Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, NC, 27710, USA.
Contrast Media Mol Imaging. 2014 Mar-Apr;9(2):161-8. doi: 10.1002/cmmi.1557.
Noninvasive small animal imaging techniques are essential for evaluation of cardiac disease and potential therapeutics. A novel preclinical iodinated contrast agent called eXIA 160 has recently been developed, which has been evaluated for micro-CT cardiac imaging. eXIA 160 creates strong contrast between blood and tissue immediately after its injection and is subsequently taken up by the myocardium and other metabolically active tissues over time. We focus on these properties of eXIA and show its use in imaging myocardial infarction in mice. Five C57BL/6 mice were imaged ~2 weeks after left anterior descending coronary artery ligation. Six C57BL/6 mice were used as controls. Immediately after injection of eXIA 160, an enhancement difference between blood and myocardium of ~340 HU enabled cardiac function estimation via 4D micro-CT scanning with retrospective gating. Four hours post-injection, the healthy perfused myocardium had a contrast difference of ~140 HU relative to blood while the infarcted myocardium showed no enhancement. These differences allowed quantification of infarct size via dual-energy micro-CT. In vivo micro-SPECT imaging and ex vivo triphenyl tetrazolium chloride (TTC) staining provided validation for the micro-CT findings. Root mean squared error of infarct measurements was 2.7% between micro-CT and SPECT, and 4.7% between micro-CT and TTC. Thus, micro-CT with eXIA 160 can be used to provide both morphological and functional data for preclinical studies evaluating myocardial infarction and potential therapies. Further studies are warranted to study the potential use of eXIA 160 as a CT molecular imaging tool for other metabolically active tissues in the mouse.
非侵入性小动物成像技术对于评估心脏疾病和潜在治疗方法至关重要。最近开发了一种新型的临床前碘基对比剂，称为 eXIA 160，已用于 micro-CT 心脏成像评估。eXIA 160 在注射后立即在血液和组织之间产生强烈的对比，随后随着时间的推移被心肌和其他代谢活跃的组织吸收。我们专注于 eXIA 的这些特性，并展示其在小鼠心肌梗死成像中的应用。五只 C57BL/6 小鼠在左前降支冠状动脉结扎后约 2 周进行成像。六只 C57BL/6 小鼠作为对照。在注射 eXIA 160 后立即，血液和心肌之间的增强差异约为 340 HU，通过 4D micro-CT 扫描进行回顾性门控，可以估计心脏功能。注射后 4 小时，健康灌注的心肌与血液相比具有约 140 HU 的对比度差异，而梗死心肌没有增强。这些差异允许通过双能 micro-CT 定量梗死面积。体内 micro-SPECT 成像和体外三苯基四氮唑氯化物（TTC）染色为 micro-CT 结果提供了验证。micro-CT 和 SPECT 之间的梗死测量 RMS 误差为 2.7%，micro-CT 和 TTC 之间的 RMS 误差为 4.7%。因此，使用 eXIA 160 的 micro-CT 可用于提供形态学和功能数据，用于评估心肌梗死和潜在治疗方法的临床前研究。需要进一步的研究来研究 eXIA 160 作为 CT 分子成像工具在小鼠其他代谢活跃组织中的潜在用途。
