Monitoring of liver glycogen synthesis in diabetic patients using carbon-13 MR spectroscopy

To investigate the relationship between liver glucose, glycogen, and plasma glucose in diabetic patients, in vivo liver carbon-13 magnetic resonance spectroscopy ((13)C MRS) with a clinical 3.0T MR system was performed. Subjects were healthy male volunteers (n = 5) and male type-2 diabetic patients (n = 5). Pre- and during oral glucose tolerance tests (OGTT), (13)C MR spectra without proton decoupling were acquired in a monitoring period of over 6 h, and in total seven spectra were obtained from each subject. For OGTT, 75g of glucose, including 5g of [1-(13)C]glucose, was administered. The MR signals of liver [1-(13)C]glucose and glycogen were detected and their time-course changes were assessed in comparison with the plasma data obtained at screening. The correlations between the fasting plasma glucose level and liver glycogen/glucose rate (Spearman: rho = -0.68, p < 0.05, n = 10) and the fasting plasma glucose level and liver glycogen peak/fasting rate (Spearman: rho = -0.67, p < 0.05, n = 10) indicated that 13C MRS can perform non-invasive measurement of glycogen storage/degradation ability in the liver individually and can assist in tailor-made therapy for diabetes. In conclusion, (13)C MRS has a potential to become a powerful tool in diagnosing diabetes multilaterally. (C) 2008 Elsevier Ireland Ltd. All rights reserved.