Saturation-recovery metabolic-exchange rate imaging with hyperpolarized [1-13C] pyruvate using spectral-spatial excitation
Saturation-recovery metabolic-exchange rate imaging with hyperpolarized [1-13C] pyruvate using spectral-spatial excitation
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DOI：
10.1002/mrm.24353
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发表时间：
2013-05-01
影响因子：
3.3
通讯作者：
Wiesinger, Florian
中科院分区：
文献类型：
--
作者：
Schulte, Rolf F.;Sperl, Jonathan I.;Wiesinger, Florian
在过去的十年中，超极化[1- 13 C]丙酮酸盐化学位移成像已经证明了代谢MR成像在肿瘤学、心脏病学和神经病学中的广泛应用的令人印象深刻的潜力。在这项工作中，描述了一种高效的脉冲序列的时间分辨，多层化学位移成像的注入基板和获得的下游代谢物。使用频谱空间激发结合单次激发螺旋数据采集，整体编码均匀分布在激发和信号接收之间，允许每次激发编码一个完整的二维代谢物图像。信噪比可以灵活地调整和优化使用较低的翻转角的丙酮酸底物和较大的下游代谢物。选择性地将下游代谢物的激发调节到90度导致所谓的饱和-恢复方案，其中检测到的信号含量通过可用丙酮酸盐的正向转化来确定。在重复激发的情况下，使用丙酮酸盐的较小翻转角来保持偏振。代谢交换率确定空间解析的代谢物图像使用一个简化的两个网站交换模型。这种新的对比度是朝着更定量的代谢成像迈出的重要一步。这项工作的目的是推导，分析和实施这种饱和恢复代谢交换率成像，并证明其在四只大鼠皮下肿瘤的能力。Magn Reson Med，2013年。(c)2012 Wiley Periodicals，Inc.
Within the last decade hyperpolarized [1-13C] pyruvate chemical-shift imaging has demonstrated impressive potential for metabolic MR imaging for a wide range of applications in oncology, cardiology, and neurology. In this work, a highly efficient pulse sequence is described for time-resolved, multislice chemical shift imaging of the injected substrate and obtained downstream metabolites. Using spectral-spatial excitation in combination with single-shot spiral data acquisition, the overall encoding is evenly distributed between excitation and signal reception, allowing the encoding of one full two-dimensional metabolite image per excitation. The signal-to-noise ratio can be flexibly adjusted and optimized using lower flip angles for the pyruvate substrate and larger ones for the downstream metabolites. Selectively adjusting the excitation of the down-stream metabolites to 90 degrees leads to a so-called saturation-recovery scheme with the detected signal content being determined by forward conversion of the available pyruvate. In case of repetitive excitations, the polarization is preserved using smaller flip angles for pyruvate. Metabolic exchange rates are determined spatially resolved from the metabolite images using a simplified two-site exchange model. This novel contrast is an important step toward more quantitative metabolic imaging. Goal of this work was to derive, analyze, and implement this saturation-recovery metabolic exchange rate imaging and demonstrate its capabilities in four rats bearing subcutaneous tumors. Magn Reson Med, 2013. (c) 2012 Wiley Periodicals, Inc.