The present invention provides compounds with imaging moieties for imaging a subject. The present invention also relates to systems, compositions, and methods for the synthesis and use of imaging agents, or precursors thereof. An imaging agent precursor may be converted to an imaging agent using the methods described herein. In some cases, a composition or plurality of imaging agents is enriched in 18F. In some cases, an imaging agent may be used to image an area of interest in a subject, including, but not limited to, the heart, cardiovascular system, cardiac vessels, brain, and other organs.本發明提供用於對個體進行造影之具有造影部分之化合物。本發明亦關於用於合成及使用造影劑或其前驅體之系統、組合物及方法。造影劑前驅體可使用本文所述之方法轉化成造影劑。在一些情況下,組合物或複數種造影劑用18F增濃。在一些情況下,造影劑可用於對個體之相關區域進行造影,該相關區域包括(但不限於)心臟、心血管系統、心血管、腦及其他器官。