Breuckmann Frank, Nassenstein Kai, Bucher Christina, Konietzka Ina, Kaiser Gernot, Konorza Thomas, Naber Christoph, Skyschally Andreas, Gres Petra, Heusch Gerd, Erbel Raimund, Barkhausen Jörg
Department of Cardiology, West German Heart Center, Essen, Germany.
JACC Cardiovasc Imaging. 2009 Feb;2(2):121-30. doi: 10.1016/j.jcmg.2008.10.011.
Our study aimed to detect the morphological und functional effects of coronary microembolization (ME) in vivo by cardiac magnetic resonance (CMR) imaging in an established experimental animal model.
Post-mortem morphological alterations of coronary ME include perifocal inflammatory edema and focal microinfarcts. Clinically, the detection of ME after successful coronary interventions identifies a population with a worse long-term prognosis.
In 18 minipigs, ME was performed by intracoronary infusion of microspheres followed by repetitive in vivo imaging on a 1.5-T MR system from 30 min to 8 h after ME. Additionally, corresponding ex vivo CMR imaging and histomorphology were performed.
Cine CMR imaging demonstrated a time-dependent increase of wall motion abnormalities from 9 of 18 animals after 30 min to all animals after 8 h (0.5 h, 50%; 2 h, 78%; 4 h, 75%; 8 h, 100%). Whereas T2 images were negative 30 min after ME, 4 of 18 animals showed myocardial edema at follow-up (0.5 h, 0%; 2 h, 6%; 4 h, 25%; 8 h, 17%). In vivo late gadolinium enhancement (LGE) was observed in none of the animals after 30 min, but in 33%, 50%, and 83% of animals at 2 h, 4 h, and 8 h, respectively, after ME. Ex vivo CMR imaging showed patchy areas of LGE in all but 1 animal (2 h, 83%; 4 h, 100%; 8 h, 100%). A significant correlation was seen between the maximum troponin I level and LGE in vivo (r = 0.63) and the spatial extent of ex vivo LGE (r = 0.76).
Our results show that in vivo contrast-enhanced CMR imaging allows us to detect functional and structural myocardial changes after ME with a high sensitivity. Ex vivo, the pattern of LGE of high-resolution, contrast-enhanced CMR imaging is different from the well-known pattern of LGE in compact myocardial damage. Thus, improvements in spatial resolution are thought to be necessary to improve its ability to visualize ME-induced structural alterations even in vivo.
我们的研究旨在通过心脏磁共振（CMR）成像，在一个已建立的实验动物模型中检测体内冠状动脉微栓塞（ME）的形态学和功能学效应。
冠状动脉ME的尸检形态学改变包括灶周炎性水肿和局灶性微梗死。临床上，在成功的冠状动脉介入治疗后检测到ME可识别出长期预后较差的人群。
在18只小型猪中，通过冠状动脉内注入微球进行ME，然后在ME后30分钟至8小时内，在1.5-T MR系统上进行重复的体内成像。此外，还进行了相应的离体CMR成像和组织形态学检查。
电影CMR成像显示壁运动异常呈时间依赖性增加，从ME后30分钟时18只动物中的9只增加到8小时时的所有动物（0.5小时，50%；2小时，78%；4小时，75%；8小时，100%）。ME后30分钟时T2图像为阴性，但随访时18只动物中有4只出现心肌水肿（0.5小时，0%；2小时，6%；4小时，25%；8小时，17%）。ME后30分钟时没有动物观察到体内延迟钆增强（LGE），但分别在ME后2小时、4小时和8小时时，有33%、50%和83%的动物出现LGE。离体CMR成像显示，除1只动物外，所有动物均有散在LGE区域（2小时，83%；4小时，100%；8小时100%）体外LGE的空间范围之间存在显著相关性（r = 0.76）。
我们的结果表明，体内对比增强CMR成像使我们能够高灵敏度地检测ME后心肌的功能和结构变化。在体外，高分辨率对比增强CMR成像的LGE模式与致密心肌损伤中众所周知的LGE模式不同。因此，即使在体内，也认为有必要提高空间分辨率，以改善其可视化ME诱导的结构改变的能力。
