Assessment of iron stores in children with transfusion siderosis by biomagnetic liver susceptometry

Abstract

To investigate the applicability of noninvasive Superconducting Quantum Interference Device (SQUID) biomagnetic liver susceptometry and its limitations in thalassemic children , 23 patients with-thalassemia major and other iron loading anemias (age: 4-16 years) and 16 age-related normal children were studied. Liver iron concentrations ranged from 600 to 11,000 µg/g liver for thalassemic patients and from 60 to 340 µg/g liver for normal patients. Measuring the respective organ volumes by sonography, liver and spleen iron stores, accounting for 80% of total body iron stores, were estimated. Nonliver contributions from the lung or intestine to the measured SQUID signals in the small-sized patients were not observed. Moreover, livers in thalassemia were found to be enlarged by 18% per 1,000 µg/g (r = 0.75, P < 10 −3). Serum ferritin values correlate significantly with iron stores (r = 0.64, P < 10 −3), but predict iron stores only within large error intervals of 4,000 µg/g liver. Analyzing the experimental data from biomagnetometry and from related transfusion and chelation treatment data within the framework of a two-compartment model, we were able to derive additional information on total body iron elimination and chelation therapy efficacy. The exponential decline of iron stores allows forecast of steady-state conditions of the final iron load for a particular transfusion and chelation therapy regi-men. Am. J. Hematol. 60:289-299, 1999.

Congenital dyserythropoietic anemia type II: epidemiology, clinical appearance, and prognosis based on long-term observation

“…Iron depletion has to be started at the latest when ferritin approaches a level of 1000 g/mL (1000 ng/mL). Since data correlating serum ferritin values to tissue iron are not available in CDA, prospective studies using noninvasive techniques of liver iron determination 53 are required to formulate more exact recommendations. The main utility of splenectomy is abrogation of transfusion requirements in more severe cases and increase of the hemoglobin concentration to render regular phlebotomy possible.…”

Early detection of cardiac involvement in thalassemia: From bench to bedside perspective

“…Therefore, a significantly reduced HRV could be an early indicator of preclinical stage of heart disease in TM group. Nevertheless, the evidence of HRV in TM patients has not been extensively [85,86] Inexpensive Nonspecific for cardiac iron Altered by many conditions [14] Echocardiogram Easy and available Late indicator of cardiac involvement [21,23] Inexpensive Liver biopsy…”

Noninvasive measurement of iron: report of an NIDDK workshop

“…These instruments have now been used in studies of thousands of patients with iron overload. 6,26,[28][29][30][31][32] At present, biomagnetic susceptometry provides the only noninvasive method for measurement of tissue iron stores that has been calibrated, validated, and used in clinical studies, but the complexity, cost and technical demands of the liquid-helium-cooled superconducting instruments required at present have restricted clinical access to the method. New approaches to the measurement of magnetic susceptibility are under investigation.…”