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This review provides an overview of the current state of the art of magnetic resonance spectroscopy (MRS) in in vivo investigations of diffuse liver disease. So far, MRS of the human liver in vivo has mainly been used as a research tool rather than a clinical tool. The liver is particularly suitable for static and dynamic metabolic studies due to its high metabolic activity. Furthermore, its relatively superficial position allows excellent MRS localization, while its large volume allows detection of signals with relatively low intensity. This review describes the application of MRS to study the metabolic consequences of different conditions including diffuse and chronic liver diseases, congenital diseases, diabetes, and the presence of a distant malignancy on hepatic metabolism. In addition, future prospects of MRS are discussed. It is anticipated that future technical developments such as clinical MRS magnets with higher field strength (3 T) and improved delineation of multi-component signals such as phosphomonoester and phosphodiester using proton decoupling, especially if combined with price reductions for stable isotope tracers, will lead to intensified research into metabolic syndrome, cardiovascular disease, hepato-biliary diseases, as well as non-metastatic liver metabolism in patients with a distant malignant tumor.

Altered energy status has been reported in the liver of tumour-bearing animals, but data on energy status in humans are scarce. Therefore, bioenergetics in tumour-free liver of lung cancer patients were monitored using 31P magnetic resonance spectroscopy (MRS) with infusion of L-alanine as a gluconeogenic challenge.Twenty-one overnight-fasted lung cancer patients without liver metastases, with (CaWL) or without weight loss (CaWS), and 12 healthy control subjects (C) were studied. Hepatic energy status was monitored before and during an i.v. L-alanine infusion of 1.4-2.8 mmol/kg + 2.8 mmol x kg(-1) x h(-1) for 90 min by 31p MR spectroscopy.Baseline levels of ATP in WL lung cancer patients, expressed relative to total MR-detectable phosphate, were reduced (CaWL, 9.5+/-0.9% vs. CaWS, 12.6+/-0.8% and C, 12.4+/-0.8%; p0.05) and inversely correlated with the degree of weight loss in lung cancer patients (r=-0.46, p=0.03). Pi/ATP ratios were increased (p0.05), indicating reduced liver phosphorylation status. During L-alanine infusion, ATP levels decreased in all groups (p0.05); in CaWL, ATP levels were lower at all time-points between 0-90 min as compared to both CaWS and C (p0.05). Pi/ATP ratios were significantly higher after 70-90 min of L-alanine infusion in CaWL compared to CaWS and C (p0.05).Hepatic ATP and phosphorylation status are reduced in WL lung cancer patients, in contrast to WS patients and healthy subjects, and continue to decrease during infusion of a gluconeogenic substrate, suggesting impaired energy regenerating capacity in these patients.

Stable-isotope tracers were used to assess whether levels of phosphomonoesters (PME) and phosphodiesters (PDE) in the livers of lung cancer patients, as observed by P-31 magnetic resonance (MR) spectroscopy, reflect elevated whole-body glucose turnover and gluconeogenesis from alanine. Patients with advanced non-small-cell lung cancer without liver metastases (n = 24;weight loss 0-24%) and healthy control subjects (n = 13) were stud led after an overnight fast. P-31 MR spectra of the liver in vivo were obtained, and glucose turnover and gluconeogenesis from alanine were determined simultaneously using primed-constant infusions of [6,6-H-2(2)]glucose and [3-C-13]alanine. Liver PME concentrations were 6% higher in lung cancer patients compared with controls (not significant); PME levels in patients with greater than or equal to 5% weight loss were significantly higher than in patients with