通过动物实验及临床研究，我们已经证明MRI可以定量心肌铁沉积，那么是否可以定量铁沉积导致的心肌纤维化？因为纤维化最终发展为心力衰竭是铁过载患者最主要的死亡原因之一。及时了解纤维化程度，加强去铁治疗，可以逆转病情。临床应用血清学指标诊断纤维化缺乏特异性，而心内膜活检具有创伤性，常规不可行。研究已证实T1-mapping和细胞外容积（ECV）技术可以定量非铁过载患者心肌弥散性纤维化。通过心肌铁过载猪模型的预实验，我们发现在铁沉积状态下ECV与病理纤维化指标--胶原容积分数（CVF）存在一定关系。由此我们推测这种方法可能可以定量心肌铁沉积导致的纤维化。本研究旨在应用T1-mapping和ECV技术，通过心肌铁过载猪模型，探讨ECV与CVF关系。从而通过MRI测定数据预测心肌纤维化程度,寻找一种定量铁沉积所致纤维化的有效、无创的方法，为临床了解铁过载患者心肌纤维化程度提供准确依据奠定基础。

We have demonstrated the feasibility of cardiac iron quantification by MRI through the iron overload animal model and clinical study. So, if we could use MRI to predict myocardial fibrosis caused by iron deposited? Cardiac complications, such as fibrosis resulted in heart failure is the major cause of death in iron overloaded patients. Iron cardiomyopathy is reversible, if intensive chelation starts in time, but diagnosis is often delayed by the unpredictability of myocardial fibrosis formation and the late development of symptoms. Myocardial fibrosis has been previously reported to correlate with serum indexes, but serum indexes lack specificity. Direct measurement of fibrosis levels by subendocardial biopsy is not practical for its invasion. Recently, T1 mapping and extracellular volume (ECV) quantification have emerged as novel methods that can detect diffuse myocardial fibrosis in non-iron overloaded patients. Through the preliminary experiment, we had found myocardial ECV was associated with pathological fibrosis index—collagen volume fraction(CVF) in the case of iron deposition. So we assume that the methold possibly could quantify myocardial fibrosis caused by iron overloaded. The aims of this study are to develop a reproducible T1 mapping and.extracellular volume for quantifying myocardial fibrosis of different cardiac iron overload pig model and explore the relationship between ECV and myocardial CVF. Furthermore, apply MRI method to assess the degree of myocardial fibrosis caused by iron deposited in iron overloaded patients. Finally developing a reliable and noninvasive techniques to measure myocardial fibrosis and lay the foundation for clinician to early diagnosis and treatment and help to reduce mortality.

铁过载患者体内过多的铁沉积在心脏可以导致心肌弥散性纤维化，最终可发展为心力衰竭。心力衰竭是铁过载患者最主要的死亡原因之一。及时了解纤维化程度，加强去铁治疗，可以逆转病情。临床应用血清学指标诊断纤维化缺乏特异性，而心内膜活检具有创伤性，常规不可行。研究已证实T1-mapping和细胞外容积（ECV ）技术可以定量非铁过载患者心肌弥散性纤维化，但尚未证实是否可以应用于铁过载患者，更缺乏动物实验作为基础。本研究通过建立铁过载所致心肌纤维化巴马猪模型，进行多回波GRE和ShMOLLI序列心脏平扫及不同时间点ShMOLLI序列钆剂增强扫描，获得T2*图像及初始和一系列增强T1-mapping图像，测量心肌T1值、T2*值，计算ECV。通过病理检查定量心肌胶原容积分数（CVF），并应用原子分光光度仪测量心肌铁浓度。本研究发现心肌ECV与CVF存在高度正相关（r=0.990，P＜0.001）。根据线性回归，可得到ECV与CVF的回归方程：Y=0.467X -0.010 （F=1139.33，P＜0.001），其中Y为CVF，X为ECV。ECV与注射铁剂总量之间高度正相关（r=0.913，P＜0.001）。CVF与注射铁剂总量之间高度正相关（r=0.932，P＜0.001）。本研究发现在铁沉积背景下ECV与CVF之间高度正相关，通过MRI测量ECV根据所得公式进而可计算CVF定量心肌纤维化。以动物实验研究为基础，给临床了解铁超负荷患者心肌纤维化情况，制定治疗方案，以及对治疗疗效的评价，提供一种无创、准确且可反复的检查方法。