1,720,963 research outputs found
Sensorineural Hearing Loss: Pathophysiology, Diagnosis and Treatment [Chapter 5. Neuroradiology of the Hearing System]
No full textHearing loss is one of the most frequent indications for CT and MR examinations of the auditory system. Such a symptomatology is becoming increasingly common in today’s society and is extremely disturbing for patients. Causes may involve the auditory pathway at any level.
In most cases, neuroradiological examinations represents a mandatory step, within a multidisciplinary workup, towards final diagnosis, therapeutic plan and subsequent follow-ups. This chapter will introduce this critical topic starting from an imaging-based exposition of the anatomy and function of the auditory system. The chapter will include some hints on the choice of the best imaging examination to perform on each patient since the type of hearing loss determines which imaging study will yield the most diagnostic information. Practical coverage of the neuroradiological findings in conductive, sensorineural and mixed hearing loss forms will be presented. Ranging from congenital to acute and chronic causes, from children to adults, the role of imaging-based examinations will be illustrated for both common and uncommon diseases of the hearing system.
To increase reading and review experience, the authors will include concise descriptions (in a bullet outline format and/or in tables) of all the discussed key information related to anatomy, function and pathology. High-quality CT and MR images will support the reader in each paragraph for an optimal learning experience of the discussed topics
Neuroradiology of the Hearing System
No full textHearing loss is one the commonest disabling diseases affecting populations of all ages worldwide. The impairment of hearing may be the cause of impaired language development in children, the cause of scholarly issues in adolescents, the cause of worsening of quality of life in the adults, and the cause of isolation of aged people. In this book, the authors present the hearing loss in all its facets, starting from the basis of pathophysiology and anatomy, passing through the clinical and instrumental diagnosis and, finally, describing the most important diseases causing hearing loss with reasonable treatment options. A section was dedicated to the imaging of the ear with about 100 original figures. The readers will find a complete classification of genetic hearing loss and all information related to congenital deafness as well. A wide section was reserved to the description and discussion of the most important pathology leading to hearing loss (Meniere’s disease, otosclerosis, trauma and occupational hearing impairment, etc.). The treatment of hearing loss is continuously evolving with the progress of technology, and the authors gave a wide space to describe all treatment options available for the patients, providing all information useful to manage hearing disease correctly
AMBIGUOUS MR FINDINGS IN GLIOBLASTOMA REVISION OF 4 CASES FOCUSING ON DIFFUSION WEIGHTED IMAGING.
No full textWe collect 4 patients with glioblastoma showing unclear clinical presen- tation and ambiguous MRI findings; careful revision of follow-up imag- ing suggested DWI changes as the more specific tool to predict the pres- ence of underlying tumor tissue. Methods retrospective MR imaging review of 4 patients with biopsy proven diag- nosis of glioblastoma. All patients accessed Emergency Department with secondary generalized seizures. MRI examinations were performed in acute setting with different clinical orientation: ischemia, status epilepticus and encephalitis. Follow-up was scheduled after 1 month (4/ 4) and after 3 months (3/4). All MRI protocols include T2w FLAIR, DWI and post-contrast T1w images. Results&Discussion Although all glioblastomas demonstrate changes on T2 FLAIR and DW imaging before presenting rim enhancing core, DWI is more specific to predict the center core of the tumor. In each case glioblastoma apparently develops from non enhancing DWI hyperintense areas; these areas do not correspond to an evident restriction on ADC map, even if diffusivity is reduced compared to previous MR imaging and to the perilesional tissue. Actually, ADC values correlate inversely to cellular proliferation in spec- imen and in vivo acquisition; DWI changes is a powerful tool to identify proliferating tumor cells regardless of ischemic changes due to tumor neoangiogenesis. Conclusion In our experience non enhancing hyperintense areas on DWI could pre- dict the site of tumor core; DWI changes should be carefully evaluated and reported when considering unclear clinical cases with ambiguous MR findings
IMAGING OF VESTIBULAR SCHWANNOMA [Chapter 4]
No full textLesions of the cerebellopontine angle and internal auditory canal are a frequent finding in neuroradiological examinations and their detection may represent a diagnostic challenge. Among these lesions, vestibular schwannomas and meningiomas are certainly the most frequent and account for up to 90% of all cerebellopontine angle tumours. The remaining ones are a group of lesions arising from the different structures found in these anatomical regions such as haemangiomas, lipomas, lymphomas, facial nerve tumours, and aneurysms. This chapter will introduce this topic focusing on a practical coverage of the typical and atypical neuroradiological signs that will drive towards the most correct differential diagnosis checklist. High-quality neuroradiological images will support the reader for an optimal learning experience
Chapter 4. Imaging of Vestibular Schwannoma
No full textVestibular schwannoma is a rare benign tumor arising from VIII cranial nerve. Its localisation into internal auditory canal and cerebello-pontine angle is the main reason for the relevant clinical implication of such disease.
This book develops all the features regarding the vestibular schwannoma, starting from the biology of the tumor, passing to the clinical presentation and instrumental diagnostic pathway to make diagnosis and concluding with therapeutic options linked to several factors regarding tumor size, localisation, symptoms, patient characteristics and outcome.
The chapters are divided into 3 sections: pathophysiology, clinical features and treatment.
Advancements in microsurgical technique and radiosurgery, coupled with an increased understanding of the natural history of the disease, have made modern management of this tumor considerably more complex and the opinions are still divided between conservatism and definitive cure.
The last section includes the rehabilitation after treatment of patients affected by vestibular schwannoma.
The contributions to this book were done by several eminent expert authors in their field, and all references are up to date. This is a robust resource for residents, fellows, and early attending physicians, as well as mid- to later-career physicians who care for patients with vestibular schwannoma
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
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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