PET/MR的心脏应用(一)

向大家介绍一篇关于心脏PET/MR的综述研究“MR/PET Imaging of the Cardiovascular System” ，《JACC: CARDIOVASCULAR IMAGING》影响因子10分，属于心脏影像类的顶级期刊，其对PET/MR在心脏应用中的判断应该是相当权威的。

当前PET/CT的应用主要为心肌灌注显像(myocardial perfusion)和冠心病患者的心肌活性评估。C11标记的脂肪酸（空腹状态下，心肌能量来源为主要为脂肪酸）用于评估心肌代谢、F18-FDG用于评估心肌活性。此外、心肌炎、动脉炎等也可用F18-FDG进行评估。
一些新的MR造影剂和PET的核素药物给PET/MR的应用带来广阔前景（图1）
相对于PET/CT来说，PET/MR的射线量更少；主要是考虑到CT的心脏检查带来的剂量已经很高，如果使用多核素药物，剂量还会更高，因而通过MR/PET替代PET/CT减少辐射剂量是很重要的，尤其是对于年轻人来说。

Novel PET tracers and MR tracers for cardiovascular application.JPG

4.心脏成像方面，PET/CT和MR/PET各有优势，但MR/PET的临床研究优势更强，PET/CT图像医生更容易解读。（图2）

summary of characteristics of CT MR and PET and the combined modalities.JPG

基于MR图像进行运动校正和部分容积效应的校正是MR/PET的重要优势之一，更精准的PET图像甚至可对心脏冠脉的炎性病灶进行显影。此外，MR提供的优异软组织对比和多对比成像也是CT所不具备的。

6.现有的一些MR/PET的研究集中在如下领域：
a. PET/CT 与 MR/PET的对比研究
b. 心脏结节病
c. 冠心病
d. 心肌淀粉样变
e. 心血管粥样硬化
f. 心脏占位
g. 其他潜在的应用（图3）

summary of potential cardiovasular Uses of MRPET.JPG

MR/PET当前应用遇到的一些困难
a. 心脏的衰减矫正，表面线圈、心脏周围器官的精确分割、心脏植入物
b. 其他一些因素包括：孔径小、价格昂贵、装机量小缺乏广泛验证
总结：MR/PET scanning is an exciting novel imaging modality that can assess disease activity together with assessments of cardiac anatomy, function, and tissue composition during a single scan. The lower associated radiation doses may be particularly important for the clinical imaging of younger patients.In the research arena, beyond the ability to easily combine and co-register already established MR and PET imaging techniques into a single scan, many researchers are seeking novel complex applications that may further advance the state-of-the-art. Although technological and operational obstacles persist, these are rapidly being overcome, positioning MR/PET scans as a useful new imaging modality for
the investigation of cardiovascular disease. Further clinical trials are now required to explore the potential of this technique.