Search results for "detector"
showing 10 items of 3491 documents
High Resolution CT Angiography in Detection of an Aneurysm of the Vein of Galen as a Source of Intracranial Haemorrhage in a Newborn.
2011
Cerebral haemorrhage is a rare condition in infants and carries a known poor prognosis. Common causes of spontaneous haemorrhage include various vascular venous lesions due to incomplete hydrovenous maturation, among them Galen vein aneurysm may be a very rare cause of cerebral haemorrhage. This report emphasizes the role of multidector CT with high resolution CT angiography in a newborn with cerebral hemorrhage caused by Galen vein aneurysm rupture. MDCT with high resolution CT angiography helps to differentiate the cause of haemorrhage, and to address the appropriate treatment.
Hepatic mesenchymal hamartoma in a preterm newborn: demonstration by low-dose multidetector CT.
2007
Primary liver tumours are very rare in the neonatal period. Differential diagnoses include haemangioendothelioma, malignant hepatoblastoma and mesenchymal hamartoma. Due to non-specific clinical symptoms and indecisive imaging findings, correct diagnosis may be difficult to establish. We report a female preterm newborn who was delivered at 33 weeks of gestation and in whom ultrasonography (US) revealed a large cystic intraabdominal tumour of unknown origin. For further evaluation, contrast-enhanced multidetector computed tomography (CT) was performed on the 4th day of life using a low-dose protocol (80 kVp, 50 mAs, collimation 0.75 mm, total effective dose 3.6 mSv). Based on CT findings, di…
Common pitfalls when using the Liver Imaging Reporting and Data System (LI-RADS): lessons learned from a multi-year experience
2018
The goal of the Liver Imaging Reporting and Data System (LI-RADS) is to standardize the interpretation and reporting of liver observations on contrast-enhanced CT and MR imaging of patients at risk for hepatocellular carcinoma. Although LI-RADS represents a significant achievement in standardization of the diagnosis and management of cirrhotic patients, complexity and caveats to the algorithm may challenge correct application in clinical practice. The purpose of this paper is to discuss common pitfalls and potential solutions when applying LI-RADS in practice. Knowledge of the most common pitfalls may improve the diagnostic confidence and performance when using the LI-RADS system for the in…
A Monte Carlo-aided design of a modular 241Am-Be neutron irradiator
2013
Monte Carlo studies aimed at designing a modular 241Am-Be neutron irradiator for testing neutron detectors and personal dosimeters and processing large volume samples are reported in this study. The evaluation of the shapes and thicknesses of the moderator and shielding materials was carried out by a MCNP5 Monte Carlo simulation code. The reliability of the simulation was experimentally verified by the activation of gold foils and TLD dosimeter measurements in an irradiation cell placed at the center of the test configuration.
Imaging of inner ear malformations: a primer for radiologists
2021
AbstractIn the multidisciplinary management of patients with inner ear malformations (IEMs), the correct diagnosis makes the differences in terms of clinical and surgical treatment. The complex anatomical landscape of the inner ear, comprising several small structures, makes imaging of this region particularly challenging for general radiologists. Imaging techniques are important for identifying the presence and defining the type of IEM and the cochlear nerve condition. High-resolution magnetic resonance imaging (MRI) sequences and high-resolution computed tomography (HRCT) are the mainstay imaging techniques in this area. Dedicated MRI and HRCT protocols play an important role in the diagn…
Tomografía computarizada multidetector en el traumatismo facial: informe estructurado y observaciones clave para un abordaje sistemático
2019
Facial fractures, often related to traffic accidents, assault, work-related accidents, or falls, account for a considerable number of emergencies in our hospitals and are associated with high morbidity and mortality. Multidetector computed tomography (MDCT) is the imaging technique of choice in this scenario because it is widely available, fast, and useful for characterizing facial fractures and associated complications, including those located in the head. For all these reasons, MDCT is fundamental in the clinical management of these patients and in planning surgery. This paper describes the radiological anatomy of the facial region, underlining the importance of the facial buttresses, and…
ECG Analysis for Ventricular Fibrillation Detection Using a Boltzmann Network
2015
Arrhythmias consist on electrical alterations in the heart beat control. They can be identified by means of surface ECG leads. The main goal of this work is to provide a signal classification based on ECG signal waveform in the time-frequency domain especially targeted to Ventricular Fibrillation detection. The use of a classifier based on a Boltzmann network is proposed. However, a previous signal preprocessing is also required so that the Boltzmann network is fed with the appropriate data. In this case, an R-wave detector is used; after that, the Pseudo Wigner-Ville time-frequency distribution is obtained. This distribution is used to train and test the network, which handles it as an ima…
CNO and pep solar neutrino measurements and perspectives in Borexino
2015
International audience; The detection of neutrinos emitted in the CNO reactions in the Sun is one of the ambitious goals of Borexino Phase-II. A measurement of CNO neutrinos would be a milestone in astrophysics, and would allow to solve serious issues in current solar models. A precise measurement of the rate of neutrinos from the pep reaction would allow to investigate neutrino oscillations in the MSW transition region. The pep and CNO solar neutrino physics, the measurement in Borexino Phase-I and the perspectives for the new phase are reviewed in this proceeding.
Measurement of Solar pp-neutrino flux with Borexino: results and implications
2015
International audience; Measurement of the Solar pp-neutrino flux completed the measurement of Solar neutrino fluxes from the pp-chain of reactions in Borexino experiment. The result is in agreement with the prediction of the Standard Solar Model and the MSW/LMA oscillation scenario. A comparison of the total neutrino flux from the Sun with Solar luminosity in photons provides a test of the stability of the Sun on the 10(5) years time scale, and sets a strong limit on the power production by the unknown energy sources in the Sun.
Improved measurement of $^8$B solar neutrinos with $1.5 kt·y$ of Borexino exposure
2017
We report on an improved measurement of the $^8$B solar neutrino interaction rate with the Borexino experiment at the Laboratori Nazionali del Gran Sasso. Neutrinos are detected via their elastic scattering on electrons in a large volume of liquid scintillator. The measured rate of scattered electrons above 3 MeV of energy is $0.223\substack{+0.015 \\ -0.016}\,(stat)\,\substack{+0.006 \\ -0.006}\,(syst)$ cpd/100 t, which corresponds to an observed solar neutrino flux assuming no neutrino flavor conversion of $\Phi\substack{\rm ES \\ ^8\rm B}=2.57\substack{+0.17 \\ -0.18}(stat)\substack{+0.07\\ -0.07}(syst)\times$10$^6$ cm$^{-2}\,$s$^{-1}$. This measurement exploits the active volume of the …