Search results for "algorithm."

A leptin missense mutation associated with hypogonadism and morbid obesity

1998

Evidence-based medicine and the problem of healthy volunteers

2017

Abstract Healthy controls are subjects without the disease being studied but may have other conditions indirectly affecting outcome. In the present epidemics of obesity a few subjects with undiagnosed nonalcoholic fatty liver disease enter clinical studies as controls, producing biased results. Stricter selection criteria should be considered to prevent this risk.

Automatic detection of lung nodules in CT datasets based on stable 3D mass–spring models

2012

We propose a computer-aided detection (CAD) system which can detect small-sized (from 3 mm) pulmonary nodules in spiral CT scans. A pulmonary nodule is a small lesion in the lungs, round-shaped (parenchymal nodule) or worm-shaped (juxtapleural nodule). Both kinds of lesions have a radio-density greater than lung parenchyma, thus appearing white on the images. Lung nodules might indicate a lung cancer and their early stage detection arguably improves the patient survival rate. CT is considered to be the most accurate imaging modality for nodule detection. However, the large amount of data per examination makes the full analysis difficult, leading to omission of nodules by the radiologist. We…

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…

Magnetic resonance cholangiopancreatography

2002

With the introduction of endoscopic retrograde cholangio-pancreatography in the early 1970s, gastroenterologists have a lot of diagnostic options in the biliopancreatic system to their disposal. Meanwhile, magnetic resonance cholangiopancreatography (MRCP) has become a competitive replacement for diagnostic ERCP with the advantage of avoiding complications related to endoscopic techniques. Mounting evidence suggests that both MRCP and MRI (magnetic resonance imaging) have a profound influence of diagnostic algorithms in a variety of hepatobiliary and pancreatic diseases.

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…

Prediction of dilutional acidosis based on the revised classical dilution concept for bicarbonate

2004

Due to the controversy surrounding the term dilutional acidosis, the classical dilution concept for bicarbonate has been rigorously revised for the prediction of pH, actual bicarbonate concentration, and base excess. In the algorithms derived for buffer solutions, blood, and whole body (1-, 2-, and 3-fluid compartment), only bicarbonate is considered. On dilution at constant Pco2, the final concentration of bicarbonate is the sum in terms of pH, due to the following processes: dilution, formation from chemical reaction with the nonbicarbonate buffers phosphate, hemoglobin, and plasma proteins, and transfer from erythrocytes and interstitial fluid to plasma. At constant Pco2, the level of c…

Verification of a commercial implementation of the Macro-Monte-Carlo electron dose calculation algorithm using the virtual accelerator approach.

2009

Abstract In this work, the accuracy of the implementation of the Macro Monte Carlo electron dose calculation algorithm into the radiation therapy treatment planning system Eclipse is evaluated. This implementation – called eMC – uses a particle source based on the Rotterdam Initial Phase-Space model. A three-dimensional comparison of eMC calculated dose to dose distributions resulting from full treatment head simulations with the Monte Carlo code package EGSnrc is performed using the ‘virtual accelerator’ approach. Calculated dose distributions are compared for a homogeneous tissue equivalent phantom and a water phantom with air and bone inhomogeneities. The performance of the eMC algorithm…

Mobilization of short-term memory capacity for odors in discriminative tests: implication for assessors' selection

2004

Abstract The objective was to determine whether individual short-term memory capacities for odor are related to performance at discriminative tests. Two groups of 11 subjects were formed with different short-term memory for odor but equivalent sensitivity toward benzaldehyde, the aromatic compound to be detected in discriminative tests. The subject sensitivity was determined by d ′ values, derived from a detection task. Memory span for odors was the largest number of odors memorized at once. It ranged from 1 to 3 for the low memory span group and from 5 to 7 for the high memory span group. Then, subjects performed 20 triangle tests and 12 2-out-of-5 tests with two strawberry flavored soft d…

A novel heuristic algorithm for the modeling and risk assessment of the COVID-19 pandemic phenomenon

2020

This article belongs to the special issue: Soft computing techniques in materials science and engineering Summarization: The modeling and risk assessment of a pandemic phenomenon such as COVID-19 is an important and complicated issue in epidemiology, and such an attempt is of great interest for public health decision-making. To this end, in the present study, based on a recent heuristic algorithm proposed by the authors, the time evolution of COVID-19 is investigated for six different countries/states, namely New York, California, USA, Iran, Sweden and UK. The number of COVID-19-related deaths is used to develop the proposed heuristic model as it is believed that the predicted number of dai…