用（99m）锝葡糖醛酸进行成像以早期检测部分再灌注犬心肌梗死。

(99m)Tc-glucarate imaging for the early detection of infarct in partially reperfused canine myocardium.

作者信息

Johnson Gerald, Okada Christine C, Hocherman Sonia D, Liu Zhonglin, Hart Curtis, Khaw Ban-An, Okada Robert D

机构信息

University of Tulsa and the University of Oklahoma Health Sciences Center, Tulsa, OK, USA.

出版信息

Eur J Nucl Med Mol Imaging. 2006 Mar;33(3):319-28. doi: 10.1007/s00259-005-1913-x. Epub 2005 Oct 20.

DOI:10.1007/s00259-005-1913-x

PMID:16237571

Abstract

PURPOSE

(99m)Tc-glucarate is an imaging agent developed for the detection of acutely infarcted myocardium. The purposes of the current study were to (1) determine whether (99m)Tc-glucarate can detect acute infarct in the setting of only partial minimal reperfusion, (2) study the persistence and time course of scan positivity following coronary occlusion and intravenous tracer injection, (3) assess the ability of (99m)Tc-glucarate to determine infarct size, and (4) compare these data with previous results obtained using a 100% reperfusion model.

METHODS

Six dogs underwent left circumflex (LCx) coronary occlusion for 90 min, followed by 10% epicardial blood flow reperfusion. Fifteen mCi (555 MBq) (99m)Tc-glucarate was injected intravenously 30 min later. Serial gamma camera images were acquired over 240 min. Microsphere blood flow determinations were performed at baseline, during occlusion, during tracer administration, and just before euthanasia. Ex vivo gamma camera images were obtained. Triphenyltetrazolium chloride (TTC) staining was performed to assess infarct size.

RESULTS

Qualitatively, (99m)Tc-glucarate images showed a well-defined "hot spot" in all six dogs by 30 min after tracer injection (150 min following coronary occlusion), which persisted for 240 min following tracer administration. Quantitatively, there was a significant increase in the LCx/LAD (left anterior descending) counts ratio beginning 10 min after tracer administration (130 min after occlusion), and continuing to 240 min after tracer administration. Tracer retention was 12.0+/-0.9% for the LAD and 39.0+/-4.1% for the LCx hot spot zone (p<0.05) at 240 min after (99m)Tc-glucarate injection. The correlation coefficient was 0.90 for infarct size by TTC versus (99m)Tc-glucarate.

CONCLUSION

In the setting of only partial minimal coronary reperfusion following infarction, (99m)Tc-glucarate myocardial uptake is delayed and less intense compared with the setting of complete reperfusion. Nevertheless, infarcts can still be reliably detected in dogs using qualitative in vivo imaging, and significant abnormalities in quantitative parameters are observed. Thus, (99m)Tc-glucarate imaging may be useful for the clinical detection and relative sizing of acute myocardial infarction, even in the setting of only minimal coronary reperfusion.

摘要

目的

（99m）锝 - 葡糖醛酸是一种开发用于检测急性梗死心肌的显像剂。本研究的目的是：（1）确定（99m）锝 - 葡糖醛酸在仅部分轻度再灌注情况下能否检测出急性梗死；（2）研究冠状动脉闭塞及静脉注射示踪剂后扫描阳性的持续情况和时间进程；（3）评估（99m）锝 - 葡糖醛酸确定梗死面积的能力；（4）将这些数据与先前使用100%再灌注模型获得的结果进行比较。

方法

6只犬行左旋支（LCx）冠状动脉闭塞90分钟，随后进行10%的心外膜血流再灌注。30分钟后静脉注射15毫居里（555兆贝可）（99m）锝 - 葡糖醛酸。在240分钟内采集系列γ相机图像。在基线、闭塞期间、示踪剂给药期间及安乐死前不久进行微球血流测定。获取离体γ相机图像。进行氯化三苯基四氮唑（TTC）染色以评估梗死面积。

结果

定性分析，（99m）锝 - 葡糖醛酸图像显示，在示踪剂注射后30分钟（冠状动脉闭塞后150分钟），所有6只犬均出现边界清晰的“热点”，在示踪剂给药后持续240分钟。定量分析，从示踪剂给药后10分钟（闭塞后130分钟）开始，LCx/左前降支（LAD）计数比值显著增加，并持续至示踪剂给药后240分钟。在（99m）锝 - 葡糖醛酸注射后240分钟，LAD的示踪剂滞留率为12.0±0.9%，LCx热点区域为39.0±4.1%（p<0.05）。TTC测定的梗死面积与（99m）锝 - 葡糖醛酸测定结果的相关系数为0.90。

结论

在梗死仅伴有部分轻度冠状动脉再灌注的情况下，与完全再灌注情况相比，（99m）锝 - 葡糖醛酸的心肌摄取延迟且强度较低。然而，通过定性的体内成像仍可在犬中可靠地检测到梗死，并且观察到定量参数有显著异常。因此，即使在仅存在轻度冠状动脉再灌注的情况下，（99m）锝 - 葡糖醛酸成像对于急性心肌梗死的临床检测和相对面积测定可能也是有用的。