INSERM U841, IMRB, Faculté de médecine, Université Paris 12 et Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France.
Eur Radiol. 2010 May;20(5):1214-20. doi: 10.1007/s00330-009-1660-7. Epub 2009 Nov 21.
Contrast-enhanced cardiac magnetic resonance (CMR) for infarct sizing has been validated in large animals, but studies and follow-up are restricted. We sought to (1) validate CMR for assessment of myocardial area at risk (MAR) and infarct size (IS) in a rabbit model of reperfused myocardial infarction (MI); (2) analyse the relation between ischaemic substrates and subsequent left ventricular (LV) remodelling.
Experimental reperfused acute MI was induced in 16 rabbits. Ten animals underwent cross-registered cine and contrast-enhanced CMR and histopathology at day 3 for assessment of MAR and IS (group 1). The remaining six rabbits underwent serial CMR for the study of LV remodelling (group 2).
In group 1, mean IS was 12.7 +/- 6.4% and 12.7 +/- 6.9% of total LV myocardial mass on CMR (late-enhancement technique) and histopathology (P = 0.52; r = 0.93). No significant difference occurred between CMR and histopathology for the calculation of MAR and IS/MAR ratio (P = 0.18 and P = 0.17), whereas correlations were strong (r = 0.92 and r = 0.95). In group 2, mean LV end-diastolic, end-systolic volumes and LV mass were significantly increased at 3 weeks compared with measurements at day 3 (P < 0.01). Significant correlations between initial IS and the increase in LV end-diastolic volume (r = 0.66) and the increase in LV mass (r = 0.48) were observed, as well as correlations between initial MAR and the increase in LV end-diastolic volume (r = 0.70) and the increase in LV mass (r = 0.37).
Comprehensive CMR provides accurate assessment of IS and MAR in reperfused rabbit MI. Infarct size is closely related to LV remodelling. Through the infarct size/MAR ratio, this approach has great potential for assessing interventions aimed at cardioprotection.
对比增强心脏磁共振（CMR）在大型动物中的梗死灶大小验证已得到验证，但研究和随访受到限制。我们试图（1）在兔再灌注心肌梗死（MI）模型中验证 CMR 评估心肌危险区（MAR）和梗死面积（IS）；（2）分析缺血底物与随后左心室（LV）重构之间的关系。
在 16 只兔子中诱导实验性再灌注急性 MI。10 只动物接受了电影和对比增强 CMR 的交叉注册，并在第 3 天进行了病理检查，以评估 MAR 和 IS（第 1 组）。其余 6 只兔子接受了连续 CMR 检查，以研究 LV 重构（第 2 组）。
在第 1 组中，CMR（延迟增强技术）和组织病理学上的平均 IS 分别为 12.7±6.4%和 12.7±6.9%的总 LV 心肌质量（P=0.52；r=0.93）。CMR 和组织病理学计算 MAR 和 IS/MAR 比值之间没有显著差异（P=0.18 和 P=0.17），而相关性很强（r=0.92 和 r=0.95）。在第 2 组中，与第 3 天的测量值相比，3 周时 LV 舒张末期、收缩末期容积和 LV 质量显著增加（P<0.01）。观察到初始 IS 与 LV 舒张末期容积增加（r=0.66）和 LV 质量增加（r=0.48）之间存在显著相关性，以及初始 MAR 与 LV 舒张末期容积增加（r=0.70）和 LV 质量增加（r=0.37）之间的相关性。
综合 CMR 可准确评估兔再灌注 MI 的 IS 和 MAR。梗死面积与 LV 重构密切相关。通过梗死面积/MAR 比值，这种方法在评估旨在保护心脏的干预措施方面具有很大的潜力。
