Department of Pediatrics and Radiology, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.
Hematology Am Soc Hematol Educ Program. 2011;2011:443-50. doi: 10.1182/asheducation-2011.1.443.
The use of magnetic resonance imaging (MRI) to estimate tissue iron was conceived in the 1980s, but has only become a practical reality in the last decade. The technique is most often used to estimate hepatic and cardiac iron in patients with transfusional siderosis and has largely replaced liver biopsy for liver iron quantification. However, the ability of MRI to quantify extrahepatic iron has had a greater impact on patient care and on our understanding of iron overload pathophysiology. Iron cardiomyopathy used to be the leading cause of death in thalassemia major, but is now relatively rare in centers with regular MRI screening of cardiac iron, through earlier recognition of cardiac iron loading. Longitudinal MRI studies have demonstrated differential kinetics of uptake and clearance among the difference organs of the body. Although elevated serum ferritin and liver iron concentration (LIC) increase the risk of cardiac and endocrine toxicities, some patients unequivocally develop extrahepatic iron deposition and toxicity despite having low total body iron stores. These observations, coupled with the advent of increasing options for iron chelation therapy, are allowing clinicians to more appropriately tailor chelation therapy to individual patient needs, producing greater efficacy with fewer toxicities. Future frontiers in MRI monitoring include improved prevention of endocrine toxicities, particularly hypogonadotropic hypogonadism and diabetes.
磁共振成像（MRI）用于估计组织铁的应用始于 20 世纪 80 年代，但直到过去十年才成为现实。该技术最常用于估计输血性血色素沉着症患者的肝脏和心脏铁，并在很大程度上取代了肝脏活检进行肝脏铁定量。然而，MRI 定量肝外铁的能力对患者的护理和我们对铁过载病理生理学的理解产生了更大的影响。铁心肌病曾经是地中海贫血症的主要死亡原因，但在常规进行心脏铁磁共振筛查的中心，由于更早地认识到心脏铁负荷，现在相对较为罕见。纵向 MRI 研究表明，不同器官之间的摄取和清除具有不同的动力学。尽管血清铁蛋白和肝脏铁浓度（LIC）升高会增加心脏和内分泌毒性的风险，但一些患者尽管总铁储存量低，仍会明确出现肝外铁沉积和毒性。这些观察结果，再加上铁螯合治疗选择的增加，使临床医生能够根据患者的个体需求更恰当地调整螯合治疗，从而在降低毒性的情况下获得更高的疗效。MRI 监测的未来前沿包括更好地预防内分泌毒性，特别是性腺功能减退性性腺功能减退和糖尿病。
