title: The total entropy for evaluating 31P-magnetic resonance spectra of the liver in healthy volunteers and patients with metastases.
abstract: OBJECTIVE
  The authors describe the clinical status of liver tissue with only a single numerical quantity (total entropy) derived from spectroscopic data of 31P-magnetic resonance (MR) spectra.
  
  
  METHODS
  Twenty-four patients with liver metastases and 20 volunteers were investigated with image-guided volume selective 31P-MR spectroscopy on a 1.5-T whole body scanner. From each in vivo 31P-MR spectrum, the ratios of phosphomonoester (PME)/beta-adenosine triphosphate (ATP), inorganic phosphate (Pi)/beta-ATP and phosphodiester (PDE)/ beta-ATP and the total entropy (H*) were calculated. Mean values and standard deviations were determined and significance of the differences were tested with Student's t test.
  
  
  RESULTS
  For patients, the H* = 4.7 +/- 4.3, PME/beta-ATP 0.72 +/- 0.28, Pi/beta-ATP = 1.00 +/- 0.39, PDE/beta-ATP = 1.68 +/- 0.59. For the volunteers, H* = 7.6 +/- 2.5, PME/beta-ATP = 0.39 +/- 0.15, Pi/beta-ATP = 0.90 +/- 0.19, PDE/beta-ATP = 1.25 +/- 0.28. The total entropy of patients' spectra showed significantly lower values compared with those of volunteers. PME/beta-ATP and PDE/beta-ATP of the patients increased and differed significantly from volunteer data.
  
  
  CONCLUSIONS
  It was demonstrated that the results of in vivo 31P-MR spectroscopy may be described with a single criterion by means of the total entropy.
authors.affiliation: Department of Diagnostic Radiology, Christian-Albrechts-University of Kiel, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Brinkmann
authors.forename: U H
authors.initials: UH
authors.lastname: Melchert
authors.forename: G
authors.initials: G
authors.lastname: Lalk
authors.forename: L
authors.initials: L
authors.lastname: Emde
authors.forename: J
authors.initials: J
authors.lastname: Link
authors.forename: C
authors.initials: C
authors.lastname: Muhle
authors.forename: J C
authors.initials: JC
authors.lastname: Steffens
authors.forename: M
authors.initials: M
authors.lastname: Heller
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D001706:Biopsy; D019277:Entropy; D005260:Female; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism* / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D010759:Phosphorus Isotopes; D014057:Tomography, X-Ray Computed
chemical_list: D010759:Phosphorus Isotopes; D010758:Phosphorus; D000255:Adenosine Triphosphate; D010744:Phosphoric Monoester Hydrolases; D010727:Phosphoric Diester Hydrolases