Quantitative 31P magnetic resonance spectroscopy in diffuse liver disease

Sammanfattning: The studies in this thesis were delineated to evaluate the diagnostic possibilities in patients with diffuse liver disease by using phosphorus-31 MR spectroscopy and comparing the results with clinical, laboratory and histopathological findings. For this purpose in all 38 patients and 25 controls without evidence of liver disease were examined.In the first study 31P-MRS using slice selection (DRESS) was implemented to investigate the absolute concentrations of metabolites in human liver. The metabolite concentration quantification procedures included: 1. Determination of optimal depth for the in vivo measurements, 2. Mapping the detection coil characteristics, 3. Calculation of selected slice and liver volume ratios using simple segmentation procedures, and 4. Spectral analysis in the time domain. Patients with histopathologically proven diffuse liver disease (n = 9) and healthy individuals (n = 12) were examined. The patients had significantly lower concentrations of phosphodiesters (PDE) and ATP-ß compared with the control group. Constructing an anabolic charge (AC) based on absolute concentrations, [PME] / ([PME] + [PDE]), the patients had a significant larger AC than the control subjects, 0.29 vs. 0.16 (p < 0.005).In the second study the MRS technique was applied on two distinct groups of patients with diffuse chronic liver disorders, one group with steatosis and none-to-moderate inflammation (n = 13) and one group with severe fibrosis or cirrhosis (n = 16). All patients underwent liver biopsy and extensive biochemical evaluation. A control group (n = 13) was also included. Lower concentrations of PDE (p = 0.025) and a higher AC (p = 0.001) were found in the cirrhosis group compared to the control group.Using a PDE concentration of 10.5 mM as a cut-off value to discriminate between mild (stage 0-2) and advanced (stage 3-4) fibrosis the sensitivity and specificity were 81% and 69% respectively. An AC cut-off value of 0.27 showed a sensitivity of 93% and a specificity of 54%.In conclusion the results indicates that a decrease in PDE concentration is a marker of liver fibrosis and that AC is a potentially clinically useful parameter indiscriminating mild fibrosis from advanced. No significant relationship between the MRS data and the degree of steatosis or inflammation was found.