Division of Imaging Sciences & Biomedical Engineering, King's College London, The Rayne Institute, 4th Floor Lambeth Wing, St. Thomas' Hospital, Lambeth Palace Rd., London, SE1 7EH, UK.
J Mol Cell Cardiol. 2011 Nov;51(5):640-50. doi: 10.1016/j.yjmcc.2011.07.005. Epub 2011 Jul 14.
Myocardial hypoxia is a major factor in the pathology of cardiac ischemia and myocardial infarction. Hypoxia also occurs in microvascular disease and cardiac hypertrophy, and is thought to be a prime determinant of the progression to heart failure, as well as the driving force for compensatory angiogenesis. The non-invasive delineation and quantification of hypoxia in cardiac tissue therefore has the potential to be an invaluable experimental, diagnostic and prognostic biomarker for applications in cardiology. However, at this time there are no validated methodologies sufficiently sensitive or reliable for clinical use. PET imaging provides real-time spatial information on the biodistribution of injected radiolabeled tracer molecules. Its inherent high sensitivity allows quantitative imaging of these tracers, even when injected at sub-pharmacological (≥pM) concentrations, allowing the non-invasive investigation of biological systems without perturbing them. PET is therefore an attractive approach for the delineation and quantification of cardiac hypoxia and ischemia. In this review we discuss the key concepts which must be considered when imaging hypoxia in the heart. We summarize the PET tracers which are currently available, and we look forward to the next generation of hypoxia-specific PET imaging agents currently being developed. We describe their potential advantages and shortcomings compared to existing imaging approaches, and what is needed in terms of validation and characterization before these agents can be exploited clinically.
心肌缺氧是心脏缺血和心肌梗死病理的主要因素。缺氧也发生在微血管疾病和心肌肥厚中，并且被认为是导致心力衰竭进展的主要决定因素，也是代偿性血管生成的驱动力。因此，非侵入性描绘和量化心脏组织中的缺氧有可能成为心脏病学应用中非常有价值的实验、诊断和预后生物标志物。然而，目前还没有足够敏感或可靠的经过验证的方法用于临床应用。PET 成像提供了关于注射放射性示踪剂分子生物分布的实时空间信息。其固有的高灵敏度允许对这些示踪剂进行定量成像，即使以亚药理（≥pM）浓度注射，也可以在不干扰生物系统的情况下对其进行非侵入性研究。因此，PET 是描绘和量化心脏缺氧和缺血的一种有吸引力的方法。在这篇综述中，我们讨论了在心脏成像中必须考虑的关键概念。我们总结了目前可用的 PET 示踪剂，并展望了目前正在开发的下一代缺氧特异性 PET 成像剂。我们描述了它们与现有成像方法相比的潜在优势和缺点，以及在这些试剂能够在临床上得到利用之前在验证和表征方面的需求。
