纽约（路透健康）11月21日——据《美国心脏病学会杂志》11月7日刊报道，氟脱氧葡萄糖PET成像（FDG-PET）可用于非侵入性识别患者颈动脉斑块的炎症程度。
来自麻萨诸塞州综合医院和波士顿哈佛大学医学院的Ahmed Tawakol博士对路透健康版表示，“PET成像可以反映斑块的生物学特征，而斑块的生物学特征可被证实是比狭窄更有力的风险预测因素。我认为斑块的PET成像将成为评估治疗动脉粥样硬化疾病方法的有效手段。”
Tawakol 博士和他的同事们为了确定能否无创检测活体内颈动脉炎症，他们对17位严重颈动脉狭窄已经准备行颈动脉内膜剥离术的成年患者进行了FDG-PET。
结果发现，PET信号与动脉内膜切除术时去除的斑块内巨噬细胞染色有显著相关性。FDG摄取和平均炎症程度的相关性更加密切（由氯丹染色的平均百分比测量）。相反，FDG摄取和斑块的厚度或斑块的面积无显著相关性。
研究者解释道，“当前这项研究的结果表明，颈动脉PET 研究通过识别炎症斑块（炎症斑块可能伴随着更高的临床事件风险），可帮助对那些颈动脉狭窄程度轻或无症状性损害的患者进行危险分层。”
Tawakol博士说：“今后还需进行有关颈动脉斑块自然发展过程的研究以评价斑块成像的临床相关性，另外，我们也在设计几项药物干预研究。”
相关背景知识：
1. 什么是PET？
PET/CT全称正电子发射断层显像/X线计算机体层成像，是一种无创性的分子显像技术，将极其微量的正电子示踪剂注射到人体内，利用体外探测仪器（PET）探测这些正电子核素在人体全身脏器的分布情况，可在分子水平高灵敏显示人体全身主要器官以及大脑、心脏的生理、病理功能和结构的改变，同时应用CT技术进行辅助诊断和精确定位，同步获得人体结构解剖和生理代谢功能情况的信息。
2. 非侵入性成像：使未来看动脉粥样硬化斑快更清楚
在第十五届世界心脏病大会（WCC）和欧洲心脏病学会年会（ESC）上，Gerald M Pohost 和Marlon G Ramilo 教授报告了在心血管领域非侵入性成像技术的未来价值。
非侵入性影象通过对心肌灌注、代谢及活力的评估进而对冠状动脉病理和冠状动脉血管床作出综合评价。重要的问题是非侵入性影象能否被用于评价动脉粥样硬化斑块、特别是易损斑快。二维超声、多排计算机断层摄影（MSCT）、心血管磁共振（CMR）、正电子发射计算机断层扫描（PET）全部被列入这一领域的研究之中。
PET通过巨嗜细胞和其它高代谢细胞的代谢活性来评价炎症。18F- FDG（氟脱氧葡萄糖）PET对于富含巨嗜细胞的易损斑块的选择性观察是非常实用的。18F- FDG 在斑块中的定位已在人的颈动脉、主动脉、和其它主要动脉得到证实。然而，18F- FDG 对于高脂质血管的影象太宽，而对易损斑块并不特异。99mTc 标记的膜联蛋白Ⅴ，一种细胞凋亡的标记物，已提示在不稳定损伤中由于存在大量凋亡细胞而可以对其作出评估。
PET identifies inflammation severity in carotid plaques
11/21/2006
By: Reuters Health
http://www.auntminnie.com/index.asp?Sec=sup&Sub=mol&Pag=dis&ItemId=73605
NEW YORK (Reuters Health), Nov 21 - PET imaging with fluorodeoxyglucose (FDG-PET) can be used to identify noninvasively the degree of inflammation in carotid plaques in patients, according to a report in the November 7th issue of the Journal of the American College of Cardiology.
"Plaque biology can be imaged using PET and may prove to be a stronger predictor of risk than stenosis," Dr. Ahmed Tawakol from Massachusetts General Hospital and Harvard Medical School, Boston, told Reuters Health. "I believe that PET imaging of plaque may prove to be a remarkably powerful way of evaluating the effect of new therapies targeting atherosclerotic diseases."
Dr. Tawakol and colleagues investigated whether inflammation in human carotid arteries could be measured noninvasively in vivo using FDG-PET in 17 adult patients with severe carotid artery stenosis already scheduled to undergo carotid endarterectomy.
The PET signal correlated significantly with macrophage staining in the plaques removed at the time of endarterectomy, the team found.
The correlation was even stronger between FDG uptake and mean inflammation (as measured by mean percentage of CD68 staining), the results indicate.
In contrast, FDG uptake did not correlate significantly with plaque thickness or plaque area, the researchers note.
"The findings of the present study suggest that PET studies of the carotid arteries could aid in the risk stratification of patients with less stenotic or asymptomatic lesions by identifying inflamed plaques that may be associated with a higher risk of a clinical event," the investigators explain.
"Natural history studies are needed to evaluate the clinical relevance of plaque imaging," Dr. Tawakol said. "We are also planning several additional pharmacological intervention studies."
By Will Boggs, M.D.
Last Updated: 2006-11-20 13:39:49 -0400 (Reuters Health)
J Am Coll Cardiol 2006;48:1818-1824.
编辑：蓝色幻想
