Non-invasive investigation of parenchymal liver disease using 31P NMR spectroscopy

Four 31P NMR spectroscopy parameters were measured non-invasively in the liver of 11 healthy pigs and 9 pigs with CCl4-induced liver disease: (i) absolute molar concentration of phosphorous metabolites; (ii) pH based on the chemical shift of the P(i) peak; (iii) T1 of the peaks in the 31P NMR spectrum; and (iv) changes in ATP, P1 and phosphomonoester after fructose administration. Liver disease was verified by histology and blood chemistry. The concentration of ATP decreased from 3.0(2.8-3.1) to 2.0(2.0-2.4) mM (median and quartiles) when liver disease was induced (p < 0.05). The concentration of phosphodiesters (PDEs) decreased from 14.8(11.4-19.5) to 8.7(7.4-11.6) mM (p < 0.05). pH increased by 0.1 unit. T1 relaxation times for the gamma-, alpha- and beta-ATP peaks increased from 320(249-471) to 577(506-638) ms (p < 0.01), from 765(611-786) to 906(820-1058) ms (p < 0.05) and from 402(327-509) to 579(543-743) ms (p < 0.01), respectively, while T1 for the PDE peak decreased from 2204(1909-2404) to 1758(1502-1894) ms (p < 0.05). In the healthy animals injection of fructose was followed by a reduction of ATP (beta-ATP). In diseased livers this reduction was significantly smaller. In conclusion, it was possible non-invasively to show differences between healthy and diseased livers in all NMR parameters evaluated. This means that 31P NMR spectroscopy may have a potential as a non-invasive diagnostic method for studying liver disease.