Room Temp Susceptometry For Hepatic Iron Measurement

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.