Shah N Jon, Kaffanke Joachim B, Romanzetti Sandro
Institute of Neuroscience and Medicine 4, Forschungszentrum Jülich GmbH, Jülich, Germany.
J Magn Reson. 2009 Aug;199(2):136-45. doi: 10.1016/j.jmr.2009.01.036. Epub 2009 Feb 4.
Single point imaging methods such as SPRITE are often the technique of choice for imaging fast-relaxing nuclei in solids. Single point imaging sequences based on SPRITE in their conventional form are ill-suited for in vivo applications since the acquisition time is long and the SAR is high. A new sequence design is presented employing variable repetition times and variable flip angles in order to improve the characteristics of SPRITE for in vivo applications. The achievable acquisition time savings as well as SAR reductions and/or SNR increases afforded by this approach were investigated using a resolution phantom as well as PSF simulations. Imaging results in phantoms indicate that acquisition times may be reduced by up to 70% and the SAR may be reduced by 40% without an appreciable loss of image quality.
诸如SPRITE之类的单点成像方法通常是对固体中快速弛豫核进行成像的首选技术。基于传统形式的SPRITE的单点成像序列不适用于体内应用，因为采集时间长且比吸收率高。提出了一种新的序列设计，采用可变重复时间和可变翻转角，以改善SPRITE在体内应用的特性。使用分辨率体模以及点扩散函数模拟研究了这种方法可实现的采集时间节省以及比吸收率降低和/或信噪比增加的情况。体模成像结果表明，采集时间可减少多达70%，比吸收率可降低40%，而图像质量不会有明显损失。
