一项全球范围的调查显示，近一半的地中海贫血患者心脏铁超负荷，因此，广泛进行T2加权的CMR很有必要。研究在17届EHA大会上进行了报告。

    即使在定期接受输血及铁螯合剂治疗效果较好的地中海贫血患者中，在第一次T2加权CMR扫描中也有43%的人检查出心脏铁超负荷。研究领导者伦敦皇家Brompton医院的John-Paul Carpenter博士说。

    Carpenter博士此前的一项研究表明，英国2000-2004年间，地中海贫血的死亡率降低71%，这很大程度上是由于引进专科治疗及T2加权CMR。

    第一种测量心脏铁含量的方法

    在上世纪80年代，研究人员发现，铁过载的地中海贫血患者的MRI图像中，肝、脾、骨髓都是黑色的，进而发现，心脏中铁含量可以通过CMR测量。

    Carpenter博士此前的研究发现，心脏铁含量与T2加权CMR信号密切相关。铁含量高，T2加权信号上升速度小于10ms；信号亮度衰减迅速则是因为铁过量。T2加权信号时间低于10ms，心脏铁含量高于2.7mg/g，心力衰竭的死亡风险高；T2加权信号时间高于20ms，则心脏铁含量低于1.1mg/g，心力衰竭的死亡风险低。

    全球调查

    Carpenter博士及同事考察了世界其他使用T2加权CMR的治疗中心铁过载监测及治疗的情况。34个国际地中海贫血治疗中心参与了调查，包括美国、欧洲、中东及南亚，涉及患者3376人。

    研究人员发现，仅有42.5%的患者具有明显的心脏铁过载，大量的患者存在心脏疾病风险。在中国及南亚，25%的患者有铁过载高风险，而在澳大利亚、埃及和北美，这一比例不足15%。

    carpenter博士表示，这些数据真实的反映了地中海贫血螯合治疗现状，提示我们要继续加强临床教育以提高患者的生存质量。t2加权cmr的广泛使用可以尽早检查出患者心脏铁超负荷进行治疗，防止心脏衰竭，保证患者的生活质量，从而挽救更多的生命。

    INTERNATIONAL SURVEY OF T2* C**IOVASCULAR MAGNETIC RESONANCE IN THALASSEMIA

    Background: Beta thalassaemia major （TM） is a substantial global health issue, with over 25,000 affected children born each year. Accumulation of cardiac iron is the cause of heart failure and early death in many TM patients who depend on regular blood transfusions. Cardiovascular magnetic resonance （CMR） T2* measurement has been shown to provide an accurate, reproducible measurement of cardiac iron and this technique has now been adopted as part of routine management in many countries. A dramatic 71% decrease in deaths has been observed in the UK thalassaemia cohort since the introduction of improved chelation and the routine use of CMR T2*. Whilst cardiac T2* has a strong prognostic value in the UK cohort, little is known about the burden of cardiac iron loading, its effects or the application of CMR T2* across different geographical regions.

    Aims: To gain an understanding of the worldwide use of CMR T2* via an international survey of centres that regularly use T2* to assess its clinical application, the degree of iron loading and relation to clinical outcomes.

    Methods: A survey was undertaken in 35 worldwide centres of 3,445 patients from Europe, the Middle East, North America, South America, North Africa, Australia and Asia. Anonymised data on myocardial T2* values were **ysed in conjunction with clinical outcomes （heart failure and death）。 For the purposes of this study, cardiac failure was defined as symptoms or signs of cardiac failure associated with objective evidence of ventricular dysfunction at rest （defined as reduced left ventricular ejection fraction <56% measured by CMR）。

    Results: Of the total of 3,445 patients, overall 57.7% had no significant iron loading （T2* >20ms）， 22.5% had moderate cardiac iron （10ms < T2* ≤ 20ms） and 19.8% had severe cardiac iron （T2* ≤10ms） at baseline. The prevalence of moderate （T2* <20ms） and severe （T2* <10ms） myocardial iron loading varied significantly between regions with the lowest level being found in patients from Egypt and the highest in South-East Asia （P <0.001）。 At the time of the first scan, 107 patients （3.5%） had confirmed heart failure, the majority of whom （75.7%） had myocardial T2* <10ms, with 98.1% having T2* <20ms. During follow-up, 116 patients subsequently developed heart failure, and of these, 92.2% had T2* <10ms and 100% had a T2* of <20ms at the time of the first T2* CMR scan. There were 38 deaths during follow-up: at baseline scan, 86.4% had myocardial T2* <10ms, and 97.2% had myocardial T2* <20ms.

    Conclusion: In this well-treated cohort of TM patients from centres across the world who had access to regular transfusion, chelation and T2* CMR, a large proportion （42.3%） had moderate to severe cardiac iron loading. Cardiac T2* values <10ms were strongly associated with the development of cardiac failure and death. There were marked regional differences in the prevalence of cardiac siderosis which may reflect differences in predisposition to cardiac iron loading.