Pancreatic iron stores assessed by magnetic resonance imaging (MRI) in beta thalassemic patients.

PURPOSE: To assess the correlation between MRI findings of the pancreas with those of the heart and liver in patients with beta thalassemia; to compare the pancreas T2* MRI results with glucose and ferritin levels and labile plasma iron (LPI).

MATERIALS AND METHODS: We retrospectively evaluated chronically transfused patients, testing glucose with enzymatic tests, serum ferritin with chemiluminescence, LPI with cellular fluorescence, and T2* MRI to assess iron content in the heart, liver, and pancreas. MRI results were compared with one another and with serum glucose, ferritin, and LPI. Liver iron concentration (LIC) was determined in 11 patients' liver biopsies by atomic absorption spectrometry.

RESULTS: 289 MRI studies were available from 115 patients during the period studied. 9.4% of patients had overt diabetes and an additional 16% of patients had impaired fasting glucose. Both pancreatic and cardiac R2* had predictive power (p<0.0001) for identifying diabetes. Cardiac and pancreatic R2* were modestly correlated with one another (r(2) = 0.20, p<0.0001). Both were weakly correlated with LIC (r(2) = 0.09, p<0.0001 for both) and serum ferritin (r(2) = 0.14, p<0.0001 and r(2) = 0.03, p<0.02, respectively). None of the three served as a screening tool for single observations. There is a strong log-log, or power-law, relationship between ratio of signal intensity (SIR) values and pancreas R2* with an r(2) of 0.91.

CONCLUSIONS: Pancreatic iron overload can be assessed by MRI, but siderosis in other organs did not correlate significantly with pancreatic hemosiderosis.