Improved methods for perfusion imaging with hyperpolarized carbon-13

摘要 在发达国家，血流灌注障碍是导致死亡和残疾的主要原因。 缺血性疾病，包括心肌梗死、中风和肺栓塞是很明显的 病理灌流的表现。血流灌注在许多癌症中也起着重要作用。显然，方法 高质量的灌注成像是对患者进行放射学评估的重要优先事项。不幸的是， 灌注成像的分辨率、质量和准确性仍远远不能满足临床和研究的需要。 基于动脉自旋标记(ASL)的技术受到信号强度和短松弛的限制 标记质子的倍数。使用Gd造影剂的方法面临着以下挑战 基础灌注和由此产生的图像动力学之间的复杂关系，除了 日益增长的安全担忧。 在这里，我们建议开发稳健的新方法，通过利用超极化的 碳-13标记的可在组织中自由扩散的灌注示踪剂。示踪剂具有较长的T1和T2弛豫 时间长，在组织中的停留时间长，基本上可以在没有内源性背景的情况下成像。 因此，可以使用稳健的成像技术来监测这种制剂的时间动力学 高信号强度。我们将开发使用动态成像测量局部血流的方法 技巧。超极化灌注成像将与ASL技术进行比较，这两种方法 将对照微球灌注定量作为评估准确性和 可扩散偏振示踪剂灌注成像的重复性。

Abstract Disorders of perfusion underlie the majority of the causes of mortality and disability in the developed world. Ischemic disorders, including myocardial infarction, stroke, and pulmonary embolism are obvious manifestations of pathologic perfusion. Perfusion also plays a major role in many cancers. Clearly, methods for high quality perfusion imaging are an important priority for radiologic evaluation of patients. Unfortunately, the resolution, quality, and accuracy of perfusion imaging is still far inferior to the clinical and research needs. Techniques based on arterial spin labeling (ASL) are limited by signal strength and by the short relaxation times of labeled protons. Methods that make use of gadolinium contrast agents face challenges arising from the complex relationship between the underlying perfusion and the resulting image dynamics, in addition to growing safety concerns. Here we propose to develop robust new methods for perfusion imaging by making use of a hyperpolarized carbon-13 labeled perfusion tracer that is freely diffusible in tissue. The tracer has long T1 and T2 relaxation times and long residence times in tissue, and can be imaged with essentially no endogenous background. Consequently, the temporal dynamics of this agent can be monitored using robust imaging techniques with high signal strength. We will develop methods for measuring local blood flow using dynamic imaging techniques. Hyperpolarized perfusion imaging will be compared against ASL techniques, and both methods will be validated against microsphere perfusion quantitation as a gold standard to assess the accuracy and reproducibility of perfusion imaging with diffusible polarized tracers.