1,720,995 research outputs found
Development of a New Cancer Diagnostic Method Using Diffusion MRI
No full text現在のがん治療は細分化が進んでおり，より適切な治療決定に繋がる様な新たな画像診断法の開発が重要であると考えられる。拡散MRIは生体内の水分子のブラウン運動による拡散現象を観察可能であり，拡散MRIから得られる定量値ががんの診断や再発，予後予測に役立つような，新たな診断法を開発している。また拡散MRI定量値の標準化も重要な課題である。本稿では拡散MRIに関する，IVIMや非ガウス拡散MRIを始めとする最先端のがんイメージング研究開発や標準化に向けた取り組みを紹介する。Cancer treatment is becoming increasingly specialized. It is hence important to develop diagnostic imaging tools that will guide the making of appropriate treatment decisions. Diffusion MRI allows the observation of the diffusion of water molecules in a living body, reflecting the tissue microstructure. We are developing new quantitative markers from diffusion MRI, which will be useful for the diagnosis of cancer recurrence and for assessing the prognosis. Another important issue is the standardization of the quantitative values obtained from diffusion MRI. This paper introduces state-of-the-art cancer imaging research, developments concerning Diffusion MRI and our efforts toward its standardization
Diffusion-Weighted Whole Body Imaging With Background Body Signal Suppression (DWIBS)
Full text linkDiffusion-weighted whole-body imaging with background body signal suppression (DWIBS) is a technique designed for whole-body screening of cancer. In the breast, it can provide stable fat suppression and excellent contrast between the tumor and the background mammary glandular tissue. Thanks to its effective attenuation of surface body fat, DWIBS is useful to depict lesions on maximum intensity projection images, and this feature translates into an efficient reading speed. Therefore DWIBS is a promising magnetic resonance imaging (MRI) method for noncontrast-enhanced breast cancer screening. However, it is important to use DWIBS in combination with other sequences because only relying on the detection of high-signal-intensity areas on DWIBS could result in a high number of false positives. In addition, because the image quality of DWIBS may vary across scanner vendors, but also between the same types of scanners of the same vendor, some standardization is necessary to continuously check and monitor image quality to ensure that the signal intensity of the mammary gland is sufficiently higher than that of the surrounding fat.</p
Perfusion-driven Intravoxel Incoherent Motion (IVIM) MRI in Oncology: Applications, Challenges, and Future Trends
Full text linkRecent developments in MR hardware and software have allowed a surge of interest in intravoxel incoherent motion (IVIM) MRI in oncology. Beyond diffusion-weighted imaging (and the standard apparent diffusion coefficient mapping most commonly used clinically), IVIM provides information on tissue microcirculation without the need for contrast agents. In oncology, perfusion-driven IVIM MRI has already shown its potential for the differential diagnosis of malignant and benign tumors, as well as for detecting prognostic biomarkers and treatment monitoring. Current developments in IVIM data processing, and its use as a method of scanning patients who cannot receive contrast agents, are expected to increase further utilization. This paper reviews the current applications, challenges, and future trends of perfusion-driven IVIM in oncology
低リスク非浸潤性乳管癌のMRI上のバイオマーカーとしてのみかけの拡散係数 : パイロット研究
Full text link京都大学0048新制・課程博士博士(医学)甲第18128号医博第3848号新制||医||1001(附属図書館)30986京都大学大学院医学研究科医学専攻(主査)教授 福山 秀直, 教授 戸井 雅和, 教授 平岡 眞寛学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDGA
Flow-Compensated IVIM in the Ballistic Regime: Data Acquisition, Modeling and Brain Applications
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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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