Magnetic resonance imaging of the pancreas in streptozotocin-induced diabetic rats: Gadofluorine P and Gd-DOTA

Abstract

AIM: To investigate the performance of Gadofluorine P-enhanced magnetic resonance imaging (MRI) on the diagnosis of diabetes in a streptozotocin (STZ) -induced diabetic rat model. METHODS: Fischer 344 rats were treated with STZ. Rats not treated with STZ served as controls. T1-weighted MRI was performed using a 3T scanner before and after the injection of Gd-DOTA or Gadofluorine P (6 diabetic rats, 5 controls). The normalized signal intensity (SI) and the enhancement ratio (ER) of the pancreas were measured at each time point, and the values were compared between the normal and diabetic rats using the Mann-Whitney test. In addition, the values were correlated with the mean islet number. Optimal cut-off values were calculated using a positive test based on receiver operating characteristics. Intrapancreatic Gd concentration after the injection of each contrast media was measured using laser ablation-inductively coupled plasma-mass spectrometry in a separate set of rats (4 diabetic rats, 4 controls for Gadofluorine P; 2, 2 for Gd-DOTA). RESULTS: The normalized SI and ER of the pancreas using Gd-DOTA were not significantly different between diabetic rats and controls. With Gadofluorine P, the values were significantly higher in the diabetic rats than in the control rats 30 min after injection (P < 0.05). The area under the receiver operating characteristic curve that differentiated diabetic rats from the control group was greater for Gadofluorine P than for Gd-DOTA (0.967 vs 0.667, P = 0.085). An increase in normalized SI 30 min after Gadofluorine P was correlated with a decrease in the mean number of islets (r(2) = 0.510, P = 0.014). Intra-pancreatic Gd was higher in rats with Gadofluorine P injection than Gd-DOTA injection (Gadofluorine P vs Gd-DOTA, 7.37 vs 0.00, P < 0.01). A significant difference in the concentration of intrapancreatic Gd was observed between the control and diabetic animals that were sacrificed 30 min after Gadofluorine P injection (control vs diabetic, 3.25 ng/g vs 10.55 ng/g, P < 0.05). CONCLUSION: In this STZ-induced diabetes rat model, Gadofluorine P-enhanced MRI of the pancreas showed high accuracy in the diagnosis of diabetes.