磁共振追踪标记技术识别心肌梗死后左室壁运动失调的临床应用

目的探讨磁共振Tagging成像对于诊断心肌梗死后左室室壁瘤收缩运动失调区域的临床价值。方法12例既往有典型心肌梗死病史和心电图改变,经冠状动脉造影确诊为“冠心病,左室室壁瘤”的慢性心肌梗死后患者,行心脏磁共振Tagging序列和延迟增强序列扫描对照检查。结果10例患者磁共振Tagging序列获得良好成像效果(成功率83%),能够识别出室壁收缩的三种运动形态:收缩存在、收缩消失、反常收缩。通过与延迟强化室壁节段的对照观察,我们发现有6/16个节段的收缩消失区域并未显示出心肌梗死的特征改变,室壁未见变薄或异常强化。同时我们还发现有5个节段的室壁,虽然纵向短缩率消失,而辐射向心收缩力仍然存在。结论磁共振Tagging技术能够较明确识别室壁瘤或远隔室壁节段的不同收缩状态,对于室壁瘤的外科治疗能提供重要的诊断信息。

Clinical application of MRI tagging for detection of left ventricular asynergic wall after myocardial infarction

Objective To estimate the clinical value of MRI tagging in the diagnosis of asynergic zones of left ventricular aneurysm (LVA). Methods Twelve patients presenting with formerly typical symptoms of AMI along with abnormal Q waves on ECG and diagnosed angiographically as coronary artery disease (CAD) with LVA underwent MRI examination applying tagging sequence in combination with late-delayed enhancement (LDE) evaluation to observe the morphological and functional characteristics of asynergic segments after AMI. Results MRI tagging technique can visualize distinctly three patterns of ventricular wall motion: kinetic, akinetic and dyskinetic in 10/12 patients (success rate 83%). By comparing with LDE images, in 6/16 akinetic segments, we found no signs of myocardial infarction including intramural hyper-enhancement or wall thinning, implying that these regions reflected reversibly ischemic injury (such as hibernation or stunning) which had the potential of functional recovery after surgical revascularization without the need of exclusion in the LVA repair procedure. Meanwhile, we also found that in 5 longitudinally akinetic zones, tagging can demonstrate the existence of radial contractility, showing the possibility of postoperative revitalization. Conclusion The clinical analysis of MRI tagging results can differentiate among the various conditions of regional ventricular-wall function in LVA or remote myocardium and provide more valuable information to further surgical treatment of LVA.