Kooi M E, Cappendijk V C, Cleutjens K B J M, Kessels A G H, Kitslaar P J E H M, Borgers M, Frederik P M, Daemen M J A P, van Engelshoven J M A
Department of Radiology, University Hospital Maastricht, Peter Debyelaan 25, 6229 HX Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands.
Circulation. 2003 May 20;107(19):2453-8. doi: 10.1161/01.CIR.0000068315.98705.CC. Epub 2003 Apr 28.
One of the features of high-risk atherosclerotic plaques is a preponderance of macrophages. Experimental studies with hyperlipidemic rabbits have shown that ultrasmall superparamagnetic particles of iron oxide (USPIOs) accumulate in plaques with a high macrophage content and that this induces magnetic resonance (MR) signal changes. The purpose of our study was to investigate whether USPIO-enhanced MRI can also be used for in vivo detection of macrophages in human plaques.
MRI was performed on 11 symptomatic patients scheduled for carotid endarterectomy before and 24 (n=11) and 72 (n=5) hours after administration of USPIOs (Sinerem) at a dose of 2.6 mg Fe/kg. Histological and electron microscopical analyses of the plaques showed USPIOs primarily in macrophages within the plaques in 10 of 11 patients. Histological analysis showed USPIOs in 27 of 36 (75%) of the ruptured and rupture-prone lesions and 1 of 14 (7%) of the stable lesions. Of the patients with USPIO uptake, signal changes in the post-USPIO MRI were observed by 2 observers in the vessel wall in 67 of 123 (54%) and 19 of 55 (35%) quadrants of the T2*-weighted MR images acquired after 24 and 72 hours, respectively. For those quadrants with changes, there was a significant signal decrease of 24% (95% CI, 33% to 15%) in regions of interest in the images acquired after 24 hours, whereas no significant signal change was found after 72 hours.
Accumulation of USPIOs in macrophages in predominantly ruptured and rupture-prone human atherosclerotic lesions caused signal decreases in the in vivo MR images.
高危动脉粥样硬化斑块的特征之一是巨噬细胞占优势。对高脂血症兔的实验研究表明，超小超顺磁性氧化铁颗粒（USPIO）在巨噬细胞含量高的斑块中蓄积，并由此引起磁共振（MR）信号改变。我们研究的目的是探讨USPIO增强磁共振成像是否也可用于体内检测人体斑块中的巨噬细胞。
对11例计划行颈动脉内膜切除术的有症状患者在给予剂量为2.6mg铁/千克的USPIO（Sinerem）之前、之后24小时（n=11）和72小时（n=5）进行磁共振成像。对斑块进行组织学和电子显微镜分析，结果显示，在11例患者中的10例中，USPIO主要存在于斑块内的巨噬细胞中。组织学分析显示，在36个破裂和易破裂病变中的27个（75%）以及14个稳定病变中的1个（7%）发现有USPIO。在摄取USPIO的患者中，2名观察者分别在24小时和72小时后获得的T2*加权磁共振图像的血管壁的123个象限中的67个（54%）和55个象限中的19个（35%）观察到USPIO磁共振成像后的信号变化。对于那些有变化的象限，在24小时后获得的图像中，感兴趣区域的信号显著降低了24%（95%CI，33%至15%），而在72小时后未发现显著的信号变化。
在主要为破裂和易破裂的人体动脉粥样硬化病变中，巨噬细胞内USPIO的蓄积导致体内磁共振图像信号降低。
