322,815 research outputs found
Prevalenza dell'effetto T2-shine-through nelle immagini pesate in Diffusione (DW) nello studio delle lesioni focali epatiche: uno studio mediante mappe ADC esponenziali
No full textConfronto tra le mappe ADC convenzionali ed esponenziali nell'analisi visiva delle lesioni focali epatiche con imaging pesato in Diffusione
No full textChest 64-row CT in the immunocompromised patient after hematopoietic stem cell transplantation with suspected pneumonia: imaging findings and diagnostic clues.
No full textSection: Learning objectives
To resume what the radiologist needs to know about the clinical history of the patient
To illustrate the state-of-art 64-row Computed Tomography (CT) protocol combining high resolution and low dose
To define the most common radiological pattern and the most specific signs of pneumonia in order to narrow the differential diagnosi
Automatic bolus tracking (ABT) vs fixed duration contrast injection (FDCI) at 64-row multidetector computer tomography (MDCT) of the upper abdomen: a comparative study.
No full textBackground
Multidetector-row Computed Tomography (MDCT), is a rapidly evolving technology suited for high demanding diagnostic skills, especially in cardiovascular and body imaging [1]. Because of the extremely rapid scan speed inherent to MDCT, acquisition protocols must be adjusted accordingly. In particular, since most abdominal examinations require intravenous (i.v.) administration of contrast medium (CM) to enhance lesions’ conspicuity, proper selection of contrast injection technique and acquisition timing represent major technical issues [2,3,4]. Especially for liver imaging, many studies have been focused to achieve optimal CM injection protocol, in order to obtain proper timing and contrast properties of each vascular phase [5,6,7,8].
At present, fixed rate CM injection monitored by automatic bolus-tracking (ABT) is the most commonly used technique in multiphasic liver imaging [6]. ABT compensates for individual variations in circulation time that may affect arterial phase. Nonetheless, this approach determines adjunctive radiation exposure [9]. In the last years, fixed duration contrast injection (FDCI) has been advocated as a valid alternative to ABT in achieving optimal arterial phase without additional radiation dose and by simplifying examinations work-flow [5]. A large amount of literature compares ABT vs. FDCI for liver imaging, mostly on 8 or 16-row MDCT [6,9,10,11,12]. To our knowledge, no previous studies investigated whether these techniques provide comparable liver contrast enhancement by using 64-row MDCT, i.e. at even faster acquisition time.
Purpose
On these basis, the purpose of our study was to quantitatively and qualitatively evaluate ABT vs. FDCI contrast enhancement of the liver by using a 64-MDCT scanner.
Background
Multidetector-row Computed Tomography (MDCT), is a rapidly evolving technology suited for high demanding diagnostic skills, especially in cardiovascular and body imaging [1]. Because of the extremely rapid scan speed inherent to MDCT, acquisition protocols must be adjusted accordingly. In particular, since most abdominal examinations require intravenous (i.v.) administration of contrast medium (CM) to enhance lesions’ conspicuity, proper selection of contrast injection technique and acquisition timing represent major technical issues [2,3,4]. Especially for liver imaging, many studies have been focused to achieve optimal CM injection protocol, in order to obtain proper timing and contrast properties of each vascular phase [5,6,7,8].
At present, fixed rate CM injection monitored by automatic bolus-tracking (ABT) is the most commonly used technique in multiphasic liver imaging [6]. ABT compensates for individual variations in circulation time that may affect arterial phase. Nonetheless, this approach determines adjunctive radiation exposure [9]. In the last years, fixed duration contrast injection (FDCI) has been advocated as a valid alternative to ABT in achieving optimal arterial phase without additional radiation dose and by simplifying examinations work-flow [5]. A large amount of literature compares ABT vs. FDCI for liver imaging, mostly on 8 or 16-row MDCT [6,9,10,11,12]. To our knowledge, no previous studies investigated whether these techniques provide comparable liver contrast enhancement by using 64-row MDCT, i.e. at even faster acquisition time.
Purpose
On these basis, the purpose of our study was to quantitatively and qualitatively evaluate ABT vs. FDCI contrast enhancement of the liver by using a 64-MDCT scanner
Valore predittivo negativo della Risonanza Magnetica (RM) a 3.0T nella diagnosi di neoplasia prostatica in pazienti con valori di PSA in "zona grigia" e pregresse biopsie negative
No full textDiffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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