Correlation of Pancreatic Iron Overload Measured by T2*-Weighted Magnetic Resonance Imaging in Diabetic Patients with<b>β</b>-Thalassemia Major

Abstract

Diabetes mellitus (DM) is one of the potential complications in patients with transfusion-dependent β-thalassemia major (β-TM). In this case-controlled study, we examined the pancreatic iron levels in outpatients with β-TM. In this study, cases of patients with β-TM and DM were gender- and age-matched with control subjects, who were non-diabetic and had normal blood glucose on standard oral glucose tolerance (OGTT) tests. One of four diagnoses [normal, pre-diabetes, impaired glucose tolerance (IGT), DM] was made according to the American Diabetes Association (ADA) criteria. The T2*-weighted magnetic resonance imaging (T2*-weighted MRI) of the heart, liver, and pancreas was performed using a 1.5 Tesla scanner. The study enrolled 26 diabetic cases, 17 non-diabetic cases, and eight cases of IGT or pre-diabetes cases. The severity of pancreatic and cardiac iron siderosis was significantly different between the groups. We found a statistically significant difference at 5.6 ms in the T2*-weighted MRI values for the pancreas between patients with normal vs. abnormal glucose metabolism [p < 0.009; odds ratio (OR): 11.2; 95% confidence interval (95% CI): 1.32-94.4)]. The receiver operating characteristic (ROC) curve for the 5.6 ms cutoff led to an area under the curve (AUC) of 0.69 (95% CI: 55.0-84.0; p < 0.02), with sensitivity and specificity of 94.0 and 42.0%, respectively. There was a moderate positive correlation between pancreatic and cardiac T2*-weighted MRI (r = 0.4; p < 0.001), and a weak correlation between the pancreas and the liver (r = 0.38; p < 0.005). To conclude, we have introduced a cutoff of 5.6 ms on T2*-weighted MRI of the pancreas for prediction of abnormal glucose metabolism in β-TM patients.