Room Temp Susceptometry For Hepatic Iron Measurement

铁超载可能在许多不同的器官中发展，导致显著的发病率和死亡率。通过静脉采血或螯合来消耗铁可以调动体内多余的铁储存并改善预后。因此，铁超载的检测和定量具有重要的临床意义。肝脏是体内铁的主要储存部位，肝脏铁负荷的大小被认为反映了体内铁的储存情况。目前，生化测定肝铁浓度(HIC)被认为是临床上评价铁超载最敏感的方法。然而，这种方法有很大的局限性，因为需要有创的肝脏活检程序，以及由于HIC的肝内变异性而产生的采样误差。 针刺肝活检测量的这些局限性要求开发替代的、非侵入性的和更可靠的HIC测量方法。这项研究将评估一种新的、低成本的便携式设备，用于非侵入性地测量肝脏中的铁浓度。新仪器是一种基于简单的常温磁性传感器的磁感应仪。在之前的测试中，新磁感仪的肝脏铁值与现有的基于液氦冷却超导传感器的“鱿鱼”磁感仪的结果有很好的相关性(r=0.98)，尽管没有与组织样本中的生化铁浓度进行直接比较。这项横断面队列研究的目标是通过研究与遗传性血色素沉着症、丙型肝炎或非酒精性脂肪性肝炎相关的铁负荷过高的患者，验证室温磁感仪作为临床工具的有效性。从肝活检标本测量的生化铁将与从同一肝叶获得的比色值进行比较。这些患者群体将测试室温磁感仪在测量大范围HIC患者的肝铁含量方面的实用性，以及由于纤维化程度和肝硬变程度而导致铁分布的变异性。

Iron overload may develop in a number of different organs, leading to significant morbidity and mortality. Iron depletion by phlebotomy or chelation can mobilize excess body iron stores and improve outcomes. Therefore, detection and quantitation of iron overload is of vital clinical importance. The liver is the primary storage site for iron in the body and the degree of hepatic iron loading is thought to reflect body iron stores. At present, biochemical measurement of hepatic iron concentration (HIC) is considered the most sensitive method for clinical assessment of iron overload. However, this method has significant limitations because of the need for an invasive liver biopsy procedure and sampling error due to intra-hepatic variability in HIC. These limitations of needle liver biopsy measurements have necessitated the development of alternative, non-invasive and more reliable methods for HIC measurement. This study will assess a new, low-cost, portable device for noninvasively measuring iron concentrations in the liver. The new instrument, is a magnetic susceptometer based on simple, room-temperature magnetic sensors. In previous tests, liver iron values from the new susceptometer correlated well (r=0.98) with those from an existing "SQUID" susceptometer based on superconducting sensors cooled by liquid helium, although there was no direct comparison with biochemical iron concentrations from tissue samples. The goal of this cross-sectional, cohort study, is to validate the room temperature susceptometer as a clinical tool, by studying patients with iron overload associated with hereditary hemochromatosis, hepatitis C infection or nonalcoholic steatohepatitis. Biochemical iron measurements from a liver biopsy specimen will be compared to the suseptometer values obtained from the same lobe of the liver. These patient populations will test the utility of the room temperature susceptometer in measuring liver iron in patients with a wide range of HIC and variability of iron distribution due to degree of fibrosis and cirrhosis.