国产bbaaaaa片,成年美女黄网站色视频免费,成年黄大片,а天堂中文最新一区二区三区,成人精品视频一区二区三区尤物

首頁(yè)> 外文學(xué)位 >Magnetic resonance imaging of semi-solid tissues.
【24h】

Magnetic resonance imaging of semi-solid tissues.

機(jī)譯：半固體組織的磁共振成像。

獲取原文
獲取原文并翻譯 | 示例
  • 摘要
  • 著錄項(xiàng)
  • 相似文獻(xiàn)
  • 相關(guān)主題

摘要

Magnetic resonance imaging (MRI) is a powerful medical imaging modality that provides unique and flexible tissue contrast. It uses no ionizing radiation and can image arbitrary scan planes. MRIs have excellent contrast for soft tissues, such as gray and white matter in the brain, muscles, bone marrow, and internal organs, and also for blood and other fluids. However, conventional imaging methods have little to no signal from solid and semi-solid tissues, such as tendons, ligaments, menisci, cortical and trabecular bone, and many other connective and structured tissues in the body. These solid and semi-solid tissues are characterized by their short transverse relaxation time, T2, and can be imaged with an MRI technique known as ultra-short echo time (UTE) imaging. This dissertation will present two novel methods for improving the contrast of these tissues and a set of design algorithms for improving the imaging efficiency that also can be applied to some other MRI techniques.; The contrast of tissues with short-T2 values can be improved by suppressing the signal from tissues with long- T2 values, such as fluid and soft tissues. The first method is based on RF pulses, and provides precise long-T2 component suppression. It is an improvement in robustness over previous suppression pulses and can also include fat suppression. The second method is similarly based on RF pulses, and is additionally robust to RF inhomogeneities, improving the reliability of the suppression.; A set of algorithms was developed to improve the scan efficiency of semi-solid tissue imaging. These algorithms design variable field-of-view shapes for radial imaging techniques, allowing for imaging of non-circular and non-spherical regions that was previously unsupported. Using tailored field-of-view shapes and sizes can be used to improve the speed or quality of the images, and also allows for new radial imaging applications. In addition to semi-solid tissue imaging, radial techniques are also used for cardiac imaging, angiography, and diffusion imaging applications, all of which will also benefit from these design algorithms.
機(jī)譯：磁共振成像（MRI）是一種強(qiáng)大的醫(yī)學(xué)成像方法，可提供獨(dú)特而靈活的組織對(duì)比度。它不使用電離輻射，并且可以對(duì)任意掃描平面成像。 MRI對(duì)軟組織（例如大腦，肌肉，骨髓和內(nèi)臟的灰白色物質(zhì)）以及血液和其他液體的對(duì)比度極佳。但是，傳統(tǒng)的成像方法幾乎沒(méi)有或幾乎沒(méi)有來(lái)自實(shí)體和半實(shí)體組織的信號(hào)，例如肌腱，韌帶，半月板，皮質(zhì)和小梁的骨以及人體中許多其他結(jié)締組織和結(jié)構(gòu)化組織。這些實(shí)體和半實(shí)體組織的特征在于其較短的橫向弛豫時(shí)間T2，并且可以使用稱為超短回波時(shí)間（UTE）成像的MRI技術(shù)進(jìn)行成像。本論文將介紹兩種改善這些組織對(duì)比度的新穎方法，以及一套可以提高成像效率的設(shè)計(jì)算法，這些算法也可以應(yīng)用于其他一些MRI技術(shù)。具有T2值短的組織的對(duì)比度可以通過(guò)抑制來(lái)自具有T2值長(zhǎng)的組織（例如液體和軟組織）的信號(hào)來(lái)改善。第一種方法基于RF脈沖，并提供精確的長(zhǎng)T2分量抑制。與以前的抑制脈沖相比，它具有更高的魯棒性，并且還可以抑制脂肪。第二種方法類似地基于RF脈沖，并且對(duì)于RF不均勻性也很健壯，從而提高了抑制的可靠性。開(kāi)發(fā)了一套算法來(lái)提高半固體組織成像的掃描效率。這些算法為徑向成像技術(shù)設(shè)計(jì)了可變的視場(chǎng)形狀，從而可以對(duì)以前不受支持的非圓形和非球形區(qū)域進(jìn)行成像。使用量身定制的視場(chǎng)形狀和大小可用于提高圖像的速度或質(zhì)量，也可用于新的徑向成像應(yīng)用。除半實(shí)體組織成像外，放射線技術(shù)還用于心臟成像，血管造影和擴(kuò)散成像應(yīng)用，所有這些技術(shù)也將從這些設(shè)計(jì)算法中受益。

著錄項(xiàng)

相似文獻(xiàn)

  • 外文文獻(xiàn)
  • 中文文獻(xiàn)
  • 專利
獲取原文

客服郵箱：kefu@zhangqiaokeyan.com

京公網(wǎng)安備：11010802029741號(hào) ICP備案號(hào)：京ICP備15016152號(hào)-6 六維聯(lián)合信息科技 (北京) 有限公司?版權(quán)所有

  • 客服微信

  • 服務(wù)號(hào)