Splat-based surface reconstruction from defect-laden point sets

We introduce a method for surface reconstruction from point sets that is able to cope with noise and outliers. First, a splat-based representation is computed from the point set. A robust local 3D RANSAC-based procedure is used to filter the point set for outliers, then a local jet surface - a low-degree surface approximation - is fitted to the inliers. Second, we extract the reconstructed surface in the form of a surface triangle mesh through Delaunay refinement. The Delaunay refinement meshing approach requires computing intersections between line segment queries and the surface to be meshed. In the present case, intersection queries are solved from the set of splats through a 1D RANSAC procedure

Patson Approach versus the Standard Approach for increasing breast reconstruction rates in women undergoing mastectomy. A randomized, controlled, open-label clinical trial

Breast cancer is the most prevalent neoplasm among women in the majority of countries worldwide. Breast cancer treatment include mastectomy which is associated to strong impact in women. Breast reconstruction is an option for many women to re-establish their body image and also to decrease psychological impact. However, breast reconstruction rates are low and many factors are involved in not undergoing breast reconstruction. Patient involvement in the decision-making process increases breast reconstruction rates and is associated to higher satisfaction and less anxiety and depression symptoms. More physician-patient relation and more education in terms of breast reconstruction are needed to achieve our objective. A new approach of medical care, called Patson Approach, is created in order to meet our goal with more patient involvement, as well as, physician and psychological counsellingObjective: to increase breast reconstruction rates in women who are candidates for breast reconstruction after mastectomy and are included in the Patson Approach compared to women included in the Standard ApproachMethods: the study design will be a randomized, controlled, open-label clinical trial. 62 patients will be recruited during two years and randomly divided in two groups, 31 will be included in the Standard Approach and 31 will be included in the Patson Approach. Preoperative and postoperative appointments are established in order to do a follow-up of the patients and collect all the data

CT and PET/CT Hybrid Imaging of Coronary Artery Disease

Coronary artery disease (CAD) is a chronic process that evolves over decades and may culminate in myocardial infarction (MI). While invasive coronary angiography (ICA) is still considered the gold standard of imaging CAD, non-invasive assessment of both the vascular anatomy and myocardial perfusion has become an intriguing alternative. In particular, computed tomography (CT) and positron emission tomography (PET) form an attractive combination for such studies. Increased radiation dose is, however, a concern. Our aim in the current thesis was to test novel CT and PET techniques alone and in hybrid setting in the detection and assessment of CAD in clinical patients. Along with diagnostic accuracy, methods for the reduction of the radiation dose was an important target. The study investigating the coronary arteries of patients with atrial fibrillation (AF) showed that CAD may be an important etiology of AF because a high prevalence of CAD was demonstrated within AF patients. In patients with suspected CAD, we demonstrated that a sequential, prospectively ECG-triggered CT technique was applicable to nearly 9/10 clinical patients and the radiation dose was over 60% lower than with spiral CT. To detect the functional significance of obstructive CAD, a novel software for perfusion quantification, CarimasTM, showed high reproducibility with 15O-labelled water in PET, supporting feasibility and good clinical accuracy. In a larger cohort of 107 patients with moderate 30-70% pre-test probability of CAD, hybrid PET/CT was shown to be a powerful diagnostic method in the assessment of CAD with diagnostic accuracy comparable to that of invasive angiography and fractional flow reserve (FFR) measurements. A hybrid study may be performed with a reasonable radiation dose in a vast majority of the cases, improving the performance of stand-alone PET and CT angiography, particularly when the absolute quantification of the perfusion is employed. These results can be applied into clinical practice and will be useful for daily clinical diagnosis of CAD.

THE LOGICAL SYSTEM OF FREGE'S GRUNDGESTZE: A RATIONAL RECONSTRUCTION

This paper aims at clarifying the nature of Frege's system of logic, as presented in the first volume of the Grundgesetze . We undertake a rational reconstruction of this system, by distinguishing its propositional and predicate fragments. This allows us to emphasise the differences and similarities between this system and a modern system of classical second-order logic.

Lipotoxicity in Obesity and Coronary Artery Disease. Studies by PET, CT and MR

Lipotoxicity is a condition in which fatty acids (FAs) are not efficiently stored in adipose tissue and overflow to non-adipose tissue, causing organ damages. A defect of adipose tissue FA storage capability can be the primary culprit in the insulin resistance condition that characterizes many of the severe metabolic diseases that affect people nowadays. Obesity, in this regard, constitutes the gateway and risk factor of the major killers of modern society, such as cardiovascular disease and cancer. A deep understanding of the pathogenetic mechanisms that underlie obesity and the insulin resistance syndrome is a challenge for modern medicine. In the last twenty years of scientific research, FA metabolism and dysregulations have been the object of numerous studies. Development of more targeted and quantitative methodologies is required on one hand, to investigate and dissect organ metabolism, on the other hand to test the efficacy and mechanisms of action of novel drugs. The combination of functional and anatomical imaging is an answer to this need, since it provides more understanding and more information than we have ever had. The first purpose of this study was to investigate abnormalities of substrate organ metabolism, with special reference to the FA metabolism in obese drug-naïve subjects at an early stage of disease. Secondly, trimetazidine (TMZ), a metabolic drug supposed to inhibit FA oxidation (FAO), has been for the first time evaluated in obese subjects to test a whole body and organ metabolism improvement based on the hypothesis that FAO is increased at an early stage of the disease. A third objective was to investigate the relationship between ectopic fat accumulation surrounding heart and coronaries, and impaired myocardial perfusion in patients with risk of coronary artery disease (CAD). In the current study a new methodology has been developed with PET imaging with 11C-palmitate and compartmental modelling for the non-invasive in vivo study of liver FA metabolism, and a similar approach has been used to study FA metabolism in the skeletal muscle, the adipose tissue and the heart. The results of the different substudies point in the same direction. Obesity, at the an early stage, is associated with an impairment in the esterification of FAs in adipose tissue and skeletal muscle, which is accompanied by the upregulation in skeletal muscle, liver and heart FAO. The inability to store fat may initiate a cascade of events leading to FA oversupply to lean tissue, overload of the oxidative pathway, and accumulation of toxic lipid species and triglycerides, and it was paralleled by a proportional growth in insulin resistance. In subjects with CAD, the accumulation of ectopic fat inside the pericardium is associated with impaired myocardial perfusion, presumably via a paracrine/vasocrine effect. At the beginning of the disease, TMZ is not detrimental to health; on the contrary at the single organ level (heart, skeletal muscle and liver) it seems beneficial, while no relevant effects were found on adipose tissue function. Taken altogether these findings suggest that adipose tissue storage capability should be preserved, if it is not possible to prevent excessive fat intake in the first place.

Application of Computational Fluid Dynamics in Modeling Blood Flow in Human Thoracic Aorta

The aim of this study was to simulate blood flow in thoracic human aorta and understand the role of flow dynamics in the initialization and localization of atherosclerotic plaque in human thoracic aorta. The blood flow dynamics in idealized and realistic models of human thoracic aorta were numerically simulated in three idealized and two realistic thoracic aorta models. The idealized models of thoracic aorta were reconstructed with measurements available from literature, and the realistic models of thoracic aorta were constructed by image processing Computed Tomographic (CT) images. The CT images were made available by South Karelia Central Hospital in Lappeenranta. The reconstruction of thoracic aorta consisted of operations, such as contrast adjustment, image segmentations, and 3D surface rendering. Additional design operations were performed to make the aorta model compatible for the numerical method based computer code. The image processing and design operations were performed with specialized medical image processing software. Pulsatile pressure and velocity boundary conditions were deployed as inlet boundary conditions. The blood flow was assumed homogeneous and incompressible. The blood was assumed to be a Newtonian fluid. The simulations with idealized models of thoracic aorta were carried out with Finite Element Method based computer code, while the simulations with realistic models of thoracic aorta were carried out with Finite Volume Method based computer code. Simulations were carried out for four cardiac cycles. The distribution of flow, pressure and Wall Shear Stress (WSS) observed during the fourth cardiac cycle were extensively analyzed. The aim of carrying out the simulations with idealized model was to get an estimate of flow dynamics in a realistic aorta model. The motive behind the choice of three aorta models with distinct features was to understand the dependence of flow dynamics on aorta anatomy. Highly disturbed and nonuniform distribution of velocity and WSS was observed in aortic arch, near brachiocephalic, left common artery, and left subclavian artery. On the other hand, the WSS profiles at the roots of branches show significant differences with geometry variation of aorta and branches. The comparison of instantaneous WSS profiles revealed that the model with straight branching arteries had relatively lower WSS compared to that in the aorta model with curved branches. In addition to this, significant differences were observed in the spatial and temporal profiles of WSS, flow, and pressure. The study with idealized model was extended to study blood flow in thoracic aorta under the effects of hypertension and hypotension. One of the idealized aorta models was modified along with the boundary conditions to mimic the thoracic aorta under the effects of hypertension and hypotension. The results of simulations with realistic models extracted from CT scans demonstrated more realistic flow dynamics than that in the idealized models. During systole, the velocity in ascending aorta was skewed towards the outer wall of aortic arch. The flow develops secondary flow patterns as it moves downstream towards aortic arch. Unlike idealized models, the distribution of flow was nonplanar and heavily guided by the artery anatomy. Flow cavitation was observed in the aorta model which was imaged giving longer branches. This could not be properly observed in the model with imaging containing a shorter length for aortic branches. The flow circulation was also observed in the inner wall of the aortic arch. However, during the diastole, the flow profiles were almost flat and regular due the acceleration of flow at the inlet. The flow profiles were weakly turbulent during the flow reversal. The complex flow patterns caused a non-uniform distribution of WSS. High WSS was distributed at the junction of branches and aortic arch. Low WSS was distributed at the proximal part of the junction, while intermedium WSS was distributed in the distal part of the junction. The pulsatile nature of the inflow caused oscillating WSS at the branch entry region and inner curvature of aortic arch. Based on the WSS distribution in the realistic model, one of the aorta models was altered to induce artificial atherosclerotic plaque at the branch entry region and inner curvature of aortic arch. Atherosclerotic plaque causing 50% blockage of lumen was introduced in brachiocephalic artery, common carotid artery, left subclavian artery, and aortic arch. The aim of this part of the study was first to study the effect of stenosis on flow and WSS distribution, understand the effect of shape of atherosclerotic plaque on flow and WSS distribution, and finally to investigate the effect of lumen blockage severity on flow and WSS distributions. The results revealed that the distribution of WSS is significantly affected by plaque with mere 50% stenosis. The asymmetric shape of stenosis causes higher WSS in branching arteries than in the cases with symmetric plaque. The flow dynamics within thoracic aorta models has been extensively studied and reported here. The effects of pressure and arterial anatomy on the flow dynamic were investigated. The distribution of complex flow and WSS is correlated with the localization of atherosclerosis. With the available results we can conclude that the thoracic aorta, with complex anatomy is the most vulnerable artery for the localization and development of atherosclerosis. The flow dynamics and arterial anatomy play a role in the localization of atherosclerosis. The patient specific image based models can be used to diagnose the locations in the aorta vulnerable to the development of arterial diseases such as atherosclerosis.

DENDROCLIMATOLOGICAL RECONSTRUCTION OF SPRING-SUMMER PRECIPITATION FOR FAZENDA RIO GRANDE, PR, WITH SAMPLES OF Araucaria angustifolia (Bertol.) Kuntze

ABSTRACT Samples of Araucaria angustifolia were collected at Fazenda Rio Grande, Paraná, Brazil (25°39'S 49 18'O) in January 2011. The 32 samples from 8 trees were subjected to treatments following dendrochronological techniques. The cores were measured and dated using optical and computational methodology, and then standardized to obtain a growth-ring time series, which considers the 1907-2009 time range and represents Fazenda Rio Grande. Tree-ring indices were analyzed and correlated to temperature and precipitation averages from the 1961-2009 range. This procedure aimed to study and understand the influence of the local climate on the plant growth and if this influence can be quantified. A. angustifolia trees produce visible annual growth rings, and their earlywood and latewood are clearly defined. The present study shows that A. angustifolia is sensitive to climate variables (e.g., low temperatures in wintertime tend to stop the growth rate). The correlation between tree rings and monthly precipitation series showed a common trend, making it possible to estimate the seasonal rainfall behavior for the entire 1907-2009 range.

Vulvar reconstruction should be performed using gluteal-fold perforator flap because of less morbidities and complications

The autors present a case of bilateral vulvar defects after abrasion of malignant skin neoplasm, reconstructed with a gluteal-fold perforator flap, resulting in a successful outcome.

Study of carotid disease in patients with peripheral artery disease

Objective: To study the stenosis of the carotid arteries in patients with symptomatic peripheral arterial disease.Methods: we assessed 100 consecutive patients with symptomatic peripheral arterial disease in stages of intermittent claudication, rest pain or ulceration. Carotid stenosis was studied by echo-color-doppler, and considered significant when greater than or equal to 50%. We used univariate analysis to select potential predictors of carotid stenosis, later taken to multivariate analysis.Results: The prevalence of carotid stenosis was 84%, being significant in 40% and severe in 17%. The age range was 43-89 years (mean 69.78). Regarding gender, 61% were male and 39% female. Half of the patients had claudication and half had critical ischemia. Regarding risk factors, 86% of patients had hypertension, 66% exposure to smoke, 47% diabetes, 65% dyslipidemia, 24% coronary artery disease, 16% renal failure and 60% had family history of cardiovascular disease. In seven patients, there was a history of ischemic cerebrovascular symptoms in the carotid territory. The presence of cerebrovascular symptoms was statistically significant in influencing the degree of stenosis in the carotid arteries (p = 0.02 at overall assessment and p = 0.05 in the subgroups of significant and non-significant stenoses).Conclusion: the study of the carotid arteries by duplex scan examination is of paramount importance in the evaluation of patients with symptomatic peripheral arterial disease, and should be systematically conducted in the study of such patients.

Splenic vein graft for the reconstruction of the mesenteric-portal trunk after gastroduodenopancreatectomy

Resection of the confluence of the superior mesenteric and portal veins has been performed most frequently in the treatment of adenocarcinoma of the pancreas, in view of the reported positive results, but it can also be used in cases of benign pancreatic neolpasias when they are strongly adhered to the mesenteric-portal trunk. Nevertheless, there is no study on the best type of venous grafts for reconstruction of the mesenteric-portal trunk when required. The choice of graft depends on the preference of the surgeon or the institution. This technical note critically discusses the use of the splenic vein as an option for mesenteric-portal trunk reconstruction after gastroduodenopancreatectomy.

Ureteral reconstruction with abdominal wall muscle flap: experimental study in rabbits

The authors detail the experimental development of a technique for the reconstruction of the ureter using a tubular shape, muscle flap of the abdominal wall. the preliminary results indicate the feasibility of this surgical technique.

Endovascular treatment of popliteal artery aneurysm. Early and midterm results

OBJECTIVE: to evaluate the efficacy of endovascular repair of popliteal artery aneurysms on maintaining patency of the stent in the short and medium term. METHODS: this was a retrospective, descriptive and analytical study, conducted at the Integrated Vascular Surgery Service at the Hospital da Beneficência Portuguesa de São Paulo. We followed-up 15 patients with popliteal aneurysm, totaling 18 limbs, treated with stent from May 2008 to December 2012. RESULTS: the mean follow-up was 14.8 months. During this period, 61.1% of the stents were patent. The average aneurysm diameter was 2.5cm, ranging from 1.1 to 4.5cm. The average length was 5cm, ranging from 1.5 to 10 cm. In eight cases (47.1%), the lesion crossed the joint line, and in four of these occlusion of the prosthesis occurred. In 66.7% of cases, treatment was elective and only 33.3% were symptomatic patients treated on an emergency basis. The stents used were Viabahn (Gore) in 12 cases (66.7%), Fluency (Bard) in three cases (16.7%), Multilayer (Cardiatis) in two cases (11.1%) and Hemobahn (Gore) in one case (5.6%). In three cases, there was early occlusion (16.6%). During follow-up, 88.2% of patients maintained antiplatelet therapy. There was no leakage at ultrasound (endoleak). No fracture was observed in the stents. CONCLUSION: the results of this study are similar to other published series. Probably, with the development of new devices that support the mechanical characteristics found on the thighs, there will be improved performance and prognosis of endovascular restoration.