Liver Iron Quantification with MR Imaging: A Primer for Radiologists
Liver Iron Quantification with MR Imaging: A Primer for Radiologists
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DOI：
10.1148/rg.2018170079
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发表时间：
2018-03-01
期刊：
影响因子：
5.5
通讯作者：
Tang, An
中科院分区：
文献类型：
--
作者：
Labranche, Roxanne;Gilbert, Guillaume;Tang, An
铁超载是一种全身性疾病，可以是原发性（遗传性）或继发性（外源性铁给药）。原发性铁超负荷最常与遗传性血色素沉着症相关，继发性铁超负荷与无效红细胞生成（主要由13-重型地中海贫血和镰状细胞病引起）相关，需要长期输血治疗，导致输血性含铁血黄素沉着症。铁超载可能导致肝硬化和肝细胞癌，除了心脏和内分泌并发症。肝脏是主要的铁储存器官之一，也是最先表现出铁过载的器官。因此，检测和定量肝脏铁过载对于启动治疗和预防并发症至关重要。肝活检是检测和定量肝脏铁含量的历史参考标准。磁共振（MR）成像现在常用于肝脏铁定量，包括评估分布、检测、分级和监测铁过载的治疗反应。已经开发了几种用于铁定量的MR成像技术，每种技术都有优点和局限性。肝脏与肌肉信号强度比技术简单且广泛使用;然而，它假设参考组织是正常的。横向磁化（也称为R2）弛豫测定法经过验证，但由于采集时间长，易于出现呼吸运动伪影，目前仅可用于1.5 T成像，并且需要额外的成本和离线分析延迟。R2* 技术具有快速采集时间，显示了广泛的肝脏铁含量，可用于1.5-T和3.0-T成像，但需要额外的后处理软件。定量磁敏感性成像检测铁沉积的灵敏度最高，但它仍在研究中，与肝脏铁含量的相关性尚未建立。(C)RSNA，2018
Iron overload is a systemic disorder and is either primary (genetic) or secondary (exogenous iron administration). Primary iron overload is most commonly associated with hereditary hemochromatosis and secondary iron overload with ineffective erythropoiesis (predominantly caused by 13-thalassemia major and sickle cell disease) that requires long-term transfusion therapy, leading to transfusional hemosiderosis. Iron overload may lead to liver cirrhosis and hepatocellular carcinoma, in addition to cardiac and endocrine complications. The liver is one of the main iron storage organs and the first to show iron overload. Therefore, detection and quantification of liver iron overload are critical to initiate treatment and prevent complications. Liver biopsy was the historical reference standard for detection and quantification of liver iron content. Magnetic resonance (MR) imaging is now commonly used for liver iron quantification, including assessment of distribution, detection, grading, and monitoring of treatment response in iron overload. Several MR imaging techniques have been developed for iron quantification, each with advantages and limitations. The liver-to-muscle signal intensity ratio technique is simple and widely available; however, it assumes that the reference tissue is normal. Transverse magnetization (also known as R2) relaxometry is validated but is prone to respiratory motion artifacts due to a long acquisition time, is presently available only for 1.5-T imaging, and requires additional cost and delay for off-line analysis. The R2* technique has fast acquisition time, demonstrates a wide range of liver iron content, and is available for 1.5-T and 3.0-T imaging but requires additional postprocessing software. Quantitative susceptibility mapping has the highest sensitivity for detecting iron deposition; however, it is still investigational, and the correlation with liver iron content is not yet established. (C) RSNA, 2018