Muellerleile K, Barmeyer A, Groth M, Lund G K
Center for Cardiology and Cardiovascular Surgery, University Medical Center Hamburg-Eppendorf Hamburg, Germany.
Minerva Cardioangiol. 2008 Apr;56(2):237-49.
Assessment of myocardial viability aims at differentiating between viable and non-viable myocardium. The proof of dysfunctional but viable myocardium is crucial to predict outcome of revascularization after acute (AMI) and chronic myocardial infarction (CMI). Cardiac magnetic resonance imaging (CMRI) offers different options to detect viable myocardium: Measurements of end-diastolic wall thickness by cine-CMRI can be used to depict chronically scarred myocardium, but fails to detect acute myocardial necrosis. Low-dose dobutamine stimulation (LDDS) cine-CMRI analyses the contractile reserve of dysfunctional but viable myocardium under pharmacologic stimulus to identify viable myocardium in AMI and CMI with high specificity. Sensitivity of LDDS cine-CMRI is superior to LDDS echocardiography but reduced in patients with severely impaired left ventricular (LV) function. The delayed-enhancement (DE) technique directly visualises non-viable myocardium due to an altered contrast-media distribution in necrotic and fibrotic tissue. DE-CMRI identifies non-viable myocardium with high spatial resolution independently from LV function. The transmural extent of contrast enhancement in DE-CMRI is used to predict functional recovery after revascularization in AMI and CMI. Furthermore, the amount and pattern of contrast enhancement in DE-CMRI provide important prognostic information in both entities. Recent studies demonstrated the superiority of DE-CMRI compared to single photon emission tomography (SPECT) and positron emission tomography (PET) to assess myocardial viability. Therefore, DE-CMRI is currently recognised as the standard of reference for assessment of myocardial viability. The technical background, clinical application and accuracy of the different CMRI techniques to assess myocardial viability in AMI and CMI are discussed in this work.
心肌活力评估旨在区分存活心肌和无活力心肌。证明功能失调但存活的心肌对于预测急性心肌梗死（AMI）和慢性心肌梗死（CMI）后血运重建的结果至关重要。心脏磁共振成像（CMRI）提供了多种检测存活心肌的方法：电影CMRI测量舒张末期室壁厚度可用于描绘慢性瘢痕化心肌，但无法检测急性心肌坏死。低剂量多巴酚丁胺刺激（LDDS）电影CMRI分析功能失调但存活心肌在药物刺激下的收缩储备，以高特异性识别AMI和CMI中的存活心肌。LDDS电影CMRI的敏感性优于LDDS超声心动图，但在左心室（LV）功能严重受损的患者中会降低。延迟强化（DE）技术可直接显示由于坏死和纤维化组织中造影剂分布改变而导致的无活力心肌。DE-CMRI可独立于LV功能以高空间分辨率识别无活力心肌。DE-CMRI中造影剂强化的透壁范围用于预测AMI和CMI血运重建后的功能恢复。此外，DE-CMRI中造影剂强化的量和模式在这两种情况下都提供了重要的预后信息。最近的研究表明，与单光子发射断层扫描（SPECT）和正电子发射断层扫描（PET）相比，DE-CMRI在评估心肌活力方面具有优势。因此，DE-CMRI目前被认为是评估心肌活力的参考标准。本文讨论了不同CMRI技术评估AMI和CMI中心肌活力的技术背景、临床应用和准确性。
