Milshteyn Eugene, von Morze Cornelius, Reed Galen D, Shang Hong, Shin Peter J, Zhu Zihan, Chen Hsin-Yu, Bok Robert, Goga Andrei, Kurhanewicz John, Larson Peder E Z, Vigneron Daniel B
Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA, USA.
Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA.
Magn Reson Imaging. 2017 May;38:152-162. doi: 10.1016/j.mri.2017.01.003. Epub 2017 Jan 7.
The goal of this project was to develop and apply techniques for T mapping and 3D high resolution (1.5mm isotropic; 0.003cm) C imaging of hyperpolarized (HP) probes [1-C]lactate, [1-C]pyruvate, [2-C]pyruvate, and [C,N]urea in vivo. A specialized 2D bSSFP sequence was implemented on a clinical 3T scanner and used to obtain the first high resolution T maps of these different hyperpolarized compounds in both rats and tumor-bearing mice. These maps were first used to optimize timings for highest SNR for single time-point 3D bSSFP acquisitions with a 1.5mm isotropic spatial resolution of normal rats. This 3D acquisition approach was extended to serial dynamic imaging with 2-fold compressed sensing acceleration without changing spatial resolution. The T mapping experiments yielded measurements of T values of >1s for all compounds within rat kidneys/vasculature and TRAMP tumors, except for [2-C]pyruvate which was ~730ms and ~320ms, respectively. The high resolution 3D imaging enabled visualization the biodistribution of [1-C]lactate, [1-C]pyruvate, and [2-C]pyruvate within different kidney compartments as well as in the vasculature. While the mouse anatomy is smaller, the resolution was also sufficient to image the distribution of all compounds within kidney, vasculature, and tumor. The development of the specialized 3D sequence with compressed sensing provided improved structural and functional assessments at a high (0.003cm) spatial and 2s temporal resolution in vivo utilizing HP C substrates by exploiting their long T values. This 1.5mm isotropic resolution is comparable to H imaging and application of this approach could be extended to future studies of uptake, metabolism, and perfusion in cancer and other disease models and may ultimately be of value for clinical imaging.
本项目的目标是开发并应用技术，用于对超极化（HP）探针[1 - C]乳酸盐、[1 - C]丙酮酸盐、[2 - C]丙酮酸盐和[C,N]尿素进行T映射以及三维高分辨率（各向同性1.5毫米；0.003厘米）C成像。在临床3T扫描仪上实施了一种专门的二维稳态自由进动（bSSFP）序列，并用于获取大鼠和荷瘤小鼠体内这些不同超极化化合物的首张高分辨率T映射图。这些映射图首先用于优化定时，以在正常大鼠的各向同性空间分辨率为1.5毫米的单时间点三维bSSFP采集中获得最高信噪比。这种三维采集方法扩展到了具有2倍压缩感知加速的序列动态成像，而不改变空间分辨率。T映射实验得出，除了[2 - C]丙酮酸盐（分别约为730毫秒和320毫秒）外，大鼠肾脏/血管系统和TRAMP肿瘤内所有化合物的T值测量结果均>1秒。高分辨率三维成像能够可视化[1 - C]乳酸盐、[1 - C]丙酮酸盐和[2 - C]丙酮酸盐在不同肾段以及血管系统中的生物分布。虽然小鼠的解剖结构较小，但该分辨率也足以对所有化合物在肾脏、血管系统和肿瘤内的分布进行成像。利用超极化C底物的长T值，通过开发具有压缩感知的专门三维序列，在体内以高（0.003厘米）空间分辨率和2秒时间分辨率提供了改进的结构和功能评估。这种1.5毫米各向同性分辨率与氢成像相当，该方法的应用可扩展到未来对癌症和其他疾病模型中的摄取、代谢和灌注的研究，最终可能对临床成像有价值。
