004) in human, 0.59 (± 0.011) in animal and 0.04 (± 0.007) in phantom, respectively. The tracheobronchial angle of the left bronchus site were 42.6 (± 2.07).deg. in human, 43.4 (± 2.40).deg. in animal and 35 (± 2.00).deg. in phantom, respectively. The right bronchus site were 32.8 (± 2.77).deg. in human, 34.6 (± 1.94).deg. in animal and 50.2 (± 1.30).deg. in phantom, respectively. The phantom was useful for in-vitro testing of tracheobronchial interventional procedure, since it was easy to reproduce

Symbol phantoms

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Yamaguchi, Hiroshi; Hongo, Syozo; Takeshita, Hiroshi

1990-01-01

We have developed Japanese phantoms in two procedures for computation of organ doses exposed to internal and/or external radiation sources. One method is to make mathematical phantoms on the basis of ORNL mathematical phantoms. Parameters to specify organs of Japanese mathematical phantom are determined by interpolations of the ORNL data, which define the organs of Caucasian males and females of various ages, i.e. new born, 1, 5, 10, 15 years and adult, with survey data for Japanese physiques. Another procedure is to build 'symbol phantoms' for the Japanese public. The concept and its method of the symbol phantom enables us to make a phantom for an individual when we have all of his transversal section images obtained by a medical imaging device like MRI, and thus we may achieve more realistic phantoms for Japanese public than the mathematical phantoms. Both studies are in progress in NIRS. (author)

Tracheal replacement by autogenous aorta

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Anoosh Farhad

2009-06-01

Full Text Available Abstract Background Tracheal defects may occur after trauma or prolonged intubation. Resection of tracheal tumors also poses a major challenge for substitution. In an effort to solve this problem, different techniques have been tried with little success. We report on a new animal model which showed acceptable results with fewer complications. Methods We replaced 5 cm of cervical trachea in 10 dogs with harvested infra-renal aorta and repaired the aortic defect with Dacron graft. Results Necropsy of the grafted aorta and anastomotic site revealed well healed anastomosis in all animals together with ciliated columnar epithelium coverage of grafted aorta and neovascularization of aortic wall. Conclusion Aortic graft is preferable to other substitutes because of less antigenicity, less vascularity, and no mucous secretions or peristalsis

6-Gingerol alleviates exaggerated vasoconstriction in diabetic rat aorta through direct vasodilation and nitric oxide generation

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Ghareib SA

2015-11-01

Full Text Available Salah A Ghareib,1 Hany M El-Bassossy,1,2 Ahmed A Elberry,3,4 Ahmad Azhar,5 Malcolm L Watson,6 Zainy Mohammed Banjar7 1Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia; 2Department of Pharmacology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt; 3Department of Clinical Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia; 4Department of Pharmacology, Faculty of Medicine, Beni Suef University, Beni Suef, Egypt; 5Department of Pediatric Cardiology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia; 6Department of Pharmacy and Pharmacology, University of Bath, Bath, UK; 7Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia Abstract: The aim of the present study is to investigate the effect and potential mechanism of action of 6-gingerol on alterations of vascular reactivity in the isolated aorta from diabetic rats. Male Wistar rats were divided into two experimental groups, control and diabetics. Diabetes was induced by a single intraperitoneal injection of streptozotocin (50 mg kg-1, and the rats were left for 10 weeks to develop vascular complications. The effect of in vitro incubation with 6-gingerol (0.3–3 µM on the vasoconstrictor response of the isolated diabetic aortae to phenylephrine and the vasodilator response to acetylcholine was examined. Effect of 6-gingerol was also examined on aortae incubated with methylglyoxal as an advanced glycation end product (AGE. To investigate the mechanism of action of 6-gingerol, the nitric oxide synthase inhibitor Nω-nitro-L-arginine methyl ester hydrochloride (100 µM, guanylate cyclase inhibitor methylene blue (5 µM, calcium-activated potassium channel blocker tetraethylammonium chloride (10 mM, and cyclooxygenase inhibitor indomethacin (5 µM were added 30 minutes before assessing the direct vasorelaxant effect of 6

The normal distribution of thoracoabdominal aorta small branch artery ostia

International Nuclear Information System (INIS)

Cronin, Paul; Williams, David M.; Vellody, Ranjith; Kelly, Aine Marie; Kazerooni, Ella A.; Carlos, Ruth C.

2011-01-01

The purpose of this study was to determine the normal distribution of aortic branch artery ostia. CT scans of 100 subjects were retrospectively reviewed. The angular distributions of the aorta with respect to the center of the T3 to L4 vertebral bodies, and of branch artery origins with respect to the center of the aorta were measured. At each vertebral body level the distribution of intercostal/lumbar arteries and other branch arteries were calculated. The proximal descending aorta is posteriorly placed becoming a midline structure, at the thoracolumbar junction, and remains anterior to the vertebral bodies within the abdomen. The intercostal and lumbar artery ostia have a distinct distribution. At each vertebral level from T3 caudally, one intercostal artery originates from the posterior wall of the aorta throughout the thoracic aorta, while the other intercostal artery originates from the medial wall of the descending thoracic aorta high in the chest, posteromedially from the mid-thoracic aorta, and from the posterior wall of the aorta low in the chest. Mediastinal branches of the thoracic aorta originate from the medial and anterior wall. Lumbar branches originate only from the posterior wall of the abdominal aorta. Aortic branch artery origins arise with a bimodal distribution and have a characteristic location. Mediastinal branches of the thoracic aorta originate from the medial and anterior wall. Knowing the location of aortic branch artery ostia may help distinguish branch artery pseudoaneurysms from penetrating ulcers.

Fourier transform infrared spectroscopy to quantify collagen and elastin in an in vitro model of extracellular matrix degradation in aorta.

Science.gov (United States)

Cheheltani, Rabee; McGoverin, Cushla M; Rao, Jayashree; Vorp, David A; Kiani, Mohammad F; Pleshko, Nancy

2014-06-21

Extracellular matrix (ECM) is a key component and regulator of many biological tissues including aorta. Several aortic pathologies are associated with significant changes in the composition of the matrix, especially in the content, quality and type of aortic structural proteins, collagen and elastin. The purpose of this study was to develop an infrared spectroscopic methodology that is comparable to biochemical assays to quantify collagen and elastin in aorta. Enzymatically degraded porcine aorta samples were used as a model of ECM degradation in abdominal aortic aneurysm (AAA). After enzymatic treatment, Fourier transform infrared (FTIR) spectra of the aortic tissue were acquired by an infrared fiber optic probe (IFOP) and FTIR imaging spectroscopy (FT-IRIS). Collagen and elastin content were quantified biochemically and partial least squares (PLS) models were developed to predict collagen and elastin content in aorta based on FTIR spectra. PLS models developed from FT-IRIS spectra were able to predict elastin and collagen content of the samples with strong correlations (RMSE of validation = 8.4% and 11.1% of the range respectively), and IFOP spectra were successfully used to predict elastin content (RMSE = 11.3% of the range). The PLS regression coefficients from the FT-IRIS models were used to map collagen and elastin in tissue sections of degraded porcine aortic tissue as well as a human AAA biopsy tissue, creating a similar map of each component compared to histology. These results support further application of FTIR spectroscopic techniques for evaluation of AAA tissues.

Fourier Transform Infrared Spectroscopy to Quantify Collagen and Elastin in an In Vitro Model of Extracellular Matrix Degradation in Aorta

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Cheheltani, Rabee; McGoverin, Cushla M.; Rao, Jayashree; Vorp, David A.; Kiani, Mohammad F.; Pleshko, N.

2014-01-01

Extracellular matrix (ECM) is a key component and regulator of many biological tissues including aorta. Several aortic pathologies are associated with significant changes in the composition of the matrix, especially in the content, quality and type of aortic structural proteins, collagen and elastin. The purpose of this study was to develop an infrared spectroscopic methodology that is comparable to biochemical assays to quantify collagen and elastin in aorta. Enzymatically degraded porcine aorta samples were used as a model of ECM degradation in abdominal aortic aneurysm (AAA). After enzymatic treatment, Fourier transform infrared (FTIR) spectra of the aortic tissue were acquired by an infrared fiber optic probe (IFOP) and FTIR imaging spectroscopy (FT-IRIS). Collagen and elastin content were quantified biochemically and partial least squares (PLS) models were developed to predict collagen and elastin content in aorta based on FTIR spectra. PLS models developed from FT-IRIS spectra were able to predict elastin and collagen content of the samples with strong correlations (RMSE of validation = 8.4% and 11.1% of the range respectively), and IFOP spectra were successfully used to predict elastin content (RMSE = 11.3% of the range). The PLS regression coefficients from the FT-IRIS models were used to map collagen and elastin in tissue sections of degraded porcine aortic tissue as well as a human AAA biopsy tissue, creating a similar map of each component compared to histology. These results support further application of FTIR spectroscopic techniques for evaluation of AAA tissues. PMID:24761431

Conversion of ICRP male reference phantom to polygon-surface phantom

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Yeom, Yeon Soo; Han, Min Cheol; Kim, Chan Hyeong; Jeong, Jong Hwi

2013-10-01

The International Commission on Radiological Protection (ICRP) reference phantoms, developed based on computed tomography images of human bodies, provide much more realism of human anatomy than the previously used MIRD5 (Medical Internal Radiation Dose) mathematical phantoms. It has been, however, realized that the ICRP reference phantoms have some critical limitations showing a considerable amount of holes for the skin and wall organs mainly due to the nature of voxels of which the phantoms are made, especially due to their low voxel resolutions. To address this problem, we are planning to develop the polygon-surface version of ICRP reference phantoms by directly converting the ICRP reference phantoms (voxel phantoms) to polygon-surface phantoms. The objective of this preliminary study is to see if it is indeed possible to construct the high-quality polygon-surface phantoms based on the ICRP reference phantoms maintaining identical organ morphology and also to identify any potential issues, and technologies to address these issues, in advance. For this purpose, in the present study, the ICRP reference male phantom was roughly converted to a polygon-surface phantom. Then, the constructed phantom was implemented in Geant4, Monte Carlo particle transport code, for dose calculations, and the calculated dose values were compared with those of the original ICRP reference phantom to see how much the calculated dose values are sensitive to the accuracy of the conversion process. The results of the present study show that it is certainly possible to convert the ICRP reference phantoms to surface phantoms with enough accuracy. In spite of using relatively less resources (original ICRP reference phantoms, it is believed that the polygon-surface version of ICRP reference phantoms properly developed will not only provide the same or similar dose values (say, difference <5 or 10%) for highly penetrating radiations, but also provide correct dose values for the weakly penetrating

Computational modeling of blood flow in the aorta--insights into eccentric dilatation of the ascending aorta after surgery for coarctation.

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Szopos, Marcela; Poussineau, Nicole; Maday, Yvon; Canniffe, Carla; Celermajer, David S; Bonnet, Damien; Ou, Phalla

2014-10-01

To assess whether combining a computational modeling technique with data from patient magnetic resonance imaging studies can detect different fluid dynamics and vascular biomechanical properties of the ascending and horizontal aorta in patients with angulated "gothic" arch geometry compared with those with normal "Romanesque" arch geometry after aortic coarctation repair. Advanced computational fluid dynamics techniques (coupled Navier-Stokes and elastodynamics equations) were used to predict the fluid-wall interactions in large arteries. We modeled the fluid dynamics and shear stress in the ascending and horizontal aorta in cases of "gothic" arch and normal "Romanesque" aortic arch geometry. A total of 30 patients after aortic coarctation repair prospectively underwent 3-dimensional magnetic resonance imaging angiography of the thoracic aorta. Measurements of the ascending and horizontal aorta were assessed using multiplanar reformatting images. Our computational model demonstrated that wall shear stress is greater in those with an angulated "gothic" aortic arch than in those with a "Romanesque" arch. In particular, wall shear stress affected the anterior and posterior segments of the ascending aorta and the inferior and superior segments of the horizontal aorta (vs the left and right segments). In vivo, a "gothic" arch was associated with dilatation of the ascending and horizontal aorta, which was eccentric rather than concentric (Pgothic" aortic arch after repair of coarctation. This suggests that patients with an angulated "gothic" aortic arch might warrant increased surveillance for aortic complications. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

1,4-Anhydro-4-seleno-d-talitol (SeTal) protects endothelial function in the mouse aorta by scavenging superoxide radicals under conditions of acute oxidative stress

DEFF Research Database (Denmark)

Ng, Hooi Hooi; Leo, Chen Huei; O'Sullivan, Kelly

2017-01-01

and decreased basal nitric oxide (NO) availability. SeTal (1mM) co-treatment prevented high glucose-induced endothelial dysfunction and oxidative stress in the mouse aorta. The presence of a cyclooxygenase inhibitor, indomethacin significantly improved the sensitivity to ACh in high glucose-treated aortae......, but had no effect in SeTal-treated aortae. Our data show that SeTal has potent antioxidant activity in isolated mouse aortae and prevents high glucose-induced endothelial dysfunction by decreasing superoxide levels, increasing basal NO availability and normalising the contribution of vasoconstrictor......Hyperglycaemia increases the generation of reactive oxidants in blood vessels and is a major cause of endothelial dysfunction. A water-soluble selenium-containing sugar (1,4-Anhydro-4-seleno-d-talitol, SeTal) has potent antioxidant activity in vitro and is a promising treatment to accelerate wound...

Conversion of ICRP male reference phantom to polygon-surface phantom

International Nuclear Information System (INIS)

Yeom, Yeon Soo; Han, Min Cheol; Kim, Chan Hyeong; Jeong, Jong Hwi

2013-01-01

The International Commission on Radiological Protection (ICRP) reference phantoms, developed based on computed tomography images of human bodies, provide much more realism of human anatomy than the previously used MIRD5 (Medical Internal Radiation Dose) mathematical phantoms. It has been, however, realized that the ICRP reference phantoms have some critical limitations showing a considerable amount of holes for the skin and wall organs mainly due to the nature of voxels of which the phantoms are made, especially due to their low voxel resolutions. To address this problem, we are planning to develop the polygon-surface version of ICRP reference phantoms by directly converting the ICRP reference phantoms (voxel phantoms) to polygon-surface phantoms. The objective of this preliminary study is to see if it is indeed possible to construct the high-quality polygon-surface phantoms based on the ICRP reference phantoms maintaining identical organ morphology and also to identify any potential issues, and technologies to address these issues, in advance. For this purpose, in the present study, the ICRP reference male phantom was roughly converted to a polygon-surface phantom. Then, the constructed phantom was implemented in Geant4, Monte Carlo particle transport code, for dose calculations, and the calculated dose values were compared with those of the original ICRP reference phantom to see how much the calculated dose values are sensitive to the accuracy of the conversion process. The results of the present study show that it is certainly possible to convert the ICRP reference phantoms to surface phantoms with enough accuracy. In spite of using relatively less resources (<2 man-months), we were able to construct the polygon-surface phantom with the organ masses perfectly matching the ICRP reference values. The analysis of the calculated dose values also implies that the dose values are indeed not very sensitive to the detailed morphology of the organ models in the phantom

A comparative study on patient specific absolute dosimetry using slab phantom, acrylic body phantom and goat head phantom

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Om Prakash Gurjar

2015-01-01

Full Text Available Purpose: To compare the results of patient specific absolute dosimetry using slab phantom, acrylic body phantom and goat head phantom. Methods: Fifteen intensity modulated radiotherapy (IMRT plans already planned on treatment planning system (TPS for head-and-neck cancer patients were exported on all three kinds of phantoms viz. slab phantom, acrylic body phantom and goat head phantom, and dose was calculated using anisotropic analytic algorithm (AAA. All the gantry angles were set to zero in case of slab phantom while set to as it is in actual plan in case of other two phantoms. All the plans were delivered by linear accelerator (LA and dose for each plan was measured by 0.13 cc ion chamber. The percentage (% variations between planned and measured doses were calculated and analyzed. Results: The mean % variations between planned and measured doses of all IMRT quality assurance (QA plans were as 0.65 (Standard deviation (SD: 0.38 with confidence limit (CL 1.39, 1.16 (SD: 0.61 with CL 2.36 and 2.40 (SD: 0.86 with CL 4.09 for slab phantom, acrylic head phantom and goat head phantom respectively. Conclusion: Higher dose variations found in case of real tissue phantom compare to results in case of slab and acrylic body phantoms. The algorithm AAA does not calculate doses in heterogeneous medium as accurate as it calculates in homogeneous medium. Therefore the patient specific absolute dosimetry should be done using heterogeneous phantom mimicking density wise as well as design wise to the actual human body.  

Rapid MR measurements of contrast medium dilution kinetics (gadolinium-DTPA) in a flow phantom

International Nuclear Information System (INIS)

Boeck, J.C.; Sander, B.; Frank, J.; Schoerner, W.

1991-01-01

We studied first-pass MRI-contrast dilution to compute flow and volume of distribution in a realistic flow phantom. Pulsatile flow was provided by a one-chamber artificial heart. Physiological stroke volume, rate, pressure, and flow were adjustable. An elastic tube with dimensions similar to that of the human aorta was imaged at a rate of 2.4 Hz. After contrast injection, an initial increase in signal intensity was followed by a decrease. Signal-intensity-time plots demonstrated slightly skewed curves as expected from dispersion theory. After calibration at different gadolinium-DTPA concentrations, signal intensities were converted into true gadolinium concentrations, and flow was calculated from the concentration-time curves. Flow was varied between 2.5 and 10.0 l/min and a significant correlation was found between the MRI-estimate and true flow. Volume of distribution between injection and detection site was reliably estimated. This study demonstrates rapid 2-D imaging of a paramagnetic contrast bolus in a realistic flow phantom. Reliable estimates of flow and volume are obtained. (orig.) [de

Valsartan ameliorates ageing-induced aorta degeneration via angiotensin II type 1 receptor-mediated ERK activity

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Shan, HaiYan; Zhang, Siyang; Li, Xuelian; yu, Kai; Zhao, Xin; Chen, Xinyue; Jin, Bo; Bai, XiaoJuan

2014-01-01

Angiotensin II (Ang II) plays important roles in ageing-related disorders through its type 1 receptor (AT1R). However, the role and underlying mechanisms of AT1R in ageing-related vascular degeneration are not well understood. In this study, 40 ageing rats were randomly divided into two groups: ageing group which received no treatment (ageing control), and valsartan group which took valsartan (selective AT1R blocker) daily for 6 months. 20 young rats were used as adult control. The aorta structure were analysed by histological staining and electron microscopy. Bcl-2/Bax expression in aorta was analysed by immunohistochemical staining, RT-PCR and Western blotting. The expressions of AT1R, AT2R and mitogen-activated protein kinases (MAPKs) were detected. Significant structural degeneration of aorta in the ageing rats was observed, and the degeneration was remarkably ameliorated by long-term administration of valsartan. With ageing, the expression of AT1R was elevated, the ratio of Bcl-2/Bax was decreased and meanwhile, an important subgroup of MAPKs, extracellular signal-regulated kinase (ERK) activity was elevated. However, these changes in ageing rats could be reversed to some extent by valsartan. In vitro experiments observed consistent results as in vivo study. Furthermore, ERK inhibitor could also acquire partial effects as valsartan without affecting AT1R expression. The results indicated that AT1R involved in the ageing-related degeneration of aorta and AT1R-mediated ERK activity was an important mechanism underlying the process. PMID:24548645

Evaluation of atherosclerotic change of the aorta by enhanced computed tomography

International Nuclear Information System (INIS)

Takasu, Junichiro

1990-01-01

Intimal atherosclerotic changes of the aorta were quantified by enhanced computed tomography (enhanced CT) and were examined in terms of their relation to other atherosclerotic characteristics, including calcification and aortic pulse wave velocity, diameter of the aorta, and arteriosclerotic risk factors. A total of 413 subjects were studied, consisting of normal volunteers and patients with cardiovascular diseases. Enhanced CT revealed the atheromatous intima as a projecting and thickened wall. Thus, the ratio of the intimal atherosclerotic change to the whole round was determined in various aortic sites. The diameter of the aorta decreased in accordance with the location from the ascending aorta to aortic ending. The diameter of the infrarenal abdominal aorta was 1.5 times larger than that of the ascending aorta, irrespective of age. The diameter of each region of the aorta increased with advancing age; in the age group of 70 years or older, it was 1.5 times larger that that in the age group of 40 years or younger. The intimal change was noted in the middle descending thoracic aorta and infrarenal abdominal aorta. It was proportional to an increase in the aortic pulse wave velocity, the diameter of the aorta, and the intimal calcification. Intimal changes of the aorta were increased in cerebrovascular disease, ischemic heart disease, arteriosclerosis obliterans, hypertension and diabetes mellitus. In particular, hypertension accompanied by diabetes mellitus or high cholesterolemia tended to accelerate the intimal change. In conclusion, aortic intimal changes, as detected on enhanced CT, is useful for the noninvasive diagnosis of arteriosclerosis. (N.K.)

Control volume based hydrocephalus research; a phantom study

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Cohen, Benjamin; Voorhees, Abram; Madsen, Joseph; Wei, Timothy

2009-11-01

Hydrocephalus is a complex spectrum of neurophysiological disorders involving perturbation of the intracranial contents; primarily increased intraventricular cerebrospinal fluid (CSF) volume and intracranial pressure are observed. CSF dynamics are highly coupled to the cerebral blood flows and pressures as well as the mechanical properties of the brain. Hydrocephalus, as such, is a very complex biological problem. We propose integral control volume analysis as a method of tracking these important interactions using mass and momentum conservation principles. As a first step in applying this methodology in humans, an in vitro phantom is used as a simplified model of the intracranial space. The phantom's design consists of a rigid container filled with a compressible gel. Within the gel a hollow spherical cavity represents the ventricular system and a cylindrical passage represents the spinal canal. A computer controlled piston pump supplies sinusoidal volume fluctuations into and out of the flow phantom. MRI is used to measure fluid velocity and volume change as functions of time. Independent pressure measurements and momentum flow rate measurements are used to calibrate the MRI data. These data are used as a framework for future work with live patients and normal individuals. Flow and pressure measurements on the flow phantom will be presented through the control volume framework.

Effects of thapsigargin in isolated rat thoracic aorta

DEFF Research Database (Denmark)

Mikkelsen, E O; Thastrup, Ole; Christensen, S B

1988-01-01

The effect of thapsigargin (Tg) was studied in rat thoracic aorta. Tg (10(-8)-10(-5) M) had a dual effect on rat aorta. Thus, Tg induced a concentration dependent increase in basal tone in normal physiological salt solution (PSS), while Tg in potassium (K+) precontracted aortic rings caused a con...... A 23187 had an endothelium dependent relaxant effect on rat aorta different from that of carbachol. The results indicate that Tg in vascular smooth muscle acts by stimulating the transmembranal influx of extracellular calcium....

A tissue phantom for visualization and measurement of ultrasound-induced cavitation damage.

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Maxwell, Adam D; Wang, Tzu-Yin; Yuan, Lingqian; Duryea, Alexander P; Xu, Zhen; Cain, Charles A

2010-12-01

Many ultrasound studies involve the use of tissue-mimicking materials to research phenomena in vitro and predict in vivo bioeffects. We have developed a tissue phantom to study cavitation-induced damage to tissue. The phantom consists of red blood cells suspended in an agarose hydrogel. The acoustic and mechanical properties of the gel phantom were found to be similar to soft tissue properties. The phantom's response to cavitation was evaluated using histotripsy. Histotripsy causes breakdown of tissue structures by the generation of controlled cavitation using short, focused, high-intensity ultrasound pulses. Histotripsy lesions were generated in the phantom and kidney tissue using a spherically focused 1-MHz transducer generating 15 cycle pulses, at a pulse repetition frequency of 100 Hz with a peak negative pressure of 14 MPa. Damage appeared clearly as increased optical transparency of the phantom due to rupture of individual red blood cells. The morphology of lesions generated in the phantom was very similar to that generated in kidney tissue at both macroscopic and cellular levels. Additionally, lesions in the phantom could be visualized as hypoechoic regions on a B-mode ultrasound image, similar to histotripsy lesions in tissue. High-speed imaging of the optically transparent phantom was used to show that damage coincides with the presence of cavitation. These results indicate that the phantom can accurately mimic the response of soft tissue to cavitation and provide a useful tool for studying damage induced by acoustic cavitation. Copyright © 2010 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Effect of coarctation of the aorta and bicuspid aortic valve on flow dynamics and turbulence in the aorta using particle image velocimetry

Science.gov (United States)

Keshavarz-Motamed, Zahra; Garcia, Julio; Gaillard, Emmanuel; Maftoon, Nima; Di Labbio, Giuseppe; Cloutier, Guy; Kadem, Lyes

2014-03-01

Blood flow in the aorta has been of particular interest from both fluid dynamics and physiology perspectives. Coarctation of the aorta (COA) is a congenital heart disease corresponding to a severe narrowing in the aortic arch. Up to 85 % of patients with COA have a pathological aortic valve, leading to a narrowing at the valve level. The aim of the present work was to advance the state of understanding of flow through a COA to investigate how narrowing in the aorta (COA) affects the characteristics of the velocity field and, in particular, turbulence development. For this purpose, particle image velocimetry measurements were conducted at physiological flow and pressure conditions, with three different aorta configurations: (1) normal case: normal aorta + normal aortic valve; (2) isolated COA: COA (with 75 % reduction in aortic cross-sectional area) + normal aortic valve and (3) complex COA: COA (with 75 % reduction in aortic cross-sectional area) + pathological aortic valve. Viscous shear stress (VSS), representing the physical shear stress, Reynolds shear stress (RSS), representing the turbulent shear stress, and turbulent kinetic energy (TKE), representing the intensity of fluctuations in the fluid flow environment, were calculated for all cases. Results show that, compared with a healthy aorta, the instantaneous velocity streamlines and vortices were deeply changed in the presence of the COA. The normal aorta did not display any regions of elevated VSS, RSS and TKE at any moment of the cardiac cycle. The magnitudes of these parameters were elevated for both isolated COA and complex COA, with their maximum values mainly being located inside the eccentric jet downstream of the COA. However, the presence of a pathologic aortic valve, in complex COA, amplifies VSS (e.g., average absolute peak value in the entire aorta for a total flow of 5 L/min: complex COA: = 36 N/m2; isolated COA = 19 N/m2), RSS (e.g., average peak value in the entire aorta for a total flow of 5

Computer tomographic phantom

International Nuclear Information System (INIS)

Lonn, A.H.R.; Jacobsen, D.R.; Zech, D.J.

1988-01-01

A reference phantom for computer tomography employs a flexible member with means for urging the flexible member into contact along the curved surface of the lumbar region of a human patient. In one embodiment, the reference phantom is pre-curved in an arc greater than required. Pressure from the weight of a patient laying upon the reference phantom is effective for straightening out the curvature sufficiently to achieve substantial contact along the lumbar region. The curvature of the reference phantom may be additionally distorted by a resilient pad between the resilient phantom and a table for urging it into contact with the lumbar region. In a second embodiment of the invention, a flexible reference phantom is disposed in a slot in the top of a resilient cushion. The resilient cushion and reference phantom may be enclosed in a flexible container. A partially curved reference phantom in a slot in a resilient cushion is also contemplated. (author)

Dose distribution in organs: patient-specific phantoms versus reference phantoms

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Lacerda, I.V.B., E-mail: isabelle.lacerda@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife (Brazil); Vieira, J.W. [Instituto Federal de Pernambuco (IFPE), Recife (Brazil); Oliveira, M.L.; Lima, F.R.A. [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PB), Recife (Brazil)

2017-07-01

Discrepancies between ICRP phantoms and real patients lead to disparities on patient-dose estimations. This paper aims to compare distribution of dose in organs of male/female specific-phantoms and ICRP reference phantoms. The absorbed dose estimation was performed using the EGSnrc Monte Carlo code and a parallel source algorithm. In this work were used a patient-specific phantom for a man (1.73m/70.3kg) and another for a woman (1.63m/60.3kg) and the male and female ICRP reference phantoms. The comparison of the absorbed dose from each phantom gender was performed using the relative error. The results were expressed in terms of conversion coefficients to brain, lungs, liver and kidneys. The greatest absolute relative error between the organs of the patient-specific phantom and the reference phantom was 22.92% in the liver and 62.84% in the kidneys, respectively for man and woman. There are errors that cannot be disregarded. This paper shows the need for a specific study for each patient or for the population of each country, since there are different body types, which affects the distribution of the organ doses. (author)

Dose distribution in organs: patient-specific phantoms versus reference phantoms

International Nuclear Information System (INIS)

Lacerda, I.V.B.; Vieira, J.W.; Oliveira, M.L.; Lima, F.R.A.

2017-01-01

Discrepancies between ICRP phantoms and real patients lead to disparities on patient-dose estimations. This paper aims to compare distribution of dose in organs of male/female specific-phantoms and ICRP reference phantoms. The absorbed dose estimation was performed using the EGSnrc Monte Carlo code and a parallel source algorithm. In this work were used a patient-specific phantom for a man (1.73m/70.3kg) and another for a woman (1.63m/60.3kg) and the male and female ICRP reference phantoms. The comparison of the absorbed dose from each phantom gender was performed using the relative error. The results were expressed in terms of conversion coefficients to brain, lungs, liver and kidneys. The greatest absolute relative error between the organs of the patient-specific phantom and the reference phantom was 22.92% in the liver and 62.84% in the kidneys, respectively for man and woman. There are errors that cannot be disregarded. This paper shows the need for a specific study for each patient or for the population of each country, since there are different body types, which affects the distribution of the organ doses. (author)

Arma branca retida em aorta abdominal superior

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Fernando Antonio C. Spencer Netto

Full Text Available Abdominal aorta wounds carries a high immediate mortality. Few patients reach hospital care alive. There are no reports on Medline (1969-2002 about aortic wounds of foreign body with retention. A case with upper abdominal aortic wound with an inlaid blade is reported. The retained blade fixed the stomach to the surgical field, difficulting the vascular control, leading to an unconventional approach and allowing extensive contamination. The patient developed multiple organ dysfunction and died at fifth postoperative day. Singularities of an inlaid knife in upper abdominal aorta and changes in traditional approach are discussed. The authors assumed that the inlaid knife decreased the bleeding, allowing the patient arrival to the hospital, but worsened the approach to the aorta wound.

Coarctation of the Aorta

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... the wall of the left ventricle to thicken (hypertrophy). Risk factors Coarctation of the aorta often occurs ... body. Over time, this can cause your heart muscle to thicken and lead to symptoms such as ...

Mechanical Characterization and Material Modeling of Diabetic Aortas in a Rabbit Model.

Science.gov (United States)

Tong, Jianhua; Yang, F; Li, X; Xu, X; Wang, G X

2018-03-01

Diabetes has been recognized as a major risk factor to cause macrovascular diseases and plays a key role in aortic wall remodeling. However, the effects of diabetes on elastic properties of aortas remain largely unknown and quantitative mechanical data are lacking. Thirty adult rabbits (1.6-2.2 kg) were collected and the type 1 diabetic rabbit model was induced by injection of alloxan. A total of 15 control and 15 diabetic rabbit (abdominal) aortas were harvested. Uniaxial and biaxial tensile tests were performed to measure ultimate tensile strength and to characterize biaxial mechanical behaviors of the aortas. A material model was fitted to the biaxial experimental data to obtain constitutive parameters. Histological and mass fraction analyses were performed to investigate the underlying microstructure and dry weight percentages of elastin and collagen in the control and the diabetic aortas. No statistically significant difference was found in ultimate tensile strength between the control and the diabetic aortas. Regarding biaxial mechanical responses, the diabetic aortas exhibited significantly lower extensibility and significantly higher tissue stiffness than the control aortas. Notably, tissue stiffening occurred in both circumferential and axial directions for the diabetic aortas; however, mechanical anisotropy does not change significantly. The material model was able to fit biaxial experimental data very well. Histology showed that a number of isolated foam cells were embedded in the diabetic aortas and hyperplasia of collagen was identified. The dry weight percentages of collagen within the diabetic aortas increased significantly as compared to the control aortas, whereas no significant change was found for that of elastin. Our data suggest that the diabetes impairs elastic properties and alters microstructure of the aortas and consequently, these changes may further contribute to complex aortic wall remodeling.

Radiotherapy-induced aortic valve disease associated with porcelain aorta

International Nuclear Information System (INIS)

Daitoku, Kazuyuki; Fukui, Kozo; Ichinoseki, Ikkoh; Munakata, Mamoru; Takahashi, Shoichi; Fukuda Ikuo

2004-01-01

Mediastinal irradiation has been reported to induce cardiac disease such as pericarditis, valvular dysfunction, conduction abnormalities, accelerated arteriosclerosis of the coronary arteries, and also calcifications of the ascending aorta. We herein describe a case of radiotherapy-induced porcelain aorta and aortic valve disease and their surgical treatment. The patient was diagnosed with myasthenia gravis (MG) in 1965 (Osserman's type II), and mediastinal irradiation was performed in 1970 for treatment of thymic tumor associated with MG. Thirty years after radiation therapy, complete atrioventricular block and aortic valve disease with severe calcification of the ascending aorta and aortic arch (porcelain aorta) were detected on echo cardiogram and cardiac catheterization. A permanent pacemaker was implanted via the left subclavian vein and aortic valve replacement was performed under extracorporeal circulation established by selective cerebral perfusion and balloon occlusion instead of aortic cross-clamping. As no risk factors of arteriosclerosis such as hypercholesterolemia, hyperglycemia and hypertension were apparent, we concluded that the aortic valve disease and porcelain aorta were primarily induced by radiotherapy. (author)

Turner Syndrome in Girls Presenting with Coarctation of the Aorta.

Science.gov (United States)

Eckhauser, Aaron; South, Sarah T; Meyers, Lindsay; Bleyl, Steven B; Botto, Lorenzo D

2015-11-01

To evaluate the frequency of Turner syndrome in a population-based, statewide cohort of girls with coarctation of the aorta. The Utah Birth Defects Network was used to ascertain a cohort of girls between 1997 and 2011 with coarctation of the aorta. Livebirths with isolated coarctation of the aorta or transverse arch hypoplasia were included and patients with complex congenital heart disease not usually seen in Turner syndrome were excluded. Of 244 girls with coarctation of the aorta, 77 patients were excluded, leaving a cohort of 167 girls; 86 patients (51%) had chromosomal studies and 21 (12.6%) were diagnosed with Turner syndrome. All patients were diagnosed within the first 4 months of life and 5 (24%) were diagnosed prenatally. Fifteen patients (71%) had Turner syndrome-related findings in addition to coarctation of the aorta. Girls with mosaicism were less likely to have Turner syndrome-associated findings (3/6 mosaic girls compared with 12/17 girls with non-mosaic 45,X). Twelve girls (57%) diagnosed with Turner syndrome also had a bicommissural aortic valve. At least 12.6% of girls born with coarctation of the aorta have karyotype-confirmed Turner syndrome. Such a high frequency, combined with the clinical benefits of an early diagnosis, supports genetic screening for Turner syndrome in girls presenting with coarctation of the aorta. Copyright © 2015 Elsevier Inc. All rights reserved.

MR imaging of the thoracic aorta in patients with Marfan syndrome

International Nuclear Information System (INIS)

Sommerhoff, B.A.; Sechtem, U.P.; Schiller, N.B.; Higgins, C.B.

1986-01-01

Gated MR imaging was used to evaluate the thoracic aorta in 11 with Marfan syndrome, eight patients with aneurysm of the ascending aorta, and 20 healthy subjects. The aortic diameter was measured on transverse and sagittal images at the levels of the sinuses of Valsalva, the caudal portion of the ascending aorta, the prearch region, the middle arch, and the descending aorta. The sinus of Valsalva-prearch region aortic diameter ratio in patients with Marfan syndrome was significantly greater than in the two other groups, indicating the characteristic shape of the Maranoid aorta. MR imaging allows definitive measurements' of aortic dimensions and is a valuable noninvasive method for monitoring the course of aortic enlargement

Intimal permeability evaluated in a short-term organ culture of diabetic guinea pig aorta

International Nuclear Information System (INIS)

Schlosser, M.J.; Verlangieri, A.J.

1988-01-01

A novel short-term organ culture system was used to evaluate intimal permeability changes by measuring aortic [ 14 C]methylated albumin accumulation. Aortic plugs were removed from the upper thoracic aorta of male guinea pigs and maintained in serum-free media. The accumulation of [ 14 C]albumin in the intimal-medial layer was determined after a 5 h incubation. In preliminary studies, albumin recovered from intimal-injured aortic plugs was significantly greater than those from non-injured plugs. Aortic plugs from streptozotocin-treated guinea pigs, diabetic for 3 weeks, also accumulated significantly more [ 14 C]albumin than plugs from nondiabetic controls. Histological changes were not observed in the aorta of either the diabetic or control group. A strong significant inverse correlation was found between plasma ascorbic acid levels and [ 14 C]-activity recovered from aortic plugs. This study demonstrates a simple and rapid method for assessing aortic permeability changes under a well-defined in vitro system, and suggests that vascular permeability changes in the streptozotocin-diabetic guinea pig may be associated with an ascorbic acid deficit

Phantom position dependence

International Nuclear Information System (INIS)

Thorson, M.R.; Endres, G.W.R.

1981-01-01

Sensitivity of the Hanford dosimeter response to its position relative to the phantom and the neutron source has always been recognized. A thorough investigation was performed to quantify dosimeter response according to: (a) dosimeter position on phantom, (b) dosimeter distance from phantom, and (c) angular relationship of dosimeter relative to neutron source and phantom. Results were obtained for neutron irradiation at several different energies

Spiral blood flow in aorta-renal bifurcation models.

Science.gov (United States)

Javadzadegan, Ashkan; Simmons, Anne; Barber, Tracie

2016-01-01

The presence of a spiral arterial blood flow pattern in humans has been widely accepted. It is believed that this spiral component of the blood flow alters arterial haemodynamics in both positive and negative ways. The purpose of this study was to determine the effect of spiral flow on haemodynamic changes in aorta-renal bifurcations. In this regard, a computational fluid dynamics analysis of pulsatile blood flow was performed in two idealised models of aorta-renal bifurcations with and without flow diverter. The results show that the spirality effect causes a substantial variation in blood velocity distribution, while causing only slight changes in fluid shear stress patterns. The dominant observed effect of spiral flow is on turbulent kinetic energy and flow recirculation zones. As spiral flow intensity increases, the rate of turbulent kinetic energy production decreases, reducing the region of potential damage to red blood cells and endothelial cells. Furthermore, the recirculation zones which form on the cranial sides of the aorta and renal artery shrink in size in the presence of spirality effect; this may lower the rate of atherosclerosis development and progression in the aorta-renal bifurcation. These results indicate that the spiral nature of blood flow has atheroprotective effects in renal arteries and should be taken into consideration in analyses of the aorta and renal arteries.

Intramural hemorrhage of the thoracic aorta - imaging features and differential diagnosis; Das intramurale Haematom der thorakalen Aorta: Bildgebende Diagnostik und Differentialdiagnose

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Sommer, T. [Bonn Univ. (Germany) Radiologische Klinik; Abu-Ramadan, D. [Bonn Univ. (Germany). Klinik fuer Herz- und Gefaesschirurgie; Busch, M. [Bonn Univ. (Germany) Radiologische Klinik; Bierhoff, E. [Bonn Univ. (Germany). Pathologische Inst.; Kreft, B. [Bonn Univ. (Germany) Radiologische Klinik; Kuhl, C. [Bonn Univ. (Germany) Radiologische Klinik; Lutterbey, G. [Bonn Univ. (Germany) Radiologische Klinik; Keller, E. [Bonn Univ. (Germany) Radiologische Klinik; Schild, H. [Bonn Univ. (Germany) Radiologische Klinik

1996-09-01

Purpose: Aortic wall thickening due to intramural hemorrhage may be the only sign of aortic dissection. The aim of this study was to evaluate the incidence, imaging features and differential diagnoses of intramural hemorrhage (IMH) of the thoracic aorta. Methods: 98 patients with clinically suspected aortic dissection were investigated via Spiral-CT and MRT. Diagnosis of IMH based on the presence of smooth crescentic or concentric wall thickening over a longer segment of the thoracic aorta without flow visualization and without compression or distortion of the aortic lumen. Results: 69 patients had classic aortic dissections and 7 patients were diagnosed to have IMH of the thoracic aorta. One patient with IMH of the ascending aorta died of aortic rupture and subsequent pericardial tamponade 12 hours after onset of symptoms. In one patient with IMH of the descending aorta on initial examination, there was a progression of overt aortic dissection at follow-up after three weeks. In two patients with IMH of the descending aorta, wall thickening decreased in size at follow-up (10-15 weeks), whereas in one patient it remained unchanged. Conclusion: IMH of the aorta should be considered a precursor of aortic dissection. At follow-up IMH may decrease in size, rupture or progress to overt aortic dissection. (orig.) [Deutsch] Ziel: Eine aortale Wandverdichtung als Ausdruck eines intramuralen Haematoms kann die einzige Manifestation einer Aortendissektion sein. Ziel dieser Arbeit war die Evaluierung der Inzidenz, bildgebenden Aspekte und Differentialdiagnosen dieses in der deutschsprachigen Literatur wenig bekannten Krankheitsbildes. Methode: 98 Patienten mit klinischem Verdacht auf eine Aortendissektion wurden MR- und computertomographisch untersucht. Kriterium fuer das Vorliegen eines intramuralen Haematoms war der Nachweis einer laengerstreckigen aortalen Wandverdickung ohne Flussnachweis sowie ohne Konfigurationsaenderung des aortalen Lumens. Ergebnisse: 69 Patienten

The Effect of Chlorpyrifos on Isolated Thoracic Aorta in Rats

Directory of Open Access Journals (Sweden)

Ebru Yıldırım

2013-01-01

Full Text Available This study investigated the effect of chlorpyrifos on thoracic aorta and on the level of NO in plasma and aorta. The effect of chlorpyrifos on thoracic aorta in organ bath was determined in 10 rats. Another 45 rats were assigned to 3 groups with 15 rats each: control group 1 received distilled water, control group 2 was given corn oil, and the last group was given 13.5 mg/kg chlorpyrifos dissolved in corn oil every other day for 8 weeks orally. Chlorpyrifos (10−10 M–10−5 M showed no effect on isolated thoracic aorta. Plasma AChE activity was decreased, while LDH, ALT, GGT, and AST activities were increased in chlorpyrifos group compared to control groups. Plasma NO level was increased in chlorpyrifos group compared to control groups. iNOS expression was present in all groups in the cytoplasm of the endothelia and in the smooth muscle cells of aorta. According to semiquantitative histomorphological analysis, iNOS immunopositive reactions were seen in the decreasing order in chlorpyrifos, control 2, and control 1 groups. eNOS immunopositive reactions were observed in the endothelial cell cytoplasm, rarely in the subintimal layer, and the smooth muscle cells of aorta. There were no differences among the groups in terms of eNOS immunostaining. In conclusion, chlorpyrifos induced NO production in aorta following an increase in NOS expression.

The Effect of Chlorpyrifos on Isolated Thoracic Aorta in Rats

Science.gov (United States)

Yıldırım, Ebru; Baydan, Emine; Kanbur, Murat; Kul, Oğuz; Çınar, Miyase; Ekici, Hüsamettin; Atmaca, Nurgül

2013-01-01

This study investigated the effect of chlorpyrifos on thoracic aorta and on the level of NO in plasma and aorta. The effect of chlorpyrifos on thoracic aorta in organ bath was determined in 10 rats. Another 45 rats were assigned to 3 groups with 15 rats each: control group 1 received distilled water, control group 2 was given corn oil, and the last group was given 13.5 mg/kg chlorpyrifos dissolved in corn oil every other day for 8 weeks orally. Chlorpyrifos (10−10 M–10−5 M) showed no effect on isolated thoracic aorta. Plasma AChE activity was decreased, while LDH, ALT, GGT, and AST activities were increased in chlorpyrifos group compared to control groups. Plasma NO level was increased in chlorpyrifos group compared to control groups. iNOS expression was present in all groups in the cytoplasm of the endothelia and in the smooth muscle cells of aorta. According to semiquantitative histomorphological analysis, iNOS immunopositive reactions were seen in the decreasing order in chlorpyrifos, control 2, and control 1 groups. eNOS immunopositive reactions were observed in the endothelial cell cytoplasm, rarely in the subintimal layer, and the smooth muscle cells of aorta. There were no differences among the groups in terms of eNOS immunostaining. In conclusion, chlorpyrifos induced NO production in aorta following an increase in NOS expression. PMID:23878805

Coarctation of the aorta

Science.gov (United States)

... the legs is usually weaker than in the arms. Blood pressure is usually higher in the arms after infancy. ... be used to see if there are any differences in blood pressure in different areas of the aorta. Treatment Most ...

In vitro vascular effects produced by crude aqueous extract of green marine algae, Cladophora patentiramea (Mont.) Kützing, in aorta from normotensive rats.

Science.gov (United States)

Lim, Yee-Ling; Mok, Shiueh-Lian

2010-01-01

To investigate the antihypertensive activity of aqueous extracts obtained from Malaysian coastal seaweeds and to determine the pharmacological mechanisms of the extracts on rat aorta in vitro. The antihypertensive activity of 11 species of seaweeds (5 brown, 1 red and 5 green algae) were tested by cumulative addition of the extracts to phenylephrine (PE)-precontracted Wistar-Kyoto (WKY) aortic rings in in vitro isometric contraction studies. Mechanisms for vasorelaxant effect were investigated in the presence of various antagonists. Of the 11 species tested, 2 showed a vasorelaxant effect. Further investigation of the mechanisms of action of the aqueous extract of green alga, Cladophora patentiramea (AECP),showed that the vascular relaxant effect was endothelium- and concentration-dependent. A maximum relaxation of 45.8 +/- 4.6% (n = 8, p < 0.001) was obtained at 0.1 mg/ml of extract, after which the response was found to reduce in a concentration-dependent manner to 15.7 +/- 4.9% (n = 8, p < 0.001) at the highest extract concentration tested. Pretreatment of endothelium-intact aortic rings with Nomega-nitro-L-arginine methyl ester (L-NAME, 30 microM), (1)H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10 microM) and methylene blue (100 microM) resulted in a complete blockade of AECP-induced vasorelaxation. However, the relaxant effects of the extract were not blocked by atropine (1 microM), indomethacin (10 microM) and glibenclamide (10 microM), although the maximum relaxant responses were enhanced in the presence of glibenclamide. Our data showed that the in vitro vascular relaxant effect of AECPwas mediated through endothelium-dependent nitric oxide-cGMP pathway, and was not associated with the release of vasodilator prostaglandins, activation of muscarinic receptors, or ATP-sensitive potassium channels opening. Copyright 2010 S. Karger AG, Basel.

Evaluation of diseases of the aorta with ultrafast CT

International Nuclear Information System (INIS)

Eldredge, W.J.; Flicker, S.; Altin, R.S.; Naidech, H.J.

1987-01-01

Ultrafast CT offers several advantages over standard CT for imaging of various congenital and acquired diseases of the aorta. Scan acquisition rates of 50 msec permit evaluation of the entire aorta following a single peripheral intravenous injection of iodinated contrast medium. Pathologic aortic flow patterns may also be defined using an ECG triggered ''flow'' mode, adding another dimension to CT evaluation of the aorta. The papers shows examples of a variety of aortic diseases, including coarctation, Marfan syndrome, atherosclerotic aneurysm, dissection, and postoperative abnormalities. The advantages of the modality are stressed

Intravascular enhancement with identical iodine delivery rate using different iodine contrast media in a circulation phantom.

Science.gov (United States)

Mihl, Casper; Wildberger, Joachim E; Jurencak, Tomas; Yanniello, Michael J; Nijssen, Estelle C; Kalafut, John F; Nalbantov, Georgi; Mühlenbruch, Georg; Behrendt, Florian F; Das, Marco

2013-11-01

Both iodine delivery rate (IDR) and iodine concentration are decisive factors for vascular enhancement in computed tomographic angiography. It is unclear, however, whether the use of high-iodine concentration contrast media is beneficial to lower iodine concentrations when IDR is kept identical. This study evaluates the effect of using different iodine concentrations on intravascular attenuation in a circulation phantom while maintaining a constant IDR. A circulation phantom with a low-pressure venous compartment and a high-pressure arterial compartment simulating physiological circulation parameters was used (heart rate, 60 beats per minute; stroke volume, 60 mL; blood pressure, 120/80 mm Hg). Maintaining a constant IDR (2.0 g/s) and a constant total iodine load (20 g), prewarmed (37°C) contrast media with differing iodine concentrations (240-400 mg/mL) were injected into the phantom using a double-headed power injector. Serial computed tomographic scans at the level of the ascending aorta (AA), the descending aorta (DA), and the left main coronary artery (LM) were obtained. Total amount of contrast volume (milliliters), iodine delivery (grams of iodine), peak flow rate (milliliter per second), and intravascular pressure (pounds per square inch) were monitored using a dedicated data acquisition program. Attenuation values in the AA, the DA, and the LM were constantly measured (Hounsfield unit [HU]). In addition, time-enhancement curves, aortic peak enhancement, and time to peak were determined. All contrast injection protocols resulted in similar attenuation values: the AA (516 [11] to 531 [37] HU), the DA (514 [17] to 531 [32] HU), and the LM (490 [10] to 507 [17] HU). No significant differences were found between the AA, the DA, and the LM for either peak enhancement (all P > 0.05) or mean time to peak (AA, 19.4 [0.58] to 20.1 [1.05] seconds; DA, 21.1 [1.0] to 21.4 [1.15] seconds; LM, 19.8 [0.58] to 20.1 [1.05] seconds). This phantom study demonstrates that

Evaluation of factors influencing arterial Doppler waveforms in an in vitro flow phantom

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Sung, Chang Kyu [Dept. of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul (Korea, Republic of); Lee, Kyoung Ho [Dept. of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of); Kim, Seung Hyup [Dept. of Radiology and the Institute of Radiation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)

2017-01-15

The aim of this study was to investigate factors that influence arterial Doppler waveforms in an in vitro phantom to provide a more accurate and comprehensive explanation of the Doppler signal. A flow model was created using a pulsatile artificial heart, rubber or polyethylene tubes, a water tank, and a glass tube. Spectral Doppler tracings were obtained in multiple combinations of compliance, resistance, and pulse rate. Peak systolic velocity, minimum diastolic velocity, resistive index (RI), pulsatility index, early systolic acceleration time, and acceleration index were measured. On the basis of these measurements, the influences of the variables on the Doppler waveforms were analyzed. With increasing distal resistance, the RI increased in a relatively linear relationship. With increasing proximal resistance, the RI decreased. The pulsus tardus and parvus phenomenon was observed with a small acceleration index in the model with a higher grade of stenosis. An increase in the distal resistance masked the pulsus tardus and parvus phenomenon by increasing the acceleration index. Although this phenomenon occurred independently of compliance, changes in the compliance of proximal or distal tubes caused significant changes in the Doppler waveform. There was a reverse relationship between the RI and the pulse rate. Resistance and compliance can alter the Doppler waveforms independently. The pulse rate is an extrinsic factor that also influences the RI. The compliance and distal resistance, as well as proximal resistance, influence the pulsus tardus and parvus phenomenon.

Identification of critical areas of carotid stent navigation by measurement of resistive forces in vitro, using silicone phantoms

International Nuclear Information System (INIS)

Sengupta, A.; Kesavadas, T.; Baier, R.E.; Hoffmann, K.R.; Schafer, S.

2007-01-01

Manipulation of surgical tools in neuro-endovascular surgery presents problems that are unique to this procedure. Navigating tools through arterial complexities without appropriate visual or force feedback information often causes tool snagging, plaque dislocations and formation of thrombosis from the damage of the arterial wall by the tools. Identifying the critical areas in the vasculature during navigation of endovascular tools, will not only ensure safer surgical planning but also reduce risks of vessel damage. In the present research, resistive forces of stent navigation were measured in-vitro using silicone phantoms and clinically relevant surgical devices. The patterns of variation of the forces along the path of the stent movement were analyzed and mapped along the path of stent movement using a color code. It was observed that the forces changed along the length of the vessel, independent of the insertion length but based on the curvature of the vessel and the contact area of the device in the vessel lumen. (orig.)

Surgical treatment of penetrating atherosclerotic ulcer of the descending aorta

Directory of Open Access Journals (Sweden)

Kovačević Pavle

2013-01-01

Full Text Available Introduction. The term “penetrating atherosclerotic ulcer” (PAU of the aorta describes the condition in which ulceration of an aortic atherosclerotic lesion penetrates the internal elastic lamina into media. PAU is a high-risk lesion due to its deleterious effects on the integrity of aortic wall, with potentially fatal outcome. Case report. A patient with intensive, sharp chest pain irradiating to the back but with no signs of myocardial ischemia on an electrocardiogram was referred to our hospital. Transthoracic echocardiography showed no pathological changes of the ascending aorta. However, multislice computed tomography (CT showed an aortic ulcer with varying degree of the subadventitial hemorrhage in the region of the thoracic aorta at the level of Th 8-9. Due to imminent rupture of the penetrating aortic ulcer, the patient was promptly prepared for surgery. A 15 cm long subadventitial hematoma was found intraoperatively in the right posterolateral aspect of the descending aorta, 5 cm above the diaphragm and 7 cm below the origin of the left subclavial artery. The affected segment of the aorta was resected, followed by an inlay aortic reconstruction with a Dacron tube graft of 24 mm. Control CT revealed satisfactory reconstruction of the descending aorta. Conclusion. PAU is a rare, but potentially fatal disease. Open surgery in patients with PAU is an effective treatment strategy, although endovascular treatment options are emerging.

Anomalous Posterior Intercostal Arterial Trunk Arising From the Abdominal Aorta

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Jie, Bing, E-mail: jbshh@163.com; Yu, Dong, E-mail: yudong-mail@126.com; Jiang, Sen, E-mail: jasfly77@vip.163.com [Tongji University School of Medicine, Department of Radiology, Shanghai Pulmonary Hospital (China)

2016-04-15

A common trunk of the ipsilateral posterior intercostal artery (PIA) arising from the thoracic aorta is usually an anatomical variation. However, a common trunk of bilateral posterior intercostal arterial trunk (PIAT) arising from the abdominal aorta is rare. It is important to recognize this anatomical variation of PIA when performing interventional radiological procedures. We present a rare case of an anomalous PIAT that originated from the abdominal aorta in a patient with hemoptysis caused by tuberculosis sequelae. Bilateral 4th to 11th PIAs arose from a common trunk and the trunk arising from the posterior aspect of the abdominal aorta at the level of T12/L1 intervertebral space. The pathological right 4th and 5th PIAs and bronchial arteries were embolized. Hemoptysis has been controlled for 3 months.

Presence of plasma proteins facilitates the uptake of 125I-thrombin by the rabbit thoracic aorta endothelium in vitro

International Nuclear Information System (INIS)

Hatton, M.W.; Moar, S.L.

1986-01-01

Various purified proteins, protein derivatives and two polysaccharides were added individually to a physiological medium in order to effect uptake of 125 I-thrombin by the rabbit aorta endothelium. Over a wide range of concentration (0.004-40 mg/ml), the presence of either purified rabbit or bovine albumin during thrombin uptake encouraged an increase (70-110%) in 125 I-thrombin binding by the endothelium and subendothelium compared to uptake by aorta segments in the absence of added protein. Pretreatment of aorta segments with albumin before incubation with 125 I-thrombin in the absence of albumin did not encourage thrombin uptake to the same extent as having 125 I-thrombin and albumin together. Purified human transferrin, rabbit IgG, chicken ovalbumin or denatured bovine casein could replace albumin to produce a similar enhancement of thrombin uptake. Replacing active concentrations of albumin by either reduced-carboxymethylated albumin, defatted albumin, plasmin-treated or thermolysin-treated albumin also caused an increase (50-130%) in thrombin binding, whereas replacement by acid-hydrolysed albumin or with polyglutamic acid was either ineffective or even inhibitory. Lysine-modified or arginine-modified albumins caused a small enhancement (14-32%) and no enhancement of thrombin uptake, respectively. Dextran, at low concentration (0.04-0.4 mg/ml) did not influence thrombin uptake, and at higher concentration (4-40 mg/ml) caused a decrease in uptake by both the endothelium and subendothelial layers. Low concentration of dextran sulphate inhibited thrombin uptake to 20-30% of control values. These data express the importance of accompanying protein in the response of the vascular endothelium during binding of thrombin. The possibility that other protein-cell interactions may be similarly influenced by macromolecular solutes is also discussed

Digital subtraction angiography of the thoracic aorta

International Nuclear Information System (INIS)

Grossman, L.B.; Buonocore, E.; Modic, M.T.; Meaney, T.F.

1984-01-01

Forty-three patients with acquired and congenital abnormalities of the thoracic aorta were studied using digital subtraction angiography (DSA) after an intravenous bolus injection of 40 ml of contrast material. Abnormalities studied included coarctation, pseudocoarctation, Marfan syndrome, cervical aorta, double aortic arch, aneurysm, dissection, and tumor. Twenty-four patients also had conventional angiography. DSA was accurate in 95% of cases; in the other 5%, involving patients with acute type I dissection, the coronary arteries could not be seen. The authors concluded that in 92% of their patients, DSA could have replaced the standard aortogram

Pseudoprominent aorta: Radiographic findings and CT correlation

International Nuclear Information System (INIS)

Brown, K.T.; Shepard, J.A.O.; Stewart, W.J.

1985-01-01

The presence of a persistent left-sided superior vena cava (LSVC) in the absence of a right-sided superior vena cava (RSVC) may be suspected on a posteroanterior (PA) chest radiograph because of a prominent-appearing ascending aorta, which results from the absence of the RSVC. In the absence of an RSVC, the right upper lobe abuts and outlines the course of the ascending aorta, allowing better demonstration of its profile. This report describes a patient with this finding on a PA chest radiograph. Computed tomographic correlation is presented

Digital subtraction angiography of the thoracic aorta

Energy Technology Data Exchange (ETDEWEB)

Grossman, L.B.; Buonocore, E.; Modic, M.T.; Meaney, T.F.

1984-02-01

Forty-three patients with acquired and congenital abnormalities of the thoracic aorta were studied using digital subtraction angiography (DSA) after an intravenous bolus injection of 40 ml of contrast material. Abnormalities studied included coarctation, pseudocoarctation, Marfan syndrome, cervical aorta, double aortic arch, aneurysm, dissection, and tumor. Twenty-four patients also had conventional angiography. DSA was accurate in 95% of cases; in the other 5%, involving patients with acute type I dissection, the coronary arteries could not be seen. The authors concluded that in 92% of their patients, DSA could have replaced the standard aortogram.

Pseudoprominent aorta: Radiographic findings and CT correlation

Energy Technology Data Exchange (ETDEWEB)

Brown, K.T.; Shepard, J.A.O.; Stewart, W.J.

1985-05-01

The presence of a persistent left-sided superior vena cava (LSVC) in the absence of a right-sided superior vena cava (RSVC) may be suspected on a posteroanterior (PA) chest radiograph because of a prominent-appearing ascending aorta, which results from the absence of the RSVC. In the absence of an RSVC, the right upper lobe abuts and outlines the course of the ascending aorta, allowing better demonstration of its profile. This report describes a patient with this finding on a PA chest radiograph. Computed tomographic correlation is presented.

Abdominal aorta coarctation: The first three case reports in our literature

OpenAIRE

Gajin Predrag; Tanasković Slobodan; Nenezić Dragoslav; Ilijevski Nenad; Radak Đorđe

2010-01-01

Introduction. Congenital coarctation of the thoracic aorta at the ligamentum arteriosum or the aortic arch is well recognized. But a much less common variety (0.5-2.0%) of aortic coarctation is located in the distal thoracic aorta or abdominal aorta or both and is often called 'middle aortic syndrome' or 'midaortic dysplastic syndrome'. This represents serious pathological condition and indicates multidisciplinary therapy approach. Outline of Cases. From 1996 to 2007, at the Vascular Surgery ...

Phantom pain and phantom sensations in upper limb amputees : an epidemiological study

NARCIS (Netherlands)

Kooijman, CM; Dijkstra, PU; Geertzen, JHB; Elzinga, A; van der Schans, CP

Phantom pain in subjects with an amputated limb is a well-known problem. However, estimates of the prevalence of phantom pain differ considerably in the literature. Various factors associated with phantom pain have been described including pain before the amputation, gender, dominance, and time

Individual virtual phantom reconstruction for organ dosimetry based on standard available phantoms

International Nuclear Information System (INIS)

Babapour Mofrad, F.; Aghaeizadeh Zoroofi, R.; Abbaspour Tehran Fard, A.; Akhlaghpoor, Sh.; Chen, Y. W.; Sato, Y.

2010-01-01

In nuclear medicine application often it is required to use computational methods for evaluation of organ absorbed dose. Monte Carlo Simulation and phantoms have been used in many works before. The shape, size and volume In organs are varied, and this variation will produce error in dose calculation if no correction is applied. Materials and Methods: A computational framework for constructing individual phantom for dosimetry was performed on five liver CT scan data sets of Japanese normal individuals. The Zubal phantom was used as an original phantom to be adjusted by each individual data set. This registration was done by Spherical Harmonics and Thin-Plate Spline methods. Hausdorff distance was calculated for each case. Results: Result of Hausdorff distance for five lndividual phantoms showed that before registration ranged from 140.9 to 192.1, and after registration it changed to 52.5 to 76.7. This was caused by Index similarity ranged from %56.4 to %70.3. Conclusion: A new and automatic three-dimensional (3D) phantom construction approach was-suggested for individual internal dosimetry simulation via Spherical Harmonics and Thin-Plate Spline methods. The results showed that the Individual comparable phantom can be calculated with acceptable accuracy using geometric registration. This method could be used for race-specific statistical phantom modeling with major application in nuclear medicine for absorbed dose calculation.

The problem of calcified ascending aorta during aortocoronary bypass

Directory of Open Access Journals (Sweden)

Nežić Duško G.

2004-01-01

Full Text Available Heavily calcified ascending aorta significantly increased morbidity and lethality during open-heart surgery. Cannulation and clamping (partial or total of severely atherosclerotic ascending aorta can easily cause damage and rupture of aortic wall, with consequential distal (often fatal embolization with atheromatous debris (brain, myocardium. From June 1998. until June 2000, 11 of 2 136 (0.5% patients who underwent coronary artery bypass grafting were with the severe atheromatous ascending aorta. The site of cannulation was in the aortic arch in three patients (aorta was occluded with Foley catheter in one case, and single clamp technique was used in the other two cases. The femoral artery was the cannulation site in other five cases. Profound hypothermia, ventricular fibrillation, and circulatory arrest, with no cross-clamping or cardioplegia, were used in three patients. Two patients were operated on with extracorporeal circulation, one in normothermia, on the beating heart, the other in moderate hypothermia, on fibrillating heart. In three patients myocardial revascularization was performed on the beating heart, in normothermia, without extracorporeal circulation. Postoperative course was uneventful in all 11 patients. Neither atheroembolism in the peripheral organs, nor atheroembolism of the extramities occurred. The proposed surgical approaches have the potential to reduce the prevalence of stroke and systemic embolization associated with coronary artery bypass grafting in patients with heavily calcified ascending aorta. This result was achieved due to the applied modifications of standard cardiosurgical technique.

Real-time phase contrast magnetic resonance imaging for assessment of haemodynamics: from phantom to patients

Energy Technology Data Exchange (ETDEWEB)

Traber, Julius; Wurche, Lennart; Dieringer, Matthias A.; Utz, Wolfgang; Knobelsdorff-Brenkenhoff, Florian von; Schulz-Menger, Jeanette [Max-Delbrueck-Centrum and Charite -Medical University Berlin and HELIOS Klinikum Berlin-Buch, Department of Cardiology and Nephrology, Working Group on Cardiovascular Magnetic Resonance Imaging, Experimental and Clinical Research Center, Berlin (Germany); Greiser, Andreas [Siemens AG Healthcare Sector, Erlangen (Germany); Jin, Ning [Siemens Medical Solutions USA, Inc., Columbus, OH (United States)

2016-04-15

Assessment of haemodynamics is crucial in many cardiac diseases. Phase contrast MRI (PC-MRI) can accurately access it. Arrhythmia is a major limitation in conventional segmented PC-MRI (SEG). A real-time PC-MRI sequence (RT) could overcome this. We validated RT by comparing to SEG. A prototype RT using shared velocity encoding was tested against SEG at 1.5 T in a flow phantom and consecutively included patients with (n = 55) or without (n = 59) aortic valve disease. In patients with atrial fibrillation (Afib, n = 15), only RT was applied. Phantom: PC images were acquired in front of and behind an interchangeable aortic-stenosis-like inlay. Mean velocity and flow were quantified. Patients: PC images were acquired in the ascending aorta, pulmonary trunk and superior caval vein. Peak velocity, stroke volume and regurgitant fraction were quantified. Phantom: Mean velocities (11 ± 1 to 207 ± 10 cm/s) and flow correlated closely between SEG and RT (r ≥ 0.99, ICC ≥ 0.98, p < 0.0005). Patients without AVD or with aortic regurgitation: Concordance of SEG and RT was excellent regarding peak velocities, stroke volumes (r ≥ 0.91, ICC ≥ 0.94, p < 0.0005) and regurgitant fractions (r = 0.95, ICC = 0.95, p < 0.0005). RT was feasible in all patients with Afib. The real-time sequence is accurate compared to conventional segmented PC-MRI. Its applicability in Afib was shown. Real-time PC-MRI might become a valuable tool in arrhythmia. (orig.)

Improved protein extraction and protein identification from archival formalin-fixed paraffin-embedded human aortas.

Science.gov (United States)

Fu, Zongming; Yan, Kun; Rosenberg, Avraham; Jin, Zhicheng; Crain, Barbara; Athas, Grace; Heide, Richard S Vander; Howard, Timothy; Everett, Allen D; Herrington, David; Van Eyk, Jennifer E

2013-04-01

Evaluate combination of heat and elevated pressure to enhance protein extraction and quality of formalin-fixed (FF), and FF paraffin-embedded (FFPE) aorta for proteomics. Proteins were extracted from fresh frozen aorta at room temperature (RT). FF and FFPE aortas (3 months and 15 years) were extracted at RT, heat alone, or a combination of heat and high pressure. Protein yields were compared, and digested peptides from the extracts were analyzed with MS. Combined heat and elevated pressure increased protein yield from human FF or FFPE aorta compared to matched tissues with heat alone (1.5-fold) or at RT (8.3-fold), resulting in more proteins identified and with more sequence coverage. The length of storage did adversely affect the quality of proteins from FF tissue. For long-term storage, aorta was preserved better with FFPE than FF alone. Periostin and MGF-E8 were demonstrated suitable for MRM assays from FFPE aorta. Combination of heat and high pressure is an effective method to extract proteins from FFPE aorta for downstream proteomics. This method opens the possibility for use of archival and often rare FFPE aortas and possibly other tissues available to proteomics for biomarker discovery and quantification. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Valve-sparing root and ascending aorta replacement after heart transplantation.

Science.gov (United States)

Elhenawy, Abdelsalam M; Feindel, Christopher M; Ross, Heather; Butany, Jagdish; Yau, Terrence M

2012-12-01

A 45-year-old female underwent heart transplantation 17 years ago, with a heart from a 15-year-old donor. Recently, she had developed an aneurysm of the donor aortic root and ascending aorta, with severe aortic insufficiency. Two surgical options were considered; retransplantation versus replacement of the aortic root and ascending aorta. A valve-sparing replacement of the aortic root and ascending aortic aneurysm was performed. The donor aorta showed pathologic changes typical of Marfan syndrome. Nineteen months postoperatively, the patient remains in functional class I, with trivial aortic insufficiency. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Automated quantitative 3D analysis of aorta size, morphology, and mural calcification distributions

Energy Technology Data Exchange (ETDEWEB)

Kurugol, Sila, E-mail: sila.kurugol@childrens.harvard.edu; Come, Carolyn E.; Diaz, Alejandro A.; Ross, James C.; Washko, George R.; San Jose Estepar, Raul [Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts 02115 (United States); Kinney, Greg L.; Black-Shinn, Jennifer L.; Hokanson, John E. [Colorado School of Public Health, University of Colorado Denver, Aurora, Colorado 80045 (United States); Budoff, Matthew J. [Los Angeles Biomedical Research Center at Harbor and UCLA Medical Center, Torrance, California 90502 (United States)

2015-09-15

Purpose: The purpose of this work is to develop a fully automated pipeline to compute aorta morphology and calcification measures in large cohorts of CT scans that can be used to investigate the potential of these measures as imaging biomarkers of cardiovascular disease. Methods: The first step of the automated pipeline is aorta segmentation. The algorithm the authors propose first detects an initial aorta boundary by exploiting cross-sectional circularity of aorta in axial slices and aortic arch in reformatted oblique slices. This boundary is then refined by a 3D level-set segmentation that evolves the boundary to the location of nearby edges. The authors then detect the aortic calcifications with thresholding and filter out the false positive regions due to nearby high intensity structures based on their anatomical location. The authors extract the centerline and oblique cross sections of the segmented aortas and compute the aorta morphology and calcification measures of the first 2500 subjects from COPDGene study. These measures include volume and number of calcified plaques and measures of vessel morphology such as average cross-sectional area, tortuosity, and arch width. Results: The authors computed the agreement between the algorithm and expert segmentations on 45 CT scans and obtained a closest point mean error of 0.62 ± 0.09 mm and a Dice coefficient of 0.92 ± 0.01. The calcification detection algorithm resulted in an improved true positive detection rate of 0.96 compared to previous work. The measurements of aorta size agreed with the measurements reported in previous work. The initial results showed associations of aorta morphology with calcification and with aging. These results may indicate aorta stiffening and unwrapping with calcification and aging. Conclusions: The authors have developed an objective tool to assess aorta morphology and aortic calcium plaques on CT scans that may be used to provide information about the presence of cardiovascular

Noninvasive radiodiagnosis of aneurysms of the thoracic aorta

International Nuclear Information System (INIS)

Todua, F.I.; Petsko, A.P.; Arablinskij, A.V.; Kazanchyan, P.O.; Nikitaev, N.S.; Sultanaliev, T.A.

1990-01-01

The paper is concerned with analysis of the results of X-ray investigation of 45 patients with aneurysms of the distal part of the arch and descending part of the thoracic aorta. X-ray investigation helped to establish correct diagnosis of aneurysm of the aorta in 42 of 45 patients (93.3 %) on the basis of the detection of intense additional shadow formation in left pulmonary field, unseparable from the aortic shadow. The use of a new method of ultrasound diagnosis-duplex scanning-made it possible to establish the presence of aneurysm and to determine its sizes as well as to visualize the relation of the left subclavicular artery to aneurysm in 17 of 21 patients. CT-semiotics of aneurysms of the descending part of the thoracic aorta consisted in its dilatation over 3.5 cm, wall calcification, thrombosis of the cavity and change of the adjacent structures. Basing on the analysis of these signs correct diagnosis was established in 34 of 35 examinees (97.1 %)

Cilostazol enhances atorvastatin-induced vasodilation of female rat aorta during aging.

Science.gov (United States)

Nurullahoğlu-Atalık, K E; Kutlu, S; Solak, H; Koca, R Özen

2017-09-01

Statins have cholesterol-independent effects including an increased vascular nitric oxide activity and are commonly used by patients with cardiovascular disease. Such patients frequently have cardiovascular diseases, which may be treated with cilostazol, a platelet aggregation inhibitor. This study was designed to investigate whether combined use of cilostazol would increase the inhibitory effect of statin on vascular smooth muscle and how maturation would affect these responses. Female Wistar rats, aged 3-4 months (young) and 14-15 months (adult), were sacrificed by cervical dislocation and the thoracic aorta was dissected and cut into 3- to 4-mm-long rings. The rings were mounted under a resting tension of 1 g in a 20-ml organ bath filled with Krebs-Henseleit solution. Rings were precontracted with phenylephrine (10 -6  M), and the presence of endothelium was confirmed with acetylcholine (10 -6  M). Then, the concentration-response curves were obtained for atorvastatin alone (10 -10 to 3 × 10 -4  M; control) and in the presence of cilostazol (10 -6  M) in young and adult rat aortas. This experimental protocol was also carried out in aorta rings, which had been pretreated with N G -nitro-l-arginine methyl ester (l-NAME, 10 -4  M). Atorvastatin induced concentration-dependent relaxations in young and adult rat thoracic aorta rings precontracted with phenylephrine. The pIC 50 value of atorvastatin was significantly decreased in adult rat aortas. In addition, pretreatment of aortas with cilostazol enhanced the potency of atorvastatin in both young and adult aortas. Incubation with l-NAME did not completely eliminate the relaxations to atorvastatin in the presence of cilostazol. These results suggest that combined application of cilostazol with atorvastatin was significantly more potent than atorvastatin alone. Combined drug therapy may be efficacious in delaying the occurrence of cardiovascular events.

Abdominal aorta coarctation: The first three case reports in our literature

Directory of Open Access Journals (Sweden)

Gajin Predrag

2010-01-01

Full Text Available Introduction. Congenital coarctation of the thoracic aorta at the ligamentum arteriosum or the aortic arch is well recognized. But a much less common variety (0.5-2.0% of aortic coarctation is located in the distal thoracic aorta or abdominal aorta or both and is often called 'middle aortic syndrome' or 'midaortic dysplastic syndrome'. This represents serious pathological condition and indicates multidisciplinary therapy approach. Outline of Cases. From 1996 to 2007, at the Vascular Surgery Clinic of the Institute for Cardiovascular Diseases 'Dedinje', Belgrade, three patients were treated due to abdominal aorta coarctation, two females aged 55 and 50 and a 4-year-old child. The patients were treated surgically (by-pass with a prosthetic graft and patch angioplasty and endovascular-percutaneous transluminal angioplasty (PTA with and without a stent. The follow-up period was 3-70 months. In the 50-year-old patient, angiography showed severe narrowing of the suprarenal segment of the abdominal aorta. Thoraco-abdominal bypass with a 16 mm dacronic tubular graft was performed. In the 4-year-old patient angiography also showed a suprarenal aorta narrowing. In the first act patch angioplasty was performed and after PTA of the visceral arteries was done on several occasions. In the 55-year-old patient, after diagnostic angiography, infrarenal aorta coarctation was registered. PTA was performed with stent placement. All patients were asymptomatic on control check-ups. Conclusion. Abdominal coarctation is a pathological disease which is seldom found in vascular surgery. Angiography is of major importance for setting the diagnosis and for the control of the results of surgical and nonsurgical treatment. The combination of surgical and endovascular treatment in our patients showed very good results in the studied period.

Ramos colaterais parietais e terminais da aorta abdominal em Myocastor coypus (nutria Terminal and parietal colateral branches of the abdominal aorta in Myocastor coypus (nutria

Directory of Open Access Journals (Sweden)

Paulete de Oliveira Vargas Culau

2008-08-01

Full Text Available Neste estudo, utilizaram-se 30 nutrias, 15 fêmeas e 15 machos, com o sistema arterial aórtico-abdominal preenchido com látex 603, pigmentado em vermelho, e fixado em uma solução aquosa de formaldeído a 20%. A aorta abdominal emitiu de sua superfície dorsal de 6 a 8 artérias lombares únicas. Das artérias renais, direita e esquerda, originaram-se as artérias frênico-abdominal para irrigar parte do diafragma e da parede abdominal lateral cranial. A aorta abdominal lançou dorsalmente, a artéria sacral mediana, cranialmente a sua bifurcação em artérias ilíacas comuns. As artérias ilíacas comuns, ramos terminais da aorta abdominal, originaram as artérias ilíacas interna e externa. A artéria ilíaca interna distribuiu-se nas vísceras da cavidade pélvica. A artéria ilíaca externa emitiu uma artéria umbilical e, antes de alcançar o anel femoral, lançou a artéria circunflexa ilíaca profunda para a parede abdominal lateral, em seus dois terços caudais. A artéria ilíaca externa lançou o tronco pudendo-epigástrico, que originou a artéria epigástrica caudal, para a parede abdominal ventral e a artéria pudenda externa, que saiu pelo canal inguinal, para irrigar a genitália externa. Os ramos parietais diretos da aorta abdominal foram as artérias lombares e a artéria sacral mediana, enquanto as artérias frênico-abdominal, circunflexa ilíaca profunda e epigástrica caudal, foram ramos colaterais parietais indiretos. Os ramos terminais da artéria aorta abdominal foram as artérias ilíacas comuns com seus ramos, as artérias ilíacas interna e externa.For this study it was used 30 nutria, 15 females and 15 males, with its abdominal aorta system full filled with latex 603, stained in red, and fixed in an aqueous solution of formaldehyde 20%. The abdominal aorta emitted from its dorsal surface 6 to 8 single lumbar arteries. From the renal arteries, left and right, it has been originated the phrenicoabdominal arteries

Methanol fractionations of Catha edulis Frosk (Celastraceae) contracted Lewis rat aorta in vitro: a comparison between crimson and green leaves.

Science.gov (United States)

Mahmood, Samira Abdulla; Pavlovic, Dragan; Hoffmann, Ulrich

2009-05-07

The study investigated the effect of methanol extract and its fractionations obtained from Yemeni khat on the smooth muscle isometric tension in Lewis rat aortal ring preparations and compared the effects of the crimson and green leaves. Khat leaves were sorted into green (khat Light; KL) and crimson (khat Dark; KD) leaves, extracted with methanol, followed with solvent-solvent extraction (benzene, chloroform and ethylacetate). The contractile activity of the fractions was tested using aortal ring preparations. The control (phenylepherine contraction) methanol extracts contracted aortas at concentrations 250, 125 and 67.5 microg/ml buffer by 80.2%, 57.3%, 26.4% and 81.5%, 65.6%, 24.6% for KL and KD, respectively. Fractions of benzene (BF) and ethylacetate (EaF) contracted the aorta with 2 microgm, whereas, chloroform (ChF) with 1 microgm/1 ml buffer was less potent. The shape of contraction curve produced by EaF differed from that of ChF and BF of both (KL and KD). The EaF induced-contraction peaked after 3.3 +/- 0.94 mins, whereas those of BF and CHF peaked after 18.0 +/- 2.2, 19.7 +/- 0.94 mins, respectively. Pre-incubation with nifedipine (10(-6) M) insignificantly reduced the contraction induced by all fractionations, but prazosin (10(-6) M) reduced the contraction by 81.9%, 63.1%, 71.8% with p = 0.23, 0.09, 0.15 for BF, ChF and EaF of KL, respectively. It significantly reduced contraction of ChF, 64.1%; p = 0.02, and of EaF, 73.5%; p = 0.04 of KD, while the reduction in contraction of BF was 63.1%; p = 0.06. In conclusion, fractions of green and crimson Yemeni khat leaves contracted aortas of Lewis rats. Both leaves behave almost similarly. Contraction induced by chloroform fraction produced alpha-sympathetic activity.

Phantom pain after eye amputation

DEFF Research Database (Denmark)

Rasmussen, Marie L R; Prause, Jan U; Toft, Peter B

2011-01-01

Purpose: To characterize the quality of phantom pain, its intensity and frequency following eye amputation. Possible triggers and relievers of phantom pain are investigated. Methods: The hospital database was searched using surgery codes for patients who received ocular evisceration, enucleation...... was conducted by a trained interviewer. Results: Of the 173 patients in the study, 39 experienced phantom pain. The median age of patients who had experienced phantom pain was 45 years (range: 19–88). Follow-up time from eye amputation to participation in the investigation was 4 years (range: 2–46). Phantom...... scale, ranging from 0 to 100, was 36 (range: 1–89). One-third of the patients experienced phantom pain every day. Chilliness, windy weather and psychological stress/fatigue were the most commonly reported triggers for pain. Conclusions: Phantom pain after eye amputation is relatively common. The pain...

Hybrid pregnant reference phantom series based on adult female ICRP reference phantom

Science.gov (United States)

Rafat-Motavalli, Laleh; Miri-Hakimabad, Hashem; Hoseinian-Azghadi, Elie

2018-03-01

This paper presents boundary representation (BREP) models of pregnant female and her fetus at the end of each trimester. The International Commission on Radiological Protection (ICRP) female reference voxel phantom was used as a base template in development process of the pregnant hybrid phantom series. The differences in shape and location of the displaced maternal organs caused by enlarging uterus were also taken into account. The CT and MR images of fetus specimens and pregnant patients of various ages were used to replace the maternal abdominal pelvic organs of template phantom and insert the fetus inside the gravid uterus. Each fetal model contains 21 different organs and tissues. The skeletal model of the fetus also includes age-dependent cartilaginous and ossified skeletal components. The replaced maternal organ models were converted to NURBS surfaces and then modified to conform to reference values of ICRP Publication 89. The particular feature of current series compared to the previously developed pregnant phantoms is being constructed upon the basis of ICRP reference phantom. The maternal replaced organ models are NURBS surfaces. With this great potential, they might have the feasibility of being converted to high quality polygon mesh phantoms.

Low Density Lipoprotein and Non-Newtonian Oscillating Flow Biomechanical Parameters for Normal Human Aorta.

Science.gov (United States)

Soulis, Johannes V; Fytanidis, Dimitrios K; Lampri, Olga P; Giannoglou, George D

2016-04-01

The temporal variation of the hemodynamic mechanical parameters during cardiac pulse wave is considered as an important atherogenic factor. Applying non-Newtonian blood molecular viscosity simulation is crucial for hemodynamic analysis. Understanding low density lipoprotein (LDL) distribution in relation to flow parameters will possibly spot the prone to atherosclerosis aorta regions. The biomechanical parameters tested were averaged wall shear stress (AWSS), oscillatory shear index (OSI) and relative residence time (RRT) in relation to the LDL concentration. Four non-Newtonian molecular viscosity models and the Newtonian one were tested for the normal human aorta under oscillating flow. The analysis was performed via computational fluid dynamic. Tested viscosity blood flow models for the biomechanical parameters yield a consistent aorta pattern. High OSI and low AWSS develop at the concave aorta regions. This is most noticeable in downstream flow region of the left subclavian artery and at concave ascending aorta. Concave aorta regions exhibit high RRT and elevated LDL. For the concave aorta site, the peak LDL value is 35.0% higher than its entrance value. For the convex site, it is 18.0%. High LDL endothelium regions located at the aorta concave site are well predicted with high RRT. We are in favor of using the non-Newtonian power law model for analysis. It satisfactorily approximates the molecular viscosity, WSS, OSI, RRT and LDL distribution. Concave regions are mostly prone to atherosclerosis. The flow biomechanical factor RRT is a relatively useful tool for identifying the localization of the atheromatic plaques of the normal human aorta.

CD45lowc-Kithigh cells have hematopoietic properties in the mouse aorta-gonad-mesonephros region

International Nuclear Information System (INIS)

Nobuhisa, Ikuo; Yamasaki, Shoutarou; Ramadan, Ahmed; Taga, Tetsuya

2012-01-01

Long-term reconstituting hematopoietic stem cells first arise from the aorta of the aorta-gonad-mesonephros (AGM) region in a mouse embryo. We have previously reported that in cultures of the dispersed AGM region, CD45 low c-Kit + cells possess the ability to reconstitute multilineage hematopoietic cells, but investigations are needed to show that this is not a cultured artifact and to clarify when and how this population is present. Based on the expression profile of CD45 and c-Kit in freshly dissociated AGM cells from embryonic day 9.5 (E9.5) to E12.5 and aorta cells in the AGM from E13.5 to E15.5, we defined six cell populations (CD45 − c-Kit − , CD45 − c-Kit low , CD45 − c-Kit high , CD45 low c-Kit high , CD45 high c-Kit high , and CD45 high c-Kit very low ). Among these six populations, CD45 low c-Kit high cells were most able to form hematopoietic cell colonies, but their ability decreased after E11.5 and was undetectable at E13.5 and later. The CD45 low c-Kit high cells showed multipotency in vitro. We demonstrated further enrichment of hematopoietic activity in the Hoechst dye-effluxing side population among the CD45 low c-Kit high cells. Here, we determined that CD45 low c-Kit high cells arise from the lateral plate mesoderm using embryonic stem cell-derived differentiation system. In conclusion, CD45 low c-Kit high cells are the major hematopoietic cells of mouse AGM.

Aortocaval fistula: an infrequent complication of aneurysm of the abdominal aorta; Fistula aortocava: complicacion infrecuente tras rotura de aneurisma de aorta abdominal

Energy Technology Data Exchange (ETDEWEB)

Alpera, R.; Ardoy, F.; Gallego, J. A.

2002-07-01

A case is reported of aortocaval fistula (ACF) as an infrequent complication of an aneurysm of the abdominal aorta (AAA) that debuted clinically with pain in the right lumbar fossa and kidney failure. the diagnosis was made by helicoid computed tomography (HCT) and confirmed surgery. HCT findings consisted of an early accentuation of the inferior vena cava (ICV) in the arterial phase, and visualization of the communication between the aorta and inferior vena cava. (Author) 8 refs.

Heterogeneity of smooth muscle cells in tunica media of aorta in ...

African Journals Online (AJOL)

... of the tunica media of goat aorta are phenotypically heterogeneous and run in multiple directions. These characteristics probably confer mechanical strength and functional plasticity to the aortic wall. Designers of aortic substitutes should bear this in mind. Keywords: Vascular, Smooth Muscle Cells, Heterogeneity, Aorta ...

Development of realistic physical breast phantoms matched to virtual breast phantoms based on human subject data

International Nuclear Information System (INIS)

Kiarashi, Nooshin; Nolte, Adam C.; Sturgeon, Gregory M.; Ghate, Sujata V.; Segars, William P.; Nolte, Loren W.; Samei, Ehsan

2015-01-01

Purpose: Physical phantoms are essential for the development, optimization, and evaluation of x-ray breast imaging systems. Recognizing the major effect of anatomy on image quality and clinical performance, such phantoms should ideally reflect the three-dimensional structure of the human breast. Currently, there is no commercially available three-dimensional physical breast phantom that is anthropomorphic. The authors present the development of a new suite of physical breast phantoms based on human data. Methods: The phantoms were designed to match the extended cardiac-torso virtual breast phantoms that were based on dedicated breast computed tomography images of human subjects. The phantoms were fabricated by high-resolution multimaterial additive manufacturing (3D printing) technology. The glandular equivalency of the photopolymer materials was measured relative to breast tissue-equivalent plastic materials. Based on the current state-of-the-art in the technology and available materials, two variations were fabricated. The first was a dual-material phantom, the Doublet. Fibroglandular tissue and skin were represented by the most radiographically dense material available; adipose tissue was represented by the least radiographically dense material. The second variation, the Singlet, was fabricated with a single material to represent fibroglandular tissue and skin. It was subsequently filled with adipose-equivalent materials including oil, beeswax, and permanent urethane-based polymer. Simulated microcalcification clusters were further included in the phantoms via crushed eggshells. The phantoms were imaged and characterized visually and quantitatively. Results: The mammographic projections and tomosynthesis reconstructed images of the fabricated phantoms yielded realistic breast background. The mammograms of the phantoms demonstrated close correlation with simulated mammographic projection images of the corresponding virtual phantoms. Furthermore, power

Development of realistic physical breast phantoms matched to virtual breast phantoms based on human subject data

Energy Technology Data Exchange (ETDEWEB)

Kiarashi, Nooshin [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 and Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Nolte, Adam C. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Sturgeon, Gregory M.; Ghate, Sujata V. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Segars, William P. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 and Medical Physics Graduate Program, Duke University, Durham, North Carolina 27708 (United States); Nolte, Loren W. [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Samei, Ehsan [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27708 (United States); Department of Physics, Duke University, Durham, North Carolina 27708 (United States); and others

2015-07-15

Purpose: Physical phantoms are essential for the development, optimization, and evaluation of x-ray breast imaging systems. Recognizing the major effect of anatomy on image quality and clinical performance, such phantoms should ideally reflect the three-dimensional structure of the human breast. Currently, there is no commercially available three-dimensional physical breast phantom that is anthropomorphic. The authors present the development of a new suite of physical breast phantoms based on human data. Methods: The phantoms were designed to match the extended cardiac-torso virtual breast phantoms that were based on dedicated breast computed tomography images of human subjects. The phantoms were fabricated by high-resolution multimaterial additive manufacturing (3D printing) technology. The glandular equivalency of the photopolymer materials was measured relative to breast tissue-equivalent plastic materials. Based on the current state-of-the-art in the technology and available materials, two variations were fabricated. The first was a dual-material phantom, the Doublet. Fibroglandular tissue and skin were represented by the most radiographically dense material available; adipose tissue was represented by the least radiographically dense material. The second variation, the Singlet, was fabricated with a single material to represent fibroglandular tissue and skin. It was subsequently filled with adipose-equivalent materials including oil, beeswax, and permanent urethane-based polymer. Simulated microcalcification clusters were further included in the phantoms via crushed eggshells. The phantoms were imaged and characterized visually and quantitatively. Results: The mammographic projections and tomosynthesis reconstructed images of the fabricated phantoms yielded realistic breast background. The mammograms of the phantoms demonstrated close correlation with simulated mammographic projection images of the corresponding virtual phantoms. Furthermore, power

Feasibility of low contrast media volume in CT angiography of the aorta

International Nuclear Information System (INIS)

Seehofnerová, Anna; Kok, Madeleine; Mihl, Casper; Douwes, Dave; Sailer, Anni; Nijssen, Estelle; Haan, Michiel J.W. de; Wildberger, Joachim E.; Das, Marco

2015-01-01

Using smaller volumes of contrast media (CM) in CT angiography (CTA) is desirable in terms of cost reduction and prevention of contrast-induced nephropathy (CIN). The purpose was to evaluate the feasibility of low CM volume in CTA of the aorta. 77 patients referred for CTA of the aorta were scanned using a standard MDCT protocol at 100 kV. A bolus of 50 ml CM (Iopromide 300 mg Iodine/ml) at a flow rate of 6 ml/s was applied (Iodine delivery rate IDR = 1.8 g/s; Iodine load 15 g) followed by a saline bolus of 40 ml at the same flow rate. Scan delay was determined by the test bolus method. Subjective image quality was assessed and contrast enhancement was measured at 10 anatomical levels of the aorta. Diagnostic quality images were obtained for all patients, reaching a mean overall contrast enhancement of 324 ± 28 HU. Mean attenuation was 350 ± 60 HU at the thoracic aorta and 315 ± 83 HU at the abdominal aorta. A straightforward low volume CM protocol proved to be technically feasible and led to CTA examinations reaching diagnostic image quality of the aorta at 100 kV. Based on these findings, the use of a relatively small CM bolus can be incorporated into routine clinical imaging

Calcified aneurysm of the abdominal aorta 12 years after umbilical artery catheterization

Energy Technology Data Exchange (ETDEWEB)

Blondiaux, Eleonore; Miquel, Julie [Rouen University Hospital Charles Nicolle, Department of Radiology, Rouen (France); Thomas, Pascale; Watelet, Jacques [Rouen University Hospital Charles Nicolle, Department of Vascular Surgery, Rouen (France); Laloum, Denis [Caen University Hospital, Pediatric Intensive Care Unit, Department of Neonatal Medicine, Caen (France); Dacher, Jean-Nicolas [Rouen University Hospital Charles Nicolle, Department of Radiology, Rouen (France); UFR Medecine et Pharmacie, Laboratoire Quant-If, Rouen Cedex 01 (France)

2008-02-15

We report a 12-year-old boy who presented with abdominal pain and who was found to have an aneurysm of the abdominal aorta (AAA). The patient was born from a quadruplet pregnancy induced by in vitro fertilization. Postnatal transient respiratory distress required assisted ventilation that had been monitored by two consecutive umbilical arterial catheters (UAC). AAA is a rare condition in childhood. Infection and/or trauma are known to be the most frequent causes. Most of the reported cases have occurred in children in whom a UAC had been placed during the neonatal period. In this patient the delay between UAC placement and diagnosis was considerable. At the time of this report the patient had remained well during a follow-up of 8 years after treatment. (orig.)

Calcified aneurysm of the abdominal aorta 12 years after umbilical artery catheterization

International Nuclear Information System (INIS)

Blondiaux, Eleonore; Miquel, Julie; Thomas, Pascale; Watelet, Jacques; Laloum, Denis; Dacher, Jean-Nicolas

2008-01-01

We report a 12-year-old boy who presented with abdominal pain and who was found to have an aneurysm of the abdominal aorta (AAA). The patient was born from a quadruplet pregnancy induced by in vitro fertilization. Postnatal transient respiratory distress required assisted ventilation that had been monitored by two consecutive umbilical arterial catheters (UAC). AAA is a rare condition in childhood. Infection and/or trauma are known to be the most frequent causes. Most of the reported cases have occurred in children in whom a UAC had been placed during the neonatal period. In this patient the delay between UAC placement and diagnosis was considerable. At the time of this report the patient had remained well during a follow-up of 8 years after treatment. (orig.)

NMR-CT image and symbol phantoms

International Nuclear Information System (INIS)

Hongo, Syozo; Yamaguchi, Hiroshi; Takeshita, Hiroshi

1990-01-01

We have developed Japanese phantoms in two procedures. One is described as a mathematical expression. Another is 'symbol phantoms' in 3 dimensional picture-elements, each of which symbolize an organ name. The concept and the algorithm of the symbol phantom enables us to make a phantom for a individual in terms of all his transversal section images. We got 85 transversal section images of head and trunk parts, and those of 40 legs parts by using NMR-CT. We have made the individual phantom for computation of organ doses. The transversal section images were not so clear to identify all organs needed to dose estimation that we had to do hand-editing the shapes of organs with viewing a typical section images: we could not yet make symbol phantom in a automatic editing. Symbols were coded to be visual cords as ASCII characters. After we got the symbol phantom of the first stage, we can edit it easily using a word-processor. Symbol phantom could describe more freely the shape of organs than mathematical phantom. Symbol phantom has several advantages to be an individual phantom, but the only difficult point is how to determine its end-point as a reference man when we apply the method to build the reference man. (author)

Device occlusion of pseudoaneurysm of ascending aorta

International Nuclear Information System (INIS)

Agarwal, Mridul; Ray, Mili; Pallavi, M; Sen, Supratim; Ganguly, Debosree; Joshi, Pankaj; Tanti, Sanjay; Chattopadhyay, Amitabh; Bandyopadhyay, Biswajit

2011-01-01

Pseudoaneurysm of ascending aorta is an infrequent but well-recognized and potentially fatal complication after cardiac surgeries. The complication can develop early, delayed or late, and the presentation is also varied. We are presenting here two cases of pseudoaneurysm of ascending aorta following cardiac surgery that were successfully managed by the transcatheter method. The first one occurred following coronary artery bypass surgery and the second one occurred following double-valve replacement surgery. The aortic openings of these aneurysms were occluded with 12 mm and 10 mm atrial septal occluders, respectively, with a good outcome. An immediate postprocedure angiogram showed no residual flow into the sac. Six months of follow-up of both cases also showed excellent results

Construction of Chinese reference female phantom

International Nuclear Information System (INIS)

Sheng Yinxiangzi; Liu Lixing; Xia Xiaobin

2013-01-01

In this study, a Voxel-based Chinese Reference female Phantom (VCRP-woman) is developed from an individual female phantom which was based on high resolution cross-sectional color photographs. An in-house C ++ program was developed to adjust the phantom. Finally, a reference female phantom with have the same height, weighte and similar organs masses with the Chinese reference adult female data. The adjusted phantom is then imported to MCNPX to calculate the organs absorbed dose and effective dose conversion coefficients. Results are compared between VCRP-woman and the ICRP adult reference female phantom. (authors)

Phantom Sensations, Supernumerary Phantom Limbs and Apotemnophilia: Three Body Representation Disorders.

Science.gov (United States)

Tatu, Laurent; Bogousslavsky, Julien

2018-01-01

Body representation disorders continue to be mysterious and involve the anatomical substrate that underlies the mental representation of the body. These disorders sit on the boundaries of neurological and psychiatric diseases. We present the main characteristics of 3 examples of body representation disorders: phantom sensations, supernumerary phantom limb, and apotemnophilia. The dysfunction of anatomical circuits that regulate body representation can sometimes have paradoxical features. In the case of phantom sensations, the patient feels the painful subjective sensation of the existence of the lost part of the body after amputation, surgery or trauma. In case of apotemnophilia, now named body integrity identity disorder, the subject wishes for the disappearance of the existing and normal limb, which can occasionally lead to self-amputation. More rarely, a brain-damaged patient with 4 existing limbs can report the existence of a supernumerary phantom limb. © 2018 S. Karger AG, Basel.

21. Phantom pain.

NARCIS (Netherlands)

Wolff, A.P.; Vanduynhoven, E.; Kleef, M. van; Huygen, F.; Pope, J.E.; Mekhail, N.

2011-01-01

Phantom pain is pain caused by elimination or interruption of sensory nerve impulses by destroying or injuring the sensory nerve fibers after amputation or deafferentation. The reported incidence of phantom limb pain after trauma, injury or peripheral vascular diseases is 60% to 80%. Over half the

Dietary fat level affecting histochemical radiosensitivity in dorsal aorta in rats

International Nuclear Information System (INIS)

Yousri, R.M.; Roushdy, H.M.; EL-Malkh, N.M.; Ashry, M.A.; Soliman, S.M.

1988-01-01

The present work has been conducted to investigate the effect of dietary fat status and/or cumulative whole body gamma radiation exposures up to 15 Gy the histochemical pattern of the dorsal aortas of male albino rats. Experimental animals were fed on either fat-rich or fat-free diet and the observations compared with those fed normal fat diet. The histochemical investigations has been confined to the concentration levels of mucopolysaccharide substance and total lipids. The dorsal aorta normal fat group showed higher content of PAS-positive material in the first two layers of the aorta wall in comparison with decreased amount of collagen fibers was shown in fat-rich group

Evaluation of the Vasoplegic impact of Papaverine in the rat aorta

International Nuclear Information System (INIS)

Yavuz, C.; Callskan, A.; Karahan, O.; Demirtas, S.; Yazici, S.; Guclu, O.; Mavitas, B.; Donmez, S.; Peker, R. O.; Yildirim, Y.; Gokalp, O.

2014-01-01

Objective: To identify the degree of vasoplegic affinity of papaverine to rat thoracic aortas following constriction caused by adrenalin, serotonin and potassium chloride in an in-vitro model. Methods: The in vitro vasoplegic efficacy of papaverine against adrenalin (10-5 M), serotonin (5HT) (10-4 M), and KCl (60 mM) was assessed, using a rat aortic vasospasm model in an organ bath. First, aortic rings were constricted with a submaximal dose of vasoconstrictor agents. The samples were then incubated with papaverine (3x10-4 M) for 20 minutes, followed by readministration of the same vasoconstrictor agents. The first vasospastic response (before papaverine incubation) and the new vasoconstrictor responses (after papaverine incubation) of the vessels were then compared. Results: The vasoplegic effect of vasoconstrictor agents in decreasing order was observed as adrenalin>KCl>5HT. This different affinity for the vasoplegic effect is considered to be a temporary impact of the drugs and the maximal inhibition of vasoconstriction was detected for the adrenalin receptor. Conclusion: The relevance of the macromolecules is responsible for the permanent efficacy of the drugs. Different degrees of vasoconstriction were also obtained after papaverine administration, which suggests that different responses can occur as a result of different stimulation of receptor modulators. (author)

Characterization of atherosclerotic disease in thoracic aorta: A 3D, multicontrast vessel wall imaging study

Energy Technology Data Exchange (ETDEWEB)

Zhou, Changwu [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Department of Radiology, The Second Clinical Medical College, Yangzhou University, Yangzhou (China); Qiao, Huiyu; He, Le [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Yuan, Chun [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Department of Radiology, University of Washington, Seattle, WA (United States); Chen, Huijun; Zhang, Qiang; Li, Rui [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China); Wang, Wei; Du, Fang [Department of Radiology, The Second Clinical Medical College, Yangzhou University, Yangzhou (China); Li, Cheng, E-mail: cjr.licheng@vip.163.com [Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing (China); Zhao, Xihai, E-mail: xihaizhao@tsinghua.edu.cn [Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing (China)

2016-11-15

Purpose: To investigate the characteristics of plaque in the thoracic aorta using three dimensional multicontrast magnetic resonance imaging. Materials and methods: Elderly subjects (≥60 years) were recruited in this study. Thoracic aorta was imaged on a 3.0T MR scanner by acquiring multicontrast sequences. The plaque burden was evaluated by measuring lumen area, wall area, wall thickness, and normalized wall index. The presence or absence of plaque and intraplaque hemorrhage (IPH)/mural thrombus (MT) were identified. The characteristics of atherosclerosis among different thoracic aorta segments (AAO: ascending aorta; AOA: aortic arch, and DOA: descending aorta) were determined. Results: Of 66 recruited subjects (mean age 72.3 ± 6.2 years, 30 males), 55 (83.3%) had plaques in the thoracic aorta. The prevalence of plaque in AAO, AOA, and DAO was 5.4%, 72.7%, and 71.2%, respectively. In addition, 21.2% of subjects were found to have lesions with IPH/MT in the thoracic aorta. The prevalence of IPH/MT in segment of AAO, AOA and DAO was 0%, 13.6%, and 12.1%, respectively. The aortic wall showed the highest NWI in DAO (34.1% ± 4.8%), followed by AOA (31.2% ± 5%), and AAO (26.8% ± 3.3%) (p < 0.001). Conclusion: Three dimensional multicontrast MR imaging is capable of characterizing atherosclerotic plaques in the thoracic aorta. The findings of high prevalence of plaques and the presence of high risk plaques in the thoracic aorta suggest early screening for aortic vulnerable lesions in the elderly.

Characterization of atherosclerotic disease in thoracic aorta: A 3D, multicontrast vessel wall imaging study

International Nuclear Information System (INIS)

Zhou, Changwu; Qiao, Huiyu; He, Le; Yuan, Chun; Chen, Huijun; Zhang, Qiang; Li, Rui; Wang, Wei; Du, Fang; Li, Cheng; Zhao, Xihai

2016-01-01

Purpose: To investigate the characteristics of plaque in the thoracic aorta using three dimensional multicontrast magnetic resonance imaging. Materials and methods: Elderly subjects (≥60 years) were recruited in this study. Thoracic aorta was imaged on a 3.0T MR scanner by acquiring multicontrast sequences. The plaque burden was evaluated by measuring lumen area, wall area, wall thickness, and normalized wall index. The presence or absence of plaque and intraplaque hemorrhage (IPH)/mural thrombus (MT) were identified. The characteristics of atherosclerosis among different thoracic aorta segments (AAO: ascending aorta; AOA: aortic arch, and DOA: descending aorta) were determined. Results: Of 66 recruited subjects (mean age 72.3 ± 6.2 years, 30 males), 55 (83.3%) had plaques in the thoracic aorta. The prevalence of plaque in AAO, AOA, and DAO was 5.4%, 72.7%, and 71.2%, respectively. In addition, 21.2% of subjects were found to have lesions with IPH/MT in the thoracic aorta. The prevalence of IPH/MT in segment of AAO, AOA and DAO was 0%, 13.6%, and 12.1%, respectively. The aortic wall showed the highest NWI in DAO (34.1% ± 4.8%), followed by AOA (31.2% ± 5%), and AAO (26.8% ± 3.3%) (p < 0.001). Conclusion: Three dimensional multicontrast MR imaging is capable of characterizing atherosclerotic plaques in the thoracic aorta. The findings of high prevalence of plaques and the presence of high risk plaques in the thoracic aorta suggest early screening for aortic vulnerable lesions in the elderly.

Evaluation of the normal thoracic and abdominal aorta diameters by computerized tomography; Avaliacao dos diametros normais da aorta toracica e abdominal pela tomografia computadorizada

Energy Technology Data Exchange (ETDEWEB)

Lucarelli, Claudio Luiz

1995-07-01

The study was undertaken to evaluate, through computerized tomography, the diameters of the normal thoracic and abdominal aorta, as well as they are connected to gender, age and body surface area; and the ratio between measurements obtained at the ascending and descending limbs of the thoracic aorta, and between the abdominal aortic diameters. For that reason, we measured the widest anteroposterior diameters of the thoracic aortas at the levels of the arch, the root, the pulmonary artery, and the thoracic-abdominal transition, as well as the level of the emergence of the superior mesenteric artery, of the renal hila and just cephalad to the bifurcation of the abdominal aortas of 350 patients without cardiovascular diseases who had undergone computerized tomography of the thorax and/or abdomen for any other reasons. Observation and statistic analyses led us to conclude that: 1) both the thoracic and abdominal aortic diameters are reduced from their proximal to their distal portions; 2) the body surface influences the size of the aorta, although only extreme variations alter the vessel's caliber; 3) vessel diameter was observed to gradually increase with age; 4) men were found to have larger diameters than age matched women; 5) the ratio between the ascending and descending aortic diameters varies according to gender and age; 6) the relations between abdominal aortic diameters measured at the level of renal hila and cephalad to the bifurcation are independent from gender and age. But the relation between those measured at the level of the superior mesenteric artery and cephalad to the bifurcation are linked to gender, but not to age. (author)

Evaluation of the normal thoracic and abdominal aorta diameters by computerized tomography; Avaliacao dos diametros normais da aorta toracica e abdominal pela tomografia computadorizada

Energy Technology Data Exchange (ETDEWEB)

Lucarelli, Claudio Luiz

1995-07-01

The study was undertaken to evaluate, through computerized tomography, the diameters of the normal thoracic and abdominal aorta, as well as they are connected to gender, age and body surface area; and the ratio between measurements obtained at the ascending and descending limbs of the thoracic aorta, and between the abdominal aortic diameters. For that reason, we measured the widest anteroposterior diameters of the thoracic aortas at the levels of the arch, the root, the pulmonary artery, and the thoracic-abdominal transition, as well as the level of the emergence of the superior mesenteric artery, of the renal hila and just cephalad to the bifurcation of the abdominal aortas of 350 patients without cardiovascular diseases who had undergone computerized tomography of the thorax and/or abdomen for any other reasons. Observation and statistic analyses led us to conclude that: 1) both the thoracic and abdominal aortic diameters are reduced from their proximal to their distal portions; 2) the body surface influences the size of the aorta, although only extreme variations alter the vessel's caliber; 3) vessel diameter was observed to gradually increase with age; 4) men were found to have larger diameters than age matched women; 5) the ratio between the ascending and descending aortic diameters varies according to gender and age; 6) the relations between abdominal aortic diameters measured at the level of renal hila and cephalad to the bifurcation are independent from gender and age. But the relation between those measured at the level of the superior mesenteric artery and cephalad to the bifurcation are linked to gender, but not to age. (author)

[Coarctation of the descending aorta. A rare form of connatal aortic stenosis].

Science.gov (United States)

Stammwitz, E; Schöttler, M; Brix, F; Poser, H L; Langkau, G; Yükseltan, I

1983-07-01

A clinical diagnosis of a coarctation of the aorta was made in a 17-year-old female hypertensive patient. Angiography revealed an atypical stenosis of the descending aorta which was surgically corrected. The causes of aortic stenoses are discussed.

Differential effects of isoproterenol on the activity of angiotensin-converting enzyme in the rat heart and aorta

Directory of Open Access Journals (Sweden)

Busatto V.C.W.

1999-01-01

Full Text Available The excessive stimulation of beta-adrenergic receptors in the heart induces myocardial hypertrophy. There are several experimental data suggesting that this hypertrophy may also depend, at least partially, on the increase of local production of angiotensin II secondary to the activation of the cardiac renin-angiotensin system. In this study we investigated the effects of isoproterenol on the activity of angiotensin-converting enzyme (ACE in the heart and also in the aorta and plasma. Male Wistar rats weighing 250 to 305 g were treated with a dose of (±-isoproterenol (0.3 mg kg-1 day-1, N = 8 sufficient to produce cardiac hypertrophy without deleterious effects on the pumping capacity of the heart. Control rats (N = 7 were treated with vehicle (corn oil. The animals were killed one week later. ACE activity was determined in vitro in the four cardiac chambers, aorta and plasma by a fluorimetric assay. A significant hypertrophy was observed in both ventricular chambers. ACE activity in the atria remained constant after isoproterenol treatment. There was a significant increase (P<0.05 of ACE activity in the right ventricle (6.9 ± 0.9 to 8.2 ± 0.6 nmol His-Leu g-1 min-1 and in the left ventricle (6.4 ± 1.1 to 8.9 ± 0.8 nmol His-Leu g-1 min-1. In the aorta, however, ACE activity decreased (P<0.01 after isoproterenol (41 ± 3 to 27 ± 2 nmol His-Leu g-1 min-1 while it remained unchanged in the plasma. These data suggest that ACE expression in the heart can be increased by stimulation of beta-adrenoceptors. However, this effect is not observed on other local renin-angiotensin systems, such as the aorta. Our data also suggest that the increased sympathetic discharge and the elevated plasma concentration of catecholamines may contribute to the upregulation of ACE expression in the heart after myocardial infarction and heart failure.

Assessment of the accuracy of AortaScan for detection of abdominal aortic aneurysm (AAA).

Science.gov (United States)

Abbas, A; Smith, A; Cecelja, M; Waltham, M

2012-02-01

AortaScan AMI 9700 is a portable 3D ultrasound device that automatically measures the maximum diameter of the abdominal aorta without the need for a trained sonographer. It is designed to rapidly diagnose or exclude an AAA and may have particular use in screening programs. Our objective was to determine its accuracy to detect AAA. Subjects from our AAA screening and surveillance programs were examined. The aorta was scanned using the AortaScan and computed tomography (CT). Ninety-one subjects underwent imaging (44 AAA on conventional ultrasound surveillance and 47 controls). The largest measurement obtained by AortaScan was compared against the CT-aortic measurement. The mean aortic diameter was 2.8 cm. The CT scan confirmed the diagnosis of AAA in 43 subjects. There was one false positive measurement on conventional ultrasound. AortaScan missed the diagnosis of AAA in eight subjects. There were thirteen false positive measurements. The sensitivity, specificity, positive and negative predictive values were 81%, 72%, 72% and 81% respectively. A device to detect AAA without the need for a trained operator would have potential in a community-based screening programme. The AortaScan, however, lacks adequate sensitivity and significant technical improvement is necessary before it could be considered a replacement for trained screening personnel. Copyright © 2011 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Evaluation of reconstruction parameters of electrical impedance tomography on aorta detection during saline bolus injection

Directory of Open Access Journals (Sweden)

Thürk Florian

2016-09-01

Full Text Available An accurate detection of anatomical structures in electrical impedance tomography (EIT is still at an early stage. Aorta detection in EIT is of special interest, since it would favor non-invasive assessment of hemodynamic processes in the body. Here, diverse EIT reconstruction parameters of the GREIT algorithm were systematically evaluated to detect the aorta after saline bolus injection in apnea. True aorta position and size were taken from computed tomography (CT. A comparison with CT showed that the smallest error for aorta displacement was attained for noise figure nf = 0.7, weighting radius rw = 0.15, and target size ts = 0.01. The spatial extension of the aorta was most precise for nf = 0.7, rw = 0.25, and ts = 0.07. Detection accuracy (F1-score was highest with nf = 0.6, rw = 0.15, and ts = 0.04. This work provides algorithm-related evidence for potentially accurate aorta detection in EIT after injection of a saline bolus.

Factors influencing the mechanical behaviour of healthy human descending thoracic aorta

International Nuclear Information System (INIS)

Guinea, Gustavo V; Atienza, José M; Rojo, Francisco J; Yiqun, Li; Claes, Els; Elices, Manuel; García-Herrera, Claudio M; Goicolea, José M; García-Montero, Carlos; Burgos, Raúl L; Goicolea, Francisco J

2010-01-01

In recent times, significant effort has been made to understand the mechanical behaviour of the arterial wall and how it is affected by the different vascular pathologies. However, to be able to interpret the results correctly, it is essential that the influence of other factors, such as aging or anisotropy, be understood. Knowledge of mechanical behaviour of the aorta has been customarily constrained by lack of data on fresh aortic tissue, especially from healthy young individuals. In addition, information regarding the point of rupture is also very limited. In this study, the mechanical behaviour of the descending thoracic aorta of 28 organ donors with no apparent disease, whose ages vary from 17 to 60 years, is evaluated. Tensile tests up to rupture are carried out to evaluate the influence of age and wall anisotropy. Results reveal that the tensile strength and stretch at failure of healthy descending aortas show a significant reduction with age, falling abruptly beyond the age of 30. This fact places age as a key factor when mechanical properties of descending aorta are considered

The value of anterior displacement of the abdominal aorta in diagnosing neuroblastoma in children

Energy Technology Data Exchange (ETDEWEB)

Schiavon, Jose Luiz de Oliveira; Caran, Eliana Maria Monteiro; Lederman, Henrique Manoel, E-mail: schiavon00@gmail.com [Universidade Federal de Sao Paulo (EPM/UNIFESP), Sao Paulo, SP (Brazil). Escola Paulista de Medicina; Odone Filho, Vicente [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina

2016-11-15

Objective: To determine the value of anterior displacement of the abdominal aorta, when present at any level or only at the level of the adrenal gland, contralateral to the mass, in diagnosing neuroblastoma on computed tomography or magnetic resonance imaging in children up to 7 years of age. Materials and Methods: Imaging examinations of 66 patients were classified by consensus as for the presence of anterior aorta displacement and were compared with the pathology report. Results: We found anterior abdominal aorta displacement in 26 (39.39%) of the 66 patients evaluated. Among those 26 patients, we identified neuroblastoma in 22 (84.62%), nephroblastoma in 3 (11.54%), and Burkitt lymphoma in 1 (3.85%). The positive predictive value was 84.62%, and the specificity was 88.24%. The displacement of the aorta was at the adrenal level, contralateral to the mass, in 14 cases, all of which were attributed to neuroblastoma. Conclusion: When the abdominal aorta is displaced at the level of the adrenal gland, contralateral to the mass, it can be said that the diagnosis is neuroblastoma, whereas abdominal aorta displacement occurring at other abdominal levels has a positive predictive value for neuroblastoma of approximately 85%. (author)

The value of anterior displacement of the abdominal aorta in diagnosing neuroblastoma in children

International Nuclear Information System (INIS)

Schiavon, Jose Luiz de Oliveira; Caran, Eliana Maria Monteiro; Lederman, Henrique Manoel; Odone Filho, Vicente

2016-01-01

Objective: To determine the value of anterior displacement of the abdominal aorta, when present at any level or only at the level of the adrenal gland, contralateral to the mass, in diagnosing neuroblastoma on computed tomography or magnetic resonance imaging in children up to 7 years of age. Materials and Methods: Imaging examinations of 66 patients were classified by consensus as for the presence of anterior aorta displacement and were compared with the pathology report. Results: We found anterior abdominal aorta displacement in 26 (39.39%) of the 66 patients evaluated. Among those 26 patients, we identified neuroblastoma in 22 (84.62%), nephroblastoma in 3 (11.54%), and Burkitt lymphoma in 1 (3.85%). The positive predictive value was 84.62%, and the specificity was 88.24%. The displacement of the aorta was at the adrenal level, contralateral to the mass, in 14 cases, all of which were attributed to neuroblastoma. Conclusion: When the abdominal aorta is displaced at the level of the adrenal gland, contralateral to the mass, it can be said that the diagnosis is neuroblastoma, whereas abdominal aorta displacement occurring at other abdominal levels has a positive predictive value for neuroblastoma of approximately 85%. (author)

Lipid Emulsion Inhibits Vasodilation Induced by a Toxic Dose of Bupivacaine via Attenuated Dephosphorylation of Myosin Phosphatase Target Subunit 1 in Isolated Rat Aorta

Science.gov (United States)

Ok, Seong-Ho; Byon, Hyo-Jin; Kwon, Seong-Chun; Park, Jungchul; Lee, Youngju; Hwang, Yeran; Baik, Jiseok; Choi, Mun-Jeoung; Sohn, Ju-Tae

2015-01-01

Lipid emulsions are widely used for the treatment of systemic toxicity that arises from local anesthetics. The goal of this in vitro study was to examine the cellular mechanism associated with the lipid emulsion-mediated attenuation of vasodilation induced by a toxic dose of bupivacaine in isolated endothelium-denuded rat aorta. The effects of lipid emulsion on vasodilation induced by bupivacaine, mepivacaine, and verapamil were assessed in isolated aorta precontracted with phenylephrine, the Rho kinase stimulant NaF, and the protein kinase C activator phorbol 12,13-dibutyrate (PDBu). The effects of Rho kinase inhibitor Y-27632 on contraction induced by phenylephrine or NaF were assessed. The effects of bupivacaine on intracellular calcium concentrations ([Ca2+]i) and tension induced by NaF were simultaneously measured. The effects of bupivacaine alone and lipid emulsion plus bupivacaine on myosin phosphatase target subunit 1 (MYPT1) phosphorylation induced by NaF were examined in rat aortic vascular smooth muscle cells. In precontracted aorta, the lipid emulsion attenuated bupivacaine-induced vasodilation but had no effect on mepivacaine-induced vasodilation. Y-27632 attenuated contraction induced by either phenylephrine or NaF. The lipid emulsion attenuated verapamil-induced vasodilation. Compared with phenylephrine-induced precontracted aorta, bupivacaine-induced vasodilation was slightly attenuated in NaF-induced precontracted aorta. The magnitude of the bupivacaine-induced vasodilation was higher than that of a bupivacaine-induced decrease in [Ca2+]i. Bupivacaine attenuated NaF-induced MYPT1 phosphorylation, whereas lipid emulsion pretreatment attenuated the bupivacaine-induced inhibition of MYPT1 phosphorylation induced by NaF. Taken together, these results suggest that lipid emulsions attenuate bupivacaine-induced vasodilation via the attenuation of inhibition of MYPT1 phosphorylation evoked by NaF. PMID:26664257

Development of an In Vitro PIV Setup for Preliminary Investigation of the Effects of Aortic Compliance on Flow Patterns and Hemodynamics.

Science.gov (United States)

Büsen, Martin; Arenz, Christian; Neidlin, Michael; Liao, Sam; Schmitz-Rode, Thomas; Steinseifer, Ulrich; Sonntag, Simon J

2017-09-01

The aorta with its compliance plays a major role in hemodynamics as it saves a portion of ejected blood during systole which is then released in diastole. The aortic compliance decreases with increasing age, which is related to several cardiovascular imparities and diseases. Changes in flow patterns and pressure curves, due to varying aortic compliance, are difficult to investigate in vivo. As a result, the aim of the present work was to develop an in vitro setup enabling standardized investigations on the effect of compliance changes on flow patterns and pressure curves. Therefore an experimental setup with an anatomically correct silicone phantom of the aortic arch was developed, suitable for optical flow measurements under pulsatile inflow conditions. The setup was developed for precise adjustments of different compliances and optical flow measurements. Particle image velocimetry measurements were carried out downstream of the aortic valve in the center plane perpendicular to the valve with compliance adjusted between 0.62 × 10 -3 to 1.82 × 10 -3  mmHg -1 . Preliminary results of the in vitro investigations showed that decreases in compliance results in significant increases in pressure changes with respect to time (dp/dt) and altered pressure curves in the aortic arch. In terms of flow, an increased aortic stiffness lead to higher mean velocities and decreased vortex development in the aortic sinuses. As in vivo validation and translation remains difficult, the results have to be considered as preliminary in vitro insights into the mechanisms of (age-related) compliance changes.

Obstructive pneumonia: an indication for surgery in mega aorta syndrome.

Science.gov (United States)

Kalkat, Maninder S; Bonser, Robert S

2003-04-01

A 76-year-old woman with annuloaortic ectasia, aortic regurgitation, and aneurysmal dilatation extending from the root to mid descending aorta presented with symptoms of bronchial compression and obstructive pneumonitis. Despite vigorous antibiotic treatment and physiotherapy, the pneumonitis persisted with clinical and radiologic deterioration. An emergency operation was performed to relieve bronchial compression. The operation comprised homograft aortic root replacement with prosthetic replacement of the arch and descending aorta. Postoperatively the pneumonia rapidly resolved.

Evolution of dosimetric phantoms

International Nuclear Information System (INIS)

Reddy, A.R.

2010-01-01

In this oration evolution of the dosimetric phantoms for radiation protection and for medical use is briefly reviewed. Some details of the development of Indian Reference Phantom for internal dose estimation are also presented

Preparing a voxel-simulator of Alderson Rando physical phantom

International Nuclear Information System (INIS)

Boia, Leonardo S.; Martins, Maximiano C.; Silva, Ademir X.; Salmon Junior, Helio A.; Soares, Alessandro F.N.S.

2011-01-01

There are, nowadays, sorts of anthropomorphycal phantoms which are used for simulation of radiation transport by the matter and also the deposition of energy in such radiation in human tissues and organs, because an in-vitro dosimetry becomes very either complicated or even impossible in some cases. In the present work we prepared a computational phantom in voxels based on computational tomography of Rando-Alderson. This phantom is one of the most known human body simulators on the scope of ionizing radiation dosimetry, and it is used for radioprotection issues and dosimetry from radiotherapy and brachytherapy treatments as well. The preparation of a voxel simulator starts with the image acquisition by a tomograph found at COI/RJ (Clinicas Oncologicas Integradas). The images were generated with 1mm cuts and collected for analysis. After that step the images were processed in SAPDI (Sistema Automatizado de Processamento Digital de Imagem) in order to amplify the images regions intending to facilitate the task in their segmentation. SAPDI is based on parameters described by Hounsfield scale. After that, it has begun discretization of elements in IDs voxels using Scan2MCNP software - which converts images to a sequential text file containing the voxels' IDs ready to be introduced into MCNPX input; however, this set can be turned to a voxel's IDs matrix and used in other Monte Carlo codes, such as Geant4, PENELOPE and EGSnrc. Finished this step, the simulator is able to simulate with accurate geometry the physical phantom. It's possible to study a large number of cases by computational techniques of geometry's insertions of tumors and TLDs, which makes this simulator a research material useful for a lot of subjects. (author)

Preparing a voxel-simulator of Alderson Rando physical phantom

Energy Technology Data Exchange (ETDEWEB)

Boia, Leonardo S.; Martins, Maximiano C.; Silva, Ademir X., E-mail: lboia@con.ufrj.br, E-mail: ademir@con.ufrj.br [Programa de Engenharia Nuclear (PEN/COPPE/UFRJ). Universidade Federal do Rio de Janeiro, RJ (Brazil); Salmon Junior, Helio A., E-mail: heliosalmon@coinet.com.br [COI - Clinicas Oncologicas Integradas, MD.X Barra Medical Center, Rio de Janeiro, RJ (Brazil); Soares, Alessandro F.N.S., E-mail: afacure@cnen.gov.br [Comissao Nacional de Engenharia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

2011-07-01

There are, nowadays, sorts of anthropomorphycal phantoms which are used for simulation of radiation transport by the matter and also the deposition of energy in such radiation in human tissues and organs, because an in-vitro dosimetry becomes very either complicated or even impossible in some cases. In the present work we prepared a computational phantom in voxels based on computational tomography of Rando-Alderson. This phantom is one of the most known human body simulators on the scope of ionizing radiation dosimetry, and it is used for radioprotection issues and dosimetry from radiotherapy and brachytherapy treatments as well. The preparation of a voxel simulator starts with the image acquisition by a tomograph found at COI/RJ (Clinicas Oncologicas Integradas). The images were generated with 1mm cuts and collected for analysis. After that step the images were processed in SAPDI (Sistema Automatizado de Processamento Digital de Imagem) in order to amplify the images regions intending to facilitate the task in their segmentation. SAPDI is based on parameters described by Hounsfield scale. After that, it has begun discretization of elements in IDs voxels using Scan2MCNP software - which converts images to a sequential text file containing the voxels' IDs ready to be introduced into MCNPX input; however, this set can be turned to a voxel's IDs matrix and used in other Monte Carlo codes, such as Geant4, PENELOPE and EGSnrc. Finished this step, the simulator is able to simulate with accurate geometry the physical phantom. It's possible to study a large number of cases by computational techniques of geometry's insertions of tumors and TLDs, which makes this simulator a research material useful for a lot of subjects. (author)

Ultra-sonografia da aorta abdominal e de seus ramos em cães Ultrasonography of abdominal aorta and its branches in dogs

Directory of Open Access Journals (Sweden)

Lilian Kamikawa

2007-04-01

Full Text Available O ultra-som bidimensional e o ultra-som Doppler foram utilizados para avaliar a biometria e a hemodinâmica da aorta abdominal e artérias ilíacas externas de 131cães clinicamente normais. Os resultados da avaliação biométrica da aorta abdominal indicaram um diâmetro médio de 0,80cm para o seu segmento diafragmático (AOD; 0,74cm para o seu segmento caudal às artérias renais (AOR e 0,69cm para o segmento cranial à sua bifurcação (AOT. A artéria ilíaca externa direita (AIED apresentou o diâmetro médio de 0,42cm e a artéria ilíaca externa esquerda (AIEE o diâmetro médio de 0,39. O estudo hemodinâmico da aorta abdominal apresentou velocidade de pico sistólico médio de 104,00cm/s para AOR; 99,61cm/s para AOT; 85,47cm/s para AIED e 99,51cm/s para AIEE. Verificaram-se correlações de diferentes intensidades entre os diâmetros vasculares em diferentes pontos de tomadas e os fatores biométricos corpóreos (CRL. Correlações baixas foram observadas quando esses diâmetros foram confrontados com a idade.A duplex ultrasound system incorporating a pulsed wave Doppler ultrasound probe with conventional B-mode real-time imaging was used to evaluate the biometric and the hemodynamic of abdominal aorta and external iliac arteries of a hundred and thirty one normal dogs. Results of biometrics of abdominal aorta, presented a mean diameter of 0.80cm in its diaphragmatic segment (AOD; 0.74cm in its segment caudal to the renal arteries (AOR and 0.69cm in the segment cranial to its termination (AOT. The right-external-iliac artery (AIED presented a mean diameter of 0.42cm and the left-external iliac artery (AIEE a mean diameter of 0.39cm. The hemodynamic study of the abdominal aorta presented a medium systolic peak velocity to AOR of 104cm per sec.; to AOT of 99.61cm per sec.; to AIED of 85.47cm per sec. and to AIEE of 99.51cm per sec. Correlations of different intensities between the vascular diameters have been verified between the

Spiral CT-angiography of the aorta

NARCIS (Netherlands)

Balm, R.; Eikelboom, B. C.; van Leeuwen, M. S.; Noordzij, J.

1994-01-01

AIMS: To determine whether the new technique of CT-angiography was accurate in displaying the complex anatomy of the aorta and its major branches. METHODS: Seventeen patients with a variety of aortic pathology were examined. Using a spiral CT-scanner a volumetric scan was made during injection of

Tensile characterisation of the aorta across quasi-static to blast loading strain rates

Science.gov (United States)

Magnus, Danyal; Proud, William; Haller, Antoine; Jouffroy, Apolline

2017-06-01

The dynamic tensile failure mechanisms of the aorta during Traumatic Aortic Injury (TAI) are poorly understood. In automotive incidents, where the aorta may be under strains of the order of 100/s, TAI is the second largest cause of mortality. In these studies, the proximal descending aorta is the most common site where rupture is observed. In particular, the transverse direction is most commonly affected due to the circumferential orientation of elastin, and hence the literature generally concentrates upon axial samples. This project extends these dynamic studies to the blast loading regime where strain-rates are of the order of 1000/s. A campaign of uniaxial tensile experiments are conducted at quasi-static, intermediate (drop-weight) and high (tensile Split-Hopkinson Pressure Bar) strain rates. In each case, murine and porcine aorta models are considered and the extent of damage assessed post-loading using histology. Experimental data will be compared against current viscoelastic models of the aorta under axial stress. Their applicability across strain rates will be discussed. Using a multi-disciplinary approach, the conditions applied to the samples replicate in vivo conditions, employing a blood simulant-filled tubular specimen surrounded by a physiological solution.

Production of a faithful realistic phantom to human head and thermal neutron flux measurement on the brain surface. Cooperative research

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Kazuyoshi; Kumada, Hiroaki; Kishi, Toshiaki; Torii, Yoshiya; Uchiyama, Junzo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Endo, Kiyoshi; Yamamoto, Tetsuya; Matsumura, Akira; Nose, Tadao [Tsukuba Univ., Tsukuba, Ibaraki (Japan)

2002-12-01

Thermal neutron flux is determined using the gold wires in current BNCT irradiation, so evaluation of arbitrary points after the irradiation is limited in the quantity of these detectors. In order to make up for the weakness, dose estimation of a patient is simulated by a computational dose calculation supporting system. In another way without computer simulation, a medical irradiation condition can be replicate experimentally using of realistic phantom which was produced from CT images by rapid prototyping technique. This phantom was irradiated at a same JRR-4 neutron beam as clinical irradiation condition of the patient and the thermal neutron distribution on the brain surface was measured in detail. This experimental evaluation technique using a realistic phantom is applicable to in vitro cell irradiation experiments for radiation biological effects as well as in-phantom experiments for dosimetry under the nearly medical irradiation condition of patient. (author)

Production of a faithful realistic phantom to human head and thermal neutron flux measurement on the brain surface. Cooperative research

CERN Document Server

Yamamoto, K; Kishi, T; Kumada, H; Matsumura, A; Nose, T; Torii, Y; Uchiyama, J; Yamamoto, T

2002-01-01

Thermal neutron flux is determined using the gold wires in current BNCT irradiation, so evaluation of arbitrary points after the irradiation is limited in the quantity of these detectors. In order to make up for the weakness, dose estimation of a patient is simulated by a computational dose calculation supporting system. In another way without computer simulation, a medical irradiation condition can be replicate experimentally using of realistic phantom which was produced from CT images by rapid prototyping technique. This phantom was irradiated at a same JRR-4 neutron beam as clinical irradiation condition of the patient and the thermal neutron distribution on the brain surface was measured in detail. This experimental evaluation technique using a realistic phantom is applicable to in vitro cell irradiation experiments for radiation biological effects as well as in-phantom experiments for dosimetry under the nearly medical irradiation condition of patient.

Shape of the dilated aorta in children with bicuspid aortic valve

International Nuclear Information System (INIS)

Mart, Christopher R; McNerny, Bryn E

2013-01-01

The dilated aorta in adults with bicuspid aortic valve has been shown to have different shapes, but it is not known if this occurs in children. This observational study was performed to determine if there are different shapes of the dilated aorta in children with bicuspid aortic valve and their association with age, gender, hemodynamic alterations, and degree of aortic enlargement. One hundred and eighty-seven echocardiograms done on pediatric patients (0 – 18 years) for bicuspid aortic valve, during 2008, were reviewed. Aortic valve morphology, shape/size of the aorta, and pertinent hemodynamic alterations were documented. Aortic dilation was felt to be present when at least one aortic segment had a z-score > 2.0; global aortic enlargement was determined by summing the aortic segment z-scores. The aortic shape was assessed by age, gender, valve morphology, and hemodynamic alterations. Aortic dilation was present in 104/187 patients. The aorta had six different shapes designated from S1 through S6. There was no association between the aortic shape and gender, aortic valve morphology, or hemodynamic abnormalities. S3 was the most common after the age of six years and was associated with the most significant degree of global aortic enlargement. The shape of the dilated aorta in children with bicuspid aortic valve does not occur in a uniform manner and multiple shapes are seen. S2 and S3 are most commonly seen. As aortic dilation becomes more significant, a single shape (S3) becomes the dominant pattern

The impact of anthropometric patient-phantom matching on organ dose: A hybrid phantom study for fluoroscopy guided interventions

International Nuclear Information System (INIS)

Johnson, Perry B.; Geyer, Amy; Borrego, David; Ficarrotta, Kayla; Johnson, Kevin; Bolch, Wesley E.

2011-01-01

Purpose: To investigate the benefits and limitations of patient-phantom matching for determining organ dose during fluoroscopy guided interventions. Methods: In this study, 27 CT datasets representing patients of different sizes and genders were contoured and converted into patient-specific computational models. Each model was matched, based on height and weight, to computational phantoms selected from the UF hybrid patient-dependent series. In order to investigate the influence of phantom type on patient organ dose, Monte Carlo methods were used to simulate two cardiac projections (PA/left lateral) and two abdominal projections (RAO/LPO). Organ dose conversion coefficients were then calculated for each patient-specific and patient-dependent phantom and also for a reference stylized and reference hybrid phantom. The coefficients were subsequently analyzed for any correlation between patient-specificity and the accuracy of the dose estimate. Accuracy was quantified by calculating an absolute percent difference using the patient-specific dose conversion coefficients as the reference. Results: Patient-phantom matching was shown most beneficial for estimating the dose to heavy patients. In these cases, the improvement over using a reference stylized phantom ranged from approximately 50% to 120% for abdominal projections and for a reference hybrid phantom from 20% to 60% for all projections. For lighter individuals, patient-phantom matching was clearly superior to using a reference stylized phantom, but not significantly better than using a reference hybrid phantom for certain fields and projections. Conclusions: The results indicate two sources of error when patients are matched with phantoms: Anatomical error, which is inherent due to differences in organ size and location, and error attributed to differences in the total soft tissue attenuation. For small patients, differences in soft tissue attenuation are minimal and are exceeded by inherent anatomical differences

3D Printing Openable Imaging Phantom Design

International Nuclear Information System (INIS)

Kim, Myoung Keun; Won, Jun Hyeok; Lee, Seung Wook

2017-01-01

The purpose of this study is to design an openable phantom that can replace the internal measurement bar used for contrast comparison in order to increase the efficiency of manufacturing imaging phantom used in the medical industry and to improve convenience using 3D printer. Phantom concept design, 3D printing, and Image reconstruction were defined as the scope of the thesis. Also, we study metal artifact reduction with openable phantom. We have designed a Openable phantom using 3D printing, and have investigated metal artifact reduction after inserting a metallic material inside the phantom. The openable phantom can be adjusted at any time to suit the user's experiment and can be easily replaced and useful.

The subresolution DaTSCAN phantom: a cost-effective, flexible alternative to traditional phantom technology.

Science.gov (United States)

Taylor, Jonathan C; Vennart, Nicholas; Negus, Ian; Holmes, Robin; Bandmann, Oliver; Lo, Christine; Fenner, John

2018-03-01

The Alderson striatal phantom is frequently used to assess I-FP-CIT (Ioflupane) image quality and to test semi-quantification software. However, its design is associated with a number of limitations, in particular: unrealistic image appearances and inflexibility. A new physical phantom approach is proposed on the basis of subresolution phantom technology. The design incorporates thin slabs of attenuating material generated through additive manufacturing, and paper sheets with radioactive ink patterns printed on their surface, created with a conventional inkjet printer. The paper sheets and attenuating slabs are interleaved before scanning. Use of thin layers ensures that they cannot be individually resolved on reconstructed images. An investigation was carried out to demonstrate the performance of such a phantom in producing simplified I-FP-CIT uptake patterns. Single photon emission computed tomography imaging was carried out on an assembled phantom designed to mimic a healthy patient. Striatal binding ratio results and linear striatal dimensions were calculated from the reconstructed data and compared with that of 22 clinical patients without evidence of Parkinsonian syndrome, determined from clinical follow-up. Striatal binding ratio results for the fully assembled phantom were: 3.1, 3.3, 2.9 and 2.6 for the right caudate, left caudate, right putamen and right caudate, respectively. All were within two SDs of results derived from a cohort of clinical patients. Medial-lateral and anterior-posterior dimensions of the simulated striata were also within the range of values seen in clinical data. This work provides the foundation for the generation of a range of more clinically realistic, physical phantoms.

Mural Thrombus in the Normal-Appearing Descending Thoracic Aorta of a Chronic Smoker

Science.gov (United States)

Habib, Habib; Hsu, Judy; Winchell, Patricia Jo; Daoko, Joseph

2013-01-01

Thrombus formation in an atherosclerotic or aneurysmal descending thoracic aorta is a well-described, frequently encountered vascular condition. In comparison, thrombus formation in a normal-appearing descending thoracic aorta is reported far less often. We describe the case of a 46-year-old woman who had splenic and renal infarctions secondary to embolic showers from a large, mobile thrombus in a morphologically normal proximal descending thoracic aorta. After the patient underwent anticoagulation, stent-grafting, and surgical bypass to correct an arterial blockage caused by the stent-graft, she resumed a relatively normal life. In contrast with other cases of a thrombotic but normal-appearing descending thoracic aorta, this patient had no known malignancy or systemic coagulative disorders; her sole risk factor was chronic smoking. We discuss our patient's case and review the relevant medical literature, focusing on the effect of smoking on coagulation physiology. PMID:24391341

TAVR Through Heavily Calcified Aorta Following Atheroma Retrieval With the "Elevator" Technique.

Science.gov (United States)

Senguttuvan, N Boopathy; Ellozy, Sharif; Tejani, Furqan; Kovacic, Jason; Kini, Annapoorna S; Sharma, Samin K; Dangas, George D

2015-10-01

An 86-year-old Caucasian female with severe symptomatic, inoperable aortic stenosis was accepted for high-risk transfemoral transcatheter aortic valve replacement (TAVR) approach due to severe calcification of the aorta. During initial passage of a 22 Fr sheath, there was dislodgment with proximal migration of a circumferential tunnel of calcium from the infrarenal aorta. A novel "elevator" technique was used to secure and retrieve the dislodged aorta en bloc back to its original infrarenal aortic position and allow in situ fixation with stenting. A new TAVR system was then successfully placed through the stent and a 23 mm Edwards Sapien valve (Edwards Lifesciences) was implanted as planned. In case of calcification protruding into the lumen of the aorta and limiting the passage of the large valve delivery system sheath, the obstruction can be managed by stenting the calcification against the luminal wall under fluoroscopic and intravascular-ultrasound guidance, allowing successful passage of the valve delivery system. The elevator technique allows axial transportation of any calcified vascular fragments, should they become dislodged.

Development of an Arm Phantom for Testing Non-Invasive Blood Pressure Monitors

Science.gov (United States)

Anderson-Jackson, LaTecia D.

Approximately one in every three adults age 20 older are diagnosed with high blood pressure or hypertension. It is estimated that hypertension affects 78 million people in the United States, is equally prevalent in both men and woman (Crabtree, Stuart-Shor, & McAllister, 2013). In the United States, around 78% of people suffering from hypertension are aware of their condition, with only 68% using hypertensive medications to control their blood pressure (Writing Group et al., 2010). Clinically, blood pressure measurements may lack accuracy, which can be attributed to various factors, including device limitations, cuff mis-sizing and misplacement, white-coat effect, masked hypertension, and lifestyle factors. The development of an arm phantom to simulate physiologic properties of a human arm and arterial BP waveforms may allow us to better assess the accuracy of non-invasive blood pressure (NIBP) monitors. The objective of this study are to: (1) Develop an arm phantom to replicate physiological properties of the human arm, and (2) Incorporate the arm phantom into a mock circulatory flow loop to simulate different physiological blood pressure readings on the bench. A tissue mimicking material, styrene-ethylene-butylene-styrene (SEBS), a co-block polymer was used to develop the arm phantom for in-vitro testing. To determine the optimal mechanical properties for the arm phantom, individual arm components were isolated and tested. A protocol was developed to evaluate various components for optimal arm phantom development. Mechanical testing was conducted on 10%, 15%, and 20% SEBS gel samples for modulus of elasticity measurements in order to simulate physiological properties of the human arm. As a result of the SEBS polymer being a new material for this application, this investigation will contribute to resolving the limitations that occurred during experimentation. In this study, we demonstrated that although SEBS polymer may be an ideal material to use for simulating

Tratamiento endovascular de urgencia con endoprótesis de aneurisma roto disecado de aorta torácica: A propósito de un caso Emergency endovascular treatment with endoprosthesis of ruptured dissected aneurysm of thoracic aorta: Report of one case

Directory of Open Access Journals (Sweden)

José Lugo

2007-12-01

Full Text Available Los aneurismas de aorta torácica son menos comunes que los aneurismas de aorta abdominal y pueden encontrarse en aorta ascendente, arco aórtico, aorta descendente o en una combinación de estos segmentos. De estos aneurismas el 30% al 40% se originan en la aorta torácica descendente. En los aneurismas de aorta torácica existe una debilidad estructural de la pared de la aorta, que conlleva una dilatación arterial progresiva con eventual ruptura o disección. Aproximadamente, 50% de los aneurismas de aorta torácica son ateroscleróticos y ocurren como resultado de remodelado arterial y dilatación o a raíz de un metabolismo anormal del colágeno. La mayoría de los aneurismas de aorta torácica se descubren por casualidad durante la evaluación de otros problemas médicos. La meta del tratamiento de los aneurismas de aorta torácica, es prevenir la muerte debido a su ruptura. El riesgo de ruptura de los no tratados oscila entre 46% a 74% y la tasa de mortalidad por su ruptura es extremadamente alta. Los aneurismas de gran tamaño, en especial aquellos mayores de 6 cm, son más susceptibles de rupturas que los aneurismas de menor tamaño. El tratamiento endovascular, inicialmente desarrollado para los aneurismas de aorta abdominal, se introdujo en 1992 como una alternativa menos invasiva al tratamiento de cirugía abierta para los aneurismas de la aorta torácica descendente. En la actualidad, el injerto de stent endovascular en la aorta descendente o endoprótesis, recibe mayor atención como alternativa al reparo quirúrgico de los aneurismas de aorta torácica.Thoracic aortic aneurysms are less common than abdominal aortic aneurysms and can be found in ascending aorta, aortic arch, descending aorta or in a combination of these segments. 30% to 40% of these aneurysms are originated in thoracic descending aorta. In thoracic aortic aneurysms there exists a structural wall weakness that leads to a progressive arterial dilation with eventual

Surgery for pseudoaneurysm of the ascending aorta under moderate hypothermia

Directory of Open Access Journals (Sweden)

Lee Dong-Hyup

2011-09-01

Full Text Available Abstract Pseudoaneurysm of the ascending aorta is a rare complication after cardiac surgery. Particularly, pseudoaneurysm due to postoperative infection in the ascending aorta requires surgical treatment with antibiotics. If a large sized pseudoaneurysm is located at the retrosternal space, then there is a very high risk of massive bleeding from rupture during performance of resternotomy. To avoid this risk, we performed femoro-femoral bypass under moderate hypothermia with transient circulatory arrest, and we report here on the successful result of this case.

Protective effect of soybeans as protein source in the diet against cadmium-aorta redox and morphological alteration

International Nuclear Information System (INIS)

Pérez Díaz, Matías F.F.; Acosta, Mariano; Mohamed, Fabián H.; Ferramola, Mariana L.; Oliveros, Liliana B.; Gimenez, María S.

2013-01-01

We investigated the effects of cadmium exposition on thoracic aorta redox status and morphology, and the putative protective effect of soybeans in the diet. Male Wistar rats were separated into 6 groups: 3 fed with a diet containing casein and 3 containing soybeans, as protein source. Within each protein group, one was given tap water (control) and the other two tap water containing 15 and 100 ppm of Cd 2+ , respectively, for two months. In rats fed with casein diet, 15 ppm of Cd induced an increase of thiobarbituric acid-reactive substances (TBARS), and of the catalase (CAT) and glutathione peroxidase (GPx) activities, which were even higher with 100 ppm of Cd 2+ , in aorta. Also, 100 ppm Cd 2+ exposure increased superoxide dismutase (CuZnSOD) activity; CAT, GPX, SOD, Nrf2 and metallothioneine II mRNA expressions and CAT, GPx and NOX-2 protein levels, compared with control. Aorta endothelial and cytoplasmic alterations were observed. However, with the soybeans diet, 15 and 100 ppm of Cd 2+ did not modify TBARS levels; CAT, GPX and Nrf2 mRNA expressions; CAT, GPx and NOX-2 protein; and the aorta morphology, compared with control. The soybean diet attenuates the redox changes and protects against morphological alterations induced, in a dose-dependent way, by Cd in aorta. - Highlights: • Under casein diet, 100 ppm Cd 2+ in drinking water induces oxidative stress in aorta. • Under casein diet, 100 ppm Cd 2+ increases Nrf2, MT II and NOX2 expressions in aorta. • Under casein diet, 100 ppm Cd 2+ induces morphological changes in rat aorta. • The soybean diet attenuates the redox changes induced by Cd in rat aorta. • The soybean diet attenuates morphological alterations induced by Cd in rat aorta

Protective effect of soybeans as protein source in the diet against cadmium-aorta redox and morphological alteration

Energy Technology Data Exchange (ETDEWEB)

Pérez Díaz, Matías F.F.; Acosta, Mariano; Mohamed, Fabián H.; Ferramola, Mariana L.; Oliveros, Liliana B.; Gimenez, María S., E-mail: marisofigime44@gmail.com

2013-11-01

We investigated the effects of cadmium exposition on thoracic aorta redox status and morphology, and the putative protective effect of soybeans in the diet. Male Wistar rats were separated into 6 groups: 3 fed with a diet containing casein and 3 containing soybeans, as protein source. Within each protein group, one was given tap water (control) and the other two tap water containing 15 and 100 ppm of Cd{sup 2+}, respectively, for two months. In rats fed with casein diet, 15 ppm of Cd induced an increase of thiobarbituric acid-reactive substances (TBARS), and of the catalase (CAT) and glutathione peroxidase (GPx) activities, which were even higher with 100 ppm of Cd{sup 2+}, in aorta. Also, 100 ppm Cd{sup 2+} exposure increased superoxide dismutase (CuZnSOD) activity; CAT, GPX, SOD, Nrf2 and metallothioneine II mRNA expressions and CAT, GPx and NOX-2 protein levels, compared with control. Aorta endothelial and cytoplasmic alterations were observed. However, with the soybeans diet, 15 and 100 ppm of Cd{sup 2+} did not modify TBARS levels; CAT, GPX and Nrf2 mRNA expressions; CAT, GPx and NOX-2 protein; and the aorta morphology, compared with control. The soybean diet attenuates the redox changes and protects against morphological alterations induced, in a dose-dependent way, by Cd in aorta. - Highlights: • Under casein diet, 100 ppm Cd{sup 2+} in drinking water induces oxidative stress in aorta. • Under casein diet, 100 ppm Cd{sup 2+} increases Nrf2, MT II and NOX2 expressions in aorta. • Under casein diet, 100 ppm Cd{sup 2+} induces morphological changes in rat aorta. • The soybean diet attenuates the redox changes induced by Cd in rat aorta. • The soybean diet attenuates morphological alterations induced by Cd in rat aorta.

MR imaging of the toracic aorta

International Nuclear Information System (INIS)

Garbagnati, F.; Castoldi, M.C.; Bianchini, E.

1988-01-01

Various pathological conditions of the thoracic aorta were studied by MR Imaging in 31 patients: 23 were aneurysms (branching and non-branching), 2 artero-venous fistulae, 2 aortic prostheses, 2 Marfan's syndromes, 1 coronary sinus aneurysm, and 1 isthmic stenosis. MRI studies were always performed on patients who had been examined by other imaging procedures. A comparative study was carried out on the results of MRI, angiography, computerized tomography, and ultrasounds. The possibility of propedeutic protocol was explored. Our experience, in accordance with the literature on the subject, indicates MRI as the procedure of choice in the study of aneurysms of the toracic aorta. The advantages offered by MRI-the high natural contrast between circulating blood and the supporting structures, the possibility of obtaining multiplanar images as well as data on intraluminal, parietal, and extraparietal conditions-make it a highly competitive procedure if compared to either CT or angiography. While awaiting further evidence, the use of a propedeutic protocol in non-aneurysmatic diseases is still not advisable, due to insufficient patient population, and to the lack of a consistent literature on the subject

A computer-simulated liver phantom (virtual liver phantom) for multidetector computed tomography evaluation

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Funama, Yoshinori [Kumamoto University, Department of Radiological Sciences, School of Health Sciences, Kumamoto (Japan); Awai, Kazuo; Nakayama, Yoshiharu; Liu, Da; Yamashita, Yasuyuki [Kumamoto University, Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto (Japan); Miyazaki, Osamu; Goto, Taiga [Hitachi Medical Corporation, Tokyo (Japan); Hori, Shinichi [Gate Tower Institute of Image Guided Therapy, Osaka (Japan)

2006-04-15

The purpose of study was to develop a computer-simulated liver phantom for hepatic CT studies. A computer-simulated liver phantom was mathematically constructed on a computer workstation. The computer-simulated phantom was calibrated using real CT images acquired by an actual four-detector CT. We added an inhomogeneous texture to the simulated liver by referring to CT images of chronically damaged human livers. The mean CT number of the simulated liver was 60 HU and we added numerous 5-to 10-mm structures with 60{+-}10 HU/mm. To mimic liver tumors we added nodules measuring 8, 10, and 12 mm in diameter with CT numbers of 60{+-}10, 60{+-}15, and 60{+-}20 HU. Five radiologists visually evaluated similarity of the texture of the computer-simulated liver phantom and a real human liver to confirm the appropriateness of the virtual liver images using a five-point scale. The total score was 44 in two radiologists, and 42, 41, and 39 in one radiologist each. They evaluated that the textures of virtual liver were comparable to those of human liver. Our computer-simulated liver phantom is a promising tool for the evaluation of the image quality and diagnostic performance of hepatic CT imaging. (orig.)

Upper gastrointestinal bleeding, aneurismatic dilatation of the thoracic aorta and filling defect on the esophagogram

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Naschitz, J.E.; Bassan, H.; Lazarov, N.; Grishkan, A.

1982-06-01

A patient is described with an aneurysm of the thoracic aorta, which has ruptured into the esophagus. An esophageal X-ray contrast study has revealed a filling defect at the contact site of the esophagus and the aortic aneurysm. The filling defect was due to a clot protruding from the aorta into the esophagus. This unique case calls attention to a diagnostic triad: upper gastrointestinal bleeding, aneurysm of the thoracic aorta, and filling defect in the esophagus at its site of contact with the enlarged aorta. This triad suggested aortoesophageal fistula (AEF) in the patient and could help in the diagnosis of atypical cases of AEF, where thoracic aortography has not been performed initially.

Upper gastrointestinal bleeding, aneurismatic dilatation of the thoracic aorta and filling defect on the esophagogram

International Nuclear Information System (INIS)

Naschitz, J.E.; Bassan, H.; Lazarov, N.; Grishkan, A.; Haifa Univ.; Haifa Univ.

1982-01-01

A patient is described with an aneurysm of the thoracic aorta, which has ruptured into the esophagus. An esophageal X-ray contrast study has revealed a filling defect at the contact site of the esophagus and the aortic aneurysm. The filling defect was due to a clot protruding from the aorta into the esophagus. This unique case calls attention to a diagnostic triad: upper gastrointestinal bleeding, aneurysm of the thoracic aorta, and filling defect in the esophagus at its site of contact with the enlarged aorta. This triad suggested aortoesophageal fistula (AEF) in the patient and could help in the diagnosis of atypical cases of AEF, where thoracic aortography has not been performed initially. (orig.) [de

Gadolinium-enhanced MR angiography of the thoracoabdominal aorta diseases

International Nuclear Information System (INIS)

D'Ippolito, Giuseppe; Wolosker, Nelson; Galvao Filho, Mario; Kalil, Jorge A.; Wolosker, Angela; Borri, Maria Lucia

1998-01-01

Gadolinium-enhanced MR angiography (GEMRA) of the thoracoabdominal aorta is a noninvasive technique that can rapidly delineate the branch vessels diseases, without flow or respiration artifacts, obtained with non contrast MRA. The objective of this paper is to show the main clinical applications of GEMRA, compared to non contrast sequences. We have evaluated 30 patients with thorocoabdominal aorta diseases. These patients have been examined with GEMRA (3D, FFE sequences) obtained after 30 mlIV contrast injection and non contrast MRA (2D-TOF sequences). In our experience, gadolinium-enhanced MRA is a high resolution and speedy technique with advantages over non contrast MRA. (author)

Experiencia en el manejo endovascular para el tratamiento de la aorta torácica Experience in endovascular management for thoracic aorta treatment

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Juan G Barrera

2007-12-01

Full Text Available Antecedentes: el tratamiento endovascular ofrece la posibilidad de cubrir el origen de la disección y evitar que progrese hasta aneurisma de la aorta, y con ello demuestra una reducción en la mortalidad hasta del 16%. Objetivo: evaluar los resultados quirúrgicos en términos de morbi-mortalidad de los pacientes sometidos a manejo endovascular de las lesiones de la aorta torácica en la Fundación Cardiovascular de Colombia desde 2003 hasta 2005. Diseño-método: estudio longitudinal tipo descriptivo retrospectivo, en el que se evaluaron las historias clínicas de todos los pacientes sometidos a manejo endovascular de patología toracoabdominal; en éste sólo se incluyeron los pacientes con procedimientos de la aorta torácica, desde 2003 hasta 2005. El análisis de los datos se realizó en Stata/SE 8,0. Resultados: se realizaron procedimientos de aorta torácica en 16 pacientes. El 75% de los pacientes eran hombres con edad promedio de 55,9 ± 12,6 años. El 87,5% (14 pacientes presentaban disección aórtica tipo A o B; un paciente transección traumática de la aorta y un paciente aneurisma de aorta torácica descendente. Las disecciones agudas se presentaron en 78,6% (11 pacientes y las crónicas en 21,4% (3 pacientes. El promedio de endoprótesis usadas fue de 2,8 ± 1. La estancia en la unidad de cuidados intensivos fue de 3 ± 2,7 días. El 81,3% de los pacientes no presentaron complicaciones mayores. La mortalidad fue del 18,7% (3 pacientes. A todos se les realizó control post-operatorio con tomografía axial computarizada, con evolución satisfactoria. Conclusión: de acuerdo con los reportes de la literatura con mayor casuística, se considera que el manejo endovascular para el tratamiento de la disección, aneurisma o trauma aórtico es un procedimiento confiable que disminuye la morbi-mortalidad.Antecedents: endovascular treatment has the possibility of covering the dissection origin and to avoid its progression to aortic

Over length quantification of the multiaxial mechanical properties of the ascending, descending and abdominal aorta using Digital Image Correlation.

Science.gov (United States)

Peña, Juan A; Corral, Victoria; Martínez, Miguel A; Peña, Estefanía

2018-01-01

In this paper, we hypothesize that the biaxial mechanical properties of the aorta may be dependent on arterial location. To demonstrate any possible position-related difference, our study analyzed and compared the biaxial mechanical properties of the ascending thoracic aorta, descending thoracic aorta and infrarenal abdominal aorta stemming from the same porcine subjects, and reported values of constitutive parameters for well-known strain energy functions, showing how these mechanical properties are affected by location along the aorta. When comparing ascending thoracic aorta, descending thoracic aorta and infrarenal abdominal aorta, abdominal tissues were found to be stiffer and highly anisotropic. We found that the aorta changed from a more isotropic to a more anisotropic tissue and became progressively less compliant and stiffer with the distance to the heart. We observed substantial differences in the anisotropy parameter between aortic samples where abdominal samples were more anisotropic and nonlinear than the thoracic samples. The phenomenological model was not able to capture the passive biaxial properties of each specific porcine aorta over a wide range of biaxial deformations, showing the best prediction root mean square error ε=0.2621 for ascending thoracic samples and, especially, the worst for the infrarenal abdominal samples ε=0.3780. The micro-structured model with Bingham orientation density function was able to better predict biaxial deformations (ε=0.1372 for ascending thoracic aorta samples). The root mean square error of the micro-structural model and the micro-structured model with von Mises orientation density function were similar for all positions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cadaveric aorta implantation for aortic graft infection.

Science.gov (United States)

Ali, Asad; Bahia, Sandeep S S; Ali, Tahir

2016-01-01

This case report describes a 73-year-old gentleman who underwent explantation of an infected prosthetic aorto-iliac graft and replacement with a cryopreserved thoracic and aorto-iliac allograft. The patient has been followed up a for more than a year after surgery and remains well. After elective tube graft repair of his abdominal aortic aneurysm (AAA) in 2003, he presented to our unit in 2012 in cardiac arrest as a result of a rupture of the distal graft suture line due to infection. After resuscitation he underwent aorto-bifemoral grafting using a cuff of the original aortic graft proximally. Distally the new graft was anastomosed to his common femoral arteries, with gentamicin beads left in situ. Post discharge the patient was kept under close surveillance with serial investigations including nuclear scanning, however it became apparent that his new graft was infected and that he would require aortic graft replacement, an operation with a mortality of at least 50%. The patient underwent the operation and findings confirmed a synthetic graft infection. This tube graft was explanted and a cryopreserved aorta was used to the refashion the abdominal aorta and its bifurcation. The operation required a return to theatre day one post operatively for a bleeding side branch, which was repaired. The patient went on to make a full recovery stepping down from the intensive therapy unit day 6 post operatively and went on to be discharged 32 days after his cryopreserved aorta implantation. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

A multimodality vascular imaging phantom of an abdominal aortic aneurysm with a visible thrombus

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Allard, Louise; Chayer, Boris; Qin Zhao [Laboratory of Biorheology and Medical Ultrasonics, Research Center, University of Montreal Hospital (CRCHUM), Quebec H2L 2W5 (Canada); Soulez, Gilles [Department of Radiology, University of Montreal Hospital (CHUM), Quebec H2L 2M1 (Canada); Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal, Quebec H3T 1J4 (Canada); Institute of Biomedical Engineering, University of Montreal, Quebec H3T 1J4 (Canada); Roy, David [Institute of Biomedical Engineering, University of Montreal, Quebec H3T 1J4 (Canada); Cloutier, Guy [Laboratory of Biorheology and Medical Ultrasonics, Research Center, University of Montreal Hospital (CRCHUM), Quebec H2L 2W5 (Canada); Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal, Quebec H3T 1J4 (Canada); Institute of Biomedical Engineering, University of Montreal, Quebec H3T 1J4 (Canada)

2013-06-15

Purpose: With the continuous development of new stent grafts and implantation techniques, it has now become technically feasible to treat abdominal aortic aneurysms (AAA) with challenging anatomy using endovascular repair with standard, fenestrated, or branched stent-grafts. In vitro experimentations are very useful to improve stent-graft design and conformability or imaging guidance for stent-graft delivery or follow-up. Vascular replicas also help to better understand the limitation of endovascular approaches in challenging anatomy and possibly improve surgical planning or training by practicing high risk clinical procedures in the laboratory to improve outcomes in the operating room. Most AAA phantoms available have a very basic anatomy, which is not representative of the clinical reality. This paper presents a method of fabrication of a realistic AAA phantom with a visible thrombus, as well as some mechanical properties characterizing such phantom. Methods: A realistic AAA geometry replica of a real patient anatomy taken from a multidetector computed tomography (CT) scan was manufactured. To demonstrate the multimodality imaging capability of this new phantom with a thrombus visible in magnetic resonance (MR) angiography, CT angiography (CTA), digital subtraction angiography (DSA), and ultrasound, image acquisitions with all these modalities were performed by using standard clinical protocols. Potential use of this phantom for stent deployment was also tested. A rheometer allowed defining hyperelastic and viscoelastic properties of phantom materials. Results: MR imaging measurements of SNR and CNR values on T1 and T2-weighted sequences and MR angiography indicated reasonable agreement with published values of AAA thrombus and abdominal components in vivo. X-ray absorption also lay within normal ranges of AAA patients and was representative of findings observed on CTA, fluoroscopy, and DSA. Ultrasound propagation speeds for developed materials were also in

A multimodality vascular imaging phantom of an abdominal aortic aneurysm with a visible thrombus

International Nuclear Information System (INIS)

Allard, Louise; Chayer, Boris; Qin Zhao; Soulez, Gilles; Roy, David; Cloutier, Guy

2013-01-01

Purpose: With the continuous development of new stent grafts and implantation techniques, it has now become technically feasible to treat abdominal aortic aneurysms (AAA) with challenging anatomy using endovascular repair with standard, fenestrated, or branched stent-grafts. In vitro experimentations are very useful to improve stent-graft design and conformability or imaging guidance for stent-graft delivery or follow-up. Vascular replicas also help to better understand the limitation of endovascular approaches in challenging anatomy and possibly improve surgical planning or training by practicing high risk clinical procedures in the laboratory to improve outcomes in the operating room. Most AAA phantoms available have a very basic anatomy, which is not representative of the clinical reality. This paper presents a method of fabrication of a realistic AAA phantom with a visible thrombus, as well as some mechanical properties characterizing such phantom. Methods: A realistic AAA geometry replica of a real patient anatomy taken from a multidetector computed tomography (CT) scan was manufactured. To demonstrate the multimodality imaging capability of this new phantom with a thrombus visible in magnetic resonance (MR) angiography, CT angiography (CTA), digital subtraction angiography (DSA), and ultrasound, image acquisitions with all these modalities were performed by using standard clinical protocols. Potential use of this phantom for stent deployment was also tested. A rheometer allowed defining hyperelastic and viscoelastic properties of phantom materials. Results: MR imaging measurements of SNR and CNR values on T1 and T2-weighted sequences and MR angiography indicated reasonable agreement with published values of AAA thrombus and abdominal components in vivo. X-ray absorption also lay within normal ranges of AAA patients and was representative of findings observed on CTA, fluoroscopy, and DSA. Ultrasound propagation speeds for developed materials were also in

Ovariectomy increases the participation of hyperpolarizing mechanisms in the relaxation of rat aorta.

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Ana Sagredo

Full Text Available This study examines the downstream NO release pathway and the contribution of different vasodilator mediators in the acetylcholine-induced response in rat aorta 5-months after the loss of ovarian function. Aortic segments from ovariectomized and control female Sprague-Dawley rats were used to measure: the levels of superoxide anion, the superoxide dismutases (SODs activity, the cGMP formation, the cGMP-dependent protein kinase (PKG activity and the involvement of NO, cGMP, hydrogen peroxide and hyperpolarizing mechanisms in the ACh-induced relaxation. The results showed that ovariectomy did not alter ACh-induced relaxation; incubation with L-NAME, a NO synthase inhibitor, decreased the ACh-induced response to a lesser extent in aorta from ovariectomized than from control rats, while ODQ, a guanylate cyclase inhibitor, decreased that response to a similar extent; the blockade of hyperpolarizing mechanisms, by precontracting arteries with KCl, decreased the ACh-induced response to a greater extent in aortas from ovariectomized than those from control rats; catalase, that decomposes hydrogen peroxide, decreased the ACh-induced response only in aorta from ovariectomized rats. In addition, ovariectomy increased superoxide anion levels and SODs activity, decreased cGMP formation and increased PKG activity. Despite the increased superoxide anion and decreased cGMP in aorta from ovariectomized rats, ACh-induced relaxation is maintained by the existence of hyperpolarizing mechanisms in which hydrogen peroxide participates. The greater contribution of hydrogen peroxide in ACh-induced relaxation is due to increased SOD activity, in an attempt to compensate for increased superoxide anion formation. Increased PKG activity could represent a redundant mechanism to ensure vasodilator function in the aorta of ovariectomized rats.

Estimation of prenatal aorta intima-media thickness from ultrasound examination

Science.gov (United States)

Veronese, E.; Tarroni, G.; Visentin, S.; Cosmi, E.; Linguraru, M. G.; Grisan, E.

2014-10-01

Prenatal events such as intrauterine growth restriction and increased cardiovascular risk in later life have been shown to be associated with an increased intima-media thickness (aIMT) of the abdominal aorta in the fetus. In order to assess and manage atherosclerosis and cardiovascular disease risk in adults and children, in recent years the measurement of abdominal and carotid artery thickness has gained a growing appeal. Nevertheless, no computer aided method has been proposed for the analysis of prenatal vessels from ultrasound data, yet. To date, these measurements are being performed manually on ultrasound fetal images by skilled practitioners. The aim of the presented study is to introduce an automatic algorithm that identifies abdominal aorta and estimates its diameter and aIMT from routine third trimester ultrasonographic fetal data. The algorithm locates the aorta, then segments it and, by modeling the arterial wall longitudinal sections by means of a gaussian mixture, derives a set of measures of the aorta diameter (aDiam) and of the intima-media thickness (aIMT). After estimating the cardiac cycle, the mean diameter and the aIMT at the end-diastole phase are computed. Considering the aIMT value for each subject, the correlation between automatic and manual end-diastolic aIMT measurements is 0.91 in a range of values 0.44-1.10 mm, corresponding to both normal and pathological conditions. The automatic system yields a mean relative error of 19%, that is similar to the intra-observer variability (14%) and much lower that the inter-observer variability (42%). The correlation between manual and automatic measurements and the small error confirm the ability of the proposed system to reliably estimate aIMT values in prenatal ultrasound sequences, reducing measurement variability and suggesting that it can be used for an automatic assessment of aIMT. Preliminary results have been presented in E Veronese, E Cosmi, S Visentin, E Grisan: 'Semiautomatic estimation

Effect of phantom voxelization in CT simulations

International Nuclear Information System (INIS)

Goertzen, Andrew L.; Beekman, Freek J.; Cherry, Simon R.

2002-01-01

In computer simulations of x-ray CT systems one can either use continuous geometrical descriptions for phantoms or a voxelized representation. The voxelized approach allows arbitrary phantoms to be defined without being confined to geometrical shapes. The disadvantage of the voxelized approach is that inherent errors are introduced due to the phantom voxelization. To study effects of phantom discretization, analytical CT simulations were run for a fan-beam geometry with phantom voxel sizes ranging from 0.0625 to 2 times the reconstructed pixel size and noise levels corresponding to 10 3 -10 7 photons per detector pixel prior to attenuation. The number of rays traced per detector element was varied from 1 to 16. Differences in the filtered backprojection images caused by changing the phantom matrix sizes and number of rays traced were assessed by calculating the difference between reconstructions based on the finest matrix and coarser matrix simulations. In noise free simulations, all phantom matrix sizes produced a measurable difference in comparison with the finest phantom matrix used. When even a small amount of noise was added to the projection data, the differences due to the phantom discretization were masked by the noise, and in all cases there was almost no improvement by using a phantom matrix that was more than twice as fine as the reconstruction matrix. No substantial improvement was achieved by tracing more than 4 rays per detector pixel

Effect of camelina oil on the structure of aortas in rats

DEFF Research Database (Denmark)

Pawlowska, Marta; Harrison, Adrian Paul; Piersiak, Tomasz

2016-01-01

The aim of the present study was to determine whether a disturbance of hormonal homeostasis caused by ovariectomy influences the elasticity and wall structure of the abdominal aorta and whether camelina oil administration has an effect on the properties of the abdominal aorta in rats after...... ovariectomy. Forty Wistar female rats (220-240 g) were used in the experiment: 10 animals underwent a sham ovary repositioning operation (SHO), and 30 were ovariectomized (OVX). After 7 days of convalescence, the SHO rats and OVX1 rats were given physiological saline intragastrically for 6 weeks, while......), and images were obtained by light and confocal microscopy. Ovariectomy caused a significant decrease in the elasticity of the aorta, as well as in the volume of collagen III and elastin in the tunica intima and media, but no changes in the volume of collagen I, the total wall thickness or the thickness...

The Japanese adult, child and infant phantoms

International Nuclear Information System (INIS)

Cristy, Mark; Egbert, Stephen D.

1987-01-01

The mathematical phantom for adult Japanese atomic-bomb survivors is a modification of the 57-kg ORNL (Oak Ridge National Laboratory) phantom for Western 15-year-old males and adult females. For younger Japanese survivors mathematical phantoms were similarly modified from the 18 and 9 kg ORNL phantoms for Western 5- and 1-year-olds, respectively. To make the phantom correspond more closely with dimensions and organ sizes recommended for Japanese adults by Maruyama and coworkers (cf E184), changes were made in the size of the lungs, the pancreas, the thyroid, and the testes and in the length of the legs. Also, the head-and-neck region was modified to improve the dose estimates for the thyroid from external radiation, after the ideas of Nagarajan et al. The arms were separated from the trunk to represent more accurately the shielding by the phantom in external exposures. Furthermore, provisions were made to provide a phantom in a kneeling posture. The elemental composition of the tissues was changed to that given by Kerr. The resulting phantom is slightly smaller in mass (55 kg). Details of these changes are given

Phantom cosmologies and fermions

International Nuclear Information System (INIS)

Chimento, Luis P; Forte, Monica; Devecchi, Fernando P; Kremer, Gilberto M

2008-01-01

Form invariance transformations can be used for constructing phantom cosmologies starting with conventional cosmological models. In this work we reconsider the scalar field case and extend the discussion to fermionic fields, where the 'phantomization' process exhibits a new class of possible accelerated regimes. As an application we analyze the cosmological constant group for a fermionic seed fluid

A statistically defined anthropomorphic software breast phantom

International Nuclear Information System (INIS)

Lau, Beverly A.; Reiser, Ingrid; Nishikawa, Robert M.; Bakic, Predrag R.

2012-01-01

Purpose: Digital anthropomorphic breast phantoms have emerged in the past decade because of recent advances in 3D breast x-ray imaging techniques. Computer phantoms in the literature have incorporated power-law noise to represent glandular tissue and branching structures to represent linear components such as ducts. When power-law noise is added to those phantoms in one piece, the simulated fibroglandular tissue is distributed randomly throughout the breast, resulting in dense tissue placement that may not be observed in a real breast. The authors describe a method for enhancing an existing digital anthropomorphic breast phantom by adding binarized power-law noise to a limited area of the breast. Methods: Phantoms with (0.5 mm) 3 voxel size were generated using software developed by Bakic et al. Between 0% and 40% of adipose compartments in each phantom were replaced with binarized power-law noise (β = 3.0) ranging from 0.1 to 0.6 volumetric glandular fraction. The phantoms were compressed to 7.5 cm thickness, then blurred using a 3 × 3 boxcar kernel and up-sampled to (0.1 mm) 3 voxel size using trilinear interpolation. Following interpolation, the phantoms were adjusted for volumetric glandular fraction using global thresholding. Monoenergetic phantom projections were created, including quantum noise and simulated detector blur. Texture was quantified in the simulated projections using power-spectrum analysis to estimate the power-law exponent β from 25.6 × 25.6 mm 2 regions of interest. Results: Phantoms were generated with total volumetric glandular fraction ranging from 3% to 24%. Values for β (averaged per projection view) were found to be between 2.67 and 3.73. Thus, the range of textures of the simulated breasts covers the textures observed in clinical images. Conclusions: Using these new techniques, digital anthropomorphic breast phantoms can be generated with a variety of glandular fractions and patterns. β values for this new phantom are comparable

"INHIBITORY EFFECT OF ALUMINIUM ON KCL AND PHENYLEPHRINE INDUCED CONTRACTION IN ISOLATED RAT AORTA"

Directory of Open Access Journals (Sweden)

T. Mashhoodi

2004-10-01

Full Text Available It has been shown in some investigations that cardiovascular events are the main causes of death in hemodialysis patients. The exact etiology is unknown but some of the articles have reported a relation between aluminium ions in the dialysis solution and cardiovascular disorders. To determine the probable effect of aluminium on vasculature function, in vitro effects of aluminium ion on vasoconstriction induced by KCl (30 mM or phenylephrine (10 µM were investigated using isolated rat aorta. AlCl3 (1-4 mM decreased both KCl and phenylephrine induced contractions in a dose dependent manner (P<0.01. Complete inhibition of the contractions occurred using the higher doses of aluminium. Results of this study suggest that because of inhibitory effects of aluminium on vascular contractions, the probable cardiovascular dysfunction must be considered in aluminium intoxication.

Intraindividual assessment of the thoracic aorta using contrast and non-contrast-enhanced MR angiography

International Nuclear Information System (INIS)

Tengg-Kobligk, Hendrik von; Gruenberg, K.M.; Giesel, F.L.; Ley-Zaporozhan, J.; Ley, S.; Henninger, V.; Kauczor, H.U.; Radiologische Universitaetsklinik Heidelberg; Boeckler, D.; Krummenauer, F.

2009-01-01

To avoid intravenous contrast media application, new MRA sequences using inherent blood contrast are available. The clinical use of these non-contrast-enhanced MRA (non-CE-MRA) sequences is still limited for the aorta. Thus, the goal was to compare a standard CE-MRA with a non-CE-MRA for the thoracic aorta. Ethics committee approval and informed consent were obtained. CE-MRA and non-CE-MRA (1.5T) were performed in the same 50 healthy volunteers (mean age: 48). CE-MRA: GRE-Turbo-Flash-3D (1.2 x 1.2 x 1.6 mm 3 ), 0.15 mmol Gd/kg, TA 22 ± 2sec. Non-CE-MRA: Respiratory-and cardiac-gated, T 2-prepared 3D-trueFISP (1.2 x 1.2 x 1.3 mm 3 ), TA 14 ± 5 min. Assessment included (3 readers, consensus): image quality (sharpness of vessel wall, signal homogeneity, artifacts) at the ascending aorta, arch, descending aorta and supra-aortic vessels. The image quality in the ascending aorta was rated 'excellent' in 78 %, 'moderate' in 22 %, 'poor' in 0 % for non-CE-MRA versus 22 %, 50 %, and 28 % for CE-MRA (Cohen's kappa = 29 %, McNemar p < 0.001). In a comparison of non-CE-MRA versus CE-MRA, the aortic arch and descending aorta showed no significant difference (kappa = 58 %/p = 0.250 and kappa = 100 %/p 1.000, respectively). Supra-aortic vessels were rated 'excellent' 45 %/49 %, 'moderate' 30 %/49 % and 'poor' 13 %/2 %, 12 % of supra-aortic vessels were visualized < 1 cm at non-CE-MRA. (orig.)

Sonographic aorta/IVC cross-sectional area index for evaluation of dehydration in children.

Science.gov (United States)

Kwon, Hyuksool; Jung, Jae Yun; Lee, Jin Hee; Kwak, Young Ho; Kim, Do Kyun; Jung, Jin Hee; Chang, Ik Wan; Kim, Kyuseok

2016-09-01

Current studies have not found sufficient evidence to encourage the use of ultrasound for assessing dehydration in children. We introduce a new sonographic parameter, the "aorta/inferior vena cava (IVC) cross-sectional area index" (Ao/IVCA) measured just inferior to the xiphoid process, for the effective evaluation of dehydration in children. This is a prospective, observational study. We enrolled children who presented to the pediatric emergency department (PED) between May 2014 and January 2015. We measured the maximum diameter of the aorta from inner wall to inner wall, and the long and short axis diameters of IVC using a convex array transducer. Ao/IVCA was calculated and compared with aorta/IVC maximal diameter index (Ao/IVCD) and the clinical dehydration scale (CDS). A total of 34 children were enrolled. We found a statistically significant correlation between Ao/IVCA and CDS (R(2) = 0.30; P dehydration. The diagnostic performance of Ao/IVCA for dehydration might be higher than that of the method that uses the maximum diameter of IVC and the aorta. Copyright © 2016 Elsevier Inc. All rights reserved.

A comparison of reactive oxygen species metabolism in the rat aorta and vena cava: focus on xanthine oxidase.

Science.gov (United States)

Szasz, Theodora; Thompson, Janice M; Watts, Stephanie W

2008-09-01

Reactive oxygen species (ROS) are important mediators in vascular biology. Venous function, although relevant to cardiovascular disease, is still understudied. We compared aspects of ROS metabolism between a major artery (the aorta) and a major vein (the vena cava, VC) of the rat, with the hypothesis that venous ROS metabolism would be overall increased compared with its arterial counterpart. Superoxide and hydrogen peroxide (H2O2) release in basal conditions was higher in VC compared with aorta. The antioxidant capacity for H2O2 was also higher in VC than in aorta. Exogenous superoxide induced a higher contraction in VC compared with aorta. Protein expression of three major ROS metabolizing enzymes, xanthine oxidase (XO), CuZn-SOD, and catalase, was higher in VC compared with aorta. Because XO seemed a likely source of the higher VC ROS levels, we examined it further and found higher mRNA expression and activity of XO in VC compared with aorta. We also investigated the impact of XO inhibition by allopurinol on aorta and VC functional responses to norepinephrine, ANG II, ET-1, and ACh. Maximal ET-1-mediated contraction was decreased by allopurinol in VC but not in the aorta. Our results suggest that there are overall differences in ROS metabolism between aorta and VC, with the latter operating normally at a higher set point, releasing but also being able to handle, higher ROS levels. We propose XO to be an important source for these differences. The result of this particular comparison may be reflective of a general arteriovenous contrast.

Tratamiento endovascular de las patologías de aorta -Estado del arte-: Parte 1 - Aneurismas de aorta abdominal Endovascular treatment of aortic pathologies -State of the art-: Part 1 - Aneurysms of abdominal aorta

Directory of Open Access Journals (Sweden)

Carlos E Uribe

2007-12-01

Full Text Available En la actualidad, el tratamiento endovascular de las patologías de aorta es una alternativa a la cirugía abierta. Éste ha demostrado ser seguro ya que arroja resultados iguales o superiores que el grupo quirúrgico. En este artículo se presenta el estado actual del tratamiento con endoprótesis de las patologías de aorta, así como las indicaciones, las contraindicaciones y el futuro del tratamiento con este tipo de dispositivos.Endovascular treatment of aortic pathologies is actually an alternative to open surgery. It has proven to be safe, showing similar or better results to those achieved by surgery. In this article, treatment of aortic pathologies by means of endoprosthesis is presented, as well as its indications, contraindications and future treatment with this kind of devices.

An improved Virtual Torso phantom

International Nuclear Information System (INIS)

Kramer, Gary H; Crowley, Paul

2000-01-01

The virtual phantom that was previously designed by the Human Monitoring Laboratory had some limitations. It contained no sternum and the ribs extended all the way round the torso, whereas in reality the central part of the chest is covered with a mixture of cartilage (ribs) and bone (sternum). The ribs were located below the chest wall which added to the thickness of the chest wall. The lungs did not touch the inner surface of the chest wall along their length due to the differences in curvature between the ellipsoidal lungs and the ellipsoidal cylinder that defined the torso. As a result there was extra intervening tissue between the lungs and the chest wall. This was shown to have a noticeable effect on the simulation of low energy photons. The virtual phantom has been redesigned and comparison of measured and calculated counting efficiencies shows that it is a good representation of both of LLNL or JAERI at all photon energies measured. The redesigned virtual phantom agrees to within 11% of the torsos' counting efficiency over the energy range 17 - 240 keV. Before modification, the virtual phantom's counting efficiency was a of factor three lower at 17 keV and a factor of two lower at 20 keV; now it is within 5% at 17 keV and within 10% at 20 keV. This phantom can now be reliably used to simulate lung counting. The virtual phantom still contains no sternum and the ribs extend all the way round the torso, whereas in reality the central part of the chest is covered with cartilage (ribs) and bone (sternum). However, the above results indicate that this is not a major flaw in the design of the virtual phantom, as agreement between the Monte Carlo results and experimental data is good. (author)

Optical coherence tomography detection of shear wave propagation in inhomogeneous tissue equivalent phantoms and ex-vivo carotid artery samples

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Razani, Marjan; Luk, Timothy W.H.; Mariampillai, Adrian; Siegler, Peter; Kiehl, Tim-Rasmus; Kolios, Michael C.; Yang, Victor X.D.

2014-01-01

In this work, we explored the potential of measuring shear wave propagation using optical coherence elastography (OCE) in an inhomogeneous phantom and carotid artery samples based on a swept-source optical coherence tomography (OCT) system. Shear waves were generated using a piezoelectric transducer transmitting sine-wave bursts of 400 μs duration, applying acoustic radiation force (ARF) to inhomogeneous phantoms and carotid artery samples, synchronized with a swept-source OCT (SS-OCT) imaging system. The phantoms were composed of gelatin and titanium dioxide whereas the carotid artery samples were embedded in gel. Differential OCT phase maps, measured with and without the ARF, detected the microscopic displacement generated by shear wave propagation in these phantoms and samples of different stiffness. We present the technique for calculating tissue mechanical properties by propagating shear waves in inhomogeneous tissue equivalent phantoms and carotid artery samples using the ARF of an ultrasound transducer, and measuring the shear wave speed and its associated properties in the different layers with OCT phase maps. This method lays the foundation for future in-vitro and in-vivo studies of mechanical property measurements of biological tissues such as vascular tissues, where normal and pathological structures may exhibit significant contrast in the shear modulus. PMID:24688822

Evaluation of the normal thoracic and abdominal aorta diameters by computerized tomography

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Lucarelli, Claudio Luiz

1995-01-01

The study was undertaken to evaluate, through computerized tomography, the diameters of the normal thoracic and abdominal aorta, as well as they are connected to gender, age and body surface area; and the ratio between measurements obtained at the ascending and descending limbs of the thoracic aorta, and between the abdominal aortic diameters. For that reason, we measured the widest anteroposterior diameters of the thoracic aortas at the levels of the arch, the root, the pulmonary artery, and the thoracic-abdominal transition, as well as the level of the emergence of the superior mesenteric artery, of the renal hila and just cephalad to the bifurcation of the abdominal aortas of 350 patients without cardiovascular diseases who had undergone computerized tomography of the thorax and/or abdomen for any other reasons. Observation and statistic analyses led us to conclude that: 1) both the thoracic and abdominal aortic diameters are reduced from their proximal to their distal portions; 2) the body surface influences the size of the aorta, although only extreme variations alter the vessel's caliber; 3) vessel diameter was observed to gradually increase with age; 4) men were found to have larger diameters than age matched women; 5) the ratio between the ascending and descending aortic diameters varies according to gender and age; 6) the relations between abdominal aortic diameters measured at the level of renal hila and cephalad to the bifurcation are independent from gender and age. But the relation between those measured at the level of the superior mesenteric artery and cephalad to the bifurcation are linked to gender, but not to age. (author)

Comparison of methods for individualized astronaut organ dosimetry: Morphometry-based phantom library versus body contour autoscaling of a reference phantom

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Sands, Michelle M.; Borrego, David; Maynard, Matthew R.; Bahadori, Amir A.; Bolch, Wesley E.

2017-11-01

One of the hazards faced by space crew members in low-Earth orbit or in deep space is exposure to ionizing radiation. It has been shown previously that while differences in organ-specific and whole-body risk estimates due to body size variations are small for highly-penetrating galactic cosmic rays, large differences in these quantities can result from exposure to shorter-range trapped proton or solar particle event radiations. For this reason, it is desirable to use morphometrically accurate computational phantoms representing each astronaut for a risk analysis, especially in the case of a solar particle event. An algorithm was developed to automatically sculpt and scale the UF adult male and adult female hybrid reference phantom to the individual outer body contour of a given astronaut. This process begins with the creation of a laser-measured polygon mesh model of the astronaut's body contour. Using the auto-scaling program and selecting several anatomical landmarks, the UF adult male or female phantom is adjusted to match the laser-measured outer body contour of the astronaut. A dosimetry comparison study was conducted to compare the organ dose accuracy of both the autoscaled phantom and that based upon a height-weight matched phantom from the UF/NCI Computational Phantom Library. Monte Carlo methods were used to simulate the environment of the August 1972 and February 1956 solar particle events. Using a series of individual-specific voxel phantoms as a local benchmark standard, autoscaled phantom organ dose estimates were shown to provide a 1% and 10% improvement in organ dose accuracy for a population of females and males, respectively, as compared to organ doses derived from height-weight matched phantoms from the UF/NCI Computational Phantom Library. In addition, this slight improvement in organ dose accuracy from the autoscaled phantoms is accompanied by reduced computer storage requirements and a more rapid method for individualized phantom generation

Diagnosis of supravalvar stenosis of aorta

International Nuclear Information System (INIS)

Shumskij, V.I.; Konstantinova, N.V.; Pokidkin, V.A.

1989-01-01

The authors analyzed the potentialities of combined radiodiagnosis of supravalvar stenosis (SS) and concomitant diseases of the heart and major vessels (Williams-Beuren syndrome) in 7 patients aged 7 mos. to 24 yrs. Polypositional chest and heart X-ray procedure, catheterization of the cardiac cavities, pulmonary artery and aorta, left ventriculography (6), right ventriculography (4) and angiopulmonography were used. The diagnostic potentialities of each method were defined

Composition of MRI phantom equivalent to human tissues

International Nuclear Information System (INIS)

Kato, Hirokazu; Kuroda, Masahiro; Yoshimura, Koichi; Yoshida, Atsushi; Hanamoto, Katsumi; Kawasaki, Shoji; Shibuya, Koichi; Kanazawa, Susumu

2005-01-01

We previously developed two new MRI phantoms (called the CAG phantom and the CAGN phantom), with T1 and T2 relaxation times equivalent to those of any human tissue at 1.5 T. The conductivity of the CAGN phantom is equivalent to that of most types of human tissue in the frequency range of 1 to 130 MHz. In this paper, the relaxation times of human tissues are summarized, and the composition of the corresponding phantoms are provided in table form. The ingredients of these phantoms are carrageenan as the gelling agent, GdCl 3 as a T1 modifier, agarose as a T2 modifier, NaCl (CAGN phantom only) as a conductivity modifier, NaN 3 as an antiseptic, and distilled water. The phantoms have T1 values of 202-1904 ms and T2 values of 38-423 ms when the concentrations of GdCl 3 and agarose are varied from 0-140 μmol/kg, and 0%-1.6%, respectively, and the CAGN phantom has a conductivity of 0.27-1.26 S/m when the NaCl concentration is varied from 0%-0.7%. These phantoms have sufficient strength to replicate a torso without the use of reinforcing agents, and can be cut by a knife into any shape. We anticipate the CAGN phantom to be highly useful and practical for MRI and hyperthermia-related research

Metabolism of arachidonic acid in 1 yr old New Zealand white (NZW) and watanabe heritable hyperlipidemic (WHHL) rabbit aortas

International Nuclear Information System (INIS)

Pfister, S.L.; Schmitz, J.M.; Willerson, J.T.; Campbell, W.B.

1986-01-01

This study was designed to characterize the metabolism of arachidonic acid (AA) in normal and atherosclerotic aortas. Segments of aortas were obtained from 1 yr old NZW rabbits, and WHHL rabbits, a genetic model of athero-sclerosis resembling familial hypercholesterolemia. Aortas were incubated at 37 0 C for 15 min with 14 C-AA (5 x 10 -5 M) during stimulation by A23187. The media was extracted using octadecylsilica columns and resolved into metabolites by reverse-phase HPLC. Prostaglandins (PGs) were identified by comigration of 14 C-metabolites with standards. The monoxygenated metabolites of AA (HETEs) were resolved by normal-phase HPLC, and their structures confirmed by GC-MS. In extracts from NZW and WHHL aortas, approximately 14% and 6% of the total radioactivity was converted to PGs and HETEs, respectively. The major PG produced by NZW and WHHL aortas was 6-keto PGF/sub 1α/ with lesser amounts of PGE 2 . Similarly, NZW and WHHL aortas produced primarily 12- and 15-HETE with lesser amounts of 11-, 9-, 8-, and 5-HETE. There were no qualitative differences between NZW and WHHL aortas in PG and HETE production. Therefore, despite extensive atherosclerosis in aortas of WHHL rabbits, the vessels maintain the ability to synthesize PGs and HETEs

Hybrid Approach of Aortic Diseases: Zone 1 Delivery and Volumetric Analysis on the Descending Aorta

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José Augusto Duncan

Full Text Available Abstract Introduction: Conventional techniques of surgical correction of arch and descending aortic diseases remains as high-risk procedures. Endovascular treatments of abdominal and descending thoracic aorta have lower surgical risk. Evolution of both techniques - open debranching of the arch and endovascular approach of the descending aorta - may extend a less invasive endovascular treatment for a more extensive disease with necessity of proximal landing zone in the arch. Objective: To evaluate descending thoracic aortic remodeling by means of volumetric analysis after hybrid approach of aortic arch debranching and stenting the descending aorta. Methods: Retrospective review of seven consecutive patients treated between September 2014 and August 2016 for diseases of proximal descending aorta (aneurysms and dissections by hybrid approach to deliver the endograft at zone 1. Computed tomography angiography were analyzed using a specific software to calculate descending thoracic aorta volumes pre- and postoperatively. Results: Follow-up was done in 100% of patients with a median time of 321 days (range, 41-625 days. No deaths or permanent neurological complications were observed. There were no endoleaks or stent migrations. Freedom from reintervention was 100% at 300 days and 66% at 600 days. Median volume reduction was of 45.5 cm3, representing a median volume shrinkage by 9.3%. Conclusion: Hybrid approach of arch and descending thoracic aorta diseases is feasible and leads to a favorable aortic remodeling with significant volume reduction.

Clinical evaluation of atherosclerosis and mechanical properties of the thoracic aorta

International Nuclear Information System (INIS)

Saiki, Atsushi

1991-01-01

To evaluate the aortic wall atherosclerosis, X-ray CT and ECG gated radionuclide angiography were performed in 25 subjects. They were classified into 17 normotensive group (N) and 8 hypertensive group (HT). The time-activity curve was generated using radionuclide angiography in the portion of the thoracic aorta. The aortic wall distensibility was expressed as 100ΔV/V 0 / PP, where ΔV was difference between maximum and minimum (V 0 ) counts of the aorta, and PP was pulse pressure. The degree of the aortic wall atherosclerosis was evaluated by X-ray CT. The aortic wall CT-score was calculated from the CT-scores measured whithin the region of interest of the other margin of the aorta and of the background by X-ray CT. There was a significant correlation between aortic wall CT-score and systolic blood pressure (r=0.59, p<0.01) or aortic wall distensibility (r=-0.74, p<0.01)), but no correlation existed between aortic wall CT-score and diastolic blood pressure (r=0.11, p:NS). The aortic wall distensibility was higher and the aortic wall CT-score was lower in N-group than in HT-group, whereas there was no difference of the radius of the aorta between both groups. These results suggest that the aortic wall atherosclerosis advanced progressively in hypertensive patients and systolic blood pressure was a good predictor of the degree of the aortic atherosclerosis. (author)

Differences in the Thoracic Aorta by Region and Sex in a Murine Model of Marfan Syndrome

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Francesc Jiménez-Altayó

2017-11-01

Full Text Available Marfan syndrome (MFS is a hereditary disorder of the connective tissue that causes life-threatening aortic aneurysm, which initiates at the aortic root and can progress into the ascending portion. However, analysis of ascending aorta reactivity in animal models of MFS has remained elusive. Epidemiologic evidence suggests that although MFS is equally prevalent in men and women, men are at a higher risk of aortic complications than non-pregnant women. Nevertheless, there is no experimental evidence to support this hypothesis. The aim of this study was to explore whether there are regional and sex differences in the thoracic aorta function of mice heterozygous for the fibrillin 1 (Fbn1 allele encoding a missense mutation (Fbn1C1039G/+, the most common class of mutation in MFS. Ascending and descending thoracic aorta reactivity was evaluated by wire myography. Ascending aorta mRNA and protein levels, and elastic fiber integrity were assessed by qRT-PCR, Western blotting, and Verhoeff-Van Gieson histological staining, respectively. MFS differently altered reactivity in the ascending and descending thoracic aorta by either increasing or decreasing phenylephrine contractions, respectively. When mice were separated by sex, contractions to phenylephrine increased progressively from 3 to 6 months of age in MFS ascending aortas of males, whereas contractions in females were unchanged. Endothelium-dependent relaxation was unaltered in the MFS ascending aorta of either sex; an effect related to augmented endothelium-dependent hyperpolarization-type dilations. In MFS males, the non-selective cyclooxygenase (COX inhibitor indomethacin prevented the MFS-induced enhancement of phenylephrine contractions linked to increased COX-2 expression. In MFS mice of both sexes, the non-selective nitric oxide synthase inhibitor L-NAME revealed negative feedback of nitric oxide on phenylephrine contractions, which was associated with upregulation of eNOS in females. Finally

Differences in the Thoracic Aorta by Region and Sex in a Murine Model of Marfan Syndrome

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Jiménez-Altayó, Francesc; Siegert, Anna-Maria; Bonorino, Fabio; Meirelles, Thayna; Barberà, Laura; Dantas, Ana P.; Vila, Elisabet; Egea, Gustavo

2017-01-01

Marfan syndrome (MFS) is a hereditary disorder of the connective tissue that causes life-threatening aortic aneurysm, which initiates at the aortic root and can progress into the ascending portion. However, analysis of ascending aorta reactivity in animal models of MFS has remained elusive. Epidemiologic evidence suggests that although MFS is equally prevalent in men and women, men are at a higher risk of aortic complications than non-pregnant women. Nevertheless, there is no experimental evidence to support this hypothesis. The aim of this study was to explore whether there are regional and sex differences in the thoracic aorta function of mice heterozygous for the fibrillin 1 (Fbn1) allele encoding a missense mutation (Fbn1C1039G/+), the most common class of mutation in MFS. Ascending and descending thoracic aorta reactivity was evaluated by wire myography. Ascending aorta mRNA and protein levels, and elastic fiber integrity were assessed by qRT-PCR, Western blotting, and Verhoeff-Van Gieson histological staining, respectively. MFS differently altered reactivity in the ascending and descending thoracic aorta by either increasing or decreasing phenylephrine contractions, respectively. When mice were separated by sex, contractions to phenylephrine increased progressively from 3 to 6 months of age in MFS ascending aortas of males, whereas contractions in females were unchanged. Endothelium-dependent relaxation was unaltered in the MFS ascending aorta of either sex; an effect related to augmented endothelium-dependent hyperpolarization-type dilations. In MFS males, the non-selective cyclooxygenase (COX) inhibitor indomethacin prevented the MFS-induced enhancement of phenylephrine contractions linked to increased COX-2 expression. In MFS mice of both sexes, the non-selective nitric oxide synthase inhibitor L-NAME revealed negative feedback of nitric oxide on phenylephrine contractions, which was associated with upregulation of eNOS in females. Finally, MFS ascending

Flow visualisation study of spiral flow in the aorta-renal bifurcation.

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Fulker, David; Javadzadegan, Ashkan; Li, Zuming; Barber, Tracie

2017-10-01

The aim of this study was to analyse the flow dynamics in an idealised model of the aorta-renal bifurcation using flow visualisation, with a particular focus on the effect of aorta-to-renal flow ratio and flow spirality. The recirculation length was longest when there was low flow in the renal artery and smaller in the presence of spiral flow. The results also indicate that patients without spiral flow or who have low flow in the renal artery due to the presence of stenosis may be susceptible to heightened development of atherosclerotic lesions.

Phantom motor execution facilitated by machine learning and augmented reality as treatment for phantom limb pain: a single group, clinical trial in patients with chronic intractable phantom limb pain.

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Ortiz-Catalan, Max; Guðmundsdóttir, Rannveig A; Kristoffersen, Morten B; Zepeda-Echavarria, Alejandra; Caine-Winterberger, Kerstin; Kulbacka-Ortiz, Katarzyna; Widehammar, Cathrine; Eriksson, Karin; Stockselius, Anita; Ragnö, Christina; Pihlar, Zdenka; Burger, Helena; Hermansson, Liselotte

2016-12-10

Phantom limb pain is a debilitating condition for which no effective treatment has been found. We hypothesised that re-engagement of central and peripheral circuitry involved in motor execution could reduce phantom limb pain via competitive plasticity and reversal of cortical reorganisation. Patients with upper limb amputation and known chronic intractable phantom limb pain were recruited at three clinics in Sweden and one in Slovenia. Patients received 12 sessions of phantom motor execution using machine learning, augmented and virtual reality, and serious gaming. Changes in intensity, frequency, duration, quality, and intrusion of phantom limb pain were assessed by the use of the numeric rating scale, the pain rating index, the weighted pain distribution scale, and a study-specific frequency scale before each session and at follow-up interviews 1, 3, and 6 months after the last session. Changes in medication and prostheses were also monitored. Results are reported using descriptive statistics and analysed by non-parametric tests. The trial is registered at ClinicalTrials.gov, number NCT02281539. Between Sept 15, 2014, and April 10, 2015, 14 patients with intractable chronic phantom limb pain, for whom conventional treatments failed, were enrolled. After 12 sessions, patients showed statistically and clinically significant improvements in all metrics of phantom limb pain. Phantom limb pain decreased from pre-treatment to the last treatment session by 47% (SD 39; absolute mean change 1·0 [0·8]; p=0·001) for weighted pain distribution, 32% (38; absolute mean change 1·6 [1·8]; p=0·007) for the numeric rating scale, and 51% (33; absolute mean change 9·6 [8·1]; p=0·0001) for the pain rating index. The numeric rating scale score for intrusion of phantom limb pain in activities of daily living and sleep was reduced by 43% (SD 37; absolute mean change 2·4 [2·3]; p=0·004) and 61% (39; absolute mean change 2·3 [1·8]; p=0·001), respectively. Two of four

Toxicology Analysis of Tissue-Mimicking Phantom Made From Gelatin

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Dolbashid, A. S.; Hamzah, N.; Zaman, W. S. W. K.; Mokhtar, M. S.

2017-06-01

Skin phantom mimics the biological skin tissues as it have the ability to respond to changes in its environment. The development of tissue-mimicking phantom could contributes towards the reduce usage of animal in cosmetics and pharmacokinetics. In this study, the skin phantoms made from gelatin were tested with four different commonly available cosmetic products to determine the toxicity of each substance. The four substances used were; mercury-based whitening face cream, carcinogenic liquid make-up foundation, paraben-based acne cleanser, and organic lip balm. Toxicity test were performed on all of the phantoms. For toxicity testing, topographical and electrophysiological changes of the phantoms were evaluated. The ability of each respective phantom to react with mild toxic substances and its electrical resistance were analysed in to determine the toxicity of all the phantom models. Four-electrode method along with custom made electrical impedance analyser was used to differentiate electrical resistance between intoxicated phantom and non-intoxicated phantom in this study. Electrical resistance values obtained from the phantom models were significantly higher than the control group. The result obtained suggests the phantom as a promising candidate to be used as alternative for toxicology testing in the future.

A Software Phantom : Application in Digital Tomosynthesis

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Lazos, D; Kolitsi, Z; Badea, C; Pallikarakis, N [Medical Physics Laboratory, School of Medicine, Univercity of Patras (Greece)

1999-12-31

A software phantom intended to be used in radiographic applications has been developed. The application was used for research in the field of Digital Tomosynthesis and specifically for studying tomographic noise removal methods. The application consists of a phantom design and a phantom imaging module. The radiation-matter interaction is based on the exponential relation of attenuation. Projections are formed by simulated irradiation with selectable geometrical parameters, source spectrum and detector response. Phantoms are defined either as sets containing certain geometrical objects or as groups of voxels. Comparison with real projections taken from a physical phantom with identical geometry and composition with the simulated one, showed good approximation with improved contrast due to the absence of scatter in the simulated projections. The software phantom proved to be a very useful tool for DTS investigations. Further development to include scatter is expected to expand the use of the application to more areas in radiological imaging research. (author) 4 refs., 3 figs

A Software Phantom : Application in Digital Tomosynthesis

International Nuclear Information System (INIS)

Lazos, D.; Kolitsi, Z.; Badea, C.; Pallikarakis, N.

1998-01-01

A software phantom intended to be used in radiographic applications has been developed. The application was used for research in the field of Digital Tomosynthesis and specifically for studying tomographic noise removal methods. The application consists of a phantom design and a phantom imaging module. The radiation-matter interaction is based on the exponential relation of attenuation. Projections are formed by simulated irradiation with selectable geometrical parameters, source spectrum and detector response. Phantoms are defined either as sets containing certain geometrical objects or as groups of voxels. Comparison with real projections taken from a physical phantom with identical geometry and composition with the simulated one, showed good approximation with improved contrast due to the absence of scatter in the simulated projections. The software phantom proved to be a very useful tool for DTS investigations. Further development to include scatter is expected to expand the use of the application to more areas in radiological imaging research. (author)

MagnetoHemoDynamics in the aorta and electrocardiograms

International Nuclear Information System (INIS)

Martin, Vincent; Drochon, Agnès; Fokapu, Odette; Gerbeau, Jean-Frédéric

2012-01-01

This paper addresses a complex multi-physical phenomenon involving cardiac electrophysiology and hemodynamics. The purpose is to model and simulate a phenomenon that has been observed in magnetic resonance imaging machines: in the presence of a strong magnetic field, the T-wave of the electrocardiogram (ECG) gets bigger, which may perturb ECG-gated imaging. This is due to a magnetohydrodynamic (MHD) effect occurring in the aorta. We reproduce this experimental observation through computer simulations on a realistic anatomy, and with a three-compartment model: inductionless MHD equations in the aorta, bi-domain equations in the heart and electrical diffusion in the rest of the body. These compartments are strongly coupled and solved using finite elements. Several benchmark tests are proposed to assess the numerical solutions and the validity of some modeling assumptions. Then, ECGs are simulated for a wide range of magnetic field intensities (from 0 to 20 T). (paper)

Ultrasonographic Quantification of Fat Content in Fatty Liver Phantoms

International Nuclear Information System (INIS)

Kim, Il Young; Kim, Pyo Nyun; Joo, Gyung Soo; Kim, Ho Jung; Kim, Young Beom; Lee, Byoung Ho

1995-01-01

Assuming that the fat content of certain tissue might be quantified by measurirrg the ultrasound echo level, we analyzed the ultrasound histograms obtained from the fatty liver phantoms that contained various amount of fat. Various amount of margarine(Mazola. Cliff wood. USA) was mixed with 2% of agarin solution state to produce fatty liver phantoms that contained 5, 10, 20, 30 and 40% of fat. We obtained ultrasound histogram from each fatty liver phantom in gel state. We used 2% agar gel as a control. The ultrasound histograms from the control phantom showed gradual increase in echo level as the depth from the surface increased. The echo level from the phantom that contained 5% of fat showed gradual increase and subsequent decrease with the peak echo level at the depth of 3cm. The echo levels from the phantoms that contained more in 5% of fat gradually decreased as the depth from the surface increased; the change becoming more pronounced as the fat content of the phantom increased. The echo levels measured at the depth of 1cm were 9.3(control), 29.6(5%phantom), 3l.3 (10% phantom), 26.3 (20% phantom), l8.8 (30% phantom), and l6dB (40% phantom). Fat content of fatty phantoms can not be quantified by measuring only echo level. Simultaneous measurement of attenuation of ultrasound, which is not easy to do and not done in this study, is prerequisite to quantify fat content

Phantom Eye Syndrome: A Review of the Literature

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Agda M. Andreotti

2014-01-01

Full Text Available The purpose of this literature review was to describe the main features of phantom eye syndrome in relation to their possible causes, symptoms, treatments, and influence of eye amputation on quality of life of anophthalmic patients. For this, a bibliographical research was performed in Pubmed database using the following terms: “eye amputation,” “eye trauma,” “phantom eye syndrome,” “phantom pain,” and “quality of life,” associated or not. Thirteen studies were selected, besides some relevant references contained in the selected manuscripts and other studies hallowed in the literature. Thus, 56 articles were included in this review. The phantom eye syndrome is defined as any sensation reported by the patient with anophthalmia, originated anophthalmic cavity. In phantom eye syndrome, at least one of these three symptoms has to be present: phantom vision, phantom pain, and phantom sensations. This syndrome has a direct influence on the quality of life of the patients, and psychological support is recommended before and after the amputation of the eyeball as well as aid in the treatment of the syndrome. Therefore, it is suggested that, for more effective treatment of phantom eye syndrome, drug therapy should be associated with psychological approach.

A phantom for quality control in mammography

International Nuclear Information System (INIS)

Gambaccini, M.; Rimondi, O.; Marziani, M.; Toti, A.

1989-01-01

A phantom for evaluating image quality in mammography has been designed and will be used in the Italian national programme ''Dose and Quality in Mammography''. The characteristics of the phantom are (a) about the same X-ray transmission as a 5 cm 50% fat and 50% water breast for energies between 15 and 50 keV and (b) optimum energies for imaging of the test objects (included in the phantom) in very close agreement with the optimum energies for imaging of calcifications and tumours in a 5 cm 50% fat and 50% water breast. An experimental comparison between the prototype and some commercial phantoms was carried out. Measurements are in progress to test the phantom's ability to evaluate the performances of mammographic systems quantitatively. (author)

Two-stage multilevel en bloc spondylectomy with resection and replacement of the aorta.

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Gösling, Thomas; Pichlmaier, Maximilian A; Länger, Florian; Krettek, Christian; Hüfner, Tobias

2013-05-01

We report a case of multilevel spondylectomy in which resection and replacement of the adjacent aorta were done. Although spondylectomy is nowadays an established technique, no report on a combined aortic resection and replacement has been reported so far. The case of a 43-year-old man with a primary chondrosarcoma of the thoracic spine is presented. The local pathology necessitated resection of the aorta. We did a two-stage procedure with resection and replacement of the aorta using a heart-lung machine followed by secondary tumor resection and spinal reconstruction. The procedure was successful. A tumor-free margin was achieved. The patient is free of disease 48 months after surgery. En bloc spondylectomy in combination with aortic resection is feasible and might expand the possibility of producing tumor-free margins in special situations.

CD45{sup low}c-Kit{sup high} cells have hematopoietic properties in the mouse aorta-gonad-mesonephros region

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Nobuhisa, Ikuo, E-mail: nobuhisa.scr@mri.tmd.ac.jp [Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510 (Japan); Department of Cell Fate Modulation, Institute of Molecular Embryology and Genetics/Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 860-0811 (Japan); Yamasaki, Shoutarou [Department of Cell Fate Modulation, Institute of Molecular Embryology and Genetics/Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 860-0811 (Japan); Ramadan, Ahmed [Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510 (Japan); Department of Cell Fate Modulation, Institute of Molecular Embryology and Genetics/Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 860-0811 (Japan); Taga, Tetsuya, E-mail: taga.scr@mri.tmd.ac.jp [Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510 (Japan); Department of Cell Fate Modulation, Institute of Molecular Embryology and Genetics/Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 860-0811 (Japan)

2012-04-01

Long-term reconstituting hematopoietic stem cells first arise from the aorta of the aorta-gonad-mesonephros (AGM) region in a mouse embryo. We have previously reported that in cultures of the dispersed AGM region, CD45{sup low}c-Kit{sup +} cells possess the ability to reconstitute multilineage hematopoietic cells, but investigations are needed to show that this is not a cultured artifact and to clarify when and how this population is present. Based on the expression profile of CD45 and c-Kit in freshly dissociated AGM cells from embryonic day 9.5 (E9.5) to E12.5 and aorta cells in the AGM from E13.5 to E15.5, we defined six cell populations (CD45{sup -}c-Kit{sup -}, CD45{sup -}c-Kit{sup low}, CD45{sup -}c-Kit{sup high}, CD45{sup low}c-Kit{sup high}, CD45{sup high}c-Kit{sup high}, and CD45{sup high}c-Kit{sup very} {sup low}). Among these six populations, CD45{sup low}c-Kit{sup high} cells were most able to form hematopoietic cell colonies, but their ability decreased after E11.5 and was undetectable at E13.5 and later. The CD45{sup low}c-Kit{sup high} cells showed multipotency in vitro. We demonstrated further enrichment of hematopoietic activity in the Hoechst dye-effluxing side population among the CD45{sup low}c-Kit{sup high} cells. Here, we determined that CD45{sup low}c-Kit{sup high} cells arise from the lateral plate mesoderm using embryonic stem cell-derived differentiation system. In conclusion, CD45{sup low}c-Kit{sup high} cells are the major hematopoietic cells of mouse AGM.

Uric acid does not affect the acetylcholine-induced relaxation of aorta from normotensive and deoxycorticosterone acetate-salt hypertensive rats.

Science.gov (United States)

Szasz, Theodora; Watts, Stephanie W

2010-06-01

Uric acid (UA) results from xanthine oxidase (XO) catabolism of xanthine and is the final product of purine catabolism in humans. In this species, hyperuricemia is associated with gout, nephropathy, and increased cardiovascular disease risk. Although the effects of hyperuricemia in vascular biology are overall controversial, UA has been described as an antioxidant and as potentially improving endothelial function. Hypertension is associated with endothelial dysfunction. We hypothesized that UA improves the endothelial function of aorta from deoxycorticosterone acetate (DOCA)-salt hypertensive rats. UA (100 microM) in the presence of the uricase inhibitor oxonic acid (10 microM) did not modify relaxation to acetylcholine (ACh) (1 nM-10 microM) in the aorta from nontreated, sham normotensive, and DOCA-salt hypertensive rats [response to 10 microM ACh for UA versus vehicle, respectively: nontreated = 37 +/- 7 versus 48 +/- 7%, sham = 53 +/- 15 versus 57 +/- 20%, DOCA = 81 +/- 4 versus 85 +/- 2% from 20 microM prostaglandin 2alpha (PGF(2alpha))-induced contraction]. Allopurinol (100 microM), a XO inhibitor, did not significantly alter the ACh-induced relaxation of sham and DOCA aortic rings (response to 10 microM ACh for allopurinol versus vehicle, respectively: sham = 61 +/- 5 versus 68 +/- 9%, DOCA = 87 +/- 6 versus 88 +/- 3% from 20 microM PGF(2alpha)-induced contraction). Uricemia, ranging from unmeasurable to 547 microM in sham and to 506 microM in DOCA rats, was not significantly different between these two groups. The expression and activity of XO, as well as the expression of uricase, were not different between sham and DOCA rat aorta. We conclude that, at least in vitro, UA does not affect the ACh-induced relaxation of normotensive and DOCA-salt hypertensive rats.

Phantom cosmology without Big Rip singularity

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Astashenok, Artyom V. [Baltic Federal University of I. Kant, Department of Theoretical Physics, 236041, 14, Nevsky st., Kaliningrad (Russian Federation); Nojiri, Shin' ichi, E-mail: nojiri@phys.nagoya-u.ac.jp [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya 464-8602 (Japan); Odintsov, Sergei D. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Institucio Catalana de Recerca i Estudis Avancats - ICREA and Institut de Ciencies de l' Espai (IEEC-CSIC), Campus UAB, Facultat de Ciencies, Torre C5-Par-2a pl, E-08193 Bellaterra (Barcelona) (Spain); Tomsk State Pedagogical University, Tomsk (Russian Federation); Yurov, Artyom V. [Baltic Federal University of I. Kant, Department of Theoretical Physics, 236041, 14, Nevsky st., Kaliningrad (Russian Federation)

2012-03-23

We construct phantom energy models with the equation of state parameter w which is less than -1, w<-1, but finite-time future singularity does not occur. Such models can be divided into two classes: (i) energy density increases with time ('phantom energy' without 'Big Rip' singularity) and (ii) energy density tends to constant value with time ('cosmological constant' with asymptotically de Sitter evolution). The disintegration of bound structure is confirmed in Little Rip cosmology. Surprisingly, we find that such disintegration (on example of Sun-Earth system) may occur even in asymptotically de Sitter phantom universe consistent with observational data. We also demonstrate that non-singular phantom models admit wormhole solutions as well as possibility of Big Trip via wormholes.

Phantom cosmology without Big Rip singularity

International Nuclear Information System (INIS)

Astashenok, Artyom V.; Nojiri, Shin'ichi; Odintsov, Sergei D.; Yurov, Artyom V.

2012-01-01

We construct phantom energy models with the equation of state parameter w which is less than -1, w<-1, but finite-time future singularity does not occur. Such models can be divided into two classes: (i) energy density increases with time (“phantom energy” without “Big Rip” singularity) and (ii) energy density tends to constant value with time (“cosmological constant” with asymptotically de Sitter evolution). The disintegration of bound structure is confirmed in Little Rip cosmology. Surprisingly, we find that such disintegration (on example of Sun-Earth system) may occur even in asymptotically de Sitter phantom universe consistent with observational data. We also demonstrate that non-singular phantom models admit wormhole solutions as well as possibility of Big Trip via wormholes.

Medical image of the week: atherosclerotic aneurysm of aortic arch and descecnding 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 ...

Dissection of descending aorta treated by stent-graft implantation in a patient with Marfan syndrome

Directory of Open Access Journals (Sweden)

Marat A. Aripov

2017-04-01

Full Text Available This report describes a 32 years old patient with Marfan syndrome and hypertension. David`s procedure was performed to the patient three months before due to dissection of the ascending thoracic aorta. Computer tomography scan showed DeBakey type III dissection of aorta beginning from left subclavian artery with transition to the ostium of the celiac trunk and proximal part of the left common iliac artery. Stent-grafts in the descending thoracic aorta with overlapping of left subclavian artery were implanted to the patient with Marfan syndrome. Patient was discharged and no complications recorded at 6th month follow-up.

High-pitch dual-source CT angiography of the whole aorta without ECG synchronisation: Initial experience

International Nuclear Information System (INIS)

Beeres, Martin; Schell, Boris; Mastragelopoulos, Aristidis; Kerl, Josef Matthias; Gruber-Rouh, Tatjana; Lee, Clara; Siebenhandl, Petra; Bodelle, Boris; Zangos, Stephan; Vogl, Thomas J.; Jacobi, Volkmar; Bauer, Ralf W.; Herrmann, Eva

2012-01-01

To investigate the feasibility, image quality and radiation dose for high-pitch dual-source CT angiography (CTA) of the whole aorta without ECG synchronisation. Each group of 40 patients underwent CTA either on a 16-slice (group 1) or dual-source CT device with conventional single-source (group 2) or high-pitch mode with a pitch of 3.0 (group 3). The presence of motion or stair-step artefacts of the thoracic aorta was independently assessed by two readers. Subjective and objective scoring of motion and artefacts were significantly reduced in the high-pitch examination protocol (p < 0.05). The imaging length was not significantly different, but the imaging time was significantly (p < 0.001) shorter in the high-pitch group (12.2 vs. 7.4 vs. 1.7 s for groups 1, 2 and 3). The ascending aorta and the coronary ostia were reliably evaluable in all patients of group 3 without motion artefacts as well. High-pitch dual-source CT angiography of the whole aorta is feasible in unselected patients. As a significant advantage over regular pitch protocols, motion-free imaging of the aorta is possible without ECG synchronisation. Thus, this CT mode bears potential to become a standard CT protocol before trans-catheter aortic valve implantation (TAVI). (orig.)

Development of digital phantom for DRR evaluation

International Nuclear Information System (INIS)

Ikeda, Tsuyoshi; Katsuta, Shoichi; Oyama, Masaya; Ogino, Takashi

2009-01-01

Generally, digitally reconstructed radiograph (DRR) is evaluated by physical phantom. The CT image is camouflaged by the performance of the radiation treatment planning system and contains a variety of error factors. The CT image (as follows the digital phantom), where an arbitrary CT value is arranged in the matrix, is necessary to evaluate the pure performance of the radiation treatment planning system. In this study, the development of a digital phantom is described, and the utility is discussed. CTport and the radiation treatment planning system are evaluated with the use of a digital phantom as follows: geometrical accuracy evaluation of DRR, consisting of the center position, size of irradiation field, distortion, extension of X-ray, and beam axis, and the image quality evaluation of DRR, which consists of the contrast resolution. As for DRR made with CTport and the treatment planning system, the part that shifted geometrically was confirmed. In the image quality evaluation, there was a remarkable difference. Because the making accuracy and the installation accuracy of the phantom do not influence the digital phantom, the geometrical accuracy of the DRR is reliable. Because the CT conditions and the phantom factor have no influence, the peculiar DRR image quality can be evaluated and used to evaluate the best image processing parameters. (author)

Low-level 45,X/46,XX mosaicism is not associated with congenital heart disease and thoracic aorta dilatation:prospective magnetic resonance imaging and ultrasound study.

Science.gov (United States)

Klásková, E; Tüdös, Z; Sobek, A; Zapletalová, J; Dostál, J; Zbořilová, B; Sobek, A; Adamová, K; Lattová, V; Dostálová, Z; Procházka, M

2015-06-01

To establish the prevalence of risk factors for aortic dissection, such as bicuspid aortic valve, aortic coarctation and ascending aorta dilatation, in women with low-level 45,X/46,XX mosaicism undergoing an in-vitro fertilization (IVF) procedure. The study group comprised 25 women with low-level 45,X/46,XX mosaicism (ranging from 3.3% to 10.0%) who were referred to two reproductive medicine units between 2009 and 2013 because of infertility and who underwent subsequent karyotyping. In accordance with the recommendation of the Practice Committee of the American Society for Reproductive Medicine for patients with Turner syndrome (TS), prior to the IVF procedure, all women underwent careful cardiovascular screening for congenital heart disease and thoracic aorta dilatation, including standard cardiac examination, echocardiography and non-contrast cardiac magnetic resonance imaging. Aortic size index (ASI, diameter of the ascending aorta normalized to body surface area) and the prevalence of coarctation of the aorta and of bicuspid aortic valve were compared with findings previously reported in women with TS and the general population. Bicuspid aortic valve without any stenosis or regurgitation was found in one woman in the study group with low-level 45,X/46,XX mosaicism, a statistically significantly lower prevalence of bicuspid aortic valve than that reported in women with TS. Aortic coarctation was not identified in any individual. The ASI was below the  95th percentile in all cases and the mean value was significantly lower than the mean reference values for both the general population and women with TS. Compared with the general population, the prevalence of risk factors for aortic dissection was not found to be higher in women with low-level 45,X/46,XX mosaicism without any noticeable features except infertility. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

Estimation of prenatal aorta intima-media thickness from ultrasound examination

International Nuclear Information System (INIS)

Veronese, E; Tarroni, G; Grisan, E; Visentin, S; Cosmi, E; Linguraru, M G

2014-01-01

Prenatal events such as intrauterine growth restriction and increased cardiovascular risk in later life have been shown to be associated with an increased intima-media thickness (aIMT) of the abdominal aorta in the fetus. In order to assess and manage atherosclerosis and cardiovascular disease risk in adults and children, in recent years the measurement of abdominal and carotid artery thickness has gained a growing appeal. Nevertheless, no computer aided method has been proposed for the analysis of prenatal vessels from ultrasound data, yet. To date, these measurements are being performed manually on ultrasound fetal images by skilled practitioners. The aim of the presented study is to introduce an automatic algorithm that identifies abdominal aorta and estimates its diameter and aIMT from routine third trimester ultrasonographic fetal data. The algorithm locates the aorta, then segments it and, by modeling the arterial wall longitudinal sections by means of a gaussian mixture, derives a set of measures of the aorta diameter (aDiam) and of the intima-media thickness (aIMT). After estimating the cardiac cycle, the mean diameter and the aIMT at the end-diastole phase are computed. Considering the aIMT value for each subject, the correlation between automatic and manual end-diastolic aIMT measurements is 0.91 in a range of values 0.44-1.10 mm, corresponding to both normal and pathological conditions. The automatic system yields a mean relative error of 19%, that is similar to the intra-observer variability (14%) and much lower that the inter-observer variability (42%). The correlation between manual and automatic measurements and the small error confirm the ability of the proposed system to reliably estimate aIMT values in prenatal ultrasound sequences, reducing measurement variability and suggesting that it can be used for an automatic assessment of aIMT. (paper)

Acute intramural hematoma of ascending aorta. CT findings and clinical outcome

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Yamaguchi, Toshio; Sakuyama, Keiko; Hiekata, Tomizou; Yamanaka, Ikuo [St. Marianna Univ., Kanagawa (Japan). Yokohama Seibu Hospital; Kuroki, Kazunori; Ohyama, Yukio; Ishikawa, Tohru; Kawada, Tadanori; Akashi, Katsuya

1997-12-01

The purpose of this study was to describe the CT findings and clinical outcomes of nineteen patients with acute intramural hematoma (IMH) of the ascending aorta. Six patients underwent surgery on the emergency basis (3 patients) due to cardiac tamponade (n=2) and dilated aorta (n=1), and on the elective basis (3 patients) due to patent and enlarging false lumen. Among the 13 patients with medical management, four patients died from complications of IMH during the follow-up period (2 days-2.5 years). Transition to aortic dissection or enlargement of an intimal tear was noted in 5 patients (31%) in 1 to 6 weeks after onset. Three patients died of causes not related to IMH. Six patients had been alive 2 to 9 years after onset. Retrospective review revealed 10 patients (53%) as possible surgical candidates, and the other 9 patients as medically treated patients in the long-term follow-up. The surgical group showed cardiac tamponade or shock in 6 patients on admission and had pericardial effusion in all the patients on the initial CT scan. In the patients with acute IMH of the ascending aorta, surgery should be considered for severe clinical symptoms, pericardial effusion and large size of the ascending aorta (more than 4 cm) on CT scan, and for converting to a typical type A aortic dissection. CT scan had a major role in making an early diagnosis, in depicting a dangerous sign, and in monitoring its progression or resolution of IMH. (author)

Mechanical contribution of lamellar and interlamellar elastin along the mouse aorta.

Science.gov (United States)

Clark, T E; Lillie, M A; Vogl, A W; Gosline, J M; Shadwick, R E

2015-10-15

The mechanical properties of aortic elastin vary regionally, but the microstructural basis for this variation is unknown. This study was designed to identify the relative contributions of lamellar and interlamellar elastin to circumferential load bearing in the mouse thoracic and abdominal aortas. Forces developed in uniaxial tests of samples of fresh and autoclaved aorta were correlated with elastin content and morphology obtained from histology and multiphoton laser scanning microscopy. Autoclaving should render much of the interlamellar elastin mechanically incompetent. In autoclaved tissue force per unit sample width correlated with lamellar elastin content (P≪0.001) but not total elastin content. In fresh tissue at low strain where elastin dominates the mechanical response, forces were higher than in the autoclaved tissue, but force did not correlate with total elastin content. Therefore although interlamellar elastin likely contributed to the stiffness in the fresh aorta, its contribution appeared not in proportion to its quantity. In both fresh and autoclaved tissue, elastin stiffness consistently decreased along the abdominal aorta, a key area for aneurysm development, and this difference could not be fully accounted for on the basis of either lamellar or total elastin content. These findings are relevant to the development of mathematical models of arterial mechanics, particularly for mouse models of arterial diseases involving elastic tissue. In microstructural based models the quantity of each mural constituent determines its contribution to the total response. This study shows elastin's mechanical response cannot necessarily be accounted for on the basis of fibre quantity, orientation, and modulus. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of the Reference Korean Female Voxel Phantom

International Nuclear Information System (INIS)

Ham, Bo Kyoung; Cho, Kun Woo; Yeom, Yoen Soo; Jeong, Jong Hwi; Kim, Chan Hyeong; Han, Min Cheol

2012-01-01

The objective of this study is for development of the reference Korean female phantom, HDRK-Woman. The phantom was constructed by adjusting a Korean woman voxel phantom to the Reference Korean data. The Korean woman phantom had been developed based on the high-resolution color slice images obtained from an adult Korean female cadaver. There were a total of 39 organs including the 27 organs specified in ICRP 103 for effective dose calculation. The voxel resolution of the phantom was 1.967 X 1.967 X X 2.0619 mm 3 and the voxel array size is 261 X 109 X 825 in the x, y and z directions. Then, the voxel resolution was changed to 2.0351 X 2.0351 X 2.0747 mm 3 for adjustment of the height and total bone mass of the phantom to the Reference Korean data. Finally, the internal organs and tissue were adjusted using in-house software program developed for 3D volume adjustment of the organs and tissue. The effective dose values of HDRK phantoms were calculated for broad parallel photon beams using MCNPX Monte Carlo code and compared with those of ICRP phantoms.

Development of the Reference Korean Female Voxel Phantom

Energy Technology Data Exchange (ETDEWEB)

Ham, Bo Kyoung; Cho, Kun Woo [University of Science and Technology, Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Yeom, Yoen Soo; Jeong, Jong Hwi; Kim, Chan Hyeong; Han, Min Cheol [Hanyang University, Seoul (Korea, Republic of)

2012-03-15

The objective of this study is for development of the reference Korean female phantom, HDRK-Woman. The phantom was constructed by adjusting a Korean woman voxel phantom to the Reference Korean data. The Korean woman phantom had been developed based on the high-resolution color slice images obtained from an adult Korean female cadaver. There were a total of 39 organs including the 27 organs specified in ICRP 103 for effective dose calculation. The voxel resolution of the phantom was 1.967 X 1.967 X X 2.0619 mm{sup 3} and the voxel array size is 261 X 109 X 825 in the x, y and z directions. Then, the voxel resolution was changed to 2.0351 X 2.0351 X 2.0747 mm{sup 3} for adjustment of the height and total bone mass of the phantom to the Reference Korean data. Finally, the internal organs and tissue were adjusted using in-house software program developed for 3D volume adjustment of the organs and tissue. The effective dose values of HDRK phantoms were calculated for broad parallel photon beams using MCNPX Monte Carlo code and compared with those of ICRP phantoms.

Development of a physical 3D anthropomorphic breast phantom

Energy Technology Data Exchange (ETDEWEB)

Carton, Ann-Katherine; Bakic, Predrag; Ullberg, Christer; Derand, Helen; Maidment, Andrew D. A. [Department of Radiology, University of Pennsylvania, 1 Silverstein Building, 3400 Spruce Street, Philadelphia, Pennsylvania 19104-4206 (United States); XCounter AB, Svaerdvaegen 11, SE-182 33 Danderyd (Sweden); Department of Radiology, University of Pennsylvania, 1 Silverstein Building, 3400 Spruce Street, Philadelphia, Pennsylvania 19104-4206 (United States)

2011-02-15

Purpose: Develop a technique to fabricate a 3D anthropomorphic breast phantom with known ground truth for image quality assessment of 2D and 3D breast x-ray imaging systems. Methods: The phantom design is based on an existing computer model that can generate breast voxel phantoms of varying composition, size, and shape. The physical phantom is produced in two steps. First, the portion of the voxel phantom consisting of the glandular tissue, skin, and Cooper's ligaments is separated into sections. These sections are then fabricated by high-resolution rapid prototyping using a single material with 50% glandular equivalence. The remaining adipose compartments are then filled using an epoxy-based resin (EBR) with 100% adipose equivalence. The phantom sections are stacked to form the physical anthropomorphic phantom. Results: The authors fabricated a prototype phantom corresponding to a 450 ml breast with 45% dense tissue, deformed to a 5 cm compressed thickness. Both the rapid prototype (RP) and EBR phantom materials are radiographically uniform. The coefficient of variation (CoV) of the relative attenuation between RP and EBR phantom samples was <1% and the CoV of the signal intensity within RP and EBR phantom samples was <1.5% on average. Digital mammography and reconstructed digital breast tomosynthesis images of the authors' phantom were reviewed by two radiologists; they reported that the images are similar in appearance to clinical images, noting there are still artifacts from air bubbles in the EBR. Conclusions: The authors have developed a technique to produce 3D anthropomorphic breast phantoms with known ground truth, yielding highly realistic x-ray images. Such phantoms may serve both qualitative and quantitative performance assessments for 2D and 3D breast x-ray imaging systems.

Computational anthropomorphic phantoms for radiation protection dosimetry: evolution and prospects

International Nuclear Information System (INIS)

Lee, Choonsik; Lee, Jaiki

2006-01-01

Computational anthropomorphic phantoms are computer models of human anatomy used in the calculation of radiation dose distribution in the human body upon exposure to a radiation source. Depending on the manner to represent human anatomy, they are categorized into two classes: stylized and tomographic phantoms. Stylized phantoms, which have mainly been developed at the Oak Ridge National Laboratory (ORNL), describe human anatomy by using simple mathematical equations of analytical geometry. Several improved stylized phantoms such as male and female adults, pediatric series, and enhanced organ models have been developed following the first hermaphrodite adult stylized phantom, Medical Internal Radiation Dose (MIRD)-5 phantom. Although stylized phantoms have significantly contributed to dosimetry calculation, they provide only approximations of the true anatomical features of the human body and the resulting organ dose distribution. An alternative class of computational phantom, the tomographic phantom, is based upon three-dimensional imaging techniques such as Magnetic Resonance (MR) imaging and Computed Tomography (CT). The tomographic phantoms represent the human anatomy with a large number of voxels that are assigned tissue type and organ identity. To date, a total of around 30 tomographic phantoms including male and female adults, pediatric phantoms, and even a pregnant female, have been developed and utilized for realistic radiation dosimetry calculation. They are based on MRI/CT images or sectional color photos from patients, volunteers or cadavers. Several investigators have compared tomographic phantoms with stylized phantoms, and demonstrated the superiority of tomographic phantoms in terms of realistic anatomy and dosimetry calculation. This paper summarizes the history and current status of both stylized and tomographic phantoms, including Korean computational phantoms. Advantages, limitations, and future prospects are also discussed

WE-D-303-00: Computational Phantoms

Energy Technology Data Exchange (ETDEWEB)

Lewis, John [Duke University Medical Center, Durham, NC (United States); Brigham and Women’s Hospital and Dana-Farber Cancer Institute, Boston, MA (United States)

2015-06-15

Modern medical physics deals with complex problems such as 4D radiation therapy and imaging quality optimization. Such problems involve a large number of radiological parameters, and anatomical and physiological breathing patterns. A major challenge is how to develop, test, evaluate and compare various new imaging and treatment techniques, which often involves testing over a large range of radiological parameters as well as varying patient anatomies and motions. It would be extremely challenging, if not impossible, both ethically and practically, to test every combination of parameters and every task on every type of patient under clinical conditions. Computer-based simulation using computational phantoms offers a practical technique with which to evaluate, optimize, and compare imaging technologies and methods. Within simulation, the computerized phantom provides a virtual model of the patient’s anatomy and physiology. Imaging data can be generated from it as if it was a live patient using accurate models of the physics of the imaging and treatment process. With sophisticated simulation algorithms, it is possible to perform virtual experiments entirely on the computer. By serving as virtual patients, computational phantoms hold great promise in solving some of the most complex problems in modern medical physics. In this proposed symposium, we will present the history and recent developments of computational phantom models, share experiences in their application to advanced imaging and radiation applications, and discuss their promises and limitations. Learning Objectives: Understand the need and requirements of computational phantoms in medical physics research Discuss the developments and applications of computational phantoms Know the promises and limitations of computational phantoms in solving complex problems.

WE-D-303-00: Computational Phantoms

International Nuclear Information System (INIS)

Lewis, John

2015-01-01

Modern medical physics deals with complex problems such as 4D radiation therapy and imaging quality optimization. Such problems involve a large number of radiological parameters, and anatomical and physiological breathing patterns. A major challenge is how to develop, test, evaluate and compare various new imaging and treatment techniques, which often involves testing over a large range of radiological parameters as well as varying patient anatomies and motions. It would be extremely challenging, if not impossible, both ethically and practically, to test every combination of parameters and every task on every type of patient under clinical conditions. Computer-based simulation using computational phantoms offers a practical technique with which to evaluate, optimize, and compare imaging technologies and methods. Within simulation, the computerized phantom provides a virtual model of the patient’s anatomy and physiology. Imaging data can be generated from it as if it was a live patient using accurate models of the physics of the imaging and treatment process. With sophisticated simulation algorithms, it is possible to perform virtual experiments entirely on the computer. By serving as virtual patients, computational phantoms hold great promise in solving some of the most complex problems in modern medical physics. In this proposed symposium, we will present the history and recent developments of computational phantom models, share experiences in their application to advanced imaging and radiation applications, and discuss their promises and limitations. Learning Objectives: Understand the need and requirements of computational phantoms in medical physics research Discuss the developments and applications of computational phantoms Know the promises and limitations of computational phantoms in solving complex problems

Tratamiento de aorta abdominal e ilíacas con técnica endovascular: Experiencia quirúrgica Treatment of abdominal aorta and iliac arteries with endovascular technique

Directory of Open Access Journals (Sweden)

Juan G Barrera

2007-08-01

Full Text Available Antecedentes: desde 1991 la técnica endovascular se ha aplicado con éxito en el manejo de los aneurismas de aorta infrarrenal, y se ha perfeccionado de manera tal que rápidamente se ha convertido en una alternativa para pacientes de alto riesgo para la cirugía convencional. Objetivo: describir los resultados institucionales en el manejo de las patologías de aorta abdominal e ilíacas mediante técnica endovascular desde 2003 a 2005. Diseño-Método: estudio descriptivo, longitudinal, retrospectivo, en el que se analizaron las historias clínicas de los pacientes sometidos a procedimiento endovascular de aorta abdominal e ilíacas. El análisis se realizó en Stata 8,0 S/E. Resultados: a 9 pacientes se les realizó exclusivamente manejo de lesiones en aorta abdominal e ilíacas. Todos los pacientes del estudio fueron hombres con edad media de 68,9 + 8,1 años. Los diagnósticos fueron aneurisma de aorta infrarrenal en 6 pacientes y aneurismas anastomóticos en los 3 restantes. Se evidenció requerimiento de endoprótesis en promedio de 1,9 + 0,8. Se realizó puente femoro-femoral como procedimiento simultáneo en 4 de los 9 pacientes. El 77,8% de los pacientes no tuvo complicaciones. La mortalidad por el procedimiento alcanzó el 22% (2 pacientes, si bien cabe anotar que las complicaciones se presentaron sólo en esos dos pacientes. Conclusiones: la exclusión de aneurismas de aorta y de ilíacas con endoprótesis modulares, se está implementando ampliamente como una opción válida de tratamiento, con resultados excelentes que evitan los riesgos de la intervención convencional y la morbilidad asociada.Antecedents: since 1991 endovascular technique has been successfully used in the management of infra-renal aortic aneurysms and it has been improved in such a way that it has quickly turned into an alternative for patients considered having high risk for conventional surgery. Objective: describe the institutional results in the management of

Coarctation of the aorta and renal artery stenosis in tuberous sclerosis

Energy Technology Data Exchange (ETDEWEB)

Flynn, P M; Robinson, M B; Stapleton, F B; Roy, S III; Koh, G; Tonkin, I L.D.

1984-07-01

Among neurocutaneous disorders, coarctation of the abdominal aorta and renal artery stenosis have traditionally been associated with neurofibromatosis. We report a 5-year-old girl who was discovered to have bilateral renal artery stenosis, coarctation of the abdominal aorta, renal cysts and typical skin lesions of tuberous clerosis during the evaluation of asymptomatic hypertension. Renal vascular hypertension has not been reported previously in tuberous sclerosis. We conclude that the tuberous sclerosis complex should be expanded to include vascular malformations and the hypertension should not be assumed to be secondary to renal hamartomata or cysts in patients with tuberous sclerosis.

Coarctation of the aorta and renal artery stenosis in tuberous sclerosis

International Nuclear Information System (INIS)

Flynn, P.M.; Robinson, M.B.; Stapleton, F.B.; Roy, S. III; Koh, G.; Tonkin, I.L.D.; Tennessee Univ., Memphis; Tennessee Univ., Memphis; LeBonheur Children's Medical Center, Memphis, TN

1984-01-01

Among neurocutaneous disorders, coarctation of the abdominal aorta and renal artery stenosis have traditionally been associated with neurofibromatosis. We report a 5-year-old girl who was discovered to have bilateral renal artery stenosis, coarctation of the abdominal aorta, renal cysts and typical skin lesions of tuberous clerosis during the evaluation of asymptomatic hypertension. Renal vascular hypertension has not been reported previously in tuberous sclerosis. We conclude that the tuberous sclerosis complex should be expanded to include vascular malformations and the hypertension should not be assumed to be secondary to renal hamartomata or cysts in patients with tuberous sclerosis. (orig.)

Extra-Anatomic Revascularization of Extensive Coral Reef Aorta.

Science.gov (United States)

Gaggiano, Andrea; Kasemi, Holta; Monti, Andrea; Laurito, Antonella; Maselli, Mauro; Manzo, Paola; Quaglino, Simone; Tavolini, Valeria

2017-10-01

Coral reef aorta (CRA) is a rare, potential lethal disease of the visceral aorta as it can cause visceral and renal infarction. Various surgical approaches have been proposed for the CRA treatment. The purpose of this article is to report different extensive extra-anatomic CRA treatment modalities tailored on the patients' clinical and anatomic presentation. From April 2006 to October 2012, 4 symptomatic patients with extensive CRA were treated at our department. Extra-anatomic aortic revascularization with selective visceral vessels clamping was performed in all cases. Technical success was 100%. No perioperative death was registered. All patients remained asymptomatic during the follow-up period (62, 49, 25, and 94 months, respectively), with bypasses and target vessels patency. The extra-anatomic bypass with selective visceral vessels clamping reduces the aortic occlusion time and the risk of organ ischemia. All approaches available should be considered on a case-by-case basis and in high-volume centers. Copyright © 2017 Elsevier Inc. All rights reserved.

[Mirror, mirror of the wall: mirror therapy in the treatment of phantom limbs and phantom limb pain].

Science.gov (United States)

Casale, Roberto; Furnari, Anna; Lamberti, Raul Coelho; Kouloulas, Efthimios; Hagenberg, Annegret; Mallik, Maryam

2015-01-01

Phantom limb and phantom limb pain control are pivotal points in the sequence of intervention to bring the amputee to functional autonomy. The alterations of perception and sensation, the pain of the residual limb and the phantom limb are therefore aspects of amputation that should be taken into account in the "prise en charge" of these patients. Within the more advanced physical therapies to control phantom and phantom limb pain there is the use of mirrors (mirror therapy). This article willfocus on its use and on the possible side effects induced by the lack of patient selection and a conflict of body schema restoration through mirror therapy with concurrent prosthetic training and trauma acceptance. Advice on the need to select patients before treatment decisions, with regard to their psychological as well as clinical profile (including time since amputation and clinical setting), and the need to be aware of the possible adverse effects matching different and somehow conflicting therapeutic approaches, are put forward. Thus a coordinated sequence of diagnostic, prognostic and therapeutic procedures carried out by an interdisciplinary rehabilitation team that works globally on all patients' problems is fundamental in the management of amputees and phantom limb pain. Further studies and the development of a multidisciplinary network to study this and other applications of mirror therapy are needed.

Contrast detail phantom for SPECT

Energy Technology Data Exchange (ETDEWEB)

Cabrejas, M.L. de; Arashiro, J G; Giannone, C. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Camuyrano, M; Nohara, G [Universidad de Buenos Aires, Buenos Aires (Argentina). Facultad Ciencias Exactas

1996-06-01

A new low variable contrast phantom for single photon emission computed tomography (SPECT) was constructed, tested and compared with other existing phantoms. It contains simulated cylindrical lesions of four different diameters (D{sub i}), embedded in a cylindrical scattering medium and a uniform section to evaluate tomographic uniformity. The concentration of tracer in the simulated lesions and the scattering medium (background) can be varied to simulate hot and cold lesions. Different applications of the phantom were tested, including determination of the minimum object contrast (OCm) necessary to detect lesions as a function of lesion size, lesion type (hot or cold) and acquisition and processing protocols by visual inspection. This parameter allows categorization of instruments comparing an `image quality index` (IQI). Preliminary comparison with the Britten contrast processing method showed that the detectable OCm was of the same order of magnitude, but the presented device seems more suitable for training and intercomparison purposes. The constructed phantom, of simple design, has proved to be useful for acquisition and processing condition evaluation, OCm estimation and external quality control. (author). 11 refs, 4 figs.

In-vitro studies of change in edge detection with changes in bone density

International Nuclear Information System (INIS)

Pocock, N.; Noakes, K.; Griffiths, M.

1999-01-01

Full text: Dual energy X-ray absorptiometry (DXA) requires edge detection software to identify the skeletal regions for quantitation of bone mineral density (BMD) and bone mineral content (BMC). As bone mass decreases, the detection of bone edges becomes more difficult and this potentially could cause errors in DXA estimations of areal BMD or BMC. To address this issue, we have used an in-vitro model to study the effects of 'bone loss' on calculated bone area, BMD and BMC. Multiple vertebral phantoms, of equal cross-sectional area but incrementally decreased areal BMD, were constructed using calcium sulphate hemihydrate. The weight of each phantom vertebra, measured accurately using an electronic balance, was used as an index of its true 'bone mass equivalent' (BME). The phantoms were scanned and analysed in the lumbar spine mode using a Lunar DPX-L (L) and Hologic QDR-1000 (H). The changes in BME were compared to changes in measured area, BMC and areal BMD. The results demonstrate that, in an in-vitro model, as bone mass decreases, measured bone area and consequently BMC will decrease as the edge detection algorithms have greater difficulty in detecting the true edges. In conclusion, in an in-vitro model, the DXA edge detection algorithms will underestimate bone area as bone mass decreases. This has potential implications for monitoring changes in bone mass in vivo

Plaque of atherosclerosis in aorta: review on atherogenesis, formation of plaque, clinical significance, methods of imaging and treatment; Placa de aterosclerose em aorta: revisao sobre aterogenese, formacao de placa, significado clinco, metodos de imagens e tratamento

Energy Technology Data Exchange (ETDEWEB)

Furtado, Rogerio Gomes; Nunes, Colandy G. de Oliveira; Rassi, Junior, Luis; Melato, Luciano Henrique; Turco, Fabio de Paula; Borges, Moises Marcos, E-mail: rogerinhofurtado@gmail.com [Centro de Diagnostico por Imagem (CDI), Goiania, GO (Brazil); Sara, Leonardo [Instituto do Coracao (InCor/FM/USP), Sao Paulo, SP (Brazil)

2009-04-15

There is a certain consensus in the literature that the earliest stage of atherogenesis is characterized by the accumulation of spongy cells in the region of the intimal artery. Risk factors such as arterial hypertension, smoking, diabetes mellitus, hypercholesterolemia, male gender and advanced age predispose a person to the formation of plaques in the coronaries and aorta. A greater number of acute coronary events as well as strokes have been observed in people with these risk factors. Strokes are the third cause of death in the USA, with about 40% of the cases being of cryptogenic origin. Since 1989 the atheroma plaques which develop in the thoracic aorta have been considered to be responsible for cerebral and peripheral strokes which were previously considered cryptogenic because imaging techniques such as electrocardiogram transesophageal, computerized tomogram, nuclear magnetic angio-resonance have visualized and characterized the lesions with plaques of arteriosclerosis in the thoracic aorta. The authors of this article made a systematic review in the PUBMED about arteriosclerosis in the aorta and its diagnostic methods. This review includes the physiopathology of the formation of atheroma to the aorta and its consequences, diagnostic methods such as echo transesophageal, computerized tomogram and angio resonance, as well as the advantages and disadvantages of each method of identification of the lesions. An analysis of the clinical significance of the size, form and location of the atheroma plaques in the thoracic aorta were made based on clinical studies, as well as their treatment with anticoagulants, antiplatelet and drugs to reduce cholesterol. (author)

The AORTA Architecture: Integrating Organizational Reasoning in Jason

DEFF Research Database (Denmark)

Jensen, Andreas Schmidt; Dignum, Virginia; Villadsen, Jørgen

2014-01-01

the expected behavior of the agents. Agents need to be able to reason about the regulations, so that they can act within the expected boundaries and work towards the objectives of the organization. In this paper, we describe the AORTA (Adding Organizational Reasoning to Agents) architecture for making agents...

Mathematical human phantoms and their application to radiation protection

International Nuclear Information System (INIS)

Yamaguchi, Yasuhiro

1998-01-01

This review described the characteristics of mathematical phantoms, their history over 30 years and their application. Mathematical phantoms are classified into two models of formula and voxel types. In the former, human body and organs are described by 2- and/or 3-D mathematical formula and can be seen as a combination of solid bodies like spheres, cubes and ovals. The phantom is composed from three tissue components (bone, lung and soft tissue) and made on data on Reference Man in ICRP Publ. 23. The latter voxel (volume pixel) phantom consists from a number of small cubes based on CT and MRI images of a certain man. For instance, the phantom CHILD, 1.54 x 1.54 x 8.00 mm 3 in size, is based on a 7-year old child, which consisting from about one million voxels. The mathematical phantom was first made in Oak Ridge National Laboratory in the middle of the nineteen-sixties, which have undergone various improvements to reach MIRD-5 phantom. Thereafter, many similitude phantoms have been made as a variation of MIRD-5, depending on age and sex (e.g., ADAM and EVA). Voxel phantom was made in the middle of nineteen-eighties and have undergone improvements which are continued even currently in Japan, U.S. etc. The mathematical phantoms are used for calculation of radiation transport program by Monte Carlo method in the field of radiation protection. Also in the field of medicine, the phantom is used for calculation of internal and external exposure doses, of correction constants of externally measuring instruments, of doses for neutron capture therapy and of A-bomb exposure doses in Hiroshima and Nagasaki for reevaluation. Recently, the development of phantom is in the current from formula phantom to voxel one due to the purpose of precision and standardization. (K.H.)

Recirculation zone length in renal artery is affected by flow spirality and renal-to-aorta flow ratio.

Science.gov (United States)

Javadzadegan, Ashkan; Fulker, David; Barber, Tracie

2017-07-01

Haemodynamic perturbations such as flow recirculation zones play a key role in progression and development of renal artery stenosis, which typically originate at the aorta-renal bifurcation. The spiral nature of aortic blood flow, division of aortic blood flow in renal artery as well as the exercise conditions have been shown to alter the haemodynamics in both positive and negative ways. This study focuses on the combinative effects of spiral component of blood flow, renal-to-aorta flow ratio and the exercise conditions on the size and distribution of recirculation zones in renal branches using computational fluid dynamics technique. Our findings show that the recirculation length was longest when the renal-to-aorta flow ratio was smallest. Spiral flow and exercise conditions were found to be effective in reducing the recirculation length in particular in small renal-to-aorta flow ratios. These results support the hypothesis that in renal arteries with small flow ratios where a stenosis is already developed an artificially induced spiral flow within the aorta may decelerate the progression of stenosis and thereby help preserve kidney function.

Hemodynamic Modeling of Surgically Repaired Coarctation of the Aorta.

Science.gov (United States)

Olivieri, Laura J; de Zélicourt, Diane A; Haggerty, Christopher M; Ratnayaka, Kanishka; Cross, Russell R; Yoganathan, Ajit P

2011-12-01

PURPOSE: Late morbidity of surgically repaired coarctation of the aorta includes early cardiovascular and cerebrovascular disease, shortened life expectancy, abnormal vasomodulator response, hypertension and exercise-induced hypertension in the absence of recurrent coarctation. Observational studies have linked patterns of arch remodeling (Gothic, Crenel, and Romanesque) to late morbidity, with Gothic arches having the highest incidence. We evaluated flow in native and surgically repaired aortic arches to correlate respective hemodynamic indices with incidence of late morbidity. METHODS: Three dimensional reconstructions of each remodeled arch were created from an anatomic stack of magnetic resonance (MR) images. A structured mesh core with a boundary layer was generated. Computational fluid dynamic (CFD) analysis was performed assuming peak flow conditions with a uniform velocity profile and unsteady turbulent flow. Wall shear stress (WSS), pressure and velocity data were extracted. RESULTS: The region of maximum WSS was located in the mid-transverse arch for the Crenel, Romanesque and Native arches. Peak WSS was located in the isthmus of the Gothic model. Variations in descending aorta flow patterns were also observed among the models. CONCLUSION: The location of peak WSS is a primary difference among the models tested, and may have clinical relevance. Specifically, the Gothic arch had a unique location of peak WSS with flow disorganization in the descending aorta. Our results suggest that varied patterns and locations of WSS resulting from abnormal arch remodeling may exhibit a primary effect on clinical vascular dysfunction.

A dynamic phantom for radionuclide renography

International Nuclear Information System (INIS)

Heikkinen, J.O.

1999-01-01

The aim of the study was to develop and test a dynamic phantom simulating radionuclide renography. The phantom consisted of five partly lead covered plastic containers simulating kidneys, heart, bladder and background (soft tissues, liver and spleen). Dynamics were performed with multiple movable steel plates between containers and a gamma camera. Control of the plates is performed manually with a stopwatch following exact time schedules. The containers were filled with activities ( 99m Tc) which produce count rates close to clinical situations. Count rates produced by the phantom were compared with ten clinical renography cases: five 99m Tc MAG3 and five 99m Tc DTPA examinations. Two phantom simulations were repeated three times with separate fillings, acquisitions and analyses. Precision errors as a coefficient of variation (CV) of repeated measurements were calculated and theoretical values were compared with the corresponding measured ones. A multicentre comparison was made between 19 nuclear medicine laboratories and three clinical cases were simulated with the phantom. Correlations between count rates produced by the phantom and clinical studies were r=0.964 for 99m Tc MAG3 (p 99m Tc DTPA (p max was 4.0±1.6%. Images and curves of the scanned phantom were close to a real patient in all 19 laboratories but calculated parameters varied: the difference between theoretical and measured values for T max was 6.8±6.2%. The difference between laboratories is most probably due to variations in acquisition protocols and analysis programs: 19 laboratories with 18 different protocols and 8 different programs. The dynamics were found to be repeatable and suitable for calibration purposes for radionuclide renography programs and protocols as well as for multicentre comparisons. (author)

Phantom inflation and the 'Big Trip'

International Nuclear Information System (INIS)

Gonzalez-Diaz, Pedro F.; Jimenez-Madrid, Jose A.

2004-01-01

Primordial inflation is regarded to be driven by a phantom field which is here implemented as a scalar field satisfying an equation of state p=ωρ, with ω-1. Being even aggravated by the weird properties of phantom energy, this will pose a serious problem with the exit from the inflationary phase. We argue, however, in favor of the speculation that a smooth exit from the phantom inflationary phase can still be tentatively recovered by considering a multiverse scenario where the primordial phantom universe would travel in time toward a future universe filled with usual radiation, before reaching the big rip. We call this transition the 'Big Trip' and assume it to take place with the help of some form of anthropic principle which chooses our current universe as being the final destination of the time transition

Charged black holes in phantom cosmology

Energy Technology Data Exchange (ETDEWEB)

Jamil, Mubasher; Qadir, Asghar; Rashid, Muneer Ahmad [National University of Sciences and Technology, Center for Advanced Mathematics and Physics, Rawalpindi (Pakistan)

2008-11-15

In the classical relativistic regime, the accretion of phantom-like dark energy onto a stationary black hole reduces the mass of the black hole. We have investigated the accretion of phantom energy onto a stationary charged black hole and have determined the condition under which this accretion is possible. This condition restricts the mass-to-charge ratio in a narrow range. This condition also challenges the validity of the cosmic-censorship conjecture since a naked singularity is eventually produced due to accretion of phantom energy onto black hole. (orig.)

Phantoms for IMRT dose distribution measurement and treatment verification

International Nuclear Information System (INIS)

Low, Daniel A.; Gerber, Russell L.; Mutic, Sasa; Purdy, James A.

1998-01-01

Background: The verification of intensity-modulated radiation therapy (IMRT) patient treatment dose distributions is currently based on custom-built or modified dose measurement phantoms. The only commercially available IMRT treatment planning and delivery system (Peacock, NOMOS Corp.) is supplied with a film phantom that allows accurate spatial localization of the dose distribution using radiographic film. However, measurements using other dosimeters are necessary for the thorough verification of IMRT. Methods: We have developed a phantom to enable dose measurements using a cylindrical ionization chamber and the localization of prescription isodose curves using a matrix of thermoluminescent dosimetry (TLD) chips. The external phantom cross-section is identical to that of the commercial phantom, to allow direct comparisons of measurements. A supplementary phantom has been fabricated to verify the IMRT dose distributions for pelvis treatments. Results: To date, this phantom has been used for the verification of IMRT dose distributions for head and neck and prostate cancer treatments. Designs are also presented for a phantom insert to be used with polymerizing gels (e.g., BANG-2) to obtain volumetric dose distribution measurements. Conclusion: The phantoms have proven useful in the quantitative evaluation of IMRT treatments

Methodologic aspects of acetylcholine-evoked relaxation of rabbit aorta

DEFF Research Database (Denmark)

Larsen, Kirsten Vendelbo; Nedergaard, Ove A.

1999-01-01

The acetylcholine-evoked relaxation of rabbit isolated thoracic aorta precontracted by phenylephrine was studied. Phenylephrine caused a steady contraction that was maintained for 6 h. In the presence of calcium disodium ethylenediaminetetraacetate (EDTA) and ascorbic acid the contraction decreased...

Reconstrução da aorta com conduto de pericárdio bovino corrugado

Directory of Open Access Journals (Sweden)

Claudio A. Salles

1998-04-01

Full Text Available No período de outubro de 1989 a maio de 1997, 40 pacientes portadores de dissecção aórtica, aneurisma da aorta, coarctação da aorta ou doença oclusiva aorto-ilíaca foram submetidos a reconstrução da aorta utilizando-se conduto de pericárdio bovino corrugado processado em glutaraldeído. A reconstrução total da aorta ascendente com substituição da valva aórtica e reimplante das artérias coronárias foi realizada em 9 pacientes, a simples substituição da aorta ascendente em 6, aorta torácica descendente em 2, arco aórtico em 1, aorta toracoabdominal em 1 e a aorta abdominal foi reconstruída em 21, incluindo pacientes submetidos a reconstrução aorto-ilíaca ou aorto-femoral. A mortalidade hospitalar foi de 8 (20% pacientes e as causas de óbito foram baixo débito cardíaco, recidiva da dissecção aórtica, falência de múltiplos órgãos e sangramento. O seguimento total foi de 128,4 pacientes-anos, com um seguimento médio de 4 anos por paciente. Complicações tardias relacionadas ao conduto vascular foram observadas em 4 pacientes, incluindo obstrução de um dos ramos do tubo bifurcado utilizado para reconstrução aorto-femoral e infecção em 3, resultando em degeneração secundária do conduto e formação de pseudo-aneurisma. Os 4 pacientes foram submetidos a reoperações, correspondendo a uma incidência de 3,1% ± 1,6% por paciente/ano. Ocorreram 5 óbitos tardios e as causas foram morte súbita, doença coronariana, pneumonia, septicemia e complicações metabólicas resultantes de diabetes e insuficiência renal crônica, correspondendo a uma incidência de 3,9% ± 1,7% por paciente/ano. A sobrevida atuarial em 9 anos foi 61,5% ± 9,2%, incluindo a mortalidade cirúrgica e a sobrevida atuarial livre de degeneração tissular estrutural primária do conduto biológico foi de 100%. O corrugamento do pericárdio, resultante da incorporação do princípio crimping utilizado nas próteses vasculares sint

Congenital diseases of the thoracic aorta. Role of MRI and MRA

International Nuclear Information System (INIS)

Russo, Vincenzo; Renzulli, Matteo; Palombara, Cesare la; Fattori, Rossella

2006-01-01

Aortic malformations may be associated with other congenital heart abnormalities or may present independently, as incidental findings in asymptomatic patients. For more than 30 years, conventional imaging techniques for detection and assessment of congenital anomalies of the aorta have been chest X-ray, echocardiography and angiography. In recent times, considerable interest in congenital aortic diseases has been shown, due to technical progresses of noninvasive imaging modalities. Among them, magnetic resonance imaging (MRI) almost certainly offers the greatest advantages, especially in young patients in which a radiation exposure must be avoided as much as possible. MRI provides an excellent visualization of vascular structures with a wide field of view, well suited for evaluation of the thoracic aorta malformations. With the implementation of magnetic resonance angiography (MRA) it is also possible to depict any relationship with supra-aortic or mediastinal vessels. Phase contrast technique allows identification of the hemodynamic significance of the aortic alteration. Some technical considerations, which include fast spin-echo, gradient-echo and, especially, MRA techniques with phase-contrast and contrast enhanced methods, are discussed and applied in the evaluation of congenital thoracic aorta diseases. (orig.)

Promotion of haematopoietic activity in embryonic stem cells by the aorta-gonad-mesonephros microenvironment

International Nuclear Information System (INIS)

Krassowska, Anna; Gordon-Keylock, Sabrina; Samuel, Kay; Gilchrist, Derek; Dzierzak, Elaine; Oostendorp, Robert; Forrester, Lesley M.; Ansell, John D.

2006-01-01

We investigated whether the in vitro differentiation of ES cells into haematopoietic progenitors could be enhanced by exposure to the aorta-gonadal-mesonephros (AGM) microenvironment that is involved in the generation of haematopoietic stem cells (HSC) during embryonic development. We established a co-culture system that combines the requirements for primary organ culture and differentiating ES cells and showed that exposure of differentiating ES cells to the primary AGM region results in a significant increase in the number of ES-derived haematopoietic progenitors. Co-culture of ES cells on the AM20-1B4 stromal cell line derived from the AGM region also increases haematopoietic activity. We conclude that factors promoting the haematopoietic activity of differentiating ES cells present in primary AGM explants are partially retained in the AM20.1B4 stromal cell line and that these factors are likely to be different to those required for adult HSC maintenance

Experimental phantom verification studies for simulations of light interactions with skin: liquid phantoms

CSIR Research Space (South Africa)

Karsten, A

2010-09-01

Full Text Available stream_source_info Karsten_2010_P.pdf.txt stream_content_type text/plain stream_size 5080 Content-Encoding UTF-8 stream_name Karsten_2010_P.pdf.txt Content-Type text/plain; charset=UTF-8 Experimental phantom verification... studies for simulations of light interactions with skin: Solid Phantoms Aletta E Karsten, A Singh Presented by: J E Smit National Laser Center CSIR South Africa akarsten@csir.co.za Slide 2 © CSIR 2009 www.csir.co.za Where...

DOMINANCE OF CORONARY ARTERY DISEASE AMONG PATIENTS WITH ANEURYSM OF ABDOMINAL AORTA

Directory of Open Access Journals (Sweden)

Maja Zdravkovic

2007-12-01

Full Text Available Persons with aneurysm of the abdominal aorta have high prevalence of risk factors of cardiovascular disease. It cannot be stated with certainty whether these persons die in a large number due to the existence of risk factors or the genesis and complications of aneurysm itself. In patients with aneurysm of the abdominal aorta, there is a high correlation with the coronary artery disease; therefore, the aim of the study was to prove whether or not this is the case. The patients in preparation for the resection of the abdominal aorta aneurysm at the Institute of Cardiovascular Disease underwent the examination. The study included 377 examinees, of whom 341 males and 36 females, aged 45 to 83 years, during the three-year interval (from 2004 to 2006. The aim of the study was to determine the dominance of the coronary artery disease among the patients with aneurysm of the abdominal aorta. In the process of analyzing the data obtained from patients and medical evidence, it was found out that a large number of the abdominal aortic aneurysm patients were at the same time the coronary artery disease patients (55,2%; Hi=15,04; p80 kg was larger, as well as the percentage of patients with hypertension (89% and increased levels of cholesterol and triglycerides (67%. There was a great number of those with the inherited factor (40%. It has been proven that the risk factors for the development of coronary artery disease are in direct association with the risk factors for the abdominal aortic aneurysm. Also, there is a great predominance of the coronary artery disease among the patients with aneurysm of the abdominal aorta. The coronary artery disease is one of the main risk factors. If we managed to prevent the appearance of this disease or achieve the timely diagnosing of it and eventual curing, we would be able to decrease the development of the abdominal aortic aneurysm well as the consequences and further complications.

Analysis of the thoracic aorta using a semi-automated post processing tool

International Nuclear Information System (INIS)

Entezari, Pegah; Kino, Aya; Honarmand, Amir R.; Galizia, Mauricio S.; Yang, Yan; Collins, Jeremy; Yaghmai, Vahid; Carr, James C.

2013-01-01

Objective: To evaluates a semi-automated method for Thoracic Aortic Aneurysm (TAA) measurement using ECG-gated Dual Source CT Angiogram (DSCTA). Methods: This retrospective HIPAA compliant study was approved by our IRB. Transaxial maximum diameters of outer wall to outer wall were studied in fifty patients at seven anatomic locations of the thoracic aorta: annulus, sinus, sinotubular junction (STJ), mid ascending aorta (MAA) at the level of right pulmonary artery, proximal aortic arch (PROX) immediately proximal to innominate artery, distal aortic arch (DIST) immediately distal to left subclavian artery, and descending aorta (DESC) at the level of diaphragm. Measurements were performed using a manual method and semi-automated software. All readers repeated their measurements. Inter-method, intra-observer and inter-observer agreements were evaluated according to intraclass correlation coefficient (ICC) and Bland–Altman plot. The number of cases with manual contouring or center line adjustment for the semi-automated method and also the post-processing time for each method were recorded. Results: The mean difference between semi-automated and manual methods was less than 1.3 mm at all seven points. Strong inter-method, inter-observer and intra-observer agreement was recorded at all levels (ICC ≥ 0.9). The maximum rate of manual adjustment of center line and contour was at the level of annulus. The average time for manual post-processing of the aorta was 19 ± 0.3 min, while it took 8.26 ± 2.1 min to do the measurements with the semi-automated tool (Vitrea version 6.0.0.1 software). The center line was edited manually at all levels, with most corrections at the level of annulus (60%), while the contour was adjusted at all levels with highest and lowest number of corrections at the levels of annulus and DESC (75% and 0.07% of the cases), respectively. Conclusion: Compared to the commonly used manual method, semi-automated measurement of vessel dimensions is

Simulation of a Quality Control Jaszczak Phantom with SIMIND Monte Carlo and Adding the Phantom as an Accessory to the Program

International Nuclear Information System (INIS)

Pirayesh Islamian, J.; Bahreyni Toosi, M. T.; Momennezhad, M.; Naseri, Sh.; Ljungberg, M.

2012-01-01

Quality control is an important phenomenon in nuclear medicine imaging. A Jaszczak SPECT Phantom provides consistent performance information for any SPECT or PET system. This article describes the simulation of a Jaszczak phantom and creating an executable phantom file for comparing assessment of SPECT cameras using SIMIND Monte Carlo simulation program which is well-established for SPECT. The simulation was based on a Deluxe model of Jaszczak Phantom with defined geometry. Quality control tests were provided together with initial imaging example and suggested use for the assessment of parameters such as spatial resolution, limits of lesion detection, and contrast comparing with a Siemens E.Cam SPECT system. The phantom simulation was verified by matching tomographic spatial resolution, image contrast, and also uniformity compared with the experiment SPECT of the phantom from filtered backprojection reconstructed images of the spheres and rods. The calculated contrasts of the rods were 0.774, 0.627, 0.575, 0.372, 0.191, and 0.132 for an experiment with the rods diameters of 31.8, 25.4, 19.1, 15.9, 12.7, and 9.5 mm, respectively. The calculated contrasts of simulated rods were 0.661, 0.527, 0.487, 0.400, 0.23, and 0.2 for cold rods and also 0.92, 0.91, 0.88, 0.81, 0.76, and 0.56 for hot rods. Reconstructed spatial tomographic resolution of both experiment and simulated SPECTs of the phantom obtained about 9.5 mm. An executable phantom file and an input phantom file were created for the SIMIND Monte Carlo program. This phantom may be used for simulated SPECT systems and would be ideal for verification of the simulated systems with real ones by comparing the results of quality control and image evaluation. It is also envisaged that this phantom could be used with a range of radionuclide doses in simulation situations such as cold, hot, and background uptakes for the assessment of detection characteristics when a new similar clinical SPECT procedure is being simulated.

Simulation of a Quality Control Jaszczak Phantom with SIMIND Monte Carlo and Adding the Phantom as an Accessory to the Program

Directory of Open Access Journals (Sweden)

Jalil Pirayesh Islamian

2012-03-01

Full Text Available Introduction Quality control is an important phenomenon in nuclear medicine imaging. A Jaszczak SPECT Phantom provides consistent performance information for any SPECT or PET system. This article describes the simulation of a Jaszczak phantom and creating an executable phantom file for comparing assessment of SPECT cameras using SIMIND Monte Carlo simulation program which is well-established for SPECT. Materials and Methods The simulation was based on a Deluxe model of Jaszczak Phantom with defined geometry. Quality control tests were provided together with initial imaging example and suggested use for the assessment of parameters such as spatial resolution, limits of lesion detection, and contrast comparing with a Siemens E.Cam SPECT system. Results The phantom simulation was verified by matching tomographic spatial resolution, image contrast, and also uniformity compared with the experiment SPECT of the phantom from filtered backprojection reconstructed images of the spheres and rods. The calculated contrasts of the rods were 0.774, 0.627, 0.575, 0.372, 0.191, and 0.132 for an experiment with the rods diameters of 31.8, 25.4, 19.1, 15.9, 12.7, and 9.5 mm, respectively. The calculated contrasts of simulated rods were 0.661, 0.527, 0.487, 0.400, 0.23, and 0.2 for cold rods and also 0.92, 0.91, 0.88, 0.81, 0.76, and 0.56 for hot rods. Reconstructed spatial tomographic resolution of both experiment and simulated SPECTs of the phantom obtained about 9.5 mm. An executable phantom file and an input phantom file were created for the SIMIND Monte Carlo program. Conclusion This phantom may be used for simulated SPECT systems and would be ideal for verification of the simulated systems with real ones by comparing the results of quality control and image evaluation. It is also envisaged that this phantom could be used with a range of radionuclide doses in simulation situations such as cold, hot, and background uptakes for the assessment of detection

Puzzles of dark energy in the Universe—phantom

International Nuclear Information System (INIS)

Dabrowski, Mariusz P

2015-01-01

This paper is devoted to some simple approach based on general physics tools to describe the physical properties of a hypothetical particle which can be the source of dark energy in the Universe known as phantom. Phantom is characterized by the fact that it possesses negative momentum and kinetic energy and that it gives dominant negative pressure which acts as antigravity. We consider a phantom harmonic oscillator in comparison to a standard harmonic oscillator. By using the first law of thermodynamics we explain why the energy density of the Universe grows when it is filled with phantom. We also show how the collision of phantom with a standard particle leads to extraction of energy from the former by the latter (i.e. from phantom to the standard) if their masses are different. The most striking of our conclusions is that the collision of phantom and standard particles of the same mass is impossible unless both of them are at rest and suddenly start moving with opposite velocities and kinetic energies. This effect is a classic analog of quantum mechanical particle pair creation in a strong electric field or physical vacuum. (paper)

Design and characterization of a device to quantify the magnetic drug targeting efficiency of magnetic nanoparticles in a tube flow phantom by magnetic particle spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Radon, Patricia, E-mail: patricia.radon@ptb.de; Löwa, Norbert; Gutkelch, Dirk; Wiekhorst, Frank

2017-04-01

The aim of magnetic drug targeting (MDT) is to transfer a therapeutic drug coupled to magnetic nanoparticles (MNP) to desired disease locations (e.g. tumor region) with the help of magnetic field gradients. To transfer the MDT approach into clinical practice a number of important issues remain to be solved. We developed and characterized an in-vitro flow phantom to provide a defined and reproducible MDT environment. The tube system of the flow phantom is directed through the detection coil of a magnetic particle spectroscopy (MPS) device to determine the targeting efficiency. MPS offers an excellent temporal resolution of seconds and an outstanding specific sensitivity of some nanograms of iron. In the flow phantom different MNP types, magnet geometries and tube materials can be employed to vary physical parameters like diameter, flow rate, magnetic targeting gradient, and MNP properties. - Highlights: • Flow phantom for magnetic targeting. • MPS for quantitative MNP detection. • ng detection limit for MNP.

Three-dimensional flow structures past a bio-prosthetic valve in an in-vitro model of the aortic root.

Science.gov (United States)

Hasler, David; Obrist, Dominik

2018-01-01

The flow field past a prosthetic aortic valve comprises many details that indicate whether the prosthesis is functioning well or not. It is, however, not yet fully understood how an optimal flow scenario would look, i.e. which subtleties of the fluid dynamics in place are essential regarding the durability and compatibility of a prosthetic valve. In this study, we measured and analyzed the 3D flow field in the vicinity of a bio-prosthetic heart valve in function of the aortic root size. The measurements were conducted within aortic root phantoms of different size, mounted in a custom-built hydraulic setup, which mimicked physiological flow conditions in the aorta. Tomographic particle image velocimetry was used to measure the 3D instantaneous velocity field at various instances. Several 3D fields (e.g. instantaneous and mean velocity, 3D shear rate) were analyzed and compared focusing on the impact of the aortic root size, but also in order to gain general insight in the 3D flow structure past the bio-prosthetic valve. We found that the diameter of the aortic jet relative to the diameter of the ascending aorta is the most important parameter in determining the characteristics of the flow. A large aortic cross-section, relative to the cross-section of the aortic jet, was associated with higher levels of turbulence intensity and higher retrograde flow in the ascending aorta.

ICRU activity in the field of phantoms in diagnostic radiology

International Nuclear Information System (INIS)

Wambersie, A.

1992-01-01

The ICRU Report on 'Phantoms and Computational Models in Radiation Therapy, Diagnosis and Protection' is presented. Different types of phantoms may be defined. They may be broadly categorized according to their primary function: dosimetry, calibration and imaging. Within each functional category, there are 3 types or designs of phantoms: body phantoms (anthropomorphic), standard phantoms and reference phantoms (used in the definition and specification of certain radiation quantities). In radiological imaging, anthropomorphic body phantoms are used for measuring the absorbed dose distribution resulting from imaging procedures. Standard phantoms have simple reproducible geometry and are used for comparing measurements under standard conditions of exposure. Imaging phantoms are useful for evaluating a given imaging system; they contain different types of test pieces. The report contains a major section on human anatomy, from fetus to adult with the variations due to ethnic origin. Tolerance levels for the phantoms (composition, dimensions) are proposed and quality assurance programs are outlined. The report contains extensive appendices; human anatomical data and full specification of over 80 phantoms and computational models. ICRU Report 46 on 'Photon, electron, proton and neutron interaction data for body tissues' is closely related to the field of phantoms. It is a logical continuation on ICRU Report 44 (1989) on 'Tissue substitutes in radiation dosimetry and measurements' and contains the interaction data for more than 100 tissues, from fetal to adult, including some diseased tissues

High prevalence of intracranial aneurysms in patients with aortic dissection or aneurysm: feasibility of extended aorta CT angiography with involvement of intracranial arteries.

Science.gov (United States)

Lee, Dahye; Ahn, Sung Jun; Cho, Eun-Suk; Kim, Yong Bae; Song, Suk-Won; Jung, Woo Sang; Suh, Sang Hyun

2017-10-01

Previous studies have suggested a higher prevalence of intracranial aneurysms (IAs) in patients with aortic aneurysms (AAs). To carry out a preliminary study to evaluate the prevalence of IAs in these patients and the diagnostic feasibility of extended aorta CT angiography (CTA), including intracranial arteries as well as the aorta. We retrospectively reviewed all patients with a clinical diagnosis of AA or aortic dissection (AD) who had undergone aorta CTA as well as MR angiography, CTA, and/or DSA of the brain between 2009 and 2014. Since 2012, the extended aorta CTA protocol has been applied in these patients. Characteristics of IAs were classified with baseline clinical data. For quantitative and qualitative assessment by two independent raters, brain images obtained by extended aorta CTA and brain CTA were compared. The radiation dose of the two aorta protocols was compared. The prevalence of IA was 22.2% (35/158). All IAs were detected by extended aorta CTA, except one small aneurysm (product of the extended aorta CTA increased with increment of the scan range (p=0.048). With a high prevalence of IAs in patients with ADs or AAs, extended aorta CTA could be used to evaluate aorta disease and IA in a single session. However, further prospective studies are needed to prove efficacy and safety of the extended aorta CTA protocol in patients with AAs or ADs. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Bolus timing in high-pitch CT angiography of the aorta

International Nuclear Information System (INIS)

Beeres, Martin; Loch, Matthias; Schulz, Boris; Kerl, Matthias; Al-Butmeh, Firas; Bodelle, Boris; Herrmann, Eva; Gruber-Rouh, Tatjana; Lee, Clara; Jacobi, Volkmar; Vogl, Thomas J.

2013-01-01

Objective: To investigate the bolus geometry in high-pitch CT angiography (CTA) of the aorta without ECG synchronisation in comparison to single-source CT. Methods: Overall 160 consecutive patients underwent CTA either in conventional single-source mode with a pitch of 1.2 (group 1), or in dual-source mode with a pitch of 3.0 (groups 2, 3 and 4) using different contrast media timings with bolus triggering at 140 HU (5 s, group 1; 10 s, group 2; 12 s, group 3; 14 s, group 4). Contrast material, saline flush, flow rate and kV/mAs settings were kept equal for optimum comparability. Aortic attenuation was measured along the z-axis of the patient at different anatomic landmarks and subjective image quality was compared. Results: The most homogeneous enhancement of the aorta was reached with a delay of 10 s after reaching the trigger threshold. The imaging length was not significantly different, but the examination time was significantly (p < 0.001) shorter in the high-pitch group (7.7 s vs. 1.7 s for group 1 vs. 2, 3 and 4). Conclusion: In high-pitch CT angiography using a start delay of 10 s after a trigger threshold of 140 HU in the descending aorta is reached, a homogenous contrast along the z-axis is accomplished

Patient specific 3D printed phantom for IMRT quality assurance

International Nuclear Information System (INIS)

Ehler, Eric D; Higgins, Patrick D; Dusenbery, Kathryn E; Barney, Brett M

2014-01-01

The purpose of this study was to test the feasibility of a patient specific phantom for patient specific dosimetric verification. Using the head and neck region of an anthropomorphic phantom as a substitute for an actual patient, a soft-tissue equivalent model was constructed with the use of a 3D printer. Calculated and measured dose in the anthropomorphic phantom and the 3D printed phantom was compared for a parallel-opposed head and neck field geometry to establish tissue equivalence. A nine-field IMRT plan was constructed and dose verification measurements were performed for the 3D printed phantom as well as traditional standard phantoms. The maximum difference in calculated dose was 1.8% for the parallel-opposed configuration. Passing rates of various dosimetric parameters were compared for the IMRT plan measurements; the 3D printed phantom results showed greater disagreement at superficial depths than other methods. A custom phantom was created using a 3D printer. It was determined that the use of patient specific phantoms to perform dosimetric verification and estimate the dose in the patient is feasible. In addition, end-to-end testing on a per-patient basis was possible with the 3D printed phantom. Further refinement of the phantom construction process is needed for routine use. (paper)

Influence of Manufacturing Processes on the Performance of Phantom Lungs

International Nuclear Information System (INIS)

Traub, Richard J.

2008-01-01

Chest counting is an important tool for estimating the radiation dose to individuals who have inhaled radioactive materials. Chest counting systems are calibrated by counting the activity in the lungs of phantoms where the activity in the phantom lungs is known. In the United States a commonly used calibration phantom was developed at the Lawrence Livermore National Laboratory and is referred to as the Livermore Torso Phantom. An important feature of this phantom is that the phantom lungs can be interchanged so that the counting system can be challenged by different combinations of radionuclides and activity. Phantom lungs are made from lung tissue substitutes whose constituents are foaming plastics and various adjuvants selected to make the lung tissue substitute similar to normal healthy lung tissue. Some of the properties of phantom lungs cannot be readily controlled by phantom lung manufacturers. Some, such as density, are a complex function of the manufacturing process, while others, such as elemental composition of the bulk plastic are controlled by the plastics manufacturer without input, or knowledge of the phantom manufacturer. Despite the fact that some of these items cannot be controlled, they can be measured and accounted for. This report describes how manufacturing processes can influence the performance of phantom lungs. It is proposed that a metric that describes the brightness of the lung be employed by the phantom lung manufacturer to determine how well the phantom lung approximates the characteristics of a human lung. For many purposes, the linear attenuation of the lung tissue substitute is an appropriate surrogate for the brightness

Phantom and animal studies of a new hepatobiliary agent for MR imaging: comparison of Gd-DTPA-DeA with Gd-EOB-DTPA.

Science.gov (United States)

Yoshikawa, Kohki; Inoue, Yusuke; Akahane, Masaaki; Shimada, Morio; Itoh, Sayaka; Seno, Atsushi; Hayashi, Sanshin

2003-08-01

To investigate the characteristics of Gd-DTPA-DeA as a hepatobiliary contrast agent for MR imaging in comparison with those of Gd-EOB-DTPA. We undertook phantom experiments to assess T1 relaxivity for Gd-DTPA-DeA, Gd-EOB-DTPA, and Gd-DTPA in human plasma. For Gd-DTPA-DeA and Gd-EOB-DTPA, we evaluated the contrast effect in rats using an SPGR sequence. The contrast ratios of liver and abdominal aorta were measured up to 21 minutes after intravenous administration of the agents. Visualization of the bile duct and renal pelvis was also assessed. In human plasma, T1 relaxivity was similar for Gd-DTPA-DeA and Gd-EOB-DTPA, and higher than those for Gd-DTPA. Whereas the contrast ratio of liver peaked about five minutes after the injection of Gd-EOB-DTPA and was followed by a subsequent decline, a continuous rise was shown for Gd-DTPA-DeA, resulting in a larger maximal contrast effect. Contrast ratios of the abdominal aorta were larger for Gd-DTPA-DeA. Biliary excretion was observed for both agents but occurred earlier with Gd-EOB-DTPA. While renal excretion was shown for all rats three minutes after the injection of Gd-EOB-DTPA, it was not observed for Gd-DTPA-DeA. Gd-DTPA-DeA may be used as a hepatobiliary contrast agent and shows different pharmacokinetics from Gd-EOB-DTPA. Copyright 2003 Wiley-Liss, Inc.

Treatment of traumatic rupture of the thoracic aorta

Directory of Open Access Journals (Sweden)

Davidović Lazar

2008-01-01

Full Text Available INTRODUCTION Interest for traumatic thoracic aorta rupture stems from the fact that its number continually increases, and it can be rapidly lethal. OBJECTIVE The aim of this study is to present early and long term results as well as experiences of our team in surgical treatment of traumatic thoracic aorta rupture. METHOD Our retrospective study includes 12 patients with traumatic thoracic aorta rupture treated between 1985 and 2007. There were 10 male and two female patients of average age 30.75 years (18-74. RESULTS In six cases, primary diagnosis was established during the first seven days days after trauma, while in 6 more than one month later. In 11 cases, classical open surgical procedure was performed, while endovascular treatment was used in one patient. Three (25% patients died, while two (16.6% had paraplegia. Nine patients (75% were treated without complications, and are in good condition after a mean follow-up period of 9.7 years (from one month to 22 years. CONCLUSION Surgical treatment requires spinal cord protection to prevent paraplegia, using cardiopulmonary by-pass (three of our cases or external heparin-bonded shunts (five of our cases. Cardiopulmonary by-pass is followed with lower incidence of paraplegia, however it is not such a good solution for patients with polytrauma because of hemorrhage. The endovascular repair is a safe and feasible procedure in the acute phase, especially because of traumatic shock and polytrauma which contributes to higher mortality rate after open surgery. On the other hand, in chronic postrauamatic aortic rupture, open surgical treatment is connected with a lower mortality rate and good long-term results. There have been no published data about long-term results of endovascular treatment in the chronic phase.

Análisis del comportamiento mecánico en una sección de la aorta // Mechanical behavior analysis in an aorta section

Directory of Open Access Journals (Sweden)

A. González-Martin

2009-05-01

Full Text Available La importancia social de las enfermedades arteriales motiva el interés en desarrollar estudios sobreel comportamiento mecánico de las paredes arteriales que aporten información para la prácticamédica, ya que estas enfermedades están fuertemente relacionadas con factores mecánicos comoson los estados de deformación y tensión. El presente trabajo ofrece una metodología para analizarel comportamiento mecánico de una arteria (la aorta. Dicho análisis parte de una geometría realconstruida a partir de imágenes médicas. En la formulación del modelo de elementos finitos seescogió un material con comportamiento no-lineal, con grandes deformaciones, hiperelástico, nohomogéneoy ortótropico. A la hora de analizar los resultados logrados y compararlos con losresultados obtenidos por otros autores no es posible establecer una comparación debido a losdiferentes métodos de ensayo empleados por distintos autores y la dificultad en laexperimentación en arterias humanas, solo es posible establecer zonas criticas en las cuales sepresente algún tipo de enfermedad arterial.Palabras claves: aorta, modelación, elementos finitos (EF, hiperelásticidad.______________________________________________________________________________AbstractThe social importance of the arterial illnesses motivates the interest in developing studies on themechanical behavior of the arterial walls. The medical practice has pointed that these illnesses arestrongly related with mechanical factors, such as states of deformation and tension as other relatedparameters. The present work offers a methodology to analyze the mechanical behavior of anartery (the aorta. This analysis uses a real geometry model that has been built based on medicalimages. In the formulation of the finite elements model the material has been considered with ano-linear behavior, with big deformations, hyperplasic, no-homogeneous and orthotropic. It is notpossible to establish comparisons between the

Mathematical phantoms for evaluation of age-specific internal dose

International Nuclear Information System (INIS)

Cristy, M.

1980-01-01

A series of mathematical phantoms representing children has been developed for use with photon transport codes. These phantoms, patterned after the Fisher-Snyder adult phantom, consist of simple mathematical expressions for the boundaries of the major organs and body sections. The location and shape of the organs are consistent with drawings depicting developmental anatomy, with the organ volumes assigned such that the masses at the various ages conform closely with the data presented in Reference Man. The explicit mathematical expressions for the various ages overcome the potential misrepresentation of organ sizes that occurred in phantoms derived from simple mathematical transformations of the adult phantom. Female breast tissue has been added to the phantoms, including the adult, now allowing assessment of doses to this organ

Surgical exclusion of postsurgical pseudoaneurysm of the ascending aorta

Energy Technology Data Exchange (ETDEWEB)

Barik, Ramachandra; Patnaik, Amar Narayana [Department of Cardiology, Nizam' s Institute of Medical Sciences, Hyderabad, Andhra Pradesh (India); Kumar, Ravintula Venkata; Mohapatra, Rudra Prasad [Department of Cardiothoracic Surgery, Nizam' s Institute of Medical Sciences, Hyderabad, Andhra Pradesh (India); Medep, Vikas; Nemani, Lalita [Department of Cardiology, Nizam' s Institute of Medical Sciences, Hyderabad, Andhra Pradesh (India)

2014-01-01

Pseudoaneurysm of ascending aorta after cardiac surgery is rare in children. We report a case of successful surgical exclusion of ascending aortic pseudoaneurysm in a 15-year-old boy. The neck of the aneurysm was in close proximity to the right coronary artery (RCA)

Aorta Fluorescence Imaging by Using Confocal Microscopy

OpenAIRE

Wang, Chun-Yang; Tsai, Jui-che; Chuang, Ching-Cheng; Hsieh, Yao-Sheng; Sun, Chia-Wei

2011-01-01

The activated leukocyte attacked the vascular endothelium and the associated increase in VEcadherin number was observed in experiments. The confocal microscopic system with a prism-based wavelength filter was used for multiwavelength fluorescence measurement. Multiwavelength fluorescence imaging based on the VEcadherin within the aorta segment of a rat was achieved. The confocal microscopic system capable of fluorescence detection of cardiovascular tissue is a useful tool for measuring the bi...

Relationship between aneurism of ascending part of aorta and syndrome of connective tissue dysplasia

Directory of Open Access Journals (Sweden)

Osovska N.Yu.

2014-11-01

Full Text Available The paper identifies the main reasons for the development of an aneurysm of the ascending aorta and predictors of its complications in patients of all ages. To determine the cause and age-associated risk factors for aneurysms there were examined 154 patients with the presence of the expansion of the root and / or ascending aorta of more than 40 mm, according to echocardiographic examination. Patients were divided into 4 categories by age: 18-29 years, 30-44 years 45-59 years 60-74 years. Instrumental methods of examination: echocardiography, ECG, ECG monitoring and blood pressure, heart rate variability, ultrasound of internal organs were used. Syndrome of connective tissue dysplasia was established according to the criteria of the working group of the British Society of Rheumatology. Joint hypermobility syndrome was determined according to the Brayton criteria. Statistical processing was carried out by methods of variation statistic program StatSoft "Statistica" v.10.0. It was established that in young and middle aged patients the cause of aneurysm of ascending aorta more often is connective tissue dysplasia syndrome. In older patients the main cause of aneurysm of ascending aorta is associated with left ventricular hypertrophy and decreased contractile function of the heart.

Ruptured tuberculous false aneurysm of the abdominal aorta: a case report.

Science.gov (United States)

Mechchat, Alae; Lekehal, Brahim; Mesnaoui, Abbes; Ammar, Fannid; Bensaid, Younes

2011-01-01

Tuberculous false aneurysm of the aorta is rare and has an unpredictable complication of aneurysm rupture. We report a case of a 32-year old woman who was referred to the Department of Vascular Surgery, Avicenne Hospital for severe abdominal pain. Chest x-ray revealed miliary tuberculosis. Contrast enhanced computed tomography (CT) scan showed a false aortic aneurysm involving the juxtarenal aorta. Antituberculous treatment was started because of high presumption of tuberculosis. Five days later, the patient presented with symptoms of aneurysm rupture. She underwent an emergency a surgical resection of the aneurysm with repair of the aortic wall defect by a Dacron Silver patch. The histopathologic examination of the aortic wall showed features of tuberculosis.

Elastin and collagen fibre microstructure of the human aorta in ageing and disease: a review

Science.gov (United States)

Tsamis, Alkiviadis; Krawiec, Jeffrey T.; Vorp, David A.

2013-01-01

Aortic disease is a significant cause of death in developed countries. The most common forms of aortic disease are aneurysm, dissection, atherosclerotic occlusion and ageing-induced stiffening. The microstructure of the aortic tissue has been studied with great interest, because alteration of the quantity and/or architecture of the connective fibres (elastin and collagen) within the aortic wall, which directly imparts elasticity and strength, can lead to the mechanical and functional changes associated with these conditions. This review article summarizes the state of the art with respect to characterization of connective fibre microstructure in the wall of the human aorta in ageing and disease, with emphasis on the ascending thoracic aorta and abdominal aorta where the most common forms of aortic disease tend to occur. PMID:23536538

Surgical exclusion of postsurgical pseudoaneurysm of the ascending aorta

Science.gov (United States)

Barik, Ramachandra; Patnaik, Amar Narayana; Kumar, Ravintula Venkata; Mohapatra, Rudra Prasad; Medep, Vikas; Nemani, Lalita

2014-01-01

Pseudoaneurysm of ascending aorta after cardiac surgery is rare in children. We report a case of successful surgical exclusion of ascending aortic pseudoaneurysm in a 15-year-old boy. The neck of the aneurysm was in close proximity to the right coronary artery (RCA). PMID:24987261

Surgical exclusion of postsurgical pseudoaneurysm of the ascending aorta

Directory of Open Access Journals (Sweden)

Ramachandra Barik

2014-01-01

Full Text Available Pseudoaneurysm of ascending aorta after cardiac surgery is rare in children. We report a case of successful surgical exclusion of ascending aortic pseudoaneurysm in a 15-year-old boy. The neck of the aneurysm was in close proximity to the right coronary artery (RCA.

Large mobile thrombus in non-atherosclerotic thoracic aorta as the source of peripheral arterial embolism

Directory of Open Access Journals (Sweden)

Brkovic Zoran

2005-11-01

Full Text Available Abstract The presence of thrombi in the atherosclerotic and/or aneurysmatic aorta with peripheral arterial embolism is a common scenario. Thrombus formation in a morphologically normal aorta, however, is a rare event. A 50 years old woman was admitted to the mergency department for pain, coldness, and anesthesia in the the left foot. She had a 25 years history of cigarette smoking, a history of postmenopausal hormone replacement therapy (HRT, hypercholesterolemia and hyperfibrinogenemia. An extensive serologic survey for hypercoagulability, including antiphospholipid antibodies, and vasculitis disorders was negative. Transesophageal echocardiography revealed a large, pedunculated and hypermobile thrombus attached to the aortic wall 5 cm distal of the left subclavian artery. The patient was admitted to the surgery department, where a 15 cm long fresh, parietal thrombus could be removed from the aorta showing no macroscopic wall lesions or any other morphologic abnormalities. This case report demonstrates the possibility of evolving a large, pedunculated thrombus in a morphologically intact aorta in a postmenopausal woman with thrombogenic conditions such as hyperfibrinogenemia, hypercholesterolemia, smoking and HRT. For these patients, profiling the individual risk and weighing the benefits against the potential risks is warranted before prescribing HRT.

Aorta cross-section calculation and 3D visualization from CT or MRT data using VRML

Science.gov (United States)

Grabner, Guenther; Modritsch, Robert; Stiegmaier, Wolfgang; Grasser, Simon; Klinger, Thomas

2005-04-01

Quantification of vessel diameters of artherosclerotic or congenital stenosis is very important for the diagnosis of vascular diseases. The aorta extraction and cross-section calculation is a software-based application that offers a three-dimensional, platform-independent, colorized visualization of the extracted aorta with augmented reality information of MRT or CT datasets. This project is based on different types of specialized image processing algorithms, dynamical particle filtering and complex mathematical equations. From this three-dimensional model a calculation of minimal cross sections is performed. In user specified distances, the aorta is cut in differently defined directions which are created through vectors with varying length. The extracted aorta and the derived minimal cross-sections are then rendered with the marching cube algorithm and represented together in a three-dimensional virtual reality with a very high degree of immersion. The aim of this study was to develop an imaging software that delivers cardiologists the possibility of (i) furnishing fast vascular diagnosis, (ii) getting precise diameter information, (iii) being able to process exact, local stenosis detection (iv) having permanent data storing and easy access to former datasets, and (v) reliable documentation of results in form of tables and graphical printouts.

In vivo and in vitro hypotensive effect of aqueous extract of Moringa stenopetala.

Science.gov (United States)

Mengistu, M; Abebe, Y; Mekonnen, Y; Tolessa, T

2012-12-01

Moringa stenopetala, Baker f. (Moringaceae) is used for food and medicine in Southern Ethiopia. To substantiate the hypotensive effect of M. stenopetala in vivo and in vitro. An in vivo experiment was carried out on male guinea pigs anaesthetized with pentobarbital. The arterial blood pressure was recorded from a carotid artery filled with heparinized saline via an arterial cannula connected to a pressure transducer. For the in vitro experiment the descending thoracic aorta was removed and kept moistened in Krebs-Henseleit solution and then mounted in a 20ml tissue bath maintained at 37°C and bubbled with a mixture of 95% oxygen and 5% carbon dioxide. Crude aqueous leaf extract of M. stenopetala caused significant fall in systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial blood pressure (MABP) at doses of 10, 20, 30 and 40 mg/kg in normotensive anaesthetized guinea pigs (n = 12). The effect might have been mediated by non-autonomic nervous system as the effect is not altered by atropine and propranolol. The extract also caused significant dose and time dependent inhibition of K(+) induced contraction on guinea pig aorta. M.stenopetala has blood pressure lowering effect substantiating the use of the plant in traditional medicine.

Phantom Pain

Science.gov (United States)

... Because this is yet another version of tangled sensory wires, the result can be pain. A number of other factors are believed to contribute to phantom pain, including damaged nerve endings, scar tissue at the site of the amputation and the physical memory of pre-amputation pain in the affected area. ...

Comparison of different phantoms used in digital diagnostic imaging

Energy Technology Data Exchange (ETDEWEB)

Bor, Dogan, E-mail: bor@eng.ankara.edu.tr [Ankara University, Faculty of Engineering, Department of Engineering Physics. Tandogan, 06100 Ankara (Turkey); Unal, Elif, E-mail: elf.unall@gmail.com [Radat Dosimetry Laboratory Services, 06830, Golbasi, Ankara (Turkey); Uslu, Anil, E-mail: m.aniluslu@gmail.com [Radat Dosimetry Laboratory Services, 06830, Golbasi, Ankara (Turkey)

2015-09-21

The organs of extremity, chest, skull and lumbar were physically simulated using uniform PMMA slabs with different thicknesses alone and using these slabs together with aluminum plates and air gaps (ANSI Phantoms). The variation of entrance surface air kerma and scatter fraction with X-ray beam qualities was investigated for these phantoms and the results were compared with those measured from anthropomorphic phantoms. A flat panel digital radiographic system was used for all the experiments. Considerable variations of entrance surface air kermas were found for the same organs of different designs, and highest doses were measured for the PMMA slabs. A low contrast test tool and a contrast detail test object (CDRAD) were used together with each organ simulation of PMMA slabs and ANSI phantoms in order to test the clinical image qualities. Digital images of these phantom combinations and anthropomorphic phantoms were acquired in raw and clinically processed formats. Variation of image quality with kVp and post processing was evaluated using the numerical metrics of these test tools and measured contrast values from the anthropomorphic phantoms. Our results indicated that design of some phantoms may not be efficient enough to reveal the expected performance of the post processing algorithms.

45Ca2+movements induced by Ca2+chloride in isolated rat aorta under K+-free conditions

NARCIS (Netherlands)

Wermelskirchen, D.; Nebel, U.; Wirth, A.; Wilffert, B.

1991-01-01

Increasing the extracellular Ca2+concentration induced a dihydropyridine-insensitive contraction in the isolated rat aorta bathed in K+-free solution. To obtained further insight into the mechanisms of this contraction45Ca2+uptake measurements were carried out with isolated rat aorta. Increasing the

CA-45(2+) MOVEMENTS INDUCED BY CA2+ CHLORIDE IN ISOLATED RAT AORTA UNDER K+-FREE CONDITIONS

NARCIS (Netherlands)

WERMELSKIRCHEN, D; NEBEL, U; WIRTH, A; WILFFERT, B

1991-01-01

Increasing the extracellular Ca2+ concentration induced a dihydropyridine-insensitive contraction in the isolated rat aorta bathed in K+-free solution. To obtain further insight into the mechanism of this contraction Ca-45(2+) uptake measurements were carried out with isolated rat aorta. Increasing

AORTA: Adding Organizational Reasoning to Agents

DEFF Research Database (Denmark)

Jensen, Andreas Schmidt; Dignum, Virginia

2014-01-01

the expected behavior of the agents. Agents need to be able to reason about the regulations, so that they can act within the expected boundaries and work towards the objectives of the organization. This extended abstract introduces AORTA, a component that can be integrated into agents’ reasoning mechanism......, allowing them to reason about (and act upon) regulations specified by an organizational model using simple reasoning rules. The added value is that the organizational model is independent of that of the agents, and that the approach is not tied to a specific organizational model....

Valva aórtica bicúspide: fundamentos teóricos e clínicos para substituição simultânea da aorta ascendente Bicuspid aortic valve: theoretical and clinical aspects of concomitant ascending aorta replacement

Directory of Open Access Journals (Sweden)

Mauro Paes Leme De Sá

2009-06-01

Full Text Available A valva aórtica bicúspide (VAB está associada à ectasia ânulo-aórtica, aneurisma e dissecção da aorta ascendente. A alta incidência desta malformação congênita e doença da aorta sugere íntima relação entre os fenômenos. Anormalidades ocorrendo em diferentes fases da migração das células da crista neural podem ser responsáveis pela ocorrência em anormalidades na valva aórtica, na camada média da aorta ascendente e nos vasos do arco aórtico. Estudos prévios revelam que mesmo indivíduos com VAB normal ou com disfunção leve podem apresentar dilatação da raiz aórtica. Os autores acreditam que somente as alterações hemodinâmicas produzidas por uma VAB sem estenose ou insuficiência parecem ser insuficientes para as graves complicações vasculares observadas nos portadores de VAB. Vários mecanismos têm sido propostos para explicar os achados moleculares e histológicos desta doença. Encontramos a redução da fibrilina-1 na aorta ascendente e artéria pulmonar como possível causa. Histologicamente, a aorta ascendente pode apresentar necrose cística da média e fragmentação elástica, semelhante àquela encontrada em portadores de síndrome de Marfan. Vários autores atualmente recomendam que em se operando um paciente com VAB, especialmente aqueles com insuficiência aórtica, mesmo na presença de uma discreta dilatação (45 mm deve-se substituir a valva aórtica e a aorta ascendente concomitantemente quando a expectativa de vida exceder 10 anos, para se prevenir futuros aneurismas ou rupturas.Bicuspid aortic valve (BAV is associated with annuloaortic ectasia, dissection and ascending aortic aneurysm. The high incidence of this congenital malformation and aortic disease suggests a close correlation between the two phenomena. Abnormalities in different phases of cell migration of the neural crest might be responsible for the occurrence of abnormalities in the aortic valve, media layer of the ascending aorta

Matrix metalloproteinases. Their role in degenerative chronic diseases of abdominal aorta.

Science.gov (United States)

Palombo, D; Maione, M; Cifiello, B I; Udini, M; Maggio, D; Lupo, M

1999-04-01

The main chronic degenerative diseases of the abdominal aorta, namely aneurysmatic and steno-obstructive pathologies, have a common denominator: atherosclerosis. Both pathologies are characterised by the destruction of the structural integrity of the extracellular protein matrix (ME). A number of studies have shown the presence and involvement of a group of enzymes with proteolytic activity towards one or more ME components, the matrix metalloproteinases (MMPs), in the pathogenesis of aneurysms of the abdominal aorta. Other authors have underlined the role of MMPs in the proliferation and migration process of smooth muscle cells into the intima in the pathogenesis of atheromasic plaque. The aim of this study was to evaluate the possible role of these enzymes in the pathogenesis of chronic degenerative diseases of the aorta. Fragments of aortic wall were removed from patients undergoing elective aortic surgery for aneurysms (14 patients) or aortic steno-obstruction (4 patients). The samples obtained were treated appropriately and then subject to immunohistochemical analysis. The preparations were incubated with specific anti-MMP antibodies and were also incubated with substrate and chromogen, forming a pigmented precipitate on the site of the antigen, before being observed using an optic microscopic at an enlargement of 250x. Nuclear positivity linked to the presence of the antigen testified the validity of staining. Lastly, the MMP INDEX, or in other words the number of positive cells out of 100, was stained in the adventitia and in the tunica media in each preparation. MMPs were divided into three main groups: interstitial collagenase (MMP1) which degrade type I and III native collagen; gelatinases (MMP9, MMP2) which act on elastin and type IV collagen; stromelysins (MMP3) with specific proteolytic action towards proteoglycans, fibronectin and laminine. In our experience, those preparations obtained from aorta affected by steno-obstructive pathologies (4 patients

Effect of high density lipoproteins on permeability of rabbit aorta to low density lipoproteins

International Nuclear Information System (INIS)

Klimov, A.N.; Popov, V.A.; Nagornev, V.A.; Pleskov, V.M.

1985-01-01

A study was made on the effect of high density lipoproteins (HDL) on the permeability of rabbit aorta to low density lipoproteins (LDL) after intravenous administration of human HDL and human ( 125 I)LDL to normal and hypercholesterolemic rabbits. Evaluation of radioactivity in plasma and aorta has shown that the administration of a large dose of HDL decreased the aorta permeability rate for ( 125 I)LDL on an average by 19% in normal rabbits, and by 45% in rabbits with moderate hypercholesterolemia. A historadiographic study showed that HDL also decreased the vessel wall permeability to ( 125 I)LDL in normal and particularly in hypercholesterolemic animals. The suggestion was made that HDL at very high molar concentration can hamper LDL transportation through the intact endothelial layer into the intima due to the ability of HDL to compete with LDL in sites of low affinity on the surface of endothelial cells. (author)

Mechanics, Mechanobiology, and Modeling of Human Abdominal Aorta and Aneurysms

Science.gov (United States)

Humphrey, J.D.; Holzapfel, G.A.

2011-01-01

Biomechanical factors play fundamental roles in the natural history of abdominal aortic aneurysms (AAAs) and their responses to treatment. Advances during the past two decades have increased our understanding of the mechanics and biology of the human abdominal aorta and AAAs, yet there remains a pressing need for considerable new data and resulting patient-specific computational models that can better describe the current status of a lesion and better predict the evolution of lesion geometry, composition, and material properties and thereby improve interventional planning. In this paper, we briefly review data on the structure and function of the human abdominal aorta and aneurysmal wall, past models of the mechanics, and recent growth and remodeling models. We conclude by identifying open problems that we hope will motivate studies to improve our computational modeling and thus general understanding of AAAs. PMID:22189249

Computed Tomography of the complications of prosthetic surgery of the abdominal aorta

International Nuclear Information System (INIS)

Giovagnorio, Francesco; Andreoli, Chiara; De Cicco, Maria Luisa

1997-01-01

Computerized Tomography has gained an important role in the diagnosis of the complications of prosthetic surgery of the abdominal aorta: the importance of such complications come from their frequency, which is proportional to the increasing number of interventions, and their severity. The authors investigated the CT patterns of the most frequent complications. 24 patients referred for strongly suspected postoperative complications were examined in 2 years: fever and leukocytosis (20 cases) and progressive anemia (4 cases) were the most frequent findings. The operation had been performed 7± 12 weeks before (2 patients were excluded because surgery dated less than 3 weeks. 14 patients had infective complications: thickening (57%) and inhomogeneity (43%) of the periprosthetic wrap and ectopic gas bubble (78%) were the most frequent Computerized Tomography findings. The authors also observed 2 periprosthetic hematomas, 1 aneurysm relapse and 1 prosthetic graft rupture. In conclusion, CT confirmed its important role in the study of the complications of prosthetic aortic surgery, despite its know poor specificity in the demonstration of the aorta in the first 2-3 months postoperatively, in the initial stages of infection and in the diagnosis of aorta-enteric fistulas

Energy Efficient Resource Allocation for Phantom Cellular Networks

KAUST Repository

Abdelhady, Amr

2016-04-01

Multi-tier heterogeneous networks have become an essential constituent for next generation cellular networks. Meanwhile, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for the recently proposed two-tier network architecture known as phantom cellular networks. The optimization framework includes both EE and SE. First, we consider sparsely deployed cells experiencing negligible interference and assume perfect channel state information (CSI). For this setting, we propose an algorithm that finds the SE and EE resource allocation strategies. Then, we compare the performance of both design strategies versus number of users, and phantom cells share of the total available resource units (RUs). We aim to investigate the effect of some system parameters to achieve improved SE performance at a non-significant loss in EE performance, or vice versa. It is found that increasing phantom cells share of RUs decreases the SE performance loss due to EE optimization when compared with the optimized SE performance. Second, we consider the densely deployed phantom cellular networks and model the EE optimization problem having into consideration the inevitable interference and imperfect channel estimation. To this end, we propose three resource allocation strategies aiming at optimizing the EE performance metric of this network. Furthermore, we investigate the effect of changing some of the system parameters on the performance of the proposed strategies, such as phantom cells share of RUs, number of deployed phantom cells within a macro cell coverage, number of pilots and the maximum power available for transmission by the phantom cells BSs. It is found that increasing the number of pilots deteriorates the EE performance of the whole setup, while increasing maximum power available for phantom cells transmissions reduces the EE of the whole setup in a

Chronic Treatment with Minoxidil Induces Elastic Fiber Neosynthesis and Functional Improvement in the Aorta of Aged Mice.

Science.gov (United States)

Coquand-Gandit, Marion; Jacob, Marie-Paule; Fhayli, Wassim; Romero, Beatriz; Georgieva, Miglena; Bouillot, Stéphanie; Estève, Eric; Andrieu, Jean-Pierre; Brasseur, Sandrine; Bouyon, Sophie; Garcia-Honduvilla, Natalio; Huber, Philippe; Buján, Julia; Atanasova, Milena; Faury, Gilles

2017-06-01

Normal arterial aging processes involve vascular cell dysfunction associated with wall stiffening, the latter being due to progressive elastin and elastic fiber degradation, and elastin and collagen cross-linking by advanced glycation end products (AGEs). These processes progressively lead to cardiovascular dysfunction during aging. Elastin is only synthesized during late gestation and childhood, and further degradation occurring throughout adulthood cannot be physiologically compensated by replacement of altered material. However, the ATP-dependent K + channel opener minoxidil has been shown to stimulate elastin expression in vitro and in vivo in the aorta of young adult rats. Therefore, we have studied the effect of a 10-week chronic oral treatment with minoxidil (120 mg/L in drinking water) on the aortic structure and function in aged 24-month-old mice. Minoxidil treatment increased tropoelastin, fibulin-5, and lysyl-oxidase messenger RNA levels, reinduced a moderate expression of elastin, and lowered the levels of AGE-related molecules. This was accompanied by the formation of newly synthesized elastic fibers, which had diverse orientations in the wall. A decrease in the glycation capacity of aortic elastin was also produced by minoxidil treatment. The ascending aorta also underwent a minoxidil-induced increase in diameter and decrease in wall thickness, which partly reversed the age-associated thickening and returned the wall thickness value and strain-stress relation closer to those of younger adult animals. In conclusion, our results suggest that minoxidil presents an interesting potential for arterial remodeling in an antiaging perspective, even when treating already aged animals.

[Psychotherapies for the Treatment of Phantom Limb Pain].

Science.gov (United States)

Cárdenas, Katherine; Aranda, Mariana

The phantom limb pain has been described as a condition in which patients experience a feeling of itching, spasm or pain in a limb or body part that has been previously amputated. Such pain can be induced by a conflict between the representation of the visual and proprioceptive feedback of the previously healthy limb. The phantom limb pain occurs in at least 42 to 90% of amputees. Regular drug treatment of phantom limb pain is almost never effective. A systematic review of the literature was conducted in Medline and Cochrane using the MESH terms "phantom limb pain" and "psychotherapy", published in the last 10 years, in English and Spanish, finding 49 items. After reviewing the abstracts, 25 articles were excluded for not being related to the objective of the research. Additionally cross references of included articles and literature were reviewed. To describe the psychotherapies used in the management of phantom limb pain, their effectiveness and clinical application reported in the literature. The mechanisms underlying phantom limb pain were initially explained, as were the published studies on the usefulness of some psychotherapies such as mirror visual feedback and immersive virtual reality, visual imagery, desensitization and reprocessing eye movements and hypnosis. The phantom limb pain is a complex syndrome that requires pharmacological and psychotherapeutic intervention. The psychotherapies that have been used the most as adjuvants in the treatment of phantom limb pain are mirror visual feedback, desensitization and reprocessing eye movements, imagery and hypnosis. Studies with more representative samples, specifically randomized trials are required. Copyright © 2016 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Análise da correlação entre síndrome de pseudo-exfoliação e aneurisma de aorta abdominal Analysis of correlation between pseudoexfoliation syndrome and aneurysm of the abdominal aorta

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Paulo de Tarso Ponte Pierre Filho

2004-06-01

Full Text Available OBJETIVO: Examinar a correlação sugerida entre síndrome de pseudo-exfoliação e aneurisma de aorta abdominal. MÉTODOS: Sessenta e cinco pacientes recentemente operados por aneurisma de aorta abdominal e 51 controles com aterosclerose periférica, sem aneurisma, submeteram-se ao exame oftalmológico sob dilatação pupilar para investigar a presença de síndrome de pseudo-exfoliação. RESULTADOS: Não houve diferenças estatisticamente significantes entre a média de idade, distribuição por sexo e raça entre os 2 grupos (p > 0,05. Dois dos 65 pacientes com aneurisma de aorta e um dos 51 controles apresentaram síndrome de pseudo-exfoliação (p = 1,00. CONCLUSÃO: A prevalência de síndrome de pseudo-exfoliação em pacientes operados por aneurisma de aorta abdominal e em pacientes com aterosclerose periférica foi similar. Este achado não confirma a associação proposta entre síndrome de pseudo-exfoliação e aneurisma de aorta abdominal.PURPOSE: To investigate the suggested association between pseudoexfoliation syndrome and aneurysm of the abdominal aorta. METHODS: 65 patients recently operated for abdominal aortic aneurysm and 51 controls with peripheral atherosclerosis, without aneurysm, underwent an ophthalmologic examination under pupillary dilatation to detect the presence of pseudoexfoliation syndrome. RESULTS: There were no significant differences regarding mean age and distribution by gender and race between the groups (p > 0.05. Two of 65 patients with aortic aneurysm and one of 51 controls presented pseudoexfoliation syndrome (p = 1.00. CONCLUSION: The prevalence of pseudoexfoliation syndrome in patients operated for abdominal aortic aneurysm and in patients with peripheral atherosclerosis were similar. This finding does not support the proposed association between pseudoexfoliation syndrome and abdominal aortic aneurysm.

Ultrasonographic measurement of canine aorta and aortic inlet before and after administration of Propofol

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Gh Assadnassab

2008-11-01

Full Text Available Induction of safe anesthesia is an important task in veterinary medicine. One of the drugs used for anesthesia is Propofol. In this study, five healthy German shepherd dogs were selected and standard echocardiographic procedure from the right parasternal axis view conducted to observe the aorta and aortic inlet in B-mode and M-mode display formats before and after anesthesia with 6 mg/kg of Propofol. In the short axis view, the dorso-ventral and transverse diameter of the aorta in B-mode display and in the long axis view, the systolic and diastolic diameter of the aortic inlet in M-mode display were measured. The average dorso-ventral and transverse diameter of aorta in normal dogs was 22.77±1.49 mm and 20.75± 1.34 mm respectively while in anesthetized dogs these figures were 22.02±0.87 mm and 20.64±1.19 mm respectively which were not significantly different from normal dogs. However, the mean diameter of aorta inlet in M-mode display during systole and diastole was 15.62±0.84 mm and 15.31±0.68 mm respectively in normal dogs and for anesthetized animals these figures were 21.60±1.23 mm during systole and 19.70±0.68 mm during diastole which were significantly different compared with the normal dogs.

Primary motor cortex changes after amputation correlate with phantom limb pain and the ability to move the phantom limb

DEFF Research Database (Denmark)

Raffin, Estelle; Richard, Nathalie; Giraux, Pascal

2016-01-01

A substantial body of evidence documents massive reorganization of primary sensory and motor cortices following hand amputation, the extent of which is correlated with phantom limb pain. Many therapies for phantom limb pain are based upon the idea that plastic changes after amputation...... for the maladaptative plasticity model, we demonstrate for the first time that motor capacities of the phantom limb correlate with post-amputation reorganization, and that this reorganization is not limited to the face and hand representations but also includes the proximal upper-limb....

Customized CT angiogram planning for intraoperative transesophageal echography-guided endovascular exclusion of thoracic aorta penetrating ulcer.

Science.gov (United States)

Piazza, Michele; Lupia, Mario; Grego, Franco; Antonello, Michele

2015-04-01

The technique is demonstrated in a 78-year-old man; the preoperative CT angiogram showed a descending thoracic aorta ulcer of 5.9 cm in maximum diameter and 3.8 cm longitudinal extension. A ZTEG-2P-36-127-PF (Cook Medical) single tubular endograft was planned to be deployed. From the preoperative CT angiogram we planned to land 4.7 cm above the midline of the descending thoracic aorta ulcer and 8.0 cm below. In the operating room, under radioscopic vision the centre of the transesophageal echography probe was used as marker to identify the correspondent midline of the descending thoracic aorta ulcer and a centimeter-sized pigtail catheter in the aorta was used to calculate the desired length above and below the ulcer midline. The endograft was introduced and placed in the desired position compared to the transesophageal echography probe and the catheter; under transesophageal echography vision the graft was finally deployed. The CT angiogram at 1 month showed the correct endograft position, descending thoracic aorta ulcer exclusion with no signs of endoleak. In selected cases, this method allows planning in advance safe stent graft positioning and deployment totally assisted by transesophageal echography, with no risk of periprocedural contrast-related renal failure and reduced radiation exposure for the patient and operators. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Effect of different saline chaser volumes and flow rates on intravascular contrast enhancement in CT using a circulation phantom

International Nuclear Information System (INIS)

Behrendt, Florian F.; Bruners, Philipp; Keil, Sebastian; Plumhans, Cedric; Mahnken, Andreas H.; Das, Marco; Ackermann, Diana; Guenther, Rolf W.; Muehlenbruch, Georg

2010-01-01

Purpose: To evaluate the influence of different saline chaser volumes and different saline chaser flow rates on the intravascular contrast enhancement in MDCT. Materials and methods: In a physiological flow phantom contrast medium (120 ml, 300 mgI/ml, Ultravist 300) was administered at a flow rate of 6 ml/s followed by different saline chaser volumes (0, 30, 60 and 90 ml) at the same injection rate or followed by a 30-ml saline chaser at different injection rates (2, 4, 6 and 8 ml/s). Serial CT-scans at a level covering the pulmonary artery, the ascending and the descending aorta replica were obtained. Time-enhancement curves were computed and both pulmonary and aortic peak enhancement and peak time were determined. Results: Compared to contrast medium injection without a saline chaser the pushing with a saline chaser (30, 60, and 90 ml) resulted in a statistically significant increased pulmonary peak enhancement (all p = 0.008) and prolonged peak time (p = 0.032, p = 0.024 and p = 0.008, respectively). Highest aortic peak enhancement values were detected for a saline chaser volume of 30 ml. A saline chaser flow rate of 8 ml/s resulted in the highest pulmonary peak enhancement values compared to flow rates of 2, 4 and 6 ml/s (all p = 0.008). Aortic peak enhancement showed the highest values for a flow rate of 6 ml/s. Conclusion: A saline chaser volume of 30 ml and an injection rate of 6 ml/s are sufficient to best improve vascular contrast enhancement in the pulmonary artery and the aorta in MDCT.

The UF family of reference hybrid phantoms for computational radiation dosimetry

International Nuclear Information System (INIS)

Lee, Choonsik; Lodwick, Daniel; Hurtado, Jorge; Pafundi, Deanna; Williams, Jonathan L; Bolch, Wesley E

2010-01-01

Computational human phantoms are computer models used to obtain dose distributions within the human body exposed to internal or external radiation sources. In addition, they are increasingly used to develop detector efficiencies for in vivo whole-body counters. Two classes of computational human phantoms have been widely utilized for dosimetry calculation: stylized and voxel phantoms that describe human anatomy through mathematical surface equations and 3D voxel matrices, respectively. Stylized phantoms are flexible in that changes to organ position and shape are possible given avoidance of region overlap, while voxel phantoms are typically fixed to a given patient anatomy, yet can be proportionally scaled to match individuals of larger or smaller stature, but of equivalent organ anatomy. Voxel phantoms provide much better anatomical realism as compared to stylized phantoms which are intrinsically limited by mathematical surface equations. To address the drawbacks of these phantoms, hybrid phantoms based on non-uniform rational B-spline (NURBS) surfaces have been introduced wherein anthropomorphic flexibility and anatomic realism are both preserved. Researchers at the University of Florida have introduced a series of hybrid phantoms representing the ICRP Publication 89 reference newborn, 15 year, and adult male and female. In this study, six additional phantoms are added to the UF family of hybrid phantoms-those of the reference 1 year, 5 year and 10 year child. Head and torso CT images of patients whose ages were close to the targeted ages were obtained under approved protocols. Major organs and tissues were segmented from these images using an image processing software, 3D-DOCTOR(TM). NURBS and polygon mesh surfaces were then used to model individual organs and tissues after importing the segmented organ models to the 3D NURBS modeling software, Rhinoceros(TM). The phantoms were matched to four reference datasets: (1) standard anthropometric data, (2) reference

Development of thyroid anthropomorphic phantoms for use in nuclear medicine

International Nuclear Information System (INIS)

Cerqueira, R.A.D.; Maia, A.F.

2014-01-01

The objective of this study was to develop thyroid anthropomorphic phantoms to be used in control tests of medical images in scintillation cameras. The main difference among the phantoms was the neck shape: in the first, called OSCT, it was geometrically shaped, while in the second, called OSAP, it was anthropomorphically shaped. In both phantoms, thyroid gland prototypes, which were made of acrylic and anthropomorphically shaped, were constructed to allow the simulation of a healthy thyroid and of thyroids with hyperthyroidism and hypothyroidism. Images of these thyroid anthropomorphic phantoms were obtained using iodine 131 with an activity of 8.695 MBq. The iodine 131 was chosen because it is widely used in studies of thyroid scintigraphy. The images obtained proved the effectiveness of the phantoms to simulate normal or abnormal thyroids function. These phantoms can be used in medical imaging quality control programs and, also in the training of professionals involved in the analysis of images in nuclear medicine centers. - Highlights: ► Two thyroid phantoms were developed (OSCT and OSAP) with different types of acrylics. ► Thyroid glands were represented anthropomorphically in the both phantoms. ► Different prototypes of thyroid were built of simulate healthy or unhealthy glands. ► Images indicate that anthropomorphic phantoms correctly simulate the thyroid gland

Effects of intraoperative electron irradiation in the dog on cell turnover in intact and surgically-anastomosed aorta and intestine

International Nuclear Information System (INIS)

Sindelar, W.F.; Morrow, B.M.; Travis, E.L.; Tepper, J.; Merkel, A.B.; Kranda, K.; Terrill, R.

1983-01-01

Adults dogs were subjected to laparotomy and intraoperative electron irradiation after division and reanastomosis of aorta or after construction of a blind loop of small intestine having a transverse suture line and an end-to-side anastomosis. Dogs received intraoperative irradiation of both intact and anastomosed aorta or intestine in doses of 0, 2000, 3000, or 4500 rad. Animals were sacrificed at seven days or three months following treatment. At 24 hours prior to sacrifice, dogs received 5 mCi tritiated thymidine intravenously. Irradiated and non-irradiated segments of aorta and small intestine, including intact and anastomotic regions, were analyzed for tritiated thymidine incorporation and were subjected to autoradiography. Incorporation studies showed diminution in tritiated thymidine uptake by irradiated portions of aorta and small intestine, in both intact and anastomotic regions. Autoradiograms revealed that irradiated areas of intact or anastomotic aorta or intestine had diminished labeling of stromal cells, suggesting a lowered cell proliferative capacity of irradiated tissue compared to non-irradiated portions. Inflammatory cells showed similar labeling indices in irradiated and non-irradiated tissues, both intact and surgically-manipulated, suggesting that irradiation does not significantly affect a subsequent local inflammatory response. Radiation-induced decreases in tritiated thymidine incoporation in irradiated aorta and small intestine were generally more marked at seven days than at three months following irradiation, suggesting that radiation-induced depression of cell turnover rates decreases with time

Measurement of TLD Albedo response on various calibration phantoms

International Nuclear Information System (INIS)

Momose, T.; Tsujimura, N.; Shinohara, K.; Ishiguro, H.; Nakamura, T.

1996-01-01

The International Commission on Radiation Units and Measurements (ICRU) has recommended that individual dosemeter should be calibrated on a suitable phantom and has pointed out that the calibration factor of a neutron dosemeter is strongly influenced by the the exact size and shape of the body and the phantom to which the dosemeter is attached. As the principle of an albedo type thermoluminescent personal dosemeter (albedo TLD) is essentially based on a detection of scattered and moderated neutron from a human body, the sensitivity of albedo TLD is strongly influenced by the incident neutron energy and the calibration phantom. (1) Therefore for albedo type thermoluminescent personal dosemeter (albedo TLD), the information of neutron albedo response on the calibration phantom is important for appropriate dose estimation. In order to investigate the effect of phantom type on the reading of the albedo TLD, measurement of the TLD energy response and angular response on some typical calibration phantoms was performed using dynamitron accelerator and 252 Cf neutron source. (author)

Agency over Phantom Limb Enhanced by Short-Term Mirror Therapy.

Science.gov (United States)

Imaizumi, Shu; Asai, Tomohisa; Koyama, Shinichi

2017-01-01

Most amputees experience phantom limb, whereby they feel that the amputated limb is still present. In some cases, these experiences include pain that can be alleviated by "mirror therapy." Mirror therapy consists of superimposing a mirrored image of the moving intact limb onto the phantom limb. This therapy provides a closed loop between the motor command to the amputated limb and its predicted visual feedback. This loop is also involved in the sense of agency, a feeling of controlling one's own body. However, it is unclear how mirror therapy is related to the sense of agency over a phantom limb. Using mirror therapy, we investigated phantom limb pain and the senses of agency and ownership (i.e., a feeling of having one's own body) of the phantom limb. Nine upper-limb amputees, five of whom reported recent phantom limb pain, underwent a single 15-min trial of mirror therapy. Before and after the trial, the participants completed a questionnaire regarding agency, ownership, and pain related to their phantom limb. They reported that the sense of agency over the phantom limb increased following the mirror therapy trial, while the ownership slightly increased but not as much as did the agency. The reported pain did not change; that is, it was comparably mild before and after the trial. These results suggest that short-term mirror therapy can, at least transiently, selectively enhance the sense of agency over a phantom limb, but may not alleviate phantom limb pain.

Technical Note: Characterization of custom 3D printed multimodality imaging phantoms

International Nuclear Information System (INIS)

Bieniosek, Matthew F.; Lee, Brian J.; Levin, Craig S.

2015-01-01

Purpose: Imaging phantoms are important tools for researchers and technicians, but they can be costly and difficult to customize. Three dimensional (3D) printing is a widely available rapid prototyping technique that enables the fabrication of objects with 3D computer generated geometries. It is ideal for quickly producing customized, low cost, multimodal, reusable imaging phantoms. This work validates the use of 3D printed phantoms by comparing CT and PET scans of a 3D printed phantom and a commercial “Micro Deluxe” phantom. This report also presents results from a customized 3D printed PET/MRI phantom, and a customized high resolution imaging phantom with sub-mm features. Methods: CT and PET scans of a 3D printed phantom and a commercial Micro Deluxe (Data Spectrum Corporation, USA) phantom with 1.2, 1.6, 2.4, 3.2, 4.0, and 4.8 mm diameter hot rods were acquired. The measured PET and CT rod sizes, activities, and attenuation coefficients were compared. A PET/MRI scan of a custom 3D printed phantom with hot and cold rods was performed, with photon attenuation and normalization measurements performed with a separate 3D printed normalization phantom. X-ray transmission scans of a customized two level high resolution 3D printed phantom with sub-mm features were also performed. Results: Results show very good agreement between commercial and 3D printed micro deluxe phantoms with less than 3% difference in CT measured rod diameter, less than 5% difference in PET measured rod diameter, and a maximum of 6.2% difference in average rod activity from a 10 min, 333 kBq/ml (9 μCi/ml) Siemens Inveon (Siemens Healthcare, Germany) PET scan. In all cases, these differences were within the measurement uncertainties of our setups. PET/MRI scans successfully identified 3D printed hot and cold rods on PET and MRI modalities. X-ray projection images of a 3D printed high resolution phantom identified features as small as 350 μm wide. Conclusions: This work shows that 3D printed

Technical Note: Characterization of custom 3D printed multimodality imaging phantoms

Energy Technology Data Exchange (ETDEWEB)

Bieniosek, Matthew F. [Department of Electrical Engineering, Stanford University, 350 Serra Mall, Stanford, California 94305 (United States); Lee, Brian J. [Department of Mechanical Engineering, Stanford University, 440 Escondido Mall, Stanford, California 94305 (United States); Levin, Craig S., E-mail: cslevin@stanford.edu [Departments of Radiology, Physics, Bioengineering and Electrical Engineering, Stanford University, 300 Pasteur Dr., Stanford, California 94305-5128 (United States)

2015-10-15

Purpose: Imaging phantoms are important tools for researchers and technicians, but they can be costly and difficult to customize. Three dimensional (3D) printing is a widely available rapid prototyping technique that enables the fabrication of objects with 3D computer generated geometries. It is ideal for quickly producing customized, low cost, multimodal, reusable imaging phantoms. This work validates the use of 3D printed phantoms by comparing CT and PET scans of a 3D printed phantom and a commercial “Micro Deluxe” phantom. This report also presents results from a customized 3D printed PET/MRI phantom, and a customized high resolution imaging phantom with sub-mm features. Methods: CT and PET scans of a 3D printed phantom and a commercial Micro Deluxe (Data Spectrum Corporation, USA) phantom with 1.2, 1.6, 2.4, 3.2, 4.0, and 4.8 mm diameter hot rods were acquired. The measured PET and CT rod sizes, activities, and attenuation coefficients were compared. A PET/MRI scan of a custom 3D printed phantom with hot and cold rods was performed, with photon attenuation and normalization measurements performed with a separate 3D printed normalization phantom. X-ray transmission scans of a customized two level high resolution 3D printed phantom with sub-mm features were also performed. Results: Results show very good agreement between commercial and 3D printed micro deluxe phantoms with less than 3% difference in CT measured rod diameter, less than 5% difference in PET measured rod diameter, and a maximum of 6.2% difference in average rod activity from a 10 min, 333 kBq/ml (9 μCi/ml) Siemens Inveon (Siemens Healthcare, Germany) PET scan. In all cases, these differences were within the measurement uncertainties of our setups. PET/MRI scans successfully identified 3D printed hot and cold rods on PET and MRI modalities. X-ray projection images of a 3D printed high resolution phantom identified features as small as 350 μm wide. Conclusions: This work shows that 3D printed

Technical Note: Characterization of custom 3D printed multimodality imaging phantoms.

Science.gov (United States)

Bieniosek, Matthew F; Lee, Brian J; Levin, Craig S

2015-10-01

Imaging phantoms are important tools for researchers and technicians, but they can be costly and difficult to customize. Three dimensional (3D) printing is a widely available rapid prototyping technique that enables the fabrication of objects with 3D computer generated geometries. It is ideal for quickly producing customized, low cost, multimodal, reusable imaging phantoms. This work validates the use of 3D printed phantoms by comparing CT and PET scans of a 3D printed phantom and a commercial "Micro Deluxe" phantom. This report also presents results from a customized 3D printed PET/MRI phantom, and a customized high resolution imaging phantom with sub-mm features. CT and PET scans of a 3D printed phantom and a commercial Micro Deluxe (Data Spectrum Corporation, USA) phantom with 1.2, 1.6, 2.4, 3.2, 4.0, and 4.8 mm diameter hot rods were acquired. The measured PET and CT rod sizes, activities, and attenuation coefficients were compared. A PET/MRI scan of a custom 3D printed phantom with hot and cold rods was performed, with photon attenuation and normalization measurements performed with a separate 3D printed normalization phantom. X-ray transmission scans of a customized two level high resolution 3D printed phantom with sub-mm features were also performed. Results show very good agreement between commercial and 3D printed micro deluxe phantoms with less than 3% difference in CT measured rod diameter, less than 5% difference in PET measured rod diameter, and a maximum of 6.2% difference in average rod activity from a 10 min, 333 kBq/ml (9 μCi/ml) Siemens Inveon (Siemens Healthcare, Germany) PET scan. In all cases, these differences were within the measurement uncertainties of our setups. PET/MRI scans successfully identified 3D printed hot and cold rods on PET and MRI modalities. X-ray projection images of a 3D printed high resolution phantom identified features as small as 350 μm wide. This work shows that 3D printed phantoms can be functionally equivalent to

Variations in local elastic modulus along the length of the aorta as observed by use of a scanning haptic microscope (SHM).

Science.gov (United States)

Moriwaki, Takeshi; Oie, Tomonori; Takamizawa, Keiichi; Murayama, Yoshinobu; Fukuda, Toru; Omata, Sadao; Kanda, Keiichi; Nakayama, Yasuhide

2011-12-01

Variations in microscopic elastic structures along the entire length of canine aorta were evaluated by use of a scanning haptic microscope (SHM). The total aorta from the aortic arch to the abdominal aorta was divided into 6 approximately equal segments. After embedding the aorta in agar, it was cut into horizontal circumferential segments to obtain disk-like agar portions containing ring-like samples of aorta with flat surfaces (thickness, approximately 1 mm). The elastic modulus and topography of the samples under no-load conditions were simultaneously measured along the entire thickness of the wall by SHM by using a probe with a diameter of 5 μm and a spatial resolution of 2 μm at a rate of 0.3 s/point. The elastic modulus of the wall was the highest on the side of the luminal surface and decreased gradually toward the adventitial side. This tendency was similar to that of the change in the elastin fiber content. During the evaluation of the mid-portion of each tunica media segment, the highest elastic modulus (40.8 ± 3.5 kPa) was identified at the thoracic section of the aorta that had the highest density of elastic fibers. Under no-load conditions, portions of the aorta with high elastin density have a high elastic modulus.

Thoracic aorta 3D hemodynamics in pediatric and young adult patients with bicuspid aortic valve.

Science.gov (United States)

Allen, Bradley D; van Ooij, Pim; Barker, Alex J; Carr, Maria; Gabbour, Maya; Schnell, Susanne; Jarvis, Kelly B; Carr, James C; Markl, Michael; Rigsby, Cynthia; Robinson, Joshua D

2015-10-01

To evaluate the 3D hemodynamics in the thoracic aorta of pediatric and young adult bicuspid aortic valve (BAV) patients. 4D flow MRI was performed in 30 pediatric and young adult BAV patients (age: 13.9 ± 4.4 (range: [3.4, 20.7]) years old, M:F = 17:13) as part of this Institutional Review Board-approved study. Nomogram-based aortic root Z-scores were calculated to assess aortic dilatation and degree of aortic stenosis (AS) severity was assessed on MRI. Data analysis included calculation of time-averaged systolic 3D wall shear stress (WSSsys ) along the entire aorta wall, and regional quantification of maximum and mean WSSsys and peak systolic velocity (velsys ) in the ascending aorta (AAo), arch, and descending aorta (DAo). The 4D flow MRI AAo velsys was also compared with echocardiography peak velocity measurements. There was a positive correlation with both mean and max AAo WSSsys and peak AAo velsys (mean: r = 0.84, P max: r = 0.94, P max: rS  = 0.70, P < 0.001). AAo peak velocity was significantly higher when measured with echo compared with 4D flow MRI (2.1 ± 0.98 m/s versus 1.27 ± 0.49 m/s, P < 0.001). In pediatric and young adult patients with BAV, AS and peak ascending aorta velocity are associated with increased AAo WSS, while aortic dilation, age, and body surface area do not significantly impact AAo hemodynamics. Prospective studies are required to establish the role of WSS as a risk-stratification tool in these patients. © 2015 Wiley Periodicals, Inc.

Thrombosis of abdominal aorta during cisplatin-based chemotherapy of testicular seminoma - a case report

Directory of Open Access Journals (Sweden)

Gehrckens Ralf

2009-12-01

Full Text Available Abstract Background Vascular complications occurring during cisplatin-based chemotherapy of germ cell tumours are inadequately recognized to date. Case Presentation A 49 year old man with advanced seminoma underwent two courses of chemotherapy according to the PEB regimen. Upon restaging, two thrombotic deposits were noted in the descending part of the thoracic aorta and in the infrarenal abdominal aorta, respectively. Although thrombotic plaques caused aortic occlusion of about 30%, no clinical signs of malperfusion of limbs were registered. The patient was placed on anticoagulant therapy. Six months after completion of chemotherapy, thrombotic deposits had completely resolved. In the absence of other predisposing factors, it must be assumed that cisplatin-based chemotherapy represented a strong stimulus for arterial thrombosis in the aorta. Conclusions This is the first case of endo-aortic thrombosis during chemotherapy for testicular germ cell cancer. Providers of chemotherapy must be aware of arterial thrombosis even in young patients with testicular cancer.

"Stent" auto-expansível nas dissecções da aorta tipo B Self-expanding stent in type B dissections of the aorta

Directory of Open Access Journals (Sweden)

Wagner Michael PEREIRA

1999-07-01

Full Text Available O tratamento clínico das dissecções agudas da aorta do tipo B tem mortalidade em torno de 25% menor que a mortalidade cirúrgica. O tratamento cirúrgico das dissecções crônicas também produz uma morbidade e mortalidade elevadas. A utilização de "stents"auto-expansíveis endovasculares pode ser uma nova alternativa no tratamento destas lesões. De abril a dezembro de 1998 foram implantados 15 "stents" endovasculares, 10 em dissecções agudas e 5 em crônicas. A idade dos pacientes variou entre 48 e 75 anos (média=60,53±9,73 anos com 66,6% do sexo masculino. Os pacientes foram submetidos à esternotomia mediana, circulação extracorpórea (CEC com hipotermia profunda (18° - 20°C, parada circulatória total (PCT e perfusão cerebral retrógrada (PCR. A aorta transversa foi incisada e implantado o "stent" na aorta descendente sob auxílio de aortoscopia. Foram analisados os tempos de CEC, pinçamento aórtico, PCT, PCR, reaquecimento, ventilação mecânica, internação, sangramento trans e pós-operatório, reposição sangüínea, gasometria, curva de eventos e sobrevida. A mortalidade hospitalar (30 dias foi de 6,6%; 2 pacientes foram reoperados com 3 e 6 meses após a operação com dissecção da aorta ascendente e aneurisma roto distal ao "stent". Quatorze vêm sendo acompanhados com 1 a 8m de evolução, sendo que 85,7% estão livres de eventos e curva de sobrevida de 93,1%(240 dias. Concluímos que o implante de "stent"intraluminais auto-expansíveis apresentou mortalidade menor na fase aguda da doença (6,6% comparada à nossa experiência anterior com o tratamento clínico (30%. Apesar da amostra ser pequena, o procedimento parece ser promissor e necessita mais acompanhamento.The clinical treatment of acute type B aortic dissection has a mortality of about 25%, therefore, less than surgical mortality. The surgical treatment of chronic dissections also produces a high morbidity and mortality. The use of self

Design of a tracked ultrasound calibration phantom made of LEGO bricks

Science.gov (United States)

Walsh, Ryan; Soehl, Marie; Rankin, Adam; Lasso, Andras; Fichtinger, Gabor

2014-03-01

PURPOSE: Spatial calibration of tracked ultrasound systems is commonly performed using precisely fabricated phantoms. Machining or 3D printing has relatively high cost and not easily available. Moreover, the possibilities for modifying the phantoms are very limited. Our goal was to find a method to construct a calibration phantom from affordable, widely available components, which can be built in short time, can be easily modified, and provides comparable accuracy to the existing solutions. METHODS: We designed an N-wire calibration phantom made of LEGO® bricks. To affirm the phantom's reproducibility and build time, ten builds were done by first-time users. The phantoms were used for a tracked ultrasound calibration by an experienced user. The success of each user's build was determined by the lowest root mean square (RMS) wire reprojection error of three calibrations. The accuracy and variance of calibrations were evaluated for the calibrations produced for various tracked ultrasound probes. The proposed model was compared to two of the currently available phantom models for both electromagnetic and optical tracking. RESULTS: The phantom was successfully built by all ten first-time users in an average time of 18.8 minutes. It cost approximately $10 CAD for the required LEGO® bricks and averaged a 0.69mm of error in the calibration reproducibility for ultrasound calibrations. It is one third the cost of similar 3D printed phantoms and takes much less time to build. The proposed phantom's image reprojections were 0.13mm more erroneous than those of the highest performing current phantom model The average standard deviation of multiple 3D image reprojections differed by 0.05mm between the phantoms CONCLUSION: It was found that the phantom could be built in less time, was one third the cost, compared to similar 3D printed models. The proposed phantom was found to be capable of producing equivalent calibrations to 3D printed phantoms.

In vitro vasorelaxation mechanisms of bioactive compounds extracted from Hibiscus sabdariffa on rat thoracic aorta

Science.gov (United States)

Sarr, Mamadou; Ngom, Saliou; Kane, Modou O; Wele, Alassane; Diop, Doudou; Sarr, Bocar; Gueye, Lamine; Andriantsitohaina, Ramaroson; Diallo, Aminata S

2009-01-01

Background In this study, we suggested characterizing the vasodilator effects and the phytochemical characteristics of a plant with food usage also used in traditional treatment of arterial high blood pressure in Senegal. Methods Vascular effects of crude extract of dried and powdered calyces of Hibiscus sabdariffa were evaluated on isolated thoracic aorta of male Wistar rats on organ chambers. The crude extract was also enriched by liquid-liquid extraction. The various cyclohexane, dichloromethane, ethyl acetate, butanol extracts obtained as well as the residual marc were subjected to Sephadex LH-20 column chromatography. The different methanolic eluate fractions were then analyzed by Thin Layer (TLC) and High Performance Liquid Chromatography (HPLC) and their vascular effects also evaluated. Results The H. Sabdariffa crude extract induced mainly endothelium-dependent relaxant effects. The endothelium-dependent relaxations result from NOS activation and those who not dependent to endothelium from activation of smooth muscle potassium channels. The phytochemical analysis revealed the presence of phenolic acids in the ethyl acetate extract and anthocyans in the butanolic extract. The biological efficiency of the various studied extracts, in term of vasorelaxant capacity, showed that: Butanol extract > Crude extract > Residual marc > Ethyl acetate extract. These results suggest that the strong activity of the butanolic extract is essentially due to the presence of anthocyans found in its fractions 43-67. Conclusion These results demonstrate the vasodilator potential of hibiscus sabdariffa and contribute to his valuation as therapeutic alternative. PMID:19883513

Estimation of prenatal aorta intima-media thickness in ultrasound examination

Science.gov (United States)

Veronese, Elisa; Poletti, Enea; Cosmi, Erich; Grisan, Enrico

2012-03-01

Prenatal events such as intrauterine growth restriction have been shown to be associated with an increased thickness of abdominal aorta in the fetus. Therefore the measurement of abdominal aortic intima-media thickness (aIMT) has been recently considered a sensitive marker of artherosclerosis risk. To date measure of aortic diameter and of aIMT has been performed manually on US fetal images, thus being susceptible to intra- and inter- operator variability. This work introduces an automatic algorithm that identifies abdominal aorta and estimates its diameter and aIMT from videos recorded during routine third trimester ultrasonographic fetal biometry. Firstly, in each frame, the algorithm locates and segments the region corresponding to aorta by means of an active contour driven by two different external forces: a static vector field convolution force and a dynamic pressure force. Then, in each frame, the mean diameter of the vessel is computed, to reconstruct the cardiac cycle: in fact, we expect the diameter to have a sinusoidal trend, according to the heart rate. From the obtained sinusoid, we identify the frames corresponding to the end diastole and to the end systole. Finally, in these frames we assess the aIMT. According to its definition, we consider as aIMT the distance between the leading edge of the blood-intima interface, and the leading edge of the media-adventitia interface on the far wall of the vessel. The correlation between end-diastole and end-systole aIMT automatic and manual measures is 0.90 and 0.84 respectively.

NURBS-based 3-d anthropomorphic computational phantoms for radiation dosimetry applications

International Nuclear Information System (INIS)

Lee, Choonsik; Lodwick, Daniel; Lee, Choonik; Bolch, Wesley E.

2007-01-01

Computational anthropomorphic phantoms are computer models used in the evaluation of absorbed dose distributions within the human body. Currently, two classes of the computational phantoms have been developed and widely utilised for dosimetry calculation: (1) stylized (equation-based) and (2) voxel (image-based) phantoms describing human anatomy through the use of mathematical surface equations and 3-D voxel matrices, respectively. However, stylized phantoms have limitations in defining realistic organ contours and positioning as compared to voxel phantoms, which are themselves based on medical images of human subjects. In turn, voxel phantoms that have been developed through medical image segmentation have limitations in describing organs that are presented in low contrast within either magnetic resonance or computed tomography image. The present paper reviews the advantages and disadvantages of these existing classes of computational phantoms and introduces a hybrid approach to a computational phantom construction based on non-uniform rational B-Spline (NURBS) surface animation technology that takes advantage of the most desirable features of the former two phantom types. (authors)

Regional heating patterns of RF hyperthermia applicators in phantoms

International Nuclear Information System (INIS)

Kantor, G.; Ruggera, P.S.; Samulski, T.V.

1984-01-01

An elliptical phantom (20 cm by 30 cm cross-section and 40 cm long) with a 1 cm fat layer filled with muscle material was used to compare the induced heating patterns of the NCDRH helical coil, a Henry Medical Magnetrode coil, both with a diameter of 35.6 cm, and the BSD Annular Phased Array System (APAS). Temperature profiles were taken in the midplane cross-sectional slice along the major and minor axes of the phantom. These profiles were measured with a Vitek thermistor probe and the associated specific absorption rates (SAR) were determined from this data. SAR curves for each applicator were obtained along the major and minor axes of the phantom. The depths of heating of the Magnetrode applicator are considerably smaller than those for the helical applicator. Heating patterns for the APAS can be highly variable and asymmetric depending on the frequency of operation and the location of the phantom within the APAS aperture. While the APAS requires a water bolus for good coupling, the NCDRH and Magnetrode coils need only to be air coupled for good phantom coupling. Both the helical applicator and APAS can provide significant heating in the central region of the phantom. However, the heating of the helical coil does not critically depend on the phantom loading

Surface-enhanced Raman spectroscopic monitor of triglyceride hydrolysis in a skin pore phantom

Science.gov (United States)

Weldon, Millicent K.; Morris, Michael D.

1999-04-01

Bacterial hydrolysis of triglycerides is followed in a sebum probe phantom by microprobe surface-enhanced Raman scattering (SERS) spectroscopy. The phantom consists of a purpose-built syringe pump operating at physiological flow rates connected to a 300 micron i.d. capillary. We employ silicon substrate SERS microprobes to monitor the hydrolysis products. The silicon support allows some tip flexibility that makes these probes ideal for insertion into small structures. Propionibacterium acnes are immobilized on the inner surface of the capillary. These bacteria hydrolyze the triglycerides in a model sebum emulsion flowing through the capillary. The transformation is followed in vitro as changes in the SERS caused by hydrolysis of triglyceride to fatty acid. The breakdown products consists of a mixture of mono- and diglycerides and their parent long chain fatty acids. The fatty acids adsorb as their carboxylates and can be readily identified by their characteristic spectra. The technique can also confirm the presence of bacteria by detection of short chain carboxylic acids released as products of glucose fermentation during the growth cycle of these cells. Co-adsorption of propionate is observed. Spatial localization of the bacteria is obtained by ex-situ line imaging of the probe.

Onze anos de experiência com emprego do anel intraluminal para tratamento das doenças da aorta

Directory of Open Access Journals (Sweden)

BERNARDES Rodrigo de Castro

1999-01-01

Full Text Available O tratamento cirúrgico das doenças da aorta é geralmente acompanhado de altas taxas de morbimortalidade. O paciente que tem média de idade avançada geralmente é apresentado ao cirurgião em estado grave, com má condição nutricional, muitas vezes com alterações em vários órgãos e sistemas causados pela própria doença aguda. A correção convencional exige técnicas coadjuvantes complexas e agressivas como a circulação extracorpórea prolongada, hipotermia profunda, parada circulatória total além de prolongados tempos de pinçamento de aorta. Na tentativa de reduzir a agressão cirúrgica no paciente já intensamente debilitado pela própria doença, desenvolvemos, em 1988, um anel intraluminal (1, 2 que tem medidas projetadas e experimentadas para facilitar a sua manipulação e anastomose, proporcionando uma diminuição acentuada no tempo de operação, tempo de CEC, tempo de pinçamento de aorta, excluindo muitas vezes a circulação extracorpórea e a hipotermia, obtendo uma anastomose fácil, rápida, segura e hemostática. Entre março de 1988 e janeiro de 1999, 432 pacientes foram submetidos a tratamento cirúrgico de dissecções ou aneurismas da aorta em nosso Serviço. Em 328 pacientes empregamos o anel intraluminal como técnica de anastomose. Usamos 489 anéis. Cento e vinte e cinco pacientes eram portadores de dissecção aguda de aorta do tipo A, 29 eram portadores de dissecção aguda de aorta do tipo B, 81 de aneurisma de aorta ascendente, 8 de aneurisma de arco aórtico, 28 pacientes eram portadores de aneurisma de aorta torácica descendente, 17 eram portadores de aneurisma toracoabdominal e 40 pacientes de aneurisma de aorta abdominal infra-renal. A mortalidade global foi de 13,41%. O seguimento ambulatorial destes pacientes variou de 11 anos a 25 dias. A curva actuarial de sobrevivência em 11 anos mostra 67,3%. Em nenhum caso observamos as complicações descritas na literatura, como embolia, formação de

Hypergravity and multiple reflections in wave propagation in the aorta

NARCIS (Netherlands)

Kroot, J.M.B.; Giannopapa, C.G.

2013-01-01

Hypergravity and gravity changes encountered in, e.g., airplanes, rollercoasters, and spaceflight can result in headaches or loss of consciousness due to decreased cerebral blood flow. This paper describes the effect of hypergravity and gravity changes on the pressure in the aorta and the distension

Phantom dark ghost in Einstein-Cartan gravity

Energy Technology Data Exchange (ETDEWEB)

Chang, Yu-Chiao [National Taiwan University, Department of Physics, Taipei (China); National Taiwan University, LeCosPA, Taipei (China); Bouhmadi-Lopez, Mariam [University of the Basque Country UPV/EHU, Department of Theoretical Physics, P.O. Box 644, Bilbao (Spain); Basque Foundation for Science, IKERBASQUE, Bilbao (Spain); Chen, Pisin [National Taiwan University, Department of Physics, Taipei (China); National Taiwan University, LeCosPA, Taipei (China); National Taiwan University, Graduate Institute of Astrophysics, Taipei (China); SLAC National Accelerator Laboratory, Stanford University, Kavli Institute for Particle Astrophysics and Cosmology, Stanford, CA (United States)

2017-05-15

A class of dynamical dark energy models is constructed through an extended version of fermion fields corresponding to phantom dark ghost spinors, which are spin 1/2 with mass dimension 1. We find that if these spinors interact with torsion fields in a homogeneous and isotropic universe, then it does not imply any future dark energy singularity or any abrupt event, though the fermion has a negative kinetic energy. In fact, the equation of state of this dark energy model will asymptotically approach the value w = -1 from above without crossing the phantom divide and inducing therefore a de Sitter state. Consequently, we expect the model to be stable because no real phantom fields will be created. At late time, the torsion fields will vanish as the corresponding phantom dark ghost spinors dilute. As would be expected, intuitively, this result is unaffected by the presence of cold dark matter although the proof is not as straightforward as in general relativity. (orig.)

Magnetoencephalography Phantom Comparison and Validation: Hospital Universiti Sains Malaysia (HUSM) Requisite.

Science.gov (United States)

Omar, Hazim; Ahmad, Alwani Liyan; Hayashi, Noburo; Idris, Zamzuri; Abdullah, Jafri Malin

2015-12-01

Magnetoencephalography (MEG) has been extensively used to measure small-scale neuronal brain activity. Although it is widely acknowledged as a sensitive tool for deciphering brain activity and source localisation, the accuracy of the MEG system must be critically evaluated. Typically, on-site calibration with the provided phantom (Local phantom) is used. However, this method is still questionable due to the uncertainty that may originate from the phantom itself. Ideally, the validation of MEG data measurements would require cross-site comparability. A simple method of phantom testing was used twice in addition to a measurement taken with a calibrated reference phantom (RefPhantom) obtained from Elekta Oy of Helsinki, Finland. The comparisons of two main aspects were made in terms of the dipole moment (Qpp) and the difference in the dipole distance from the origin (d) after the tests of statistically equal means and variance were confirmed. The result of Qpp measurements for the LocalPhantom and RefPhantom were 978 (SD24) nAm and 988 (SD32) nAm, respectively, and were still optimally within the accepted range of 900 to 1100 nAm. Moreover, the shifted d results for the LocalPhantom and RefPhantom were 1.84 mm (SD 0.53) and 2.14 mm (SD 0.78), respectively, and these values were below the maximum acceptance range of within 5.0 mm of the nominal dipole location. The Local phantom seems to outperform the reference phantom as indicated by the small standard error of the former (SE 0.094) compared with the latter (SE 0.138). The result indicated that HUSM MEG system was in excellent working condition in terms of the dipole magnitude and localisation measurements as these values passed the acceptance limits criteria of the phantom test.

Experimental and computational development of a natural breast phantom for dosimetry studies

International Nuclear Information System (INIS)

Nogueira, Luciana B.; Campos, Tarcisio P.R.

2013-01-01

This paper describes the experimental and computational development of a natural breast phantom, anthropomorphic and anthropometric for studies in dosimetry of brachytherapy and teletherapy of breast. The natural breast phantom developed corresponding to fibroadipose breasts of women aged 30 to 50 years, presenting radiographically medium density. The experimental breast phantom was constituted of three tissue-equivalents (TE's): glandular TE, adipose TE and skin TE. These TE's were developed according to chemical composition of human breast and present radiological response to exposure. Completed the construction of experimental breast phantom this was mounted on a thorax phantom previously developed by the research group NRI/UFMG. Then the computational breast phantom was constructed by performing a computed tomography (CT) by axial slices of the chest phantom. Through the images generated by CT a computational model of voxels of the thorax phantom was developed by SISCODES computational program, being the computational breast phantom represented by the same TE's of the experimental breast phantom. The images generated by CT allowed evaluating the radiological equivalence of the tissues. The breast phantom is being used in studies of experimental dosimetry both in brachytherapy as in teletherapy of breast. Dosimetry studies by MCNP-5 code using the computational model of the phantom breast are in progress. (author)

Diagnostic and therapy of acute thoracic aortic diseases; Diagnostik und Therapie akuter Erkrankungen der thorakalen Aorta

Energy Technology Data Exchange (ETDEWEB)

Schotten, Sebastian; Pitton, Michael B. [Universitaetsmedizin Mainz Univ. (Germany). Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie

2017-09-15

Acute diseases of the thoracic aorta represent a relatively rare but life threatening spectrum of pathologies. The non-traumatic diseases are usually summarized by the term ''acute aortic syndrome''. A timely diagnosis and initiation of therapy are cornerstones for the patient outcome. CT has become the standard imaging procedure due do its widespread availability and excellent sensitivity. Furthermore, CT is able to discriminate the variants of acute aortic diseases and to detect the wide spectrum of complications. The volumetric CT dataset is also the basis for planning of interventional procedures. Open surgical repair still represents the standard of care for acute pathologies of the ascending aorta while endovascular therapy, due to minimally invasive character and good outcome, has replaced open surgery in most cases of complicated lesions of the descending aorta.

Descending thoracic aorta dissection associated with esophageal carcinoma

Directory of Open Access Journals (Sweden)

Kaushik Saha

2013-01-01

Full Text Available The association of aortic dissection with a malignancy is a rare finding and previous reports are usually those of primary aortic sarcomas. A 45-year-old male presented to us with chest pain and dysphagia for 1 month with a background history of obstructive airway disease and uncontrolled hypertension. In this report we present a case of typical descending aorta dissection with associated esophageal carcinoma.

Vasodilator Activity of the Essential Oil from Aerial Parts of Pectis brevipedunculata and Its Main Constituent Citral in Rat Aorta

Directory of Open Access Journals (Sweden)

Gisele Zapata-Sudo

2013-03-01

Full Text Available The essential oil of Pectis brevipedunculata (EOPB, a Brazilian ornamental aromatic grass, is characterized by its high content of citral (81.9%: neral 32.7% and geranial 49.2%, limonene (4.7% and α-pinene (3.4%. Vasodilation induced by EOPB and isolated citral was investigated in pre-contracted vascular smooth muscle, using thoracic aorta from Wistar Kyoto (WKY rats which was prepared for isometric tension recording. EOPB promoted intense relaxation of endothelium-intact and denuded aortic rings with the concentration to induce 50% of the maximal relaxation (IC50 of 0.044% ± 0.006% and 0.093% ± 0.015% (p 0.05. In endothelium-intact aorta, EOPB-induced vasorelaxation was significantly reduced by L-NAME, a nitric oxide synthase inhibitor. The vasodilator activity of citral was increased in the KCl-contracted aorta and citral attenuated the contracture elicited by Ca2+ in depolarized aorta. EOPB and citral elicited vasorelaxation on thoracic aorta by affecting the NO/cyclic GMP pathway and the calcium influx through voltage-dependent L-type Ca2+ channels, respectively.

Vasodilator activity of the essential oil from aerial parts of Pectis brevipedunculata and its main constituent citral in rat aorta.

Science.gov (United States)

Pereira, Sharlene Lopes; Marques, André Mesquita; Sudo, Roberto Takashi; Kaplan, Maria Auxiliadora Coelho; Zapata-Sudo, Gisele

2013-03-07

The essential oil of Pectis brevipedunculata (EOPB), a Brazilian ornamental aromatic grass, is characterized by its high content of citral (81.9%: neral 32.7% and geranial 49.2%), limonene (4.7%) and α-pinene (3.4%). Vasodilation induced by EOPB and isolated citral was investigated in pre-contracted vascular smooth muscle, using thoracic aorta from Wistar Kyoto (WKY) rats which was prepared for isometric tension recording. EOPB promoted intense relaxation of endothelium-intact and denuded aortic rings with the concentration to induce 50% of the maximal relaxation (IC50) of 0.044% ± 0.006% and 0.093% ± 0.015% (p 0.05). In endothelium-intact aorta, EOPB-induced vasorelaxation was significantly reduced by L-NAME, a nitric oxide synthase inhibitor. The vasodilator activity of citral was increased in the KCl-contracted aorta and citral attenuated the contracture elicited by Ca2+ in depolarized aorta. EOPB and citral elicited vasorelaxation on thoracic aorta by affecting the NO/cyclic GMP pathway and the calcium influx through voltage-dependent L-type Ca2+ channels, respectively.

Aneurismas e dissecções da aorta: progresso nos resultados imediatos do tratamento cirúrgico

Directory of Open Access Journals (Sweden)

FONTES Ronaldo D.

1998-01-01

Full Text Available Após 1989, introduzimos algumas alterações no tratamento cirúrgico dos aneurismas e dissecções da aorta, em nosso Serviço, entre elas maior rapidez no diagnóstico, uso de parada circulatória, hipotermia profunda, parada circulatória total, monitorização hemodinâmica, controle dos distúrbios de coagulação, controle da pressão liquórica, implantação das artérias intercostais. Entre janeiro de 1980 e julho de 1994, 520 pacientes foram submetidos a tratamento cirúrgico de aneurismas ou dissecções da aorta, de forma consecutiva e não selecionados. Os pacientes foram divididos em três grupos, de acordo com o diagnóstico: ? Aneurisma de aorta ascendente (AAAS ? Aneurisma de arco aórtico (AAAO ? Dissecção aguda da aorta tipos I e II (DAAO I e II Nos três grupos, a mortalidade foi significativamente inferior para pacientes operados no período após 1989. Variáveis preditivas de mortalidade para AAAS foram: complicações pulmonares (p = 0,0210, renais (p = 0,0310, neurológicas (p < 0,0001. Para DAAO I e II, a hipertensão arterial (p < 0,0001, complicações cardíacas (p < 0,0001, neurológicas (p < 0,0001, renais (p < 0,0001 e a rotura (p < 0,0001 foram preditivas de óbito, e para AAAO foram as variáveis: idade (p = 0,0001 e complicações renais (p = 0,0015. Os autores concluem que as modificações introduzidas no método de tratamento cirúrgico dos aneurismas e dissecções da aorta contribuíram significativamente para a melhora dos resultados.

Evaluation of DQA for tomography using 3D volumetric phantom

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Uk [Dept. of Radiation Oncology, Catholic University of Incheon St. Mary' s Hospital, Incheon (Korea, Republic of); Kim, Jeong Koo [Dept. of Radiological Science, Hanseo University, Seosan (Korea, Republic of)

2016-12-15

The study investigates the necessity of 3 dimensional dose distribution evaluation instead of point dose and 2 dimensional dose distribution evaluation. Treatment plans were generated on the RANDO phantom to measure the precise dose distribution of the treatment site 0.5, 1, 1.5, 2, 2.5, 3 cm with the prescribed dose; 1,200 cGy, 5 fractions. Gamma analysis (3%/3 mm, 2%/2 mm) of dose distribution was evaluated with gafchromic EBT2 film and ArcCHECK phantom. The average error of absolute dose was measured at 0.76±0.59% and 1.37±0.76% in cheese phantom and ArcCHECK phantom respectively. The average passing ratio for 3%/3 mm were 97.72±0.02% and 99.26±0.01% in gafchromic EBT2 film and ArcCHECK phantom respectively. The average passing ratio for 2%/2 mm were 94.21±0.02% and 93.02±0.01% in gafchromic EBT2 film and ArcCHECK phantom respectively. There was a more accurate dose distribution of 3D volume phantom than cheese phantom in patients DQA using tomotherapy. Therefor it should be evaluated simultaneously 3 dimensional dose evaluation on target and peripheral area in rotational radiotherapy such as tomotherapy.

Microsurgical Bypass Training Rat Model, Part 1: Technical Nuances of Exposure of the Aorta and Iliac Arteries.

Science.gov (United States)

Tayebi Meybodi, Ali; Lawton, Michael T; Mokhtari, Pooneh; Yousef, Sonia; Gandhi, Sirin; Benet, Arnau

2017-11-01

Animal models using rodents are frequently used for practicing microvascular anastomosis-an essential technique in cerebrovascular surgery. However, safely and efficiently exposing rat's target vessels is technically difficult. Such difficulty may lead to excessive hemorrhage and shorten animal survival. This limits the ability to perform multiple anastomoses on a single animal and may increase the overall training time and costs. We report our model for microsurgical bypass training in rodents in 2 consecutive articles. In part 1, we describe the technical nuances for a safe and efficient exposure of the rat abdominal aorta and common iliac arteries (CIAs) for bypass. Over a 2-year period, 50 Sprague-Dawley rats underwent inhalant anesthesia for practicing microvascular anastomosis on the abdominal aorta and CIAs. Lessons learned regarding the technical nuances of vessel exposure were recorded. Several technical nuances were important for avoiding intraoperative bleeding and preventing animal demise while preparing an adequate length of vessels for bypass. The most relevant technical nuances include (1) generous subcutaneous dissection; (2) use of cotton swabs for the blunt dissection of the retroperitoneal fat; (3) combination of sharp and blunt dissection to isolate the aorta and iliac arteries from the accompanying veins; (4) proper control of the posterior branches of the aorta; and (5) efficient division and mobilization of the left renal pedicle. Applying the aforementioned technical nuances enables safe and efficient preparation of the rat abdominal aorta and CIAs for microvascular anastomosis. Copyright © 2017 Elsevier Inc. All rights reserved.

Thoracic aorta calcification but not inflammation is associated with increased cardiovascular disease risk: results of the CAMONA study

Energy Technology Data Exchange (ETDEWEB)

Blomberg, Bjoern A. [Odense University Hospital, Department of Nuclear Medicine, Odense C (Denmark); University Medical Center Utrecht, Department of Radiology and Nuclear Medicine, Utrecht (Netherlands); Jong, Pim A. de; Lam, Marnix G.E.; Mali, Willem P.T.M. [University Medical Center Utrecht, Department of Radiology and Nuclear Medicine, Utrecht (Netherlands); Thomassen, Anders [Odense University Hospital, Department of Nuclear Medicine, Odense C (Denmark); Vach, Werner [University Medical Center Freiburg, Clinical Epidemiology, Institute of Medical Biometry and Medical Informatics, Freiburg (Germany); Olsen, Michael H. [Odense University Hospital, The Cardiovascular and Metabolic Preventive Clinic, Department of Endocrinology, Center for Individualized Medicine in Arterial Diseases, Odense (Denmark); Narula, Jagat [Mount Sinai Hospital, Icahn School of Medicine, New York, NY (United States); Alavi, Abass [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Hoeilund-Carlsen, Poul F. [Odense University Hospital, Department of Nuclear Medicine, Odense C (Denmark); University of Southern Denmark, Institute of Clinical Research, Odense (Denmark)

2017-02-15

Arterial inflammation and vascular calcification are regarded as early prognostic markers of cardiovascular disease (CVD). In this study we investigated the relationship between CVD risk and arterial inflammation ({sup 18}F-FDG PET/CT imaging), vascular calcification metabolism (Na{sup 18}F PET/CT imaging), and vascular calcium burden (CT imaging) of the thoracic aorta in a population at low CVD risk. Study participants underwent blood pressure measurements, blood analyses, and {sup 18}F-FDG and Na{sup 18}F PET/CT imaging. In addition, the 10-year risk for development of CVD, based on the Framingham risk score (FRS), was estimated. CVD risk was compared across quartiles of thoracic aorta {sup 18}F-FDG uptake, Na{sup 18}F uptake, and calcium burden on CT. A total of 139 subjects (52 % men, mean age 49 years, age range 21 - 75 years, median FRS 6 %) were evaluated. CVD risk was, on average, 3.7 times higher among subjects with thoracic aorta Na{sup 18}F uptake in the highest quartile compared with those in the lowest quartile of the distribution (15.5 % vs. 4.2 %; P < 0.001). CVD risk was on average, 3.7 times higher among subjects with a thoracic aorta calcium burden on CT in the highest quartile compared with those in the lowest two quartiles of the distribution (18.0 % vs. 4.9 %; P < 0.001). CVD risk was similar in subjects in all quartiles of thoracic aorta {sup 18}F-FDG uptake. Our findings indicate that an unfavourable CVD risk profile is associated with marked increases in vascular calcification metabolism and vascular calcium burden of the thoracic aorta, but not with arterial inflammation. (orig.)

The Phantom Menace

DEFF Research Database (Denmark)

Vium, Christian

2013-01-01

as a phantom menace, which asserts itself through a form of omnipresent fear, nurtured by an inherent opaqueness. As this fundamental fear progressively permeates the nomadic landscape, it engenders a recasting of mobile strategies among the nomadic pastoralist groups who inhabit the interstitial desert spaces....

Simultaneous calibration phantom commission and geometry calibration in cone beam CT

Science.gov (United States)

Xu, Yuan; Yang, Shuai; Ma, Jianhui; Li, Bin; Wu, Shuyu; Qi, Hongliang; Zhou, Linghong

2017-09-01

Geometry calibration is a vital step for describing the geometry of a cone beam computed tomography (CBCT) system and is a prerequisite for CBCT reconstruction. In current methods, calibration phantom commission and geometry calibration are divided into two independent tasks. Small errors in ball-bearing (BB) positioning in the phantom-making step will severely degrade the quality of phantom calibration. To solve this problem, we propose an integrated method to simultaneously realize geometry phantom commission and geometry calibration. Instead of assuming the accuracy of the geometry phantom, the integrated method considers BB centers in the phantom as an optimized parameter in the workflow. Specifically, an evaluation phantom and the corresponding evaluation contrast index are used to evaluate geometry artifacts for optimizing the BB coordinates in the geometry phantom. After utilizing particle swarm optimization, the CBCT geometry and BB coordinates in the geometry phantom are calibrated accurately and are then directly used for the next geometry calibration task in other CBCT systems. To evaluate the proposed method, both qualitative and quantitative studies were performed on simulated and realistic CBCT data. The spatial resolution of reconstructed images using dental CBCT can reach up to 15 line pair cm-1. The proposed method is also superior to the Wiesent method in experiments. This paper shows that the proposed method is attractive for simultaneous and accurate geometry phantom commission and geometry calibration.

Ultrasound-enhanced delivery of targeted echogenic liposomes in a novel ex vivo mouse aorta model.

Science.gov (United States)

Hitchcock, Kathryn E; Caudell, Danielle N; Sutton, Jonathan T; Klegerman, Melvin E; Vela, Deborah; Pyne-Geithman, Gail J; Abruzzo, Todd; Cyr, Peppar E P; Geng, Yong-Jian; McPherson, David D; Holland, Christy K

2010-06-15

The goal of this study was to determine whether targeted, Rhodamine-labeled echogenic liposomes (Rh-ELIP) containing nanobubbles could be delivered to the arterial wall, and whether 1-MHz continuous wave ultrasound would enhance this delivery profile. Aortae excised from apolipoprotein-E-deficient (n=8) and wild-type (n=8) mice were mounted in a pulsatile flow system through which Rh-ELIP were delivered in a stream of bovine serum albumin. Half the aortae from each group were treated with 1-MHz continuous wave ultrasound at 0.49 MPa peak-to-peak pressure, and half underwent sham exposure. Ultrasound parameters were chosen to promote stable cavitation and avoid inertial cavitation. A broadband hydrophone was used to monitor cavitation activity. After treatment, aortic sections were prepared for histology and analyzed by an individual blinded to treatment conditions. Delivery of Rh-ELIP to the vascular endothelium was observed, and sub-endothelial penetration of Rh-ELIP was present in five of five ultrasound-treated aortae and was absent in those not exposed to ultrasound. However, the degree of penetration in the ultrasound-exposed aortae was variable. There was no evidence of ultrasound-mediated tissue damage in any specimen. Ultrasound-enhanced delivery within the arterial wall was demonstrated in this novel model, which allows quantitative evaluation of therapeutic delivery. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Constriction of juxta-ductal aorta and rapid progression of obstruction in a newborn

International Nuclear Information System (INIS)

Awasthy, Neeraj; Tomar, Munesh; Radhakrishnan, Sitaraman; Iyer, Krishna Subramoney

2010-01-01

A 13-day-old baby girl presenting with features of congestive cardiac failure was found to have coarctation of the aorta (CoA) and patent ductus arteriosus (PDA) by echocardiography. Doppler spectral display revealed moderate CoA. Echocardiogram, 12 hours later, showed severe juxtaductal aortic coarctation with spontaneous closure of PDA. This case emphasises the need to keep a close watch on the progress of CoA in the neonatal period, even if the duct has narrowed to a small size thus demonstrating the role of constriction of juxtaductal aorta in pathogenesis of coaractation. Closure of even asmall PDA can cause acute progression CoA in the presence of posterior shelf

Anatomic radiological study of transverse diameter of abdominal aorta by computerized tomography

International Nuclear Information System (INIS)

Ures, S.

1984-01-01

The transverse diameter of abdominal aorta by computerized tomography is studied. The purpose is establish the frequent standard diameters and then diagnose early pathologies, mainly aneurisms. (M.A.C.) [pt

Phantom energy accretion onto black holes in a cyclic universe

International Nuclear Information System (INIS)

Sun Chengyi

2008-01-01

Black holes pose a serious problem in cyclic or oscillating cosmology. It is speculated that, in the cyclic universe with phantom turnarounds, black holes will be torn apart by phantom energy prior to turnaround before they can create any problems. In this paper, using the mechanism of phantom accretion onto black holes, we find that black holes do not disappear before phantom turnaround. But the remanent black holes will not cause any problems due to Hawking evaporation.

Detection of thoracic vascular structures by electrical impedance tomography: a systematic assessment of prominence peak analysis of impedance changes.

Science.gov (United States)

Wodack, K H; Buehler, S; Nishimoto, S A; Graessler, M F; Behem, C R; Waldmann, A D; Mueller, B; Böhm, S H; Kaniusas, E; Thürk, F; Maerz, A; Trepte, C J C; Reuter, D A

2018-02-28

Electrical impedance tomography (EIT) is a non-invasive and radiation-free bedside monitoring technology, primarily used to monitor lung function. First experimental data shows that the descending aorta can be detected at different thoracic heights and might allow the assessment of central hemodynamics, i.e. stroke volume and pulse transit time. First, the feasibility of localizing small non-conductive objects within a saline phantom model was evaluated. Second, this result was utilized for the detection of the aorta by EIT in ten anesthetized pigs with comparison to thoracic computer tomography (CT). Two EIT belts were placed at different thoracic positions and a bolus of hypertonic saline (10 ml, 20%) was administered into the ascending aorta while EIT data were recorded. EIT images were reconstructed using the GREIT model, based on the individual's thoracic contours. The resulting EIT images were analyzed pixel by pixel to identify the aortic pixel, in which the bolus caused the highest transient impedance peak in time. In the phantom, small objects could be located at each position with a maximal deviation of 0.71 cm. In vivo, no significant differences between the aorta position measured by EIT and the anatomical aorta location were obtained for both measurement planes if the search was restricted to the dorsal thoracic region of interest (ROIs). It is possible to detect the descending aorta at different thoracic levels by EIT using an intra-aortic bolus of hypertonic saline. No significant differences in the position of the descending aorta on EIT images compared to CT images were obtained for both EIT belts.

Construction of average adult Japanese voxel phantoms for dose assessment

International Nuclear Information System (INIS)

Sato, Kaoru; Takahashi, Fumiaki; Satoh, Daiki; Endo, Akira

2011-12-01

The International Commission on Radiological Protection (ICRP) adopted the adult reference voxel phantoms based on the physiological and anatomical reference data of Caucasian on October, 2007. The organs and tissues of these phantoms were segmented on the basis of ICRP Publication 103. In future, the dose coefficients for internal dose and dose conversion coefficients for external dose calculated using the adult reference voxel phantoms will be widely used for the radiation protection fields. On the other hand, the body sizes and organ masses of adult Japanese are generally smaller than those of adult Caucasian. In addition, there are some cases that the anatomical characteristics such as body sizes, organ masses and postures of subjects influence the organ doses in dose assessment for medical treatments and radiation accident. Therefore, it was needed to use human phantoms with average anatomical characteristics of Japanese. The authors constructed the averaged adult Japanese male and female voxel phantoms by modifying the previously developed high-resolution adult male (JM) and female (JF) voxel phantoms. It has been modified in the following three aspects: (1) The heights and weights were agreed with the Japanese averages; (2) The masses of organs and tissues were adjusted to the Japanese averages within 10%; (3) The organs and tissues, which were newly added for evaluation of the effective dose in ICRP Publication 103, were modeled. In this study, the organ masses, distances between organs, specific absorbed fractions (SAFs) and dose conversion coefficients of these phantoms were compared with those evaluated using the ICRP adult reference voxel phantoms. This report provides valuable information on the anatomical and dosimetric characteristics of the averaged adult Japanese male and female voxel phantoms developed as reference phantoms of adult Japanese. (author)

Coil embolization of an anastomotic leak after ascending aorta replacement

DEFF Research Database (Denmark)

Nørgaard, Anders; Andersen, Lars Ib; Haahr, P.E.

2008-01-01

treated aneurysm in the ascending thoracic aorta complicated with an anastomotic leak. If a short prosthesis (6 cm) had been available, the anastomotic leak would have been treated with endovascular repair. In lack of this prosthesis, we were forced to treat the patient with a method not generally...

Tratamento cirúrgico dos aneurismas toracoabdominais da aorta Surgical treatment of thoracoabdominal aortic aneurysms

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Januário M Souza

1991-04-01

Full Text Available Foram operados, em nosso Serviço, 161 aneurismas da aorta, sendo 99 por dissecção e 62 por outras causas. Em cinco pacientes, os aneurismas eram de localização toracoabdominal, sendo três por degeneração aterosclerótica e dois por dissecção; três pacientes eram do sexo feminino e a idade variou de 31 a 71 anos. Dois pacientes submeteram-se a aneurismectomia previamente (um da aorta ascendente e outro da porção proximal da aorta torácica. Revascularização miocárdica foi feita em um paciente, 40 dias antes da aneurismectomia. A indicação em todos os pacientes foi dor, causada por compressão do aneurisma, sendo que, em dois, havia insuficiência respiratória associada. Todos os pacientes foram operados através de incisão toracoabdominal e abertura do diafragma. A aorta foi substituída por tubo de Dacron, desde sua porção proximal até sua bifurcação, e as artérias viscerais foram implantadas no tubo. Quatro pacientes foram operados com pinçamento da aorta; um paciente necessitou emprego de circulação extracorpórea e parada circulatória, por impossibilidade de pinçamento da aorta junto à artéria subclávia. Todos os pacientes sobreviveram ao ato cirúrgico, ocorrendo dois óbitos no pós-operatório, um subitamente no 12º dia e outro por coma neurológico secundário a parada cardíaca causada por hipoxia.Five patients have been operated on of thoracoabdominal aortic aneurysms. The mean age was 53 years (range 31-71 and three were women. All the patients were symptomatic, three of them had arteriosclerotic aneurysms, and the other two had dissecting aneurysms. Three patients had been operated on previously. The exposure of aneurysm was made through a thoracoabdominal incision, in four patients clamps were placed above and below the aneurysm and it was incised longitudinally. Bypass between left atrium and left femoral artery with hypothermia and circulatory arrest was used in the other patients, since the

Phantoms and computational models in therapy, diagnosis and protection

International Nuclear Information System (INIS)

Anon.

1992-01-01

The development of realistic body phantoms and computational models is strongly dependent on the availability of comprehensive human anatomical data. This information is often missing, incomplete or not easily available. Therefore, emphasis is given in the Report to organ and body masses and geometries. The influence of age, sex and ethnic origins in human anatomy is considered. Suggestions are given on how suitable anatomical data can be either extracted from published information or obtained from measurements on the local population. Existing types of phantoms and computational models used with photons, electrons, protons and neutrons are reviewed in this Report. Specifications of those considered important to the maintenance and development of reliable radiation dosimetry and measurement are given. The information provided includes a description of the phantom or model, together with diagrams or photographs and physical dimensions. The tissues within body sections are identified and the tissue substitutes used or recommended are listed. The uses of the phantom or model in radiation dosimetry and measurement are outlined. The Report deals predominantly with phantom and computational models representing the human anatomy, with a short Section devoted to animal phantoms in radiobiology

Tratamento cirúrgico da coarctação de aorta pela aortoplastia trapezoidal Surgical treatment of coarctation of the aorta using trapezoidal aortoplasty

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Jarbas Jakson Dinkhuysen

2004-01-01

Full Text Available OBJETIVO: A aortoplastia trapezoidal é uma variante técnica da anastomose término-terminal que, amparada em elementos da geometria, objetiva aumentar o diâmetro da aorta ao nível da sutura reduzida e, consequentemente, a manutenção de gradientes pressóricos residuais ou recorrentes indesejáveis a curto e a longo prazo. MÉTODOS: Após a ressecção da área coarctada e tecido ductal, são confeccionados em cada coto aórtico 3 trapezóides que, ao serem confrontados, criam linha de sutura com aspecto sinusoidal (zigue-zague. Foram operados por esta técnica 33 pacientes, a maioria homens, com idades variando de 3 meses a 36 anos (m 9,5 ± 9,7. RESULTADOS: Não ocorreu mortalidade imediata ou tardia e o tempo de evolução a longo prazo foi de 1,1 a 7,6 anos (m 3,6 ± 3,4. A maioria dos pacientes ficou assintomática com níveis normais de pressão arterial, possibilitando a descontinuação da terapêutica antihipertensiva (pOBJECTIVE: Trapezoidal aortoplasty is a technical variant of end-to-end anastomosis, which, based on elements of geometry, aims at increasing the diameter of the aorta at the level of the suture, therefore reducing the occurrence of residual or recurrent pressure gradients in the short and long run. METHODS: After resecting the coarcted area and ductal tissue, 3 trapezoids are confected in each aortic stump, which, when confronted, create a suture line with a sinusoidal aspect (zigzag. Thirty-three patients underwent surgery with this technique, 22 (66.7% males, with ages ranging from 3 months to 36 years (mean of 9.84 ± 9.69. RESULTS: No immediate or late deaths occurred. Follow-up ranged from 1.1 to 7.6 years (mean of 3.6 ± 3.4. Most patients became asymptomatic with normal blood pressure levels, enabling the discontinuation of antihypertensive therapy (P<0.0001. A significant reduction in the pressure gradients was observed on Doppler echocardiography and during cardiac catheterization (P<0.001. The analysis of

Successful Percutaneous Coronary Intervention through a Severely Bent Artificial Ascending Aorta Using the DIO Thrombus Aspiration Catheter

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Akinori Fujikake

2016-01-01

Full Text Available A 66-year-old man was admitted to our institute because of chest pain. He had undergone replacement of the ascending aorta due to aortic dissection 9 years previously. We made a diagnosis of acute coronary syndrome, and coronary artery angiography was performed. Although the right coronary artery was successfully cannulated, a severe bend of the artificial aorta made it very difficult to advance the catheter into the left coronary artery. Ultimately, a DIO thrombus aspiration catheter was used to enter the left coronary artery, and a stent was implanted successfully. The DIO catheter is very useful when the selection of a guiding catheter is complicated, such as in the case of severe vessel tortuosity or a bend of the ascending aorta.

Benchmark calculations with simple phantom for neutron dosimetry (2)

International Nuclear Information System (INIS)

Yukio, Sakamoto; Shuichi, Tsuda; Tatsuhiko, Sato; Nobuaki, Yoshizawa; Hideo, Hirayama

2004-01-01

Benchmark calculations for high-energy neutron dosimetry were undertaken after SATIF-5. Energy deposition in a cylindrical phantom with 100 cm radius and 30 cm depth was calculated for the irradiation of neutrons from 100 MeV to 10 GeV. Using the ICRU four-element loft tissue phantom and four single-element (hydrogen, carbon, nitrogen and oxygen) phantoms, the depth distributions of deposition energy and those total at the central region of phantoms within l cm radius and at the whole region of phantoms within 100 cm radius were calculated. The calculated results of FLUKA, MCNPX, MARS, HETC-3STEP and NMTC/JAM codes were compared. It was found that FLUKA, MARS and NMTC/JAM showed almost the same results. For the high-energy neutron incident, the MCNP-X results showed the largest ones in the total deposition energy and the HETC-3STEP results show'ed smallest ones. (author)

Investigation of hemodynamics in the development of dissecting aneurysm within patient-specific dissecting aneurismal aortas using computational fluid dynamics (CFD) simulations.

Science.gov (United States)

Tse, Kwong Ming; Chiu, Peixuan; Lee, Heow Pueh; Ho, Pei

2011-03-15

Aortic dissecting aneurysm is one of the most catastrophic cardiovascular emergencies that carries high mortality. It was pointed out from clinical observations that the aneurysm development is likely to be related to the hemodynamics condition of the dissected aorta. In order to gain more insight on the formation and progression of dissecting aneurysm, hemodynamic parameters including flow pattern, velocity distribution, aortic wall pressure and shear stress, which are difficult to measure in vivo, are evaluated using numerical simulations. Pulsatile blood flow in patient-specific dissecting aneurismal aortas before and after the formation of lumenal aneurysm (pre-aneurysm and post-aneurysm) is investigated by computational fluid dynamics (CFD) simulations. Realistic time-dependent boundary conditions are prescribed at various arteries of the complete aorta models. This study suggests the helical development of false lumen around true lumen may be related to the helical nature of hemodynamic flow in aorta. Narrowing of the aorta is responsible for the massive recirculation in the poststenosis region in the lumenal aneurysm development. High pressure difference of 0.21 kPa between true and false lumens in the pre-aneurismal aorta infers the possible lumenal aneurysm site in the descending aorta. It is also found that relatively high time-averaged wall shear stress (in the range of 4-8 kPa) may be associated with tear initiation and propagation. CFD modeling assists in medical planning by providing blood flow patterns, wall pressure and wall shear stress. This helps to understand various phenomena in the development of dissecting aneurysm. Copyright © 2011 Elsevier Ltd. All rights reserved.

Deformable and durable phantoms with controlled density of scatterers

Energy Technology Data Exchange (ETDEWEB)

Bisaillon, Charles-Etienne; Lamouche, Guy; Dufour, Marc; Monchalin, Jean-Pierre [Industrial Materials Institute, National Research Council Canada, 75 de Mortagne, Boucherville, Quebec J4B 6Y4 (Canada); Maciejko, Romain [Optoelectronics Laboratory, Engineering Physics, Ecole Polytechnique de Montreal, PO Box 6079, Station ' Centre-ville' Montreal, Quebec H3C 3A7 (Canada)], E-mail: charles-etienne.bisaillon@cnrc-nrc.gc.ca, E-mail: guy.lamouche@cnrc-nrc.gc.ca, E-mail: marc.dufour@cnrc-nrc.gc.ca, E-mail: jean-pierre.monchalin@cnrc-nrc.gc.ca, E-mail: romain.maciejko@polytml.ca

2008-07-07

We have developed deformable and durable optical tissue phantoms with a simple and well-defined microstructure including a novel combination of scatterers and a matrix material. These were developed for speckle and elastography investigations in optical coherence tomography, but should prove useful in many other fields. We present in detail the fabrication process which involves embedding silica microspheres in a silicone matrix. We also characterize the resulting phantoms with scanning electron microscopy and optical measurements. To our knowledge, no such phantoms were proposed in the literature before. Our technique has a wide range of applicability and could also be adapted to fabricate phantoms with various optical and mechanical properties. (note)

A Novel Simple Phantom for Verifying the Dose of Radiation Therapy

Directory of Open Access Journals (Sweden)

J. H. Lee

2015-01-01

Full Text Available A standard protocol of dosimetric measurements is used by the organizations responsible for verifying that the doses delivered in radiation-therapy institutions are within authorized limits. This study evaluated a self-designed simple auditing phantom for use in verifying the dose of radiation therapy; the phantom design, dose audit system, and clinical tests are described. Thermoluminescent dosimeters (TLDs were used as postal dosimeters, and mailable phantoms were produced for use in postal audits. Correction factors are important for converting TLD readout values from phantoms into the absorbed dose in water. The phantom scatter correction factor was used to quantify the difference in the scattered dose between a solid water phantom and homemade phantoms; its value ranged from 1.084 to 1.031. The energy-dependence correction factor was used to compare the TLD readout of the unit dose irradiated by audit beam energies with 60Co in the solid water phantom; its value was 0.99 to 1.01. The setup-condition factor was used to correct for differences in dose-output calibration conditions. Clinical tests of the device calibrating the dose output revealed that the dose deviation was within 3%. Therefore, our homemade phantoms and dosimetric system can be applied for accurately verifying the doses applied in radiation-therapy institutions.

Advanced Radiation DOSimetry phantom (ARDOS): a versatile breathing phantom for 4D radiation therapy and medical imaging

Science.gov (United States)

Kostiukhina, Natalia; Georg, Dietmar; Rollet, Sofia; Kuess, Peter; Sipaj, Andrej; Andrzejewski, Piotr; Furtado, Hugo; Rausch, Ivo; Lechner, Wolfgang; Steiner, Elisabeth; Kertész, Hunor; Knäusl, Barbara

2017-10-01

A novel breathing phantom was designed for being used in conventional and ion-beam radiotherapy as well as for medical imaging. Accurate dose delivery and patient safety are aimed to be verified for four-dimensional (4D) treatment techniques compensating for breathing-induced tumor motion. The phantom includes anthropomorphic components representing an average human thorax. It consists of real tissue equivalent materials to fulfill the requirements for dosimetric experiments and imaging purposes. The different parts of the torso (lungs, chest wall, and ribs) and the tumor can move independently. Simple regular movements, as well as more advanced patient-specific breathing cycles are feasible while a reproducible setup can be guaranteed. The phantom provides the flexibility to use different types of dosimetric devices and was designed in a way that it is robust, transportable and easy to handle. Tolerance levels and the reliability of the phantom setup were determined in combination with tests on motion accuracy and reproducibility by using infrared optical tracking technology. Different imaging was performed including positron emission tomography imaging, 4D computed tomography as well as real-time in-room imaging. The initial dosimetric benchmarking studies were performed in a photon beam where dose parameters are predictable and the dosimetric procedures well established.

Advanced Radiation DOSimetry phantom (ARDOS): a versatile breathing phantom for 4D radiation therapy and medical imaging.

Science.gov (United States)

Kostiukhina, Natalia; Georg, Dietmar; Rollet, Sofia; Kuess, Peter; Sipaj, Andrej; Andrzejewski, Piotr; Furtado, Hugo; Rausch, Ivo; Lechner, Wolfgang; Steiner, Elisabeth; Kertész, Hunor; Knäusl, Barbara

2017-10-04

A novel breathing phantom was designed for being used in conventional and ion-beam radiotherapy as well as for medical imaging. Accurate dose delivery and patient safety are aimed to be verified for four-dimensional (4D) treatment techniques compensating for breathing-induced tumor motion. The phantom includes anthropomorphic components representing an average human thorax. It consists of real tissue equivalent materials to fulfill the requirements for dosimetric experiments and imaging purposes. The different parts of the torso (lungs, chest wall, and ribs) and the tumor can move independently. Simple regular movements, as well as more advanced patient-specific breathing cycles are feasible while a reproducible setup can be guaranteed. The phantom provides the flexibility to use different types of dosimetric devices and was designed in a way that it is robust, transportable and easy to handle. Tolerance levels and the reliability of the phantom setup were determined in combination with tests on motion accuracy and reproducibility by using infrared optical tracking technology. Different imaging was performed including positron emission tomography imaging, 4D computed tomography as well as real-time in-room imaging. The initial dosimetric benchmarking studies were performed in a photon beam where dose parameters are predictable and the dosimetric procedures well established.

Voxel anthropomorphic phantoms: review of models used for ionising radiation dosimetry

International Nuclear Information System (INIS)

Lemosquet, A.; Carlan, L. de; Clairand, I.

2003-01-01

Computational anthropomorphic phantoms have been used since the 1970's for dosimetric calculations. Realistic geometries are required for this operation, resulting in the development of ever more accurate phantoms. Voxel phantoms, consisting of a set of small-volume elements, appeared towards the end of the 1980's, and significantly improved on the original mathematical models. Voxel phantoms are models of the human body, obtained using computed tomography (CT) or magnetic resonance images (MRI). These phantoms are an extremely accurate representation of the human anatomy. This article provides a review of the literature available on the development of these phantoms and their applications in ionising radiation dosimetry. The bibliographical study has shown that there is a wide range of phantoms, covering various characteristics of the general population in terms of sex, age or morphology, and that they are used in applications relating to all aspects of ionising radiation. (author)

Hubungan Phantom Vibration Syndrome Terhadap Sleep Disorder dan Kondisi Stress

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Ajeng Yeni Setianingrum

2017-10-01

Full Text Available Phantom vibration syndrome is a condition where a person would feel the sensation of vibration of a cell phone as if there were incoming notification but the fact is not. This research investigated the relationship between phantom vibration syndromes, sleep disorder and stress condition. Questionnaires were distributed to 120 participants with age range 18 to 23 years old. Data of participants showed that all of participants using a smart mobile phone and 24% of them have more than one cell phone. Time usage of cell phone is at least 1 hour. 23% of participants using a cell phone for social media activity, followed by 21% related to entertainment (music, video and games. The results showed a positive relationship between phantom vibration syndrome, sleep disorder and stress condition. Insomnia contributed a greater influence on stress condition. However, the phantom vibration syndrome is more directly affecting the sleep apnea compared to insomnia and stress condition. Therefore, the phantom vibration syndrome more affects stress condition indirectly, through sleep disorder (sleep apnea and insomnia. Consequently, phantom vibration syndrome has a strong relationship with stress condition at the time of the phantom vibration syndrome can cause sleep disorder.

Estimation of computed tomography dose in various phantom shapes and compositions

Energy Technology Data Exchange (ETDEWEB)

Lee, Chang Lae [Dept. of Radiological Science, Yonsei University, Seoul (Korea, Republic of)

2017-03-15

The purpose of this study was to investigate CTDI (computed tomography dose index at center) for various phantom shapes, sizes, and compositions by using GATE (geant4 application for tomographic emission) simulations. GATE simulations were performed for various phantom shapes (cylinder, elliptical, and hexagonal prism PMMA phantoms) and phantom compositions (water, PMMA, polyethylene, polyoxymethylene) with various diameters (1-50 cm) at various kVp and mAs levels. The CTDI100center values of cylinder, elliptical, and hexagonal prism phantom at 120 kVp, 200 mAs resulted in 11.1, 13.4, and 12.2 mGy, respectively. The volume is the same, but CTDI{sub 100center} values are different depending on the type of phantom. The water, PMMA, and polyoxymethylene phantom CTDI{sub 100center} values were relatively low as the material density increased. However, in the case of Polyethylene, the CTDI{sub 100center} value was higher than that of PMMA at diameters exceeding 15 cm (CTDI{sub 100center} : 35.0 mGy). And a diameter greater than 30 cm (CTDI{sub 100center} : 17.7 mGy) showed more CTDI{sub 100center} than Water. We have used limited phantoms to evaluate CT doses. In this study, CTDI{sub 100center} values were estimated and simulated by GATE simulation according to the material and shape of the phantom. CT dosimetry can be estimated more accurately by using various materials and phantom shapes close to human body.

Screening for abdominal aortic aneurysms Rastreamento de aneurismas da aorta abdominal

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Telmo Pedro Bonamigo

2003-01-01

Full Text Available OBJECTIVE AND METHODS: Screening for abdominal aortic aneurysms may be useful to decrease mortality related to rupture. We conducted a study to assess the prevalence of abdominal aortic aneurysms in southern Brazil and to define risk factors associated with high prevalence of this disorder. The screening was conducted using abdominal ultrasound. Three groups were studied: Group 1 - cardiology clinic patients; Group 2 - individuals with severe ischemic disease and previous coronary surgery, or important lesions on cardiac catheterism; Group 3 - individuals without cardiac disease selected from the general population. All individuals were male and older than 54 years of age. The ultrasonographic diagnosis of aneurysm was based on an anteroposterior abdominal aorta diameter of 3 cm, or on an abdominal aorta diameter 0.5 cm greater than that of the supra-renal aorta. RESULTS: A total of 2.281 people were screened for abdominal aortic aneurysms in all groups: Group 1 - 768 individuals, Group 2 - 501 individuals, and Group 3 - 1012 individuals. The prevalence of aneurysms was 4.3%, 6.8% and 1.7%, respectively. Age and cigarette smoking were significantly associated with increased prevalence of aneurysms, as was the diagnosis of peripheral artery disease. DISCUSSION: We concluded that screening may be an important tool to prevent the mortality associated with abdominal aortic aneurysms surgery. Additionally, the cost of screening can be decreased if only individuals presenting significant risk factors, such as coronary and peripheral artery disease, smokers and relatives of aneurysm patients, are examined.OBJETIVO E MÉTODOS: O rastreamento de aneurisma da aorta abdominal infra-renal é importante pois pode diminuir a mortalidade relacionada à ruptura. Realizamos um estudo para definir a prevalência desses aneurismas em diversos segmentos da população em nossa região do Brasil. O rastreamento foi realizado utilizando-se a ecografia de abdômen. Tr

A solid tissue phantom for photon migration studies

International Nuclear Information System (INIS)

Cubeddu, Rinaldo; Pifferi, Antonio; Taroni, Paola; Torricelli, Alessandro; Valentini, Gianluca

1997-01-01

A solid tissue phantom made of agar, Intralipid and black ink is described and characterized. The preparation procedure is fast and easily implemented with standard laboratory equipment. An instrumentation for time-resolved transmittance measurements was used to determine the optical properties of the phantom. The absorption and the reduced scattering coefficients are linear with the ink and Intralipid concentrations, respectively. A systematic decrease of the reduced scattering coefficient dependent on the agar content is observed, but can easily be managed. The phantom is highly homogeneous and shows good repeatability among different preparations. Moreover, agar inclusions can be easily embedded in either solid or liquid matrixes, and no artefacts are caused by the solid - solid or solid - liquid interfaces. This allows one to produce reliable and realistic inhomogeneous phantoms with known optical properties, particularly interesting for studies on optical imaging through turbid media. (author)

Phantom inflation and the 'Big Trip'

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Diaz, Pedro F. [Colina de los Chopos, Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain)]. E-mail: p.gonzalezdiaz@imaff.cfmac.csic.es; Jimenez-Madrid, Jose A. [Colina de los Chopos, Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain)

2004-08-19

Primordial inflation is regarded to be driven by a phantom field which is here implemented as a scalar field satisfying an equation of state p={omega}{rho}, with {omega}-1. Being even aggravated by the weird properties of phantom energy, this will pose a serious problem with the exit from the inflationary phase. We argue, however, in favor of the speculation that a smooth exit from the phantom inflationary phase can still be tentatively recovered by considering a multiverse scenario where the primordial phantom universe would travel in time toward a future universe filled with usual radiation, before reaching the big rip. We call this transition the 'Big Trip' and assume it to take place with the help of some form of anthropic principle which chooses our current universe as being the final destination of the time transition.

Fabrication of subcutaneous veins phantom for vessel visualization system

Science.gov (United States)

Cheng, Kai; Narita, Kazuyuki; Morita, Yusuke; Nakamachi, Eiji; Honda, Norihiro; Awazu, Kunio

2013-09-01

The technique of subcutaneous veins imaging by using NIR (Near Infrared Radiation) is widely used in medical applications, such as the intravenous injection and the blood sampling. In the previous study, an automatic 3D blood vessel search and automatic blood sampling system was newly developed. In order to validate this NIR imaging system, we adopted the subcutaneous vein in the human arm and its artificial phantom, which imitate the human fat and blood vessel. The human skin and subcutaneous vein is characterized as the uncertainty object, which has the individual specificity, non-accurate depth information, non-steady state and hardly to be fixed in the examination apparatus. On the other hand, the conventional phantom was quite distinct from the human's characteristics, such as the non-multilayer structure, disagreement of optical property. In this study, we develop a multilayer phantom, which is quite similar with human skin, for improvement of NIR detection system evaluation. The phantom consists of three layers, such as the epidermis layer, the dermis layer and the subcutaneous fat layer. In subcutaneous fat layer, we built a blood vessel. We use the intralipid to imitate the optical scattering characteristics of human skin, and the hemoglobin and melanin for the optical absorption characteristics. In this study, we did two subjects. First, we decide the fabrication process of the phantom. Second, we compared newly developed phantoms with human skin by using our NIR detecting system, and confirm the availability of these phantoms.

Development of thyroid anthropomorphic phantoms for use in nuclear medicine

Science.gov (United States)

Cerqueira, R. A. D.; Maia, A. F.

2014-02-01

The objective of this study was to develop thyroid anthropomorphic phantoms to be used in control tests of medical images in scintillation cameras. The main difference among the phantoms was the neck shape: in the first, called OSCT, it was geometrically shaped, while in the second, called OSAP, it was anthropomorphically shaped. In both phantoms, thyroid gland prototypes, which were made of acrylic and anthropomorphically shaped, were constructed to allow the simulation of a healthy thyroid and of thyroids with hyperthyroidism and hypothyroidism. Images of these thyroid anthropomorphic phantoms were obtained using iodine 131 with an activity of 8.695 MBq. The iodine 131 was chosen because it is widely used in studies of thyroid scintigraphy. The images obtained proved the effectiveness of the phantoms to simulate normal or abnormal thyroids function. These phantoms can be used in medical imaging quality control programs and, also in the training of professionals involved in the analysis of images in nuclear medicine centers.

Evaluation of TGF beta1 expression and comparison the thickness of different aorta layers in experimental diabetes.

Science.gov (United States)

Cuce, G; Kalkan, S S; Esen, H H

2011-01-01

It was aimed to investigate the effects of experimental diabetes on TGF beta1 expression and tunica intima and media thickness in abdominal and thoracic aorta. Fourteen three months old female rats were divided into two groups, non-diabetic and streptozotocin (STZ) induced diabetic group. Hematoxylin-Eosin and Verhoeff's Van Gieson elastic staining and TGF beta1 immunohistochemistry staining were performed. Abdominal and thoracic intima and media thickness of aortas were measured with the oculometer. Evaluation of intima and media thickness measurements showed no significant statistical differences between non-diabetic and diabetic groups. TGF beta1 expression increased significantly in thoracic diabetic (TD) group. The 60 day duration of diabetes is not sufficiently enough time for the development of pathological changes that could lead to thickening in aortic intima-media layers. TGF beta1 expression was negative in the abdominal aorta that can predispose to the development of atherosclerosis, which could develop overtime. This finding may be interpreted as an appropriate basis for the development of atherosclerosis. In the thoracic aorta TGF beta1 may coordinate cellular events such as tissue repair (Fig. 5, Ref. 23).

Design of a head phantom produced on a 3D rapid prototyping printer and comparison with a RANDO and 3M lucite head phantom in eye dosimetry applications.

Science.gov (United States)

Homolka, Peter; Figl, Michael; Wartak, Andreas; Glanzer, Mathias; Dünkelmeyer, Martina; Hojreh, Azadeh; Hummel, Johann

2017-04-21

An anthropomorphic head phantom including eye inserts allowing placement of TLDs 3 mm below the cornea has been produced on a 3D printer using a photo-cured acrylic resin to best allow tissue equivalence. Thus H p (3) can be determined in radiological and interventional photon radiation fields. Eye doses and doses to the forehead have been compared to an Alderson RANDO head and a 3M Lucite skull phantom in terms of surface dose per incident air kerma for frontal irradiation since the commercial phantoms do not allow placement of TLDs 3 mm below the corneal surface. A comparison of dose reduction factors (DRFs) of a common lead glasses model has also been performed. Eye dose per incident air kerma were comparable between all three phantoms (printed phantom: 1.40, standard error (SE) 0.04; RANDO: 1.36, SE 0.03; 3M: 1.37, SE 0.03). Doses to the forehead were identical to eye surface doses for the printed phantom and the RANDO head (ratio 1.00 SE 0.04, and 0.99 SE 0.03, respectively). In the 3M Lucite skull phantom dose on the forehead was 15% lower than dose to the eyes attributable to phantom properties. DRF of a sport frame style leaded glasses model with 0.75 mm lead equivalence measured were 6.8 SE 0.5, 9.3 SE 0.4 and 10.5 SE 0.5 for the RANDO head, the printed phantom, and the 3M Lucite head phantom, respectively, for frontal irradiation. A comparison of doses measured in 3 mm depth and on the surface of the eyes in the printed phantom revealed no difference larger than standard errors from TLD dosimetry. 3D printing offers an interesting opportunity for phantom design with increasing potential as printers allowing combinations of tissue substitutes will become available. Variations between phantoms may provide a useful indication of uncertainty budgets when using phantom measurements to estimate individual personnel doses.

A case of Behcet's disease with aneurysms of common carotid arteries and abdominal aorta

International Nuclear Information System (INIS)

Choo, Yeon Myung; Chang, Kee Hyun; Choi, Sung Jae

1984-01-01

One case of Behcet's disease with multiple aneurysms in both common carotid arteries and abdominal aorta is presented with brief review of the literatures. A 26-year-old woman had slowly enlarging pulsatile masses in both sides of neck and recurrent ulcerations in oral cavity and genitalia. One day prior to admission, aphasia, right facial nerve palsy and right hemiplegia suddenly developed. Brain CT showed acute infarction in left basal ganglia. Both Carotid Angiography and abdominal Aortography demonstrated multiple aneurysms in both common carotid arteries and abdominal aorta with organizing thrombi and thromboembolism of internal carotid artery

[Pathophysiology, prophylaxis and treatment of reperfusion syndrome in the surgery of abdominal aorta aneurysm].

Science.gov (United States)

Sukharev, I I; Guch, A A; Medvedskyĭ, E B; Kostylev, M V; Kornitskaia, A I; Gindich, L A; Dominiak, A B; Vlaĭkov, G G

1999-01-01

The peroxidal oxidation of the lipids state was studied up, as well as of the whole blood neutrophils functional activity, hemodynamics and microcirculation of lower extremities in surgical treatment of the abdominal aorta aneurysm. The main significance in the reperfusional syndrome pathophysiology, caused by temporary overcompression of aorta, has the neutrophils activation, their interrelationship with the endothelium cells and the activity lowering of the tissue antioxidant system, manifestated by vascular spasm, which is mostly expressed in the patients with stenotic affection of the lower extremities arteries. Positive effect was noted in application of preparation corvitin, which has antioxidant action.

Simplified spinal cord phantom for evaluation of SQUID magnetospinography

International Nuclear Information System (INIS)

Adachi, Y; Oyama, D; Uehara, G; Somchai, N; Kawabata, S

2014-01-01

Spinal cord functional imaging by magnetospinography (MSG) is a noninvasive diagnostic method for spinal cord diseases. However, the accuracy and spatial resolution of lesion localization by MSG have barely been evaluated in detail so far. We developed a simplified spinal cord phantom for MSG evaluation. The spinal cord phantom is composed of a cylindrical vessel filled with saline water, which acts as a model of a neck. A set of modeled vertebrae is arranged in the cylindrical vessel, which has a neural current model made from catheter electrodes. The neural current model emulates the current distribution around the activated site along the axon of the spinal cord nerve. Our MSG system was used to observe the magnetic field from the phantom; a quadrupole-like pattern of the magnetic field distribution, which is a typical distribution pattern for spinal cord magnetic fields, was successfully reproduced by the phantom. Hence, the developed spinal cord phantom can be used to evaluate MSG source analysis methods.

OSL Based Anthropomorphic Phantom and Real-Time Organ Dosimetry

Energy Technology Data Exchange (ETDEWEB)

David E. Hintenlang, Ph.D

2009-02-10

The overall objective of this project was the development of a dosimetry system that provides the direct measurement of organ does in real-time with a sensitivity that makes it an effective tool for applications in a wide variety of health physics applications. The system included the development of a real-time readout system for fiber optic coupled (FOC) dosimeters that is integrated with a state-of-art anthropomorphic phantom to provide instantaneous measures of organ doses throughout the phantom. The small size of the FOC detectors and optical fibers allow the sensitive volume of the detector to be located at organ centroids (or multiple locations distributed through the organ) within a tissue equivalent, anthropomorphic phantom without perturbing the tissue equivalent features of the phantom. The developed phantom/dosimetry system can be used in any environment where personnel may be exposed to gamma or x-ray radiations to provide the most accurate determinations of organ and effective doses possible to date.

OSL Based Anthropomorphic Phantom and Real-Time Organ Dosimetry

International Nuclear Information System (INIS)

Hintenlang, David E.

2009-01-01

The overall objective of this project was the development of a dosimetry system that provides the direct measurement of organ doses in real-time with a sensitivity that makes it an effective tool for applications in a wide variety of health physics applications. The system included the development of a real-time readout system for fiber optic coupled (FOC) dosimeters that is integrated with a state-of-art anthropomorphic phantom to provide instantaneous measures of organ doses throughout the phantom. The small size of the FOC detectors and optical fibers allow the sensitive volume of the detector to be located at organ centroids (or multiple locations distributed through the organ) within a tissue equivalent, anthropomorphic phantom without perturbing the tissue equivalent features of the phantom. The developed phantom/dosimetry system can be used in any environment where personnel may be exposed to gamma or x-ray radiations to provide the most accurate determinations of organ and effective doses possible to date

Origem anômala de uma artéria pulmonar da aorta ascendente: resolução da hipertensão arterial pulmonar com a correção cirúrgica Anomalous origin of one pulmonary artery from the ascending aorta: surgical repair resolving pulmonary arterial hypertension

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Marco Aurélio Santos

2004-12-01

Full Text Available OBJETIVO: Enfatizar a possibilidade diagnóstica da origem anômala de uma artéria pulmonar da aorta ascendente, em lactentes com quadro de insuficiência cardíaca clinicamente intratável e sem defeito estrutural intracardíaco. MÉTODOS: Estudo retrospectivo em quatro lactentes com insuficiência cardíaca intratável, submetidos a estudo ecocardiográfico bidimensional com cortes subcostal, supraesternal e paraesternal, e a estudo hemodinâmico e angiocardiográfico na projeção ântero-posterior. RESULTADOS: Três dos quatro lactentes tinham a artéria pulmonar direita originando-se da aorta ascendente, como diagnóstico principal. No quarto paciente a artéria pulmonar esquerda originava-se da aorta ascendente associada à ampla comunicação interventricular. Os lactentes tinham pressão em ambas artérias pulmonares em nível sistêmico. Todos foram submetidos a tratamento cirúrgico que consistiu na translocação da artéria pulmonar anômala da aorta. Não houve óbitos cardíacos imediatos ou tardios. CONCLUSÃO: Uma vez estabelecido o diagnóstico de origem anômala de artéria pulmonar da aorta ascendente, na forma isolada, a correção cirúrgica deverá ser prontamente realizada, não só pelo desenvolvimento de doença vascular pulmonar, como pelos excelentes resultados cirúrgicos atualmente obtidos.OBJECTIVE: To emphasize the diagnostic possibility of the anomalous origin of one pulmonary artery from the ascending aorta in infants with clinically refractory heart failure and no intracardiac structural defect. METHODS: Retrospective study of 4 infants with refractory heart failure undergoing 2-dimensional echocardiographic study with subcostal, suprasternal, and parasternal views, and hemodynamic and angiocardiographic study in the anteroposterior projection. RESULTS: Three of the 4 infants had their right pulmonary artery originating from the ascending aorta as their major diagnosis. In the fourth patient, the left pulmonary

Introduction of a stack-phantom for PET

International Nuclear Information System (INIS)

Jonsson, C.; Schnell, P.O.; Jacobsson, H.; Engelin, L.; Danielsson, A.M.; Johansson, L.; Larsson, S.A.; Pagani, M.; Stone-Elander, S.

2002-01-01

Aim: We have previously developed a new flexible phantom system for SPECT, i.e. 'the stack phantom' (Eur. J. Nucl. Med. 27, No.2, 131-139, 2000). The unique feature of this phantom system is that it allows studies with, as well as without major degrading impacts from photon attenuation and Compton scattering. The specific aim of this work was to further develop the system with special reference to PET. Material and methods: The principle of the phantom concept is discrete sampling of 3D objects by a series of equidistant 2D planes. The 2D planes are a digitised set of 2D sections, representing the radioactivity distribution in the object of interest. Using a grey scale related to the radioactivity concentration, selected images are printed by radioactive ink on thin paper sheets and stacked into the 3D structure with low-density or with tissue equivalent material in between. Using positron emitting radionuclides, the paper sheets alone may not be sufficiently thick to avoid annihilation losses due to escaping positrons. In order to investigate the amount of additional material needed, a spot of radioactivity ( 18 F) was printed out and subsequently covered by adding thin plastic films (0.055mm) on both sides of the paper. Short PET scans (ECAT 921) were performed and the count-rate was registered after each additional layer of plastic cover. A first prototype, a cylindrical cold-spot phantom was constructed on the basis of these results. Nine identical sheets were printed out and first mounted in between 4 mm plates of polystyrene (density 1.04 g/cm 3 ). After a PET-scan, the paper sheets were re-mounted in between a low-density material (Divinycell, H30, density 0.03 g/cm 3 ) before repeating the PET scan. Results: For 18 F, the number of registered annihilation photons increased with increasing number of plastic sheets from 70% for the pure paper sheet to about 100% with 0.5 mm plastic cover on each side. PET of the low-density stacked cold spot phantom

Mammography dosimetry using an in-house developed polymethyl methacrylate phantom

International Nuclear Information System (INIS)

Sharma, R.; Sharma, S. D.; Mayya, Y. S.; Chourasiya, G.

2012-01-01

Phantom-based measurements in mammography are well-established for quality assurance (QA) and quality control (QC) procedures involving equipment performance and comparisons of X-ray machines. Polymethyl methacrylate (PMMA) is among the best suitable materials for simulation of the breast. For carrying out QA/QC exercises in India, a mammographic PMMA phantom with engraved slots for keeping thermoluminescence dosemeters (TLD) has been developed. The radiation transmission property of the developed phantom was compared with the commercially available phantoms for verifying its suitability for mammography dosimetry. The breast entrance exposure (BEE), mean glandular dose (MGD), percentage depth dose (PDD), percentage surface dose distribution (PSDD), calibration testing of automatic exposure control (AEC) and density control function of a mammography machine were measured using this phantom. MGD was derived from the measured BEE following two different methodologies and the results were compared. The PDD and PSDD measurements were carried out using LiF: Mg, Cu, P chips. The in-house phantom was found comparable with the commercially available phantoms. The difference in the MGD values derived using two different methods were found in the range of 17.5-32.6 %. Measured depth ranges in the phantom lie between 0.32 and 0.40 cm for 75 % depth dose, 0.73 and 0.92 cm for 50 % depth dose, and 1.54 and 1.78 cm for 25 % depth dose. Higher PSDD value was observed towards chest wall edge side of the phantom, which is due to the orientation of cathode-anode axis along the chest wall to the nipple direction. Results obtained for AEC configuration testing shows that the observed mean optical density (O.D) of the phantom image was 1.59 and O.D difference for every successive increase in thickness of the phantom was within ±0.15 O.D. Under density control function testing, at -2 and -1 density settings, the variation in film image O.D was within ±0.15 O.D of the normal density

Endovascular treatment of thoracic aorta aneurysm and dissection

International Nuclear Information System (INIS)

Petrov, I.; Stankov, Z.; Stefanov, St.; Stoyanov, Hr.

2015-01-01

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

Thoraco-abdominal high-pitch dual-source CT angiography: Experimental evaluation of injection protocols with an anatomical human vascular phantom

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Puippe, Gilbert D., E-mail: gilbert.puippe@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland Raemistrasse 100, CH-8091 Zurich (Switzerland); Winklehner, Anna [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland Raemistrasse 100, CH-8091 Zurich (Switzerland); Hasenclever, Peter; Plass, André [Division of Cardiac and Vascular Surgery, University Hospital Zurich, Switzerland Raemistrasse 100, CH-8091 Zurich (Switzerland); Frauenfelder, Thomas; Baumueller, Stephan [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland Raemistrasse 100, CH-8091 Zurich (Switzerland)

2012-10-15

Objective: To experimentally evaluate three different contrast injection protocols at thoraco-abdominal high-pitch dual-source computed tomography angiography (CTA), with regard to level and homogeneity of vascular enhancement at different cardiac outputs. Materials and methods: A uniphasic, a biphasic as well as an individually tailored contrast protocol were tested using a human vascular phantom. Each protocol was scanned at 5 different cardiac outputs (3–5 L/min, steps of 0.5 L/min) using an extracorporeal cardiac pump. Vascular enhancement of the thoraco-abdominal aorta was measured every 5 cm. Overall mean enhancement of each protocol and mean enhancement for each cardiac output within each protocol were calculated. Enhancement homogeneity along the z-axis was evaluated for each cardiac output and protocol. Results: Overall mean enhancement was significantly higher in the uniphasic than in the other two protocols (all p < .05), whereas the difference between the biphasic and tailored protocol was not significant (p = .76). Mean enhancement among each of the 5 cardiac outputs within each protocol was significantly different (all p < .05). Only within the tailored protocol mean enhancement differed not significantly at cardiac outputs of 3.5 L/min vs. 5 L/min (484 ± 25 HU vs. 476 ± 19 HU, p = .14) and 4 vs. 5 L/min (443 ± 49 HU vs. 476 ± 19 HU, p = .05). Both, uniphasic and tailored protocol yielded homogenous enhancement at all cardiac outputs, whereas the biphasic protocol failed to achieve homogenous enhancement. Conclusion: This phantom study suggests that diagnostic and homogenous enhancement at thoraco-abdominal high-pitch dual-source CTA is feasible with either a uniphasic or an individually tailored contrast protocol.

Development of skeletal system for mesh-type ICRP reference adult phantoms

Science.gov (United States)

Yeom, Yeon Soo; Wang, Zhao Jun; Tat Nguyen, Thang; Kim, Han Sung; Choi, Chansoo; Han, Min Cheol; Kim, Chan Hyeong; Lee, Jai Ki; Chung, Beom Sun; Zankl, Maria; Petoussi-Henss, Nina; Bolch, Wesley E.; Lee, Choonsik

2016-10-01

The reference adult computational phantoms of the international commission on radiological protection (ICRP) described in Publication 110 are voxel-type computational phantoms based on whole-body computed tomography (CT) images of adult male and female patients. The voxel resolutions of these phantoms are in the order of a few millimeters and smaller tissues such as the eye lens, the skin, and the walls of some organs cannot be properly defined in the phantoms, resulting in limitations in dose coefficient calculations for weakly penetrating radiations. In order to address the limitations of the ICRP-110 phantoms, an ICRP Task Group has been recently formulated and the voxel phantoms are now being converted to a high-quality mesh format. As a part of the conversion project, in the present study, the skeleton models, one of the most important and complex organs of the body, were constructed. The constructed skeleton models were then tested by calculating red bone marrow (RBM) and endosteum dose coefficients (DCs) for broad parallel beams of photons and electrons and comparing the calculated values with those of the original ICRP-110 phantoms. The results show that for the photon exposures, there is a generally good agreement in the DCs between the mesh-type phantoms and the original voxel-type ICRP-110 phantoms; that is, the dose discrepancies were less than 7% in all cases except for the 0.03 MeV cases, for which the maximum difference was 14%. On the other hand, for the electron exposures (⩽4 MeV), the DCs of the mesh-type phantoms deviate from those of the ICRP-110 phantoms by up to ~1600 times at 0.03 MeV, which is indeed due to the improvement of the skeletal anatomy of the developed skeleton mesh models.

Constriction of juxta-ductal aorta and rapid progression of obstruction in a newborn

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Awasthy Neeraj

2010-01-01

Full Text Available A 13-day-old baby girl presenting with features of congestive cardiac failure was found to have coarctation of the aorta (CoA and patent ductus arteriosus (PDA by echocardiography. Doppler spectral display revealed moderate CoA. Echocardiogram, 12 hours later, showed severe juxtaductal aortic coarctation with spontaneous closure of PDA. This case emphasises the need to keep a close watch on the progress of CoA in the neonatal period, even if the duct has narrowed to a small size thus demonstrating the role of constriction of juxtaductal aorta in pathogenesis of coaractation. Closure of even asmall PDA can cause acute progression CoA in the presence of posterior shelf.

Geometric Deformations of the Thoracic Aorta and Supra-Aortic Arch Branch Vessels Following Thoracic Endovascular Aortic Repair.

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Ullery, Brant W; Suh, Ga-Young; Hirotsu, Kelsey; Zhu, David; Lee, Jason T; Dake, Michael D; Fleischmann, Dominik; Cheng, Christopher P

2018-04-01

To utilize 3-D modeling techniques to better characterize geometric deformations of the supra-aortic arch branch vessels and descending thoracic aorta after thoracic endovascular aortic repair. Eighteen patients underwent endovascular repair of either type B aortic dissection (n = 10) or thoracic aortic aneurysm (n = 8). Computed tomography angiography was obtained pre- and postprocedure, and 3-D geometric models of the aorta and supra-aortic branch vessels were constructed. Branch angle of the supra-aortic branch vessels and curvature metrics of the ascending aorta, aortic arch, and stented thoracic aortic lumen were calculated both at pre- and postintervention. The left common carotid artery branch angle was lower than the left subclavian artery angles preintervention ( P Supra-aortic branch vessel angulation remains relatively static when proximal landing zones are distal to the left common carotid artery.

Arteriosclerosis in the ventral aorta and epicarditis in the bulbus arteriosus of Atlantic salmon (Salmo salar L).

Science.gov (United States)

Dalum, A S; Kristthorsdottir, K H; Griffiths, D J; Bjørklund, K; Poppe, T T

2017-06-01

Spontaneous mortality of seemingly healthy, farmed Atlantic salmon (Salmo salar L) is an increasing problem in Norwegian aquaculture. In this study, we present a morphological study of the previously undescribed syndrome of arteriosclerosis of the ventral aorta and epicarditis of the adjacent bulbus arteriosus found in farmed Atlantic salmon, with wild-captured fish as a control group. Both the ventral aorta and epicardium are vital for correct arterial compliance and vascular resistance in the respiratory capillaries of the gills. We discuss the possible implications of ventral aorta arteriosclerosis and epicarditis for blood vascular health and in particular for the increasing frequency of spontaneous gill bleeding in farmed salmon. As both these conditions primarily occur in farmed salmon, we suggest that they should be considered pathological. © 2016 John Wiley & Sons Ltd.

Porous phantoms for PET and SPECT performance evaluation and quality assurance

International Nuclear Information System (INIS)

DiFilippo, Frank P.; Price, James P.; Kelsch, Daniel N.; Muzic, Raymond F. Jr.

2004-01-01

Characterization of PET and SPECT imaging performance often requires phantoms with complex radionuclide distributions. For example, lesion detection studies use multiple spherical regions of specific target-to-background ratios to simulate cancerous lesions. Such complex distributions are typically created using phantoms with multiple fillable chambers. However, such phantoms are typically difficult and time-consuming to prepare accurately and reproducibly. A new approach using a single-chamber phantom with a porous core can overcome these difficulties. Methods: Prototypes of two designs of porous core phantoms were produced and evaluated. The 'hot spheres' phantom contained a multitude of simulated spherical lesions with diameters ranging from 6.35 to 25.4 mm ('multi-resolution' slice) and with lesion-to-background ratios ranging from 1.6 to 4.4 ('multi-contrast' slice). The 'multi-attenuation' phantom consisted of two halves. One half contained a porous core to produce regions of different attenuation but uniform activity. The other half mimicked the NEMA-94 design with cold inserts of different attenuation. Results: Both phantoms produced the expected radionuclide distributions while requiring the preparation of only a single radionuclide solution and with much reduced preparation time. In images taken on clinical PET and SPECT scanners, the porous core structures were found to contribute negligible background noise or artifact. The measured lesion-to-background ratios from the hot spheres phantom differed slightly from calculated values, with the differences attributed mainly to uncertainty in pore diameter. The measured attenuation coefficients from the multi-attenuation phantom agreed well with expected values. However, it was found that trapped air bubbles due to manufacturing defects in the porous core could potentially cause quantitative errors. Conclusion: The hot spheres and multi-attenuation porous phantoms exhibited a wide range of imaging features

Diminutive Porcelain Ascending Aorta With Supravalvular Aortic Stenosis.

Science.gov (United States)

Houmsse, Mustafa; McDavid, Asia; Kilic, Ahmet

2018-05-01

This report describes the case of a 49-year-old man with a medical history significant for congenital aortic stenosis. The patient presented with progressive shortness of breath and decreased stamina and was found to have a concentric, diminutive porcelain ascending aorta with diffuse supravalvular aortic stenosis. We describe treatment with an aortic root augmentation and Bentall procedure using hypothermic circulatory arrest. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Ruptured Sinus of Valsalva Aneurysm and Coarctation of Aorta in a Woman at Early Postpartum Period

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Erol Sener

2014-01-01

Full Text Available Coarctation of aorta and sinus of Valsalva aneurysm are frequently missed congenital cardiac defects that their diagnosis might be delayed. To our knowledge, coincidence of these cardiac defects is unusual and has not been reported in the literature before. Here, we present a patient with coarctation of aorta and ruptured noncoronary sinus of Valsalva aneurysm leading to aorto-right atrial fistula in the early postpartum period and our management of this unusual case.

Studies on Phantom Vibration and Ringing Syndrome among Postgraduate Students

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Atul Kumar Goyal

2015-03-01

Full Text Available Phantom vibrations and ringing of mobile phones are prevalent hallucinations in the general population. They might be considered as a normal brain mechanism. The aim of this study was to establish the prevalence of Phantom vibrations and ringing syndrome among students and to assess factors associated it. The survey of 300 postgraduate students belonging to different field of specialization was conducted at Kurukshetra University. 74% of students were found to have both Phantom vibrations and ringing syndrome. Whereas 17% of students felt Phantom vibration exclusively and 4% students face only Phantom ringing syndrome. Both the syndrome occurs more fervent in students who kept their mobile phone in shirt or jean pocket than to who kept mobile in handbag. 75% of students felt vibration or ringing even when the phone is switched off or phone was not in their pocket. Also the frequency of both the syndrome is directly proportional to the duration of mobile phone use and person emotional behavior. Although most of students agree that the Phantom syndrome did not bother them but some students deals with anxiety when they feel symptoms associated with Phantom syndrome. By using mobile phones in proper way, one can avoid these syndromes, or at least can ameliorate the symptoms.

Rapid prototyping of biomimetic vascular phantoms for hyperspectral reflectance imaging

Science.gov (United States)

Ghassemi, Pejhman; Wang, Jianting; Melchiorri, Anthony J.; Ramella-Roman, Jessica C.; Mathews, Scott A.; Coburn, James C.; Sorg, Brian S.; Chen, Yu; Joshua Pfefer, T.

2015-12-01

The emerging technique of rapid prototyping with three-dimensional (3-D) printers provides a simple yet revolutionary method for fabricating objects with arbitrary geometry. The use of 3-D printing for generating morphologically biomimetic tissue phantoms based on medical images represents a potentially major advance over existing phantom approaches. Toward the goal of image-defined phantoms, we converted a segmented fundus image of the human retina into a matrix format and edited it to achieve a geometry suitable for printing. Phantoms with vessel-simulating channels were then printed using a photoreactive resin providing biologically relevant turbidity, as determined by spectrophotometry. The morphology of printed vessels was validated by x-ray microcomputed tomography. Channels were filled with hemoglobin (Hb) solutions undergoing desaturation, and phantoms were imaged with a near-infrared hyperspectral reflectance imaging system. Additionally, a phantom was printed incorporating two disjoint vascular networks at different depths, each filled with Hb solutions at different saturation levels. Light propagation effects noted during these measurements-including the influence of vessel density and depth on Hb concentration and saturation estimates, and the effect of wavelength on vessel visualization depth-were evaluated. Overall, our findings indicated that 3-D-printed biomimetic phantoms hold significant potential as realistic and practical tools for elucidating light-tissue interactions and characterizing biophotonic system performance.

Iterative Otsu's method for OCT improved delineation in the aorta wall

Science.gov (United States)

Alonso, Daniel; Real, Eusebio; Val-Bernal, José F.; Revuelta, José M.; Pontón, Alejandro; Calvo Díez, Marta; Mayorga, Marta; López-Higuera, José M.; Conde, Olga M.

2015-07-01

Degradation of human ascending thoracic aorta has been visualized with Optical Coherence Tomography (OCT). OCT images of the vessel wall exhibit structural degradation in the media layer of the artery, being this disorder the final trigger of the pathology. The degeneration in the vessel wall appears as low-reflectivity areas due to different optical properties of acidic polysaccharides and mucopolysaccharides in contrast with typical ordered structure of smooth muscle cells, elastin and collagen fibers. An OCT dimension indicator of wall degradation can be generated upon the spatial quantification of the extension of degraded areas in a similar way as conventional histopathology. This proposed OCT marker can offer in the future a real-time clinical perception of the vessel status to help cardiovascular surgeons in vessel repair interventions. However, the delineation of degraded areas on the B-scan image from OCT is sometimes difficult due to presence of speckle noise, variable signal to noise ratio (SNR) conditions on the measurement process, etc. Degraded areas can be delimited by basic thresholding techniques taking advantage of disorders evidences in B-scan images, but this delineation is not optimum in the aorta samples and requires complex additional processing stages. This work proposes an optimized delineation of degraded areas within the aorta wall, robust to noisy environments, based on the iterative application of Otsu's thresholding method. Results improve the delineation of wall anomalies compared with the simple application of the algorithm. Achievements could be also transferred to other clinical scenarios: carotid arteries, aorto-iliac or ilio-femoral sections, intracranial, etc.

Monte Carlo dose calculations for phantoms with hip prostheses

International Nuclear Information System (INIS)

Bazalova, M; Verhaegen, F; Coolens, C; Childs, P; Cury, F; Beaulieu, L

2008-01-01

Computed tomography (CT) images of patients with hip prostheses are severely degraded by metal streaking artefacts. The low image quality makes organ contouring more difficult and can result in large dose calculation errors when Monte Carlo (MC) techniques are used. In this work, the extent of streaking artefacts produced by three common hip prosthesis materials (Ti-alloy, stainless steel, and Co-Cr-Mo alloy) was studied. The prostheses were tested in a hypothetical prostate treatment with five 18 MV photon beams. The dose distributions for unilateral and bilateral prosthesis phantoms were calculated with the EGSnrc/DOSXYZnrc MC code. This was done in three phantom geometries: in the exact geometry, in the original CT geometry, and in an artefact-corrected geometry. The artefact-corrected geometry was created using a modified filtered back-projection correction technique. It was found that unilateral prosthesis phantoms do not show large dose calculation errors, as long as the beams miss the artefact-affected volume. This is possible to achieve in the case of unilateral prosthesis phantoms (except for the Co-Cr-Mo prosthesis which gives a 3% error) but not in the case of bilateral prosthesis phantoms. The largest dose discrepancies were obtained for the bilateral Co-Cr-Mo hip prosthesis phantom, up to 11% in some voxels within the prostate. The artefact correction algorithm worked well for all phantoms and resulted in dose calculation errors below 2%. In conclusion, a MC treatment plan should include an artefact correction algorithm when treating patients with hip prostheses

Assembling of a phantom for quality control in pediatric radiodiagnosis

International Nuclear Information System (INIS)

Oliveira, Silvana Carvalho de; Ghilardi Netto, Thomaz; Trad, Clovis Simao; Brochi, Marco Aurelio Corte; Rocha, Sergio Luis

1996-01-01

The adaptation of an homogeneous phantom equivalent to an adult patient is presented for the valuation of pediatric radiologic images. The phantom consists basically of two plastic (methyl methacrylate) slabs, each 2.5 cm tick and two aluminium slabs, 0.5 and 1.0 mm thick. The system can simulate the chest, the skull or pelvis, and the extremities. The phantom also enables the equipment calibration, in order to reach the best radiographic image. After calibration of the equipment for several kVp and m As combinations, a phantom with known details and equivalent thickness was used to produce images. These radiographs allowed the choice of the best combination to be used. The entrance surface doses are presented for several combinations used with the pelvis and chest phantoms

Neutron production in a spherical phantom aboard ISS

International Nuclear Information System (INIS)

Tasbaz, A.; Machrafi, R.

2012-01-01

As part of an ongoing research program on radiation monitoring on International Space Station (ISS) that was established to analyze the radiation exposure levels onboard the ISS using different radiation instruments and a spherical phantom to simulate human body. Monte Carlo transport code was used to simulate the interaction of high energy protons and neutrons with the spherical phantom currently onboard ISS. The phantom has been exposed to individual proton energies and to a spectrum of neutrons. The internal to external neutron flux ratio was calculated and compared to the experimental data, recently, measured on the ISS. (author)

Phantom shocks in patients with implantable cardioverter defibrillator

DEFF Research Database (Denmark)

Berg, Selina Kikkenborg; Moons, Philip; Zwisler, Ann-Dorthe

2013-01-01

of phantom shocks.METHODS AND RESULTS: The design was secondary explorative analyses of data from a randomized controlled trial. One hundred and ninety-six patients with first-time ICD implantation (79% male, mean age 58 years) were randomized (1 : 1) to either combined rehabilitation or a control group...... questions regarding the experience of phantom shocks, date, time, and place. Twelve patients (9.4%) experienced a phantom shock, 7 in the intervention group and 5 in the control group (NS). Neither age, sex, quality of life nor perceived health at baseline was significantly related to the probability...

Quantitative magnetic resonance imaging phantoms: A review and the need for a system phantom.

Science.gov (United States)

Keenan, Kathryn E; Ainslie, Maureen; Barker, Alex J; Boss, Michael A; Cecil, Kim M; Charles, Cecil; Chenevert, Thomas L; Clarke, Larry; Evelhoch, Jeffrey L; Finn, Paul; Gembris, Daniel; Gunter, Jeffrey L; Hill, Derek L G; Jack, Clifford R; Jackson, Edward F; Liu, Guoying; Russek, Stephen E; Sharma, Samir D; Steckner, Michael; Stupic, Karl F; Trzasko, Joshua D; Yuan, Chun; Zheng, Jie

2018-01-01

The MRI community is using quantitative mapping techniques to complement qualitative imaging. For quantitative imaging to reach its full potential, it is necessary to analyze measurements across systems and longitudinally. Clinical use of quantitative imaging can be facilitated through adoption and use of a standard system phantom, a calibration/standard reference object, to assess the performance of an MRI machine. The International Society of Magnetic Resonance in Medicine AdHoc Committee on Standards for Quantitative Magnetic Resonance was established in February 2007 to facilitate the expansion of MRI as a mainstream modality for multi-institutional measurements, including, among other things, multicenter trials. The goal of the Standards for Quantitative Magnetic Resonance committee was to provide a framework to ensure that quantitative measures derived from MR data are comparable over time, between subjects, between sites, and between vendors. This paper, written by members of the Standards for Quantitative Magnetic Resonance committee, reviews standardization attempts and then details the need, requirements, and implementation plan for a standard system phantom for quantitative MRI. In addition, application-specific phantoms and implementation of quantitative MRI are reviewed. Magn Reson Med 79:48-61, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Whole-body detector calibrating with a modular phantom

Energy Technology Data Exchange (ETDEWEB)

Minev, L; Boshkova, T; Uzunov, P [Sofia Univ. (Bulgaria). Fizicheski Fakultet

1996-12-31

Human body models (phantoms) of various size and weight are produced in order to calibrate gamma spectrometers for accurate activity measurement. The phantoms are built of separate modules with mass of 0.5 kg and size 20 x 14 x 2 cm. There are modules with standard Eu-152 and Am-241 radioactivity designed for homogenous radioactivity imitating and critical organs moulding, as well as `zero` -phantom modules without activity imitating a standard human body. Human organs are modelled by 11 x 9 x 0.5 cm modules with 0.16 kg mass. The phantoms have been used to obtain calibration curves and absolute efficiencies for selected energies of radionuclides expected to be found in the Kozloduy NPP staff. It is shown that the efficiency depends not only on the mass but on the geometric size of the measured object. Scanning of phantoms has been carried out and a profile of activity obtained. The profile consists of an abrupt rising of the sum of pulses (measuring time - 20 s) when the detector passes from neck to chest, a plateau when it moves over the head or the trunk and gradual decrease over the legs. Profiles of activity in organs are best obtained with a lead collimator. 4 refs., 7 figs., 2 tabs.

Whole-body detector calibrating with a modular phantom

International Nuclear Information System (INIS)

Minev, L.; Boshkova, T.; Uzunov, P.

1995-01-01

Human body models (phantoms) of various size and weight are produced in order to calibrate gamma spectrometers for accurate activity measurement. The phantoms are built of separate modules with mass of 0.5 kg and size 20 x 14 x 2 cm. There are modules with standard Eu-152 and Am-241 radioactivity designed for homogenous radioactivity imitating and critical organs moulding, as well as 'zero' -phantom modules without activity imitating a standard human body. Human organs are modelled by 11 x 9 x 0.5 cm modules with 0.16 kg mass. The phantoms have been used to obtain calibration curves and absolute efficiencies for selected energies of radionuclides expected to be found in the Kozloduy NPP staff. It is shown that the efficiency depends not only on the mass but on the geometric size of the measured object. Scanning of phantoms has been carried out and a profile of activity obtained. The profile consists of an abrupt rising of the sum of pulses (measuring time - 20 s) when the detector passes from neck to chest, a plateau when it moves over the head or the trunk and gradual decrease over the legs. Profiles of activity in organs are best obtained with a lead collimator. 4 refs., 7 figs., 2 tabs

Capturing the Perceived Phantom Limb through Virtual Reality

Directory of Open Access Journals (Sweden)

Christian Rogers

2016-01-01

Full Text Available Phantom limb is the sensation amputees may feel when the missing limb is still attached to the body and is still moving as it would if it still existed. Despite there being between 50 and 80% of amputees who report neuropathic pain, also known as phantom limb pain (PLP, there is still little understanding of why PLP occurs. There are no fully effective long-term treatments available. One of the struggles with PLP is the difficulty for amputees to describe the sensations of their phantom limbs. The sensations may be of a limb that is in a position that is impossible for a normal limb to attain. The goal of this project was to treat those with PLP by developing a system to communicate the sensations those with PLP were experiencing accurately and easily through various hand positions using a model arm with a user friendly interface. The system was developed with Maya 3D animation software, the Leap Motion input device, and the Unity game engine. The 3D modeled arm was designed to mimic the phantom sensation being able to go beyond normal joint extensions of regular arms. The purpose in doing so was to obtain a true 3D visualization of the phantom limb.

The implantation of separating aortic stent-graft into the canine thoracic aorta: an experimental study

International Nuclear Information System (INIS)

Xia Jinguo; Shi Haibin; Yang Zhengqiang; Li Chao; Liu Sheng; Zu Qingquan; Li Linsun

2011-01-01

Objective: to assess the technical feasibility of implanting separating stent-graft into the canine thoracic aorta and to study its biocompatibility. Methods: Twelve adult dogs were randomly and equally divided into three groups. The right femoral artery was cut open, through which the separating stent-graft was inserted and deployed in the canine thoracic aorta, with the proximal end of the graft being quite close to the origin of the left subclavian artery. the technical feasibility of the deployment process was assessed. Angiography was performed at 4, 8 and 12 weeks after stent-graft placement to evaluate the position and patency of the stent-graft. Then the dogs were sacrificed and the specimens were collected for pathologic study. Both gross and microscopic examinations were made to evaluate the fixation of the stent-graft with the vessel wall, the endothelialization of stent-graft surface and the pathologic changes of the vascular wall. Results: A total of ten separating stent-grafts were successfully deployed in the canine thoracic aorta, no migration or deformation occurred. One dog died of massive bleeding due to the rupture of the right femoral artery which occurred when the delivery system containing the inner bare stent was inserted through the right femoral artery. Death occurred in another dog as a result of the ascending aorta rupture caused by the migration of outer-layer stent-graft. Angiography was conducted at 4, 8 and 12 weeks after stent-graft placement. No migration, deformation, rupture or stenosis of the implanted stent-grafts were observed. The formation of intima on the inner surface of the bare stent appeared at 4 weeks, which became more and more obvious with the time passing, and at 12 weeks complete endothelialization of stent-graft surface was observed. Conclusion: Technically, it is feasible to deploy the separating aortic stent-graft into the canine thoracic aorta. Moreover, the separating aortic stent-graft carries excellent

Designing a compact MRI motion phantom

Directory of Open Access Journals (Sweden)

Schmiedel Max

2016-09-01

Full Text Available Even today, dealing with motion artifacts in magnetic resonance imaging (MRI is a challenging task. Image corruption due to spontaneous body motion complicates diagnosis. In this work, an MRI phantom for rigid motion is presented. It is used to generate motion-corrupted data, which can serve for evaluation of blind motion compensation algorithms. In contrast to commercially available MRI motion phantoms, the presented setup works on small animal MRI systems. Furthermore, retrospective gating is performed on the data, which can be used as a reference for novel motion compensation approaches. The motion of the signal source can be reconstructed using motor trigger signals and be utilized as the ground truth for motion estimation. The proposed setup results in motion corrected images. Moreover, the importance of preprocessing the MRI raw data, e.g. phase-drift correction, is demonstrated. The gained knowledge can be used to design an MRI phantom for elastic motion.

Aortic annulus and ascending aorta: Comparison of preoperative and periooperative measurement in patients with aortic stenosis

International Nuclear Information System (INIS)

Smid, Michal; Ferda, Jiri; Baxa, Jan; Cech, Jakub; Hajek, Tomas; Kreuzberg, Boris; Rokyta, Richard

2010-01-01

Background: Precise determination of the aortic annulus size constitutes an integral part of the preoperative evaluation prior to aortic valve replacement. It enables the estimation of the size of prosthesis to be implanted. Knowledge of the size of the ascending aorta is required in the preoperative analysis and monitoring of its dilation enables the precise timing of the operation. Our goal was to compare the precision of measurement of the aortic annulus and ascending aorta using magnetic resonance (MR), multidetector-row computed tomography (MDCT), transthoracic echocardiography (TTE), and transoesophageal echocardiography (TEE) in patients with degenerative aortic stenosis. Methods and results: A total of 15 patients scheduled to have aortic valve replacement were enrolled into this prospective study. TTE was performed in all patients and was supplemented with TEE, CT and MR in the majority of patients. The values obtained were compared with perioperative measurements. For the measurement of aortic annulus, MR was found to be the most precise technique, followed by MDCT, TTE, and TEE. For the measurement of ascending aorta, MR again was found to be the most precise technique, followed by MDCT, TEE, and TTE. Conclusion: In our study, magnetic resonance was found to be the most precise technique for the measurement of aortic annulus and ascending aorta in patients with severe degenerative aortic stenosis.

Usefulness of computed tomography angiography for the detection of high-risk aortas for carotid artery stenting

International Nuclear Information System (INIS)

Yamamoto, Hiromichi; Kuwayama, Naoya; Hayashi, Nakamasa; Kubo, Michiya; Endo, Shunro

2011-01-01

This study evaluated the usefulness of computed tomography (CT) angiography for the detection of high-risk aortas for carotid artery stenting (CAS). We investigated changes in the treatment method and modifications of endovascular techniques according to the information from CT angiography. CT angiography using three-dimensional and multi-planar reconstruction was performed in 43 consecutive patients with carotid artery stenoses intended to undergo CAS. Two neurosurgeons evaluated the images and estimated the risk and difficulties of CAS. CT angiography clearly depicted the entire aorta, the supra-aortic vessels, and the ilio-femoral arteries in all patients. Abnormal vascular findings were found in 17 patients. High-risk aortic lesions for CAS were detected in 5 patients, including thick aortic plaques with thrombi in 2. We changed the treatment strategy from CAS to carotid endarterectomy (CEA) in these 2 patients. CT angiograms proved very useful in evaluating the approach routes of CAS in 12 patients. One patient had dissecting aneurysm of the thoracic aorta and another had aberrant right vertebral artery. In these two, the treatment strategy was changed from CAS to CEA. The treatment method was changed in 4 patients in total. CT angiography is useful for the detection of high-risk aortas for CAS and for the evaluation of safe approaches to the carotid artery. (author)

Solid tissue simulating phantoms having absorption at 970 nm for diffuse optics

Science.gov (United States)

Kennedy, Gordon T.; Lentsch, Griffin R.; Trieu, Brandon; Ponticorvo, Adrien; Saager, Rolf B.; Durkin, Anthony J.

2017-07-01

Tissue simulating phantoms can provide a valuable platform for quantitative evaluation of the performance of diffuse optical devices. While solid phantoms have been developed for applications related to characterizing exogenous fluorescence and intrinsic chromophores such as hemoglobin and melanin, we report the development of a poly(dimethylsiloxane) (PDMS) tissue phantom that mimics the spectral characteristics of tissue water. We have developed these phantoms to mimic different water fractions in tissue, with the purpose of testing new devices within the context of clinical applications such as burn wound triage. Compared to liquid phantoms, cured PDMS phantoms are easier to transport and use and have a longer usable life than gelatin-based phantoms. As silicone is hydrophobic, 9606 dye was used to mimic the optical absorption feature of water in the vicinity of 970 nm. Scattering properties are determined by adding titanium dioxide, which yields a wavelength-dependent scattering coefficient similar to that observed in tissue in the near-infrared. Phantom properties were characterized and validated using the techniques of inverse adding-doubling and spatial frequency domain imaging. Results presented here demonstrate that we can fabricate solid phantoms that can be used to simulate different water fractions.

Natural history of severe atheromatous disease of the thoracic aorta: a transesophageal echocardiographic study.

Science.gov (United States)

Montgomery, D H; Ververis, J J; McGorisk, G; Frohwein, S; Martin, R P; Taylor, W R

1996-01-01

This study sought to prospectively observe the morphologic and clinical natural history of severe atherosclerotic disease of the thoracic aorta as defined by transesophageal echocardiography. Atherosclerosis of the thoracic aorta has been shown to be highly associated with risk for embolic events in transesophageal studies, but the natural history of the disease under clinical conditions has not been reported. During a 20-month period, 191 of 264 patients undergoing transesophageal echocardiography had adequate visualization of the aorta to allow atherosclerotic severity to be graded as follows: grade I = normal (44 patients); grade II = intimal thickening (52 patients); grade III = atheroma or = 5 mm (19 patients); grade V = mobile lesion (14 patients). All available patients with grades IV (8 patients) and V (10 patients) disease as well as a subgroup of 12 patients with grade III disease had follow-up transesophageal echocardiographic studies (mean [+/- SD] 11.7 +/- 0.9 months, range 6 to 22). Of 30 patients undergoing follow-up transesophageal echocardiographic studies, 20 (66%) had no change in atherosclerotic severity grade. Of the remaining 10 patients, atherosclerotic severity progressed one grade in 7 and decreased in 3 with resolved mobile lesions. Of 18 patients with grade IV or V disease of the aorta who underwent a follow-up study, 11 (61%) demonstrated formation of new mobile lesions. Of 10 patients with grade V disease on initial study who underwent follow-up study, 7 (70%) demonstrated resolution of a specific previously documented mobile lesion. However, seven patients (70%) with grade V disease also demonstrated development of a new mobile lesion. Of 33 patients with grade IV or V disease, 8 (24%) died during the study period, and 1 (3%) had a clinical embolic event. The presence of severe atherosclerotic disease of the thoracic aorta as defined by transesophageal echocardiography is associated with a high mortality rate. Although the morphologic

Usefulness of ACR MRI phantom for quality assurance of MRI instruments

International Nuclear Information System (INIS)

Lee, Jung Whee; Ahn, Kook Jin; Lee, Seung Koo; Na, Dong Gyu; Oh, Chang Hyun; Chang, Yong Min; Lim, Tae Hwan

2006-01-01

To examine whether the ACR phantom could be used in quality standards for magnetic resonance imaging (MRI) instruments in Korea. We conducted the phantom test using the ACR MRI phantom in 20 MRI instruments currently used in Korea. According to ACR criteria, we acquired the phantom images which were then assessed by the following seven tests: geometric accuracy, high spatial resolution, slice thickness accuracy, slice position accuracy, image intensity uniformity, percent signal ghosting, and low contrast object detectability. The phantom images were interpreted by three experienced radiologists according to ACR criteria. Then, we examined the failure rate of each test and evaluated the inter-observer variation in the measurements and test failure. The failure rate of each test could be broken into the following components: geometric accuracy (11-21%), high contrast spatial resolution (10-15%), slice thickness accuracy(6-22%), slice position accuracy (5-17%), image intensity uniformity (6%), percent signal ghosting (16%), and low contrast object detectability (8-10%). In this series, all the failure rates were less than 30%. In addition, no inter-observer variation was seen in the measurements and test failure. ACR MRI phantom promises to be established as the standard phantom for MRI instruments in Korea because of its objectivity in assessing the phantom images

Tracked ultrasound calibration studies with a phantom made of LEGO bricks

Science.gov (United States)

Soehl, Marie; Walsh, Ryan; Rankin, Adam; Lasso, Andras; Fichtinger, Gabor

2014-03-01

In this study, spatial calibration of tracked ultrasound was compared by using a calibration phantom made of LEGO® bricks and two 3-D printed N-wire phantoms. METHODS: The accuracy and variance of calibrations were compared under a variety of operating conditions. Twenty trials were performed using an electromagnetic tracking device with a linear probe and three trials were performed using varied probes, varied tracking devices and the three aforementioned phantoms. The accuracy and variance of spatial calibrations found through the standard deviation and error of the 3-D image reprojection were used to compare the calibrations produced from the phantoms. RESULTS: This study found no significant difference between the measured variables of the calibrations. The average standard deviation of multiple 3-D image reprojections with the highest performing printed phantom and those from the phantom made of LEGO® bricks differed by 0.05 mm and the error of the reprojections differed by 0.13 mm. CONCLUSION: Given that the phantom made of LEGO® bricks is significantly less expensive, more readily available, and more easily modified than precision-machined N-wire phantoms, it prompts to be a viable calibration tool especially for quick laboratory research and proof of concept implementations of tracked ultrasound navigation.

Efficiency factors for Phoswich based lung monitor using ICRP Voxel phantoms

International Nuclear Information System (INIS)

Manohari, M.; Mathiyarasu, R.; Rajagopal, V.; Jose, M.T.; Venkatraman, B.

2016-01-01

The actinide contamination in lungs is measured either using array of HPGe detector or Phoswich based lung monitors. This paper discusses the results obtained during numerical calibration of Phoswich based lung counting system using ICRP VOXEL phantoms. The results are also compared with measured efficiency values obtained using LLNL phantom. The efficiency factors of 241 Am present in the lungs for phoswich detector was simulated using ICRP male voxel phantom and compared with experimentally observed values using LLNL Phantom. The observed deviation is 12%. The efficiency of the same for female subjects was estimated using ICRP female voxel phantom for both supine and posterior geometries

Multiple Thromboembolic Cerebral Infarctions from the Aorta in a Patient with Churg-Strauss Syndrome.

Science.gov (United States)

Okada, Hideo

2017-02-01

Ischemic stroke is a rare complication of Churg-Strauss syndrome (CSS) and its pathogenesis has not been well clarified yet. We report a case of cerebral infarction in a patient with CSS due to embolism from a thrombus on the wall of the aorta. A 39-year-old man had multiple cerebral infarctions with symptoms of mild left hemiparesis and reduced vision. He was clinically diagnosed to have CSS based on remarkable eosinophilia, history of asthma, sinusitis, pulmonary infiltrates, and histologically proven extravascular eosinophilic infiltrates in the specimen of gastric mucosa. Cerebral angiography did not show any stenotic lesions in cerebral arteries. A thrombus was detected on the wall of the aorta by transesophageal echocardiography, which was considered as the source of embolism. The thrombus resolved on follow-up examination 3 months after the onset of the stroke. This is the first case report on cerebral infarction caused by aortogenic thromboembolism in a CSS patient. Other than cerebral vasculitis, embolism from cardiovascular system, including the wall of the aorta, is a possible cause of cerebral infarctions in a CSS patient. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Quality assessment of brain images by Hoffman phantom

International Nuclear Information System (INIS)

Karimian, A.R.; Saddad, F.; Mosalla, B.; Moradkhani, S.; Degbankhan, R.; Pouladi, M.

2002-01-01

The purpose of this investigation is using Hoffman brain phantom for quality assessment of brian images in SPECT system. There are the following standards for quality control in nuclear medicine: American Association of Physicists in Medicine, National Electrical Manufacturers Association, International Electromechanical Commission, International Atomic Energy Agency. Each of the above standards has the following important orders: Physical inspection, Acceptance and Reference Testing, Periodic Q C tests (Daily, Weekly, Monthly, Quarterly, Annually). The above tests are simple physics measures. To more meaningful ones based on performance of some tasks related to clinical application it is better to use from organs' phantoms, such as: brain, cardiac, etc. In this research we made a comparison between normal and abnormal states of Hoffman brain phantom. Methods of Hoffman brain phantom was filled with a solution of Tc- 99 m (5 mCi) and water (1300 cc). this results: The investigation of small abnormalities strongly related to the operating conditions and deviation from best tuning state of the system

Phantom breast syndrome

Directory of Open Access Journals (Sweden)

Ramesh

2009-01-01

Full Text Available Phantom breast syndrome is a type of condition in which patients have a sensation of residual breast tissue and can include both non-painful sensations as well as phantom breast pain. The incidence varies in different studies, ranging from approximately 30% to as high as 80% of patients after mastectomy. It seriously affects quality of life through the combined impact of physical disability and emotional distress. The breast cancer incidence rate in India as well as Western countries has risen in recent years while survival rates have improved; this has effectively increased the number of women for whom post-treatment quality of life is important. In this context, chronic pain following treatment for breast cancer surgery is a significantly under-recognized and under-treated problem. Various types of chronic neuropathic pain may arise following breast cancer surgery due to surgical trauma. The cause of these syndromes is damage to various nerves during surgery. There are a number of assumed factors causing or perpetuating persistent neuropathic pain after breast cancer surgery. Most well-established risk factors for developing phantom breast pain and other related neuropathic pain syndromes are severe acute postoperative pain and greater postoperative use of analgesics. Based upon current evidence, the goals of prophylactic strategies could first target optimal peri-operative pain control and minimizing damage to nerves during surgery. There is some evidence that chronic pain and sensory abnormalities do decrease over time. The main group of oral medications studied includes anti-depressants, anticonvulsants, opioids, N-methyl-D-asparate receptor antagonists, mexilitine, topical lidocaine, cannabinoids, topical capsaicin and glysine antagonists. Neuromodulation techniques such as motor cortex stimulation, spinal cord stimulation, and intrathecal drug therapies have been used to treat various neuropathic pain syndromes.

Image fusion tool: Validation by phantom measurements

International Nuclear Information System (INIS)

Zander, A.; Geworski, L.; Richter, M.; Ivancevic, V.; Munz, D.L.; Muehler, M.; Ditt, H.

2002-01-01

Aim: Validation of a new image fusion tool with regard to handling, application in a clinical environment and fusion precision under different acquisition and registration settings. Methods: The image fusion tool investigated allows fusion of imaging modalities such as PET, CT, MRI. In order to investigate fusion precision, PET and MRI measurements were performed using a cylinder and a body contour-shaped phantom. The cylinder phantom (diameter and length 20 cm each) contained spheres (10 to 40 mm in diameter) which represented 'cold' or 'hot' lesions in PET measurements. The body contour-shaped phantom was equipped with a heart model containing two 'cold' lesions. Measurements were done with and without four external markers placed on the phantoms. The markers were made of plexiglass (2 cm diameter and 1 cm thickness) and contained a Ga-Ge-68 core for PET and Vitamin E for MRI measurements. Comparison of fusion results with and without markers was done visually and by computer assistance. This algorithm was applied to the different fusion parameters and phantoms. Results: Image fusion of PET and MRI data without external markers yielded a measured error of 0 resulting in a shift at the matrix border of 1.5 mm. Conclusion: The image fusion tool investigated allows a precise fusion of PET and MRI data with a translation error acceptable for clinical use. The error is further minimized by using external markers, especially in the case of missing anatomical orientation. Using PET the registration error depends almost only on the low resolution of the data

Phantom positioning variation in the Gamma Knife® Perfexion dosimetry

Energy Technology Data Exchange (ETDEWEB)

Costa, Nathalia Almeida; Potiens, Maria da Penha Albuquerque [Instituto de Pesquisas Energeticas e Nucleres (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Saraiva, Crystian [Hospital do Coracao, Sao Paulo, SP (Brazil)

2015-07-01

The use of small volume ionization chamber has become required for the dosimetry of equipment that use small radiation fields. A pinpoint ionization chamber is ideal for the dosimetry of a Gamma Knife® Perfexion (GKP) unit. In this work, this chamber was inserted into the phantom, and measurements were performed with the phantom in different positions, in order to verify if the change in the phantom positioning affects the dosimetry of the GKP. Three different phantom positions were performed. The variation in the result is within the range allowed for the dosimetry of a GKP equipment. (author)

Breast phantom for mammary tissue characterization by near infrared spectroscopy

International Nuclear Information System (INIS)

Miranda, D A; Cristiano, K L; Gutiérrez, J C

2013-01-01

Breast cancer is a disease associated to a high morbidity and mortality in the entire world. In the study of early detection of breast cancer the development of phantom is so important. In this research we fabricate a breast phantom using a ballistic gel with special modifications to simulate a normal and abnormal human breast. Optical properties of woman breast in the near infrared region were modelled with the phantom we developed. The developed phantom was evaluated with near infrared spectroscopy in order to study its relation with breast tissue. A good optical behaviour was achieved with the model fabricated

Evaluation of the 1Shot Phantom dedicated to the mammography system using FCR

International Nuclear Information System (INIS)

Nagashima, Chieko; Uchiyama, Nachiko; Moriyama, Noriyuki; Nagata, Mio; Kobayashi, Hiroyuki; Sankoda, Katsuhiro; Saotome, Shigeru; Tagi, Masahiro; Kusunoki, Tetsurou

2009-01-01

Currently daily quality control (QC) tests for mammography systems are generally evaluated by using visual analysis phantoms, which of course means subjective measurement. In our study, however, we evaluated a novel digital phantom, the 1Shot Phantom M plus (1Shot Phantom), together with automatic analysis software dedicated for mammography systems using Fuji computed radiography (FCR). The digital phantom enables objective evaluation by providing for actual physical measurement rather than subjective visual assessment. We measured contrast to noise ratio (CNR), image receptor homogeneity, missed tissue at chest wall side, modulation transfer function (MTF), and geometric distortion utilizing the 1Shot Phantom. We then compared the values obtained using the 1Shot Phantom with values obtained from the European guidelines and International Electrotechnical Commission (IEC) standards. In addition, we evaluated the convenience of using the digital phantom. The values utilizing the 1Shot Phantom and those from the European guidelines and IEC standards were consistent, but the QC tests for the European guidelines and IEC standards methods took about six hours while the same QC tests using the 1Shot Phantom took 10 minutes or less including exposure of the phantom image, measurement, and analysis. In conclusion, the digital phantom and dedicated software proved very useful and produced improved analysis for mammography systems using FCR in clinical daily QC testing because of their objectivity and substantial time-saving convenience. (author)

Preliminary Study on Hybrid Computational Phantom for Radiation Dosimetry Based on Subdivision Surface

International Nuclear Information System (INIS)

Jeong, Jong Hwi; Choi, Sang Hyoun; Cho, Sung Koo; Kim, Chan Hyeong

2007-01-01

The anthropomorphic computational phantoms are classified into two groups. One group is the stylized phantoms, or MIRD phantoms, which are based on mathematical representations of the anatomical structures. The shapes and positions of the organs and tissues in these phantoms can be adjusted by changing the coefficients of the equations in use. The other group is the voxel phantoms, which are based on tomographic images of a real person such as CT, MR and serially sectioned color slice images from a cadaver. Obviously, the voxel phantoms represent the anatomical structures of a human body much more realistically than the stylized phantoms. A realistic representation of anatomical structure is very important for an accurate calculation of radiation dose in the human body. Consequently, the ICRP recently has decided to use the voxel phantoms for the forthcoming update of the dose conversion coefficients. However, the voxel phantoms also have some limitations: (1) The topology and dimensions of the organs and tissues in a voxel model are extremely difficult to change, and (2) The thin organs, such as oral mucosa and skin, cannot be realistically modeled unless the voxel resolution is prohibitively high. Recently, a new approach has been implemented by several investigators. The investigators converted their voxel phantoms to hybrid computational phantoms based on NURBS (Non-Uniform Rational B-Splines) surface, which is smooth and deformable. It is claimed that these new phantoms have the flexibility of the stylized phantom along with the realistic representations of the anatomical structures. The topology and dimensions of the anatomical structures can be easily changed as necessary. Thin organs can be modeled without affecting computational speed or memory requirement. The hybrid phantoms can be also used for 4-D Monte Carlo simulations. In this preliminary study, the external shape of a voxel phantom (i.e., skin), HDRK-Man, was converted to a hybrid computational

Rapid prototyping of biomimetic vascular phantoms for hyperspectral reflectance imaging

Science.gov (United States)

Ghassemi, Pejhman; Wang, Jianting; Melchiorri, Anthony J.; Ramella-Roman, Jessica C.; Mathews, Scott A.; Coburn, James C.; Sorg, Brian S.; Chen, Yu; Joshua Pfefer, T.

2015-01-01

Abstract. The emerging technique of rapid prototyping with three-dimensional (3-D) printers provides a simple yet revolutionary method for fabricating objects with arbitrary geometry. The use of 3-D printing for generating morphologically biomimetic tissue phantoms based on medical images represents a potentially major advance over existing phantom approaches. Toward the goal of image-defined phantoms, we converted a segmented fundus image of the human retina into a matrix format and edited it to achieve a geometry suitable for printing. Phantoms with vessel-simulating channels were then printed using a photoreactive resin providing biologically relevant turbidity, as determined by spectrophotometry. The morphology of printed vessels was validated by x-ray microcomputed tomography. Channels were filled with hemoglobin (Hb) solutions undergoing desaturation, and phantoms were imaged with a near-infrared hyperspectral reflectance imaging system. Additionally, a phantom was printed incorporating two disjoint vascular networks at different depths, each filled with Hb solutions at different saturation levels. Light propagation effects noted during these measurements—including the influence of vessel density and depth on Hb concentration and saturation estimates, and the effect of wavelength on vessel visualization depth—were evaluated. Overall, our findings indicated that 3-D-printed biomimetic phantoms hold significant potential as realistic and practical tools for elucidating light–tissue interactions and characterizing biophotonic system performance. PMID:26662064

Veratridine activates a silent sodium-channel in rat isolated aorta

NARCIS (Netherlands)

WERMELSKIRCHEN, D; WILFFERT, B; NEBEL, U; LEIDIG, A; WIRTH, A; Peters, Thies

1992-01-01

To investigate the existence of silent Na+ channels, isolated rat aorta was treated with veratridine (0.1 mM) and the resulting Ca2+ uptake was determined. After 30-min incubation the total tissue uptake of Ca2+ and Ca2+ uptake increased from 2.325 +/- 0.017 to 2.614 +/- 0.080 nmol/mg wet weight

Quantification of breast density using dual-energy mammography with liquid phantom calibration

International Nuclear Information System (INIS)

Lam, Alfonso R; Ding, Huanjun; Molloi, Sabee

2014-01-01

Breast density is a widely recognized potential risk factor for breast cancer. However, accurate quantification of breast density is a challenging task in mammography. The current use of plastic breast-equivalent phantoms for calibration provides limited accuracy in dual-energy mammography due to the chemical composition of the phantom. We implemented a breast-equivalent liquid phantom for dual-energy calibration in order to improve the accuracy of breast density measurement. To design these phantoms, three liquid compounds were chosen: water, isopropyl alcohol, and glycerol. Chemical compositions of glandular and adipose tissues, obtained from NIST database, were used as reference materials. Dual-energy signal of the liquid phantom at different breast densities (0% to 100%) and thicknesses (1 to 8 cm) were simulated. Glandular and adipose tissue thicknesses were estimated from a higher order polynomial of the signals. Our results indicated that the linear attenuation coefficients of the breast-equivalent liquid phantoms match those of the target material. Comparison between measured and known breast density data shows a linear correlation with a slope close to 1 and a non-zero intercept of 7%, while plastic phantoms showed a slope of 0.6 and a non-zero intercept of 8%. Breast density results derived from the liquid calibration phantoms showed higher accuracy than those derived from the plastic phantoms for different breast thicknesses and various tube voltages. We performed experimental phantom studies using liquid phantoms and then compared the computed breast density with those obtained using a bovine tissue model. The experimental data and the known values were in good correlation with a slope close to 1 (∼1.1). In conclusion, our results indicate that liquid phantoms are a reliable alternative for calibration in dual-energy mammography and better reproduce the chemical properties of the target material. (paper)

Thoracic and abdominal aortas stiffen through unique extracellular matrix changes in intrauterine growth restricted fetal sheep.

Science.gov (United States)

Dodson, R Blair; Rozance, Paul J; Petrash, Carson C; Hunter, Kendall S; Ferguson, Virginia L

2014-02-01

Intrauterine growth restriction (IUGR) is a fetal complication of pregnancy epidemiologically linked to cardiovascular disease in the newborn later in life. However, the mechanism is poorly understood with very little research on the vascular structure and function during development in healthy and IUGR neonates. Previously, we found vascular remodeling and increased stiffness in the carotid and umbilical arteries, but here we examine the remodeling and biomechanics in the larger vessels more proximal to the heart. To study this question, thoracic and abdominal aortas were collected from a sheep model of placental insufficiency IUGR (PI-IUGR) due to exposure to elevated ambient temperatures. Aortas from control (n = 12) and PI-IUGR fetuses (n = 10) were analyzed for functional biomechanics and structural remodeling. PI-IUGR aortas had a significant increase in stiffness (P fetal vascular remodeling in PI-IUGR may set the stage for possible altered growth and development and help to explain the pathophysiology of adult cardiovascular disease in previously IUGR individuals.

Primary Self-Expandable Nitinol Stent Placement in Focal Lesions of Infrarenal Abdominal Aorta: Long Term Results

International Nuclear Information System (INIS)

Lastovickova, Jarmila; Peregrin, Jan H.

2008-01-01

Purpose. To evaluate the technical and clinical success, safety and long term results of percutaneous transluminal angioplasty/self-expandable nitinol stent placement of infrarenal abdominal aorta focal lesions. Materials and Methods. Eighteen patients underwent PTA of focal atherosclerotic occlusive disease of distal abdominal aorta. Two symptomatic occlusions and 16 stenoses in 10 male and 8 female patients (mean age 68.2 years) were treated with primary self-expandable nitinol stent placement. Results. Primary self-expandable nitinol stent placement was technically successful in all 18 procedures; clinical success was achieved in 100% of patients. No complications associated with the procedure occurred. During the 49.4 months of mean follow up (range 3-96, 4 months) all treated aortic segments remained patent. Conclusions. Endovascular treatment (primary self-expandable nitinol stent placement) of focal atherosclerotic lesions of distal abdominal aorta is a safe method with excellent primary technical and clinical success rates and favourable Long term results

Pseudo-aneurisma em tubo valvulado de pericárdio bovino corrugado após reconstrução da aorta ascendente: relato de caso False aneurysm of crimped bovine pericardial conduit after reconstruction of the ascending aorta: case report

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Noedir A. G. STOLF

1999-10-01

Full Text Available Os autores descrevem o caso de paciente que, 9 anos após a correção cirúrgica de um aneurisma de aorta ascendente com tubo valvulado de pericárdio bovino corrugado, evoluiu com a formação de um pseudo-aneurisma de aorta localizado, posteriormente, sobre a linha de sutura do tubo de pericárdio bovino. Foi realizada substituição do tubo de pericárdio bovino por tubo de Dacron valvulado (com prótese mecânica e reimplante dos óstios coronários utilizando-se a técnica de hemi-Cabrol. O tempo de seguimento pós-operatório do paciente é de 12 meses, permanecendo assintomático.The authors describe the case of a patient who had an aneurysm of the ascending aorta repaired with biologic valved crimped bovine pericardial conduit. Nine years after the surgery he presented a false aneurysm of the ascending aorta, located posteriorly on the suture line of the pericardial tube. The patient was reoperated and the pericardial tube was replaced by a valved Dacron composite graft using the hemi- Cabrol technique for the reimplantation of the coronary ostia. At 12 months follow-up the patient remains free of symptoms.

A methodology to develop computational phantoms with adjustable posture for WBC calibration

International Nuclear Information System (INIS)

Fonseca, T C Ferreira; Vanhavere, F; Bogaerts, R; Hunt, John

2014-01-01

A Whole Body Counter (WBC) is a facility to routinely assess the internal contamination of exposed workers, especially in the case of radiation release accidents. The calibration of the counting device is usually done by using anthropomorphic physical phantoms representing the human body. Due to such a challenge of constructing representative physical phantoms a virtual calibration has been introduced. The use of computational phantoms and the Monte Carlo method to simulate radiation transport have been demonstrated to be a worthy alternative. In this study we introduce a methodology developed for the creation of realistic computational voxel phantoms with adjustable posture for WBC calibration. The methodology makes use of different software packages to enable the creation and modification of computational voxel phantoms. This allows voxel phantoms to be developed on demand for the calibration of different WBC configurations. This in turn helps to study the major source of uncertainty associated with the in vivo measurement routine which is the difference between the calibration phantoms and the real persons being counted. The use of realistic computational phantoms also helps the optimization of the counting measurement. Open source codes such as MakeHuman and Blender software packages have been used for the creation and modelling of 3D humanoid characters based on polygonal mesh surfaces. Also, a home-made software was developed whose goal is to convert the binary 3D voxel grid into a MCNPX input file. This paper summarizes the development of a library of phantoms of the human body that uses two basic phantoms called MaMP and FeMP (Male and Female Mesh Phantoms) to create a set of male and female phantoms that vary both in height and in weight. Two sets of MaMP and FeMP phantoms were developed and used for efficiency calibration of two different WBC set-ups: the Doel NPP WBC laboratory and AGM laboratory of SCK-CEN in Mol, Belgium. (paper)

Technical Note: A new phantom design for routine testing of Doppler ultrasound.

Science.gov (United States)

Grice, J V; Pickens, D R; Price, R R

2016-07-01

The objective of this project is to demonstrate the principle and operation for a simple, inexpensive, and highly portable Doppler ultrasound quality assurance (QA) phantom intended for routine QA testing. A prototype phantom has been designed, fabricated, and evaluated. The phantom described here is powered by gravity alone, requires no external equipment for operation, and produces a stable fluid velocity useful for quality assurance. Many commercially available Doppler ultrasound testing systems can suffer from issues such as a lengthy setup, prohibitive cost, nonportable size, or difficulty in use. This new phantom design aims to address some of these problems and create a phantom appropriate for assessing Doppler ultrasound stability. The phantom was fabricated using a 3D printer. The basic design of the phantom is to provide gravity-powered flow of a Doppler fluid between two reservoirs. The printed components were connected with latex tubing and then seated in a tissue mimicking gel. Spectral Doppler waveforms were sampled to evaluate variations in the data, and the phantom was evaluated using high frame rate video to find an alternate measure of mean fluid velocity flowing in the phantom. The current system design maintains stable flow from one reservoir to the other for approximately 7 s. Color Doppler imaging of the phantom was found to be qualitatively consistent with laminar flow. Using pulsed spectral Doppler, the average fluid velocity from a sample volume approximately centered in the synthetic vessel was measured to be 56 cm/s with a standard deviation of 3.2 cm/s across 118 measurements. An independent measure of the average fluid velocity was measured to be 51.9 cm/s with a standard deviation of 0.7 cm/s over 4 measurements. The developed phantom provides stable fluid flow useful for frequent clinical Doppler ultrasound testing and attempts to address several obstacles facing Doppler phantom testing. Such an ultrasound phantom can make routine

A methodology to develop computational phantoms with adjustable posture for WBC calibration

Science.gov (United States)

Ferreira Fonseca, T. C.; Bogaerts, R.; Hunt, John; Vanhavere, F.

2014-11-01

A Whole Body Counter (WBC) is a facility to routinely assess the internal contamination of exposed workers, especially in the case of radiation release accidents. The calibration of the counting device is usually done by using anthropomorphic physical phantoms representing the human body. Due to such a challenge of constructing representative physical phantoms a virtual calibration has been introduced. The use of computational phantoms and the Monte Carlo method to simulate radiation transport have been demonstrated to be a worthy alternative. In this study we introduce a methodology developed for the creation of realistic computational voxel phantoms with adjustable posture for WBC calibration. The methodology makes use of different software packages to enable the creation and modification of computational voxel phantoms. This allows voxel phantoms to be developed on demand for the calibration of different WBC configurations. This in turn helps to study the major source of uncertainty associated with the in vivo measurement routine which is the difference between the calibration phantoms and the real persons being counted. The use of realistic computational phantoms also helps the optimization of the counting measurement. Open source codes such as MakeHuman and Blender software packages have been used for the creation and modelling of 3D humanoid characters based on polygonal mesh surfaces. Also, a home-made software was developed whose goal is to convert the binary 3D voxel grid into a MCNPX input file. This paper summarizes the development of a library of phantoms of the human body that uses two basic phantoms called MaMP and FeMP (Male and Female Mesh Phantoms) to create a set of male and female phantoms that vary both in height and in weight. Two sets of MaMP and FeMP phantoms were developed and used for efficiency calibration of two different WBC set-ups: the Doel NPP WBC laboratory and AGM laboratory of SCK-CEN in Mol, Belgium.

Computational high-resolution heart phantoms for medical imaging and dosimetry simulations

Energy Technology Data Exchange (ETDEWEB)

Gu Songxiang; Kyprianou, Iacovos [Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD (United States); Gupta, Rajiv, E-mail: songxiang.gu@fda.hhs.gov, E-mail: rgupta1@partners.org, E-mail: iacovos.kyprianou@fda.hhs.gov [Massachusetts General Hospital, Boston, MA (United States)

2011-09-21

Cardiovascular disease in general and coronary artery disease (CAD) in particular, are the leading cause of death worldwide. They are principally diagnosed using either invasive percutaneous transluminal coronary angiograms or non-invasive computed tomography angiograms (CTA). Minimally invasive therapies for CAD such as angioplasty and stenting are rendered under fluoroscopic guidance. Both invasive and non-invasive imaging modalities employ ionizing radiation and there is concern for deterministic and stochastic effects of radiation. Accurate simulation to optimize image quality with minimal radiation dose requires detailed, gender-specific anthropomorphic phantoms with anatomically correct heart and associated vasculature. Such phantoms are currently unavailable. This paper describes an open source heart phantom development platform based on a graphical user interface. Using this platform, we have developed seven high-resolution cardiac/coronary artery phantoms for imaging and dosimetry from seven high-quality CTA datasets. To extract a phantom from a coronary CTA, the relationship between the intensity distribution of the myocardium, the ventricles and the coronary arteries is identified via histogram analysis of the CTA images. By further refining the segmentation using anatomy-specific criteria such as vesselness, connectivity criteria required by the coronary tree and image operations such as active contours, we are able to capture excellent detail within our phantoms. For example, in one of the female heart phantoms, as many as 100 coronary artery branches could be identified. Triangular meshes are fitted to segmented high-resolution CTA data. We have also developed a visualization tool for adding stenotic lesions to the coronaries. The male and female heart phantoms generated so far have been cross-registered and entered in the mesh-based Virtual Family of phantoms with matched age/gender information. Any phantom in this family, along with user

Computational high-resolution heart phantoms for medical imaging and dosimetry simulations

International Nuclear Information System (INIS)

Gu Songxiang; Kyprianou, Iacovos; Gupta, Rajiv

2011-01-01

Cardiovascular disease in general and coronary artery disease (CAD) in particular, are the leading cause of death worldwide. They are principally diagnosed using either invasive percutaneous transluminal coronary angiograms or non-invasive computed tomography angiograms (CTA). Minimally invasive therapies for CAD such as angioplasty and stenting are rendered under fluoroscopic guidance. Both invasive and non-invasive imaging modalities employ ionizing radiation and there is concern for deterministic and stochastic effects of radiation. Accurate simulation to optimize image quality with minimal radiation dose requires detailed, gender-specific anthropomorphic phantoms with anatomically correct heart and associated vasculature. Such phantoms are currently unavailable. This paper describes an open source heart phantom development platform based on a graphical user interface. Using this platform, we have developed seven high-resolution cardiac/coronary artery phantoms for imaging and dosimetry from seven high-quality CTA datasets. To extract a phantom from a coronary CTA, the relationship between the intensity distribution of the myocardium, the ventricles and the coronary arteries is identified via histogram analysis of the CTA images. By further refining the segmentation using anatomy-specific criteria such as vesselness, connectivity criteria required by the coronary tree and image operations such as active contours, we are able to capture excellent detail within our phantoms. For example, in one of the female heart phantoms, as many as 100 coronary artery branches could be identified. Triangular meshes are fitted to segmented high-resolution CTA data. We have also developed a visualization tool for adding stenotic lesions to the coronaries. The male and female heart phantoms generated so far have been cross-registered and entered in the mesh-based Virtual Family of phantoms with matched age/gender information. Any phantom in this family, along with user

Reduction of thoracic aorta motion artifact with high-pitch 128-slice dual-source computed tomographic angiography: a historical control study.

Science.gov (United States)

Nakagawa, Junichiro; Tasaki, Osamu; Watanabe, Yoshiyuki; Azuma, Takeo; Ohnishi, Mitsuo; Ukai, Isao; Tahara, Kenichi; Ogura, Hiroshi; Kuwagata, Yasuyuki; Hamasaki, Toshimitsu; Shimazu, Takeshi

2013-01-01

Electrocardiogram-gated imaging combined with multi-detector row computed tomography (MDCT) has reduced cardiac motion artifacts, but it was not practical in the emergency setting. The purpose of this study was to evaluate the ability of a high-pitch, 128-slice dual-source CT (DSCT) scanner to reduce motion artifacts in patients admitted to the emergency room. This study comprised 100 patients suspected of having thoracic aorta lesions. We examined 47 patients with the 128-slice DSCT scanner (DSCT group), and 53 patients were examined with a 64-slice MDCT scanner (MDCT group). Six anatomic areas in the thoracic aorta were evaluated. Computed tomography images in the DSCT group were distinct, and significant differences were observed in images of all areas between the 2 groups except for the descending aorta. The high-pitch DSCT scanner can reduce motion artifacts of the thoracic aorta and enable radiological diagnosis even in patients with tachycardia and without breath hold.

[Phantoms for the collection of genital secretions in stallions].

Science.gov (United States)

Klug, E; Brinkhoff, D; Flüge, A; Scherbarth, R; Essich, G; Kienzler, M

1977-10-05

Practical experiences of the phantom method for collection of genital secretions from stallions are reported. Taking a phantom used in the Richard-Götze-Haus Tierärztliche Hochschule Hannover as a prototype two further models slightly modified have been constructed, baring a flat hollow in the right side of the caudal phantom body for manual inserting of the Artificial Vagina. These three models fulfill four important conditions for routine use: (1) sufficient sexual attractivity for the stallions; 80-85% successful collections of presecretions out of a total of 1050 using the dummy and 70% successful semen collections from more than 240 in total; (2) solid and resistant construction; (3) easy cleaning and desinfection of the surface of the phantom to get representative samples; (4) firm installation on a hygienic floor.

Vasorelaxant Effect of a Newly Synthesized Dihydropyridine Ethyl Ester (DHPEE on Rat Thoracic Aorta: Dual Mechanism of Action

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Hossein Babaei

2011-06-01

Full Text Available Introduction: DHPEE is a newly synthesized compound by merging the key structural elements in an angiotensin receptor blocker (Telmisartan with key structural elements in 1,4- dihydropyridine calcium channel blocker (Nifedipine. In this study, we examined dual calcium channel blocking and AT1 antagonist activity for DHPEE. Methods: The functional inhibitory characteristics of DHPEE were studied in vitro in rat thoracic aorta preparations precontracted by phenylephrine (1µM or KCl (80µM or Ang II in normal or calcium-free solutions. Results: Concentration–dependent significant relaxation was observed in aortic rings precontracted with phenylephrine, KCl or Ang II. The tension increment produced by increasing external calcium was also reduced by DHPEE. DHPEE caused a marked decrease in the maximal contractile response of the vasoactive agents and shifted their concentration-response curves to the right. Conclusion: DHPEE possesses dual characteristics and cause vasorelaxation by blocking the L-type calcium channels and blocking Ang II receptors (AT1 in rat aortic smooth muscle.

Phantom jam avoidance through in-car speed advice

NARCIS (Netherlands)

Suijs, L.C.W.; Wismans, Luc Johannes Josephus; Krol, L.; van Berkum, Eric C.

2015-01-01

The existence of phantom jams can be explained following the definition of Kerner & Konhäuser (1993) who state that a phantom jam occurs without the existence of a physical bottleneck and is caused by the imperfect driving style of road users under metastable traffic conditions. In order to prevent

Proximal thoracic aorta dimensions after continuous-flow left ventricular assist device implantation: Longitudinal changes and relation to aortic valve insufficiency.

Science.gov (United States)

Fine, Nowell M; Park, Soon J; Stulak, John M; Topilsky, Yan; Daly, Richard C; Joyce, Lyle D; Pereira, Naveen L; Schirger, John A; Edwards, Brooks S; Lin, Grace; Kushwaha, Sudhir S

2016-04-01

In this study we examined the impact of continuous-flow left ventricular assist device (CF-LVAD) support on proximal thoracic aorta dimensions. Aortic root and ascending aorta diameter were measured from serial echocardiograms before and after CF-LVAD implantation in patients with ≥6 months of support, and correlated with the development of >mild aortic valve insufficiency (AI). Of 162 patients included, mean age was 58 ± 11 years and 128 (79%) were male. Seventy-nine (63%) were destination therapy patients. Mean aortic root and ascending aorta diameters at baseline, 1 month, 6 months, 12 months and long-term follow-up (mean 2.0 ± 1.4 years) were 3.5 ± 0.4, 3.5 ± 0.3, 3.9 ± 0.3, 3.9 ± 0.2 and 4.0 ± 0.3, and 3.3 ± 0.2, 3.3 ± 0.3, 3.6 ± 0.2, 3.6 ± 0.3 and 3.6 ± 0.3 cm, respectively. Only change in aortic root diameter from 1-month to 6-month follow-up reached statistical significance (p = 0.03). Nine (6%) patients had accelerated proximal thoracic aorta expansion (>0.5 cm/year), occurring predominantly in the first 6 months after implantation. These patients were older and more likely to have hypertension and baseline proximal thoracic aorta dilation. Forty-five (28%) patients developed >mild AI at long-term follow-up, including 7 of 9 (78%) of those with accelerated proximal thoracic aorta expansion. All 7 had aortic valves that remained closed throughout the cardiac cycle, and this, along with duration of CF-LVAD support and increase in aortic root diameter, were significantly associated with developing >mild AI. CF-LVAD patients have small increases in proximal thoracic aorta dimensions that predominantly occur within the first 6 months after implantation and then stabilize. Increasing aortic root diameter was associated with AI development. Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Computational hybrid anthropometric paediatric phantom library for internal radiation dosimetry

Science.gov (United States)

Xie, Tianwu; Kuster, Niels; Zaidi, Habib

2017-04-01

Hybrid computational phantoms combine voxel-based and simplified equation-based modelling approaches to provide unique advantages and more realism for the construction of anthropomorphic models. In this work, a methodology and C++ code are developed to generate hybrid computational phantoms covering statistical distributions of body morphometry in the paediatric population. The paediatric phantoms of the Virtual Population Series (IT’IS Foundation, Switzerland) were modified to match target anthropometric parameters, including body mass, body length, standing height and sitting height/stature ratio, determined from reference databases of the National Centre for Health Statistics and the National Health and Nutrition Examination Survey. The phantoms were selected as representative anchor phantoms for the newborn, 1, 2, 5, 10 and 15 years-old children, and were subsequently remodelled to create 1100 female and male phantoms with 10th, 25th, 50th, 75th and 90th body morphometries. Evaluation was performed qualitatively using 3D visualization and quantitatively by analysing internal organ masses. Overall, the newly generated phantoms appear very reasonable and representative of the main characteristics of the paediatric population at various ages and for different genders, body sizes and sitting stature ratios. The mass of internal organs increases with height and body mass. The comparison of organ masses of the heart, kidney, liver, lung and spleen with published autopsy and ICRP reference data for children demonstrated that they follow the same trend when correlated with age. The constructed hybrid computational phantom library opens up the prospect of comprehensive radiation dosimetry calculations and risk assessment for the paediatric population of different age groups and diverse anthropometric parameters.

Prevalent hallucinations during medical internships: phantom vibration and ringing syndromes.

Directory of Open Access Journals (Sweden)

Yu-Hsuan Lin

Full Text Available BACKGROUND: Phantom vibration syndrome is a type of hallucination reported among mobile phone users in the general population. Another similar perception, phantom ringing syndrome, has not been previously described in the medical literature. METHODS: A prospective longitudinal study of 74 medical interns (46 males, 28 females; mean age, 24.8±1.2 years was conducted using repeated investigations of the prevalence and associated factors of phantom vibration and ringing. The accompanying symptoms of anxiety and depression were evaluated with the Beck Anxiety and Depression Inventories before the internship began, and again at the third, sixth, and twelfth internship months, and two weeks after the internship ended. RESULTS: The baseline prevalence of phantom vibration was 78.1%, which increased to 95.9% and 93.2% in the third and sixth internship months. The prevalence returned to 80.8% at the twelfth month and decreased to 50.0% 2 weeks after the internship ended. The baseline prevalence of phantom ringing was 27.4%, which increased to 84.9%, 87.7%, and 86.3% in the third, sixth, and twelfth internship months, respectively. This returned to 54.2% two weeks after the internship ended. The anxiety and depression scores also increased during the internship, and returned to baseline two weeks after the internship. There was no significant correlation between phantom vibration/ringing and symptoms of anxiety or depression. The incidence of both phantom vibration and ringing syndromes significantly increased during the internship, and subsequent recovery. CONCLUSION: This study suggests that phantom vibration and ringing might be entities that are independent of anxiety or depression during evaluation of stress-associated experiences during medical internships.

Pixelized measurement of {sup 99m}Tc-HDP micro particles formed in gamma correction phantom pinhole scan: A reference study

Energy Technology Data Exchange (ETDEWEB)

Jung, Joo Young; Yoon, Do Kyun; Chung, Yong An [Catholic University of Korea, College of Medicine, Seoul (Korea, Republic of); Cheon, Gi Jeong; Lee, Yun Sang; Ha, Seunggyun [Radiopharmaceutical Science Laboratory, Dept. of Nuclear MedicineSeoul National University, College of Medicine, Seoul (Korea, Republic of); Bahk, Yong Whee [Dept. of Nuclear Medicine, Sung Ae General Hospital, Seoul (Korea, Republic of)

2016-09-15

Currently, traumatic bone diseases are diagnosed by assessing the micro {sup 99m}Tc-hydroxymethylene diphosphonate (HDP) uptake in injured trabeculae with ongoing osteoneogenesis demonstrated by gamma correction pinhole scan (GCPS). However, the mathematic size quantification of micro-uptake is not yet available. We designed and performed this phantom-based study to set up an in-vitro model of the mathematical calculation of micro-uptake by the pixelized measurement. The micro {sup 99m}Tc-HDP deposits used in this study were spontaneously formed both in a large standard flood and small house-made dish phantoms. The processing was as follows: first, phantoms were flooded with distilled water and {sup 99m}Tc-HDP was therein injected to induce micro {sup 99m}Tc-HDP deposition; second, the deposits were scanned using parallel-hole and pinhole collimator to generally survey {sup 99m}Tc-HDP deposition pattern; and third, the scans underwent gamma correction (GC) to discern individual deposits for size measurement. In original naïve scans, tracer distribution was simply nebulous in appearance and, hence, could not be measured. Impressively, however, GCPS could discern individual micro deposits so that they were calculated by pixelized measurement. Phantoms naturally formed micro {sup 99m}Tc-HDP deposits that are analogous to {sup 99m}Tc-HDP uptake on in-vivo bone scan. The smallest one we measured was 0.414 mm. Flooded phantoms and therein injected {sup 99m}Tc-HDP form nebulous micro {sup 99m}Tc-HDP deposits that are rendered discernible by GCPB and precisely calculable using pixelized measurement. This method can be used for precise quantitative and qualitative diagnosis of bone and joint diseases at the trabecular level.

Estrutura, ultraestrutura e morfometria da aorta de paca (Cuniculus paca, Linnaeus, 1766) criada em cativeiro

OpenAIRE

Garcia Filho,S.P.; Martins,L.L.; Reis,A.C.G.; Pacheco,M.R.; Machado,M.R.F.

2012-01-01

Descreveram-se a morfologia, morfometria e ultraestrutura de segmentos das porções torácica e abdominal da aorta de quatro pacas (Cuniculus paca) adultas. Os segmentos aórticos foram analisados à microscopia de luz e à microscopia eletrônica de varredura. Mensuraram-se as espessuras do complexo formado pelas túnicas íntima e média, além da túnica adventícia. Os valores referentes à espessura do complexo formado pelas túnicas íntima e média da aorta torácica cranial foram significativamente ma...

Origem anômala da artéria pulmonar direita em aorta ascendente (hemitruncus Anomalous origin of right pulmonary artery from ascending aorta (hemitruncus

Directory of Open Access Journals (Sweden)

Ivan Romero Rivera

1998-05-01

Full Text Available A origem da artéria pulmonar direita em aorta ascendente é uma anomalia congênita rara, com poucos casos descritos na literatura. Descrevemos dois casos desta malformação, um associado à interrupção de arco aórtico tipo B. Em ambos, o diagnóstico foi realizado mediante ecocardiografia bidimensional, com confirmação angiográfica em um. A origem da artéria pulmonar direita era próxima à valva aórtica, anomalia patogeneticamente diferente da origem perto da artéria inominada.The origin of the right pulmonary artery from the ascending aorta is a rare congenital anomaly, with very few reports in the literature. We describe two cases of this rare malformation, one of them, associated with interruption of the aortic arch (type B. In both cases, the diagnosis was made by two-dimensional echocardiography, with angiographic confirmation in one of them. The origin of the right pulmonary artery was close to the aortic valve, anomaly pathogenetically distinct from the type that arises close to the innominate artery.

Fat ViP MRI: Virtual Phantom Magnetic Resonance Imaging of water-fat systems.

Science.gov (United States)

Salvati, Roberto; Hitti, Eric; Bellanger, Jean-Jacques; Saint-Jalmes, Hervé; Gambarota, Giulio

2016-06-01

Virtual Phantom Magnetic Resonance Imaging (ViP MRI) is a method to generate reference signals on MR images, using external radiofrequency (RF) signals. The aim of this study was to assess the feasibility of ViP MRI to generate complex-data images of phantoms mimicking water-fat systems. Various numerical phantoms with a given fat fraction, T2* and field map were designed. The k-space of numerical phantoms was converted into RF signals to generate virtual phantoms. MRI experiments were performed at 4.7T using a multi-gradient-echo sequence on virtual and physical phantoms. The data acquisition of virtual and physical phantoms was simultaneous. Decomposition of the water and fat signals was performed using a complex-based water-fat separation algorithm. Overall, a good agreement was observed between the fat fraction, T2* and phase map values of the virtual and numerical phantoms. In particular, fat fractions of 10.5±0.1 (vs 10% of the numerical phantom), 20.3±0.1 (vs 20%) and 30.4±0.1 (vs 30%) were obtained in virtual phantoms. The ViP MRI method allows for generating imaging phantoms that i) mimic water-fat systems and ii) can be analyzed with water-fat separation algorithms based on complex data. Copyright © 2016 Elsevier Inc. All rights reserved.

Caval filter implantation under MRI control - experimental in vitro and in vivo investigations

International Nuclear Information System (INIS)

Neuerburg, J.; Buecker, A.; Adam, G.; Leenen, M.; Guenther, R.W.; Hurtak, M.S.W.

1997-01-01

Purpose: An instrument has been developed for the introduction of caval filters which can be used with MRI; it has been investigated in in vitro and in in vivo experiments. Material and method: The ferromagnetic components of a commercially available instrument for the femoral introduction of the MR-eye TM Tulip IVC filter were changed for similar, non-ferromagnetic parts and the lock and dilator marked with dysprosium oxide rings. The instrument was used in a flow phantom and in animal experiments (two domestic pigs) in order to insert filters under MRI control on a 1.5 T Philips Gyroscan with integrated mobile digital subtraction angiography. Results: Both in vitro and in vivo, the introducer, catheter and caval filter could be identified by MRI and positioned under MRI control. The position of the filter as indicated by MRI corresponded with radiological and macroscopic findings in all cases (5 phantoms, 2 pigs). Conclusion: The early experimental results indicate that percutaneous introduction of caval filters with placement under MRI control is possible. (orig.) [de

Development of polygonal surface version of ICRP reference phantoms: Preliminary study for posture change

International Nuclear Information System (INIS)

Nguyen, Tat Thang; Yeom, Yeon Soo; Han, Min Cheol; Kim, Chan Hyeong

2013-01-01

Even though International Commission on Radiological Protection (ICRP) officially adopted a set of adult male and female voxel phantoms as the ICRP reference phantoms, there are several critical limitations due to the nature of voxel geometry and their low voxel resolutions. In order to overcome these limitations of the ICRP phantoms, we are currently developing polygonal surface version of ICRP reference phantoms by directly converting the ICRP voxel phantoms to polygonal surface geometries. Among the many advantages of the ICRP polygonal surface phantom, especially, it is flexible and deformable. In principle, it is, therefore, possible to make the posture-changed ICRP phantoms which can provide more accurate dose values for exposure situations strongly relevant to worker's postures. As a preliminary study for developing the posture-changed ICRP phantoms, in this work we changed the posture of the preliminary version of ICRP male polygon-surface phantom constructed in the previous study. Organ doses were then compared between original and posture-changed phantoms. In the present study, we successfully changed a posture of the preliminary version of ICRP male polygon-surface phantom to the walking posture. From this results, it was explicitly shown that the polygon-surface version of the ICRP phantoms can be sufficiently modified to be various postures with the posture-changing method used in this study. In addition, it was demonstrated that phantom's posture must be considered in certain exposure situations, which can differ dose values from the conventional standing-posture phantom

Increased albumin permeation in eyes, aorta, and kidney of hypertensive rats fed galactose

International Nuclear Information System (INIS)

Tilton, R.G.; LaRose, L.; Chang, K.; Weigel, C.J.; Williamson, J.R.

1986-01-01

These experiments were undertaken to determine whether ingestion of galactose increases albumin permeation in the vasculature of hypertensive rats. 50% dextrin (control) or 50% galactose diets were fed to unilaterally nephrectomized, male Sprague-Dawley rats weighing 200 g. Hypertension (systolic pressure >175 mmHg) was induced by weekly IM injections of 25 mg/kg DOCA and 1% saline drinking water; 3 months later 125 I-albumin permeation was assessed in whole eyes, aorta and kidneys. 125 I-albumin permeation was significantly increased in all 3 tissues of hypertensive rats (n = 9) vs controls (n = 9): aorta (3.30 +/- 0.19 (SD) vs 2.87 +/- 0.14), eye (3.15 +/- 0.14 vs 2.59 +/- 0.11), and kidney (6.58 +/- 0.63 vs 3.85 +/- 0.50). Albumin permeation was increased still further in hypertensive rats fed the galactose diet (n = 8): aorta (3.75 +/- 0.38), eye (3.82 +/- 0.17), and kidney (10.74 +/- 3.13). Hypertension +/- galactose feeding had no effect on albumin permeation in lung, skin, or brain. These findings indicate that: (1) hypertension increases albumin permeation in vessels affected by diabetic vascular diseases, and 2) hypertension-induced increases in albumin permeation are increased still further by galactose ingestion, presumably mediated by imbalances in polyol/insitol metabolism (analogous to those induced by diabetes) independent of hyperglycemia and/or insulinopenia

Aorta Structural Alterations in Term Neonates: The Role of Birth and Maternal Characteristics

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Marco Matteo Ciccone

2013-01-01

Full Text Available Aim. To evaluate the influence of selected maternal and neonatal characteristics on aorta walls in term, appropriately grown-for-gestational age newborns. Methods. Age, parity, previous abortions, weight, height, body mass index before and after delivery, smoking, and history of hypertension, of diabetes, of cardiovascular diseases, and of dyslipidemia were all assessed in seventy mothers. They delivered 34 males and 36 females healthy term newborns who underwent ultrasound evaluation of the anteroposterior infrarenal abdominal aorta diameter (APAO, biochemical profile (glucose, insulin, total cholesterol, HDL and LDL cholesterol, triglycerides, fibrinogen, and D-dimers homeostasis model assessment [HOMAIR]index, and biometric parameters. Results. APAO was related to newborn length (r=+0.36; P=0.001, head circumference (r=+0.37; P=0.001, gestational age (r=+0.40, P=0.0005, HOMA index (r=+0.24; P=0.04, and D-dimers (r=+0.33, P=0.004. Smoke influenced APAO values (odds ratio: 1.80; confidence interval 95%: 1.05–3.30, as well as diabetes during pregnancy (r=+0.42, P=0.0002. Maternal height influenced neonatal APAO (r=+0.47, P=0.00003. Multiple regression analysis outlined neonatal D-dimers as still significantly related to neonatal APAO values. Conclusions. Many maternal and neonatal characteristics could influence aorta structures. Neonatal D-dimers are independently related to APAO.

Pathomorphological changes of aorta in fetuses and newborns exposed to experimental maternal escherichiosis

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Vladimir Markovskyi

2018-04-01

Full Text Available Intrauterine infections occupy a leading place in the perinatal mortality structure. The aim of this study was to identify the morphological features of the aorta in progenies born from mothers with subacute prolonged infectious and inflammatory process. Two experimental studies were performed on WAG line laboratory rats. The comparison group consisted of newborns died due to acute postnatal hypoxia. The main group included fetuses and newborns born from Escherichia coli infected mothers. The differences between the vessels of two study groups were not observed in macroscopic examination. In the group of progenies born from infected mothers, the average thickness of the aorta increased in comparison with the group under hypoxia influence, due to the inner and middle membranes, which can be interpreted as the sclerotic changes development. There was tunica adventitia volume increase in the group with hypoxia, which can be explained by edema caused by increased vascular permeability. Morphological signs of endothelial dysfunction were found in both study groups, which were expressed in the endotheliocytes flattening with their subsequent desquamation more pronounced in the group with hypoxia. It is apparently related to the process severity. There is a violation of the elastic and collagen fibers ratio towards the second in the vessel wall under the hypoxia influence, which reduces the elastic properties of the aorta.

Essential Thrombocytosis-Associated Thromboembolism in the Abdominal Aorta

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Byung Kwon Chong

2016-10-01

Full Text Available Essential thrombocytosis (ET is a myeloproliferative disorder characterized by an anomalous increase in platelet production. Many patients with ET are asymptomatic. Few studies have reported ET-associated thromboembolism in large vessels such as the aorta. We report a patient with ET who presented with peripheral embolism from an abdominal aortic thrombus and developed acute limb ischemia. The patient underwent aortic replacement successfully. The patient’s platelet count was controlled with hydroxyurea, and no recurrence was noted over 2 years of follow-up.

Ischemic colitis complicating reconstruction of the abdominal aorta

DEFF Research Database (Denmark)

Schroeder, T V; Christoffersen, J K; Andersen, J

1985-01-01

A review of 23 patients with ischemic colitis after surgical treatment of the abdominal aorta disclosed a pathogenetic heterogeneous finding. Ligation of the inferior mesenteric artery, abolished collateral blood supply or nonocclusive low flow state, or both, was a common feature. An incidence o...... of 0.5 per cent was revealed for full-thickness necrosis. The mortality was 70 per cent since diagnosis was made first since perforation and peritonitis had occurred. On the basis of these findings vital prophylactic measures and diagnostic possibilities are discussed herein....

Stress Alone or associated with Ethanol Induces Prostanoid Release in Rat Aorta via α2-Adrenoceptor

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Baptista, Rafaela de Fátima Ferreira [Departamento de Farmacologia - Instituto de Biociências - Universidade Estadual Paulista - UNESP - São Paulo, SP (Brazil); Laboratório de Farmacologia - Faculdade de Medicina de Marília - FAMEMA, SP (Brazil); Taipeiro, Elane de Fátima [Laboratório de Farmacologia - Faculdade de Medicina de Marília - FAMEMA, SP (Brazil); Queiroz, Regina Helena Costa [Departamento de Análise Clínica - Toxicológica e Ciência de Alimentos - Faculdade de Ciências Farmacêuticas - USP, São Paulo, SP (Brazil); Chies, Agnaldo Bruno [Departamento de Farmacologia - Instituto de Biociências - Universidade Estadual Paulista - UNESP - São Paulo, SP (Brazil); Laboratório de Farmacologia - Faculdade de Medicina de Marília - FAMEMA, SP (Brazil); Cordellini, Sandra, E-mail: cordelli@ibb.unesp.br [Departamento de Farmacologia - Instituto de Biociências - Universidade Estadual Paulista - UNESP - São Paulo, SP (Brazil)

2014-03-15

Stress and ethanol are both, independently, important cardiovascular risk factors. To evaluate the cardiovascular risk of ethanol consumption and stress exposure, isolated and in association, in male adult rats. Rats were separated into 4 groups: Control, ethanol (20% in drinking water for 6 weeks), stress (immobilization 1h day/5 days a week for 6 weeks) and stress/ethanol. Concentration-responses curves to noradrenaline - in the absence and presence of yohimbine, L-NAME or indomethacin - or to phenylephrine were determined in thoracic aortas with and without endothelium. EC50 and maximum response (n=8-12) were compared using two-way ANOVA/Bonferroni method. Either stress or stress in association with ethanol consumption increased the noradrenaline maximum responses in intact aortas. This hyper-reactivity was eliminated by endothelium removal or by the presence of either indomethacin or yohimbine, but was not altered by the presence of L-NAME. Meanwhile, ethanol consumption did not alter the reactivity to noradrenaline. The phenylephrine responses in aortas both with and without endothelium also remained unaffected regardless of protocol. Chronic stress increased rat aortic responses to noradrenaline. This effect is dependent upon the vascular endothelium and involves the release of vasoconstrictor prostanoids via stimulation of endothelial alpha-2 adrenoceptors. Moreover, chronic ethanol consumption appeared to neither influence noradrenaline responses in rat thoracic aorta, nor did it modify the increase of such responses observed as a consequence of stress exposure.

Stress Alone or associated with Ethanol Induces Prostanoid Release in Rat Aorta via α2-Adrenoceptor

International Nuclear Information System (INIS)

Baptista, Rafaela de Fátima Ferreira; Taipeiro, Elane de Fátima; Queiroz, Regina Helena Costa; Chies, Agnaldo Bruno; Cordellini, Sandra

2014-01-01

Stress and ethanol are both, independently, important cardiovascular risk factors. To evaluate the cardiovascular risk of ethanol consumption and stress exposure, isolated and in association, in male adult rats. Rats were separated into 4 groups: Control, ethanol (20% in drinking water for 6 weeks), stress (immobilization 1h day/5 days a week for 6 weeks) and stress/ethanol. Concentration-responses curves to noradrenaline - in the absence and presence of yohimbine, L-NAME or indomethacin - or to phenylephrine were determined in thoracic aortas with and without endothelium. EC50 and maximum response (n=8-12) were compared using two-way ANOVA/Bonferroni method. Either stress or stress in association with ethanol consumption increased the noradrenaline maximum responses in intact aortas. This hyper-reactivity was eliminated by endothelium removal or by the presence of either indomethacin or yohimbine, but was not altered by the presence of L-NAME. Meanwhile, ethanol consumption did not alter the reactivity to noradrenaline. The phenylephrine responses in aortas both with and without endothelium also remained unaffected regardless of protocol. Chronic stress increased rat aortic responses to noradrenaline. This effect is dependent upon the vascular endothelium and involves the release of vasoconstrictor prostanoids via stimulation of endothelial alpha-2 adrenoceptors. Moreover, chronic ethanol consumption appeared to neither influence noradrenaline responses in rat thoracic aorta, nor did it modify the increase of such responses observed as a consequence of stress exposure

Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

International Nuclear Information System (INIS)

Xu, X. Geroge

2011-01-01

A radiation bioassay program relies on a set of standard human phantoms to calibrate and assess radioactivity levels inside a human body for radiation protection and nuclear medicine imaging purposes. However, the methodologies in the development and application of anthropomorphic phantoms, both physical and computational, had mostly remained the same for the past 40 years. We herein propose a 3-year research project to develop medical image-based physical and computational phantoms specifically for radiation bioassay applications involving internally deposited radionuclides. The broad, long-term objective of this research was to set the foundation for a systematic paradigm shift away from the anatomically crude phantoms in existence today to realistic and ultimately individual-specific bioassay methodologies. This long-term objective is expected to impact all areas of radiation bioassay involving nuclear power plants, U.S. DOE laboratories, and nuclear medicine clinics.

Polyvinyl chloride plastisol breast phantoms for ultrasound imaging.

Science.gov (United States)

de Carvalho, Isabela Miller; De Matheo, Lucas Lobianco; Costa Júnior, José Francisco Silva; Borba, Cecília de Melo; von Krüger, Marco Antonio; Infantosi, Antonio Fernando Catelli; Pereira, Wagner Coelho de Albuquerque

2016-08-01

Ultrasonic phantoms are objects that mimic some features of biological tissues, allowing the study of their interactions with ultrasound (US). In the diagnostic-imaging field, breast phantoms are an important tool for testing performance and optimizing US systems, as well as for training medical professionals. This paper describes the design and manufacture of breast lesions by using polyvinyl chloride plastisol (PVCP) as the base material. Among the materials available for this study, PVCP was shown to be stable, durable, and easy to handle. Furthermore, it is a nontoxic, nonpolluting, and low-cost material. The breast's glandular tissue (image background) was simulated by adding graphite powder with a concentration of 1% to the base material. Mixing PVCP and graphite powder in differing concentrations allows one to simulate lesions with different echogenicity patterns (anechoic, hypoechoic, and hyperechoic). From this mixture, phantom materials were obtained with speed of sound varying from 1379.3 to 1397.9ms(-1) and an attenuation coefficient having values between 0.29 and 0.94dBcm(-1) for a frequency of 1MHz at 24°C. A single layer of carnauba wax was added to the lesion surface in order to evaluate its applicability for imaging. The images of the phantoms were acquired using commercial ultrasound equipment; a specialist rated the images, elaborating diagnoses representative of both benign and malignant lesions. The results indicated that it was possible to easily create a phantom by using low-cost materials, readily available in the market and stable at room temperature, as the basis of ultrasonic phantoms that reproduce the image characteristics of fatty breast tissue and typical lesions of the breast. Copyright © 2016 Elsevier B.V. All rights reserved.

AdS Black Hole with Phantom Scalar Field

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Limei Zhang

2017-01-01

Full Text Available We present an AdS black hole solution with Ricci flat horizon in Einstein-phantom scalar theory. The phantom scalar fields just depend on the transverse coordinates x and y, which are parameterized by the parameter α. We study the thermodynamics of the AdS phantom black hole. Although its horizon is a Ricci flat Euclidean space, we find that the thermodynamical properties of the black hole solution are qualitatively the same as those of AdS Schwarzschild black hole. Namely, there exists a minimal temperature and the large black hole is thermodynamically stable, while the smaller one is unstable, so there is a so-called Hawking-Page phase transition between the large black hole and the thermal gas solution in the AdS space-time in Poincare coordinates. We also calculate the entanglement entropy for a strip geometry dual to the AdS phantom black holes and find that the behavior of the entanglement entropy is qualitatively the same as that of the black hole thermodynamical entropy.

Computer phantoms for simulating ultrasound B-mode and CFM images

DEFF Research Database (Denmark)

Jensen, Jørgen Arendt; Munk, Peter

1997-01-01

in a file that defines their position and amplitude. Adjusting the number of scatterers and their relative amplitude yields the proper image.Five different computer phantoms are described. The first one consists of a number of point targets. It is used for studying the point spread function as a function...... of spatial position, and can give an indication of sidelobe levels and focusing abilities. The second phantom contains a number of cysts and point tagets along with a homogeneous speckle pattern. This is used for investigating image contrast, and the system's ability to detect low-contrast objects. The third...... phantom is for realistic clinical imaging. It contains the image of a 12 week old fetus, where the placenta and the upper body of the fetus is visible. This phantom gives an indication of the whole system's capability for real imaging. The current fetus phantom is only two-dimensional, as it is constant...

Construction of cardiac anthropomorphic phantom for simulation of radiological exams

International Nuclear Information System (INIS)

Bandeira, C.K.; Vieira Neto, H.; Vieira, M.P.M.M.

2017-01-01

Phantoms are simulating objects of structures of the human body and can be applied in the quality control and calibration of radiological equipment. The aim of the work is the development of a cardiac anthropomorphic phantom to assist in the elaboration of protocols of dynamic studies that demonstrate the blood circulation inside the cardiac chambers. For the construction of the phantom was used latex, applied in layers on an anatomical model of heart, having been constructed the cardiac chambers and atrioventricular valves. Cardiac chambers were connected to the cannulas for fluid injection and simulation of the circulatory system. The constructed phantom presents anthropomorphic characteristics and allows the circulation of the fluid without reflux, but the thickness of the catheters used does not yet allow flows of greater order of magnitude. This phantom has the potential to be used in the dynamic simulation of cardiac exams, contributing to the elaboration and adequacy of computed tomography protocols

Design and fabrication of a realistic anthropomorphic heterogeneous head phantom for MR purposes.

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Sossena Wood

Full Text Available The purpose of this study is to design an anthropomorphic heterogeneous head phantom that can be used for MRI and other electromagnetic applications.An eight compartment, physical anthropomorphic head phantom was developed from a 3T MRI dataset of a healthy male. The designed phantom was successfully built and preliminarily evaluated through an application that involves electromagnetic-tissue interactions: MRI (due to it being an available resource. The developed phantom was filled with media possessing electromagnetic constitutive parameters that correspond to biological tissues at ~297 MHz. A preliminary comparison between an in-vivo human volunteer (based on whom the anthropomorphic head phantom was created and various phantoms types, one being the anthropomorphic heterogeneous head phantom, were performed using a 7 Tesla human MRI scanner.Echo planar imaging was performed and minimal ghosting and fluctuations were observed using the proposed anthropomorphic phantom. The magnetic field distributions (during MRI experiments at 7 Tesla and the scattering parameter (measured using a network analyzer were most comparable between the anthropomorphic heterogeneous head phantom and an in-vivo human volunteer.The developed anthropomorphic heterogeneous head phantom can be used as a resource to various researchers in applications that involve electromagnetic-biological tissue interactions such as MRI.

Diagnostic value of the flow profile in the distal descending aorta by phase-contrast magnetic resonance for predicting severe coarctation of the aorta.

Science.gov (United States)

Muzzarelli, Stefano; Ordovas, Karen Gomes; Hope, Michael D; Meadows, Jeffery J; Higgins, Charles B; Meadows, Alison Knauth

2011-06-01

To compare aortic flow profiles at the level of the proximal descending (PDAo) and distal descending aorta (DDAo) in patients investigated for coarctation of the aorta (CoA), and compare their respective diagnostic value for predicting severe CoA. Diastolic flow decay in the PDAo predicts severe CoA, but flow measurements at this level are limited by flow turbulence, aliasing, and stent-related artifacts. We studied 49 patients evaluated for CoA with phase contrast magnetic resonance imaging (PC-MRI). Parameters of diastolic flow decay in the PDAo and DDAo were compared. Their respective diagnostic value was compared with the standard reference of transcatheter peak gradient ≥20 mmHg. Flow measurement in the PDAo required repeated acquisition with adjustment of encoding velocity or location of the imaging plane in 69% of patients; measurement in the DDAo was achieved in single acquisition in all cases. Parameters of diastolic flow decay in the PDAo and DDAo, including rate-corrected (RC) deceleration time and RC flow deceleration yielded a good correlation (r = 0.78; P RC deceleration time at DDAo (sensitivity 85%, specificity 85%). Characterization of aortic flow profiles at the DDAo offers a quick and reliable noninvasive means of assessing hemodynamically significant CoA. Copyright © 2011 Wiley-Liss, Inc.

Whole-body voxel phantoms of paediatric patients—UF Series B

Science.gov (United States)

Lee, Choonik; Lee, Choonsik; Williams, Jonathan L.; Bolch, Wesley E.

2006-09-01

Following the previous development of the head and torso voxel phantoms of paediatric patients for use in medical radiation protection (UF Series A), a set of whole-body voxel phantoms of paediatric patients (9-month male, 4-year female, 8-year female, 11-year male and 14-year male) has been developed through the attachment of arms and legs from segmented CT images of a healthy Korean adult (UF Series B). Even though partial-body phantoms (head-torso) may be used in a variety of medical dose reconstruction studies where the extremities are out-of-field or receive only very low levels of scatter radiation, whole-body phantoms play important roles in general radiation protection and in nuclear medicine dosimetry. Inclusion of the arms and legs is critical for dosimetry studies of paediatric patients due to the presence of active bone marrow within the extremities of children. While the UF Series A phantoms preserved the body dimensions and organ masses as seen in the original patients who were scanned, comprehensive adjustments were made for the Series B phantoms to better match International Commission on Radiological Protection (ICRP) age-interpolated reference body masses, body heights, sitting heights and internal organ masses. The CT images of arms and legs of a Korean adult were digitally rescaled and attached to each phantom of the UF series. After completion, the resolutions of the phantoms for the 9-month, 4-year, 8-year, 11-year and 14-year were set at 0.86 mm × 0.86 mm × 3.0 mm, 0.90 mm × 0.90 mm × 5.0 mm, 1.16 mm × 1.16 mm × 6.0 mm, 0.94 mm × 0.94 mm × 6.00 mm and 1.18 mm × 1.18 mm × 6.72 mm, respectively.

Dosimetric characteristics of water equivalent for two solid water phantoms

International Nuclear Information System (INIS)

Wang Jianhua; Wang Xun; Ren Jiangping

2011-01-01

Objective: To investigate the water equivalent of two solid water phantoms. Methods: The X-ray and electron beam depth-ion curves were measured in water and two solid water phantoms, RW3 and Virtual Water. The water-equivalency correction factors for the two solid water phantoms were compared. We measured and calculated the range sealing factors and the fluence correction factors for the two solid water phantoms in the case of electron beams. Results: The average difference between the measured ionization in solid water phantoms and water was 0.42% and 0.16% on 6 MV X-ray (t=-6.15, P=0.001 and t=-1.65, P=0.419) and 0.21% and 0.31% on 10 MV X-ray (t=1.728, P=0.135 and t=-2.296, P=0.061), with 17.4% and 14.5% on 6 MeV electron beams (t=-1.37, P=0.208 and t=-1.47, P=0.179) and 7.0% and 6.0% on 15 MeV electron beams (t=-0.58, P=0.581 and t=-0.90, P=0.395). The water-equivalency correction factors for the two solid water phantoms varied slightly largely, F=58.54, P=0.000 on 6 MV X-ray, F=0.211, P=0.662 on 10 MV X-ray, F=0.97, P=0.353 on 6 MeV electron beams, F=0.14, P=0.717 on 15 MeV electron beams. However, they were almost equal to 1 near the reference depths. The two solid water phantoms showed a similar tread of C pl increasing (F=26.40, P=0.014) and h pl decreasing (F=7.45, P=0.072) with increasing energy. Conclusion: The solid water phantom should undergo a quality control test before being clinical use. (authors)

Rates of in vivo (arterial) and in vitro biocorrosion for pure magnesium.

Science.gov (United States)

Bowen, Patrick K; Drelich, Adam; Drelich, Jaroslaw; Goldman, Jeremy

2015-01-01

The development of magnesium-based materials for bioabsorbable stents relies heavily on corrosion testing by immersion in pseudophysiological solutions, where magnesium degrades faster than it does in vivo. The quantitative difference in corrosion kinetics in vitro and in vivo is largely unknown, but, if determined, would help reduce dependence on animal models. In order to create a quantitative in vitro-in vivo correlation based on an accepted measure of corrosion (penetration rate), commercially pure magnesium wires were corroded in vivo in the abdominal aortas of rats for 5-32 days, and in vitro for up to 14 days using Dulbecco's modified eagle medium. Cross-sectioning, scanning electron microscopy, image analysis, a modified penetration rate tailored to degraded wires, and empirical modeling were used to analyze the corroded specimens. In vitro penetration rates were consistently higher than comparable in vivo rates by a factor of 1.2-1.9× (±0.2×). For a sample <20% corroded, an approximate in vitro-in vivo multiplier of 1.3 ± 0.2× was applied, whereas a multiplier of 1.8 ± 0.2× became appropriate when the magnesium specimen was 25-35% degraded. © 2014 Wiley Periodicals, Inc.

Coartación de la aorta: una revisión sistemática

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O Ruíz Pérez

2015-07-01

Full Text Available La coartación de la aorta es una patología caracterizada por el estrechamiento de la arteria aorta, con la consecuente obstrucción de su flujo; localizada con mayor frecuencia a nivel de aorta torácica descendente distal al origen de la subclavia izquierda, y en la pared posterior de la arteria. Supone aproximadamente el 5,1% (3-10% de las cardiopatías congénitas y constituye la octava malformación cardiaca por orden de frecuencia. La presentación clínica de la coartación aórtica es muy variada y depende de la severidad de la lesión y de su posible asociación con otras anomalías cardiacas. Se resalta la tipo infantil y tipo adulto, siendo la primera la que reviste mayor morbimortalidad. La ecocardiografía bidimensional y la ecocardiografía doppler son el método diagnóstico fundamental para la coartación aórtica. La angiorresonancia magnética (angio-RM contrastada, permite hacer una evaluación detallada de la aorta mediante una reconstrucción tridimensional que muestra claramente sus defectos. Por su parte, la TAC multicorte permite la visualización tridimensional del arco desde múltiples planos, pero como inconveniente tiene la emisión de radiación. El cateterismo cardiaco, constituye más que un medio diagnóstico, uno terapéutico en el cual, no sólo se demuestra la localización y extensión de la zona coartada, la presencia de lesiones asociadas y/o de circulación colateral, sino que permite la obtención de un conocimiento fiable de la severidad y repercusión hemodinámica de la misma. El tratamiento de esta patología, puede ser inicialmente médico, pero de forma definitiva por cateterismo cardíaco intervencionista y con menor frecuencia corrección quirúrgica.

Early and effective use of ketamine for treatment of phantom limb pain

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Harsha Shanthanna

2010-01-01

Full Text Available Treatment for phantom limb pain is difficult and challenging. There is often suboptimum treatment with fewer than 10% receiving lasting relief. Treatments based broadly on other neuropathic pains may not be appropriate for a clinical success. We report a case of phantom limb pain, which proved resistant to multiple analgesics, including opioids and continuous epidural blockade. Treatment with intravenous (IV ketamine as an alternate day infusion, gave complete remission of phantom limb pain. This demonstrates an early and effective use of a potent NMDA antagonist for treatment of phantom limb pain. Mechanisms underlying phantom limb pain are briefly discussed.

Morphological description of collateral branches from the abdominal aorta of lesser anteater (Tamandua tetradactyla

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Breno Costa Macedo

2013-03-01

Full Text Available Tamandua tetradactyla, Xenarthra, is a native species from South America which, due to the few number of studies on its biology, still has many unknown aspects in its morphology. Taking into account the importance of morphological data for various studies, this paper aimed to elucidate the branching of the abdominal aorta in this species to foster the development of further studies. To do this, 4 specimens were used, 2 male and 2 female, all young, from the Bauxite Mine – Paragominas, Para, Brazil, donated after death due to running over to the Animal Morphology Research Laboratory (LaPMA of Universidade Federal Rural da Amazonia (UFRA. The arterial system was filled with contrasted latex and the animals were fixed in a formaldehyde solution (10%, and then dissected, in order to evidence the abdominal aorta and its collateral branches. The parietal branches consisted of 1 pair of caudal phrenic arteries, 2 pairs of intercostal arteries, and 3 pairs of lumbar arteries. Among the visceral branches, stood out: celiac artery; cranial mesenteric artery; adrenal arteries; renal arteries; caudal mesenteric artery; and external, internal, and median sacral iliac arteries, formed from the final portion of the abdominal aorta. Testicular and ovarian arteries originated from the renal arteries, differing from that described in various species.

Serum lipid profile and inflammatory markers in the aorta of cholesterol-fed rats supplemented with extra virgin olive oil, sunflower oils and oil-products.

Science.gov (United States)

Katsarou, Ageliki I; Kaliora, Andriana C; Papalois, Apostolos; Chiou, Antonia; Kalogeropoulos, Nick; Agrogiannis, George; Andrikopoulos, Nikolaos K

2015-01-01

Extra virgin olive oil (EVOO) major and minor component anti-inflammatory effect on aorta was evaluated; Wistar rats were fed (9 weeks) on either a high-cholesterol diet (HCD) or a HCD supplemented with oils, i.e. EVOO, sunflower oil (SO), high-oleic sunflower oil (HOSO), or oil-products modified to their phenolic content, i.e. phenolics deprived-EVOO [EVOO(-)], SO enriched with the EVOO phenolics [SO(+)], HOSO enriched with the EVOO phenolics [HOSO(+)]. HCD induced dyslipidemia and resulted in higher aorta adhesion molecules levels at euthanasia. Groups receiving EVOO, EVOO(-), HOSO, HOSO(+) presented higher serum TC and LDL-c levels compared to cholesterol-fed rats; attenuation of aorta E-selectin levels was also observed. In EVOO/EVOO(-) groups, aorta vascular endothelial adhesion molecule-1 (VCAM-1) was lower compared to HCD animals. SO/SO(+) diets had no effect on endothelial dysfunction amelioration. Overall, our results suggest that major and/or minor EVOO constituents improve aorta E-selectin and VCAM-1, while serum lipids do not benefit.

Neutron measurements with a tissue-equivalent phantom

Energy Technology Data Exchange (ETDEWEB)

Smith, J W [Health Physics Division, Atomic Energy Establishment, Harwell (United Kingdom)

1962-03-15

This Appendix 3E of the dosimetry experiment at the R-B reactor describes the apparatus used and presents the obtained results. The phantom used was a 1/4-inch thick polythene container, 60 cm high, of elliptical cross-section, with a major axis of 36 cm and a minor axis of 20 cm. This was filled with an approximately tissue-equivalent liquid. A light but rigid internal framework of Perspex supported a series of small detectors through the phantom. The detectors used in the first high-level run at Vinca, to measure flux above 0.5 MeV, were 0.5-cm wide track plates wrapped in cadmium foil. Each track plate was a sandwich of two Ilford El 50 - mu emulsions, with glass backing, separated by a 250-mu polythene radiator, and was oriented at an angle of 45 deg to the front surface of the phantom. Under these conditions the response is constant with neutron energy between 0.5 MeV and 8 MeV at 1.26 X 10 sup - sup 3 tracks/neutron to within +- 15%. The detectors used in the second high-level run were gold foils (260 mg/cm sup 2 thick) for determination of the show neutron distribution. Previous experiments with 0.13 MeV, 2.5 MeV, 14 MeV and Po-Be neutrons have shown that the shape of the curve through a phantom obtained from these gold foils is the same as that given by either manganese foils or sodium samples despite the difference in resonance integrals. From the relaxation length of the neutron flux in the phantom, as measured by the track plates, the mean energy of the neutrons with energies greater than 0.5 MeV may be found by comparison with the relaxation lengths obtained by irradiation of the phantom with monoenergetic neutrons. The results of these experiments are given. Track plate results from the Vinca experiment are shown. It can be seen that the backscattered fast flux is about one-third of the incident fast flux and that the energy indicated by the shape of the curve is considerably lower than the energy of the direct neutrons. It seems possible that the high

Neutron measurements with a tissue-equivalent phantom

Energy Technology Data Exchange (ETDEWEB)

Smith, J W [Health Physics Division, Atomic Energy Establishment, Harwell (United Kingdom)

1962-03-01

This Appendix 3E of the dosimetry experiment at the R-B reactor describes the apparatus used and presents the obtained results. The phantom used was a 1/4-inch thick polythene container, 60 cm high, of elliptical cross-section, with a major axis of 36 cm and a minor axis of 20 cm. This was filled with an approximately tissue-equivalent liquid. A light but rigid internal framework of Perspex supported a series of small detectors through the phantom. The detectors used in the first high-level run at Vinca, to measure flux above 0.5 MeV, were 0.5-cm wide track plates wrapped in cadmium foil. Each track plate was a sandwich of two Ilford El 50 - {mu} emulsions, with glass backing, separated by a 250-{mu} polythene radiator, and was oriented at an angle of 45 deg to the front surface of the phantom. Under these conditions the response is constant with neutron energy between 0.5 MeV and 8 MeV at 1.26 X 10{sup -3} tracks/neutron to within {+-} 15%. The detectors used in the second high-level run were gold foils (260 mg/cm{sup 2} thick) for determination of the show neutron distribution. Previous experiments with 0.13 MeV, 2.5 MeV, 14 MeV and Po-Be neutrons have shown that the shape of the curve through a phantom obtained from these gold foils is the same as that given by either manganese foils or sodium samples despite the difference in resonance integrals. From the relaxation length of the neutron flux in the phantom, as measured by the track plates, the mean energy of the neutrons with energies greater than 0.5 MeV may be found by comparison with the relaxation lengths obtained by irradiation of the phantom with monoenergetic neutrons. The results of these experiments are given. Track plate results from the Vinca experiment are shown. It can be seen that the backscattered fast flux is about one-third of the incident fast flux and that the energy indicated by the shape of the curve is considerably lower than the energy of the direct neutrons. It seems possible that the

Energy-Efficient Resource Allocation for Phantom Cellular Networks with Imperfect CSI

KAUST Repository

Abdelhady, Amr Mohamed Abdelaziz

2017-03-28

Multi-tier heterogeneous networks have become an essential constituent for next generation cellular networks. Meanwhile, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for a two-tier phantom cellular network, The optimization framework includes both EE and SE. We consider densely deployed phantom cellular networks and model the EE optimization problem taking into consideration the inevitable interference in this setup and imperfect channel estimation impairments. To this end, we propose three resource allocation strategies aiming at optimizing this network EE performance metric. Furthermore, we investigate the effect of changing some system parameters on the performance of these strategies, such as phantom cells resource units share, number of deployed phantom cells within a macro cell , number of pilots, and the phantom cells transmission power budget. It is found that increasing the number of pilots will deteriorate the EE performance of the whole setup, while increasing phantom cells transmission power budget will not affect the EE of the whole setup significantly. In addition, we observed that it is always useful to allocate most of the network resource units to the phantom cells tier.

Energy-Efficient Resource Allocation for Phantom Cellular Networks with Imperfect CSI

KAUST Repository

Abdelhady, Amr Mohamed Abdelaziz; Amin, Osama; Alouini, Mohamed-Slim

2017-01-01

Multi-tier heterogeneous networks have become an essential constituent for next generation cellular networks. Meanwhile, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for a two-tier phantom cellular network, The optimization framework includes both EE and SE. We consider densely deployed phantom cellular networks and model the EE optimization problem taking into consideration the inevitable interference in this setup and imperfect channel estimation impairments. To this end, we propose three resource allocation strategies aiming at optimizing this network EE performance metric. Furthermore, we investigate the effect of changing some system parameters on the performance of these strategies, such as phantom cells resource units share, number of deployed phantom cells within a macro cell , number of pilots, and the phantom cells transmission power budget. It is found that increasing the number of pilots will deteriorate the EE performance of the whole setup, while increasing phantom cells transmission power budget will not affect the EE of the whole setup significantly. In addition, we observed that it is always useful to allocate most of the network resource units to the phantom cells tier.

COMPORTAMIENTO MECANICO DE LA AORTA ASCENDENTE: CARACTERZACION EXPERIMENTAL Y SIMULACION NUMERICA.

OpenAIRE

GARCIA HERRERA, CLAUDIO; GARCIA HERRERA, CLAUDIO

2008-01-01

En este trabajo se realiza una caracterización experimental y numérica del comportamiento mecánico de la pared de la aorta humana. Se destaca la importancia (le este tema debido al creciente interés cii coiiocer las propiedades y la respuesta mecánica de 193p.

A comparison of age-related changes in axial prestretch in human carotid arteries and in human abdominal aorta.

Science.gov (United States)

Horný, Lukáš; Adámek, Tomáš; Kulvajtová, Markéta

2017-02-01

It is known that large arteries in situ are subjected to significant axial prestretch. This prestretch plays an important physiological role in optimizing the biomechanical response of an artery. It is also known that the prestretch declines with age. However, a detailed description of age-related changes in prestretch is available only for the abdominal aorta and for the femoropliteal artery. Our study presents results of measurements of axial prestretch in 229 left common carotid arteries excised in autopsies. It was found that the prestretch of the carotid artery correlates significantly with age ([Formula: see text], p value Wilcoxon signed-rank test) and simultaneously that carotid media contains a lower number of elastic membranes (median/IQR: 26.5/11.8 vs. 31.5/11.8, [Formula: see text] in the Wilcoxon signed-rank test). This could be a reason for the different extent of the prestretch observed in aorta and in carotid artery. Our data sample also contains 5 measurements of the axial prestretch in abdominal aortas suffering from an aneurysm. It was found that aneurysmatic aortas also exhibit axial retraction when excised from in situ position. To the best of our knowledge, this is the first time that detailed data characterizing axial prestretch of the human left common carotid artery have been presented.

Hydroxytyrosol and its complex forms (secoiridoids) modulate aorta and heart proteome in healthy rats: Potential cardio-protective effects.

Science.gov (United States)

Catalán, Úrsula; Rubió, Laura; López de Las Hazas, Maria-Carmen; Herrero, Pol; Nadal, Pedro; Canela, Núria; Pedret, Anna; Motilva, Maria-José; Solà, Rosa

2016-10-01

Hydroxytyrosol (HT) is the major phenolic compound in virgin olive oil (VOO) in both free and complex forms (secoiridoids; SEC). Proteomics of cardiovascular tissues such as aorta or heart represents a promising tool to uncover the mechanisms of action of phenolic compounds in healthy animals. Twelve female Wistar rats were separated into three groups: a standard diet and two diets supplemented in phenolic compounds (HT and SEC) adjusted to 5 mg/kg/day during 21 days. Proteomic analyses of aorta and heart tissues were performed by nano-LC and MS. Ingenuity Pathway Analysis was used to generate interaction networks. HT or SEC modulated aorta and heart proteome compared to the standard diet. The top-scored networks were related to Cardiovascular System. HT and SEC downregulated proteins related to proliferation and migration of endothelial cells and occlusion of blood vessels in aorta and proteins related to heart failure in heart tissue. SEC showed higher fold change values compared to HT, attributed to higher concentration of HT detected in heart tissue. Changes at proteomic level in cardiovascular tissues may partially account for the underlying mechanisms of VOO phenols cardiovascular protection being the SEC effects higher than free HT. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reversible induction of phantom auditory sensations through simulated unilateral hearing loss.

Directory of Open Access Journals (Sweden)

Roland Schaette

Full Text Available Tinnitus, a phantom auditory sensation, is associated with hearing loss in most cases, but it is unclear if hearing loss causes tinnitus. Phantom auditory sensations can be induced in normal hearing listeners when they experience severe auditory deprivation such as confinement in an anechoic chamber, which can be regarded as somewhat analogous to a profound bilateral hearing loss. As this condition is relatively uncommon among tinnitus patients, induction of phantom sounds by a lesser degree of auditory deprivation could advance our understanding of the mechanisms of tinnitus. In this study, we therefore investigated the reporting of phantom sounds after continuous use of an earplug. 18 healthy volunteers with normal hearing wore a silicone earplug continuously in one ear for 7 days. The attenuation provided by the earplugs simulated a mild high-frequency hearing loss, mean attenuation increased from 30 dB at 3 and 4 kHz. 14 out of 18 participants reported phantom sounds during earplug use. 11 participants presented with stable phantom sounds on day 7 and underwent tinnitus spectrum characterization with the earplug still in place. The spectra showed that the phantom sounds were perceived predominantly as high-pitched, corresponding to the frequency range most affected by the earplug. In all cases, the auditory phantom disappeared when the earplug was removed, indicating a causal relation between auditory deprivation and phantom sounds. This relation matches the predictions of our computational model of tinnitus development, which proposes a possible mechanism by which a stabilization of neuronal activity through homeostatic plasticity in the central auditory system could lead to the development of a neuronal correlate of tinnitus when auditory nerve activity is reduced due to the earplug.

Alderson-Rando phantom 'voxelization' for use in numerical dosimetry

International Nuclear Information System (INIS)

Santos, A.M.; Vieira, J.W.

2008-01-01

This paper presents the methodology used for creating a voxel phantom from the tomographic physical Alderson-Rando phantom images (HR) and to develop a computer model formed by exposure of the resulting phantom 'voxelization' of AR coupled to the Monte Carlo code EGS4 plus algorithms to simulate radioactive sources in internal dosimetry

Lung, aorta, and platelet metabolism of 14C-arachidonic acid in vitamin E deficient rats

International Nuclear Information System (INIS)

Valentovic, M.A.; Gairola, C.; Lubawy, W.C.

1982-01-01

14 C-arachidonic acid metabolism was determined in aortas, platelets, and perfused lungs from rats pair fed a basal diet supplemented with 0 or 100 ppm vitamin E for 11 weeks. Spontaneous erythrocyte hemolysis tests showed 92% and 8% hemolysis for the 0 and 100 ppm vitamin E groups, respectively. Elevated lung homogenate levels of malonaldehyde in the 0 ppm group confirmed its deficient vitamin E status. Aortas from the vitamin E deficient group synthesized 54% less prostacyclin than aortas from the supplemented group (p less than 0.05). Although thromboxane generation by platelets from the vitamin E deficient group exhibited a 37% increase, this difference was not statistically significant compared to the supplemented animals. Greater amounts of PGE2, PGF2 alpha, TXB2, and 6-keto-PGF1 alpha were obtained in albumin buffer perfusates from lungs of vitamin E deficient rats than in those from supplemented rats. Significant differences (p less than 0.05) were noticed, however, only for PGE2 and PGF2 alpha. These studies indicate that vitamin E quantitatively alters arachidonic acid metabolism in aortic and lung tissue but its effect on thromboxane synthesis by platelets is less marked

Dosimetric study on head CT scans using adult and newborn phantoms

International Nuclear Information System (INIS)

Paiva de O, G. A.; Prata M, A.

2016-10-01

Computed tomography is the radiodiagnostic method that most contributes to the dose deposition in population. Therefore, the dose reductions used in these tests are very important, especially for pediatric patients who have a life expectancy greater than the rest of the population. This study purpose to compare the doses generated from newborns compared to adult patients in head computed tomography scans. Two head phantoms in a cylindrical shape made in PMMA were used, one to adult and another to newborn patient dimensions. The pediatric routine scan protocol from a radiological service was used for the computed tomography scans. They were performed in General Electric Computed Tomography scanner, Bright Speed model with 4 channels. The absorbed dose measurements were performed with a pencil chamber placed into both phantoms. The newborn head phantom was developed in order to compare the amount of absorbed dose by the phantoms when it is used the same acquisition protocol. The dose found for newborn phantom was 29.9% higher than the adult phantom. (Author)

Dosimetric study on head CT scans using adult and newborn phantoms

Energy Technology Data Exchange (ETDEWEB)

Paiva de O, G. A.; Prata M, A., E-mail: giovanni_paiva@hotmail.com [Universidade Federal de Minas Gerais, Departamento de Engenharia Nuclear, Av. Pte. Antonio Carlos 6627, 31270-901 Pampulha, Belo Horizonte, Minas Gerais (Brazil)

2016-10-15

Computed tomography is the radiodiagnostic method that most contributes to the dose deposition in population. Therefore, the dose reductions used in these tests are very important, especially for pediatric patients who have a life expectancy greater than the rest of the population. This study purpose to compare the doses generated from newborns compared to adult patients in head computed tomography scans. Two head phantoms in a cylindrical shape made in PMMA were used, one to adult and another to newborn patient dimensions. The pediatric routine scan protocol from a radiological service was used for the computed tomography scans. They were performed in General Electric Computed Tomography scanner, Bright Speed model with 4 channels. The absorbed dose measurements were performed with a pencil chamber placed into both phantoms. The newborn head phantom was developed in order to compare the amount of absorbed dose by the phantoms when it is used the same acquisition protocol. The dose found for newborn phantom was 29.9% higher than the adult phantom. (Author)

Deep brain stimulation for phantom limb pain.

Science.gov (United States)

Bittar, Richard G; Otero, Sofia; Carter, Helen; Aziz, Tipu Z

2005-05-01

Phantom limb pain is an often severe and debilitating phenomenon that has been reported in up to 85% of amputees. Its pathophysiology is poorly understood. Peripheral and spinal mechanisms are thought to play a role in pain modulation in affected individuals; however central mechanisms are also likely to be of importance. The neuromatrix theory postulates a genetically determined representation of body image, which is modified by sensory input to create a neurosignature. Persistence of the neurosignature may be responsible for painless phantom limb sensations, whereas phantom limb pain may be due to abnormal reorganisation within the neuromatrix. This study assessed the clinical outcome of deep brain stimulation of the periventricular grey matter and somatosensory thalamus for the relief of chronic neuropathic pain associated with phantom limb in three patients. These patients were assessed preoperatively and at 3 month intervals postoperatively. Self-rated visual analogue scale pain scores assessed pain intensity, and the McGill Pain Questionnaire assessed the quality of the pain. Quality of life was assessed using the EUROQOL EQ-5D scale. Periventricular gray stimulation alone was optimal in two patients, whilst a combination of periventricular gray and thalamic stimulation produced the greatest degree of relief in one patient. At follow-up (mean 13.3 months) the intensity of pain was reduced by 62% (range 55-70%). In all three patients, the burning component of the pain was completely alleviated. Opiate intake was reduced in the two patients requiring morphine sulphate pre-operatively. Quality of life measures indicated a statistically significant improvement. This data supports the role for deep brain stimulation in patients with phantom limb pain. The medical literature relating to the epidemiology, pathogenesis, and treatment of this clinical entity is reviewed in detail.

Reconstruction of voxel phantoms for skin dosimetry

International Nuclear Information System (INIS)

Antunes, Paula Cristina Guimaraes

2010-01-01

Radiotherapy is a therapeutic modality that utilizes ionizing radiation for the destruction of neoplastic human cells. One of the requirements for this treatment methodology success lays on the appropriate use of planning systems, which performs, among other information, the patient's dose distribution estimate. Nowadays, transport codes have been providing huge subsidies to these planning systems, once it enables specific and accurate patient organ and tissue dosimetry. The model utilized by these codes to describe the human anatomy in a realistic way is known as voxel phantoms, which are represented by discrete volume elements (voxels) directly associated to tomographic data. Nowadays, voxel phantoms doable of being inserted and processed by the transport code MCNP (Monte Carlo N-Particle) presents a 3-4 mm image resolution; however, such resolution limits some thin body structure discrimination, such as skin. In this context, this work proposes a calculus routine that discriminates this region with thickness and localization in the voxel phantoms similar to the real, leading to an accurate dosimetric skin dose assessment by the MCNP code. Moreover, this methodology consists in manipulating the voxel phantoms volume elements by segmenting and subdividing it in different skin thickness. In addition to validate the skin dose calculated data, a set of experimental evaluations with thermoluminescent dosimeters were performed in an anthropomorphic phantom. Due to significant differences observed on the dose distribution of several skin representations, it was found that is important to discriminate the skin thickness similar to the real. The presented methodology is useful to obtain an accurate skin dosimetric evaluation for several radiotherapy procedures, with particular interest on the electron beam radiotherapy, in which highlights the whole body irradiation therapy (TSET), a procedure under implementation at the Hospital das Clinicas da Faculdade de Medicina da

Skin and cutaneous melanocytic lesion simulation in biomedical optics with multilayered phantoms

Energy Technology Data Exchange (ETDEWEB)

Urso, P [Department of Occupational and Environmental Health, Hospital L. Sacco Unit, University of Milan, Via G B Grassi, 74-20157 Milan (Italy); Lualdi, M [Medical Physics Unit, Istituto Nazionale per lo Studio e la Cura dei Tumori, Via Venezian 1-20133 Milan (Italy); Colombo, A [Medical Physics Unit, Istituto Nazionale per lo Studio e la Cura dei Tumori, Via Venezian 1-20133 Milan (Italy); Carrara, M [Medical Physics Unit, Istituto Nazionale per lo Studio e la Cura dei Tumori, Via Venezian 1-20133 Milan (Italy); Tomatis, S [Medical Physics Unit, Istituto Nazionale per lo Studio e la Cura dei Tumori, Via Venezian 1-20133 Milan (Italy); Marchesini, R [Medical Physics Unit, Istituto Nazionale per lo Studio e la Cura dei Tumori, Via Venezian 1-20133 Milan (Italy)

2007-05-21

The complex inner layered structure of skin influences the photon diffusion inside the cutaneous tissues and determines the reflectance spectra formation. Phantoms are very useful tools to understand the biophysical meaning of parameters involved in light propagation through the skin. To simulate the skin reflectance spectrum, we realized a multilayered skin-like phantom and a multilayered skin phantom with a melanoma-like phantom embedded inside. Materials used were Al{sub 2}O{sub 3} particles, melanin of sepia officinalis and a calibrator for haematology systems dispersed in transparent silicon. Components were optically characterized with indirect techniques. Reflectance phantom spectra were compared with average values of in vivo spectra acquired on a sample of 573 voluntary subjects and 132 pigmented lesions. The phantoms' reflectance spectra agreed with those measured in vivo, mimicking the optical behaviour of the human skin. Further, the phantoms were optically stable and easily manageable, and represented a valid resource in spectra formation comprehension, in diagnostic laser applications and simulation model implementation, such as the Monte Carlo code for non-homogeneous media. (note)

Skin and cutaneous melanocytic lesion simulation in biomedical optics with multilayered phantoms

International Nuclear Information System (INIS)

Urso, P; Lualdi, M; Colombo, A; Carrara, M; Tomatis, S; Marchesini, R

2007-01-01

The complex inner layered structure of skin influences the photon diffusion inside the cutaneous tissues and determines the reflectance spectra formation. Phantoms are very useful tools to understand the biophysical meaning of parameters involved in light propagation through the skin. To simulate the skin reflectance spectrum, we realized a multilayered skin-like phantom and a multilayered skin phantom with a melanoma-like phantom embedded inside. Materials used were Al 2 O 3 particles, melanin of sepia officinalis and a calibrator for haematology systems dispersed in transparent silicon. Components were optically characterized with indirect techniques. Reflectance phantom spectra were compared with average values of in vivo spectra acquired on a sample of 573 voluntary subjects and 132 pigmented lesions. The phantoms' reflectance spectra agreed with those measured in vivo, mimicking the optical behaviour of the human skin. Further, the phantoms were optically stable and easily manageable, and represented a valid resource in spectra formation comprehension, in diagnostic laser applications and simulation model implementation, such as the Monte Carlo code for non-homogeneous media. (note)

Pulmonary arterial hypertension in children: diagnosis using ratio of main pulmonary artery to ascending aorta diameter as determined by multi-detector computed tomography.

Science.gov (United States)

Caro-Domínguez, Pablo; Compton, Gregory; Humpl, Tilman; Manson, David E

2016-09-01

The ratio of the transverse diameter of the main pulmonary artery (MPA) to ascending aorta as determined at multi-detector CT is a tool that can be used to assess the pulmonary arterial size in cases of pulmonary arterial hypertension in children. To establish a ratio of MPA to ascending aorta diameter using multi-detector CT imaging suggestive of pulmonary arterial hypertension in children. We hypothesize that a defined ratio of MPA to ascending aorta is identifiable on multi-detector CT and that higher ratios can be used to reliably diagnose the presence of pulmonary arterial hypertension in children. We calculated the multi-detector CT ratio of MPA to ascending aorta diameter in 44 children with documented pulmonary arterial hypertension by right heart catheterization and in 44 age- and gender-matched control children with no predisposing factors for pulmonary arterial hypertension. We compared this multi-detector-CT-determined ratio with the MPA pressure in the study group, as well as with the ratio of MPA to ascending aorta in the control group. A threshold ratio value was calculated to accurately identify children with pulmonary arterial hypertension. Children with documented primary pulmonary arterial hypertension have a significantly higher ratio of MPA to ascending aorta (1.46) than children without pulmonary arterial hypertension (1.11). A ratio of 1.3 carries a positive likelihood of 34 and a positive predictive value of 97% for the diagnosis of pulmonary arterial hypertension. The pulmonary arteries were larger in children with pulmonary arterial hypertension than in a control group of normal children. A CT-measured ratio of MPA to ascending aorta of 1.3 should raise the suspicion of pulmonary arterial hypertension in children.

Realistic deformable 3D numeric phantom for transcutaneous ultrasound

Energy Technology Data Exchange (ETDEWEB)

Cardoso, Fernando Mitsuyama; Moraes, Matheus Cardoso; Furuie, Sergio Shiguemi, E-mail: fernando.okara@gmail.com [Universidade de Sao Paulo (USP), SP (Brazil). Escola de Engenharia

2017-01-15

Introduction: Numerical phantoms are important tools to design, calibrate and evaluate several methods in various image-processing applications, such as echocardiography and mammography. We present a framework for creating ultrasound numerical deformable phantoms based on Finite Element Method (FEM), Linear Isomorphism and Field II. The proposed method considers that the scatterers map is a property of the tissue; therefore, the scatterers should move according to the tissue strain. Methods: First, a volume representing the target tissue is loaded. Second, parameter values, such as Young's Modulus, scatterers density, attenuation and scattering amplitudes are inserted for each different regions of the phantom. Then, other parameters related to the ultrasound equipment, such as ultrasound frequency and number of transducer elements, are also defined in order to perform the ultrasound acquisition using Field II. Third, the size and position of the transducer and the pressures that are applied against the tissue are defined. Subsequently, FEM is executed and deformation is computed. Next, 3D linear isomorphism is performed to displace the scatterers according to the deformation. Finally, Field II is carried out to generate the non-deformed and deformed ultrasound data. Results: The framework is evaluated by comparing strain values obtained the numerical simulation and from the physical phantom from CIRS. The mean difference between both phantoms is lesser than 10%. Conclusion: The acoustic and deformation outcomes are similar to those obtained using a physical phantom. This framework led to a tool, which is available online and free of charges for educational and research purposes. (author)

Hybrid computational phantoms of the male and female newborn patient: NURBS-based whole-body models

International Nuclear Information System (INIS)

Lee, Choonsik; Lodwick, Daniel; Hasenauer, Deanna; Williams, Jonathan L; Lee, Choonik; Bolch, Wesley E

2007-01-01

Anthropomorphic computational phantoms are computer models of the human body for use in the evaluation of dose distributions resulting from either internal or external radiation sources. Currently, two classes of computational phantoms have been developed and widely utilized for organ dose assessment: (1) stylized phantoms and (2) voxel phantoms which describe the human anatomy via mathematical surface equations or 3D voxel matrices, respectively. Although stylized phantoms based on mathematical equations can be very flexible in regard to making changes in organ position and geometrical shape, they are limited in their ability to fully capture the anatomic complexities of human internal anatomy. In turn, voxel phantoms have been developed through image-based segmentation and correspondingly provide much better anatomical realism in comparison to simpler stylized phantoms. However, they themselves are limited in defining organs presented in low contrast within either magnetic resonance or computed tomography images-the two major sources in voxel phantom construction. By definition, voxel phantoms are typically constructed via segmentation of transaxial images, and thus while fine anatomic features are seen in this viewing plane, slice-to-slice discontinuities become apparent in viewing the anatomy of voxel phantoms in the sagittal or coronal planes. This study introduces the concept of a hybrid computational newborn phantom that takes full advantage of the best features of both its stylized and voxel counterparts: flexibility in phantom alterations and anatomic realism. Non-uniform rational B-spline (NURBS) surfaces, a mathematical modeling tool traditionally applied to graphical animation studies, was adopted to replace the limited mathematical surface equations of stylized phantoms. A previously developed whole-body voxel phantom of the newborn female was utilized as a realistic anatomical framework for hybrid phantom construction. The construction of a hybrid

Anthropomorphic phantom materials

International Nuclear Information System (INIS)

White, D.R.; Constantinou, C.

1982-01-01

The need, terminology and history of tissue substitutes are outlined. Radiation properties of real tissues are described and simulation procedures are outlined. Recent tissue substitutes are described and charted, as are calculated radiation classifications. Manufacturing procedures and quality control are presented. Recent phantom studies are reviewed and a discussion recorded. Elemental compositions of the recommended tissue substitutes are charted with elemental composition given for each tissue substitute

Solid water phantom

International Nuclear Information System (INIS)

Arguiropulo, M.Y.; Ghilardi Neto, T.; Pela, C.A.; Ghilardi, A.J.P.

1992-01-01

A phantom were developed for simulating water, based in plastics. The material was evaluated for different energies, and the measures of relative transmission showed that the transmission and the water were inside of 0,6% for gamma rays. The results of this new material were presented, showing that it could be used in photon beam calibration with energies on radiotherapy range. (C.G.C.)

Effect of Graphite Concentration on Shear-Wave Speed in Gelatin-Based Tissue-Mimicking Phantoms

Science.gov (United States)

Anderson, Pamela G.; Rouze, Ned C.; Palmeri, Mark L.

2011-01-01

Elasticity-based imaging modalities are becoming popular diagnostic tools in clinical practice. Gelatin-based, tissue mimicking phantoms that contain graphite as the acoustic scattering material are commonly used in testing and validating elasticity-imaging methods to quantify tissue stiffness. The gelatin bloom strength and concentration are used to control phantom stiffness. While it is known that graphite concentration can be modulated to control acoustic attenuation, the impact of graphite concentrationon phantom elasticity has not been characterized in these gelatin phantoms. This work investigates the impact of graphite concentration on phantom shear stiffness as characterized by shear-wave speed measurements using impulsive acoustic-radiation-force excitations. Phantom shear-wave speed increased by 0.83 (m/s)/(dB/(cm MHz)) when increasing the attenuation coefficient slope of the phantom material through increasing graphite concentration. Therefore, gelatin-phantom stiffness can be affected by the conventional ways that attenuation is modulated through graphite concentration in these phantoms. PMID:21710828

Determination of photon conversion factors relating exposure and dose for several extremity phantom designs

International Nuclear Information System (INIS)

Roberson, P.L.; Eichner, F.N.; Reece, W.D.

1986-09-01

This report presents the results of measurements of dosimetric properties of simple extremity phantoms suitable for use in extremity dosimeter performance testing. Two sizes of phantoms were used in this study. One size represented the forearm or lower leg and the other size represented the finger or toe. For both phantom sizes, measurements were performed on solid plastic phantoms and on phantoms containing simulated bone material to determine the effect of backscattered radiations from the bone on the surface dose. Exposure-to-dose conversion factors (C/sub x/ factors) were determined for photon energies ranging from 16 to 1250 keV (average for 60 Co). The effect of the presence of a phantom was also measured for a 90 Sr/ 90 Y source. Significant differences in the measured C/sub x/ factors were found among the phantoms investigated. The factors for the finger-sized phantoms were uniformly less than for the arm-sized phantoms

Development of a patient-specific two-compartment anthropomorphic breast phantom

International Nuclear Information System (INIS)

Prionas, Nicolas D; Burkett, George W; McKenney, Sarah E; Chen, Lin; Boone, John M; Stern, Robin L

2012-01-01

The purpose of this paper is to develop a technique for the construction of a two-compartment anthropomorphic breast phantom specific to an individual patient's pendant breast anatomy. Three-dimensional breast images were acquired on a prototype dedicated breast computed tomography (bCT) scanner as part of an ongoing IRB-approved clinical trial of bCT. The images from the breast of a patient were segmented into adipose and glandular tissue regions and divided into 1.59 mm thick breast sections to correspond to the thickness of polyethylene stock. A computer-controlled water-jet cutting machine was used to cut the outer breast edge and the internal regions corresponding to glandular tissue from the polyethylene. The stack of polyethylene breast segments was encased in a thermoplastic ‘skin’ and filled with water. Water-filled spaces modeled glandular tissue structures and the surrounding polyethylene modeled the adipose tissue compartment. Utility of the phantom was demonstrated by inserting 200 µm microcalcifications as well as by measuring point dose deposition during bCT scanning. Affine registration of the original patient images with bCT images of the phantom showed similar tissue distribution. Linear profiles through the registered images demonstrated a mean coefficient of determination (r 2 ) between grayscale profiles of 0.881. The exponent of the power law describing the anatomical noise power spectrum was identical in the coronal images of the patient's breast and the phantom. Microcalcifications were visualized in the phantom at bCT scanning. The real-time air kerma rate was measured during bCT scanning and fluctuated with breast anatomy. On average, point dose deposition was 7.1% greater than the mean glandular dose. A technique to generate a two-compartment anthropomorphic breast phantom from bCT images has been demonstrated. The phantom is the first, to our knowledge, to accurately model the uncompressed pendant breast and the glandular tissue

IMRT delivery verification using a spiral phantom

International Nuclear Information System (INIS)

Richardson, Susan L.; Tome, Wolfgang A.; Orton, Nigel P.; McNutt, Todd R.; Paliwal, Bhudatt R.

2003-01-01

In this paper we report on the testing and verification of a system for IMRT delivery quality assurance that uses a cylindrical solid water phantom with a spiral trajectory for radiographic film placement. This spiral film technique provides more complete dosimetric verification of the entire IMRT treatment than perpendicular film methods, since it samples a three-dimensional dose subspace rather than using measurements at only one or two depths. As an example, the complete analysis of the predicted and measured spiral films is described for an intracranial IMRT treatment case. The results of this analysis are compared to those of a single field perpendicular film technique that is typically used for IMRT QA. The comparison demonstrates that both methods result in a dosimetric error within a clinical tolerance of 5%, however the spiral phantom QA technique provides a more complete dosimetric verification while being less time consuming. To independently verify the dosimetry obtained with the spiral film, the same IMRT treatment was delivered to a similar phantom in which LiF thermoluminescent dosimeters were arranged along the spiral trajectory. The maximum difference between the predicted and measured TLD data for the 1.8 Gy fraction was 0.06 Gy for a TLD located in a high dose gradient region. This further validates the ability of the spiral phantom QA process to accurately verify delivery of an IMRT plan

The coral reef aorta - a single centre experience in 70 patients.

Science.gov (United States)

Grotemeyer, Dirk; Pourhassan, Siamak; Rehbein, Hermann; Voiculescu, Adina; Reinecke, Petra; Sandmann, Wilhelm

2007-01-01

Coral reef aorta (CRA) is described as rock-hard calcifications in the visceral part of the aorta. These heavily calcified plaques grow into the lumen and can cause significant stenoses, which may lead to malperfusion of the lower limbs, visceral ischemia or hypertension due to renal ischemia. From January 1984 to February 2007, 70 patients (24 men, 46 women, mean age 59.5 years, range 14 to 81 years) underwent treatment in the Department of Vascular Surgery and Renal Transplantation, University Hospital, Heinrich-Heine-University (Düsseldorf, Germany) for CRA. The present study is based on a review of patients' records and the prospective follow-up in the outpatient clinic. The most frequent finding was renovascular arterial hypertension (44.3%) causing headache, vertigo and visual symptoms. Intermittent claudication due to peripheral arterial occlusive disease was found in 28 patients (40.0%). Seventeen patients (24.3%) presented with chronic visceral ischemia causing diarrhea, weight loss and abdominal pain. Sixty-nine of the 70 patients (98.6%) underwent surgery; in 57 patients, aortic reconstruction was achieved with thromboendarterectomy, performed on an isolated suprarenal segment in six cases (8.7%), an infrarenal segment in 15 cases (21.7%), and the supra- and infrarenal aorta in 43 cases (62.3%). Eight patients (11.6%) died during or soon after surgery. Postoperative complications requiring corrective surgery occurred in 11 patients (15.9%). Almost one-third of the patients (n=19, 27.5%) returned for follow-up after a mean of 52.6 months (range six to 215 months). Of the 19 patients, there was significant clinical and diagnostic improvement in 16 patients (84.2%) and three patients (15.8%) were unchanged. Impairment was not observed. Despite the existing and improving surgical techniques for the treatment of CRA, its pathophysiological basis and genesis is not yet understood.

Design of a phantom multitrous for a gamma camera quality control

International Nuclear Information System (INIS)

Ben Krir, Wafa; Ben Ameur, Narjes

2009-01-01

In this study we presented the technique of scintigraphy in its various theoretical and practical aspects. We have also shown the importance the quality control procedure according to international standards, as NEMA. Starting from different phantoms currently used, developed according to standards, we designed our phantom. On the other part, this implementation has helped to highlight our expectations in Concerning the functionality of the phantom. Indeed, these results were very conclusive since they made it possible to make a very fast cost and quality control without ambiguity lower. We have thus proved the very advanced stage of reliability of our phantom.

Coupled oscillators as models of phantom and scalar field cosmologies

International Nuclear Information System (INIS)

Faraoni, Valerio

2004-01-01

We study a toy model for phantom cosmology recently introduced in the literature and consisting of two oscillators, one of which carries negative kinetic energy. The results are compared with the exact phase space picture obtained for similar dynamical systems describing, respectively, a massive canonical scalar field conformally coupled to the spacetime curvature and a conformally coupled massive phantom. Finally, the dynamical system describing exactly a minimally coupled phantom is studied and compared with the toy model

The design and fabrication of two portal vein flow phantoms by different methods

Energy Technology Data Exchange (ETDEWEB)

Yunker, Bryan E., E-mail: bryan.yunker@ucdenver.edu; Lanning, Craig J.; Shandas, Robin; Hunter, Kendall S. [Department of Bioengineering, University of Colorado – Denver/Anschutz, 12700 East 19th Avenue, MS 8607, Aurora, Colorado 80045 (United States); Dodd, Gerald D., E-mail: gerald.dodd@ucdenver.edu; Chang, Samuel; Scherzinger, Ann L. [Department of Radiology, University of Colorado – SOM, 12401 East 17th Avenue, Mail Stop L954, Aurora, Colorado 80045 (United States); Chen, S. James, E-mail: james.chen@ucdenver.edu [Department of Medicine, University of Colorado Denver, Colorado 80045 and Department of Medicine/Cardiology, University of Colorado – SOM, 12401 East 17th Avenue, Mail Stop B132, Aurora, Colorado 80045 (United States); Feng, Yusheng, E-mail: yusheng.feng@utsa.edu [Department of Mechanical Engineering, University of Texas – San Antonio, One UTSA Circle, Mail Stop: AET 2.332, San Antonio, Texas 78249–0670 (United States)

2014-02-15

Purpose: This study outlines the design and fabrication techniques for two portal vein flow phantoms. Methods: A materials study was performed as a precursor to this phantom fabrication effort and the desired material properties are restated for continuity. A three-dimensional portal vein pattern was created from the Visual Human database. The portal vein pattern was used to fabricate two flow phantoms by different methods with identical interior surface geometry using computer aided design software tools and rapid prototyping techniques. One portal flow phantom was fabricated within a solid block of clear silicone for use on a table with Ultrasound or within medical imaging systems such as MRI, CT, PET, or SPECT. The other portal flow phantom was fabricated as a thin walled tubular latex structure for use in water tanks with Ultrasound imaging. Both phantoms were evaluated for usability and durability. Results: Both phantoms were fabricated successfully and passed durability criteria for flow testing in the next project phase. Conclusions: The fabrication methods and materials employed for the study yielded durable portal vein phantoms.

Pediatric phantoms for use in dosimetric calculations

International Nuclear Information System (INIS)

Shoup, R.L.; Hwang, J.L.; Poston, J.W.; Warner, G.G.

1976-01-01

Estimating absorbed doses to children from external and internal radiation sources has become important to the nuclear industry and pediatric nuclear medicine. The Medical Physics and Internal Dosimetry Section at ORNL has recently completed the design of mathematical representations of children of ages newborn, 1 year, and 5 years old. These mathematical representations will be referred to as pediatric phantoms. Using these phantoms, relevant energy deposition data have been developed which establish a meaningful model for use in estimating radiation dose to children

SU-E-P-59: A Graphical Interface for XCAT Phantom Configuration, Generation and Processing

International Nuclear Information System (INIS)

Myronakis, M; Cai, W; Dhou, S; Cifter, F; Lewis, J; Hurwitz, M

2015-01-01

Purpose: To design a comprehensive open-source, publicly available, graphical user interface (GUI) to facilitate the configuration, generation, processing and use of the 4D Extended Cardiac-Torso (XCAT) phantom. Methods: The XCAT phantom includes over 9000 anatomical objects as well as respiratory, cardiac and tumor motion. It is widely used for research studies in medical imaging and radiotherapy. The phantom generation process involves the configuration of a text script to parameterize the geometry, motion, and composition of the whole body and objects within it, and to generate simulated PET or CT images. To avoid the need for manual editing or script writing, our MATLAB-based GUI uses slider controls, drop-down lists, buttons and graphical text input to parameterize and process the phantom. Results: Our GUI can be used to: a) generate parameter files; b) generate the voxelized phantom; c) combine the phantom with a lesion; d) display the phantom; e) produce average and maximum intensity images from the phantom output files; f) incorporate irregular patient breathing patterns; and f) generate DICOM files containing phantom images. The GUI provides local help information using tool-tip strings on the currently selected phantom, minimizing the need for external documentation. The DICOM generation feature is intended to simplify the process of importing the phantom images into radiotherapy treatment planning systems or other clinical software. Conclusion: The GUI simplifies and automates the use of the XCAT phantom for imaging-based research projects in medical imaging or radiotherapy. This has the potential to accelerate research conducted with the XCAT phantom, or to ease the learning curve for new users. This tool does not include the XCAT phantom software itself. We would like to acknowledge funding from MRA, Varian Medical Systems Inc

SU-E-P-59: A Graphical Interface for XCAT Phantom Configuration, Generation and Processing

Energy Technology Data Exchange (ETDEWEB)

Myronakis, M; Cai, W; Dhou, S; Cifter, F; Lewis, J [Brigham and Women’s Hospital, Boston, MA (United States); Hurwitz, M [Newton, MA (United States)

2015-06-15

Purpose: To design a comprehensive open-source, publicly available, graphical user interface (GUI) to facilitate the configuration, generation, processing and use of the 4D Extended Cardiac-Torso (XCAT) phantom. Methods: The XCAT phantom includes over 9000 anatomical objects as well as respiratory, cardiac and tumor motion. It is widely used for research studies in medical imaging and radiotherapy. The phantom generation process involves the configuration of a text script to parameterize the geometry, motion, and composition of the whole body and objects within it, and to generate simulated PET or CT images. To avoid the need for manual editing or script writing, our MATLAB-based GUI uses slider controls, drop-down lists, buttons and graphical text input to parameterize and process the phantom. Results: Our GUI can be used to: a) generate parameter files; b) generate the voxelized phantom; c) combine the phantom with a lesion; d) display the phantom; e) produce average and maximum intensity images from the phantom output files; f) incorporate irregular patient breathing patterns; and f) generate DICOM files containing phantom images. The GUI provides local help information using tool-tip strings on the currently selected phantom, minimizing the need for external documentation. The DICOM generation feature is intended to simplify the process of importing the phantom images into radiotherapy treatment planning systems or other clinical software. Conclusion: The GUI simplifies and automates the use of the XCAT phantom for imaging-based research projects in medical imaging or radiotherapy. This has the potential to accelerate research conducted with the XCAT phantom, or to ease the learning curve for new users. This tool does not include the XCAT phantom software itself. We would like to acknowledge funding from MRA, Varian Medical Systems Inc.

SU-C-209-07: Phantoms for Digital Breast Tomosynthesis Imaging System Evaluation

Energy Technology Data Exchange (ETDEWEB)

Jacobson, D; Liu, Y [Medical College of Wisconsin, Milwaukee, WI (United States)

2016-06-15

Purpose: Digital Breast Tomosynthesis (DBT) is gaining importance in breast imaging. There is a need for phantoms that can be used for image evaluation and comparison. Existing commercially available phantoms for DBT are expensive and may lack clinically relevant test objects. The purpose of this study is to develop phantoms for DBT evaluation. Methods Four phantoms have been designed and constructed to assess the image quality (IQ) of two DBT systems. The first contains a spiral of 0.3 mm SiC beads in gelatin to measure the tomographic slice thickness profile and uniformity of coverage in a series of tomographic planes. The second contains simulated tumors inclined with respect to the phantom base to assess tomographic image quality. The third has a tilted array of discs with varying contrast and diameter. This phantom was imaged alone and in a stack of TE slabs giving 2 to 10 cm thickness. The fourth has a dual wedge of glandular and adipose simulating materials. One wedge contains discs with varying diameter and thickness; the other supports a mass with six simulated spicules of varying size and a cluster of simulated calcifications. The simulated glandular tissue material varies between 35 and 100% of the total thickness (5.5 cm). Results: All phantoms were scanned successfully. The best IQ comparison was achieved with the dual wedge phantom as demonstrated by the spiculated mass and calcifications. Images were evaluated by two radiologists and one physicist. The projection images and corresponding set of tomographic planes were comparable and the synthesized projection images were inferior to the projection images for both systems. Conclusion: Four phantoms were designed, constructed and imaged on two DBT systems. They successfully demonstrated performance differences between two systems, and between true and synthesized projection images. Future work will incorporate these designs into a single phantom.

Phantom's construction for dose measurement in brachytherapy

International Nuclear Information System (INIS)

Tri Harjanto; Hidayat Joko Puspito; Joko Triyanto

2009-01-01

In nuclear medicine, dose rate validation is the key for a successful process in therapy and diagnose of any deases. Therefore, the brachytherapy equipment being designed and constructed is to be validated its dose rate received by the radiated object. A phantom for such validation purpose is designed and constructed as a correct as if on site geometrical position of sources. The design of phantom consists of seven layers of flexi glass plates: 10 mm thick, 105 mm wide, and 280 mm length. All the plates are to be holed according to the size of the applicator to be used. Every surface of the flexi glass layers is grooved 1 mm wide, 1 mm depth, and 10 mm distance between the groove. The applicator inside the phantom is positioned at a certain reference for measurement. Every TLD installed has a fix position toward the reference coordinate and has an index number. By this system of phantom, the isodose system can be plotted. (author)

Gravitational Quasinormal Modes of Regular Phantom Black Hole

Directory of Open Access Journals (Sweden)

Jin Li

2017-01-01

Full Text Available We investigate the gravitational quasinormal modes (QNMs for a type of regular black hole (BH known as phantom BH, which is a static self-gravitating solution of a minimally coupled phantom scalar field with a potential. The studies are carried out for three different spacetimes: asymptotically flat, de Sitter (dS, and anti-de Sitter (AdS. In order to consider the standard odd parity and even parity of gravitational perturbations, the corresponding master equations are derived. The QNMs are discussed by evaluating the temporal evolution of the perturbation field which, in turn, provides direct information on the stability of BH spacetime. It is found that in asymptotically flat, dS, and AdS spacetimes the gravitational perturbations have similar characteristics for both odd and even parities. The decay rate of perturbation is strongly dependent on the scale parameter b, which measures the coupling strength between phantom scalar field and the gravity. Furthermore, through the analysis of Hawking radiation, it is shown that the thermodynamics of such regular phantom BH is also influenced by b. The obtained results might shed some light on the quantum interpretation of QNM perturbation.

A suitability study of the fission product phantom and the bottle manikin absorption phantom for calibration of in vivo bioassay equipment for the DOELAP accreditation testing program

International Nuclear Information System (INIS)

Olsen, P.C.; Lynch, T.P.

1991-08-01

Pacific Northwest laboratory (PNL) conducted an intercomparison study of the Fission Product phantom and the bottle manikin absorption (BOMAB) phantom for the US Department of Energy (DOE) to determine the consistency of calibration response of the two phantoms and their suitability for certification and use under a planned bioassay laboratory accreditation program. The study was initiated to determine calibration factors for both types of phantoms and to evaluate the suitability of their use in DOE Laboratory Accreditation Program (DOELAP) round-robin testing. The BOMAB was found to be more appropriate for the DOELAP testing program. 9 refs., 9 figs., 9 tabs

Measurement of blood flow in the left ventricle and aorta using clinical 2D cine phase-contrast magnetic resonance imaging

International Nuclear Information System (INIS)

Nakamura, Masanori; Wada, Shigeo; Yokosawa, Suguru; Yamaguchi, Takami; Isoda, Haruo; Takeda, Hiroyasu

2007-01-01

A recent development in phase-contrast magnetic resonance imaging (cine PC-MRI) allows the detailed measurement of the blood flow in humans. The objectives of this study are twofold: to discuss the utility of clinical two-dimensional (2D) cine PC-MRI as a practical tool for analyzing hemodynamics in the aorta and left ventricle; to provide flow information at those places as references for computational fluid dynamics studies. Using 2D cine PC-MRI, we mapped velocity profiles at various cross sections of the aorta and left ventricle. The results illustrated the main flow events in the left ventricle during the cardiac cycle, such as ventricular ejection and suction, while the secondary flows were less clear. The velocity profile at the entrance of the ascending aorta appeared to be slightly skewed posteriorly in early systole, but the flow in the central zone of the section was rapid. The estimated stroke volume, peak Reynolds numbers, and Womersley numbers were within the normal physiological range. A sequence of secondary flow images from the plane of the aortic valve to the descending aorta revealed the evolution of a helical flow within the aorta. Flows entering the aortic branches were captured well. Those results demonstrate that clinical 2D cine PC-MRI is a practical adjunct for analyzing blood flow in vivo and would be useful as references to check validity of flow dynamics obtained by computer simulations. (author)

Development of realistic chest phantom for calibration of in-vivo plutonium counting facilities

International Nuclear Information System (INIS)

Shirotani, Takashi

1987-06-01

We have developed realistic chest phantom with removable model organs. The phantom is a torso and is terminated just above the femoral region. Tissue equivalent materials used in the phantom have been made of polyurethane with different amounts of ester of phosphoric acid, in order to simulate human soft tissues such as muscle, muscle-adipose mixtures and cartilage. Lung simulant has been made of foamed polyurethane. Capsulized small sources can be inserted into the holes, drilled in each sliced section of the model organ. Counting efficiencies, obtained with a pair of 12 cm diameter phoswich detectors set above the phantom chest, are 0.195 cpm/nCi for Pu-239 and 44.07 cpm/nCi for Am-241, respectively. The results agree well with efficiencies obtained with IAEA-Phantom. We conclude that the phantom can be used as a standard phantom for the calibration of Pu chest counting equipment. (author)