We sought to estimate iron content in human siderotic livers from degree of frequency dependent attenuation (FDA) and level
of echo intensity. FDA values were measured by the spectral-shift zero-crossing method. Echo levels were determined by
subtracting echo intensity of a standard graphite-agar phantom from that of a liver sample represented by an echo-intensity
histogram. First, we used a 3.5 MHz convex transducer to measure FDA values of livers in vivo in patients with hematologic
diseases that are often associated with iron deposition in that organ. FDA values were higher in patients with aplastic anemia,
leukemia, and myelodysplastic sysndrome than in patients with idiopathic thrombocytopenia and hereditary spherocytosis.
Second, we used a 7.5 MHz annular array transducer to measure FDA values and echo levels of sectioned livers obtained from
patients who had died of similar hematologic disorders and other diseases. Degree of iron deposition in sectioned livers was
graded by microscopy, and iron content was quantitated according to the method of Foy. FDA values correlated closely with
iron content as well as with histologic grade. Echo level, on the other hand, had no correlation with iron content. We conclude
that FDA can be used to estimate hepatic iron content noninvasively when echo level is normal.