Search results for "X-Ray"
showing 10 items of 4234 documents
Update on diagnostic strategies of pulmonary embolism
1999
Acute pulmonary embolism is a frequent disease with non-specific findings, high mortality, and multiple therapeutic options. A definitive diagnosis must be established by accurate, non-invasive, easily performed, cost-effective, and widely available imaging modalities. Conventional diagnostic strategies have relied on ventilation-perfusion scintigraphy complemented by venous imaging. If the results are inconclusive, pulmonary angiography, which is regarded as the gold standard, is to be performed. Recently, marked improvements in CT and MRI and shortcomings of scintigraphy led to an update of the diagnostic strategy. Spiral CT is successfully employed as a second-line procedure to clarify i…
Computed tomography of bowel obstruction: Tricks of the trade
2015
Bowel obstruction (BO) is a frequent cause of hospitalization and surgical consultation for acute abdominal pain. It is usually suspected at physical examination, but clinical and laboratory data are often nonspecific. Thus, computed tomography plays a crucial role in a correct diagnosis of BO. Indeed, computed tomography can confirm a diagnosis of BO, and identify the location and cause of the obstruction. In this review, the computed tomography appearances of common and uncommon causes of BO and pseudo-obstruction are reviewed.
Visualizing the atherosclerotic plaque: a chemical perspective.
2014
Atherosclerosis is the major underlying pathologic cause of coronary artery disease. An early detection of the disease can prevent clinical sequellae such as angina, myocardial infarction, and stroke. The different imaging techniques employed to visualize the atherosclerotic plaque provide information of diagnostic and prognostic value. Furthermore, the use of contrast agents helps to improve signal-to-noise ratio providing better images. For nuclear imaging techniques and optical imaging these agents are absolutely necessary. We report on the different contrast agents that have been used, are used or may be used in future in animals, humans, or excised tissues for the distinct imaging moda…
A CAD system for nodule detection in low-dose lung CTs based on region growing and a new active contour model
2007
A computer-aided detection (CAD) system for the selection of lung nodules in computer tomography (CT) images is presented. The system is based on region growing (RG) algorithms and a new active contour model (ACM), implementing a local convex hull, able to draw the correct contour of the lung parenchyma and to include the pleural nodules. The CAD consists of three steps: (1) the lung parenchymal volume is segmented by means of a RG algorithm; the pleural nodules are included through the new ACM technique; (2) a RG algorithm is iteratively applied to the previously segmented volume in order to detect the candidate nodules; (3) a double-threshold cut and a neural network are applied to reduce…
Atypical radiological presentation of multiple cystic brain metastases from lung cancer simulating neurocysticercosis.
2019
Brain metastases (BMs) are usually characterised by vasogenic oedema and mass effect, but cystic appearance can rarely occur, mimicking parasitosis, such as neurocysticercosis (NCC). A woman in her mid-50s was admitted for dizziness and upper left extremity paresis. Neuroimaging showed multiple cystic lesions consistent with multiple stages of NCC evolution, and empiric albendazole was started, without any clinical improvement. A whole-body CT revealed a pulmonary lesion in the right superior lobe. Pathological analysis from brain specimen demonstrated a clear cell lung carcinoma. The patient gradually worsened and died 4 months after the diagnosis. In conclusion, multiple cystic BMs are an…
Structured Reporting of Solid and Cystic Pancreatic Lesions in CT and MRI: Consensus-Based Structured Report Templates of the German Society of Radio…
2020
Radiological reports of pancreatic lesions are currently widely formulated as free texts. However, for optimal characterization, staging and operation planning, a wide range of information is required but is sometimes not captured comprehensively. Structured reporting offers the potential for improvement in terms of completeness, reproducibility and clarity of interdisciplinary communication. Interdisciplinary consensus finding of structured report templates for solid and cystic pancreatic tumors in computed tomography (CT) and magnetic resonance imaging (MRI) with representatives of the German Society of Radiology (DRG), German Society for General and Visceral Surgery (DGAV), working grou…
Effects of obesity on periodontal tissue remodeling during orthodontic movement.
2021
Made available in DSpace on 2021-06-25T15:01:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) German Research Foundation (DFG) Introduction: Orthodontic movement triggers a sequence of cellular and molecular events that may be affected by different systemic conditions. This study evaluated the effect of obesity on rat periodontal tissue remodeling induced by mechanical orthodontic force. Methods: Thirty-two Holtzman rats were distributed into 4 groups: control, obesity induction (O), orthodontic movement (M), and obesity induction and orthodontic movement (OM). Obesity was induced by a high-fat diet for 90 days. Af…
Patent Foramen Ovale and Thromboembolic Complications
2010
The foramen ovale, an atrial septal defect which is essential in the fetal circulation, remains patent through adulthood in approximately 25% of the general population and so it represents the most common persistent abnormality of fetal origin. Patent foramen ovale (PFO) allows interatrial right-to-left blood shunting during those periods of the cardiac cycle in which the right atrial pressure exceeds the left one. An increasing number of pathological manifestations of PFO has been recently identified; among these, paradoxical systemic embolism, refractory hypoxemia in patients with right ventricular myocardium infarction or severe pulmonary disease, orthostatic oxygen desaturation in the r…
Graph-matching based CTA.
2009
Separating bone, calcification, and vessels in computer tomography angiography (CTA) allows for a detailed diagnosis of vessel stenosis. This paper presents a new, graph-based technique that solves this difficult problem with high accuracy. The approach requires one native data set and one that is contrast enhanced. On each data set, an attributed level-graph is derived and both graphs are matched by dynamic programming to differentiate between bone, on one hand side, and vessel/calcification on the other hand side. Lumen and calcified regions are then separated by a profile technique. Evaluation is based on data from vessels of pelvis and lower extremities of elderly patients. Due to subst…
Bond strength of cemented fiber posts to teeth with simulated internal root resorption
2020
Made available in DSpace on 2021-06-25T10:58:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Background: Teeth with internal root resorption (IRR) have guarded prognosis, considering that IRR defect could influence on the post bond strength. The aim of this study was to evaluate the bond strength and the bond interface between different glass fiber-reinforced posts (FRP) after cementation in teeth with simulated internal root resorption (IRR). Material and Methods: Forty-five (45) human premolar roots with simulated IRR were embedded in acrylic resin blocks and cross-sectioned into two segments, enabling them to be re-approximated by screws. Intracanal medication was inserte…