1,720,977 research outputs found
L'ecotomografia Doppler ad alta risoluzione in tempo reale nel protocollo diagnostico dell'ischemia cerebrale del distretto carotideo e la dissezione spontanea della carotide interna cervicale
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Intraoperative sonography for spinal tumors. Correlations with MR findings and surgery.
No full textTo investigate the role of intraoperative ultrasonography during surgery for spinal tumors and the correlation between echographic, magnetic resonance and surgical findings.Twenty patients with spinal tumor, explored by MRI of the spine, have been treated with ultrasound-guided surgery. The ultrasound exploration has been performed during laminectomy on the dural surface in all cases and, after the dural opening, on the spinal cord surface for intramedullary tumors.In all patients the ultrasound exploration has allowed to exactly define the extent of the laminectomy, the dural opening and the myelotomy. Meningiomas were hyperechoic and homogeneous, with well defined margins and often visible hyperechoic dural attachment; neurinomas were less hyperechoic and less homogeneous than meningiomas. Intramedullary tumors showed hyperechoic solid and hypoechoic cystic-necrotic components, although a specific tissue characterization (tumor infiltration, gliosis, edema) is not possible.Intraoperative ultrasonography should be used routinely during surgery for spinal tumors in order to reduce the extent of the laminectomy, dural opening and myelotomy. A good correlation exists between signal intensity on T1-weighted images of MR, the echographic aspect of the tumor and the pathological findings at operation
Olfactory groove meningioma and multiple aneurysms. Case report.
No full textWe report a case of a patient with olfactory groove meningioma associated with multiple aneurysms. The association between intracranial aneurysms and meningiomas is infrequent and perhaps it is due to chance alone; many theories have been formulated to explain it. In the cases with both lesions, meningiomas are more frequently located at level of the convexity while aneurysms are more often located at level of the anterior cerebral-anterior communicating artery complex or at level of the middle cerebral artery
Coiling of the vertebral artery presenting with neuralgic pain.
No full textA rare case of radicular pain in the arm due to compression of the C6 nerve root by coiling of the vertebral artery is reported; the diagnosis was confirmed by computed tomography (CT), magnetic resonance (MR) angiography and echocolordoppler. Although the enlargement of an intervertebral foramen by a tortuous vertebral artery has been described previously, the occurrence of radicular pain is exceptional. Magnetic resonance imaging (MRI), MR angiography and echocolordoppler allow to differentiate foraminal enlargement due to vascular anomalies of the vertebral artery from that more commonly due to tumor compression, mainly from neurinoma. Surgical decompression may be considered in symptomatic cases
The role of real time B-mode ultrasonography in the follow-up of patients submitted to carotid endarterectomy.
No full textSixty-eight patients submitted to carotid endarterectomy for carotid stenosis have been studied periodically by B-mode real time ultrasonography. This non-invasive investigation allows to detect not only a recurrent stenosis, but also minor changes following endarterectomy, including suture, lesions from clamps, myointimal proliferation, and intimal flaps. We think that all patients submitted to carotid endarterectomy must be explored periodically by duplex scanning, in order to follow-up the normal and pathological changes of the arterial wall
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
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