Aneurisma de arteria carótida interna. Caso clínico

Introducción: Los aneurismas de la arteria carótida extracraneal (ACEC) son poco frecuentes en comparación con las lesiones oclusivas. Los ACEC son menos del 1% de todos los aneurismas arteriales y solo el 10% son considerados aneurismas verdaderos. Caso Clínico: Paciente femenina de 84 años, en excelentes condiciones generales, hipertensa e hiperlipidémica, neurológicamente asintomática, con hallazgo de aneurisma de carótida interna derecha en el contexto de una arteria elongada, estenosis moderada ostial y oclusión de arteria carótida interna contralateral. Se realiza resección de aneurisma con anastomosis término terminal, endarterectomía del ostium y angioplastía con parche. Su evolución fue favorable, manteniéndose asintomática y con la reconstrucción permeable a 6 meses de seguimiento en eco duplex. Discusión: La elección del manejo del ACEC va a depender de sus características morfológicas, en este caso la presencia de tortuosidad extrema de la arteria carótida interna dificultaba la posibilidad de manejo endovascular, pero facilitaba la resección del aneurisma con anastomosis primaria término terminal. Conclusión: La aneurismectomía y reconstrucción es una modalidad de manejo disponible para los ACEC.

Introduction: Extracranial carotid artery aneurysms (ECAA) are rare compared to occlusive disease, less than 1% of all arterial aneurysms and only 10% are considered true aneurysms. Clinical case: A 84-year-old female, active and in excellent general health, with a prior history significant only for hypertension and hyperlipidemia was referred for a right internal carotid artery aneurysm and elongation in the context of contralateral internal carotid artery occlusion. The patient denied neurologic symptoms. Resection of the aneurysm and end-to-end anastomosis, endarterectomy of the ostium and patch angioplasty was performed. The patient had an uneventful recovery, remaining asymptomatic and the reconstruction patent on duplex scan at 6 month follow up. Discussion: The choice of repair alternatives for EICA depend on its morphological characteristics. The presence of extreme tortuosity of the internal carotid artery in this case, on one hand make difficult to consider endovascular alternatives, but facilitates aneurysm resection and primary end-to-end anastomosis. Conclusion: Aneurysmectomy and arterial reconstruction is a treatment alternative for EICA repair.

Ocular involvement in primary antiphospholipid syndrome: results of an extensive ophthalmological evaluation performed in the APS-Rio cohort.

OBJECTIVE: To study ophthalmological manifestations in a well-characterized primary antiphospholipid syndrome (PAPS) cohort (APS-Rio) and compare them with a healthy control group. METHODS: We examined PAPS patients and controls with an extensive ophthalmological evaluation, which included anamnesis, visual acuity, slit-lamp biomicroscopy, binocular indirect ophthalmoscopy, and retinography of the anterior and posterior segments of the eye. PAPS group also underwent angiography exam and optical coherence tomography using spectral domain technology (SD-OCT). RESULTS: 98 PAPS patients and 102 controls were included. The most common symptom in PAPS was amaurosis fugax (34.7% vs. 6.9%; p = .001). In the multivariate analyses, Raynaud's phenomenon was associated with amaurosis fugax (OR 3.71, CI:1.33-10.32; p = .012), and livedo correlated with hemianopia (OR 6.96, CI:1.11-43.72, p = .038) and diplopia (OR 3.49, CI:1.02-11.53, p = .047). After ophthalmological evaluation, 84 PAPS patients had ocular involvement (1.0% glaucoma, 94.0% posterior findings, 62.7% anterior findings, and 56.6% both posterior and anterior findings). Vascular tortuosity was more frequent in the PAPS group (63.2% vs. 42.2%; p = .002), as well as peripheral tortuosity (29.6% vs. 7.8%; p < .001). After excluding patients with atherosclerotic risk factors, peripheral vascular tortuosity was still statistically associated with PAPS (35.0 vs. 7.8%, p < .001). Triple positivity was more frequent in PAPS patients with peripheral vascular tortuosity than in those without this ocular finding (34.5% vs. 15.9%, p = .041). CONCLUSION: Vasomotor phenomena are importantly related to ocular symptoms in PAPS. Vascular tortuosity was a frequent finding in PAPS patients. Peripheral vascular tortuosity was associated with triple positivity and might be a biomarker of ischemic microvascular retinopathy due to PAPS.

An analysis of the influence of transfer learning when measuring the tortuosity of blood vessels.

BACKGROUND AND OBJECTIVE: Convolutional Neural Networks (CNNs) can provide excellent results regarding the segmentation of blood vessels. One important aspect of CNNs is that they can be trained on large amounts of data and then be made available, for instance, in image processing software. The pre-trained CNNs can then be easily applied in downstream blood vessel characterization tasks, such as the calculation of the length, tortuosity, or caliber of the blood vessels. Yet, it is still unclear if pre-trained CNNs can provide robust, unbiased, results in downstream tasks involving the morphological analysis of blood vessels. Here, we focus on measuring the tortuosity of blood vessels and investigate to which extent CNNs may provide biased tortuosity values even after fine-tuning the network to a new dataset under study. METHODS: We develop a procedure for quantifying the influence of CNN pre-training in downstream analyses involving the measurement of morphological properties of blood vessels. Using the methodology, we compare the performance of CNNs that were trained on images containing blood vessels having high tortuosity with CNNs that were trained on blood vessels with low tortuosity and fine-tuned on blood vessels with high tortuosity. The opposite situation is also investigated. RESULTS: We show that the tortuosity values obtained by a CNN trained from scratch on a dataset may not agree with those obtained by a fine-tuned network that was pre-trained on a dataset having different tortuosity statistics. In addition, we show that improving the segmentation accuracy does not necessarily lead to better tortuosity estimation. To mitigate the aforementioned issues, we propose the application of data augmentation techniques even in situations where they do not improve segmentation performance. For instance, we found that the application of elastic transformations was enough to prevent an underestimation of 8% of blood vessel tortuosity when applying CNNs to different datasets. CONCLUSIONS: The results highlight the importance of developing new methodologies for training CNNs with the specific goal of reducing the error of morphological measurements, as opposed to the traditional approach of using segmentation accuracy as a proxy metric for performance evaluation.

Retinal vascular tortuosity: Mechanisms and measurements.

Retinal vessel tortuosity has been used in the diagnosis and management of different clinical situations. Notwithstanding, basic concepts, standards and tools of measurement, reliable normative data and clinical applications have many gaps or points of divergence. In this review we discuss triggering causes of retinal vessel tortuosity and resources used to assess and quantify it, as well as current limitations.

Tortuous ulnar artery presenting as left distal forearm mass.

Knowledge of anatomic variation in vasculature is critical to safe medical intervention as conduits vary in morphology, architecture, and course. Tortuosity is a common anatomic variant in certain arterial beds; however, its prevalence in ulnar arteries is not well documented in the literature. Here we report two cases of tortuous ulnar arteries in patients being evaluated for upper extremity hemodialysis access.

Splenic artery tortuosity index on abdominal CT Scan: correlation with age, sex, BMI and abdominal cavity diameters / Índice de tortuosidad de la arteria esplénica en TC abdominal: correlación con la edad, el sexo, el IMC y los diámetros de la cavidad abdominal

Thorough knowledge of splenic artery course and morphology may help clinician to provide better practice. This Study aims at finding out if there was a relationship between splenic artery tortuosity index and age, sex, Body Mass Index (BMI) and abdominal cavity diameters. Routine abdominal Computerized Tomography (CT) scan images were retrospectively analyzed for 219 patients. Splenic artery tortuosity index was calculated. Abdominal cavity diameters were measured. Age, sex, and BMI were recorded. Splenic artery straight length (x) mean was 9.41 cm (SD 1.33). Splenic artery tortuous length mean was 15.15 cm (SD 3.31). Splenic artery tortuosity index mean was 1.63 (SD 0.36). Pearson correlation coefficient for Splenic artery tortuosity index vs. age was: 0.02 (P value 0.80). Splenic artery tortuosity index for females vs. males were 1.70 vs. 1.57 (P value 0.01). Pearson correlation coefficient for Splenic artery tortuosity index vs. BMI was 0.02 (P value 0.75). Pearson correlation coefficient for Splenic artery tortuosity index vs. abdominal cavity diameters were: Anterior-Posterior (AP) diameter -0.01 (P value 0.88) and transverse diameter 0.00 (P value 0.98). There may be a relationship between splenic artery tortuosity and female sex, but not with age, BMI and abdominal cavity diameters (AP and Transverse).

El conocimiento del curso y la morfología de la arteria esplénica puede ayudar al médico a proporcionar un diagnóstico y tratamiento oportuno al paciente. Este estudio tuvo como objetivo determinar si existe una relación entre el índice de tortuosidad de la arteria esplénica y la edad, el sexo, el índice de masa corporal (IMC) y los diámetros de la cavidad abdominal. Se tomaron imágenes retrospectivas, de rutina, de 219 pacientes de tomografía computarizada (TC) abdominal. Se calculó el índice de tortuosidad de la arteria esplénica. Se midieron los diámetros de la cavidad abdominal y se registró la edad, sexo y el IMC. La media de la longitud recta de la arteria esplénica (x) fue de 9,41 cm (DE 1,33). La longitud tortuosa de la arteria esplénica fue de 15,15 cm (DE 3,31). La media del índice de tortuosidad de la arteria esplénica fue de 1,63 (DE 0,36). El coeficiente de correlación de Pearson para el índice de tortuosidad de la arteria esplénica vs. edad fue: 0,02 (valor de P 0,80). El índice de tortuosidad de la arteria esplénica para las mujeres frente a los hombres fue de 1,70 frente a 1,57 (valor de P 0,01). El coeficiente de correlación de Pearson para el índice de tortuosidad de la arteria esplénica versus el IMC fue de 0,02 (valor de P 0,75). El coeficiente de correlación de Pearson para el índice de tortuosidad de la arteria esplénica frente a los diámetros de la cavidad abdominal fue: diámetro anterior-posterior (AP) -0,01 (valor P 0,88) y diámetro transversal 0,00 (valor P 0,98). Puede existir una relación entre la tortuosidad de la arteria esplénica y el sexo femenino, sin embargo no se encontró relación con la edad, el IMC y los diámetros de la cavidad abdominal (AP y transversal).

Computational simulation data using the Lattice Boltzmann method to generate correlations for gas diffusion layer parameters.

Analyzing the fluid behavior in complex porous media like gas diffusion layers (GDLs) in polymer electrolyte fuel cells (PEFCs) can be accurately done using the lattice Boltzmann method (LBM). This article shows the data obtained from a study in which diffusion parameters such as porosity, gas phase tortuosity and diffusibility are computed considering simulated porous media [1]. The data were computed when a water drop obstacle is placed inside the GDL domain and the size of the water-drop is varied. Additionally, figures showing the evolution of the flow velocity field are presented alongside graphics that presents the change in local and bulk porosity for each obstacle size. Finally, there is a detailed method explanation concerning the implementation of the lattice Boltzmann method and a general description of computational codes for the domain and obstacle generation as well as the boundary conditions simulation. Data and processes in this article can be exploited in new attempts to solve real case problems in complex mesoscale media.

Assessing the long-term effects of zero-tillage on the macroporosity of Brazilian soils using X-ray Computed Tomography.

Zero-tillage (ZT) is being increasingly adopted globally as a conservationist management system due to the environmental and agronomic benefits it provides. However, there remains little information on the tillage effect on soil pore characteristics such as shape, size and distribution, which in turn affect soil physical, chemical and biological processes. X-ray micro Computed Tomography (µCT) facilitates a non-destructive method to assess soil structural properties in three-dimensions. We used X-ray µCT at a resolution of 70 µm to assess and calculate the shape, size and connectivity of the pore network in undisturbed soil samples collected from a long-term experiment (~30 years) under zero tillage (ZT) and conventional tillage (CT) systems in Botucatu, Southeastern Brazil. In both systems, a single, large pore (>1000 mm3) typically contributed to a large proportion of macroporosity, 91% in CT and 97% in ZT. Macroporosity was higher in ZT (19.7%) compared to CT (14.3%). However the average number of pores was almost twice in CT than ZT. The largest contribution in both treatments was from very complex shaped pores, followed by triaxial and acircular shaped. Pore connectivity analysis indicated that the soil under ZT was more connected that the soil under CT. Soil under CT had larger values of tortuosity than ZT in line with the connectivity results. The results from this study indicate that long-term adoption of ZT leads to higher macroporosity and connectivity of pores which is likely to have positive implications for nutrient cycling, root growth, soil gas fluxes and water dynamics.

Histological verification of atherosclerosis due to bends and bifurcations in carotid arteries predicted by hemodynamic model.

BACKGROUND: Tortuosity and bifurcations in carotid arteries alter the blood flow, causing atherosclerosis. OBJECTIVES: The aim of the present study is to analyze the effect of variant vascular anatomy in the cervical region on development of atherosclerosis by microanatomical examination. METHODS: The effect of blood flow at anomalous bends and bifurcations was observed in right carotid arteries of a seventy year old female cadaver. Fifteen histological slides were prepared from the carotid arteries and interpreted to verify predictions of atherosclerosis. RESULTS: The model predicts atherosclerosis at bends, bifurcations and large aperture arteries. Microanatomical examination revealed presence of atherosclerosis of varying thickness at the bends and bifurcation in the right carotid arteries, as predicted. Atherosclerosis was also detected in the straight part of the wider common carotid artery. No atherosclerosis was observed in the contralateral carotid arteries. The variant carotid vascular anatomy consisting of bends, bifurcations and wider arteries revealed that the shear stress and velocity of blood flow are reduced at these anomalous sites. CONCLUSIONS: Anatomical anomalies such as bends and branching in the carotid arteries alter the irrigation pattern and generate biomechanical forces that cause turbulent flow and reduce shear stress/blood flow velocity. Decreased shear stress and velocity causes development of atherosclerosis. Histological slides established the presence of atherosclerosis at bends and bifurcations and in wider arteries.

CONTEXTO: Tortuosidade e bifurcações das artérias carótidas alteram o fluxo sanguíneo, causando aterosclerose. OBJETIVOS: O objetivo do presente estudo foi analisar o efeito de anatomia vascular variante na região cervical sobre o desenvolvimento de aterosclerose via exame microanatômico. MÉTODOS: O efeito do fluxo sanguíneo em dobras e bifurcações anômalas foi observado nas artérias carótidas do lado direito em um cadáver do sexo feminino de 70 anos de idade. Quinze lâminas histológicas foram preparadas a partir das artérias carótidas e interpretadas para confirmar as previsões de aterosclerose. RESULTADOS: O modelo prevê aterosclerose em dobras, bifurcações e artérias de grande calibre. O exame microanatômico revelou a presença de aterosclerose de densidades variáveis nas dobras e bifurcação das artérias carótidas do lado direito, conforme previsto. Aterosclerose também foi detectada na parte reta da artéria carótida comum mais larga. Não foi observada aterosclerose nas artérias carótidas contralaterais. A anatomia vascular carotídea variante consistindo de dobras, bifurcações e artérias mais largas revelou que a tensão de cisalhamento (shear stress) e a velocidade do fluxo sanguíneo são reduzidos nesses pontos anômalos. CONCLUSÕES: Anomalias anatômicas tais como dobras e ramificações das artérias carótidas alteram o padrão de irrigação e geram forças biomecânicas que causam fluxo turbulento e reduzem a tensão de cisalhamento e a velocidade do fluxo. Tensão e velocidade menores causam o desenvolvimento de aterosclerose. As lâminas histológicas estabeleceram a presença de aterosclerose nas dobras e bifurcações nas artérias mais largas.

Tortuosidad discreta como medida morfométrica en tumores cerebrales / Discrete tortuosity as a morphometric measure in brain tumors

Resumen: Los tumores cerebrales pueden presentar cambios morfológicos dependiendo de su grado de malignidad. El objetivo de este trabajo es poder detectar y cuantificar estos cambios morfológicos a partir imágenes de resonancia magnética, ya que puede representar una ventaja importante para el diagnóstico no invasivo de los pacientes. Una forma de identificar dichos cambios morfológicos es a través de la medición de su tortuosidad. La tortuosidad discreta es un descriptor que caracteriza curvas bidimensionales, como el contorno de una región. En este trabajo se propone una variante para calcular la tortuosidad de superficies volumétricas. Esta técnica se basa en el uso del código cadena de cambios de pendientes del contorno superficial de un volumen y la denominamos como tortuosidad discreta tridimensional. Este descriptor se utiliza como un índice morfométrico para estudiar la tortuosidad de tumores cerebrales. Para ello se analizan imágenes de resonancia magnética de 20 pacientes con presencia de gliomas de bajo y alto grado de malignidad, considerando cuatro regiones de interés: edema, tumor entero, región activa y necrosis. Como resultado, se muestran los distintos grados de tortuosidad de las diversas regiones, encontrándose solo en algunas de ellas diferencias significativas. Cabe señalar que una desventaja que se tiene presente, es la dependencia de la medición a la utilización de un método robusto de segmentación de las regiones, sin embargo la propuesta de la tortuosidad discreta para superficies volumétricas es satisfactoria.

Abstract: A decision tree based system with heuristic weight factors oriented to diagnosis by Morphological changes in brain tumors may be related to their malignancy. The objective of this work is to be able to detect and quantify these changes in a magnetic resonance imaging, since it can represent an important advantage for the noninvasive diagnosis in patients. One way to identify such morphological changes can be through the measurement of their tortuosity. The discrete tortuosity is a descriptor that characterizes bi-dimensional curves, as the contour of a region. In this work an alternative procedure for calculating the volumetric tortuosity of a surface is proposed. This technique is based in the slope chain code of the surface contour of a volume, and here we call it tridimensional discrete tortuosity. This descriptor is used as a morphometric index to study the tortuosity of brain tumors. For this, magnetic resonance images from 20 patients with low and high malignancy levels were analyzed, considering four regions: edema, whole tumor, enhancing region, and necrotic region. As a result, the tortuosities of the different regions are presented, with significant differences only in some of them. It should be noted that a disadvantage that is present, is the dependence of the measurement to the use of a robust method of segmentation, nevertheless the proposal of the discrete tortuosity for volumetric surfaces is satisfactory.

Aneurysm, tortuosity and kinking of abdominal aorta and iliac arteries in Thai cadavers / Aneurisma, tortousidad y torsión de la parte abdominal de la aorta y de las arterias ilíacas en cadáveres tailandeses

The prevalence of the aneurysm, tortuosity, and kinking of abdominal aorta and iliac arteries is important for primary consideration in operative planning. The present study was undertaken to investigate the prevalence of abnormality of abdominal aorta and iliac arteries and demonstrate the patterns of kinking external iliac arteries in Thai cadavers. Eighty-five Thai embalmed cadavers (58 males and 27 females) were observed and measured the diameter of abdominal aorta and iliac arteries using a vernier caliper for assessment of aortic aneurysm (AAA). To investigate the tortuosity and kinking of iliac arteries, a standard goniometer was applied to measure the individual angle of iliac artery. In addition, the kinking patterns of external iliac artery were classified. The prevalence of AAA was 4.71% and the aneurysms of common and internal iliac arteries were 4.12 and 0.59%. The tortuosity of common and external iliac arteries were 1.76 and 20%. No tortuosity of internal iliac artery was observed. In addition, the kinking of common, external, and internal iliac arteries were 4.71, 16.47, and 1.18%, respectively. Moreover, the patterns of external iliac aortic kinking were classified into 4 major types (S-shape; reversed ­C shape; low grade shape; and V-shape). We have observed the prevalence of the aneurysm, tortuosity, and kinking of abdominal aorta and iliac arteries in Thai cadavers. Currently, the 4 kinking variations of external iliac arteries were also first demonstrated.

La prevalencia de aneurisma, tortuosidad y torsión de la parte abdominal de la aorta y arterias ilíacas es relevante para la consideración primaria en la planificación quirúrgica. Se realizó un estudio para investigar la prevalencia de alteraciones en las parte abdominal de la aorta y arterias ilíacas y demostrar los patrones de torsión en las arterias ilíacas externas de cadáveres tailandeses. Se observaron 85 cadáveres tailandeses embalsamados (58 hombres y 27 mujeres); se midió el diámetro de la parte abdominal de la aorta y arterias ilíacas utilizando un pie de metro para la evaluación de aneurisma aórtico. Para investigar la tortuosidad y torsión de las arterias ilíacas, se utilizó un goniómetro estándar para medir el ángulo individual de la arteria ilíaca. Además, se clasificaron los patrones de torsión de las arterias ilíacas externas. La prevalencia de aneurisma aórtico fue 4,71% y los aneurismas de las arterias ilíacas comunes e internas fueron 4,12% y 0,59%. La tortuosidad de las arterias ilíacas comunes y externas fueron 1,76% y 20%. No se observó tortuosidad de la arteria ilíaca interna. Además, la torsión de las arterias ilíacas comunes, externas e internas fueron 4,71%, 16,47% y 1,18%, respectivamente. Por otra parte, los patrones de torsión fueron clasificados en 4 tipos principales (formas de S, de C invertida; de bajo grado y en V). Observamos la presencia de aneurisma, tortuosidad y torsión de la parte abdominal de la aorta y arterias ilíacas en cadáveres tailandeses. Demostramos también por primera vez, las 4 variaciones de torsión de las arterias ilíacas externas.

Síndrome de Bonnet-Wybur-Mason: dos polos de un espectro / The Bonnet-Wyburn-Mason syndrome: two poles of one spectrum

Se comunican los casos de dos pacientes con síndrome de Bonnet, Wyburn-Mason en quienes existía un aneurisma cirsoide de la retina de diferente grado de desarrollo. En uno, el cuadro oftalmoscópico era obvio; en tanto que en el otro la manisfestación fundamental era una tortuosidad vascular acentuada y en quien solo la angiografía fluoresceínica del fondo ocular mostró sutiles cambios compatibles con una malformación arteriovenosa localizada. Otro elemento inusual en el comportamiento de este tipo de malformaciones fue la asociación a una coartación de la aorta torácica y multiples anomalías esqueléticas sencillas, así como la obstrucción de un segmento muy desarrollado de la malformación arteriovenosa con infarto hemorrágico retiniano e involución posterior de parte de ella

We communicate the cases of two patients with syndrome of Bonnet, Wyburn-Mason who had cirsoide aneurysms of the retina of differnt degrees of development. In one, the ophthalmoscopic picture was obvious, while on the other, The primary manifestation was a marked vascular tortuosity and in which only the ocular fundus fluorescein angiography showed subtle changes consistent with a located arteriovenous malformation. Another unusual element in the behavior of this type of malformations was a coarctation of the thoracic aorta and multiple skeletal anomalies simple associated, as well as the obstruction of a highly developed portion of the retinal arteriovenous malformation with hemorrhagic infarction and consecutive involution of part of it

Informe clínico de dismorfias múltiples con agregación familiar / Clinical report on multiple dysmorphias with familial aggregation

Se comunican las características clínicas de una mujer de 68 años de edad y sus dos hijas (36 y 33 años) que presentaban un conjunto de anomalías de probable origen hereditario. Se les efectuaron interconsultas con varias especialidades: medicina interna, genética, cardiología, radiología, angiología, psiquiatría, dermatología, otorrinolaringología, máxilo-facial, oftalmología y neurología. Los hallazgos comunes a las tres pacientes consistieron en tortuosidad de los vasos retinianos, glaucoma crónico de ángulo abierto, braquidactilias y otros dismorfismos en dedos de manos y pies, hallux valgus, telangiectasias en mejillas y tórax superior, orejas en ®asa», hiperostosis frontal, tórax excavado e insuficiencia mitral. El glaucoma neovascular se presentó en un ojo de cada hija. Este complejo padecimiento clínico, con alteraciones en miembros, faciales, cardiovasculares, oculares y en piel con una posible herencia de tipo autosómico dominante por su presencia en dos generaciones sucesivas, no se corresponde con ningún síndrome de los considerados en este informe

Presentation of the clinical characteristics of a 68-year-old woman and her two daughters, aged 36 and 33, who had a number of abnormalities of probable hereditary origin. Interconsultations were conducted with several specialties: internal medicine, genetics, cardiology, radiology, angiology, psychiatry, dermatology, otorhinolaryngology, maxillofacial, ophthalmology and neurology. The findings common to the three patients were retinal arterial tortuosity, chronic open angle glaucoma, brachydactyly and other dysmorphic disorders of fingers and toes, hallux valgus, telangiectasia in cheeks and upper thorax, protruding ears, frontal hyperostosis, pectus excavatum and mitral insufficiency. Both daughters had neovascular glaucoma in one of their eyes. This complex clinical condition, with disorders involving limbs, face, the cardiovascular system, eyes and skin, and a potential autosomal dominant inheritance in view of its presence in two successive generations, does not correspond to any of the syndromes considered in this report

Tortuosidade e conectividade da rede trabecular do rádio distal a partir de imagens microtomográficas / Trabecular network tortuosity and connectivity of distal radius from microtomographic images

A osteoporose é uma doença que causa perda de massa óssea e deterioração da estrutura trabecular. A rede formada pelo osso trabecular é muito importante para estabelecer a competência mecânica do esqueleto. Estudos mostram que a microarquitetura trabecular pode elevar a predição do risco de fratura para cerca de 90 por cento , por isso a sua investigação é de grande interesse da comunidade científica. Vários parâmetros estão relacionados à competência mecânica da estrutura óssea, entretanto, a tortuosidade trabecular ainda não foi seriamente levada em consideração e sua contribuição é desconhecida. Neste trabalho, o enfoque está direcionado à estimativa da tortuosidade trabecular e sua correlação com a conectividade, através da característica de Euler-Poincaré, para amostras do osso rádio distal in  vitro, a partir de imagens de microtomografia computadorizada. Um método para estimar a tortuosidade do volume trabecular é apresentado e a tortuosidade é computada para os dois sentidos das três direções do volume. Os resultados apresentam valores distintos da tortuosidade dependendo da qualidade da rede trabecular e uma correlação positiva (r  =   0,64) com a característica de Euler-Poincaré; além disso, observa-se que a tortuosidade busca alinhar-se nas direções de maiores tensões e compressões imprimidas à rede trabecular. Tais resultados evidenciam a importância da tortuosidade como parâmetro estrutural da rede trabecular.

Osteoporosis is disease causing bone mass loss and deterioration of the trabecular structure. The trabecular network is very important to establish the mechanical competence of the skeleton. It is known that the trabecular microarchitecture can improve the fracture risk prediction up to 90 percent , for this reason the trabecular bone investigation has become of great interest for the scientific community. Several parameters provide structural details of the bone mechanical competence, however, the trabecular network tortuosity has not been seriously taken into account yet and its contribution is unknown. This paper directs attention to the trabecular tortuosity estimation and its correlation to the connectivity, through Euler-Poincaré characteristic, from in  vitro distal radius bone samples by micro-computed tomographic images. A method to estimate the trabecular bone tortuosity is presented and its value is computed for both directions of the three volume axis. The results indicate that the trabecular tortuosity depends on the trabecular network quality and a positive correlation (r  = 0.64) with the Euler-Poincaré characteristic. Inasmuch, it has been observed that the tortuosity tends to get aligned in the direction of main stress imposed on trabecular bone network. These results support the tortuosity as an important structural parameter.

Abordagem metodológica baseada em imagens do SAR-R99B para identificar prováveis pistas de pouso não-homologadas na Amazônia

This study presents a methodological approach based on radar images and on gray level, size and geometric pattern to identify potential unofficial airplane strips in Amazonia. The following procedures were conducted: georeferencing of a L-band, HH polarization, 3-meter spatial resolution image obtained by the SAR-R99B system over the Itaituba municipality, State of Para; subtraction of speckle noise with a median filter; image classification with the ISODATA unsupervised technique; conversion of selected targets of interest into vector format; and calculation and automatic selection of targets of interest by the circularity and tortuosity indices. Among the 10 previously identified targets, two were considered as potential unofficial airplane strips by the above mentioned indices.

Este estudo apresenta uma abordagem metodológica baseada em imagens de radar e nos critérios de tonalidade, tamanho e forma geométrica para identificar prováveis pistas de pouso não-homologadas na Amazônia. Os seguintes procedimentos foram conduzidos: georreferenciamento da imagem do sensor SAR-R99B do município paraense de Itaituba, adquirida na banda L, polarização HH e resolução espacial de três metros; subtração do ruído speckle com filtro mediana; classificação com a técnica não-supervisionada ISODATA; vetorização da classe indicativa dos alvos de interesse; e cálculo e seleção automática dos alvos de interesse por critérios de índice de circularidade e de tortuosidade. Foram identificados dez alvos, dos quais dois foram considerados como prováveis pistas de pouso pelos referidos índices.

Abordagem metodológica baseada em imagens do SAR-R99B para identificar prováveis pistas de pouso não-homologadas na Amazônia

This study presents a methodological approach based on radar images and on gray level, size and geometric pattern to identify potential unofficial airplane strips in Amazonia. The following procedures were conducted: georeferencing of a L-band, HH polarization, 3-meter spatial resolution image obtained by the SAR-R99B system over the Itaituba municipality, State of Para; subtraction of speckle noise with a median filter; image classification with the ISODATA unsupervised technique; conversion of selected targets of interest into vector format; and calculation and automatic selection of targets of interest by the circularity and tortuosity indices. Among the 10 previously identified targets, two were considered as potential unofficial airplane strips by the above mentioned indices.

Este estudo apresenta uma abordagem metodológica baseada em imagens de radar e nos critérios de tonalidade, tamanho e forma geométrica para identificar prováveis pistas de pouso não-homologadas na Amazônia. Os seguintes procedimentos foram conduzidos: georreferenciamento da imagem do sensor SAR-R99B do município paraense de Itaituba, adquirida na banda L, polarização HH e resolução espacial de três metros; subtração do ruído speckle com filtro mediana; classificação com a técnica não-supervisionada ISODATA; vetorização da classe indicativa dos alvos de interesse; e cálculo e seleção automática dos alvos de interesse por critérios de índice de circularidade e de tortuosidade. Foram identificados dez alvos, dos quais dois foram considerados como prováveis pistas de pouso pelos referidos índices.