Ghugre Nilesh R, Enriquez Cathleen M, Gonzalez Ignacio, Nelson Marvin D, Coates Thomas D, Wood John C
Division of Cardiology, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, California 90027-0034, USA.
Magn Reson Med. 2006 Sep;56(3):681-6. doi: 10.1002/mrm.20981.
Iron-induced cardiac dysfunction is a leading cause of death in transfusion-dependent anemia. MRI relaxation rates R2(1/T2) and R2*(1/T2*) accurately predict liver iron concentration, but their ability to predict cardiac iron has been challenged by some investigators. Studies in animal models support similar R2 and R2* behavior with heart and liver iron, but human studies are lacking. To determine the relationship between MRI relaxivities and cardiac iron, regional variations in R2 and R2* were compared with iron distribution in one freshly deceased, unfixed, iron-loaded heart. R2 and R2* were proportionally related to regional iron concentrations and highly concordant with one another within the interventricular septum. A comparison of postmortem and in vitro measurements supports the notion that cardiac R2* should be assessed in the septum rather than the whole heart. These data, along with measurements from controls, provide bounds on MRI-iron calibration curves in human heart and further support the clinical use of cardiac MRI in iron-overload syndromes.
铁诱导的心脏功能障碍是依赖输血的贫血症患者的主要死因。磁共振成像（MRI）弛豫率R2（1/T2）和R2*（1/T2*）能准确预测肝脏铁浓度，但一些研究人员对其预测心脏铁含量的能力提出了质疑。动物模型研究表明心脏和肝脏铁含量的R2和R2行为相似，但缺乏人体研究。为了确定MRI弛豫率与心脏铁含量之间的关系，在一颗刚死亡的、未固定的、铁负荷心脏中，将R2和R2的区域变化与铁分布进行了比较。R2和R2与区域铁浓度成比例相关，并且在室间隔内彼此高度一致。死后测量与体外测量的比较支持了应在室间隔而非整个心脏评估心脏R2的观点。这些数据以及来自对照组的测量结果，为人体心脏MRI-铁校准曲线提供了范围，并进一步支持了心脏MRI在铁过载综合征中的临床应用。
