1,720,964 research outputs found
Color Doppler US of the postoperative penis: Anatomy and surgical complications
No full textA number of surgical procedures that significantly change the penile anatomy and vasculature can be used to manage pathologic conditions of the penis (eg, congenital and acquired deformities, erectile dysfunction, priapism). Phallic reconstruction surgery can be used for sex reassignment and after penile amputation or for correction of congenital malformations. Color Doppler ultrasonography (US) clearly depicts the normal penile anatomy and postoperative changes (eg, changes of the tunica albuginea, extraalbugineal pathologic fluid collections, cavernosal tissue changes produced by scars and fibrosis). It is also effective in evaluating surgery-related complications and determining the causes of erectile dysfunction and other unsatisfactory long-term results. Moreover, color Doppler US of the penile vessels and vascular anastomoses following revascularization allows direct evaluation of flow characteristics, shunt patency, and venous engorgement. Color Doppler US is the imaging modality of choice in evaluating patients who have undergone penile surgery
Visualization of peri-prostatic neurovascular fibers before and after radical prostatectomy by means of diffusion tensor imaging (DTI) with clinical correlations: preliminary report
No full textTo evaluate if diffusion tensor imaging (DTI) is able to detect morphological changes of peri-prostatic neurovascular fibers (PNF) before and after robot-assisted radical prostatectomy (RARP) and if these changes are related to urinary incontinence (UI) and erectile dysfunction (ED). From October 2014 and August 2017, 26 patients with biopsy-proven prostate cancer underwent prostatic multiparametric magnetic resonance imaging (mp-MRI) including DTI sequencing before, and 6 months after, RARP. Images were analyzed by placing six regions of interest (ROI), respectively, at base, mid gland, and apex, one for each side, to obtain tractographic reconstruction of the PNF. Patients were asked to complete International Consultation Incontinence Questionnaire-Short Form (ICIQ-SF) and International Index of Erectile Function (IIEF-5) questionnaires before RARP and 6 months post-operatively. Fractional anisotropy (FA), number (N), and length (L) of PNF before and after RARP were compared by means of Student's t test; Spearman's test was used to evaluate correlation between DTI parameters and questionnaires' scores. We observed a significant difference in N values before and after RARP (p < 0.001) and a negative correlation between IIEF-5 score and post-operative FA values at both the right (rho = - 0.42; p = 0.0456) and left (rho = - 0.66; p = 0.0006) base of the prostate. DTI with tractography of PNF is able to detect quantitative changes in N, L, and FA values in PNF after RARP. In particular, we observed an inverse correlation between FA of PNF and ED at 6 months after RARP. Further investigations are needed to confirm this trend
Serous Neoplasms
No full textSerous pancreatic neoplasms are cystic tumors, usually detected as solitary lesions. The most common is the serous cystadenoma (SCA).
SCA typically presents as a solitary multilocular microcystic lesion with a honeycomb architecture
Changes in cerebral activity after decreased upper-limb hypertonus: An EMG-fMRI study
No full textOBJECTIVE:
Whereas several studies have used functional magnetic resonance imaging (fMRI) to investigate motor recovery, whether therapy to decrease post-stroke hypertonus alters central motor patterns remains unclear. In this study, we used continuous electromyography (EMG)-fMRI to investigate possible changes in movement-related brain activation in patients receiving Botulinum toxin (BoNT-A) for hand-muscle hypertonus after chronic stroke.
METHODS:
We studied eight stroke patients all of whom had hemiparesis and associated upper-limb hypertonus. All patients underwent an fMRI-EMG recording and clinical-neurological assessment before BoNT-A and 5 weeks thereafter. The handgrip motor task during imaging was fixed across both patients and controls. The movements were metronome paced, movement amplitude and force were controlled with a plastic orthosis, dynamometer and EMG recording. An age-matched control group was recruited from among healthy volunteers underwent the same fMRI-EMG recording.
RESULTS:
Before BoNT-A, while patients moved the paretic hand, fMRI detected wide bilateral activation in the sensorymotor areas (SM1), in the supplementary motor area (SMA) and cerebellum. After BoNT-A blood oxygenation level-dependent (BOLD) activation decreased in ipsilateral and contralateral motor areas and became more lateralized. BOLD activation decreased also in ipsilateral cerebellar regions and in the SMA.
CONCLUSION:
Changes in peripheral upper-limb hypertonus after BoNT-A were associated to an improvement in active movements and more lateralized and focalized activation of motor areas. The clinical and EMG-fMRI coregistration technique we used to study hand-muscle hypertonus in patients receiving BoNT-A after chronic stroke should be useful in future studies seeking improved strategies for post-stroke neurorehabilitation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Secretin-enhanced MR imaging of the pancreas
No full textSecretin is a hormone that stimulates the exocrine pancreatic secretion of bicarbonate-rich fluid from the acinar cells of the pancreas that accumulates within the pancreatic ductal lumen. The exogenous administration of secretin improves the visualization of pancreatic ducts at magnetic resonance (MR) cholangiopancreatography (MRCP), because of an enlargement of the pancreatic duct system and an increase of the fluid content within the lumen of the pancreatic ducts, responsible of an increase of MR signal. In this review, the technique of secretin-enhanced MRCP, which has the aim to depict the whole pancreatic duct system, the biliary tree, the major and minor papillae, and the duodenum, will be described. Because of the anatomic contiguity between the pancreas and the gastrointestinal tract, the presence of fluid within the stomach may overlap with the pancreatic duct system and therefore the pancreatic duct may be difficult to visualize, representing a potential source of diagnostic pitfalls. The technique to reduce the signal intensity of the static fluid present within the stomach and in the duodenal lumen is also described. The technique of secretin administration will be illustrated, with emphasis on the synchronization of secretin administration and MR image acquisition. Furthermore, the frequency and number of MRCP images necessary to achieve a temporal resolution adequate to visualize the physiologic changes in the pancreatic gland, induced by the administration of secretin, is described. The assessment of pancreatic, morphologic, and functional response to the administration of secretin, as depicted on MRCP images, will be illustrated. Finally, the indications for secretin-enhanced MRCP will be discussed to define which patients will benefit from secretin-enhanced MR imaging for their treatment planning
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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