Search results for "Artifact"
showing 10 items of 193 documents
Undetected Malignancies of the Breast: Dynamic Contrast-enhanced MR Imaging at 1.0 T
2002
To assess the prevalence and characteristics of malignant breast lesions not identified with magnetic resonance (MR) imaging.Breast tissue specimens were obtained in 464 of 967 patients who had undergone dynamic gadolinium-enhanced T1-weighted fast low-angle shot three-dimensional MR imaging of both breasts. A comparison of sensitivity, specificity, and predictive values of the prospectively recorded findings of mammography, ultrasonography (US), and MR imaging with the histopathologic results was performed with receiver operating characteristic (ROC) curve analysis. MR imaging examination findings that caused a false-negative diagnosis were reviewed to identify possible sources of error.Hi…
Pitfalls in whole body MRI with diffusion weighted imaging performed on patients with lymphoma: What radiologists should know
2016
The technological advances in radiological imaging and the relevance of a diagnostic tool that may reduce radiation-induced long-term effects have led to a widespread use of whole body magnetic resonance imaging (WB-MRI) with diffusion weighted imaging for oncologic patients. A lot of studies demonstrated the feasibility and reliability of WB-MRI as an alternative technique for lymphoma staging and response assessment during and after treatment. In this paper, taking advantage of our 2years of experience using WB-MRI for lymphoma, we discuss the main pitfalls and artifacts radiologists should know examining a WB-MRI performed on this typology of patients in order to avoid images misinterpre…
Implant-specific follow-up imaging of treated intracranial aneurysms: TOF-MRA vs. metal artifact reduced intravenous flat panel computed tomography a…
2017
Aim To compare the diagnostic quality of time-of-flight magnetic resonance angiography (TOF-MRA) and metal-artefact-reduction (MAR) flat-panel-detector computed tomography angiography (FPCTA) and to determine the imaging technique best suited for evaluation endovascular and surgically treated aneurysms. Methods The image quality of TOF-MRA and MAR-FPCTA of 44 intracranial implants (coiling: n= 20; clipping: n= 15; coiling + stenting: n= 9) in a patient cohort of 25 was evaluated by two independent readers. Images obtained using MAR-FPCTA (20 second scan time, 496 projections, intravenous contrast medium administration; Artis Zee, Siemens Healthcare, Forchheim) were compared with TOF-MRA-ima…
EEG Data Quality: Determinants and Impact in a Multicenter Study of Children, Adolescents, and Adults with Attention-Deficit/Hyperactivity Disorder (…
2021
Electroencephalography (EEG) represents a widely established method for assessing altered and typically developing brain function. However, systematic studies on EEG data quality, its correlates, and consequences are scarce. To address this research gap, the current study focused on the percentage of artifact-free segments after standard EEG pre-processing as a data quality index. We analyzed participant-related and methodological influences, and validity by replicating landmark EEG effects. Further, effects of data quality on spectral power analyses beyond participant-related characteristics were explored. EEG data from a multicenter ADHD-cohort (age range 6 to 45 years), and a non-ADHD sc…
Advances in microgeophysics for engineering and cultural heritage
2009
A large number of unconventional investigations have been implemented, tested, and validated in the field of microgeophysics, with the aim being to solve specific diagnostic and/or monitoring problems regarding civil engineering and cultural heritage studies. The investigations were carried out using different tomographic 2D and 3D approaches as well as different energy sources, namely sonic, ultrasonic and electromagnetic (radar) waves, electric potential fields, and infrared thermography. Many efforts have been made to modify instruments and procedures in order to improve the resolution of the surveys as well as to greatly reduce the time of the measurements without any loss of informatio…
Le cimetière du second âge du Fer de Lailly au-delà de l'eau (Yonne) : découvertes anciennes et fouilles récentes
2023
Die Nekropole von Lailly Au-delà de l’Eau (Departement Yonne) war 1927 entdeckt worden und wurde1934, 1936 und 1937 und zum letzten Mal 2012 teilweise ausgegraben. Die Untersuchung der in den Depots der Museen von Senswiederentdeckten Grabbeigaben und die systematische Aufarbeitung der Grabungsarchive der Société archéologique de Sens habenes ermöglicht, einen Teil der geschlossenen Fundkontexte zu rekonstruieren und eine Belegungschronologie dieser kleinen Nekropolevorzuschlagen, deren großes wissenschaftliches Potenzial noch in situ erforscht werden muss. Die Studie der Grabsitten hat es zudemerlaubt, die Funde in den regionalen und überregionalen soziokulturellen Kontext zu einzuordnen
Objects as artifacts: synchronic convergence in multilingual contexts
2011
In this paper, I propose a shift in analytic focus from language to artifacts – that is, to personally meaningful objects that surface in interaction and generate talk – as a means of accounting for the historical dimension of the relationship between form and meaning. Artifacts activate memories and feelings from other times and places, informing ways of speaking in the conversational here-and-now. By applying discourse analysis to a conversation recorded during fieldwork at a social center for Spanish senior citizens in Paris, I show how various timescales – that is, the microgenetic scale of unfolding talk, the “series of connected discourse events” over weeks, months or even years, and …
Mi descrivi il tuo disegno del Mattoncino Lego? Un’esperienza didattica di matematica nella scuola dell’infanzia
2018
La consapevolezza dell’importanza di guardare, attraverso una lente di tipo matematico, i disegni prodotti dai bambini, considerandoli come strumento diagnostico per quello che D’Amore et al. (2004) chiamano come il “Campo di Esperienza” Spazio, Ordine e Misura, ha dato spunto a questo contributo che discute una sperimentazione didattica condotta in una sezione di scuola dell’infanzia (5 anni). All’interno della stessa è stato chiesto ai bambini di rappresentare dei mattoncini Lego con un disegno, e di descrivere successivamente i propri elaborati rintracciando e argomentando in essi eventuali segni di scarto numerico-spaziali rispetto al mattoncino osservato/manipolato, attraverso visioni …
FORME E FUNZIONI DEI SIMULACRI E DEI FANTOCCI ANIMATI NELLE FESTE SICILIANE
2021
In Sicilia, in occasione di numerose cerimonie religiose, soprattutto a Pasqua, entrano in scena statue con arti mobili (soprattutto Crocifissi e Madonne) e fantocci antropomorfi o teriomorfi animati da un manipolatore posto al loro interno. Se dal punto di vista fenomenologico, questi ultimi artefatti, costituiscono un ibrido, un incrocio tra umano e artificiale, dai punti di vista funzionale e simbolico, sia che rappresentino i santi apostoli sia che rappresentino eroi fondatori o animali leggendari, si pro-pongono, sempre e comunque, come entità altre dall’umano. I fantocci animati, pertanto, al pari dei mascherati e dei simulacri processionali dei santi, sono da considerarsi delle epifa…
Inventing New Uses for Tools: A Cognitive Foundation for Studies on Appropriation
2008
Appropriation refers to the processes that take place when new uses are invented for tools and when these uses develop into practices and start spreading within a user community. Most research in human–computer interaction and computersupported cooperative work to date has studied this phenomenon from a social sciences approach, thus focusing on the practice side of the phenomenon. This paper addresses appropriation from the other direction, drawing from ecological psychology and focusing on cognitive processes in context. Appropriation from this perspective is understood as an interpretation process in which the user perceives in a tool a new opportunity for action, thus acquiring a new me…